GRB091117A

This page lists all entries on GRB091117A in GRBweb

Summary IPN GCN 10171 GCN 10172 GCN 10173 GCN 10174 GCN 10175 GCN 10176 GCN 10177 GCN 10178 GCN 10179 GCN 10180 GCN 10181 GCN 10182 GCN 10183 GCN 10184 GCN 10185 GCN 10186 GCN 10232 GCN 10292

Summary table
Variable Value Source
T0 17:44:29.513 UTC GCN_circulars,Konus-Wind Det
ra 30.9458° IPN
decl -16.9500° IPN
pos_error 5.00e-02° IPN
redshift 0.0960 GCN_circulars,Swift Other
GBM_located False
mjd 55152.73923047454 GCN_circulars,Konus-Wind Det
IPN table
GRB_name GRB091117A
ra 30.9458°
decl -16.9500°
pos_error 5.00e-02°
GCN 10171 table
GRB_name GRB091117A
GCN_number 10171
Detection_method IPN Triangulation
ra 30.9450°
decl -16.9440°
Circular_text TITLE: GCN CIRCULAR NUMBER: 10171 SUBJECT: GRB 091117A Detected in ground analysis of BAT data and IPN triangulation DATE: 09/11/18 20:41:05 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (GSFC/CRESST), V. Pal'shin (Ioffe Inst.), K. Yamaoka (Aoyama Gakuin U.), P. Evans (U. Leicester) on behalf of the Swift-BAT, Konus-Wind, and Suzaku-WAM teams The Suzaku WAM alerted the IPN to a short hard burst that occurred at 17:44:29 UT on November 17th. The burst was seen in detector rates with Suzaku, Konus-Wind, INTEGRAL SPI ACS, and Swift-BAT. A source was found in ground analysis of BAT data (trigger 376211) at 12% coding. The BAT ground position was RA, Dec 30.945, -16.944, which is RA (J2000) 02h 03m 46.9s Dec (J2000) -16d 56' 38.0" with an estimated 90% containment radius of 2.6 arcmin. As seen in BAT, the burst had a weak precursor at T0, and the main spike at T+2.7 sec. The precursor was about 0.12 sec and the main spike was about 0.4 seconds long. The BAT peak count rate was about 700 counts/0.064 sec in the 15-350 keV band. There is an AGN 2.5 arcmin from this position, 2MASX J02035665-1656585 at z = 0.092. The BAT position is inside the error box of a triangulation performed using Konus-Wind, BAT, Suzaku-WAM, and INTEGRAL-SPI-ACS data. A Swift TOO observation has been requested and approved.
GCN 10172 table
GRB_name GRB091117A
GCN_number 10172
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10172 SUBJECT: GRB 091117: OSN I-band observations DATE: 09/11/18 23:37:29 GMT FROM: Javier Gorosabel at IAA-CSIC V. Casanova (OSN), A.J. Castro-Tirado (IAA-CSIC), A. de Ugarte Postigo (INAF/OAB), J. Gorosabel (IAA-CSIC), report on behalf of a larger collaboration: "We carried out I-band observations of the GRB 091117 error box (Cummings et al., GCNC 10171) with the 1.5m OSN telescope. The observations were performed on Nov 18.895-18.958 UT (27.7-29.3 hours post GRB). Visual comparison with the DSS does not reveal any new source in the error box brighter than I~20.5."
GCN 10173 table
GRB_name GRB091117A
GCN_number 10173
Detection_method Swift-XRT Other
ra 30.9723°
decl -16.9752°
Circular_text TITLE: GCN CIRCULAR NUMBER: 10173 SUBJECT: GRB 091117: XRT source coincident with a DSS galaxy DATE: 09/11/19 04:56:34 GMT FROM: Edo Berger at Harvard E. Berger (Harvard) reports: "Inspection of Swift/XRT observations of the short GRB 091117 (GCN #10171) reveals an X-ray source coincident with an extended object in DSS images. The DSS object (APMUKS B020129.84-171252.3) is located at the following coordinates (J2000): RA = 02:03:53.35 DEC = -16:58:30.6 Optical observations are in progress."
