//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27756 SUBJECT: GRB 200519A: Swift detection of a burst with an optical afterglow DATE: 20/05/19 11:42:49 GMT FROM: Kim Page at U.of Leicester B. Sbarufatti (PSU), S. B. Cenko (GSFC), C. Gronwall (PSU), J.D. Gropp (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team: At 11:20:23 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200519A (trigger=973140). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 255.334, -30.380 which is RA(J2000) = 17h 01m 20s Dec(J2000) = -30d 22' 47" 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 80 sec. The peak count rate was ~37000 counts/sec (15-350 keV), at ~23 sec after the trigger. The XRT began observing the field at 11:21:13.3 UT, 49.6 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 255.3327, -30.3782 which is equivalent to: RA(J2000) = 17h 01m 19.85s Dec(J2000) = -30d 22' 41.5" with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 7.6 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 1.36e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 57 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 17:01:20.00 = 255.33335 DEC(J2000) = -30:22:40.9 = -30.37803 with a 90%-confidence error radius of about 0.61 arc sec. This position is 2.1 arc sec. from the center of the XRT error circle. The estimated magnitude is 15.38 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.47. Burst Advocate for this burst is B. Sbarufatti (bxs60 AT psu.edu). 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/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27757 SUBJECT: GRB 200519A: iTelescope optical afterglow detection DATE: 20/05/19 16:37:18 GMT FROM: Albert Kong at NTHU A.K.H. Kong (NTHU, Taiwan) reports We observed the field of GRB 200519A (Sbarufatti et al. GCN 27756) with the T31 0.5m telescope of iTelescope.Net in Siding Spring, Australia. The observation was done with a luminance filter (400-700 nm) beginning at 2020-05-19 15:07:45 UT (about 3.8 hours after the trigger) for 300 sec. The optical afterglow (Sbarufatti et al. GCN 27756) was detected with an estimated magnitude of 19.3+/-0.8 by calibrating with the USNO UCAC5 catalogue. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27759 SUBJECT: GRB 200519A: LCO Optical Afterglow Detection DATE: 20/05/19 17:04:42 GMT FROM: Robert Strausbaugh at U. of the Virgin Islands R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration: We observed Swift GRB 200519A (Sbarufatti et al., GCN 27756) with the LCO 1-m Sinistro instrument at the Siding Spring Observatory Australia site, on May 9, from 12:39 to 13:02 UT (corresponding to 1.05 to 1.38 hours from the GRB trigger time) with the Bessel R and I filters. We performed a series of 5x120s exposures in R and I. We detect an optical source in stacked images at the UVOT afterglow candidate position position. Using the USNO-B.1 catalog as reference, we calculate the following magnitudes: R = 17.07 +/- 0.02 I = 16.69 +/- 0.02 These magnitudes are not corrected for galactic extinction. R.S. is funded by NSF AST grant #1831682 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27760 SUBJECT: GRB 200519A: BOOTES-3/YA optical counterpart observations DATE: 20/05/19 21:41:56 GMT FROM: Youdong HU at IAA-CSIC Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado (IAA-CSIC), I. Carrasco and C. Perez del Pulgar (Univ. de Malaga), M. D. Caballero-Garcia (ASU-CAS, CZ) and R. Querel (NIWA), on behalf of a larger collaboration, report: The 60cm BOOTES-3/YA robotic telescope at NIWA Lauder in Otago (New Zealand) automatically responded to the Swift trigger of GRB 200519A (Sbarufatti et al. GCNC 27756). The first image (clear filter) were obatined starting at 11:20:57 UT (~ 34 s after trigger). At the position reported by Swift/UVOT (Sbarufatti et al. GCNC 27756), we found the optical counterpart with a magnitude of 14.96+-0.12 mag in the 1s exposure image whose median time at 52s that also reported by iTelescope (Kong et al. GCNC 27757) and LCO (Strausbaugh et al. GCNC 27759), which calibrated with nearby stars in USNO-B 1.0 catalog. Further analysis is ongoing. We thank the staff at NIWA for its excellent support. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27761 SUBJECT: GRB 200519A: Enhanced Swift-XRT position DATE: 20/05/19 22:12:54 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 832 s of XRT Photon Counting mode data and 3 UVOT images for GRB 200519A, 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 = 255.33318, -30.37824 which is equivalent to: RA (J2000): 17h 01m 19.96s Dec (J2000): -30d 22' 41.7" 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27763 SUBJECT: GRB 200519A: Swift-XRT refined Analysis DATE: 20/05/19 23:42:47 GMT FROM: Phil Evans at U of Leicester D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , J. D. Gropp (PSU), J.A. Kennea (PSU) and B. Sbarufatti report on behalf of the Swift-XRT team: We have analysed 8.2 ks of XRT data for GRB 200519A (Sbarufatti et al. GCN Circ. 27756), from 42 s to 35.4 ks after the BAT trigger. The data comprise 970 s in Windowed Timing (WT) mode (the first 5 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 27761). The light curve can be modelled with a power-law decay with a decay index of alpha=1.16 (+/-0.05). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.902 (+/-0.029). The best-fitting absorption column is 4.35 (+0.17, -0.16) x 10^21 cm^-2, in excess of the Galactic value of 3.3 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.75 (+/-0.08) and a best-fitting absorption column of 4.7 (+/-0.5) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.7 x 10^-11 (6.6 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 4.7 (+/-0.5) x 10^21 cm^-2 Galactic foreground: 3.3 x 10^21 cm^-2 Excess significance: 4.4 sigma Photon index: 1.75 (+/-0.08) If the light curve continues to decay with a power-law decay index of 1.16, the count rate at T+24 hours will be 0.11 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.1 x 10^-12 (7.1 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/00973140. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27764 SUBJECT: GRB 200519A: 1.3m DFOT Optical Afterglow Detection DATE: 20/05/20 01:58:43 GMT FROM: Amit Kumar at ARIES, India A. Kumar (ARIES), S. B. Pandey (ARIES), K. Chand (ARIES), A. Aryan (ARIES), R. Gupta (ARIES), A. Ghosh (ARIES), Dimple (ARIES), and K. Misra (ARIES) report: We observed the optical afterglow of the Swift detected GRB 200519A (GCN 27756, GCN 27761 and GCN 27763) with the 1.3m Devsthal Fast Optical Telescope (DFOT) at Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital (India), from 2020-05-19T19:17:27 to 2020-05-19T22:01:38 UTC. We observed 11 frames each of 300 seconds in Bessell R filter, whereas, a serious of 7x300 seconds exposure in Bessell I filter. In the stacked images, we clearly detected the optical afterglow of GRB 200519A in both Bessell R and I filters within the Swift XRT enhanced error circle (Osborne et al. GCN 27761). The estimated magnitudes are consistent with optical detections by Kong et al. GCN 27757, Strausbaugh et al. GCN 27759, and Hu et al. 27760. The observed magnitudes are as follows: T_start-T0 (hours) Start Date (UTC) Filter Magnitudes (mag) --------------------------------------------------------------------------------------------------------------- 7.95 2020-05-19T19:17:27 R 19.4 +- 0.1 9.98 2020-05-19T21:19:27 I 18.2 +- 0.1 Photometry is done based on the USNO-B1.0 catalog. The quoted magnitudes are not corrected for Galactic extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27765 SUBJECT: Swift GRB 200519A: Global MASTER-Net observations report DATE: 20/05/20 05:38:25 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 200519A ( B. Sbarufatti et al., GCN 27756) errorbox 23275 sec after notice time and 23295 sec after trigger time at 2020-05-19 17:48:38 UT, with upper limit up to 17.0 mag. The observations began at zenith distance = 75 deg. The sun altitude is -25.5 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB 200519A errorbox 46397 sec after notice time and 46416 sec after trigger time at 2020-05-20 00:14:00 UT, with upper limit up to 16.6 mag. The observations began at zenith distance = 69 deg. The sun altitude is -31.7 deg. The galactic latitude b = 7 deg., longitude l = 354 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1360465 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 23385 | MASTER-SAAO | C | 180 | 16.9 | 23385 | MASTER-SAAO | C | 180 | 16.2 | 24012 | MASTER-SAAO | C | 180 | 17.0 | 24012 | MASTER-SAAO | C | 180 | 16.6 | 46507 | MASTER-OAFA | C | 180 | 16.6 | 47353 | MASTER-OAFA | C | 180 | 16.