GRB090823A

This page lists all entries on GRB090823A in GRBweb

Summary IPN GCN 9835 GCN 9836 GCN 9838 GCN 9839 GCN 9840 GCN 9902

Summary table
Variable Value Source
T0 16:11:10.606 UTC GCN_circulars,Konus-Wind Det
ra 128.7125° IPN
decl 60.6667° IPN
pos_error 6.67e-02° IPN
GBM_located False
mjd 55066.67442831019 GCN_circulars,Konus-Wind Det
IPN table
GRB_name GRB090823A
ra 128.7125°
decl 60.6667°
pos_error 6.67e-02°
GCN 9835 table
GRB_name GRB090823A
GCN_number 9835
Detection_method IPN Triangulation
ra 228.7110°
decl 60.6600°
Circular_text TITLE: GCN CIRCULAR NUMBER: 9835 SUBJECT: GRB 090823 Long burst with IPN triangulation and BAT position DATE: 09/08/25 01:36:20 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (NASA/GSFC/CRESST) on behalf of the Swift-BAT team, S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team, M. Marisaldi, F. Fuschino, C. Labanti, M. Galli, G. Di Cocco on behalf of the AGILE team, K. Yamaoka, M. Ohno, Y. Fukazawa, T. Takahashi, M. Tashiro, Y. Terada, T. Murakami, K. Makishima, and Y. Hanabata on behalf of the Suzaku-WAM team, and K. Hurley for the IPN At 16:11:12 on 2009-08-23, GRB 090823 triggered the Suzaku WAM. The IPN was notified, and the burst was also observed by KONUS-Wind, Agile-MCAL, and (during a slew maneuver) Swift-BAT. A source was found in ground analysis of BAT event data, which is routinely collected during many pre-planned slews, and the source location was confirmed by IPN triangulation. The BAT position is RA, Dec 228.711, 60.660 which is equivalent to RA, Dec (J2000): 15:14:50.6, 60d 39' 36" with an uncertainty radius of 4 arcmin (estimated 90% containment, stat+sys). We have triangulated GRB 090823 to a Konus-WAM annulus centered at RA(2000)=141.472 (09h 25m 53s) Dec(2000)=+9.275 (+9d 16' 31"), whose radius is 52.640 4.346 deg (3 sigma). The BAT source is 0.384 deg (0.27 sigma) from the center line of the annulus. As observed in Suzaku-WAM and Agile-MCAL, the burst had two peaks at about T+1 and T+4 seconds, and had emission above 700 keV but not above 1.4 MeV. The BAT lightcurve shows that the emission began with a slow rise beginning about T-3 seconds, and decayed back to background rates by about T+20 seconds. The BAT event data, from which mask-weighted spectra and images are constructed, began at about T+10.5 seconds, missing 99% of the burst. A Swift Target of Opportunity has been requested and approved to follow up this burst with the Swift XRT and UVOT about 32 hours after the burst.
GCN 9836 table
GRB_name GRB090823A
GCN_number 9836
Detection_method Konus-Wind Det
t_trigger 16:11:10.606 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 9836 SUBJECT: Konus-Wind observations of GRB 090823 DATE: 09/08/25 10:11:26 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The long GRB 090823 (Cummings et al., GCN 9835) triggered Konus-Wind at T0=58270.606 s UT (16:11:10.606) This burst was also observed by the Suzaku WAM, Agile-MCAL, and (during a slew maneuver) Swift-BAT. The burst had a smooth structure with a duration of ~10 s. The Konus-Wind light curves of this GRB are available at http://www.ioffe.ru/LEA/GRBs/GRB090823_T58270/ As observed by Konus-Wind the burst had a fluence of 8.9(-0.3,+0.5)x10-6 erg/cm2, and a 256-ms peak flux, measured from T0+3.072, of 2.8(-0.25,+0.25)x10-6 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+14.848 s) is well fitted (in the 20 keV - 2 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with Alpha = -0.49(-0.15,+0.17), and Ep = 188(-15,+18)keV (chi2 = 56/61 dof). Fitting by the GRB (Band) model yields to the same Alpha and Ep values with the high energy photon index Beta of -7 (< -2.7) The spectrum at the maximum count rate, measured from T0 + 0.256s to T0 + 6.656s, is well fitted (in the 20 keV - 2 MeV range) by the GRB (Band) model with: Alpha = -0.45(-0.14,+0.16), Beta = -3.0(-2.2,+0.4), and Ep = 182(-18,+18)keV (chi2 = 63/60 dof). All the quoted values are preliminary. All the quoted errors are at the 90% confidence level.
GCN 9838 table
GRB_name GRB090823A
GCN_number 9838
Detection_method Swift-BAT Det
ra 128.7113°
decl 60.6600°
