GRB170428A

This page lists all entries on GRB170428A in GRBweb

Summary IPN Swift GCN 21042 GCN 21044 GCN 21045 GCN 21046 GCN 21047 GCN 21048 GCN 21049 GCN 21050 GCN 21051 GCN 21052 GCN 21053 GCN 21054 GCN 21055 GCN 21058 GCN 21059 GCN 21067 GCN 21942

Summary table
Variable Value Source
T0 9:13:38.719 UTC GCN_circulars,Konus-Wind Det
ra 330.0781° Swift
decl 26.9158° Swift
pos_error 2.98e-04° Swift
T90 0.2 s Swift
T90_start 9:13:42 UTC Swift
fluence 2.80e-07 erg/cm² Swift
redshift 0.4540
T100 3.481 s
GBM_located False
mjd 57871.384475914354 GCN_circulars,Konus-Wind Det
IPN table
GRB_name GRB170428A
ra 330.0625°
decl 26.9167°
pos_error 5.00e-02°
redshift 0.4540
Swift table
GRB_name GRB170428A
t_trigger 9:13:42 UTC
ra 330.0781°
decl 26.9158°
pos_error 2.98e-04°
T90 0.2 s
fluence 2.80e-07 erg/cm²
GCN 21042 table
GRB_name GRB170428A
GCN_number 21042
Detection_method Swift Det
t_trigger 9:13:42 UTC
ra 330.0630°
decl 26.9180°
Circular_text TITLE: GCN CIRCULAR NUMBER: 21042 SUBJECT: GRB 170428A: Swift detection of a short burst DATE: 17/04/28 09:38:15 GMT FROM: David Palmer at LANL A. P. Beardmore (U Leicester), N. P. M. Kuin (UCL-MSSL), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and R. L. C. Starling (U Leicester) report on behalf of the Swift Team: At 09:13:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170428A (trigger=750298). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 330.063, +26.918 which is RA(J2000) = 22h 00m 15s Dec(J2000) = +26d 55' 03" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peak structure with a duration of about 0.25 sec. The peak count rate was ~22000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 09:15:06.9 UT, 84.6 seconds after the BAT trigger. Swift then passed into the SAA, during which time no data are collected. No source was detected in 208 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 84 seconds with the U filter starting 866 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 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.06. Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). 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/too.html.)
GCN 21044 table
GRB_name GRB170428A
GCN_number 21044
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 21044 SUBJECT: GRB 170428A: MASTER-OAFA early optical observations DATE: 17/04/28 15:19:42 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) , National University of San Juan, Argentina H. Levato, C. Saffe Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, D.Kuvshinov, A.V.Krylov, I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk, O. Ershova Irkutsk State University V.Yurkov, Yu.Sergienko Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in OAFA was pointed to the GRB170428.38 17 sec after notice time and 31 sec after trigger time at 2017-04-28 09:14:14 UT. On our first (10s exposure) set we haven't found optical transient within SWIFT error-box (ra=330.062 dec=26.9172 r=0.05). The 5-sigma upper limit has been about 16.5 mag The observations made on zenit distance = 72 degrees, galaxy latitude b = -22 degree. The moon ( 5 % bright part) below the horizon (The altitude of the Moon is -49 degree ). The sun altitude is -24.2 degree. The object can be observed till sunrise at 2017-04-28 11:06:50 The message may be cited.
