GRB110825A

This page lists all entries on GRB110825A in GRBweb

Summary Fermi GBM IPN GCN 12307 GCN 12308 GCN 12309 GCN 12311 GCN 12313 GCN 12314 GCN 12315 GCN 12318 GCN 12334 GCN 12403

Summary table
Variable Value Source
GRB_name_Fermi GRB110825102
T0 2:26:50.938 UTC Fermi_GBM
ra 44.8958° IPN
decl 15.4000° IPN
pos_error 2.00e+00° IPN
T90 62.465 s Fermi_GBM
T90_error 0.231 s Fermi_GBM
T90_start 2:27:02.586 UTC Fermi_GBM
fluence 4.61e-05 erg/cm² Fermi_GBM
fluence_error 1.11e-07 erg/cm² Fermi_GBM
T100 74.113 s
GBM_located False
mjd 55798.10197844907 Fermi_GBM
Fermi GBM table
GRB_name_Fermi GRB110825102
trigger_name bn110825102
ra 44.8958°
decl 15.4069°
pos_error 2.48e+00°
datum 2011-08-25
t_trigger 2:26:50.938 UTC
T90 62.465 s
T90_error 0.231 s
T90_start 2:27:02.586 UTC
fluence 4.61e-05 erg/cm²
fluence_error 1.11e-07 erg/cm²
flux_1024 5.37e+01 erg/cm²/s
flux_1024_error 4.36e-01 erg/cm²/s
flux_1024_time 1.55e+01 erg/cm²/s
flux_64 7.88e+01 erg/cm²/s
flux_64_error 1.88e+00 erg/cm²/s
IPN table
GRB_name GRB110825A
ra 44.8958°
decl 15.4000°
pos_error 2.00e+00°
GCN 12307 table
GRB_name GRB110825A
GCN_number 12307
Detection_method IPN Triangulation
Circular_text TITLE: GCN CIRCULAR NUMBER: 12307 SUBJECT: IPN triangulation of GRB110825A (very intense, long-duration) DATE: 11/08/26 17:53:40 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, on behalf of the MESSENGER GRB team, I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, K. Yamaoka, M. Ohno, Y. Hanabata, Y. Fukazawa, T. Takahashi, M. Tashiro, Y. Terada, T. Murakami, and K. Makishima on behalf of the Suzaku WAM team, S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, J. Goldsten, on behalf of the MESSENGER NS GRB team, G. Di Cocco, F. Fuschino, M. Galli, C. Labanti, M. Marisaldi, on behalf of the AGILE MCAL team, and V. Connaughton, M. S. Briggs, and C. Meegan, on behalf of the Fermi GBM team, report GRB110825A (=Fermi GBM trigger 335932012) was observed by AGILE MCAL (outside the coded field of view of SuperAGILE), Fermi GBM, MESSENGER GRNS, Odyssey HEND, Suzaku WAM, and Swift BAT (outside the coded field of view). We have triangulated it to a preliminary, 3 sigma error box whose area is 252 square arcminutes and whose coordinates are: RA DEC CENTER: 44.896 o= 2 h 59 m 35.1 s 15.407 o= 15 o 24' 25" CORNERS: 45.160 o= 3 h 00 m 38.3 s 14.528 o= 14 o 31' 39" 44.959 o= 2 h 59 m 50.1 s 15.336 o= 15 o 20' 11" 44.834 o= 2 h 59 m 20.1 s 15.478 o= 15 o 28' 42" 44.595 o= 2 h 58 m 22.7 s 16.428 o= 16 o 25' 40" This preliminary error box has been posted at ssl.berkeley.edu/ipn3/110825A; it can be improved. A Swift ToO has been carried out, and the results of that observation, as well as the details of the burst, will be reported in forthcoming GCN Circulars.