GCN 10174 table
GRB_name GRB091117A
GCN_number 10174
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 10174 SUBJECT: GRB 091117: Magellan optical observations DATE: 09/11/19 06:06:15 GMT FROM: Edo Berger at Harvard E. Berger (Harvard) and J. Mulchaey (OCIW) report: "We obtained optical r-band observations of the BAT error circle of GRB 091117 (GCN #10171) with IMACS on the Magellan/Baade 6.5-m telescope starting on 2009 Nov 19.06 UT. A comparison to DSS images reveals no new sources brighter than the DSS limit of about 21 mag. The galaxy coincident with the XRT source within the BAT error circle (GCN #10173) has a face-on spiral morphology. We find a single apparent point source coincident with one of the spiral arms. This object may be the optical afterglow of GRB091117 or an unrelated bright HII region. Additional observations are planned to determine if the source exhibits fading behavior. An image of the galaxy is available from: http://www.cfa.harvard.edu/~eberger/GRB091117_Magellan.gif
GCN 10175 table
GRB_name GRB091117A
GCN_number 10175
Detection_method Konus-Wind Det
t_trigger 17:44:29.513 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 10175 SUBJECT: Konus-Wind observations of GRB 091117A DATE: 09/11/19 11:00:48 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 short hard GRB 091117A (localized by Swift-BAT and IPN, Cummings et al., GCN 10171) triggered Konus-Wind at T0=63869.513 s UT (17:44:29.513). The burst light curve consists of a single peak with a total duration of ~0.3 s. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB091117_T63869/ As observed by Konus-Wind the burst had a fluence of 1.9(-0.5, +0.7)x10-6 erg/cm2, and a 16-ms peak flux measured from T0 of 1.4(-0.4. +0.7)x10-5 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+0.256 s) can be fitted (in the 20 keV - 5 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.42(-0.41, +0.64), and Ep = 663(-225, +396) keV (chi2 = 29/23 dof). Fitting by GRB (Band) model yields the same alpha and Ep values with the high energy photon index beta = -9.4 (< -1.9). All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.
GCN 10176 table
GRB_name GRB091117A
GCN_number 10176
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10176 SUBJECT: GRB 091117: Gemini-North spectroscopy of DSS galaxy DATE: 09/11/19 11:01:41 GMT FROM: Ryan Chornock at UC Berkeley R. Chornock and E. Berger (Harvard) report: We obtained spectra of the DSS galaxy coincident with the XRT source (GCN 10173) seen in the Swift observations of the short GRB 091117 (GCN 10171) using GMOS on Gemini-North. A pair of 1800s exposures using the R400 grating were taken starting at 07:27 UT on Nov. 19. Numerous emission lines are present at z=0.096. The slit was aligned through both the nucleus and the point source on the spiral arm (GCN 10174). The off-nuclear point source exhibits the high-equivalent-width nebular emission lines expected of an H II region and is therefore unlikely to be related to the afterglow of GRB 091117. In addition, the nuclear spectrum shows a broad component to the H-alpha line (FWHM ~ 1670 km/sec), indicative of an AGN. The AGN could also be responsible for the observed X-ray emission.
GCN 10177 table
GRB_name GRB091117A
GCN_number 10177
Detection_method Swift Other
ra 30.9724°
decl -16.9749°
redshift 0.0960
Circular_text TITLE: GCN CIRCULAR NUMBER: 10177 SUBJECT: GRB 091117: Swift XRT refined analysis DATE: 09/11/19 15:58:16 GMT FROM: Valerio D'Elia at INAF-OAR V. D'Elia, G. Stratta, M. Perri (ASDC), P.A. Evans and M.R. Goad (U. Leicester), J. Cummings (GSFC/CRESST), S. Campana (INAF-OAB) report on behalf of the Swift-XRT team: We have analysed 3.85 ks of XRT data for GRB 091117 (Cummings et al. et al. GCN Circ. 10171), from 96765 s to 119.4 ks after the Suzaku trigger. The data are entirely in Photon Counting (PC) mode. Two sources are detected at the edge of the BAT error circle. Source #1: using 722 s of XRT Photon Counting mode data and 1 UVOT images, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 30.97240, -16.97490 deg which is equivalent to: RA (J2000): 02 03 53.38 Dec (J2000): -16 58 29.8 with an uncertainty of 3.6 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). The source is at a count rate level of (4.8+/-1.4)e-3 counts/s. The light curve does not allow us to assess if the source is fading. This source has been reported by Berger et al. (GCN Circ. 10173) to be coincident with the DSS galaxy APMUKS B020129.84-171252.3 at redshift z=0.096 (Chornock & Berger 2009, GCN Circ. 10176) We can't distinguish if this is nuclear emission from the AGN discussed by Berger et al. (GCN Circ. 10176) Source #2: the other source has a count rate level of (2.7+/-1.1)e-3 counts/s and is at RA, Dec= 30.988333, -16.948583 deg which is equivalent to RA (J2000): 02 03 57.2 Dec(J2000): -16 56 54.9 with an uncertainty of 7.7 arcsec (radius, 90% confidence). The light curve does not allow us to assess if the source is fading. We note that there is a known source (2MASX J02035665-1656585 at z=0.096220) located 8.8 arcsec from Source #2. Further observations are planned for this field. This circular is an official product of the Swift-XRT team.
