GRB210619B

This page lists all entries on GRB210619B in GRBweb

Summary Fermi GBM IPN Swift GCN 30261 GCN 30263 GCN 30264 GCN 30265 GCN 30267 GCN 30268 GCN 30269 GCN 30270 GCN 30271 GCN 30272 GCN 30273 GCN 30274 GCN 30275 GCN 30276 GCN 30277 GCN 30278 GCN 30279 GCN 30280 GCN 30281 GCN 30282 GCN 30283 GCN 30284 GCN 30286 GCN 30288 GCN 30289 GCN 30290 GCN 30291 GCN 30292 GCN 30293 GCN 30294 GCN 30299 GCN 30301 GCN 30303 GCN 30304 GCN 30305 GCN 30308 GCN 30309 GCN 30315 GCN 30320 GCN 30338 GCN 30343 GCN 30361 GCN 30386 GCN 30791

Summary table
Variable Value Source
GRB_name_Fermi GRB210619999
T0 23:59:25 UTC GCN_circulars,Fermi LAT Det
ra 319.7183° Swift
decl 33.8504° Swift
pos_error 5.44e-05° Swift
T90 54.785 s Fermi_GBM
T90_error 0.572 s Fermi_GBM
T90_start 23:59:26.180 UTC Fermi_GBM
fluence 3.02e-04 erg/cm² Fermi_GBM
fluence_error 1.23e-07 erg/cm² Fermi_GBM
redshift 1.9370
T100 60.9 s
GBM_located False
mjd 59384.99959490741 GCN_circulars,Fermi LAT Det
Fermi GBM table
GRB_name_Fermi GRB210619999
trigger_name bn210619999
ra 319.7129°
decl 33.8600°
datum 2021-06-19
t_trigger 23:59:25.604 UTC
T90 54.785 s
T90_error 0.572 s
T90_start 23:59:26.180 UTC
fluence 3.02e-04 erg/cm²
fluence_error 1.23e-07 erg/cm²
flux_1024 2.39e+02 erg/cm²/s
flux_1024_error 1.34e+00 erg/cm²/s
flux_1024_time 5.12e-01 erg/cm²/s
flux_64 2.63e+02 erg/cm²/s
flux_64_error 5.54e+00 erg/cm²/s
IPN table
GRB_name GRB210619B
ra 319.7125°
decl 33.8667°
pos_error 5.00e-02°
redshift 1.9370
Swift table
GRB_name GRB210619B
t_trigger 23:59:25 UTC
ra 319.7183°
decl 33.8504°
pos_error 5.44e-05°
T90 60.9 s
fluence 9.50e-05 erg/cm²
redshift 1.9370
GCN 30261 table
GRB_name GRB210619B
GCN_number 30261
Detection_method Swift Det
t_trigger 23:59:25 UTC
ra 319.7130°
decl 33.8600°
Circular_text TITLE: GCN CIRCULAR NUMBER: 30261 SUBJECT: GRB 210619B: Swift detection of a bright burst and optical counterpart DATE: 21/06/20 00:12:00 GMT FROM: David Palmer at LANL P. D'Avanzo (INAF-OAB), M. G. Bernardini (INAF-OAB), A. Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB), K. L. Page (U Leicester), D. M. Palmer (LANL) and T. Sbarrato (INAF-OAB) report on behalf of the Neil Gehrels Swift Observatory Team: At 23:59:25 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210619B (trigger=1056757). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 319.713, +33.860 which is RA(J2000) = 21h 18m 51s Dec(J2000) = +33d 51' 35" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 100 sec. The peak count rate was ~100,000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 00:04:53.4 UT, 328.1 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 319.7161, 33.8495 which is equivalent to: RA(J2000) = 21h 18m 51.86s Dec(J2000) = +33d 50' 58.2" with an uncertainty of 11.1 arcseconds (radius, 90% containment). This location is 38 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 4.27e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 135 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 21:18:52.39 = 319.71831 DEC(J2000) = +33:51:01.6 = 33.85044 with a 90%-confidence error radius of about 0.61 arc sec. This position is 7.5 arc sec. from the center of the XRT error circle. The estimated magnitude is 14.71 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.173. Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)
GCN 30263 table
GRB_name GRB210619B
GCN_number 30263
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30263 SUBJECT: GRB 210619B: Ondrejov D50 detection DATE: 21/06/20 02:47:13 GMT FROM: Martin Jelinek at Astro.Inst-AVCR,Ondrejov M. Jelinek, J. Strobl, R. Hudec, C. Polasek (ASU CAS Ondrejov) report: We observed the position of the bright GRB 210420B (D'Avanzo et al., GCN 30261) with the D50 telescope of the Astronomical Institute Ondrejov, near Prague, Czech Republic. We performed a series of unfiltered exposures starting 23:59:53 UT, between 28 s and 2 h after the trigger. The optical afterglow (Lipunov et al., GCNC30259 & 30262) is clearly detected in single images. We can confirm a decaying nature of the object - the afterglow faded to r'(AB)~17.7 mag during the course of our observations, which were ended by twillight 2.0h after the trigger. The alpha decay by the end of observations was ~0.6, indicating a possible plateau phase.
GCN 30264 table
GRB_name GRB210619B
GCN_number 30264
Detection_method CALET
Circular_text TITLE: GCN CIRCULAR NUMBER: 30264 SUBJECT: GECAM detection of GRB 210619B DATE: 21/06/20 03:40:05 GMT FROM: Zhao Yi at POLAR Y. Zhao, S. L. Xiong, Y. Huang, S. L. Xie, S. Xiao, C. Cai, J. C. Liu, C. Y. Li, Y. Q. Zhang, W. C. Xue, C. Zheng, Z. W. Guo, X. Y. Zhao, Z. H. An, C. Chen, G. Chen, W. Chen, M. Gao, K. Gong, D. Y. Guo, J. J. He, B. Li, C. Li, J. H. Li, Q. X. Li, X. B. Li, X. Q. Li, Y. G. Li, X. H. Liang, J. Y. Liao, J. C. Liu, X. J. Liu, Y. Q. Liu, F. J. Lu, Q. Luo, X. Ma, G. Ou, W. X. Peng, R. Qiao, D. L. Shi, J. Y. Shi, L. M. Song, X. Y. Song, G. X. Sun, X. L. Sun, Y. L. Tuo, C. W. Wang, J. Z. Wang, P. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, S. Yang, M. Yao, Q. B. Yi, B. X. Zhang, C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang, H. M. Zhang, K. Zhang, P. Zhang, S. N. Zhang, Z. Zhang, S. Y. Zhao, S. J. Zheng, X. Zhou (IHEP), report on behalf of GECAM team: During the commissioning phase, GECAM-B was triggered in-flight by a long burst at 2021-06-20T00:00:00.950 UTC (denoted as T0), which was also observed by Swift/BAT (GCN # 30261) and CALET/GBM (trigNum 1308182178). Its alert data was promptly downlinked to the ground through the short message service of BeiDou Navigation Satellite System (BDS). The time latency of the first BeiDou message relative to the trigger time is about 1 minute. According to the BDS alert data, this burst mainly consists of multiple pulses with a duration of more than 60 s. An automatic on-ground localization was calculated using the light curves and spectrum. Although the in-flight calibration of energy response and localization has not been finalized yet, GECAM-B localized this burst to the following position (J2000): Ra: 318.7 deg Dec: 29.2 deg Err: 7.4 deg (1-sigma, statistical only) The current systematic error of location is estimated to be several degrees which could be minimized by the ongoing calibration. This GECAM location is consistent with that of Swift/BAT within the error. The GECAM light curve could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_lc_grd_all_combine_77846400.png The GECAM preliminary location could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_skymap_bdm_77846400_V01.png Please note that all GECAM results here are preliminary. The final analysis will be published in journal papers or GECAM online catalog. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time), which was funded by the Chinese Academy of Sciences (CAS).
GCN 30265 table
GRB_name GRB210619B
GCN_number 30265
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30265 SUBJECT: GRB 210619B: iTelescope T18 detection DATE: 21/06/20 04:51:29 GMT FROM: Albert Kong at NTHU A.K.H. Kong (NTHU, Taiwan) reports We observed the field of GRB 210619B (D'Avanzo et al., GCN 30261) with the T18 0.32m telescope of iTelescope.Net in Nerpio, Spain. The observation was done with a V-band filter beginning at 2021-06-20 02:37:43 UT (about 2.6 hours after the trigger) for 180 sec. The optical afterglow (D'Avanzo et al., GCN 30261) was detected with V=17.9+/-0.2 by calibrating with the APASS DR10 catalogue.
