GRB230427A

This page lists all entries on GRB230427A in GRBweb

Summary IPN Swift GCN 33687 GCN 33688 GCN 33690 GCN 33693 GCN 33695 GCN 33696 GCN 33697 GCN 33698 GCN 33699 GCN 33703 GCN 33704 GCN 33705 GCN 33706 GCN 33707 GCN 33708 GCN 33710 GCN 33711 GCN 33712 GCN 33722

Summary table
Variable Value Source
T0 10:31:52 UTC GCN_circulars,Swift Det
ra 153.3127° Swift
decl 48.2040° Swift
pos_error 9.58e-05° Swift
redshift 0.1412 GCN_circulars,Other
GBM_located False
mjd 60061.438796296294 GCN_circulars,Swift Det
IPN table
GRB_name GRB230427A
ra 153.3250°
decl 48.1833°
pos_error 5.00e-02°
Swift table
GRB_name GRB230427A
t_trigger 10:31:52 UTC
ra 153.3127°
decl 48.2040°
pos_error 9.58e-05°
GCN 33687 table
GRB_name GRB230427A
GCN_number 33687
Detection_method Swift Det
t_trigger 10:31:52 UTC
ra 153.3240°
decl 48.1800°
Circular_text TITLE: GCN CIRCULAR NUMBER: 33687 SUBJECT: GRB 230427A: Swift detection of a burst with an optical counterpart DATE: 23/04/27 10:51:55 GMT FROM: K.L. Page at U Leicester E. Troja (UToV), P. A. Evans (U Leicester), R. A. J. Eyles-Ferris (U Leicester), C. Gronwall (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team: At 10:31:52 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 230427A (trigger=1165948). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 153.324, +48.180 which is RA(J2000) = 10h 13m 18s Dec(J2000) = +48d 10' 48" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). No BAT light-curve is available at this time. The XRT began observing the field at 10:33:25.9 UT, 94.0 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 153.31199, 48.20404 which is equivalent to: RA(J2000) = 10h 13m 14.88s Dec(J2000) = +48d 12' 14.6" with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 91 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (8.35 x 10^19 cm^-2, Willingale et al. 2013), with an excess column of 3.5 (+2.81/-2.63) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 98 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 10:13:15.05 = 153.31270 DEC(J2000) = +48:12:14.4 = 48.20400 with a 90%-confidence error radius of about 0.74 arc sec. This position is 1.4 arc sec. from the center of the XRT error circle. The estimated magnitude is 20.31 with a 1-sigma error of about 0.20. No correction has been made for the expected extinction corresponding to E(B-V) of 0.007. Burst Advocate for this burst is E. Troja (nora.gsfc AT gmail.com). 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 33688 table
GRB_name GRB230427A
GCN_number 33688
Detection_method Swift-XRT Det
ra 153.3132°
decl 48.2039°
Circular_text TITLE: GCN CIRCULAR NUMBER: 33688 SUBJECT: GRB 230427A: Enhanced Swift-XRT position DATE: 23/04/27 13:41:28 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 1112 s of XRT Photon Counting mode data and 2 UVOT images for GRB 230427A, 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 = 153.31316, +48.20393 which is equivalent to: RA (J2000): 10h 13m 15.16s Dec (J2000): +48d 12' 14.2" with an uncertainty of 2.4 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 33690 table
GRB_name GRB230427A
GCN_number 33690
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 33690 SUBJECT: GRB 230427A: MITSuME Akeno optical upper limits DATE: 23/04/27 15:34:00 GMT FROM: Ichiro Takahashi at Tokyo Tech I. Takahashi, S. Hayatsu, N. Higuchi, M. Sasada, R. Hosokawa, S. Sato, M. Niwano, H. Seki, H. Takei, Y. Yatsu (Tokyo Tech), K. L. Murata (Kyoto U) and N. Kawai (Riken) report on behalf of the MITSuME collaboration: We observed the field of GRB 230427A (Troja et al. GCN Circular #33687, Beardmore et al. GCN Circular #33688) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope Akeno. The observation started at 2023-04-27 10:33:23 UT (91 seconds after the Swift/BAT trigger). We stacked the images with good conditions. We did not detect any uncatalogued sources within the error region (Troja et al. GCN Circular #33687). We obtained the 5-sigma limits of the stacked images as follows. T0+[sec] | MID-UT | T-EXP[sec] | 5-sigma limits ------------------------------------------------------------------------------------------------ 263 | 2023-04-27 10:36:15 | 160.0 | g'>17.8, Rc>17.4, Ic>17.0 753 | 2023-04-27 10:44:25 | 540.0 | g'>18.7, Rc>18.7, Ic>18.2 2391 | 2023-04-27 11:11:43 | 2220.0 | g'>19.6, Rc>19.4, Ic>19.0 ------------------------------------------------------------------------------------------------ T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used the PS1 catalog for flux calibration. The magnitudes are expressed in the AB system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages 4-24; https://github.com/MNiwano/Eclaire).