GCN 10178 table
GRB_name GRB091117A
GCN_number 10178
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10178 SUBJECT: GRB091117: Gemini South Observations DATE: 09/11/19 16:17:09 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko, J. S. Bloom, D. A. Perley (UC Berkeley) report on behalf of a larger collaboration: We have imaged the field of GRB091117 (Cummings et al., GCN 10171) with the Gemini Multi-Object Spectrograph on the 8 m Gemini South telescope beginning at 7:07 UT on 19 November (~ 37 hours after the burst trigger time). Observations were conducted in the Sloan g', r', and i' filters under poor seeing conditions (~ 2" FWHM). We find no new point sources at the location of either candidate X-ray afterglow (Berger, GCN 10173; D'Elia et al., GCN 10177). The limiting magnitude of our images is g' >~ 24 mag for isolated point sources; however we note that both XRT positions fall close to nearby galaxies and are contaminated by galaxy light. The galaxy system near source 2 appears to be highly disturbed, possibly indicative of recent merger activity.
GCN 10179 table
GRB_name GRB091117A
GCN_number 10179
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10179 SUBJECT: GRB 091117: Evidence for Variability of XRT Source #1 DATE: 09/11/19 16:49:49 GMT FROM: Derek Fox at PSU D. B. Fox (Penn State) reports: "Analysis of the first 3.85 ks of Swift XRT exposure (D'Elia et al., GCN 10177) on the field of GRB 091117 (Cummings et al., GCN 10171), as reduced via standard XRT pipeline processing, yields a total of 13 photons from Source #1 (Berger, GCN 10173) and 7 photons from Source #2 (D'Elia et al., GCN 10177). The resulting distribution of photon arrival times for Source #1 is inconsistent with a constant count rate at roughly 93% confidence, according to a single-sample KS test, suggesting fading or variable behavior of this X-ray source. The maximum deviation from a constant count rate model occurs after 35% of the integrated exposure, when 9 of 13 photons (70% of total counts) have been collected. The same test applied to the arrival times for Source #2 indicates consistency with a constant count rate (p-value of 0.90), however, the sensitivity of the test is more strongly limited by photon statistics in this case, such that we would not expect fading/variability at the level suggested in Source #1 to be apparent in Source #2, even if present."
GCN 10180 table
GRB_name GRB091117A
GCN_number 10180
Detection_method Swift-BAT Det
ra 30.9450°
decl -16.9440°
Circular_text TITLE: GCN CIRCULAR NUMBER: 10180 SUBJECT: GRB 091117 BAT refined analysis DATE: 09/11/19 19:18:16 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-0.16 to T+10 sec, we report further analysis of BAT/IPN GRB 091117 (trigger #376211) (Cummings, et al., GCN Circ.# 10171). The BAT ground-calculated position is as reported before, RA, Dec = 30.945, -16.944, which is RA (J2000) 02h 03m 46.9s Dec (J2000) -16d 56' 38.0" with an uncertainty of 2.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 12%. The mask-weighted light curve shows two peaks. The first is a weak spike at T+0 lasting for 0.15 sec. The second is the main spike at T+2.7 lasting for 0.4 sec. T90 (15-350 keV) is 0.43 +- 0.05 sec (estimated error including systematics). There is an indication of possible extended-time soft emission in the mask-weighted image covering ~1 minute in the 15-50 keV band following the burst (2.6 sigma). There is no indication of a persistent source in the BAT energy band at this position at other times. The time-averaged spectrum from T-2.5 to T+3.2 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.8 +- 0.3. The fluence in the 15-150 keV band is 3.5 +- 1.2 x 10-7 erg/cm2**. The 1-sec peak photon flux measured from T+2.3 sec in the 15-150 keV band is 2.5 +- 0.5 ph/cm2/sec. All the quoted errors are at the 90% confidence level. Because of the ground-detected nature of this burst, the usual automated data products are not currently available.