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27766 SUBJECT: GRB 200519A: AstroSat CZTI detection DATE: 20/05/20 09:38:42 GMT FROM: Soumya Gupta at IUCAA/ASTROSAT S. Gupta, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (IUCAA/TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data showed the detection of a long GRB 200519A, which was also detected by Swift (Sbarufatti B. et al., GCN #27756), iTelescope (Kong A.et al., GCN # 27757), LCO (Strausbaugh R. et al., GCN # 27759), BOOTES-3/YA (Hu Y. et al., GCN # 27760), 1.3m DFOT (Kumar A. et al., GCN # 27764) and Global MASTER-Net (Lipunov V. et al., GCN # 27765). The source was clearly detected in the 40-200 keV energy range. Of the ~80-second duration reported by Swift/BAT, CZTI detected only the brightest segment peaking at 2020-05-19 11:20:46.500 UT. The measured peak count rate associated with the burst is 983 +/- 39 cts/s above the background in the combined data of four quadrants, with a total of 3616 +/- 17 cts. The local mean background count rate was 519 +/- 1 cts/s. Using cumulative rates, we measure a T90 of 8.46 +/- 0.05 s. It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed a single peak of emission peaking at 2020-05-19 11:20:46.000 UT. The measured peak count rate is 2339 +/- 62 cts/s above the background in the combined Veto data of four quadrants, with a total of 8499 +/- 21 cts. The local mean background count rate was 1541 +/- 1 cts/s. We measure a T90 of 8.64 +/- 0.02 s from the cumulative Veto light curve. CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27767 SUBJECT: GRB 200519A: GROWTH-India optical follow-up DATE: 20/05/20 16:32:17 GMT FROM: Harsh Kumar at Indian Inst of Tech,Bombay H. Kumar, V. Bhalerao(IITB), G. C. Anupama, S. Barway, J. Stanzin (IIA) report on behalf of the GROWTH-India collaboration: We followed up GRB200519A (R. Sbarufatti et al., GCN 27756, A. Kong et al., GCN 27757, R. Strausbaugh et al., GCN 27759, Y. Hu et al., GCN 27760, A Kumar et al., GCN 27764) with 0.7m GROWTH-India telescope. We obtained 600-sec exposures in SDSS g, r, i filters starting at UT 20-05-19T17:11:06 (~5.85 hrs after the burst). We obtained the following magnitudes with PSF photometry, calibrated against PanSTARRs PS1 data release (Flewelling et al., 2018). ------------------------------------------------------------------ JD(Start) | T-T0(hrs) | Filter | Mag | ------------------------------------------------------------------ 2458989.216 | 5.85 | g | 19.926 +/- 0.09 2458989.321 | 8.36 | g | 20.514 +/- 0.09 2458989.354 | 9.16 | g | 20.779 +/- 0.13 2458989.281 | 7.41 | r | 19.359 +/- 0.07 2458989.305 | 7.98 | r | 19.505 +/- 0.06 2458989.329 | 8.56 | r | 19.788 +/- 0.06 2458989.361 | 9.33 | r | 19.891 +/- 0.08 2458989.265 | 7.02 | i | 19.529 +/- 0.12 2458989.313 | 8.17 | i | 19.984 +/- 0.14 2458989.369 | 9.52 | i | 20.206 +/- 0.18 2458989.392 | 10.07| i | 20.583 +/- 0.26 ------------------------------------------------------------------ We found that the source is fading with a power-law of 1.65 +/- 0.28 in g band, 2.36 +/- 0.4 using in r band and 2.37 +/- 0.33 in i band observations. The magnitudes are 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). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27769 SUBJECT: GRB 200519A: Swift/UVOT Detection DATE: 20/05/20 19:09:27 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and B. Sbarufatti (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 200519A 58 s after the BAT trigger (Sbarufatti et al., GCN Circ. 27756). A source consistent with the XRT position (Sbarufatti et al. GCN Circ. 27756) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 17:01:20.01 = 255.33337 (deg.) Dec (J2000) = -30:22:41.1 = -30.37808 (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 58 208 147 15.43 +/- 0.02 v 599 619 20 16.30 +/- 0.16 b 525 545 19 17.13 +/- 0.13 u 270 519 246 16.27 +/- 0.04 w1 648 840 39 17.46 +/- 0.25 w2 747 766 19 >17.5 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.47 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27770 SUBJECT: GRB 200519A: Insight-HXMT/HE detection DATE: 20/05/21 02:10:25 GMT FROM: Shuo Xiao