GCN 30267 table
GRB_name GRB210619B
GCN_number 30267
Detection_method Swift-XRT Det
ra 319.7185°
decl 33.8500°
Circular_text TITLE: GCN CIRCULAR NUMBER: 30267 SUBJECT: GRB 210619B: Enhanced Swift-XRT position DATE: 21/06/20 05:32:43 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 1170 s of XRT Photon Counting mode data and 2 UVOT images for GRB 210619B, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 319.71848, +33.85002 which is equivalent to: RA (J2000): 21h 18m 52.44s Dec (J2000): +33d 51' 00.1" with an uncertainty of 2.1 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN 30268 table
GRB_name GRB210619B
GCN_number 30268
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 30268 SUBJECT: GRB 210619B: SARA-KP 0.9m Optical Afterglow Detection DATE: 21/06/20 08:18:35 GMT FROM: Kyle Pellegrin at Clemson University K. Pellegrin, S. Anandagoda, and D. Hartmann report: We observed the field of GRB 210619B detected by Swift BAT (D’Avanzo et al., GCN #30261), Global MASTER-Net (Lipunov et al., GCN #30262), GECAM (Zhao et al., GCN #30264), iTelescope (Kong, GCN #30265), and Ondrejov D50 (M. Jelinek et al., GCN #30263) using the SARA 0.9m optical telescope located at Kitt Peak, AZ, USA, equipped with the Alta-E6-1105 camera. Observation started at 05:19:14 UTC on 2021-06-20 and ended at 06:13:23 UTC on 2021-06-20. We obtained a series of 60s exposure frames in the Johnson-Cousins R filter. We detect the optical afterglow of GRB 210619B at the enhanced Swift-XRT position (Beardmore, et al., GCN #30267). The estimated magnitude of the GRB afterglow was found by stacking 20 images of 60s each in the Johnson-Cousins R band filter. The GRB was visible in each of the stacked images. T_start-T0 (hrs) T_end-T0 (hrs) Start Date (UTC) Filter Magnitude (mag) ---------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------------------- 5.32 5.70 2021-06-20T05:19:14 R 18.51 5.73 6.22 2021-06-20T05:43:59 R 18.77 Photometry is done based on the PanSTARRS catalog. The Southeastern Association for Research in Astronomy (SARA) consortium operates three telescopes: the 0.9-m SARA-KP at Kitt Peak in Arizona, and the 0.6-m SARA-CT at Cerro Tololo in Chile, and the 1.0-m SARA-RM (formerly the JKT) telescope at Roque de los Muchachos Observatory in the Canary Islands. For more information see: Keel et al. (2016): https://iopscience.iop.org/article/10.1088/1538-3873/129/971/015002 ---------------------------------------------------------------------------------------
GCN 30269 table
GRB_name GRB210619B
GCN_number 30269
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 30269 SUBJECT: GRB 210619B: Swift-XRT refined Analysis DATE: 21/06/20 09:37:58 GMT FROM: Phil Evans at U of Leicester K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N. Burrows (PSU), P.A. Evans (U. Leicester) and P. D'Avanzo report on behalf of the Swift-XRT team: We have analysed 6.7 ks of XRT data for GRB 210619B (D'Avanzo et al. GCN Circ. 30261), from 208 s to 24.8 ks after the BAT trigger. The data comprise 1.5 ks in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 30267). The light curve can be modelled with an initial power-law decay with an index of alpha=0.938 (+/-0.014), followed by a break at T+5780 s to an alpha of 1.23 (+/-0.07). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.886 (+/-0.019). The best-fitting absorption column is 2.68 (+/-0.08) x 10^21 cm^-2, in excess of the Galactic value of 2.0 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.88 (+/-0.08) and a best-fitting absorption column of 2.6 (+/-0.3) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.0 x 10^-11 (5.4 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.6 (+/-0.3) x 10^21 cm^-2 Galactic foreground: 2.0 x 10^21 cm^-2 Excess significance: 2.8 sigma Photon index: 1.88 (+/-0.08) If the light curve continues to decay with a power-law decay index of 1.23, the count rate at T+24 hours will be 0.24 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.4 x 10^-12 (1.3 x 10^-11) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01056757. This circular is an official product of the Swift-XRT team.
GCN 30270 table
GRB_name GRB210619B
GCN_number 30270
Detection_method Fermi LAT Det
t_trigger 23:59:25 UTC
ra 319.7000°
decl 33.9000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 30270 SUBJECT: GRB 210619B: Fermi-LAT detection DATE: 21/06/20 10:23:35 GMT FROM: Roberta Pillera at Politecnico and INFN Bari M. Axelsson (KTH & Stockholm Univ.), R. Pillera (Politecnico and INFN Bari) and F. Longo (University and INFN Trieste.) report on behalf of the Fermi-LAT Collaboration: Fermi-LAT has detected high-energy emission from GRB 210619B, which was also detected by Swift (GCN 30261), Global MASTER-net (GCN 30262), Ondrejov D50 (GCN 26263), GECAM (GCN 26264), iTelescope T18 (GCN 30265) and SARA-KP (GCN 30268). The best LAT on-ground location is found to be (RA, Dec) = 319.7, 33.9 (degrees, J2000) with an error radius of 0.13 deg (90% containment, statistical error only). This position is consistent with the XRT localization (GCN 30267). The location of the GRB was outside the LAT FoV at the time of the trigger (T0 = 23:59:25 UT on 2021-06-19) and came into view at T0+200 s. The data from the Fermi-LAT show a significant increase in the event rate that is spatially correlated with the Swift emission with high significance. The highest energy photon is a 8.3 GeV event detected ~410 s after the trigger. The photon flux above 100 MeV in the time interval 200-1000 s after the Swift trigger is (1.6 +/- 1.2) e-06 ph/cm2/s. The estimated photon index above 100 MeV is -1.5 +/- 0.3. The Fermi-LAT point of contact for this burst is Roberta Pillera (roberta.pillera@ba.infn.it). The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
GCN 30271 table
GRB_name GRB210619B
GCN_number 30271
Detection_method correction
Circular_text TITLE: GCN CIRCULAR NUMBER: 30271 SUBJECT: GRB 210619B: Liverpool telescope imaging of a red afterglow DATE: 21/06/20 11:14:52 GMT FROM: Daniel Perley at Liverpool JMU D. A. Perley (LJMU) reports: We acquired multicolor imaging of the optical afterglow of GRB 210619B (D'Avanzo et al., GCN 30261) using the IO:O camera of the 2m robotic Liverpool Telescope. The afterglow was observed twice in the ugriz filters on 2021-06-20 UT, with the first epoch taking place between 02:35:06 and 02:42:40 and the second between 03:49:15 and 03:56:49. Photometry with reference to Pan-STARRS 1 secondary standard stars in the field gives the following magnitudes: t-tburst(d) filter mag unc 0.10772 g 18.58 0.03 0.10879 r 17.82 0.03 0.10984 i 17.44 0.04 0.11227 z 17.17 0.04 0.15920 g 18.93 0.03 0.16028 r 18.11 0.03 0.16133 i 17.74 0.04 0.16376 z 17.47 0.04 These values have not been corrected for Galactic extintion. The colors (after applying a Galactic extinction correction) suggest a moderately dust-reddened afterglow. DisclaimerNone
GCN 30272 table
GRB_name GRB210619B
GCN_number 30272
Detection_method correction
redshift 1.9370
Circular_text TITLE: GCN CIRCULAR NUMBER: 30272 SUBJECT: GRB 210619B: Redshift from OSIRIS/GTC DATE: 21/06/20 11:28:59 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann, C. Thoene, M. Blazek, J.F. Agui Fernandez, (all HETH/IAA-CSIC), L. Izzo (DARK/NBI), N.R. Tanvir (U. Leicester), J.P.U. Fynbo (DAWN/NBI), A. M. Garcia Rodriguez, and G. Gomez (GTC) report: We observed the afterglow of GRB 210619B (D’Avanzo et al. GCN 30261; Lipunov et al. GCN 30262; Jelinek et al. GCN 30263; Zhao et al. GCN 30264; Kong GCN 30265; Beardmore et al. GCN 30267; Pellegrin et al. GCN 30268; Axelsson et al., GCN 30270; Perley GCN 30271) with OSIRIS on the 10.4 m GTC telescope at Roque de los Muchachos Observatory, in the Island of La Palma. The observation started at 2:27 UT (2.45 hr after the burst) and consisted of 3x600 s with grism R1000B, covering the spectral range between 3700 and 7800 AA. In a preliminary reduction with old calibrations we detect a strong continuum with a plethora of absorption features superposed to it. We identify features that include SiII, SiIV, OI, CI, CII, CIV, FeII, AlII, AlIII, NiII, CrII ZnII, as well as fine structure lines of SiII, FeII, NiII at a common redshift of 1.937, which we identify as the redshift of the GRB. We also detect an intervening system with MgII and MgI at z=1.095. Additionally, the flux calibrated spectrum shows a strong broad absorption feature at ~4500AA, resembling a dust bump. This could be consistent with a 2175 AA dust feature due to the intervening absorber. We note that at a redshift of 1.937, the initial prompt emission spike is extremely luminous, and we expect the afterglow to be among the most luminous prompt flashes ever detected. Using the fluence reported on the automatic Swift/BAT analysis page in the 15-350 keV band, we derive an E_iso ~ 1.7e54 erg, without any k-correction. This implies GRB 210619B will likely be among the most energetic GRBs ever detected once a k-correction to the bolometric band is applied. Further analysis is ongoing. We encourage further observations.
GCN 30273 table
GRB_name GRB210619B
GCN_number 30273
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30273 SUBJECT: GRB 210619B: KAIT Optical Detection DATE: 21/06/20 13:48:29 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to the Swift GRB 210619B (D'Avanzo et al., GCN 30261) starting at ~8.05 hours after the Swift trigger. A total of 60x60s images were obtained in the clear (roughly R) filter. The optical afterglow (D'Avanzo et al., GCN 30261; Lipunov et al., GCN 30262; Jelinek et al., GCN 30263; Kong, GCN 30265; Pellegrin et al., GCN 30268; Perley, GCN 30271) was clearly detected in each single image. We measured its brightness of 18.5 +/- 0.1 mag at 8.05 hours after burst, and decayed to be 18.8 +/- 0.1 mag at 11.07 hours after burst, calibrated to the Pan-STARRS1 catalog.