GCN 33693 table
GRB_name GRB230427A
GCN_number 33693
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 33693 SUBJECT: GRB 230427A: AKO Upper Limit DATE: 23/04/27 19:23:20 GMT FROM: Mohammad Odeh at Al Khatim Observatory M44 Mohammad Odeh of Al-Khatim Observatory (AKO) operated by the International Astronomical Center, in Abu Dhabi, UAE. As a follow-up for the GRB 230427A detected by Swift (GCN 33687), we observed the field of the GRB with our 0.35m f/7.7 robotic telescope. The observation was done on 27 April 2023 from 16:06:55 to 16:13:01 (UT), 5.7 hours after the GRB trigger. We obtained multiple 180-sec exposures in Ic filter. We did not detect any afterglow within XRT localization. This is consistent with the report of (Takahashi et al., GCN 33690) and (Lipunov et al., GCN 33692). The following upper limit was calculated using Atlas catalogue as a reference: ----------------------------------------------------------------------------- JD (mid), T_mid-T0(hrs), Exposure (sec), Filter, Lim_mag ----------------------------------------------------------------------------- 2460062.174630, 5.7, 3 x 180 (stacked), Ic, > 19.0 ----------------------------------------------------------------------------- These magnitudes are not corrected for galactic extinction.
GCN 33695 table
GRB_name GRB230427A
GCN_number 33695
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 33695 SUBJECT: GRB 230427A: BOOTES-5/JGT afterglow detection DATE: 23/04/27 22:44:56 GMT FROM: Youdong HU at IAA-CSIC Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado, I. Perez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy (IAA-CSIC), D. Hiriart and W. H. Lee (UNAM), C. J. Perez del Pulgar (UMA) and I. M. Carrasco-Garcia (SMA) and I. H. Park (SKKU), on behalf of a larger collaboration, report: Following the detection of GRB 230427A by Swift (Troja et al. GCNC 33687), the BOOTES-5/JGT 0.6m robotic telescope at observatorio Astronomico Nacional in San Pedro Martir (Mexico) automatically observed the GRB location starting on Apr. 27, 10:35:34 UT (~ 282 s after trigger). A series of images in clear filter were gathered. A new optical transient was found within the enhanced Swift/XRT position (Beardmore et al. GCNC 33688) for which we measure a magnitude of 20.6 +- 0.2 on the co-added 10 s x 54 image, which is consistent with the detection of Swfit/UVOT (Troja et al. GCNC 33687). We thank the staff at Observatorio Astronomico Nacional in San Pedro Martir for their excellent support.
GCN 33696 table
GRB_name GRB230427A
GCN_number 33696
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 33696 SUBJECT: GRB 230427A : OHP/T193 optical upper limit DATE: 23/04/27 23:52:46 GMT FROM: Damien Turpin at CEA-Saclay D. Turpin (CEA Paris-Saclay), C. Adami (LAM), B. Schneider (MIT), S. Basa (LAM), E. Le Floc'h, D. Turpin, D. Götz (CEA Paris-Saclay), S. D. Vergani (GEPI, Obs. de Paris), report on behalf of a larger collaboration: We observed the field of GRB 230427A (Troja et al., GCN 33687) using the T193cm telescope at Observatoire de Haute-Provence (France) equipped with the MISTRAL spectro-imager. 18 exposures were obtained in the r-band (16x300s + 2x60s) from 2023 27 April 20:36:47 UT to 2023 27 April 22:59:06 UT (mid time ~11.27h after trigger). In the combined frame, we do not detect any source at the UVOT position reported by Troja et al., GCN 33687 and the enhanced XRT position (Beardmore et al., GCN 33688) down to the following 3-sigma limit: r > 22.3 mag (AB) The photometric calibration was performed using nearby stars from the PanSTARRS catalog and the magnitude is not corrected for Galactic extinction. We acknowledge the excellent support from Observatoire de Haute-Provence, in particular Jean Balcaen.
