GRB200528A

This page lists all entries on GRB200528A in GRBweb

Summary Fermi GBM IPN Swift GCN 27831 GCN 27832 GCN 27833 GCN 27834 GCN 27835 GCN 27836 GCN 27837 GCN 27838 GCN 27839 GCN 27840 GCN 27841 GCN 27842 GCN 27849 GCN 27852 GCN 27855 GCN 27860 GCN 27883

Summary table
Variable Value Source
GRB_name_Fermi GRB200528436
T0 10:27:23 UTC GCN_circulars,Swift Det
ra 176.6375° Swift
decl 58.1926° Swift
pos_error 1.94e-04° Swift
T90 56.577 s Fermi_GBM
T90_error 0.362 s Fermi_GBM
T90_start 10:27:26.907 UTC Fermi_GBM
fluence 2.91e-05 erg/cm² Fermi_GBM
fluence_error 3.80e-08 erg/cm² Fermi_GBM
T100 60.484 s
GBM_located False
mjd 58997.43568287037 GCN_circulars,Swift Det
Fermi GBM table
GRB_name_Fermi GRB200528436
trigger_name bn200528436
ra 176.6442°
decl 58.1922°
pos_error 2.67e+00°
datum 2020-05-28
t_trigger 10:27:24.347 UTC
T90 56.577 s
T90_error 0.362 s
T90_start 10:27:26.907 UTC
fluence 2.91e-05 erg/cm²
fluence_error 3.80e-08 erg/cm²
flux_1024 2.72e+01 erg/cm²/s
flux_1024_error 4.24e-01 erg/cm²/s
flux_1024_time 3.33e+01 erg/cm²/s
flux_64 3.41e+01 erg/cm²/s
flux_64_error 1.96e+00 erg/cm²/s
IPN table
GRB_name GRB200528A
ra 176.6375°
decl 58.1500°
pos_error 5.00e-02°
Swift table
GRB_name GRB200528A
t_trigger 10:27:23 UTC
ra 176.6375°
decl 58.1926°
pos_error 1.94e-04°
T90 58.7 s
fluence 1.80e-05 erg/cm²
GCN 27831 table
GRB_name GRB200528A
GCN_number 27831
Detection_method Fermi GBM final loc
t_trigger 10:27:24 UTC
ra 169.2000°
decl 60.2000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 27831 SUBJECT: GRB 200528A: Fermi GBM Final Real-time Localization DATE: 20/05/28 10:37:56 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 10:27:24 UT on 28 May 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200528A (trigger 612354449.346938 / 200528436). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 169.2, Dec = 60.2 (J2000 degrees, equivalent to J2000 11h 16m, 60d 12'), with a statistical uncertainty of 1.0 degrees. The angle from the Fermi LAT boresight is 19.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_skymap_all_bn200528436.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_healpix_all_bn200528436.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_lc_medres34_bn200528436.gif
GCN 27832 table
GRB_name GRB200528A
GCN_number 27832
Detection_method Swift Det
t_trigger 10:27:23 UTC
ra 176.6370°
decl 58.1470°
Circular_text TITLE: GCN CIRCULAR NUMBER: 27832 SUBJECT: GRB 200528A: Swift detection of a burst DATE: 20/05/28 10:39:36 GMT FROM: Kim Page at U.of Leicester E. Ambrosi (INAF-IASFPA), V. D'Elia (SSDC), P. A. Evans (U Leicester), J.D. Gropp (PSU), N. J. Klingler (PSU), H. A. Krimm (NSF), F. E. Marshall (NASA/GSFC) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team: At 10:27:23 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200528A (trigger=974827). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 176.637, +58.147 which is RA(J2000) = 11h 46m 33s Dec(J2000) = +58d 08' 50" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 60 sec. The peak count rate was ~19000 counts/sec (15-350 keV), at ~33 sec after the trigger. The XRT began observing the field at 10:28:33.9 UT, 70.2 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 176.6438, 58.1921 which is equivalent to: RA(J2000) = 11h 46m 34.51s Dec(J2000) = +58d 11' 31.6" with an uncertainty of 5.2 arcseconds (radius, 90% containment). This location is 162 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 0.1 s image was 4.08e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 80 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01. Burst Advocate for this burst is E. Ambrosi (elena.ambrosi 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 27833 table
GRB_name GRB200528A
GCN_number 27833
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27833 SUBJECT: GRB 200528A: Potential host galaxy in PanSTARRS, SDSS and WISE DATE: 20/05/28 11:19:38 GMT FROM: Alexander Kann at IAA-CSIC A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), and D. A. Kann (HETH/IAA-CSIC) report: Within the XRT error circle of GRB 200528A (Fermi GBM team, GCN #27831; Ambrosi et al., GCN #27832), a bright, extended object is detected, at position (J2000, from SDSS): RA = 176.64297 Dec. = 58.19313 It is found to have (from SDSS): u' = 22.28 +/-0.42 mag; g' = 21.46 +/- 0.075 mag; r' = 20.45 +/- 0.047 mag; i' = 20.13 +/- 0.052 mag; z' = 19.88 +/- 0.147 mag. It is also detected in PanSTARRS and WISE with W1 = 16.7 +/- 0.1 mag. The photometric redshift in SDSS is given as z = 0.380 +/- 0.0792. We suggest this galaxy to be the host galaxy of GRB 200528A. The early non-detection in UVOT indicates this might be an optically dark GRB, as the X-ray light curve is very bright early on. The X-ray column density is unknown so far (Ambrosi et al., GCN #27832) but likely to be high. Confirmation or rejection awaits a refined XRT position once data are obtainable in PC mode.