GCN 30274 table
GRB_name GRB210619B
GCN_number 30274
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30274 SUBJECT: GRB 210619B: Liverpool Telescope r'-band observations DATE: 21/06/20 15:37:41 GMT FROM: Martin Blazek at HETH/IAA-CSIC M. Blazek, D. A. Kann (both HETH/IAA-CSIC), A. de Ugarte-Postigo (HETH/IAA-CSIC, DARK/NBI), C. Thoene and J.F. Agui Fernandez (both HETH/IAA-CSIC) report: We observed the afterglow of GRB 210619B (Swift detection: D'Avanzo et al., GCN 30261; GECAM detection: Zhao et al., GCN 30264; Fermi-LAT detection: Axelsson et al., GCN 30270; Afterglow detections: Lipunov et al., GCN 30259; D'Avanzo et al., GCN 30261; Lipunov et al., GCN 30262; Jelinek et al., GCN 30263; Kong, GCN 30265; Pellegrin et al., GCN 30268; Perley, GCN 30271; Zheng & Filippenko, GCN 30273; Redshift: de Ugarte Postigo, GCN 30272) with the 2-m Liverpool Telescope located in La Palma, Spain using IO:O camera. The observation started at 02:57:49 UT on June 20, 2021 (t-t0 = 2.97 hours). We obtained 60x45 seconds exposures in r'. The afterglow is clearly detected in each image. Comparing to 33 check stars from the PanSTARRS catalogue we derived the decay starting with r' = 17.91 +- 0.01 mag and ending at 03:45:43 UT (t-t0 = 3.77) hours with r' = 18.10 +- 0.02 mag Magnitudes are given in AB photometric system. These values have not been corrected for Galactic extintion.
GCN 30275 table
GRB_name GRB210619B
GCN_number 30275
Detection_method Fermi LAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 30275 SUBJECT: GRB 210619B: CAHA 2.2m photometric monitoring DATE: 21/06/20 15:53:18 GMT FROM: Alexander Kann at IAA-CSIC D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), M. Blazek, C. Thoene, J.F. Agui Fernandez, Ginger (all HETH/IAA-CSIC), and J. I. Vico Linares (CAHA) report: We observed the afterglow of GRB 210619B (Swift detection: D'Avanzo et al., GCN 30261; GECAM detection: Zhao et al., GCN 30264; Fermi-LAT detection: Axelsson et al., GCN 30270; Afterglow detections: Lipunov et al., GCN 30259; D'Avanzo et al., GCN 30261; Lipunov et al., GCN 30262; Jelinek et al., GCN 30263; Kong, GCN 30265; Pellegrin et al., GCN 30268; Perley, GCN 30271; Zheng & Filippenko, GCN 30273; Blazek et al., GCN 30274; Redshift: de Ugarte Postigo, GCN 30272) with CAFOS mounted at the 2.2m Calar Alto telescope (Almeria, Spain). After a weather-induced delay, we obtained 80 x 60 s images in Ic. The afterglow is clearly detected in each image. The sequence starts at 01:23 UT and ends at 03:43 UT on 2021-06-20 (0.05836 to 0.15479 d after burst trigger). Comparing to a single star with a magnitude derived from PanSTARRS and transformed following Lupton (2005), we find the afterglow decays from Ic (AB) = 16.75 +/- 0.05 mag to Ic (AB) = 17.45 +/- 0.05 mag. Further observations are planned.
GCN 30276 table
GRB_name GRB210619B
GCN_number 30276
Detection_method Konus-Wind Det
t_trigger 23:59:28.157 UTC
redshift 1.9370
Circular_text TITLE: GCN CIRCULAR NUMBER: 30276 SUBJECT: Konus-Wind detection of GRB 210619B DATE: 21/06/20 15:56:25 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, report: The very bright, long-duration GRB 210619B (Swift-BAT detection: D'Avanzo et al., GCN Circ. 30261; GECAM detection: Zhao et al., GCN Circ. 30264; Fermi-LAT detection: Axelsson et al., GCN Circ. 30270) triggered Konus-Wind at T0=86368.157 s UT (23:59:28.157). The burst light curve shows a bright hard initial episode, which starts at ~T0 and has a duration of ~10 s, followed by weaker pulses. The total burst duration is ~80 s. The emission is seen up to ~15 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB210619_T86368/ As observed by Konus-Wind, the burst had a fluence of 4.60(-0.13,+0.13)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+0.640 s, of 1.54(-0.12,+0.12)x10^-4 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+66.816 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -1.02(-0.03,+0.04), the high energy photon index beta = -2.10(-0.04,+0.03), the peak energy Ep = 261(-13,+14) keV (chi2 = 118/96 dof). The spectrum near the maximum count rate (measured from T0+0.512 to T0+0.768 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.41(-0.11,+0.12), the high energy photon index beta = -2.06(-0.12,+0.09), the peak energy Ep = 572(-81,+98) keV (chi2 = 76/60 dof). Assuming the redshift z=1.937 (de Ugarte Postigo et al., GCN Circ. 30272) and a standard cosmology model with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014), we estimate the following rest-frame parameters: the isotropic energy release E_iso is 4.41(-0.12,+0.12)x10^54 erg, the peak luminosity L_iso is 4.34(-0.34,+0.34)x10^54 erg/s, the rest-frame peak energy of the time-integrated spectrum, Ep,i,z, is 767(-38,+41) keV, and the rest-frame peak energy of the 'peak' spectrum, Ep,p,z, is 1680(-238,+288) keV. With these energetics, the burst lies within the 90% prediction bands for both 'Amati' and 'Yonetoku' relations built for the sample of 138 long KW GRBs with known redshifts (Tsvetkova et al., ApJ 850 161, 2017), see http://www.ioffe.ru/LEA/GRBs/GRB210619_T86368/GRB210619B_rest_frame.pdf. Among the KW GRB sample, GRB 210619B is within top 4% in the terms of E_iso and have L_iso comparable to the most luminous GRB 110918A (Frederiks et al., ApJ 779, 151, 2013). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN 30277 table
GRB_name GRB210619B
GCN_number 30277
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30277 SUBJECT: GRB 210619B: Xinglong TNT optical observations DATE: 21/06/20 16:13:35 GMT FROM: Liping Xin at NAOC, SVOM L. P. Xin (NAOC), X. Li (THU), Y. L. Qiu(NAOC), J. Y. Wei(NAOC), J. Wang(GXU), L. H. Li (NAOC), C. Wu(NAOC), E. W. Liang(GXU), X. H. Han (NAOC), A. Y. Zhou (NAOC) and J. S. Deng(NAOC) report: We began to observe GRB 210619B (Swift detection: D'Avanzo et al., GCN 30261; GECAM detection: Zhao et al., GCN 30264; Fermi-LAT detection: Axelsson et al., GCN 30270; Konus-Wind detection: Svinkin et al., GCN 30276; Afterglow detections: Lipunov et al., GCN 30259; D'Avanzo et al., GCN 30261; Lipunov et al., GCN 30262; Jelinek et al., GCN 30263; Kong, GCN 30265; Pellegrin et al., GCN 30268; Perley, GCN 30271; Zheng & Filippenko, GCN 30273; Redshift: de Ugarte Postigo, GCN 30272, Blazek et al., GCN 30274; Kann et al., 30275) with Xinglong TNT telescope, China, at 15:23:44 (UT), 20th. June. 2021, about 14.43 hours after the burst, A series of R and B band images were obtained. The afterglow is clear detected in our single image with a magnitude of 19.0 mag in R band comparing to several nearby USNO B1.0 stars. Observations are still continuing. We acknowledge the excellent support from Xinglong staff YuGuang Sun. The message may be cited.
GCN 30278 table
GRB_name GRB210619B
GCN_number 30278
Detection_method Swift-UVOT Det
ra 319.7183°
decl 33.8504°
Circular_text TITLE: GCN CIRCULAR NUMBER: 30278 SUBJECT: GRB 210619B: Swift/UVOT Detection DATE: 21/06/20 16:42:40 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (UCL-MSSL) and P. D'Avanzo (INAF-OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 210619B 136 s after the BAT trigger (D'Avanzo et al., GCN Circ. 30261). A source consistent with the XRT position (Beardmore et al., GCN Circ. 30267) was detected in the initial UVOT exposures consistent with the reported afterglow by Lipunov et al. (GCN Circ. 30259), Jelinek et al. (GCN Circ. 30263), Kong (GCN Circ. 30265), Kellegrin et al. (GCN Circ. 30268), and Zheng & Filippenko (GCN Circ. 30273). A redshift measurement of z=1.937 was reported by de Ugarte Postigo et al. (GCN Circ. 20272) which puts the Lyman break right at the center of the UVOT uvm2 filter. The preliminary UVOT position is: RA (J2000) = 21:18:52.38 = 319.71825 (deg.) Dec (J2000) = +33:51:01.6 = 33.85044 (deg.) with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 136 285 147 14.67 +/- 0.02 white 794 814 19 16.66 +/- 0.06 v 679 699 19 15.59 +/- 0.10 b 604 624 20 16.39 +/- 0.08 u 348 598 246 15.60 +/- 0.03 w1 729 1107 39 17.22 +/- 0.19 m2 704 1776 117 >19.3 w2 655 1726 136 19.20 +/- 0.31 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.173 in the direction of the burst (Schlegel et al. 1998).