GCN 12308 table
GRB_name GRB110825A
GCN_number 12308
Detection_method Swift Other
ra 44.7985°
decl 15.4273°
Circular_text TITLE: GCN CIRCULAR NUMBER: 12308 SUBJECT: GRB110825A: Swift target of opportunity observation DATE: 11/08/26 21:29:20 GMT FROM: Binbin Zhang at PSU B.-B. Zhang (PSU) and D. Grupe (PSU) reports on behalf of the Swift-XRT team: Swift began a target of opportunity observation of the IPN-detected burst: GRB110825A (Hurley et al. et al. GCN Circ. 12307) on August 26, 2011 at 01:05 UT, approximately 22.7 hours after the burst was detected by IPN. Swift data for these observations utilize Target ID 20183. We have analysed 2.9 ks of XRT data for this burst, from 81.3 ks to 94.0 ks after the IPN trigger. The data are entirely in Photon Counting (PC) mode. An X-ray source is detected within the XRT field-of-view. The refined XRT position is RA, Dec = 44.79846, +15.42733 which is equivalent to: RA (J2000): 02 59 11.63 Dec(J2000): +15 25 38.4 with an uncertainty of 3.9 arcsec (radius, 90% confidence). This position is 346 arcsec from the IPN position and about 180 arcsec from the edge of IPN error box (see http://www.personal.psu.edu/buz12/IPN_ERRORBOX_VS_XRT_GRB110825A.png). We cannot determine at the present time whether the source is fading. A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.8 (+0.8, -0.4). The best-fitting absorption column is consistent with the Galactic value of 9.9 x 10^20 cm^-2 (Kalberla et al. 2005). The count rate for the X-ray source is about 0.01 count/sec, which is relatively bright when comparing to other GRB's X-ray afterglow at t-T0=10^5 seconds. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.9 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 0 (+1.7, -0) x 10^21 cm^-2 Galactic foreground: 9.9 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.8 (+0.8, -0.4) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020183. No source was found from UVOT data within the XRT error circle. Preliminary 3-sigma up-limits are : Filter EXPOSURE Mag --------------------------------------------------- v & 579 & >19.19 u & 1365 & >20.79 white & 895.63 & >21.40 --------------------------------------------------- We notice that there is no known source at the X-ray source position in Simbad or the NED. We also notice that the RASS data for this position were not deep enough to detect a source of this flux (0.01 count/sec). We have scheduled further Swift TOO for this target. This circular is an official product of the Swift-XRT team. Burst Advocate for this burst is B.-B. Zhang (bbzhang 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/too.html.)
GCN 12309 table
GRB_name GRB110825A
GCN_number 12309
Detection_method IPN Triangulation
ra 44.7999°
decl 15.4282°
Circular_text TITLE: GCN CIRCULAR NUMBER: 12309 SUBJECT: GRB 110825A: field inspection and possible host galaxy DATE: 11/08/27 00:09:52 GMT FROM: Dong Xu at Weizmann Inst D. Xu reports on behalf of a larger collaboration: We inspected the archival datasets of the XRT field (Zhang & Grupe, GCN 12308) of GRB 110825A (Hurley et al., GCN 12307). We found an extended (in the SE-NW direction) object centered at RA (J2000): 02:59:11.966 Dec(J2000): +15:25:41.34 which is 5.7 arcsec to the center of the XRT error circle with a radius of 3.9 arcsec (90% confidence; GCN 12308). Therefore, if the XRT source is really the counterpart of IPN-triangulated GRB110825A or even of a new burst (as the XRT position is outside the IPN error box), the extended object could be the host galaxy of this event. Inspection of the archives reveals the extended object: (1) being U1050_00797295 (USNO at ESO) with r=18.4 mag and b=19.2 mag; (2) being 02591193+1525410 (2MASS at CADC) with J=16.493+/-0.140 mag, H=15.810+/-0.134 mag, and K=15.210+/-0.149 mag; and (3) being 1054-0031516 (USNO B1 at CDS) with R1=18.91 mag and B1=19.84 mag. In addition, preliminary UVOT photometry (standard 5arcsec aperture photometry) centered on the above location reveals v(AB)>19.28 u(AB)>21.90 wh(AB)=21.55 +/- 0.21 More accurate UVOT photometry is required as the OT is extended and relatively faint for the UVOT telescope. Considering the above possible host galaxy is brighter than usual GRB hosts, this source might be a low-redshift one.
GCN 12311 table
GRB_name GRB110825A
GCN_number 12311
Detection_method Optical
ra 44.7986°
decl 15.4277°
Circular_text TITLE: GCN CIRCULAR NUMBER: 12311 SUBJECT: GRB 110825A: optical afterglow candidate DATE: 11/08/27 10:17:19 GMT FROM: Dong Xu at Weizmann Inst D. Xu (WIS), S. Schulze, P. Jakobsson (U. Iceland), and F. Faedi (QUB) report: We observed the field (Zhang & Grupe, GCN 12308) of GRB 110825A (Hurley et al., GCN 12307) with the Nordic Optical Telescope (NOT) equipped with ALFOSC. We obtained 4x300s R-band imaging, starting at 05:07:08 UT on 27th August 2011. Only the first frame is useful due to cloudy weather and relatively bright background towards the morning twilight. An optical object was weakly detected within the XRT error circle (GCN 12308), localised at RA (J2000): 02:59:11.674 Dec(J2000): +15:25:39.84 Error circle radius: ~0.2 arcsec which is about 3.9 arcsec to the extended object reported in our previous GCN 12309. The source has R~23.6 mag calibrated to nearby stars in the USNO B1 catalog. No further observation with the NOT is planned.