GCN 10181 table
GRB_name GRB091117A
GCN_number 10181
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10181 SUBJECT: GRB 091117: Swift-XRT observations DATE: 09/11/19 23:47:45 GMT FROM: Matteo Perri at ISAC/ASDC V. D'Elia, M. Perri (ASDC), J. Cummings (GSFC/CRESST) report on behalf of the Swift-XRT team: We have analysed further 4.0 ks of XRT data for GRB 091117 (Cummings et al. GCN Circ. 10171), from 161.3 ks to 172.4 ks after the trigger. The data are entirely in Photon Counting (PC) mode. We found that Source #1 (Berger, GCN Circ. 10173; D'Elia et al., GCN Circ. 10177; Fox, GCN Circ. 10179) is detected with a count rate of (1.9+/-0.9)e-3 cts/s, thus showing some evidence of fading with respect to the first Swift follow-up observation (errors are given at the 1-sigma level). We note that the photon statistics is low and further observations are needed to firmly assess that this source is the X-ray afterglow of the burst. Source #2 (D'Elia et al., GCN Circ. 10177; Fox, GCN Circ. 10179) is instead not detected. The derived 3-sigma upper limit value on its count rate, ~3.3e-3 cts/s, does not allow to constrain the temporal behavior of this source. This circular is an official product of the Swift-XRT team.
GCN 10182 table
GRB_name GRB091117A
GCN_number 10182
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 10182 SUBJECT: GRB 091117: VLA radio observations DATE: 09/11/20 04:08:09 GMT FROM: Edo Berger at Harvard E. Berger and W. Fong (Harvard) report: "We imaged the BAT error circle of the short GRB 091117 (GCN #10171) with the VLA at a frequency of 8.46 GHz starting on 2009 Nov 20.07 UT. In the 1 hour observation only a single source is detected within the BAT error circle, in coincidence with the galaxy near XRT Source #2 (GCNs #10177,10178). However, inspection of the NRAO VLA Sky Survey (NVSS) reveals a coincident archival source, indicating that this is not the afterglow of GRB 091117. No other sources are detected within the BAT error circle to a 3-sigma limit of about 120 microJy."
GCN 10183 table
GRB_name GRB091117A
GCN_number 10183
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 10183 SUBJECT: GRB 091117: 2nd epoch of Magellan optical observations DATE: 09/11/20 06:00:05 GMT FROM: Edo Berger at Harvard E. Berger (Harvard) and I. Momcheva (OCIW) report: "We obtained a second set of optical r-band observations of the BAT error circle of GRB 091117 (GCN #10171) with IMACS on the Magellan/Baade 6.5-m telescope starting on 2009 Nov 20.03 UT. A comparison to our first epoch of Magellan observations (GCN #10174) reveals no variable sources within the BAT error circle or in coincidence with the two XRT sources (GCNs #10173,10177,10181) to a limit of r~24 mag. The point source identified as an HII region (GCN #10176) has not varied in brightness. Further analysis is in progress."
GCN 10184 table
GRB_name GRB091117A
GCN_number 10184
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10184 SUBJECT: GRB 091117A: Swift/UVOT followup observations DATE: 09/11/20 11:32:17 GMT FROM: Alice Breeveld at MSSL-UCL A. Breeveld (MSSL/UCL), M. De Pasquale (MSSL/UCL) and J. R. Cummings (GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 091117A 96767s (~27 hours) after the BAT trigger (Cummings et al., GCN Circ. 10171). The galaxy described by Berger and Mulchaey (GCN Circ. 10174) as being a possible host, is clearly seen as an extended object in the UVOT data. There is no evidence of a fading source at either of the two XRT source positions (D'Elia et al., GCN Circ. 10177) when compared with data taken ~47 hours after the burst. In the case of source 1, which is coincident with the spiral galaxy, we checked for fading using an aperture of 2" at the refined XRT position as well as using an aperture of 8" to contain the whole galaxy. Magnitudes measured with a non-standard 8" aperture to include the whole galaxy, using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627), for the initial summed exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 97197 113850 875 17.56 0.01 v 109296 109642 340 17.05 0.06 u 96767 119064 2614 17.60 0.02 Upper limits (3 sigma) obtained at the position of source 2 (D'Elia et al., GCN Circ. 10181) are as follows: white 97197 113850 875 21.89 (UL) v 109296 109642 340 19.72 (UL) u 96767 119064 2614 21.52 (UL) None of the values quoted above are corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).