GCN 21045 table
GRB_name GRB170428A
GCN_number 21045
Detection_method Konus-Wind Det
t_trigger 9:13:38.719 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 21045 SUBJECT: Konus-Wind observation of GRB 170428A DATE: 17/04/28 18:30:50 GMT FROM: Dmitry Svinkin at Ioffe Institute A. Tsvetkova, S. Golenetskii, R. Aptekar, D. Frederiks, D. Svinkin, P. Oleynik, M. Ulanov, A. Lysenko, A.Kozlova, and T. Cline on behalf of the Konus-Wind team, report: The short-duration, bright GRB 170428A (Swift-BAT detection: Beardmore et al., GCN Circ. 21042) triggered Konus-Wind at T0=33218.719 s UT (09:13:38.719). The burst light curve shows a multipeaked structure which starts at ~T0-0.02 s and has a total duration of ~0.14 s. The emission is seen up to ~10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB170428_T33218/ As observed by Konus-Wind, the burst had a fluence of 4.20(-0.90,+0.91)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0+0.056 s, of 5.00(-1.52,+1.53)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+0.128 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.47(-0.21,+0.28), the high energy photon index beta = -2.46(-7.54,+0.52), the peak energy Ep = 982(-355,+394) keV (chi2 = 31/37 dof). Fitting this spectrum by a power law with exponential cutoff model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -0.53(-0.18,+0.21) and Ep = 1134(-268,+368) keV (chi2 = 33/38 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN 21046 table
GRB_name GRB170428A
GCN_number 21046
Detection_method Swift-BAT Det
ra 330.0510°
decl 26.9130°
Circular_text TITLE: GCN CIRCULAR NUMBER: 21046 SUBJECT: GRB 170428A: Swift-BAT refined analysis DATE: 17/04/28 21:04:52 GMT FROM: Hans Krimm at NSF/NASA-GSFC S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), 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-119 to T+303 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170428A (trigger #750298) (Beardmore, et al., GCN Circ. 21042). The BAT ground-calculated position is RA, Dec = 330.051, 26.913 deg which is RA(J2000) = 22h 00m 12.3s Dec(J2000) = +26d 54' 47.9" with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 62%. The mask-weighted light curve shows a complex of three peaks within a period from T+0.15 to T+0.35 sec. There is no sign of extended emission. T90 (15-350 keV) is 0.20 +- 0.07 sec (estimated error including systematics). The time-averaged spectrum from T+0.15 to T+0.45 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.76 +- 0.12. The fluence in the 15-150 keV band is 2.8 +- 0.2 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.20 sec in the 15-150 keV band is 2.8 +- 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/750298/BA/
GCN 21047 table
GRB_name GRB170428A
GCN_number 21047
Detection_method Swift-XRT Other
ra 330.0781°
decl 26.9158°
Circular_text TITLE: GCN CIRCULAR NUMBER: 21047 SUBJECT: GRB 170428A: Swift-XRT refined Analysis DATE: 17/04/28 21:19:32 GMT FROM: Andy Beardmore at U Leicester A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: We have analysed 4.2 ks of XRT data for GRB 170428A, from 697 s to 17.2 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. Using 1475 s of PC mode data and 2 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 330.07813, +26.91580 which is equivalent to: RA (J2000): 22h 00m 18.75s Dec(J2000): +26d 54' 56.9" with an uncertainty of 2.3 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=1.03 (+0.32, -0.29). If the light curve continues to decay with a power-law decay index of 1.03, the count rate at T+24 hours will be 7.5 x 10^-4 count s^-1 The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00750298. This circular is an official product of the Swift-XRT team.
GCN 21048 table
GRB_name GRB170428A
GCN_number 21048
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 21048 SUBJECT: GRB 170428A: Xinglong 2.16-m upper limit and host galaxy candidate DATE: 17/04/29 00:31:01 GMT FROM: Dong Xu at NAOC/CAS D. Xu (NAOC), Y. Qin (Geneva Obs.), Y. Zhao, J.J. Jia, H.X. Feng, Z.P. Zhu (NAOC), Y.D. Hu (IAA-CSIC), S. Feng, M.T. Ju (SHAO) report We observed the field of short GRB 170428A (Beardmore et al., GCN 21042) using the 2.16-m telescope located at Xinglong, Hebei, China. We obtained 6x300s R-band frames, starting at 19:23:21 UT on 2017-04-28 (i.e., 10.16 hr after the burst). No optical source is detected at the XRT position (Beardmore & Evans, GCN 21047) in the stacked R-band image, down to a limiting magnitude of m(R)>21.0. We note that in the SDSS and Pan-STARRS archival data there already exists a singe source within the XRT error circle, seemingly extended in the northeast - southwest direction. It is localised at R.A (J2000) = 22:00:18.687 Dec. (J2000) = +26:54:56.51 with a brightness of m(r)~22.2 mag, and thus might be the host galaxy of this short burst.