GCN 12313 table
GRB_name GRB110825A
GCN_number 12313
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 12313 SUBJECT: GRB110825A: ROTSE early time optical limit DATE: 11/08/27 15:36:56 GMT FROM: Weikang Zheng at U.of Michigan W. Zheng & C. Akerlof (U Mich), report on behalf of the ROTSE collaboration: ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe, Turkey, responded to GRB 110801A (Hurley et al. GCN 12307; GBM trigger 335932012) near dawn condition. The first image started at Aug. 25 02:30:44 UT, ~ 242 seconds after the GBM trigger. Observation was performed in 4x4 tiling mode around the center of the GBM trigger with exposure time of 20 seconds for each image. Useful image last up to ~1000 seconds after trigger due to bright dawn background after that. The optical afterglow location (Xu et al. GCN 110825) within XRT error (Zhang & Grupe GCN 12308) is covered in 8 ROTSE images. We do not detecte the optical afterglow. We summarize the upper limit result below (clear band data, calibrated to USNO A-1.0): ------------------------------------ t-t0(s) exp(s) 3-sigma upper limit 301.3 20.0 15.6 418.8 20.0 15.3 448.2 20.0 15.3 477.5 20.0 15.3 771.1 20.0 14.6 888.2 20.0 14.5 917.4 20.0 14.5 946.7 20.0 14.4
GCN 12314 table
GRB_name GRB110825A
GCN_number 12314
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 12314 SUBJECT: GRB 110825A: GMG optical observation DATE: 11/08/28 12:03:44 GMT FROM: Xiao-hong Zhao at Nanjing University X. H. Zhao (YNAO), D. Xu (WIS), J. M. Bai (YNAO), report on behalf of a larger collaboration: We observed the XRT field (Zhang & Grupe, GCN 12308) of GRB 110825A (Hurley et al., GCN 12307) with the 2.4m Gao-Mei-Gu (GMG) telescope equipped with YFOSC in Yunan, China. Observations started at 19:02:36 UT on 27th August 2011 and 3x1200s R-band images were obtained. The possible optical afterglow candidate, derived from a weak detection from a single frame (Xu et al., GCN 12311) is not detected in our stacked R-band image, which gives rise to a 3sigma upper limit of R~23.9 mag for the XRT error circle, calibrated with the same USNO reference star in GCN 12311. No further observation with the GMG telescope is planned.
GCN 12315 table
GRB_name GRB110825A
GCN_number 12315
Detection_method Suzaku WAM Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 12315 SUBJECT: GRB 110825A: Suzaku WAM observation of the prompt emission DATE: 11/08/29 20:41:15 GMT FROM: Kazutaka Yamaoka at Aoyama Gakuin U K. Yamaoka (Aoyama Gakuin U.), N. Ohmori, M. Akiyama, M. Yamauchi (Univ. of Miyazaki), M. Ohno, Y. Hanabata, T. Uehara, T. Takahashi, M. Mizuno, Y. Fukazawa (Hiroshima U.), S. Sugita (Nagoya U.), T. Yasuda, Y. Terada, W. Iwakiri, K. Takahara, M. Asahina, S. Kobayashi, M. Tashiro (Saitama U.), M. Kokubun, T. Takahashi (ISAS/JAXA), Y. E. Nakagawa (Waseda U.), Y. Urata, P. Tsai, C-J. Chuang (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo), on behalf of the Suzaku WAM team, report: The bright, long GRB110825A (localized by IPN; Hurley et al. GCN 12307) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 02:27:03.410 UT (=T0). The observed light curve shows multiple peaks starting at T0-3 s, ending at T0+8 s, with a duration (T90) of about 6.9 seconds. The fluence in the 100 - 1000 keV range was 1.88 +/- 0.14 x 10^-5 erg/cm^2. The 1-s peak flux measured from T0+3 s was 17.0 +/- 0.8 photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-3 s to T0+8 s is well fitted by a power-law with exponential cutoff model: dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with alpha : 1.28 (-0.40, +0.34), and Epeak : 248 (-47, +41) keV (chi^2/d.o.f. = 19.4/21). All the quoted errors are at statistical 90% confidence level, in which systematic uncertainties are not included. The light curves for this burst are available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
GCN 12318 table
GRB_name GRB110825A
GCN_number 12318
Detection_method Fermi GBM Det
