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This page lists all entries on GRB210724A in GRBweb

Summary IPN Swift GCN 30497 GCN 30498 GCN 30511 GCN 30513 GCN 30515 GCN 30518 GCN 30529 GCN 30547 GCN 30551

Summary table
Variable	Value	Source
T0	20:14:09 UTC	GCN_circulars,Swift Det
ra	227.4146°	Swift
decl	-6.2907°	Swift
pos_error	3.88e-04°	Swift
T90	50.57 s	Swift
T90_start	20:14:09 UTC	Swift
fluence	1.80e-06 erg/cm²	Swift
T100	50.57 s
GBM_located	False
mjd	59419.84315972222	GCN_circulars,Swift Det

IPN table
GRB_name	GRB210724A
ra	227.4083°
decl	-6.2667°
pos_error	5.00e-02°

Swift table
GRB_name	GRB210724A
t_trigger	20:14:09 UTC
ra	227.4146°
decl	-6.2907°
pos_error	3.88e-04°
T90	50.57 s
fluence	1.80e-06 erg/cm²

GCN 30497 table
GRB_name	GRB210724A
GCN_number	30497
Detection_method	Swift Det
t_trigger	20:14:09 UTC
ra	227.4070°
Circular_text	TITLE: GCN CIRCULAR NUMBER: 30497 SUBJECT: GRB 210724A: Swift detection of a burst DATE: 21/07/24 20:37:28 GMT FROM: David Palmer at LANL P. D'Avanzo (INAF-OAB), M. G. Bernardini (INAF-OAB), J. A. Kennea (PSU), N. J. Klingler (GSFC/UMBC/CRESSTII), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), D. M. Palmer (LANL) and T. Sbarrato (INAF-OAB) report on behalf of the Neil Gehrels Swift Observatory Team: At 20:14:09 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210724A (trigger=1061482). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 227.407d, -6.274d which is RA(J2000) = 15h 09m 38s Dec(J2000) = -06d 16' 27" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Due to a telemetry outage the BAT lightcurve is not immediately available. However, the trigger information indicates a duration of at least 4 seconds. The XRT began observing the field at 20:17:09.0 UT, 179.8 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 227.4118, -6.2911 which is equivalent to: RA(J2000) = 15h 09m 38.83s Dec(J2000) = -06d 17' 27.8" with an uncertainty of 1.9 arcseconds (radius, 90% containment). 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 consistent with the Galactic value of 8.23 x 10^20 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 124 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 0.097. Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)

GCN 30498 table
GRB_name	GRB210724A
GCN_number	30498
Detection_method	Swift Det
t_trigger	20:27:37 UTC
Circular_text	TITLE: GCN CIRCULAR NUMBER: 30498 SUBJECT: GRB210724A: MeerLICHT upper limits DATE: 21/07/24 22:56:14 GMT FROM: Simon de Wet at University of Cape Town S. de Wet (UCT), P.J. Groot (Radboud/UCT/SAAO), A.J. Levan (Radboud), P.M. Vreeswijk (Radboud), report on behalf of the MeerLICHT consortium: Following the detection of GRB210724A by Swift and its X-ray counterpart (D'Avanzo et al., GCN30497), the 0.6m MeerLICHT telescope, located at Sutherland, South Africa obtained a repeating series of 60s images in the q,u,q,g,q,r,q,i,q,z bands. Observations began at 2021-07-24, 20:25:18.02 UT, 11 minutes after the Swift detection, and 2 minutes after the distribution of the BAT alert, and continued untill 21:27:36 UT. We detect no optical afterglow at the XRT position (DAvanzo et al. GCN30497) in our first u,g,q,r,i,z exposures to 5-sigma limiting magnitudes of: u > 18.59 at 20:27:37 UT g > 19.40 at 20:31:01 UT q > 19.77 at 20:25:49 UT r > 19.38 at 20:34:31 UT i > 19.26 at 20:37:45 UT z > 18.14 at 20:59:12 UT Full moon conditions limited the depth of our exposures. We do note that an r=21.5 object is visible within the XRT localisation in PanSTARRS imaging of the field, and is a plausible host galaxy. MeerLICHT is built and run by a consortium consisting of Radboud University, University of Cape Town, the South African Astronomical Observatory, the University of Oxford, the University of Manchester and the University of Amsterdam. Disclaimer - University of Cape Town This email is subject to UCT policies and email disclaimer published on our website at http://www.uct.ac.za/main/email-disclaimer or obtainable from +27 21 650 9111. If this email is not related to the business of UCT, it is sent by the sender in an individual capacity. Please report security incidents or abuse via https://csirt.uct.ac.za/page/report-an-incident.php.