GCN 21049 table
GRB_name GRB170428A
GCN_number 21049
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 21049 SUBJECT: GRB 170428A: Swift/UVOT Upper Limits DATE: 17/04/29 00:40:35 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (UCL-MSSL) and A. P. Beardmore (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 170428A 740 s after the BAT trigger (Beardmore et al., GCN Circ. 21042). No optical afterglow consistent with the XRT position (Beardmore et al., GCN Circ. 21047) 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 initial exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag v 740 16576 1101 >20.0 b 838 10823 1101 >21.0 u 813 5412 299 >19.5 w1 789 5207 216 >19.5 m2 764 17481 1102 >20.1 w2 4392 11731 1082 >20.0 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the burst (Schlegel et al. 1998).
GCN 21050 table
GRB_name GRB170428A
GCN_number 21050
Detection_method Optical
ra 330.0782°
decl 26.9158°
Circular_text TITLE: GCN CIRCULAR NUMBER: 21050 SUBJECT: GRB 170428A: GROND detection of the afterglow DATE: 17/04/29 01:15:09 GMT FROM: Jan Bolmer at MPE/Garching Jan Bolmer (ESO, Chile), Helmut Steinle and Patricia Schady (both MPE Garching) report: We observed the field of GRB 170428A (trigger=750298, Beardmore et al., GCN #21042) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at the ESO La Silla Observatory (Chile). Observations started at 09:57 UT on 2017-04-28, 43 min after the GRB trigger, and they were performed at an average seeing of 1.2'' and at an average airmass of 2.2. We detect an uncatalogued source within the XRT error circle reported by Beardmore et al. (GCN #21047) at the position of RA, Dec = 330.07823, 26.91584, which is equivalent to: RA (J2000): 22h 00m 18.78s Dec (J2000): +26d 54' 57.0'' with an uncertainty of 0.3 arcsec. Based on combined images with 17 min of total integration time in g'r'i'z' and 19 min in JHK at a mid-time of 10:15 UT on 2017-04-28, this source has the following preliminary magnitudes (all in the AB system): g' = 21.4 +/- 0.1 mag r' = 21.3 +/- 0.1 mag i' = 21.1 +/- 0.1 mag z' = 21.1 +/- 0.1 mag J = 20.7 +/- 0.2 mag H = 20.9 +/- 0.4 mag K > 20.0 mag The given magnitudes are derived based on calibrating the images against SDSS in the optical and 2MASS field stars in the NIR bands. They are not corrected for the Galactic foreground extinction corresponding to a reddening of E_(B-V)= 0.05 in the direction of the burst (Schlafly & Finkbeiner 2011). As noted by Xu et al. (GCN #21048), there already exists a single source with a brightness of r ~ 22.2 mag, presumably the host galaxy, in the SDSS and Pan-STARRS archival data. We therefore likely observed the NIR/optical afterglow of the short GRB 170428A.
GCN 21051 table
GRB_name GRB170428A
GCN_number 21051
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 21051 SUBJECT: GRB 170428A: RATIR Afterglow Confirmation DATE: 17/04/29 18:40:36 GMT FROM: Eleonora Troja at GSFC Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara(UVI), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report: We observed the field of GRB 170428A (Beardmore, et al., GCN 21042) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2017/04 29.41 to 2017/04 29.48 UTC (24.69 to 26.25 hours after the BAT trigger), obtaining a total of 0.90 hours exposure in the r and i bands and 0.35 hours exposure in the Z, Y, J, and H bands. For a source at the candidate afterglow position (Bolmer, et al., GCN 21050), in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following detection and upper limits (3-sigma): r > 22.3 i 22.1 +/- 0.4 Z > 20.9 Y > 20.6 J > 20.1 H > 19.9 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Our observations show that the source reported by Bolmer, et al., (GCN 21050) significantly faded, and is therefore the afterglow of the short GRB170428A. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.