t_trigger 2:26:50.940 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 12318 SUBJECT: GRB110825A: Fermi GBM observation DATE: 11/08/30 21:11:14 GMT FROM: Sinead McGlynn at Excellence Cluster/TUM S. McGlynn (MPE/Excellence Cluster) reports on behalf of the Fermi GBM Team: "At 02:26:50.94 UT on 25 August 2011, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 110825A (trigger 335932012 / 110825102), which was also localised by the IPN (Hurley et al. 2011, GCN 12307). The angle from the Fermi LAT boresight at trigger time was 65 degrees. Approximately 100 s from trigger time, the Fermi spacecraft executed an automatic maneuver in response to a command from GBM, in order to place the burst closer to the LAT boresight. The GBM light curve shows a soft precursor (~2s) followed by 2 bright peaks from T0+10s to T0+25s, with a possible soft tail at T0+75 to T0+85s. The duration (t90) is 62.5 +/- 0.2 s (50-300 keV). The time-averaged spectrum from T0-0.64 s to T0+82.3 s is best fit by a Band function with Epeak = 233.6 (+21.9/-19.9) keV, alpha = -1.23 (+/-0.03), and beta = -2.04 (+0.06/-0.08) (C-Stat 719.72 for 490 d.o.f.). The event fluence (10-1000 keV) in this time interval is (5.45 +/- 0.70)E-5 erg/cm^2. The 1 s peak photon flux measured starting from T0+15.5 s in the 10-1000 keV band is 53.7 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN 12334 table
GRB_name GRB110825A
GCN_number 12334
Detection_method Swift-XRT Other
ra 2.0000°
decl 15.0000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 12334 SUBJECT: GRB 110825A: Further Swift/XRT Observations DATE: 11/09/12 20:59:08 GMT FROM: Binbin Zhang at PSU B.-B. Zhang (PSU), D. Grupe (PSU), D. N. Burrows (PSU), J. Gelbord (PSU) and S. D. Barthelmy (GSFC) report on behalf of the Swift-XRT team: We report further observations of the possible X-ray counterpart (Zhang & Grupe, GCN 12308) of the IPN-detected burst GRB 110825A (Hurley etal., GCN 12307). The Swift/XRT found a relatively bright X-ray source located at RA (J2000): 02 59 11.63 Dec(J2000): +15 25 38.4. We performed follow-up XRT observations of this field at T0+1 day, T0+5 days,T0+12 days and T0+16 days (where T0 = 2011 Aug 25 at 02:26:48.0 UT ), in order to determine whether or not the X-ray source had faded. The observed count rates in the 0.3-10 keV band are as follows : T-T0 Count Rate (8.7+/-0.6)x10^3 s 0.0129+/-0.0025 count/s (4.8+/-0.2)x10^5 s 0.0045+/-0.0011 count/s (1.1+/-0.01)x10^6 s 0.0065+/-0.0025 count/s (1.4+/-0.07)x10^6 s 0.0083+/-0.0018 count/s We find that this source is now at a count rate consistent with that of our first observation on T0+1 day at the 1.5 sigma level. The chance probability for the source being steady is about 0.015, indicating that it is variable, but it is not decaying as expected for a GRB. We conclude that this source is not the afterglow of GRB 110825A. Thus, no afterglow was detected by XRT for this burst. We note that the variability of this X-ray counterpart in the last two weeks suggests that it may be a background AGN. The updated results of the XRT-team automatic analysis are available at .
GCN 12403 table
GRB_name GRB110825A
GCN_number 12403
Detection_method GROND
Circular_text TITLE: GCN CIRCULAR NUMBER: 12403 SUBJECT: GRB 110825A: GROND Observations DATE: 11/09/28 13:13:39 GMT FROM: Vladimir Sudilovsky at MPE V. Sudilovsky, J. Greiner, A. Rau (All MPE Garching), and S. Klose (TLS Tautenburg) report on behalf of the GROND team: We observed the field of the IPN GRB 110825A (Hurley et al., GCN 12307) on 2011 August 29 at 08:55 UT (52hr post trigger) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPI/ESO telescope at La Silla Observatory (Chile). With an exposure time of 3000s we do not find any source within the XRT error circle (Zhang et al., GCN 12308). In particular, the object reported by Xu et al. (GCN 12311) is not detected with a 3-sigma limiting magnitude of r' ~ 24.5 calibrated against USNO B1. This is consistent with the non-detection reported by Zhao et al (GCN 12314) and suggests that the source must have faded by at least 0.9mag within the first 48hr after the trigger. The optical decline is in agreement with a similar decay by a factor of 3 seen in the XRT lightcurve between day 1 and day 5 (Zhang et al., GCN 12334). While this could suggest the source detected by Xu et al. to be the afterglow of GRB110825A, the very late re-brightening observed in X-rays (Zhang et al., GCN 12334) makes this interpretation unlikely. Further deep optical imaging and X-ray monitoring are encouraged to resolve the nature of this source. We thank Kim Page and Phil Evans for providing helpful details concerning the XRT observations of GRB 110825A.