GCN 30511 table
GRB_name	GRB210724A
GCN_number	30511
Detection_method	Optical
Circular_text	TITLE: GCN CIRCULAR NUMBER: 30511 SUBJECT: GRB 210724A: Afterglow candidate from OSIRIS/GTC DATE: 21/07/25 16:50:29 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (HETH/IAA-CSIC,DARK/NBI), C. C. Thoene, D. A. Kann, M. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC), J. P. U. Fynbo (DAWN/NBI), L. Izzo (DARK/NBI), N. R. Tanvir (U. Leicester), N. Castro-Rodriguez, and A. Marante (GRANTECAN, IAC) report: We observed the field of GRB 210724A (D'Avanzo et al. GCN 30497) with OSIRIS mounted on the 10.4 m GTC telescope at the Roque de los Muchachos observatory (La Palma, Spain). Observations started at 22:07 UT (1.88 hr after the burst). Observations were affected by strong calima and the full Moon, which resulted in bad transparency and very high background. In a series of short images in r', i' and z' bands we detect a new source, not present in the PanSTARRS catalogue images. The object is located at (J2000 +/- 0.5"): RA: 15:09:39.44 Dec.: -06:17:26.0 This object had a magnitude of r' = 22.00 +/- 0.15 mag as compared to PanSTARRS field stars. We note that this source is within the early XRT alert error circles but outside the refined one (D'Avanzo et al. GCN 30497). There is no new source detected within this refined error circle. Due to the fact that this source is significantly brighter than the PanSTARRS limit, we propose it as the optical counterpart of GRB 210724A.

GCN 30513 table
GRB_name	GRB210724A
GCN_number	30513
Detection_method	Swift-BAT Det
ra	227.4250°
decl	-6.2790°
Circular_text	TITLE: GCN CIRCULAR NUMBER: 30513 SUBJECT: GRB 210724A: Swift-BAT refined analysis DATE: 21/07/25 19:43:26 GMT FROM: Amy Lien at GSFC S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC), P. D'Avanzo (INAF-OAB), H. A. Krimm (NSF), 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-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 210724A (trigger #1061482) (D'Avanzo et al., GCN Circ. 30497). The BAT ground-calculated position is RA, Dec = 227.425, -6.279 deg which is RA(J2000) = 15h 09m 41.9s Dec(J2000) = -06d 16' 42.9" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 34%. The mask-weighted light curve shows a multi-peaked structure that starts at ~T-40 s and ends at ~T+25 s. The main peak occurs at ~T0. T90 (15-350 keV) is 50.57 +- 9.54 sec (estimated error including systematics). The time-averaged spectrum from T-38.55 to T+25.50 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.30 +- 0.28. The fluence in the 15-150 keV band is 1.8 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.51 sec in the 15-150 keV band is 2.5 +- 0.8 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/1061482/BA/

GCN 30515 table
GRB_name	GRB210724A
GCN_number	30515
Detection_method	Swift-XRT Other
ra	227.4113°
decl	-6.2901°
Circular_text	TITLE: GCN CIRCULAR NUMBER: 30515 SUBJECT: GRB 210724A: Swift-XRT refined Analysis DATE: 21/07/25 21:43:29 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and P. D'Avanzo report on behalf of the Swift-XRT team: We have analysed 2.5 ks of XRT data for GRB 210724A (D'Avanzo et al. GCN Circ. 30497), from 123 s to 84.6 ks after the BAT trigger. The data comprise 263 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. Using 331 s of PC mode data and 1 UVOT image, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 227.41131, -6.29009 which is equivalent to: RA (J2000): 15h 09m 38.72s Dec(J2000): -06d 17' 24.3" with an uncertainty of 2.0 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=1.17 (+0.10, -0.09). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.48 (+/-0.08). The best-fitting absorption column is 2.08 (+0.23, -0.22) x 10^21 cm^-2, in excess of the Galactic value of 8.2 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.8 x 10^-11 (4.9 x 10^-11) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Total column: 2.08 (+0.23, -0.22) x 10^21 cm^-2 Galactic foreground: 8.2 x 10^20 cm^-2 Excess significance: 9.5 sigma Photon index: 2.48 (+/-0.08) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01061482. This circular is an official product of the Swift-XRT team.