GCN 27834 table
GRB_name GRB200528A
GCN_number 27834
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 27834 SUBJECT: GRB 200528A: MITSuME Akeno optical upper limits DATE: 20/05/28 13:14:26 GMT FROM: Adachi Ryo at Tokyo Institute of Tech R. Adachi, R. Hosokawa, K. L. Murata, M. Niwano, F. Ogawa, N. Nakamura, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 200528A (Fermi GBM team, GCN #27831; Ambrosi et al., GCN #27832) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescopes of Akeno Observatory in Japan. The observation started on 10:28:31.87 UT. The first 40 images were heavily affected by twilight and bad weather at Akeno Observatory. We checked single images and combined images. We did not find any new point sources within the Swift/XRT error circle (Ambrosi et al., GCN #27832) in all three bands. Also, we did not detect the potential host galaxy (de Ugarte Postigo et al., GCN #27833) due to shallow upper limits of our observation. We obtained the 5-sigma limits as follows. T0+[min] MID-UT T-EXP[sec] 5-sigma limits ------------------------------------------------------------------------------------------------ 36.7 11:28:34 1020 g'>18.9, Rc>18.3, Ic>17.4 ------------------------------------------------------------------------------------------------ T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used the UCAC4 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., submitted; https://github.com/MNiwano/Eclair).
GCN 27835 table
GRB_name GRB200528A
GCN_number 27835
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 27835 SUBJECT: Swift GRB 200528A: Global MASTER-Net observations report DATE: 20/05/28 13:24:40 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) was pointed to the Swift GRB 200528A ( E. Ambrosi et al., GCN 27832) errorbox 9786 sec after notice time and 9804 sec after trigger time at 2020-05-28 13:10:47 UT, with upper limit up to 16.7 mag. Observations started at twilight. The observations began at zenith distance = 22 deg. The sun altitude is -12.3 deg. The galactic latitude b = 57 deg., longitude l = 138 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1368165 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 9894 | MASTER-Amur | C | 180 | 16.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
GCN 27836 table
GRB_name GRB200528A
GCN_number 27836
Detection_method Swift-XRT Det
ra 176.6374°
decl 58.1926°
Circular_text TITLE: GCN CIRCULAR NUMBER: 27836 SUBJECT: GRB 200528A: Enhanced Swift-XRT position DATE: 20/05/28 14:43:12 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 910 s of XRT Photon Counting mode data and 3 UVOT images for GRB 200528A, 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 = 176.63744, +58.19257 which is equivalent to: RA (J2000): 11h 46m 32.99s Dec (J2000): +58d 11' 33.3" with an uncertainty of 1.8 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 27837 table
GRB_name GRB200528A
GCN_number 27837
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27837 SUBJECT: GRB 200528A: Nanshan/NEXT optical upper limit DATE: 20/05/28 16:59:24 GMT FROM: Dong Xu at NAOC/CAS Z.P. Zhu, S.Y. Fu, X. Liu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), X. Zhang, J.Z. Liu (XAO) report: We observed the field of GRB 2005528A (Ambrosi et al., GCN 27832) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We obtained 5x120s frames in the Sloan r-band, starting at 15:55:41 UT on 2020-05-28, i.e., 5.47 hr after the burst. No optical source is detected in our stacked image at the enhanced XRT position (Evans et al., GCN 27836), down to a limiting magnitude of r~20.1, calibrated with nearby SDSS field.