at IHEP GRB 200519A: Insight-HXMT/HE detection S. Xiao, Y. G. Zheng, C. Cai, Y. F. Du, W. C. Xue, Q. Luo, Q. B. Yi, Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong,C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: At 2020-05-19T11:20:23.73 (T0), Insight-HXMT/HE detected GRB 200519A (trigger ID: HEB200519472) in a routine search of the data, which also triggered Swift/BAT (GCN #27756). The Insight-HXMT/HE light curve mainly consists of multiple pulses with a duration (T90) of 8.97 s measured from T0+19.85 s. The 1-ms peak rate, measured from T0+23.18 s, is 1206 cnts/sec. The total counts from this burst is 4010 counts. URL_LC: http://twiki.ihep.ac.cn/twiki/viewfile/HXMT/GRBList?filename=HEB200519472_lc.jpg;rev=2 All measurements above are made with the CsI detectors operating in the normal mode with the energy range of about 80-800 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27771 SUBJECT: GRB 200519A: Swift-BAT refined analysis DATE: 20/05/21 03:38:57 GMT FROM: Amy Lien at GSFC M. Stamatikos (OSU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (PSU), 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 200519A (trigger #973140) (Sbarufatti et al., GCN Circ. 27756). The BAT ground-calculated position is RA, Dec = 255.319, -30.393 deg which is RA(J2000) = 17h 01m 16.6s Dec(J2000) = -30d 23' 35.6" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 99%. The mask-weighted light curve shows a multi-peaked structure that starts at ~T0 and ends at ~T+100 s. The three main peaks occur at ~T+1 s, ~T+24 s, and ~T+75 s, respectively. T90 (15-350 keV) is 71.88 +- 1.28 sec (estimated error including systematics). The time-averaged spectrum from T-0.45 to T+103.00 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.42 +- 0.03. The fluence in the 15-150 keV band is 1.2 +- 0.02 x 10^-05 erg/cm2. The 1-sec peak photon flux measured from T+23.53 sec in the 15-150 keV band is 20.6 +- 0.5 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/973140/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27772 SUBJECT: GRB 200519A: R-band follow-up from HCT DATE: 20/05/21 10:52:29 GMT FROM: Brajesh Kumar at Indian Inst. of Astrophysics Brajesh Kumar, Anirban Dutta, Avinash Singh, G. C. Anupama, D. K. Sahu and Pramod Kumar (IIA, Bengaluru) We observed the optical afterglow of GRB 200519A (Sbarufatti et al., GCN 27756) with the 2-m Himalayan Chandra Telescope (HCT) located at the Indian Astronomical Observatory, Hanle, India. The observations started on 2020-05-19 (20:10:35 UT) under good sky conditions and three consecutive frames (120, 240, and 240 sec) in Bessell R-band were obtained. The OT candidate (Kong et al., GCN 27757, Strausbaugh et al., GCN 27759, Hu et al., GCN 27760, Kumar et al., GCN 27764, Kumar et al. GCN 27767, Siegel & Sbarufatti, GCN 27769) is clearly detected in each frame. The preliminary photometry is performed relative to the USNO-B1.0 catalogue. The initial magnitude of the OT is 19.70 +- 0.10 (uncorrected for the galactic extinction). We thank the observing staff at IAO and CREST for helping with the observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27773 SUBJECT: GRB 200519A: CALET Gamma-Ray Burst Monitor detection DATE: 20/05/21 14:03:23 GMT FROM: Valentin Pal'shin at AGU P. S. Marrocchesi (U of Siena), A. Yoshida, T. Sakamoto, V. Pal'shin, 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), and the CALET collaboration: The Swift GRB 200519A (Swift detection: Sbarufatti et al., GCN Circ. 27756, Stamatikos et al., GCN Circ. 27771; AstroSat CZTI detection: Gupta et al., GCN Circ. 27766; Insight-HXMT/HE detection: GCN Circ. 27770; https://gcn.gsfc.nasa.gov/other/200519A.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 11:20:43.755 UTC on 19 May 2020 (trigger #1273922014: http://cgbm.calet.jp/cgbm_trigger/flight/1273922014/). The burst signal was seen mainly by the SGM detector. The source location was outside the FOV of the HXM detectors. The burst light curve shows a double-peaked pulse which starts at T-2.0 sec, peaks at T+4.4 sec and ends at T+5.9 sec. The T90 and T50 durations measured by the SGM data are 6.9 +- 1.5 sec and 3.3 +- 1.9 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1273922014/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.