GCN 33697 table
GRB_name GRB230427A
GCN_number 33697
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 33697 SUBJECT: GRB 230427A: GMG upper limit DATE: 23/04/28 03:50:39 GMT FROM: Jirong Mao at Yunnan Obs J. Mao, H.-C. Feng, and J.-M. Bai (YNAO) report: We observed the field of GRB 230427A (Troja et al. GCN 33687) by the GMG telescope in Yunnan observatories. The observation began from UT 14:52:28 April 27, 2023, about 4.3 hours from the trigger. We could not observe the optical afterglow down to a magnitude limit of R~20.6.
GCN 33698 table
GRB_name GRB230427A
GCN_number 33698
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 33698 SUBJECT: GRB 230427A: Bassano Bresciano Observatory upper limit DATE: 23/04/28 08:19:17 GMT FROM: Ulisse Quadri at Bassano Bresciano Obs U.Quadri and L.Strabla (Bassano Bresciano Astronomical Observatory), in a large collaboration with: M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy), K. Kalinowski (Aarhus University, Department of Physics and Astronomy), B. De Simone (Universita' degli Studi Di Salerno) report: We imaged the field of GRB 230427A detected by SWIFT(trigger 1165948) with the robotic telescope of (IAU station 565) Bassano Bresciano Observatory, Italy. Member of: AAVSO - American Association of Variable Star Observers. UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili. GAC - Gruppo Astrofili Cremonesi. The observations started 8.72 hour after the GRB trigger, at the end of twilight, with our Newton telescope D=250 mm F/D=4.8. Weather conditions were good. We co-added 2 series of 25 exposures of 60 sec each. Start T0+ End T0+ Rlim 8.72 hour 9.63 hour 19.5 We did not found any optical counterpart in the error box of the XRTcandidate. Troja et al., GCN 33687 Magnitudes were estimated with the USNO-B1.0 cat. and are not corrected for galactic dust extinction. Reference: http://www.osservatoriobassano.org/GRB.asp The message may be cited.
GCN 33699 table
GRB_name GRB230427A
GCN_number 33699
Detection_method Optical
ra 153.3132°
decl 48.2039°
Circular_text TITLE: GCN CIRCULAR NUMBER: 33699 SUBJECT: GRB 230427A: GIT optical upper limit DATE: 23/04/28 09:16:24 GMT FROM: Harsh Kumar at Indian Inst of Tech,Bombay T. Roychowdhury(IITB), V. Swain (IITB), A. Suresh (IITB), H. Kumar(IITB), D. Raman(IITB), Kaysang (IAO), V. Bhalerao(IITB), G. C. Anupama(IIA), S. Barway(IIA) report on behalf of the GIT team: We observed GRB 230427A detected by Swift-BAT (Troja et al., GCN 33687) with 0.7m GROWTH-India Telescope (GIT). The observations started at 14:20:43 UT on 2023-04-27, 3.8 hours after the Swift-BAT trigger. We obtained 10 images of 300-sec exposures in the r' filter and 5 images of 300-sec exposures in the i', z' and g' filters. We did not detect any new source in our stacked image within the 2.4 arcsec circle, around R.A.= 10h 13m 15.16s, DEC.=+48d 12' 14.2". The obtained upper limits follow as: ——————————————————————————————————————————————————————————————————— ————————————— JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Lim_mag (5-sigma) | —————————————————————————————————————————————————————————————————— —————————————— 2460062.1148169 | 4.22 | 10 x 300 (stacked) | r' | > 21.70 | 2460062.1433660 | 4.91 | 5 x 300 (stacked) | i' | > 20.76 | 2460062.1604599 | 5.31 | 5 x 300 (stacked) | z' | > 19.42 | 2460062.1775733 | 5.73 | 5 x 300 (stacked) | g' | > 21.35 | ——————————————————————————————————————————————————————————————————— ————————————— Our results are consistent with the upper limit reported by AKO (M. Odeh, GCN #33693), BOOTES-5/JGT (Y.-D. Hu et al., GCN #33695), OHP/T193 (D. Turpin et al., GCN #33696), GMG (J. Mao et al., GCN #33697) and Bassano Bresciano Observatory (U.Quadri et al., GCN #33698). The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction. The GROWTH India Telescope (GIT, Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
GCN 33703 table
GRB_name GRB230427A
GCN_number 33703
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 33703 SUBJECT: GRB 230427A: Swift-XRT refined Analysis DATE: 23/04/28 12:54:32 GMT FROM: Phil Evans at U of Leicester A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), J. D. Gropp (PSU) report on behalf of the Swift-XRT team: We have analysed 4.5 ks of XRT data for GRB 230427A, from 80 s to 75.0 ks after the BAT trigger. The data comprise 7 s in Windowed Timing (WT) mode (taken while Swift was slewing), with the remainder in Photon Counting (PC) mode. The light curve can be modelled with a power-law decay with a decay index of alpha=1.21 (+0.12, -0.11). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.94 (+0.30, -0.26). The best-fitting absorption column is 4.0 (+6.6, -3.2) x 10^20 cm^-2, consistent with the Galactic value of 8.4 x 10^19 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (3.6 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 4.0 (+6.6, -3.2) x 10^20 cm^-2 Galactic foreground: 8.4 x 10^19 cm^-2 Excess significance: <1.6 sigma Photon index: 1.94 (+0.30, -0.26) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01165948. This circular is an official product of the Swift-XRT team.