GCN 30279 table
GRB_name GRB210619B
GCN_number 30279
Detection_method Fermi GBM Det
t_trigger 23:59:25.600 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 30279 SUBJECT: GRB 210619B: Fermi GBM detection DATE: 21/06/20 18:40:56 GMT FROM: Suraj Poolakkil at UAH S. Poolakkil (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 23:59:25.60 UT on 19 June 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 210619B (trigger 645839970 / 210619999) which was also detected by the Swift/BAT (D'Avanzo et al. 2021, GCN 30261), Fermi-LAT (Axelsson et al. 2021, GCN 30270) and Konus-Wind (Svinkin et al. 2021, GCN 30276). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 109 degrees. The GBM light curve consists of a single peak followed by some extended emission with a duration (T90) of about 55 s (50-300 keV). The time-averaged spectrum from T0 s to T0+61.4 s is best fit by a Band function, with Epeak = 210 +/- 3 keV, alpha = -0.86 +/- 0.01 and beta = -1.99 +/- 0.01. The event fluence (10-1000 keV) in this time interval is (307.93 +/- 0.9830)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.51 s in the 10-1000 keV band is 238.6 +/- 1.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog:https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page:https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN 30280 table
GRB_name GRB210619B
GCN_number 30280
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30280 SUBJECT: GRB 210619B: Liverpool Telescope First Hour Observations DATE: 21/06/20 19:09:26 GMT FROM: Manisha Shrestha at Liverpool John Moores U M. Shrestha (Liverpool JMU), A. Gomboc (Univ. Nova Gorica), C. Guidorzi (Univ. Ferrara) , S. Kobayashi (LJMU), A. Melandri (INAF), C. Mundell (Univ. Bath), R. Smith (LJMU) , I.A. Steele (LJMU), report on behalf of a wider collaboration: We observed the field of Swift GRB 210619B (D'Avanzo et al. GCN 30261; Jelinek et al. GCN 30263; Lipunov et al. GCN 30259; Zhao et al. GCN 30261; Kong et al. GCN 30265; Axelsson et al. GCN 30270; de Ugarte Postigo et al. GCN 30272; Zheng et al. GCN 30273; Blazek et al. GCN 30274; Kann et al. GCN 30275; Svinkin et al. GCN 30276; Xin et al. GCN 30277; Perley et al. GCN 30271 ) with the 2.0m Liverpool Telescope (LT), La Palma on 2021 June 20 starting at 00:21:14.141 UT for a period of 2 hours using the MOPTOP optical imaging polarimeter in the r band. Data was calibrated with respect to nearby APASS secondary standard stars. We confirm the optical counterpart reported by Swift UVOT (GCN 30261). At T=1318 seconds after the BAT trigger time, we measure r = 16.1 mag. Detailed analysis is ongoing. ________________________________ Important Notice: Liverpool John Moores University was established as a Higher Education Corporation under section 121 of the Education Reform Act 1988. Further information about Liverpool John Moores University can be found at https://www.ljmu.ac.uk/about-us The information in this email and any attachments is for the sole use of the intended recipient(s). If you are not an intended recipient, or a person responsible for delivering it to an intended recipient, you should delete it from your system immediately without disclosing its contents elsewhere and advise the sender by returning the email or by telephoning a number contained in the body of the email. No responsibility is accepted for loss or damage arising from viruses or changes made to this message after it was sent and the recipient must ensure that the email (and attachments) are virus free. The views contained in this email are those of the author and not necessarily those of Liverpool John Moores University. We will use the personal data information provided by you to respond to your email. For information about how we process personal data and monitor communications please see our Privacy Notice. https://www.ljmu.ac.uk/legal/privacy-and-cookies
GCN 30281 table
GRB_name GRB210619B
GCN_number 30281
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30281 SUBJECT: GRB 210619B: steepening of the decay observed at the D50 DATE: 21/06/21 00:55:28 GMT FROM: Martin Jelinek at Astro.Inst-AVCR,Ondrejov M. Jelinek, J. Strobl, R. Hudec, C. Polasek (ASU CAS Ondrejov) report: We observed the optical afterglow of GRB 210619B (D'Avanzo et al. GCN 30261; Jelinek et al. GCN 30263; Lipunov et al. GCN 30259; Zhao et al. GCN 30261; Kong et al. GCN 30265; Axelsson et al. GCN 30270; de Ugarte Postigo et al. GCN 30272; Zheng et al. GCN 30273; Blazek et al. GCN 30274; Kann et al. GCN 30275; Svinkin et al. GCN 30276; Xin et al. GCN 30277; Perley et al. GCN 30271, Shrestha et al. GCN 30280) with the D50 in Ondrejov through difficult conditions with some passing clouds. On a combined (86x60s, Sloan r') image with the mean exposure time 0.98 days post burst we measure r'(AB) = 20.2 +- 0.2. This is significantly below any extrapolation of photometric points published before, and suggests a break and a steepening of the decay.
GCN 30282 table
GRB_name GRB210619B
GCN_number 30282
Detection_method Swift-BAT Det
ra 319.7180°
decl 33.8500°
Circular_text TITLE: GCN CIRCULAR NUMBER: 30282 SUBJECT: GRB 210619B: Swift-BAT refined analysis DATE: 21/06/21 02:26:59 GMT FROM: Amy Lien at GSFC A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), P. D'Avanzo (INAF-OAB), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 210619B (trigger #1056757) (D'Avanzo et al., GCN Circ. 30261). The BAT ground-calculated position is RA, Dec = 319.718, 33.850 deg which is RA(J2000) = 21h 18m 52.3s Dec(J2000) = +33d 50' 58.6" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 36%. The mask-weighted light curve shows a bright pulse that starts at ~T0 and peaks at ~T+1 s, and is followed by several overlapping pulses that last till ~T+105 s. T90 (15-350 keV) is 60.90 +- 0.28 sec (estimated error including systematics). The time-averaged spectrum from T-0.25 to T+105.38 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.41 +- 0.02. The fluence in the 15-150 keV band is 9.5 +- 0.1 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T+0.95 sec in the 15-150 keV band is 115.0 +- 2.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1056757/BA/
GCN 30283 table
GRB_name GRB210619B
GCN_number 30283
Detection_method IPN Triangulation
Circular_text TITLE: GCN CIRCULAR NUMBER: 30283 SUBJECT: GRB 210619B: SRG/ART-XC detection DATE: 21/06/21 06:37:17 GMT FROM: Sergey Molkov at Space Research Inst., Moscow V. Levin, S. Molkov, I. Mereminskiy, А. Lutovinov, A. Semena and E. Filippova (IKI RAN) report on behalf of SRG/ART-XC team: At 23:59:21 UT on 19/06/2021 the Mikhail Pavlinsky ART-XC telescope on board the Spektr-RG observatory detected a short peak in the 40-120 keV count rate. This peak is associated with the luminous GRB210619B registered simultaneously by other space-bourne missions (Swift/BAT (D'Avanzo et al. 2021, GCN 30261), GECAM (Zhao et al. 2021, GCN 30264), Fermi-LAT (Axelsson et al. 2021, GCN 30270), Konus-Wind (Svinkin et al. 2021, GCN 30276), Fermi/GBM (Poolakkil and Meegan 2021, GCN 30279)). The burst light curve is similar to what observed by other telescopes, with a prominent initial peak (that lasted for 6 s and having a typical fast rise exponential decay form) and several consecutive peaks, roughly coincident with ones detected by Konus-Wind. The angle between telescope axis and the burst was 45 degrees, which means that the burst emission had penetrated through the side shield of ART-XC detectors. This significantly complicates the spectral analysis, which will be presented elsewhere. The Mikhail Pavlisky ART-XC is an X-ray telescope working in the hard X-ray band (above 4 keV) in the Langrangian point L2. It could observe brightest GRBs through its side/back shielding, providing an additional leverage for the IPN-like triangulation of such events.
GCN 30284 table
GRB_name GRB210619B
GCN_number 30284
Detection_method CALET
Circular_text TITLE: GCN CIRCULAR NUMBER: 30284 SUBJECT: GRB 210619B: CALET Gamma-Ray Burst Monitor detection DATE: 21/06/21 10:39:15 GMT FROM: Valentin Pal'shin at AGU Y. Kawakubo (LSU), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The long bright GRB 210619B (Swift detection: D'Avanzo et al., GCN Circ. 30261, Lien et al., GCN Circ. 30282; GECAM detection: Zhao et al., GCN Circ. 30264; Fermi-LAT detection: Axelsson et al., GCN Circ. 30270; Konus-Wind detection: Svinkin et al., GCN Circ. 30276; Fermi GBM detection: Poolakkil and Meegan, GCN Circ. 30279; SRG/ART-XC detection: Levin et al., GCN Circ. 30283; https://gcn.gsfc.nasa.gov/other/210619B.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 23:59:21.940 UTC on 19 June 2021 (http://cgbm.calet.jp/cgbm_trigger/flight/1308182178/index.html). The burst signal was seen by all CGBM detectors. The burst light curve shows the bright initial pulse which starts at T+3.5 sec and peaks at T+4.3 sec, followed by several weaker pulses which end at T+85.4 sec. The T90 and T50 durations measured by the SGM data are 49.9 +- 1.8 sec and 14.4 +- 0.6 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1308182178/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN 30286 table
GRB_name GRB210619B
GCN_number 30286
Detection_method Optical
ra 319.7183°
decl 33.8503°
Circular_text TITLE: GCN CIRCULAR NUMBER: 30286 SUBJECT: GRB 210619B: GIT optical follow-up and confirmation of jet-break DATE: 21/06/21 11:36:42 GMT FROM: Harsh Kumar at Indian Inst of Tech,Bombay H. Kumar(IITB), U. Stanzin (IAO), V. Bhalerao(IITB), G. C. Anupama(IIA), S. Barway(IIA) report on behalf of the GIT team: We observed GRB 210619B detected by Swift-BAT (D'Avanzo et al. GCN #30261) also see(Lipunov et al. GCN #30259; Zhao et al. GCN #30261; Jelinek et al. GCN #30263; Kong et al. GCN #30265; Axelsson et al. GCN #30270; Perley et al. GCN #30271; de Ugarte Postigo et al. GCN #30272; Zheng et al. GCN #30273; Blazek et al. GCN #30274; Kann et al. GCN #30275; Svinkin et al. GCN #30276; Xin et al. GCN #30277; Shrestha et al. GCN #30280; Jelinek et al. GCN #30281), with 0.7m GROWTH-India Telescope (GIT). We obtained multiple 300-sec exposures in the g', r' and i' filters starting at 2021-06-20T18:04:27 UT. We clearly detected the afterglow in our stacked images at R.A.(J2000)= 21:18:52.39, DEC.(J2000)= +33:51:01.10. The photometric results follow as: ------------------------------------------------------------------- JD (mid) | T_mid - T0(hrs) | Filter | Magnitude (AB) | ------------------------------------------------------------------- 2459386.26006 | 18.25 | g' | 21.133 +/- 0.07 | 2459386.27823 | 18.69 | r' | 20.184 +/- 0.05 | 2459386.29675 | 19.14 | i' | 20.091 +/- 0.06 | 2459386.33501 | 20.05 | g' | 21.142 +/- 0.07 | ------------------------------------------------------------------- Our r' magnitude is significantly fainter as compared to the extrapolation of power-law from previous observations. We thus confirm jet-break in GRB 210619B, first suggested by Jelinek et al. GCN #30281. The magnitudes are calibrated against PanSTARRS (Flewelling et al., 2018) and not corrected for Galactic extinction. The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (https://sites.google.com/view/growthindia/). It is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA).