GCN 21052 table
GRB_name GRB170428A
GCN_number 21052
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 21052 SUBJECT: GRB 170428A: TAROT La Silla observatory optical observations DATE: 17/04/30 02:01:18 GMT FROM: Alain Klotz at IRAP-CNRS-OMP Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP), Boer, M., Laugier, R. (CNRS-ARTEMIS), Gendre B. (UVI - Etelman Obs.) report: We imaged the field of GRB 170428A detected by SWIFT (trigger 750298) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 25s after the GRB trigger (15s after the notice). The elevation of the field increased from 18 degrees above horizon and weather conditions were good. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT in the GROND position provided by Bolmer et al. (GCNC 21050) with a limiting magnitude of: t0+25s to t0+85s : Rlim = 17.5 The second image is 30.0s exposure in tracking mode: t0+98s to t0+128s : Rlim = 18.2 We co-added a series of exposures: t0+98s to t0+388s : Rlim = 19.2 Magnitudes were estimated with the nearby NOMAD1 stars and are not corrected for galactic dust extinction.
GCN 21053 table
GRB_name GRB170428A
GCN_number 21053
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 21053 SUBJECT: GRB 170428A: DCT Imaging DATE: 17/04/30 02:40:13 GMT FROM: S. Bradley Cenko at NASA/GSFC S. B. Cenko, E. Troja (NASA GSFC), E. Golden-Marx, E. Blanton (BU) report on behalf of a larger collaboration: We imaged the location of the optical afterglow (Bolmer et al., GCN 21050) of the short GRB170428A (Beardmore et al., GCN 21042) with the Large Monolithic Imager mounted on the 4.3m Discovery Channel Telescope in Happy Jack, AZ. Observations were obtained in the i-band filter beginning at 10:52 UT on 2017 April 29 (1.1 days after the GRB trigger). We detect emission at the reported afterglow position, and measure a magnitude of i = 22.2 +/- 0.2 mag (calibrated with respect to nearby point sources from SDSS), consistent with the measurement reported by Troja et al. (GCN 21051). We caution, however, that the candidate host galaxy (Bolmer et al., GCN 21050) is blended with this location due to poor seeing conditions - accurate afterglow photometry may require removing this host contamination.
GCN 21054 table
GRB_name GRB170428A
GCN_number 21054
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 21054 SUBJECT: Short GRB 170428A: MASTER-OAFA final reduction of the optical observations DATE: 17/05/01 11:13:25 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, D.Kuvshinov, A.V.Krylov, I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) , National University of San Juan, Argentina H. Levato, C. Saffe Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk, O. Ershova Irkutsk State University V.Yurkov, Yu.Sergienko Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in OAFA was pointed to the GRB170428A (Beardmore et al., GCN 21042) 17 sec after notice time and 31 sec after trigger time at 2017-04-28 09:14:14 UT (Podesta et al., GCN 21044). Our unfiletred limits are: Date time Exp Proc.type Lim. (s) 2017-04-28 09:14:14 10 Alert (SWIFT) 16.6 2017-04-28 09:15:04 20 Alert (SWIFT) 17.1 2017-04-28 09:16:07 30 Alert (SWIFT) 17.6 2017-04-28 09:17:19 40 Alert (SWIFT) 17.9 2017-04-28 09:18:42 60 Alert (SWIFT) 18.2 2017-04-28 09:20:24 80 Alert (SWIFT) 18.6 2017-04-28 09:17:19 180 SumAlert(SWIFT) 19.1 2017-04-28 09:22:28 110 Alert (SWIFT) 18.9 2017-04-28 09:24:59 140 Alert (SWIFT) 19.0 2017-04-28 09:28:01 170 Alert (SWIFT) 19.2 2017-04-28 09:22:28 420 SumAlert(SWIFT) 19.7 2017-04-28 09:31:33 180 Alert (SWIFT) 19.3 2017-04-28 09:35:16 180 Alert (SWIFT) 19.4 2017-04-28 09:38:59 180 Alert (SWIFT) 19.5 2017-04-28 09:31:33 540 SumAlert (SWIFT) 19.9 2017-04-28 09:42:42 180 Alert (SWIFT) 19.5 2017-04-28 09:48:50 180 Alert (SWIFT) 19.5 2017-04-28 09:55:02 180 Alert (SWIFT) 19.5 2017-04-28 09:42:42 540 SumAlert (SWIFT) 20.1 2017-04-28 09:58:46 180 Alert (SWIFT) 19.4 2017-04-28 10:02:26 180 Alert (SWIFT) 19.1 2017-04-28 10:06:07 180 Alert (SWIFT) 18.8 2017-04-28 09:58:46 540 SumAlert (SWIFT) 19.3 2017-04-28 10:09:49 180 Alert (SWIFT) 18.3 2017-04-28 09:31:33 1800 SumAlert (SWIFT) 20.3 2017-04-28 10:02:26 1440 SumAlert (SWIFT) 19.8 The message may be cited.