GCN 33704 table
GRB_name GRB230427A
GCN_number 33704
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 33704 SUBJECT: GRB 230427A: OSIRIS+/GTC observations DATE: 23/04/28 15:05:51 GMT FROM: J. F. Agui Fernandez at IAA-CSIC J. F. Agui Fernandez (IAA-CSIC), A. de Ugarte Postigo (OCA), C. C. Thoene (ASU-CAS), Fabricio Perez, Alvaro Tejero and A. L. Cabrera Lavers (GTC, IAC) report: We observed the afterglow of GRB 230427A at ~ 11.3 hours after burst (Page et al. GCN 33687; Takahashi et al. GCN 33690; Hu et al. GCN 33695; Tohuvavohu et al. 33703) with OSIRIS+ at the 10.4m GTC telescope, at the Roque de los Muchachos Observatory (La Palma, Spain). Observations consisted of 3x1200 s spectroscopy with grism R1000B, covering the spectral range between 3700 and 7800 AA under good observing conditions. From the acquisition image we detect a source at the GRB location and we measure a magnitude of r ~ 24.2 compared to PanSTARRS field stars. We detect a faint trace at GRB location above ~3950A which set a limit for the redshift of z < 3.3.
GCN 33705 table
GRB_name GRB230427A
GCN_number 33705
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 33705 SUBJECT: GRB 230427A: Osservatorio Astronomico Nastro verde upper limit DATE: 23/04/28 15:20:54 GMT FROM: Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy - MPC Code C82 Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy in a large collaboration with: M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy), K. Kalinowski (Aarhus University, Department of Physics and Astronomy), B. De Simone (Universita' degli Studi Di Salerno) report: We image the field of GRB 230427A detected by SWIFT(trigger 1165948) with telescope of Nastro Verde Observatory - Sorrento (Naples), Italy. Member of: AAVSO - American Association of Variable Star Observers. UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili. AstroCampania Associazione The observations started at 19:04 UT of 2023/04/27, after 8,30 hours after the GRB trigger, at the end of twilight with principal telescope SC 0.35 f/10 with focal reduced + CCD Sbig ST10 XME I took 32 image of 120 sec each. All images are unfiltered, calibrated with masterdark and masterflat,stacked with Tycho Tracker software We have not detected any clearly visible sources, up to 20th magnitude with lightly hazy skies and lunar disturbance Start T0+ End T0+ Rlim 19:04:53 UT 20:22:52 UT 20 We did not found any optical counterpart in the error box of the XRTcandidate. Troja et al., GCN 33687 Magnitudes were estimated with the Gaia DR2 cat. and are not corrected for galactic dust extinction. The message may be cited.
GCN 33706 table
GRB_name GRB230427A
GCN_number 33706
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 33706 SUBJECT: GRB 230427A: Nanshan/HMT optical upper limit DATE: 23/04/28 15:38:03 GMT FROM: Dong Xu at NAOC/CAS S.Q. Jiang, S.Y. Fu, X. Liu, T.H. Lu, D. Xu (NAOC), Z.P. Zhu (NAOC, HUST), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report: We observed the field of GRB 230427A detected by Swift (Troja et al., GCN 33687) using the HMT-0.5m telescope located at Nanshan, Xinjiang, China. Observations started at 14:50:24 UT on 2023-04-27, i.e., 4.3 hr after the Swift/BAT trigger, and 30x60 s unfiltered frames were obtained. No optical source is detected in our stacked image at the UVOT position (Troja et al., GCN 33687), down to a 3-sigma limiting magnitude m(r) > 21.1 mag (AB) at 4.7 hr post-burst, calibrated with the nearby PanSTAR field in the Sloan r-filter. The magnitude is not corrected for Galactic extinction.