GCN 30288 table
GRB_name GRB210619B
GCN_number 30288
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30288 SUBJECT: GRB 210619B: REM optical/NIR afterglow detection DATE: 21/06/21 13:00:05 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo, A. Melandri, S. Covino, D. Fugazza, (INAF-OAB) on behalf of the REM team, report: We observed the field of GRB 210619B (D'Avanzo et al., GCN Circ. 30261) with the REM 60cm robotic telescope located at the ESO premise of La Silla (Chile). The observations were carried in the g, r, i, z, J, H and K bands, starting on 2021 June 20 at 06:07:59 UT (i.e. 6.14 hours after the burst) and lasting for about one hour. The optical/NIR afterglow (D'Avanzo et al., GCN Circ. 30261) is detected in all bands. From preliminary photometry we derive the following magnitudes: r = 18.52 +/- 0.12 (AB; calibrated against the Pan-STARRS catalogue) J = 17.10 +/- 0.24 H = 16.61 +/- 0.25 K = 15.13 +/- 0.23 (Vega; calibrated against the 2MASS catalogue) at a mid time of t-t0 = 6.3 hours.
GCN 30289 table
GRB_name GRB210619B
GCN_number 30289
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 30289 SUBJECT: GRB 210619B: TNG NIR observations of the afterglow DATE: 21/06/21 13:02:39 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo (INAF-OAB), V. D'Elia (ASI-SSDC), A. Melandri, G. Tagliaferri (INAF-OAB), A. Rossi (INAF-OAS), L. Di Fabrizio, D. Carosati (INAF-TNG) on behalf of the CIBO collaboration report: We observed the NIR afterglow of GRB 210619B (D'Avanzo et al., GCN Circ. 30261) with the Italian 3.6m TNG telescope equipped with the near-infrared camera NICS. A series of images were obtained with the J and K filters on 2021-06-21 from 01:27:06 UT to 02:49:36 UT (i.e. at a mid time of about 1.09 days after the burst). With preliminary photometry we derive the following magnitudes: J = 17.90 +/- 0.05 K = 16.43 +/- 0.11 (Vega; calibrated against the 2MASS catalogue).
GCN 30290 table
GRB_name GRB210619B
GCN_number 30290
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30290 SUBJECT: GRB 210619B: SEDM Optical Observations DATE: 21/06/21 13:23:39 GMT FROM: Virginia Cunningham at U of MD V. Cunningham (U of Maryland), J. D. Neill (Caltech), S. B. Cenko (NASA GSFC), and R. Walters (Caltech) report on behalf of the SEDM team: We observed the optical counterpart to GRB 210619B (D'Avanzo et al., GCN 30261) with the Spectral Energy Distribution Machine (SEDM) on the 60 inch telescope at Palomar Observatory. The SEDM is a low resolution (R ~ 100) integral field unit spectrometer with a multi-band (ugri) rainbow camera imager (see Blagorodnova et al. 2018, PASP, 130, 035003, and Rigault et al. 2019, A&A, 627, A115). The SEDM began observing the optical counterpart at 06:37:52 UTC (6.5 hours after the burst trigger time). We performed a 2880 s exposure over the wavelength range 3800-9200 A. The continuum emission is well-fit by a power law spectrum with index alpha = 2.8 (f_nu ~ nu^-alpha). The noise level of the spectrum, especially at wavelengths bluer than 5000 A, make it difficult to confirm the redshift reported by OSIRIS/GTC (GCN 30272). [GCN OPS NOTE(22jun21): Per author's request, the error in the sentence: "The SEDM began observing the optical counterpart at 00:01:33 UTC (1.5 hours after the burst trigger time)" and should be replaced with: "The SEDM began observing the optical counterpart at 06:37:52 UTC (6.5 hours after the burst trigger time)".]
GCN 30291 table
GRB_name GRB210619B
GCN_number 30291
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30291 SUBJECT: GRB 210619B: SAO RAS optical observations DATE: 21/06/21 13:32:22 GMT FROM: Moskvitin Alexander at SAO RAS A. S. Moskvitin and O. A. Maslennikova (SAO RAS), report on behalf of the GRB follow-up team. We observed the field of Swift GRB 210619B (D'Avanzo et al., GCNs #30261, #30288, #30289; Jelinek et al., GCNs #30263, #30281; Lipunov et al., GCN #30259; Zhao et al., GCN #30261; Kong et al., GCN #30265; Axelsson et al., #GCN 30270; de Ugarte Postigo et al., GCN #30272; Zheng et al., GCN #30273; Blazek et al., GCN #30274; Kann et al., GCN #30275; Svinkin et al., GCN #30276; Xin et al., GCN $30277; Perley et al., GCN #30271, Shrestha et al., GCN #30280, Kumar et al. GCN #30286; Cunningham et al., GCN #30290) with the SAO RAS 1-m telescope Zeiss-1000 + CCD-photometer. We obtained 6 x 300 sec. frames in Rc band on June 20/21 (23:31:43--00:03:05 UT), T_mid-T0 = 0.99166d. The OT is clearly detected in the stacked frame with the brightness R = 19.8 +/- 0.1 (based on nearby USNO-B1 stars).
GCN 30292 table
GRB_name GRB210619B
GCN_number 30292
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30292 SUBJECT: GRB 210619B: iTelescope optical afterglow observation DATE: 21/06/21 14:08:05 GMT FROM: Filipp Dmitrievich Romanov at Amateur astronomer I observed the field of GRB 210619B (D'Avanzo et al., GCN Circ. 30261) using remote telescope T18 (0.32-m f/8.0 reflector + CCD) of iTelescope.Net in observatory AstroCamp at Nerpio (Spain). Five images (with exposures 300 seconds, BINx1) were obtained with Astrodon luminance filter on 2021-06-20 from 23:06:46 to 23:36:44 UTC (until the roof was closed due to poor weather). I detected faint (SNR ~ 3) optical afterglow with UVOT position in stacked image (mid time = 23:21:43 UTC, that is 0.974 days after the trigger) and measured its magnitude from comparison to r' magnitudes of nearby stars from Pan-STARRS DR1 catalogue (Chambers et al., 2016): 20.5 +/- 0.4. Magnitude was not corrected for Galactic extinction. Stacked image available here: https://www.flickr.com/photos/filipp-romanov/51261591951
GCN 30293 table
GRB_name GRB210619B
GCN_number 30293
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30293 SUBJECT: GRB 210619B: 1.5m OSN optical observation DATE: 21/06/21 15:48:49 GMT FROM: Youdong HU at IAA-CSIC Y.-D. Hu, A. Sota, T.-R. Sun, A. J. Castro-Tirado, M. D. Caballero-Garcia, M. A. Castro Tirado and E. Fernandez-Garcia (IAA-CSIC), on behalf of a larger collaboration, report: Following the detection of GRB 210619B by Swift (D'Avanzo et al. GCN 30261), GECAM (Zhao et al. GCN 30264), CALET (Kawakubo et al. GCNC 30284), SRG/ART-XC (Levin et al. GCNC 30283), Fermi-LAT (Axelsson et al. GCNC 30270), Konus-Wind (Svinkin et al. GCN 30276) and Fermi/GBM (Poolakkil et al. GCNC 30279), images in BVRI bands were obtained at the 1.5m OSN telescope in Granada (Spain) starting on Jun 20, 22:33 UT. We detect the optical afterglow (Lipunov et al. GCNC 30259; Lipunov et al. GCNC 30262; Jelinek et al. GCNC 30263; Kong et al. GCNC 30265; Pellegrin et al. GCNC 30268; D. Perley GCNC 30271; de Ugarte Postigo et al. GCNC 30272; Zheng et al. GCNC 30273; Blazek et al. GCNC 30274; Kann et al. GCNC 30275; Xin et al. GCNC 30277; Kuin et al. GCNC 30278, Shrestha et al. GCNC 30280; Jelinek et al. GCNC 30281; Kumar et al. GCNC 30286; D'Avanzo et al. GCNC 30288; D'Avanzo et al. GCNC 30289; Cunningham et al. GCNC 30290; and Moskvitin et al. GCNC 30291) for which we measure R = 19.9 +/- 0.2 (~0.94 d after trigger). Further observations are ongoing. We thank the staff at OSN for their excellent support.