GCN 21055 table
GRB_name GRB170428A
GCN_number 21055
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 21055 SUBJECT: GRB 170428A: TNG optical observations DATE: 17/05/01 14:24:23 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo (INAF-OAB), V. D'Elia (INAF/OAR & ASI/ASDC), Daniele Malesani (DARK/NBI), S. Campana, G. Tagliaferri (INAF/OAB), G. Andreuzzi, D. Carosati (INAF-TNG) report on behalf of the CIBO collaboration: We observed the field of GRB 170428A (Beardmore et al., GCN 21042) with the 3.6m Telescopio Nazionale Galileo (TNG) equipped with DOLoRes. Observations were carried out in the i-sdss and z-sdss filters. Observations started on May 01 at 03:55:46 UT (~2.78 days after the burst) under a seeing of ~ 1.5". We clearly detect the candidate host galaxy reported by Xu et al. (GCN 21048). Some emission is also visible at the position of the optical afterglow (Bolmer et al., GCN 21050; Troja et al., GCN 21051; Cenko et al., GCN 21053), blended with the candidate host galaxy light. For the whole complex (afterglow and candidate host galaxy) we measure the following magnitudes: i(AB) = 22.1 +/- 0.1 at t-t0 = 2.79 d z(AB) = 21.9 +/- 0.1 at t-t0 = 2.81 d (calibrated against nearby SDSS stars). It is not possible, at this stage, to evaluate the afterglow contribution to the observed optical emission. Further observations are planned.
GCN 21058 table
GRB_name GRB170428A
GCN_number 21058
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 21058 SUBJECT: GRB 170428A: 15 GHz upper limits from AMI DATE: 17/05/02 17:27:34 GMT FROM: Kunal Mooley at Oxford U K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester) The AMI Large Array robotically triggered on the Swift alert for short GRB 170428A (Beardmore et al., GCN 21042) as part of the 4pisky program, and subsequent follow up observations were obtained up to 3 days post-burst. Our observations at 15 GHz on 2016 Apr 28.42 and Apr 30.34 (UT) do not reveal any radio source at the XRT location (Beardmore et al., GCN 21047), with 3sigma upper limits of 117 uJy and 96 uJy respectively. We thank the AMI staff for scheduling these observations. The AMI-GRB database is a log of all GRB follow up observations with the AMI, and is available at http://4pisky.org/ami-grb/.