GCN 33707 table
GRB_name GRB230427A
GCN_number 33707
Detection_method Other
redshift 0.1412
Circular_text TITLE: GCN CIRCULAR NUMBER: 33707 SUBJECT: GRB 230427A: OHP/T193 spectroscopy observations of WISEA J101316.01+481158.7 DATE: 23/04/28 15:40:52 GMT FROM: Benjamin Schneider at MIT C. Adami, M. Garnichey, F. Michel (LAM), B. Schneider (MIT), S. Basa (LAM), S. D. Vergani (GEPI, Obs. de Paris), D. Turpin, D. Götz, E. Le Floc'h (CEA Paris-Saclay), report on behalf of a larger collaboration: We re-observed the field of GRB 230427A (Troja et al., GCN 33687) using the T193cm telescope at Observatoire de Haute-Provence (France) equipped with the MISTRAL spectro-imager. This time, we targeted in spectroscopy the galaxy close to the GRB line of sight: WISEA J101316.01+481158.7, at r'SDSS(PSF) = 19.6 (AB). Two exposures of 900s were obtained in the blue configuration (4200A-8000A) from 2023 28 April 00:25:02 UT to 2023 28 April 00:55:59 UT. The wavelength calibration was performed using the MISTRAL calibration lamp, exposed just after the science observation. Data were reduced using the ASPIRED package (https://github.com/cylammarco/ASPIRED) configured for MISTRAL data. In the combined frame, we clearly detect the [NII]@6548A, Halpha, [NII]@6583A, and [SII]@6718A. Halpha is the dominant line of the spectrum. Based on these lines, we inferred a redshift of z = 0.1524 +/- 0.0005, in good agreement with the SDSS photometric redshift of z = 0.13 +/- 0.03. The GRB is at an offset of ~18 arcsec from the WISEA J101316.01+481158.7 center. At the redshift of this galaxy, the burst would have a projected offset of ~48 kpc and a probability of chance coincidence of ~0.16, which is not commonly observed for the long GRB population. For this reason, this object is probably not the host galaxy of GRB 230427A. We acknowledge the excellent support from Observatoire de Haute-Provence, in particular Jean Balcaen.
GCN 33708 table
GRB_name GRB230427A
GCN_number 33708
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 33708 SUBJECT: GRB 230427A: Gaoyazi/GOT optical upper limit DATE: 23/04/28 15:42:19 GMT FROM: Dong Xu at NAOC/CAS S.Y. Fu, S.Q. Jiang, X. Liu, T.H. Lu, D Xu (NAOC), Z.P. Zhu (NAOC, HUST), S.W. Luo, M.M. Yang, Z. K. Feng (GYZO, NAOC) report: We observed the field of GRB 230427A detected by Swift (Troja et al., GCN 33687) with the GOT-0.5m telescope located at Gaoyazi, Xinjiang, China. Observations started at 16:34:35 UT on 2023-04-27, i.e., 6.05 hr after the Swift/BAT trigger, 5 x 90 s and 10 x 120 s images were obtained in the Sloan r filter. No optical source is detected in our stacked image at the UVOT position (Troja et al,. GCN 33687), down to a 3-sigma limiting magnitude r > 20.4 (AB) at 6.32 hr post-burst, calibrated with nearby PanSTARRS stars. The magnitude is not corrected for Galactic extinction.
GCN 33710 table
GRB_name GRB230427A
GCN_number 33710
Detection_method Swift-UVOT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 33710 SUBJECT: GRB 230427A: Swift/UVOT Detection DATE: 23/04/28 18:03:41 GMT FROM: N. Klingler at NASA-GSFC/UMBC/CRESST II N. J. Klingler (GSFC/UMBC/CRESTII) and E. Troja (UToV) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 230427A 98 s after the BAT trigger (Troja et al., GCN Circ. 33687). A source consistent with the XRT position (Evans et al. 2023, GCN Circ. 33688) is detected in the initial UVOT exposures. 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 98 248 147 20.19 +/- 0.15 v 586 4999 255 >19.3 b 512 1158 58 >19.6 u 256 854 265 >20.5 w1 810 5404 231 >20.0 m2 5004 5204 197 >19.6 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.007 in the direction of the burst (Schlegel et al. 1998).