GCN 30294 table
GRB_name GRB210619B
GCN_number 30294
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30294 SUBJECT: GRB 210619B: NOT optical observations DATE: 21/06/21 16:41:37 GMT FROM: Dong Xu at NAOC/CAS Z.P. Zhu (NAOC, HUST), A. de Ugarte Postigo (HETH, IAA-CSIC), D. B. Malesani (DTU Space), L. Izzo (DARK/NBI), D. Alexander Kann (HETH, IAA-CSIC), D. Xu (NAOC), A. Amanda Djupvik (NOT) report on behalf of a larger collaboration: We observed GRB 210619B detected by Swift/BAT (D'Avanzo et al., GCN 30261) with the Nordic Optical Telescope (NOT) equipped with StanCAM. Observations started at 04:16:27 UT on 2021-06-21, and we obtained 3x300 s exposures in the Bessel R filter, 5x200 s in the SDSS z-filter, and 3x300 s in the i-filter (similar to SDSS i). The previously reported optical afterglow (e.g., Lipunov et al. GCN 30259; Zhao et al. GCN 30261; Jelinek et al. GCN 30263; Kong et al. GCN 30265; Axelsson et al. GCN 30270; Perley et al. GCN 30271; de Ugarte Postigo et al. GCN 30272; Zheng et al. GCN 30273; Blazek et al. GCN 30274; Kann et al. GCN 30275; Svinkin et al. GCN 30276; Xin et al. GCN 30277; Shrestha et al. GCN 30280; Jelinek et al. GCN 30281; Kumar et al., GCN 30286; D'Avanzo et al., GCN 30288; D'Avanzo et al., GCN 30289; Moskvitin et al., GCN 30291; GCN 30292) is clearly detected in our images. Preliminary photometric results are as follows: T_mid/d Filter Mag MagErr MagSysten 1.18338 R 19.92 0.02 Vega 1.21390 i 19.65 0.02 AB 1.20022 z 18.88 0.11 AB calibrated by the PS1 catalogue.
GCN 30299 table
GRB_name GRB210619B
GCN_number 30299
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30299 SUBJECT: GRB 210619B: AbAO optical observations DATE: 21/06/22 12:13:52 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO), V. R. Ayvazian (AbAO), G. V. Kapanadze (AbAO), N. Pankov (HSE, IKI) report on behalf of IKI GRB FuN: We observed the field of GRB 210619B (D'Avanzo et al., GCN 30261; Zhao et al., GCN 30264; Axelsson et al., GCN 30270; Svinkin et al., GCN 30276; Levin et al., GCN 30283; Kawakubo et al., GCN 30284) with AS-32 telescope of Abastumani observatory (AbAO) in R-filter on June, 21. The optical afterglow (Lipunov et al., GCN 30259; D'Avanzo et al., GCNs 30261, 30288; Lipunov et al., GCN 30262; Jelinek et al., GCNs 30263, 30281; Kong, GCN 30265; Pellegrin et al., GCN 30268, Perley et al., GCN 30271; Zheng and Filippenko, GCN 30273; Blazek et al., GCN 30274; Kann et al., GCN 30275; Xin et al., GCN 30277; Shrestha et al., GCN 30280; Kumar et al., GCN 30286; Moskvitin et al., GCN 30291; Romanov, GCN 30292; Hu et al., GCN 30293; Zhu et al., GCN 30294) is detected in the stacked image. Preliminary photometry of the afterglow is following Date UT start t-T0 Filter Exp. OT Err. UL(3sigma) (mid, days) (s) 2021-06-21 23:16:31 1.98931 R 55*60 20.6 0.3 20.6 The photometry is based on the nearby stars: USNO-B1.0 R2 1238-0493928 15.08 1238-0494511 15.67
GCN 30301 table
GRB_name GRB210619B
GCN_number 30301
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30301 SUBJECT: GRB 210619B: possibility of lensed visible afterglow? DATE: 21/06/22 13:01:03 GMT FROM: Jean-Luc Atteia at IRAP Based on the fact that GRB 210619B (1) had a bright visible afterglow that remained above magnitude 20 for nearly one day (2), and considering the detection of an intervening system in its optical spectrum (3), we point out the possibility of lensed afterglow emission from this GRB, in the coming weeks or months (4), that could be detectable with moderate size telescopes. (1) (D'Avanzo et al. GCN 30261 ; Zhao et al. GCN 30264 ; Kawakubo et al. GCNC 30284 ; Levin et al. GCNC 30283 ; Axelsson et al. GCNC 30270 ; Svinkin et al. GCN 30276 ; Poolakkil et al. GCNC 30279). (2) (Lipunov et al. GCNC 30259; Lipunov et al. GCNC 30262; Jelinek et al. GCNC 30263; Kong et al. GCNC 30265; Pellegrin et al. GCNC 30268; D. Perley GCNC 30271; Zheng et al. GCNC 30273; Blazek et al. GCNC 30274; Kann et al. GCNC 30275; Xin et al. GCNC 30277; Kuin et al. GCNC 30278, Shrestha et al. GCNC 30280; Jelinek et al. GCNC 30281; Kumar et al. GCNC 30286; D'Avanzo et al. GCNC 30288; D'Avanzo et al. GCNC 30289; Cunningham et al. GCNC 30290; Moskvitin et al. GCNC 30291; Romanov GCNC 30292 ; Hu et al. GCNC 30293, Zhu et al. GCNC 30294). (3) de Ugarte Postigo et al. GCNC 30272. (4) Oguri, M. (2019) Reports on Progress in Physics, 82, 126901.
GCN 30303 table
GRB_name GRB210619B
GCN_number 30303
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30303 SUBJECT: GRB 210619B: Further SAO RAS optical observations DATE: 21/06/22 14:07:24 GMT FROM: Moskvitin Alexander at SAO RAS A. S. Moskvitin and O. A. Maslennikova (SAO RAS), report on behalf of the GRB follow-up team. We observed the field of Swift GRB 210619B (D'Avanzo et al., GCNs #30261, #30288, #30289; Jelinek et al., GCNs #30263, #30281; Lipunov et al., GCN #30259; Zhao et al., GCN #30261; Kong et al., GCN #30265; Axelsson et al., #GCN 30270; de Ugarte Postigo et al., GCN #30272; Zheng et al., GCN #30273; Blazek et al., GCN #30274; Kann et al., GCN #30275; Svinkin et al., GCN #30276; Xin et al., GCN #30277; Perley et al., GCN #30271, Shrestha et al., GCN #30280, Kumar et al. GCN #30286; Cunningham et al., GCN #30290; Romanov, GCN #30291; Hu et al., GCN #30293; Zhu et al., GCN #30294; Belkin et al., GCN #30299; Atteia, GCN #30301) with the SAO RAS 1-m telescope Zeiss-1000 + CCD-photometer. We obtained 13 x 300 sec. frames in Rc band on June 21/22 (22:55:13--00:13:13 UT), T_mid-T0 = 1.98251d. The OT is clearly detected in the stacked frame with the brightness R = 20.73 +/- 0.08 (based on nearby USNO-B1 stars).