GCN 21059 table
GRB_name GRB170428A
GCN_number 21059
Detection_method Other
redshift 0.4540
Circular_text TITLE: GCN CIRCULAR NUMBER: 21059 SUBJECT: GRB 170428A: GTC spectroscopic redshift of candidate host galaxy DATE: 17/05/02 17:43:47 GMT FROM: Zach Cano at U of Iceland ​​L. Izzo, Z. Cano (IAA-CSIC), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D. A. Kann, C. Thoene (IAA-CSIC), and S. Geier (IAC, GRANTECAN) report on behalf of a larger collaboration: We observed the field of short-duration GRB 170428A (Beardmore et al., GCN Circ. 21042) with OSIRIS mounted on the 10.4-m GTC telescope on La Palma (Spain) starting at 04:31:49 UT on 01 May 2017, at a mean time of +2.82 days from the GRB detection. The observations consisted of 4 x 900 s spectra using grism R1000R, which covers the wavelength range between 5100 and 10000 AA. In our r-band acquisition image, (30 second exposure time), we see the host candidate of Xu et al. (GCN Circ. 21048), which is also slightly visible in the r-band Pan-STARRS image. The slit was centred on the host galaxy candidate, and in the faint trace we detect emission lines corresponding to Halpha, [OIII] 5007, Hbeta, and [OII] 3726,3729, all at a common redshift of z=0.454. The angular separation between the candidate host and the GRB position determed by GROND (Bolmer et al., GCN Circ. 21050) is 1.2'' +- 0.3'', which at this redshift implies an offset of 6.9 kpc +- 1.7 kpc. GTC finder chart of the AG position and candidate host: http://www.iaa.es/~deugarte/GRBs/170428A/GTC.jpeg
GCN 21067 table
GRB_name GRB170428A
GCN_number 21067
Detection_method CALET
Circular_text TITLE: GCN CIRCULAR NUMBER: 21067 SUBJECT: GRB 170428A CALET Gamma-Ray Burst Monitor detection DATE: 17/05/04 08:47:22 GMT FROM: Takanori Sakamoto at AGU Y. Yamada, A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama, A. Tezuka, S. Matsukawa (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena) and the CALET collaboration: The short-duration GRB 170428A (Beardmore et al., GCN Circ. 21042; Tsvetkova et al., GCN Circ. 21045) was detected the CALET Gamma-ray Burst Monitor (CGBM) by the ground process pipeline at 09:13:42.36 on 28 April 2017 at 5.1 sigma which is below the trigger threshold of the on-board trigger. The burst signal was seen only by the SGM instrument. Because there was no on-board trigger, no event data were stored for this event. The continuous light curve data recorded in 0.125 s time resolution are not fine enough to investigate the temporal structure and the duration of this event. The light curve is available at http://cgbm.calet.jp/cgbm_trigger/flight/1177405621/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN 21942 table
GRB_name GRB170428A
GCN_number 21942
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 21942 SUBJECT: 3.6m Devasthal Optical Telescope observations of GRB 170428A DATE: 17/09/28 13:19:00 GMT FROM: Shashi Bhushan Pandey at ARIES, INDIA S. B. Pandey (ARIES Nainital), Brajesh Kumar, G. C. Anupama (IIA Bangaluru) and Kuntal Misra (ARIES Nainital) on behalf of a larger GRB collaboration Short-duration GRB 170428A (Swift trigger =750298, Beardmore et al. GCN 21042) was observed by the 3.6m Devasthal Optical Telescope (DOT) recently commissioned by ARIES Nainital. The observations were carried out as a part of early science run and characterizations. Observations were carried out just before twilight using the 4Kx4K CCD optical imager, the first light instrument. Several R-band exposures of 300-sec each were acquired in seeing conditions of around 1.1 arcsec starting around UT 22:45:57 i.e. 13.5 hours after the burst. In the stacked R-band frame of 3*300-sec, the candidate optical afterglow (Xu et al. GCN 21048; Bolmer et al. GCN 21050) was clearly seen embedded within the host galaxy. The photometry at the afterglow position measures a magnitude of 22.7+-0.2 mag (calibrated with respect to nearby USNO stars). However, in the present data-set, contamination with the probable host galaxy can not be ruled out in the estimated magnitude. This is the first GRB afterglow observations with the 3.6m DOT and the full team of staff members associated with the project are thankfully acknowledged to get this telescope commissioned. We expect to contribute towards observations of time critical events in near future assuming longitudinal advantage of Indian sub-continent using this facility. The message may be cited.