GCN 33711 table
GRB_name GRB230427A
GCN_number 33711
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 33711 SUBJECT: GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit DATE: 23/04/28 21:28:46 GMT FROM: Alexei Pozanenko at IKI, Moscow I. Reva (FAP), A. S. Moskvitin (SAO RAS), O. A. Maslennikova (SAO RAS), R. Ya. Inasaridze (AbAO), A. Volnova (IKI), A. Pozanenko (IKI), N. Pankov (HSE), S. Belkin (IKI) report on behalf of GRB IKI FuN: We observed the field of Swift GRB 230427A (Troja et al., GCN 33687) in R-filter on 2023-04-27 starting (UT) 15:09:59 with with Zeiss-1000 telescope of TSHAO observatory, (UT) 17:21:56 with Zeiss-1000 telescope of SAO RAS, (UT) 21:56:16 with AS-32 telescope of Abastumani observatory. We do not detect the optical counterpart of GRB 230427A (Troja et al., GCN 33687; Hu et al., GCN 33695; Agui Fernandez et al., GCN 33704; Klingler et al., GCN 33710). Preliminary photometry of stacked images is following Date UT start t-T0 Exp. Filter OT Err. UL(3sigma) Obs. (mid, days) (s) 2023-04-27 15:09:59 0.22388 37*120 R n/d n/d 21.8 TSAHO 2023-04-27 17:21:56 0.30117 4*300 R n/d n/d 21.4 SAO RAS 2023-04-27 21:56:16 0.51140 104*60 R n/d n/d 21.0 AbAO The photometry is based on nearby USNO-B1.0 stars. USNO-B1.0 R2 1381-0248742 15.71 1381-0240666 16.93 1381-0240629 16.83
GCN 33712 table
GRB_name GRB230427A
GCN_number 33712
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 33712 SUBJECT: GRB 230427A: NOT optical upper limit DATE: 23/04/29 15:45:11 GMT FROM: Dong Xu at NAOC/CAS Z.P. Zhu (NAOC, HUST), D. B. Malesani (Radboud Univ. and DAWN/NBI), X. Liu, D. Xu (NAOC), report on behalf of a larger collaboration: We observed the field of GRB 230427A detected by Swift (Troja et al., GCN 33687) using the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations started at 23:06:58 UT on 2023-04-27, i.e., ~12.6 hr after the Swift/BAT trigger, and 3x300 s Sloan r-filter images and 5x200 s Sloan z-filter images were obtained, respectively. No new source is detected in our stacked images at the Swift/UVOT position (Troja et al., GCN 33687), and preliminary photometric results are as follows: T_mid-T0 (hr) Filter Upper_Limit (3-sigma) 12.7 r >23.5 13.0 z >22.5 calibrated with the nearby Pan-STARRS field and not corrected for Galactic extinction.
GCN 33722 table
GRB_name GRB230427A
GCN_number 33722
Detection_method Swift-BAT Det
ra 153.3390°
decl 48.2310°
Circular_text TITLE: GCN CIRCULAR NUMBER: 33722 SUBJECT: GRB 230427A: Swift-BAT refined analysis DATE: 23/05/03 22:26:28 GMT FROM: Sibasish Laha at GSFC M. Stamatikos (OSU), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU), (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 230427A (trigger #1165948) (Troja et al., GCN Circ. 33687). The BAT ground-calculated position is RA, Dec = 153.339, 48.231 deg which is RA(J2000) = 10h 13m 21.5s Dec(J2000) = +48d 13' 52.3" with an uncertainty of 3.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 86%. The BAT light curve showed a complex structure with a duration of about 20 sec. T90 (15-350 keV) is 4.00 +- 1.41 sec (estimated error including systematics). The time-averaged spectrum from T-0.17 to T+3.83 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.36 +- 0.47. The fluence in the 15-150 keV band is 9.5 +- 2.9 x 10^-08 erg/cm2. The 1-sec peak photon flux measured from T-0.17 sec in the 15-150 keV band is 0.7 +- 0.2 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/1165948/BA/