GRB240703A

This page lists all entries on GRB240703A in GRBweb

Summary GCN 36809 GCN 36815 GCN 36820 GCN 36824

Summary table
Variable Value Source
T0 0:38:40 UTC GCN_circulars,Konus-Wind Det
ra 273.7662° GCN_circulars,Optical
decl -9.7008° GCN_circulars,Optical
GBM_located False
mjd 60494.02685185185 GCN_circulars,Konus-Wind Det
GCN 36809 table
GRB_name GRB240703A
GCN_number 36809
Detection_method Konus-Wind Det
t_trigger 0:38:40 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 36809 SUBJECT: Konus-Wind detection of GRB 240703A (a counterpart of EP240703a) DATE: 24/07/03 13:48:13 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: A long-duration GRB 240703A was detected by Konus-Wind (KW) in the waiting mode at ~00:38:32 UT. The burst source is located in the southern ecliptic hemisphere. Corrected for the propagation time, the burst was detected ~2 s before the start time of the fast X-ray transient EP240703a (T0=T0(EP)=00:38:40 UT; Wang et al., GCN 36807). The positional and temporal coincidence of this burst with the EP transient supports the conclusion that EP240315a is the GRB counterpart. A Bayesian block analysis of the KW waiting mode data in the 20-1250 keV band reveals a >12 sigma count rate increase in the interval from T0-2 s to T0+136 s. The burst light curve shows a multi-peaked structure with the brightest peak around ~T0+13 s. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB240703A/ The time-integrated spectrum of the burst, measured from T0-2 s to T0+136 s, is best described by a power law with exponential cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.09(-0.30,+0.47) and Ep = 180(-44,+62) keV. The spectrum near the peak count rate, measured from T0-2 s to T0+33 s, can be described by a CPL model with alpha = -0.75(-0.33,+0.41) and Ep = 276(-58,+81) keV. The total burst fluence is 1.36(-0.18,+0.18)x10^-5 erg/cm^2, and the 2.944 s peak energy flux, measured from T0+12.5 s, is 2.8(-0.4,+0.4)x10^-7 erg/cm^2. (both in the 20 keV - 10 MeV energy range). All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.
GCN 36815 table
GRB_name GRB240703A
GCN_number 36815
Detection_method Optical
ra 273.7662°
decl -9.7008°
Circular_text TITLE: GCN CIRCULAR NUMBER: 36815 SUBJECT: EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate DATE: 24/07/03 18:28:56 GMT FROM: Dong Xu at NAOC/CAS J. An, S.Q. Jiang (NAOC), S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), X. Liu, S.Y. Fu, Z.P. Zhu, D. Xu, Z. Fan, W.X. Li, N.C. Sun, Y.N. Wang (NAOC) report on behalf of a large collaboration: We observed the field of the X-ray transient, EP240703a, detected by EP/WXT (Wang et al., GCN 36807), and also by Konus-Wind (Frederiks et al., GCN 36809), thus confirming that it is likely GRB 240703A, using the Thai Response Telescope (TRT) SBO node and the JinShan 100C & 50A telescopes. Image subtraction of the stacked 5 x 360 s R-band TRT image against the PanSTARRS archival r-band image reveals multiple optical afterglow candidates, among which an uncatalogued optical transient (OT) is localized at coordinates R.A. (J2000) = 18:15:03.89 Dec. (J2000) = -09:42:02.96 with an uncertainty of ~ 0.5 arcsec. The OT has r ~ 20.4 +/- 0.1 mag at a median time of ~ 13.9 hr post-trigger, calibrated with nearby PanSTARRS stars and not corrected for Galactic extinction of A_r ~ 3 mag. We then obtained 10 x 300 s frames in the Sloan r-band and 10 x 300 s in the Sloan z-band at the JinShan 100C telescope. The OT is not detected in the stacked r-band image down to r ~ 22.2 mag at a median time of 16.07 hr post-trigger, also not detected in z-band down to z ~ 20.6 mag at a median time of 16.91 hr post-trigger, both calibrated with the nearby PanSTARRS field. The presence and the decay of the OT make it an optical afterglow candidate of EP240703a/GRB 240703A.
GCN 36820 table
GRB_name GRB240703A
GCN_number 36820
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 36820 SUBJECT: EP240703a/GRB 240703A: TRT optical candidate likely not real DATE: 24/07/04 10:42:33 GMT FROM: Dong Xu at NAOC/CAS J. An (NAOC), S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), S.Q. Jiang, X. Liu, S.Y. Fu, Z.P. Zhu, D. Xu, Z. Fan, W.X. Li, N.C. Sun, Y.N. Wang (NAOC) report on behalf of a large collaboration: Regarding our previously reported afterglow candidate of EP240703a/GRB 240703A (An et al., GCN 36815), we have checked the five 360 s R-band TRT images one by one. First, the candidate is only present in one of the five images, and not in the other four images. Second, it looks sharper than its neighboring sources, although it does cover multiple pixels in the image. We thus re-did cosmic ray removal with a revised script, and this time the candidate basically disappeared while its neighboring sources were almost unaffected by the same cosmic ray removal process. We thus conclude that the candidate is very likely not real.
GCN 36824 table
GRB_name GRB240703A
GCN_number 36824
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 36824 SUBJECT: EP240703a: BTA observations DATE: 24/07/04 22:54:06 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Volnova (IKI), A. Moskvitin (SAO RAS), A. Pozanenko (IKI), D. Oparin (SAO RAS), N. Pankov (IKI, HSE), S. Belkin (IKI, HSE) on behalf of GRB IKI FuN report: We observed the TRT candidate afterglow position (An et al., GCN 36815) of the X-ray transient EP240703a (Wang et al., GCN 36807) and probable gamma-ray burst GRB 240703A (Frederiks et al., GCN 36809) with BTA SAO RAS telescope equipped with SCORPIO-1 camera in Ic filter starting on 2024-07-03 (UT) 20:50:07, i.e. 0.856 days after burst. We did not detect the TRT candidate afterglow (An et al., GCN 36815) which might be a spurious event (An et al., GCN 36820). At the stacked images of 9x180 s we obtained an upper limit of Ic= 24.6m (3 sigma). We cannot confirm that the TRT afterglow candidate (An et al., GCN 36815) is real. Our result is consistent with reported results (Aryan et al., GCN 36819, Bochenek and Perley GCN 36821; Fernandez-Garcia et al., GCN 36822). We are grateful to the Directorate of the Special Astrophysical Observatory for allocation of the TOO observation.