GCN 30304 table
GRB_name GRB210619B
GCN_number 30304
Detection_method INTEGRAL
Circular_text TITLE: GCN CIRCULAR NUMBER: 30304 SUBJECT: GRB 210619B: SPI-ACS/INTEGRAL observations DATE: 21/06/22 16:17:53 GMT FROM: Alexei Pozanenko at IKI, Moscow P. Minaev, A. Pozanenko, I. Chelovekov, S. Grebenev (IKI) report on behalf of IKI GRB FuN: We report observations of GRB 210619B with the INTEGRAL/SPI-ACS detector (publicly available data). The burst was previously detected in several X-/gamma-ray experiments (D'Avanzo et al., GCN 30261; Axelsson et al., GCN 30270; Poolakkil et al., GCN 30279; Levin et al., GCN 30283; Kawakubo et al., GCN 30284). GRB 210619B was detected by SPI-ACS at (UTC) 2021-06-19T23:59:25. Its duration in the SPI-ACS energy band (> 80 keV) is T_90 = 50.9 ± 0.1 s. Comparing the fluxes measured from a number of long-duration GRBs simultaneously recorded by SPI-ACS and Fermi/GBM (Chelovekov et al., in preparation) we estimated the GRB 210619B fluence to be 1.7e-4 erg/cm^2 in the 10-1000 keV band (the 95% confidence region which includes systematics was 4.9e-5 - 5.9e-4 erg/cm^2). We did not detect any precursor with durations of 0.1 - 5 s during 500 s prior to the trigger time. Also we did not detect any signature of an extended emission up to 1000 s after the trigger time. The SPI-ACS light curve of GRB 210619B can be found at http://grb.rssi.ru/GRB210619B/GRB210619B_SPI-ACS_LC.png
GCN 30305 table
GRB_name GRB210619B
GCN_number 30305
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30305 SUBJECT: GRB 210619B: Abbey Ridge Observatory optical afterglow observation DATE: 21/06/22 17:00:39 GMT FROM: Filipp Dmitrievich Romanov at Amateur astronomer Filipp D. Romanov (Russia) and David J. Lane (Saint Mary's University, Canada) report: Filipp Romanov observed optical afterglow of GRB 210619B (D'Avanzo et al., GCN Circ. 30261) remotely using 0.355-m f/6.2 Schmidt-Cassegrain telescope of Abbey Ridge Observatory (it is owned by Dave Lane) in Canada, on 2021-06-21. Eight images (with exposures: 660, 840, 720, 840, 720, 720, 780 and 720 seconds) were obtained with Cousins R filter from 02:29:26 to 04:56:00 UTC. The optical afterglow (with UVOT position) is clearly (SNR = 11) visible in the stacked image (mid time = 03:42:42 UTC, that is 1.155 days after the trigger). Romanov measured its magnitude comparing to transformed (using formula Rc=r’-0.22 from Dymock & Miles, 2009) r' magnitudes of nearby stars from Pan-STARRS DR1 catalogue (Chambers et al., 2016). The measured magnitude = 20.0 +/- 0.2. Magnitude was not corrected for Galactic extinction. Stacked image available here: http://www.abbeyridgeobservatory.ca/images/GRB210619B.jpg
GCN 30308 table
GRB_name GRB210619B
GCN_number 30308
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30308 SUBJECT: GRB 210619B: Mini-MegaTORTORA early optical observations DATE: 21/06/23 11:18:23 GMT FROM: Sergey Karpov at SAO RAS S.Karpov (FZU CAS, Czech Republic; SAO RAS and Kazan Federal University, Russia) G.Beskin (SAO RAS and Kazan Federal University, Russia), N. Lyapsina (SAO RAS, Russia), E.Ivanov, E.Katkova, A.Perkov (OJS RPC PSI, Russia), A.Biryukov (SAI MSU and Kazan Federal University, Russia), V.Sasyuk (Kazan Federal University, Russia) Mini-MegaTORTORA nine-channel wide-field monitoring system with high temporal resolution responded to the BAT trigger and observed the position of GRB 210619B (D'Avanzo et al., GCN 30261) since 2021-06-20 00:00:20 UT (T+55 s, during the ongoing gamma-ray emission) and until 2021-06-20 00:10:28 UT (T + 663 s). The system simultaneously acquired series of frames with 1 s exposures, 5 s exposures and 30 s exposures in white light, 10 s exposures in B filter, and 10 s exposures in V filter. The transient was clearly detectable in all acquired sequences except B filter ones. Overall behaviour of the early light curve is consistent with the smooth decay reported by Jelinek et al. (GCN 30263), with no large-amplitude variability apparent in high temporal resolution data. Mini-MegaTORTORA belongs to Kazan Federal University and is located at Special Astrophysical Observatory near Russian 6-m telescope. The message may be cited.
GCN 30309 table
GRB_name GRB210619B
GCN_number 30309
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30309 SUBJECT: GRB 210619B: Even further SAO RAS optical observations DATE: 21/06/23 13:34:33 GMT FROM: Moskvitin Alexander at SAO RAS A. S. Moskvitin and O. A. Maslennikova (SAO RAS), report on behalf of the GRB follow-up team. We observed the field of Swift GRB 210619B (D'Avanzo et al., GCNs #30261, #30288, #30289; Jelinek et al., GCNs #30263, #30281; Lipunov et al., GCN #30259; Zhao et al., GCN #30261; Kong et al., GCN #30265; Axelsson et al., #GCN 30270; de Ugarte Postigo et al., GCN #30272; Zheng et al., GCN #30273; Blazek et al., GCN #30274; Kann et al., GCN #30275; Svinkin et al., GCN #30276; Xin et al., GCN #30277; Perley et al., GCN #30271, Shrestha et al., GCN #30280, Kumar et al. GCN #30286; Cunningham et al., GCN #30290; Romanov, GCN #30291; Hu et al., GCN #30293; Zhu et al., GCN #30294; Belkin et al., GCN #30299; Atteia, GCN #30301, Minaev et al., GCN #30304; Romanov & Lane, GCN #30305; Karpov et al., GCN #30308) with the SAO RAS 1-m telescope Zeiss-1000 + CCD-photometer. We obtained 12 x 300 sec. frames in Rc band on June 22 (22:26:19--23:45:27 UT), T_mid-T0 = 2.96283d. The OT is clearly detected in the stacked frame with the brightness R = 21.4 +/- 0.1 (based on nearby USNO-B1 stars).
GCN 30315 table
GRB_name GRB210619B
GCN_number 30315
Detection_method Swift Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 30315 SUBJECT: GRB 210619B: ASIM observation DATE: 21/06/25 07:18:32 GMT FROM: Martino Marisaldi at U of Bergen, Norway M. Marisaldi (University of Bergen), A. Mezentsev (University of Bergen), N. Østgaard (University of Bergen), V. Reglero (University of Valencia) and T. Neubert (DTU Space) report on behalf of the ASIM Team: At 23:59:27.928 UT on 19 June 2021, the Atmosphere-Space Interactions Monitor (ASIM) mission triggered on the long bright GRB 210619B (Swift detection: D’Avanzo et al., GCN Circ. 30261; GECAM detection: Zhao et al., GCN Circ. 30264; Fermi-LAT detection: Axelsson et al., GCN Circ. 30270; Konus-Wind detection: Svinkin et al., GCN Circ. 30276; Fermi GBM detection: Poolakkil et al., GCN Circ. 30279; CALET detection: Kawakubo et al., GCN Circ. 30284; SPI-ACS/INTEGRAL detection: Minaev et al., GCN Circ. 30304) Photon by photon data with <1 microsecond time resolution have been collected for a time interval of five seconds. As seen by the Modular X- and Gamma-Ray Sensor (MXGS) onboard ASIM the burst consists of a single emission episode. The emission is detected in the MXGS High Energy Detector (HED), sensitive in the range 0.3 to >30 MeV. The MXGS Low Energy Detector (LED), sensitive in the range 0.05 to 0.4 MeV, was not active at trigger time. ASIM is an ESA mission onboard the International Space Station dedicated to the observation of Terrestrial Gamma-ray Flashes (TGFs) and Transient Luminous Events (TLEs) operative since June 2018 (Neubert et al., Space Sci Rev (2019) 215:26 https://doi.org/10.1007/s11214-019-0592-z ). The payload includes the Modular X- and Gamma-Ray Sensor (MXGS) (Østgaard et al., Space Sci Rev (2019) 215:23 https://doi.org/10.1007/s11214-018-0573-7 ), and the the Modular Multispectral Imaging Array (MMIA) (Chanrion et al., Space Sci Rev (2019) 215:28 https://doi.org/10.1007/s11214-019-0593-y ). The ASIM Science Data Centre (ASDC) website is https://asdc.space.dtu.dk/
GCN 30320 table
GRB_name GRB210619B
GCN_number 30320
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30320 SUBJECT: GRB210619B: optical afterglow detection from Konkoly Observatory DATE: 21/06/25 21:54:22 GMT FROM: Jozsef Vinko at Konkoly Observator J. Vinko, L. Kriskovics, A. Pal, R. Szakats, K. Vida, Zs. Szabo, R. Konyves-Toth, M. Krezinger and K. Sarneczky (Konkoly Observatory, Hungary) report: We observed the field of GRB210619B (D'Avanzo et al.,GCN #30261, #30288, #30289; Jelinek et al., GCN #30263, #30281; Lipunov et al., GCN #30259; Zhao et al., GCN #30261; Kong et al., GCN #30265; Axelsson et al., #GCN 30270; de Ugarte Postigo et al., GCN #30272; Zheng et al., GCN #30273; Blazek et al., GCN #30274; Kann et al., GCN #30275; Svinkin et al., GCN #30276; Xin et al., GCN #30277; Perley et al., GCN #30271, Shrestha et al., GCN #30280, Kumar et al. GCN #30286; Cunningham et al., GCN #30290; Romanov, GCN #30291; Hu et al., GCN #30293; Zhu et al., GCN #30294; Belkin et al., GCN #30299; Atteia, GCN #30301, Minaev et al., GCN #30304; Romanov & Lane, GCN #30305; Karpov et al., GCN #30308; Moskvitin & Maslennikova, GCN #30309; Marisaldi et al., GCN #30315) with the RC80 robotic telescope at Piszkesteto Station of Konkoly Observatory on 2021 June 22 starting at 22:46:41.5 UT. A series of 5x300 sec frames were collected through Sloan r'- and i' bands. The optical afterglow was detected with the following magnitudes calibrated via nearby PS1 stars: Date UT-middle t-T0(hr) Exp(s) r'(mag) i'(mag) 2021-06-22 23:07:16 71.13 5x300 21.454 +/-0.333 20.089 +/-0.280 Follow-up observations on 2021-06-23 starting at 21:34:37.7 UT (3.90 days post-trigger) resulted in no detection down to limiting magnitudes of r'=22.14 and i'=21.98 mag.