GCN 10185 table
GRB_name GRB091117A
GCN_number 10185
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 10185 SUBJECT: GRB 091117: TNG optical observations DATE: 09/11/21 01:24:23 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo (INAF-OAB), L.A. Antonelli (INAF-OAR), A. de Ugarte Postigo (INAF-OAB), A.J. Castro-Tirado (IAA-CSIC), J. Gorosabel (IAA-CSIC), E. Palazzi (IANF-IASFBo), S. Covino (INAF/OAB), J.M. de Leon Cruz, (IAA-CSIC), C. Padilla (TNG) report: We observed the field of GRB 091117 (Cummings et al. GCN 10171) with the Italian 3.6m TNG telescope, sited in Canary Islands (Spain) with the DOLORES camera in imaging mode on Nov 19.995 UT. Observations were carried out in V, R and I band. We compared our 900 s I-band image with the one obtained in the same band with the 1.5m OSN telescope on Nov 18.9 UT (Casanova et al., GCN 10172). Image subtraction performed with the ISIS package does not show any variable source in the overlap region covered by the two images (about 90% of the BAT error circle; Sakamoto et al, GCN 10180). In particular we note that no variability is detected for XRT source #1 (Berger, GCN. 10173; D'Elia et al., GCN 10177; Fox, GCN 10179) while no conclusion can be drawn for XRT source #2 (D'Elia et al., GCN 10177; Fox, GCN 10179) because it is saturated in the TNG image. An image showing the result of image subtraction is available here: http://www.brera.inaf.it/utenti/davanzo/grb/GRB091117_subtraction.jpg The 3sigma limiting magnitudes are I~22.9 and I~23.6 for the OSN and TNG images respectively.
GCN 10186 table
GRB_name GRB091117A
GCN_number 10186
Detection_method Suzaku WAM Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 10186 SUBJECT: GRB 091117A: Suzaku WAM observation of the prompt emission DATE: 09/11/22 07:30:19 GMT FROM: Hidenori Hayasi at Miyazaki U H. Hayashi, N. Ohmori, A. Daikyuji,E. Sonoda, K. Kono, K. Noda, Y. Nishioka, M. Yamauchi (Univ. of Miyazaki) T. Sugasahara, M. Tashiro, Y. Terada, A. Endo, K. Onda, W. Iwakiri (Saitama U.), S. Sugita(Nagoya U.), K. Yamaoka (Aoyama Gakuin U.), M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA), Y. E. Nakagawa, T. Tamagawa (RIKEN), N. Ohmori, A. Daikyuji, E. Sonoda, K. Kono, H. Hayashi, K. Noda, Y. Nishioka, M. Yamauchi (Univ. of Miyazaki), N. Vasquez (Tokyo Tech.), Y. Urata, H.M Lin (NCU), Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), S. Hong (Nihon U.), on behalf of the Suzaku WAM team, report The short GRB 091117A (Swift/BAT Detected in ground analysis ; Cummings et al., GCN 10171) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 2009-11-17 17:44:25.253 UT (=T0). The observed light curve shows a single peak starting at T0 s, ending at T0+1 s with a duration (T90) of about 0.4 seconds. The fluence in 100 - 1000 keV was 1.54 (-0.26/+0.25) x10^-6 erg/cm^2. The 1-s peak flux measured from T0 s was 2.78 (-0.30,+0.37) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0 s to T0+1 s is well fitted by a single power-law with a photon index of 1.29 (-0.13,+0.13) (chi^2/d.o.f. = 42/33). All the quoted errors are at statistical 90% confidence level, in which the 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 10232 table
GRB_name GRB091117A
GCN_number 10232