GCN 27838 table
GRB_name GRB200528A
GCN_number 27838
Detection_method Fermi GBM Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 27838 SUBJECT: GRB 200528A: 1.3m DFOT Optical Upper Limits DATE: 20/05/28 17:52:58 GMT FROM: Amit Kumar at ARIES, India A. Kumar (ARIES), S. B. Pandey (ARIES), R. Gupta (ARIES), K. Misra (ARIES), A. Aryan (ARIES), A. Ghosh (ARIES), and Dimple (ARIES) report: We carried out observation of Fermi GBM detected GRB 200528A (GCN 27831, Ambrosi et al., GCN 27832) with the 1.3m Devasthal Fast Optical Telescope (DFOT) at Devasthal observatory of Aryabhatta Research Institute of observational sciencES (ARIES), India. The observation was started on 2020-05-28T15:37:05 UTC. We observed a series of 4 x 300s exposures using the Bessell I filter covering Swift XRT enhanced position (Evans et al., 27836). We do not detect any new optical source within the Swift XRT enhanced error circle in individual as well as in the stacked image (Adachi et al., GCN 27834, Lipunov et al., GCN 27835 and Zhu et al., GCN 27837). We obtained the 3-sigma upper limit as follows: T_start-T0(hrs) Start Date (UTC) End Date (UTC) Filter Limit (mag) ----------------------------------------------------------------------------------------------- 5.161 2020-05-28T15:37:05 2020-05-28T15:58:42 I 20.2 +- 0.2 Photometry is done based on the USNO-B1.0 catalog. This magnitude is not corrected for Galactic extinction in the direction of the GRB.
GCN 27839 table
GRB_name GRB200528A
GCN_number 27839
Detection_method Swift-BAT Det
ra 176.6370°
decl 58.1850°
Circular_text TITLE: GCN CIRCULAR NUMBER: 27839 SUBJECT: GRB 200528A: Swift-BAT refined analysis DATE: 20/05/28 21:45:22 GMT FROM: Hans Krimm at NSF/NASA-GSFC S. D. Barthelmy (GSFC), E. Ambrosi (INAF-IASFPA), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (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-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 200528A (trigger #974827) (Ambrosi, et al., GCN Circ. 27832). The BAT ground-calculated position is RA, Dec = 176.637, 58.185 deg which is RA(J2000) = 11h 46m 32.8s Dec(J2000) = +58d 11' 07.3" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 62%. The mask-weighted light curve shows a multi-peaked structure rising just before T0, peaking around T+35 sec and decaying to background by T+120 sec. T90 (15-350 keV) is 58.7 +- 1.4 sec (estimated error including systematics). The time-averaged spectrum from T-1.02 to T+112.88 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.62 +- 0.14, and Epeak of 40.1 +- 5.5 keV (chi squared 25.28 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.8 +- 0.0 x 10^-5 erg/cm2 and the 1-sec peak flux measured from T+33.82 sec in the 15-150 keV band is 17.5 +- 0.5 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.14 +- 0.03 (chi squared 69.65 for 57 d.o.f.). 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/974827/BA/
GCN 27840 table
GRB_name GRB200528A
GCN_number 27840
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 27840 SUBJECT: GRB 200528A: Swift/UVOT Upper Limits DATE: 20/05/28 22:25:58 GMT FROM: Frank Marshall at Swift/UVOT F. E. Marshall (NASA/GSFC) and E. Ambrosi (INAF-IASFPA) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 200528A 81 s after the BAT trigger (Ambrosi et al., GCN Circ. 27832). No optical afterglow consistent with the enhanced XRT position (Evans et al. GCN Circ. 27836) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 81 231 147 >21.1 u 293 305 12 >18.7 v 5743 5942 197 >18.8 b 5127 5327 169 >20.7 uvw2 5538 5738 197 >21.0 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).