GCN 30338 table
GRB_name GRB210619B
GCN_number 30338
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30338 SUBJECT: GRB 210619B: Deep CAHA 2.2m detection and late-time light curve behavior DATE: 21/06/28 10:29:27 GMT FROM: Alexander Kann at IAA-CSIC D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), M. Jelinek (ASU CAS Ondrejov), M. Blazek, C. Thoene, J. F. Agui Fernandez (all HETH/IAA-CSIC), and P. Minguez (CAHA) report: We re-observed the afterglow of GRB 210619B (D'Avanzo et al., GCN #30261) with CAFOS mounted at the 2.2m Calar Alto telescope (Almeria, Spain). Image depth was influenced by moonlight but conditions were good. We obtained 20 x 180 s images in r'. The afterglow is faintly detected in the stacked image. Against Pan-STARRS comparison stars, we derive r' = 22.56 +/- 0.16 mag at 6.12346 d after the trigger. Using selected data from GCN Circulars (Jelinek et al., GCN #30263, #30281; Pellegrin et al., GCN #30268; Perley, GCN #30271; Zheng & Filippenko, GCN #30273; Blazek et al., GCN #30274; Kann et al., GCN #30275; Xin et al., GCN #30277; D'Avanzo et al., GCN #30288; Moskvitin & Maslennikova, GCNs #303291, #30303, #30309; Romanov, GCN #30292; Hu et al., GCN #30293; Zhu et al., GCN #30294; Belkin et al., GCN #30299; Romanov & Lane, GCN #30305; Vinko et al., GCN #30320), we find the afterglow after 0.057 d can be fit by a smoothly broken power-law with a sharp break and parameters alpha_1 = 0.742 +/- 0.013, alpha_2 = 1.221 +/- 0.045, and break time t_b = 0.465 +/- 0.048 d (40136 +/- 4108 s). This fully confirms the steepening decay reported by Jelinek et al., GCN #30281; Kumar et al., GCN #30286. Note that the best fit of the X-ray light curve at the time finds alpha_1 = 0.978 +0.012 -0.019, alpha_2 = 1.50 +/- 0.035, t_b = 0.152 +0.015 -0.024 d (13100 +1300 -2100 s). However, the early decay (alpha_0 = 0.773 +0.087 -0.141, up to 500 s) is very similar to the optical decay we find from ~5000 s onward to the (optical) break. We note that the post-break decay slope would be extremely shallow if this were actually a jet break, but no deviation from this decay is seen until ~6 d.
GCN 30343 table
GRB_name GRB210619B
GCN_number 30343
Detection_method CALET
Circular_text TITLE: GCN CIRCULAR NUMBER: 30343 SUBJECT: GRB 210619B: Sayan observatory 1.6-m telescope observations DATE: 21/06/29 20:14:37 GMT FROM: Rodion Burenin at IKI, Moscow I. Zaznobin, R. Burenin, A. Lutovinov (IKI), E. Klunko, M. Eselevich (ISTP SB RAS) report: The field of GRB 210619B detected by Swift (D'Avanzo et al. GCN 30261), GECAM (Zhao et al. GCN 30264), CALET (Kawakubo et al. GCNC 30284), SRG/ART-XC (Levin et al. GCNC 30283), Fermi-LAT (Axelsson et al. GCNC 30270), Konus-Wind (Svinkin et al. GCN 30276) and Fermi/GBM (Poolakkil et al. GCNC 30279) was observed with the Sayan observatory 1.6-m telescope AZT-33IK, using a CCD photometer, starting at 2021/06/20 17:58 UT, i.e. approximately 18 hours after the burst. We obtained 12x60 s images in each g,r,i,z SDSS filter. The OT is clearly detected in every frame, with the following magnitudes: g = 20.26 +- 0.06 r = 19.51 +- 0.08 i = 19.08 +- 0.06 z = 18.69 +- 0.07
GCN 30361 table
GRB_name GRB210619B
GCN_number 30361
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 30361 SUBJECT: GRB 210619B: JCMT SCUBA-2 sub-mm observations DATE: 21/07/03 08:59:09 GMT FROM: Ian Smith at Rice U I.A. Smith (Rice U.), D.A. Perley (LJMU), and N.R. Tanvir (U. of Leicester) report: We observed the Swift UVOT location of GRB 210619B (D'Avanzo et al., GCN Circ. 30261) using the SCUBA-2 sub-millimeter continuum camera on the James Clerk Maxwell Telescope. Observations totaling 2.1 hours were obtained on UT 2021-06-20 and 2021-06-21 in average and poor weather conditions respectively. No counterpart was detected in the individual or combined maps. Combining all the data, the RMS background noise was 1.61 mJy/beam at 850 microns and 27.9 mJy/beam at 450 microns; the mid-point of the run was 1.07 days after the burst trigger. We thank Patrice Smith, Mark Rawlings, Harriet Parsons, and the JCMT staff for the prompt support of these observations that were taken under project M21AP020.
GCN 30386 table
GRB_name GRB210619B
GCN_number 30386
Detection_method Optical
ra 319.7181°
decl 33.8504°
Circular_text TITLE: GCN CIRCULAR NUMBER: 30386 SUBJECT: GRB 210619B: ALMA detection DATE: 21/07/06 02:19:43 GMT FROM: Tanmoy Laskar at U of Bath T. Laskar (University of Bath), K. D. Alexander (Northwestern), E. Berger (Harvard), W. Fong (Northwestern), R. Margutti (Northwestern), C. G. Mundell (University of Bath), and P. Schady (University of Bath) report on behalf of a larger collaboration: "We observed GRB 210619B (D'Avanzo et al. GCN 30261) with the Atacama Large Millimeter/Submillimeter Array (ALMA) at 97.5 GHz beginning on 2021 June 25 06:53:48 UT (5.29 days after the burst). ALMA observations of this burst were delayed due to a major snowstorm at the array. Preliminary analysis reveals a mm source with flux density of ~ 0.1 mJy at position: RA (J2000) = 21:18:52.349 (+/- 0.002) Dec (J2000) = +33:51:01.40 (+/- 0.04) consistent with the X-ray position (Beardmore et al. GCN 30267) and optical position (D'Avanzo et al., GCN 30261; Kuin et al. GCN 30278). We thank the JAO staff, AoD, P2G, and the entire ALMA team for their help with these observations."
GCN 30791 table
GRB_name GRB210619B
GCN_number 30791
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 30791 SUBJECT: GRB 210619B: Maidanak and Assy optical observations, broken power law parametrization DATE: 21/09/09 21:25:26 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Pozanenko (IKI), O. Burhonov (UBAI), V. Kim (FAI, HSE), M. Krugov (FAI), N. Pankov (HSE), Sh. Ehgamberdiev (UBAI), report on behalf of IKI-GRB-FuN: We observed the field of GRB 210619B (D'Avanzo et al. GCN 30261) with AZT-22 telescope of Maidanak Observatory and AZT-20 telescope of Assy-Turgen observatory. The optical afterglow (D'Avanzo et al. GCN 30261; Jelinek et al., GCN 30263; Kong, GCN 30265; Pellegrin et al., GCN 30268; Perley, GCN 30271; Zheng and Filippenko, GCN 30273; Blazek et al., GCN 30274; Kann et al., GCN 30275; Xin et al., GCN 30277; Kiun et al., GCN 30278; Shrestha et al., GCN 30280; Jelkinek et al., GCN 30281; Kumar et al., GCN 30286; D'Avanzo et al., GCN 30288; Moskvitin and Maslennikova, GCN 303291; Romanov, GCN 30292; Hu et al., GCN 30293; Zhu et al., GCN 30294; Belkin et al., GCN 30299; Moskvitin and Maslennikova, GCN 30303; Romanov and Lane, GCN 30305; Moskvitin and Maslennikova, GCN 30309; Vinko et al., GCN 30320; Kann et al., GCN 30338; Zaznobin et al., GCN 30343) is clearly detected on the most of stacked images. Preliminary photometry of the afterglow of some of observations is following. Date UT start t-T0 Filter Exp. OT UL(3sigma) Telescope (mid, days) (s) 2021-06-20 19:02:53 0.79963 R 8*300 19.47 0.06 23.0 AZT-22 2021-06-21 19:53:41 1.85019 R 12*300 20.43 0.05 23.2 AZT-22 2021-06-22 17:15:29 2.74206 r 75*60 21.82 0.26 22.6 AZT-20 2021-06-22 18:35:45 2.79606 R 12*300 21.21 0.09 23.1 AZT-22 2021-06-26 20:15:18 6.86520 R 20*180 22.55 0.24 23.2 AZT-22 2021-07-02 20:16:53 12.86630 R 12*300 23.5 0.3 23.5 AZT-22 2021-07-08 19:16:40 18.83003 r 76*60 n/d n/d 23.2 AZT-20 2021-07-18 19:50:46 28.84816 R 12*300 n/d n/d 23.9 AZT-22 Photometry is based on the USNO-B1.0 and PanSTARRS-PS1 nearby stars. USNO-B1.0_id R2 I 1238-0493928 15.08 14.33 1238-0494511 15.67 15.03 1238-0493842 17.53 17.36 1238-0493787 16.81 16.12 PanSTARRS-PS1 RA DEC r 21:18:52.24182 +33:49:14.6348 15.2925 21:18:45.71408 +33:50:40.3319 18.1642 Using our data and those published in the GCN circulars cited above we plot a light curve which an be found at http://grb.rssi.ru/GRB210619B/GRB210619B_LC_all.png Using only Maidanak data after 0.7 days, it was found that the light curve can be fitted by a single power law with the index alpha = -1.48 +/-0.04. Using early data published in GCNs we can describe the LC by a broken power law with parameters of alpha = -0.72+/-0.01, beta = -1.52 +/-0.04, and break time of 0.57+/-0.12. The fitted LC can be found at http://grb.rssi.ru/GRB210619B/GRB210619B_AZT22_LC.png It confirms the steeping decay suggested by Jelinek et al., GCN 30281, Kumar et al., GCN 30286. The power-law index before the break is approximately the same as that obtained by Kann et al., GCN 30338 and Oganesyan et al., arXiv:2109.00010, while the power law index after the break is steeper and coincides with XRT afterglow power law index. We also not detected any influence of host galaxy on afterglow light curve, and after late time observations we can estimate brightness of the host galaxy R > 23.9.