Circular_text TITLE: GCN CIRCULAR NUMBER: 9838 SUBJECT: GRB 090823 Correction to BAT position DATE: 09/08/25 12:56:41 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (NASA/GSFC/CRESST) Due to a typographical error, the RA of the source quoted for GRB 090823 in GCN #9835 was incorrect by a large amount. The correct BAT position was 128.711, 60.660 which is equivalent to RA, Dec (J2000): 8:34:50.7, 60d 39' 36" with an uncertainty radius of 4 arcmin (estimated 90% containment, stat+sys). I apologize for the error.
GCN 9839 table
GRB_name GRB090823A
GCN_number 9839
Detection_method Swift-BAT Det
ra 128.6710°
decl 60.6410°
Circular_text TITLE: GCN CIRCULAR NUMBER: 9839 SUBJECT: GRB 090823: Confirmation of Swift-BAT position by BAT Slew Survey DATE: 09/08/25 19:12:25 GMT FROM: Antonio Copete at Harvard U A. Copete, J. Grindlay (Harvard) S. Barthelmy, C. Markwardt, N. Gehrels (NASA/GSFC) We hereby report confirmation of the Swift-BAT position of GRB 090823 reported by Cummings et al. (GCN 9835, 9838), from an independent analysis of the BAT event-mode data done by the BAT Slew Survey (BATSS), in the slew that started at 16:10:02 UT and lasted 178 sec. The BATSS-calculated position is RA, Dec = 128.671, +60.641 deg, which is: RA (J2000) = 08h 34m 41s Dec(J2000) = +60d 38' 29" with an uncertainty of 4.51 arcmin (90% confidence, including systematics). The burst was detected with a significance of 6.2 sigma and 6.7 sigma from imaging in the 15-50 keV and 15-150 keV energy bands, respectively. Consistent with the report in GCN 9835, the lightcurve in the slew data only spans a 15-sec trailing edge of the prompt emission of the burst before it fades into the background.
GCN 9840 table
GRB_name GRB090823A
GCN_number 9840
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 9840 SUBJECT: GRB 090823: Swift XRT possible detection of the X-ray afterglow DATE: 09/08/25 19:20:00 GMT FROM: Dirk Grupe at PSU/Swift-XRT D. Grupe (PSU), E. Hoversten (PSU) and Jay Cummings (NASA/GSFC) report on behalf of the Swift team: We have analysed the XRT and UVOT data of the IPN burst GRB090823 (Cummings et al. GCN Circ. 9835), beginning on 2009-08-24 at 22:17, 30 hours after the Suzaku WAM trigger. The data contain 4.7 ks in XRT photon counting mode. We clearly detect a possible X-ray afterglow within the 4' BAT error circle given by Cummings and Copete et al. (GCN circs. 9838 and 9839, respectively) at RA-2000,Dec-2000=128.67676, +60.65169 which corresponds to RA-2000 = 08h 34m 42.42s Dec-2000 = +60d 39' 06.1" with an uncertainty of 5.5" During the 4.7 ks observation on 2009-08-24 the X-ray source had a count rate of (5.7+/-1.1)e-3 counts s-1 in the XRT which converts to an observed flux in the 0.3-10 keV band of (2.9+/-0.5)e-13 ergs s-1 cm-2 assuming a typical GRB afterglow spectrum. The Swift/UVOT began settled observations of the field of GRB 090823 108380 s after the BAT trigger (Cummings, et al., GCN Circ. 9835). No optical afterglow consistent with the XRT position is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the initial exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 109194 115699 1464 >21.8 v 110009 116640 1680 >20.1 u 108380 114954 1597 >20.7 The values quoted above 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). Swift is planning to re-observe the field of GRB 090823 on 2009-08-27 for 10 ks in order to see if the X-ray source has faded. This circular is an official product of the Swift team.
GCN 9902 table
GRB_name GRB090823A
GCN_number 9902
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 9902 SUBJECT: GRB 090823: Swift XRT confirmation of the X-ray afterglow DATE: 09/09/08 17:33:53 GMT FROM: Dirk Grupe at PSU/Swift-XRT D. Grupe (PSU) reports on behalf of the Swift XRT team: Swift has observed the field of IPN burst GRB090823 (Cummings et al. GCN Circ. 9835) twice after the initial 4.7 ks observation on 2009-08-24 (Grupe et al., GCN Circ. 9840) for 9.5 ks on 2009-08-27 and 7.5 ks on 2009-09-05. During the 2009-08-27 observation the X-ray source was clearly detected again at a level of (2.3+/-0.6)e-3 counts s-1 (about 1.1e-13 ergs s-1 cm-2), roughly half of the flux during the first observation. During the 2009-09-05 observation however, the X-ray source is definitely gone and we can only derive a 3-sigma upper limit at a level of 1.9e-3 counts s-1 (9.4e-14 ergs s-1 cm-2). We can confirm that the source listed in GCN circ. 9840 is the X-ray afterglow of GRB 090823.