GCN 27841 table
GRB_name GRB200528A
GCN_number 27841
Detection_method Fermi GBM Det
t_trigger 10:27:24.350 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 27841 SUBJECT: GRB 200528A: Fermi GBM Observation DATE: 20/05/28 23:28:45 GMT FROM: Cori Fletcher at USRA C. Fletcher (USRA), A. von Kienlin and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 10:27:24.35 UT on 28 May 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200528A (trigger 612354449 / 200528436) which was also detected by the Swift/BAT (Ambrosi et al. 2020, GCN 27832) The Fermi GBM Final Real-time Localization (GCN 27831) is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 16 degrees. The GBM light curve shows multiple peaks with a duration (T90) of about 56 s (50-300 keV). The time-averaged spectrum from T0+2.05 s to T0+59.4 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.39 +/- 0.02 and the cutoff energy, parameterized as Epeak, is 55.5 +/- 0.8 keV. The event fluence (10-1000 keV) in this time interval is (2.54 +/- 0.02)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+33.3 s in the 10-1000 keV band is 27.2 +/- 0.4 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 27842 table
GRB_name GRB200528A
GCN_number 27842
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27842 SUBJECT: GRB 200528A: NOT optical upper limits DATE: 20/05/29 00:02:50 GMT FROM: Daniele B Malesani at DTU Space D. B. Malesani (DTU Space), J. P. U. Fynbo (DAWN/NBI), L. Izzo (DARK/NBI), D. Xu (NAOC/CAS), T. Pursimo (NOT), report on behalf of a larger collaboration: We observed the field of GRB 200528A (Ambrosi et al., GCN 27832) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations were carried out under variable, thin clouds. After stacking the good images in each filter, no afterglow is visible in either band within the XRT position (Evans et al., GCN 27836). At mean epochs May 28.926 and 28.927 UT (11.78 and 11.80 hr after the GRB, respectively), we derive limiting magnitudes r > 23.5 and z > 22 AB (calibrated against nearby stars in the Pan-STARRS catalog). We note that the galaxy visible in the archival surveys and noted by de Ugarte Postigo & Kann (GCN 27833) is about 10.6 arcsec away of the UVOT-enhanced XRT position (1.5" error; Evans et al., GCN 27836), and is thus likely unrelated to the GRB.
GCN 27849 table
GRB_name GRB200528A
GCN_number 27849
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27849 SUBJECT: GRB 200528A: Assy optical upper limit DATE: 20/05/29 08:09:05 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), V. Kim (AFIF, Pulkovo Observatory), A. Pozanenko (IKI), M. Krugov (AFIF), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of larger GRB IKI FuN collaboration: We observed GRB 200528A (Fermi GBM Team GCN 27831; Ambrosi et al., GCN 27832) with AZT-20 1.5 m telescope of Assy-Turgen observatory starting on May., 28 (UT) 16:16:12. We do not detect any sources in the Swift-XRT extended position (Evans et al., GCN 27836). Preliminary photometry of the field is following. Date UT start t-T0 Filter Exp. OT Err. UL (3sigma) (mid, days) (s) 2020-05-28 16:16:12 0.26777 r(AB) 54*60 n/d n/d 22.4 The photometry is based on the nearby stars of SDSS catalog SDSS-DR12_id r J114613.33+581329.5 19.455 J114632.90+581307.2 19.190 J114549.81+581044.3 19.004 J114600.53+580839.6 16.985
GCN 27852 table
GRB_name GRB200528A
GCN_number 27852
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 27852 SUBJECT: GRB 200528A: Swift-XRT refined Analysis DATE: 20/05/29 10:39:04 GMT FROM: Phil Evans at U of Leicester M. Perri (ASDC), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), B. Sbarufatti (PSU), D.N. Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester) and E. Ambrosi report on behalf of the Swift-XRT team: We have analysed 5.7 ks of XRT data for GRB 200528A (Ambrosi et al. GCN Circ. 27832), from 73 s to 50.9 ks after the BAT trigger. The data comprise 226 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 27836). The late-time light curve (from T0+5.1 ks) can be modelled with a power-law decay with a decay index of alpha=0.97 (+/-0.07). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.30 (+/-0.05). The best-fitting absorption column is 3.63 (+0.19, -0.18) x 10^21 cm^-2, in excess of the Galactic value of 1.2 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.24 (+0.16, -0.15) and a best-fitting absorption column of 3.8 (+0.7, -0.6) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (6.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.8 (+0.7, -0.6) x 10^21 cm^-2 Galactic foreground: 1.2 x 10^20 cm^-2 Excess significance: 9.8 sigma Photon index: 2.24 (+0.16, -0.15) If the light curve continues to decay with a power-law decay index of 0.97, the count rate at T+24 hours will be 0.041 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.4 x 10^-12 (2.5 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00974827. This circular is an official product of the Swift-XRT team.