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 10232 SUBJECT: GRB 091117: Chandra Observations DATE: 09/12/02 19:36:40 GMT FROM: Derek Fox at PSU D. B. Fox (Penn State) and E. Berger (Harvard) report: "We observed the Swift/BAT localization region for GRB 091117 (Cummings et al., GCN 10171; Sakamoto et al., GCN 10180) with the Chandra X-ray Observatory + ACIS, positioned at the ACIS-S3 aimpoint, in a 20.1 ksec integration with mean epoch Nov 21.85 UT, 4.1 days after the burst trigger. Analysis of these data reveals the presence of nine X-ray sources within and near the BAT localization region, including the two X-ray sources identified in previous Swift XRT observations (Berger, GCN 10173; D'Elia et al., GCN 10177). Comparison to deep optical imaging of the region from Magellan (Berger & Mulchaey, GCN 10174; Berger & Momcheva, GCN 10183) reveals point-like (nuclear, stellar, or unresolved galactic) optical counterparts to all but three of these sources: # CXOU J Sigma Cts Unc Comments ========================================================== 1 020353.36-165830.0 54.0 119 11 XRT-1; Nuclear 2 020356.65-165659.1 44.5 101 10 XRT-2; Nuclear 3 020353.68-165428.1 14.7 34.9 6.5 Stellar 4 020338.35-165547.3 8.7 23.0 5.0 Stellar 5 020347.45-165927.6 6.2 13.4 3.7 (not imaged) 6 020342.46-165706.7 4.8 9.7 3.2 Stellar 7 020345.74-165817.1 4.2 8.7 3.0 Near galaxy 8 020345.21-165818.2 3.8 7.7 2.8 Stellar 9 020349.61-165430.5 3.7 7.6 2.8 No counterpart ========================================================== The table above provides source names/coordinates (J2000) as determined from the Chandra astrometric solution, the significance of detection in "wavdetect" analysis over the 0.3-8.0 keV bandpass, and estimated counts and uncertainties (0.3-8.0 keV) for each source. The nature of the optical counterpart, if any, is also provided. We note that the two brightest X-ray sources, also observed by Swift, are coincident to within <1 arcsec with the active nuclei of the two brightest galaxies in the region: Chandra source #1 (XRT-1) with the active nucleus of the face-on spiral galaxy at z=0.096 (Chornock & Berger, GCN 10176), and Chandra source #2 (XRT-2) with the active nucleus of 2MASX J02035665-1656585 at z=0.092. Source #1 appears (2.8-sigma confidence) to have faded since the first epoch of Swift observations, consistent with inferences from Swift XRT data (Fox, GCN 10179); however, the coincidence of sources #1 and #2 with AGN suggests that neither of these objects is associated with GRB 091117. Chandra source #7 is notable for being located 2.4 arcsec from the center of an edge-on galaxy that is resolved in our Magellan imaging."
GCN 10292 table
GRB_name GRB091117A
GCN_number 10292
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 10292 SUBJECT: GRB 091117: Swift-XRT late time observations DATE: 09/12/23 16:17:58 GMT FROM: Valerio D'Elia at INAF-OAR V. D'Elia, G. Stratta, M. Perri (ASDC), J. Cummings (GSFC/CRESST) report on behalf of the Swift-XRT team: Swift-XRT has observed the field of GRB 091117 about one month after the burst (Cummings et al. GCN Circ. 10171). The data set consists of two further observations, 9.7 ks and 9.2 ks, from 32.8 to 34.2 days after the trigger. The data are entirely in Photon Counting (PC) mode. We found that Source #1 (Berger, GCN Circ. 10173; D'Elia et al., GCN Circ. 10177; Fox, GCN Circ. 10179, D'Elia et al., GCN Circ 10181) is still detected with a count rate of (2.95+/-0.70)e-3 cts/s (first observation) and (3.42+/-0.75)e-3 cts/s (second observation), thus showing no evidence of fading with respect to the first Swift follow-up observations. Thus evidence of possible fading of Source #1, reported in Fox (GCN Circ. 10179), D'Elia et al. (GCN Circ.10181) and Fox & Berger (GCN Circ. 10232), is not confirmed by these measurements. Source #2 (D'Elia et al., GCN Circ. 10177; Fox, GCN Circ. 10179, D'Elia et al., GCN Circ 10181) is also detected, and the derived count rate is (2.03+/-0.55)e-3 cts/s (first observation) and (1.85+/-0.54)e-3 cts/s (second observation). No evidence of a fading behavior is found for this source either. All quoted errors are given at the 1-sigma level. In view of these XRT observations, we can safely conclude that neither source is the X-ray afterglow of GRB091117. This circular is an official product of the Swift-XRT team.