GCN 30518 table
GRB_name	GRB210724A
GCN_number	30518
Detection_method	Optical
Circular_text	TITLE: GCN CIRCULAR NUMBER: 30518 SUBJECT: GRB 210724A: Zeiss-1000 of Koshka observatory, optical upper limit DATE: 21/07/26 12:14:12 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Novichonok (Petrozavodsk State University, KIAM), A. Pozanenko (IKI), A. Zhornichenko (KIAM), N. Pankov (HSE) report on behalf of IKI GRB FuN: We observed the field of GRB 210724A (D'Avanzo et al. GCN 30497) with Zeiss-1000 telescope of Koshka observatory starting on July 24 (UT) 20:39:32. We do not detect any object XRT error circle (D'Avanzo et al. GCN 30497). We also not detect the object at the position of the afterglow candidate (Ugarte Postigo et al., GCN 30511). Preliminary photometry of the field is following Date UT start t-T0 Filter Exp. OT Err. UL(3sigma) (mid, days) (s) 2021-07-24 20:39:32 0.024919 R 21*60 n/d n/d 18.6 The photometry is based on the nearby USNO-B1.0 stars USNO-B1.0_id R2 USNO-B1.0_id R2 0837-0267865 15.24 0836-0268753 16.95 0837-0267827 15.54

GCN 30529 table
GRB_name	GRB210724A
GCN_number	30529
Detection_method	Swift-UVOT Other
Circular_text	TITLE: GCN CIRCULAR NUMBER: 30529 SUBJECT: GRB 210724A: Swift/UVOT Upper Limits DATE: 21/07/27 06:17:13 GMT FROM: Sam LaPorte at PSU GRB 210724A: Swift/UVOT Upper Limits S. J. LaPorte (PSU) and P. D'Avanzo (INAF-OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 210724A 125 s after the BAT trigger (D'Avanzo et al., GCN Circ. 30497). No optical afterglow consistent with the XRT position (D'Avanzo et al. GCN Circ. 30497) 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 125 275 147 >20.8 u_FC 283 513 226 >20.1 white 125 275 147 >20.8 u 283 513 227 >20.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.097 in the direction of the burst (Schlegel et al. 1998).

GCN 30547 table
GRB_name	GRB210724A
GCN_number	30547
Detection_method	Swift-XRT Other
ra	227.4146°
decl	-6.2907°
Circular_text	TITLE: GCN CIRCULAR NUMBER: 30547 SUBJECT: GRB 210724A: Corrected Swift-XRT enhanced position DATE: 21/07/29 15:25:48 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) and P. D'Avanzo (INAF-OAB) report on behalf of the Swift-XRT team. The XRT position of GRB 210724A reported in GCN Circ. 30515 was 11" from the position of the optical candidate found by de Ugarte Postigo et al. (GCN Circ. 30511). Unusually, this position underwent significant variation during the normal revisions after each data downlink. Investigation has revealed a rare local minimum issue during the first XRT image, which has now been fixed. The best XRT position is RA, Dec = 227.41461, -6.29070 which is equivalent to: RA (J2000): 15h 09m 39.51s Dec(J2000): -06d 17' 26.5" with an uncertainty of 3.0 arcsec (radius, 90% confidence). This position is 1.1" from the optical position of de Ugarte Postigo et al. We apologise for the confusion caused by this rare glitch, which coincided with the author's vacation (Murphy et al). As ever, the most recent version of the position can be found online at: https://www.swift.ac.uk/xrt_positions/01061482/ This circular is an official product of the Swift-XRT team.

GCN 30551 table
GRB_name	GRB210724A
GCN_number	30551
Detection_method	Other
Circular_text	TITLE: GCN CIRCULAR NUMBER: 30551 SUBJECT: GRB 210724A: Early CAHA 2.2m limit DATE: 21/07/30 12:37:10 GMT FROM: Alexander Kann at IAA-CSIC D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. Thoene, M. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC), A. Gardini, and I. Hermelo (both CAHA) report: We observed the in-flight XRT afterglow position (revised in Evans et al., GCN #30547) of GRB 210724A (D'Avanzo et al., GCN #30497) with CAFOS mounted at the 2.2m Calar Alto telescope (Almeria, Spain), under very adverse conditions (high airmass, strong Calima, clouds, bad seeing, strong moonlight - the works). We obtained 10 x 180 s images in r', starting on July 24, 21:07:08 UT (0.8831 h after the burst). At the position of the GTC afterglow candidate (de Ugarte Postigo et al., GCN #30511), we detect no source down to r' > 22.0 mag (AB magnitude) against PanSTARRS comparison stars, at midtime 0.0482 d (1.1569 h) after the burst. This is of similar depth as the detection by de Ugarte Postigo et al., GCN #30511, perhaps indicating a slowly rising afterglow, or at least one that is not steeply decaying.