GCN 27855 table
GRB_name GRB200528A
GCN_number 27855
Detection_method CALET
Circular_text TITLE: GCN CIRCULAR NUMBER: 27855 SUBJECT: GRB 200528A: CALET Gamma-Ray Burst Monitor detection DATE: 20/05/29 12:29:14 GMT FROM: Valentin Pal'shin at AGU V. Pal'shin, A. Yoshida, T. Sakamoto, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, S. Torii (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 soft GRB 200528A (Swift detection: Ambrosi et al., GCN Circ. 27832, Barthelmy et al., GCN Circ. 27839; Fermi GBM observation: Fletcher and Meegan, GCN Circ. 27841; https://gcn.gsfc.nasa.gov/other/200528A.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 10:27:27.087 UTC on 28 May 2020. The burst signal was seen by all CGBM detectors. Because of a problem in one of the ground alert processing script, the GCN notice was not distributed automatically for this event. The burst light curve shows a multi-peaked structure which starts at T-4.5 sec, peaks at T+30.8 sec and ends at T+35.1 sec. The T90 and T50 durations measured by the SGM data are 36.6 +- 3.2 sec and 27.9 +- 4.0 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1274696855/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN 27860 table
GRB_name GRB200528A
GCN_number 27860
Detection_method Swift Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 27860 SUBJECT: GRB 200528A: CAHA Upper Limit DATE: 20/05/29 22:44:01 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. C. Thoene, J. F. Agui Fernandez (all HETH/IAA-CSIC), and I. Hermelo (CAHA) report: We observed the XRT error circle (Evans et al., GCN #27836) of the bright GRB 200528A (Swift detection: Ambrosi et al., GCN #27832; Fermi GBM detection: The Fermi GBM team, GCN #27831) with the 2.2m telescope at CAHA (Almeria, Spain), equipped with the CAFOS detector. We obtained 21 x 180 s exposures in the Ic band under adverse observing conditions (moonlight, bad seeing and transparency). At the enhanced XRT position, we detect no source (but would have preferred to). We derive a 3 sigma limiting magnitude of Ic > 23.5 mag (Vega) at 0.440865 days after the GRB, calibrated against SDSS standard stars transformed to the Ic band following Lupton (2005). This limit is comparable to those achieved by NOT about an hour later (Malesani et al., GCN #27842).
GCN 27883 table
GRB_name GRB200528A
GCN_number 27883
Detection_method Konus-Wind Det
t_trigger 10:27:55.256 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 27883 SUBJECT: Konus-Wind observation of GRB200528A DATE: 20/06/02 09:06:41 GMT FROM: Anastasia Tsvetkova at Ioffe Institute A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Lysenko, A. Ridnaia and T. Cline on behalf of the Konus-Wind team, report: The long-duration, soft-spectrum GRB200528A (Swift detection: Ambrosi et al., GCN 27832; Barthelmy et al., GCN 27839; Fermi GBM Observation: Fletcher, von Kienlin & Meegan, GCN 27841; CALET Gamma-Ray Burst Monitor detection: Pal'shin et al., GCN 27855) triggered Konus-Wind at T0=37675.256 s UT (10:27:55.256). The burst light curve shows a complex structure which starts at ~T0-33.8 s, with a total duration of~60.0 s, and comprises two double-peaked emission episodes. The emission is seen up to ~1 MeV. As observed by Konus-Wind, the burst had a fluence of 2.12(-0.07,+0.07)x10^-5 erg/cm2, and a 64-ms peak energy flux, measured from T0+1.696 s, of 2.38(-0.35,+0.35)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+33.024 s) is best fit in the 20 keV - 1 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.41(-0.14,+0.14), and Ep = 64(-5,+5) keV (chi2 = 50/60 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.89 (chi2 = 49/59 dof). The spectrum near the peak count rate (measured from T0+0.256 to T0+8.448 s) is best fit in the 20 keV - 1 MeV range by the power law with exponential cutoff model with alpha = -1.14(-0.15,+0.16), and Ep = 75(-4,+5) keV (chi2 = 52/60 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -3.03 (chi2 = 51/59 dof). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB200528_T37675/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.