//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16763 SUBJECT: GRB 140903A: Swift detection of a possible burst DATE: 14/09/03 15:56:04 GMT FROM: David Palmer at LANL J. R. Cummings (NASA/UMBC), D. N. Burrows (PSU), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 15:00:30 UT, BAT triggered on a possible GRB at RA, dec = 238.036, +27.578 (J2000). However, due to a TDRSS telemetry gap, no further data is available at this time. No XRT source was detected in 90 s of downlinked data taken approximately 1.5ks after the trigger time. We are waiting for the full dataset to detect and localise the XRT counterpart. No UVOT data is available at this time. The full data set will be available following the next ground pass. Burst Advocate for this burst is J. R. Cummings (jayc AT milkyway.gsfc.nasa.gov). 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.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16764 SUBJECT: GRB 140903A: Preliminary Swift/XRT localization DATE: 14/09/03 17:26:47 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT J. A. Kennea (PSU) and J. R. Cummings (NASA/UMBC) report on behalf of the Swift/XRT Team: Swift/XRT began observing the position of GRB 140903A at 15:01:29UT, approximately 59 seconds after the BAT trigger (GCN #16763). In preliminary data we find an uncatalogued fading source at the following location: RA/Dec(J2000) = 238.01597, 27.603287, which is equivalent to: RA(J2000) = 15h 52m 3.83s, Dec(J2000) = 27d 36m 11.8s, with an estimated uncertainty of 10 arc-seconds radius (90% confidence). The light-curve appears to show rapid fading, consistent with this X-ray source being a GRB afterglow. We will publish an improved position for this burst when more data become available. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16765 SUBJECT: GRB 140903A: Confirmed Swift detection of a short burst DATE: 14/09/03 17:32:26 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (NASA/UMBC) reports on behalf of the Swift Team: At 15:00:30 UT, BAT triggered on GRB 140903A. The onboard BAT localization was at RA, dec = 238.036, +27.578, which is RA (J2000) 15h 52m 08.6s Dec (J2000) +27d 34' 41" with an estimated 90% uncertainty radius of 3 arcmin. The BAT lightcurve shows a single peak about 0.45 seconds long. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16766 SUBJECT: GRB 140903A: Coincident galaxy cluster in archival images DATE: 14/09/03 18:53:21 GMT FROM: Derek Fox at PSU Derek B. Fox (PSU) and J. R. Cummings (NASA/UMBC) report: "The BAT (Cummings, GCN 16765) and XRT (Kennea & Cummings, GCN 16764) localizations of GRB 140903A (Cummings et al., GCN 16763) are located within 2.5' (<0.2 Mpc projected) of the center of the galaxy cluster NSC J155202+273349, as cataloged by the Northern Optical Cluster Survey (Gal et al. 2003, AJ, 125, 2064). While the photometric redshift for the cluster is provided as z=0.2955 in the catalog, four of the five SDSS-resolved galaxies nearest the XRT position have spectroscopic redshifts (SDSS and 2MASX surveys, as retrieved from the NASA Extragalactic Database) within the range z=0.074 +/- 0.001. In particular, the two nearest galaxies with known redshifts are SDSS J155208.34+273631.8 at z=0.073 (1.05' distance) and 2MASX J15520787+2735016 at z=0.075 (1.47' distance). Given past associations (and proposed associations) of short bursts with evolved galaxies and galaxy clusters at z<~0.3 we consider the presence of this coincident galaxy cluster at z~0.074 suggestive." This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16767 SUBJECT: GRB 140903A: Swift-XRT refined Analysis DATE: 14/09/03 20:57:43 GMT FROM: Massimiliano de Pasquale at IASF-Palermo M. De Pasquale, A. Maselli (IASF-Palermo), J. R. Cummings (NASA/UMBC) reports on behalf of the Swift-XRT team: We have analysed 2.9 ks of XRT data for GRB 140903A (Cummings et al. GCN Circ. 16763), from 74 s to 7.3 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. Using 3407 s of PC mode data and 7 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 238.01361, +27.60259 which is equivalent to: RA (J2000): 15h 52m 03.27s Dec(J2000): +27d 36' 09.3" with an uncertainty of 1.7 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=0.21 (+/-0.08). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.71 (+0.21, -0.20). The best-fitting absorption column is 1.2 (+0.7, -0.6) x 10^21 cm^-2, in excess of the Galactic value of 3.3 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 4.0 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.2 (+0.7, -0.6) x 10^21 cm^-2 Galactic foreground: 3.3 x 10^20 cm^-2 Excess significance: 2.5 sigma Photon index: 1.71 (+0.21, -0.20) If the light curve continues to decay with a power-law decay index of 0.21, the count rate at T+24 hours will be 0.11 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.5 x 10^-12 (5.3 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00611599. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16768 SUBJECT: GRB 140903A: Swift-BAT refined analysis DATE: 14/09/04 01:33:48 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings, N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-61 to T+159 sec from the recent telemetry downlink, we report further analysis of BAT GRB 140903A (trigger #611599) (Cummings, et al., GCN Circ. 16763). The BAT ground-calculated position is RA, Dec = 238.021, 27.608 deg which is RA(J2000) = 15h 52m 05.0s Dec(J2000) = +27d 36' 27.6" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 83%. The mask-weighted light curve shows a single FRED peak. T90 (15-350 keV) is 0.30 +- 0.03 sec (estimated error including systematics). The time-averaged spectrum from T-0.01 to T+0.35 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.99 +- 0.12. The fluence in the 15-150 keV band is 1.4 +- 0.1 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T-0.33 sec in the 15-150 keV band is 2.5 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. This burst was short but we note that it was not particularly hard. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/611599/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16769 SUBJECT: GRB140903A: Discovery Channel Telescope Optical Detection DATE: 14/09/04 05:28:27 GMT FROM: John Capone at UMD J. Capone (UMD), V. Toy (UMD), S.B. Cenko (NASA-GSFC), A. Cucchiara (NASA-GSFC), E. Troja (NASA-GSFC), A. Kutyrev (NASA-GSFC), S. Veilleux (UMD), and S. Gezari (UMD) report on behalf of a larger collaboration: We observed the field of GRB140903A (Cummings et al., GCN 16763) with the Large Monolithic Imager (LMI) on the 4.3m Discovery Channel Telescope (DCT) at Happy Jack, AZ. We observed in r' for a total of 600 seconds beginning at 2014-09-04 03:10 UTC (approximately 12 hours after the Swift trigger). A source is clearly detected at the location of the x-ray afterglow (De Pasquale et al, GCN 16767). Using nearby point sources from SDSS for calibration, we measure a preliminary magnitude of r' = 20.2 +/- 0.3. This value is not corrected for Galactic extinction in the direction of the GRB. We also note the presence of a 9th magnitude star ~10 arcseconds from the afterglow candidate. We thank the staff of the Discovery Channel Telescope for assistance with these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16770 SUBJECT: GRB 140903A: P60 Optical Observations DATE: 14/09/04 06:09:46 GMT FROM: S. Bradley Cenko at NASA/GSFC S. B. Cenko (NASA/GSFC) and D. A. Perley (Caltech) report on behalf of a larger collaboration: We observed the field of the Swift short GRB 140903A (Cummings et al., GCN 16763) with the robotic Palomar 60 inch telescope. Observations were obtained in the g', r', and i' filters beginning at 3:13 UT on 4 September 2014 (12.2 hr after the Swift trigger time). We detect a faint source at the northern edge of the revised XRT error circle (De Pasquale et al., GCN 16767), with (J2000.0) coordinates RA: 15:52:03.28 Dec: +27:36:10.7 and an estimated uncertainty of ~ 0.5" in each coordinate. Visual comparison reveals that this is the same source identified by Capone et al. in the Discovery Channel Telescope imaging reported in GCN 16769. Using nearby point sources from SDSS for calibration, we estimate a magnitude of r' = 20.0 for the source at this time. We caution, however, that the photometry is strongly affected by the presence of the nearby bright star. We estimate an uncertainty of ~ 0.5 mag, but accurate photometry will need to await a more thorough analysis. Since our observations overlap with those reported by Capone et al., we cannot confirm any variability in this object. Inspection of the archival SDSS images does not reveal an obvious source at this location, but the images are strongly affected by the nearby bright star, and thus the depth may be insufficient for a meaningful comparison. We encourage additional follow-up to determine if this is indeed the optical afterglow of GRB 140903A. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16771 SUBJECT: GRB 140903A: Swift-BAT Spectral lag analysis DATE: 14/09/04 06:32:31 GMT FROM: Takanori Sakamoto at AGU T. Sakamoto (AGU), J. Norris (BSU), S. D. Barthelmy (GSFC), N. Gehrels (GSFC) report: We report the spectral lag analysis for GRB 140903A (GCN Circ. 16764 & 16765) based on the BAT data. Using 4-ms binned light curve, the spectral lag for the 50-100 keV to 100-350 keV bands is 16 +- 7 ms, and 21 +- 7 ms for the 15-25 keV to 50-100 keV bands. There is no evidence for extended emission. Those lag values are consistent with the short end of the long-burst lag distribution. Although the lag analysis suggests GRB 140903A is consistent with a long GRB population, a further observation is needed to understand the nature of this burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16772 SUBJECT: GRB 140903A: Swift/UVOT Upper Limits DATE: 14/09/04 10:35:34 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and J. R. Cummings (NASA/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 140903A 76 s after the BAT trigger (Cummings et al., GCN Circ. 16763). No optical afterglow consistent with the XRT position (De Pasquale et al. GCN Circ. 16767) or optical position given by Cenko et al. (GCN Circ. 16770), is detected in the initial UVOT exposures. The analysis is complicated by the wings of the bright star mentioned by Capone et al. (GCN Circ. 16767), and thus the upper limits should be treated with caution. 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 77 227 147 >20.01 u_FC 289 539 246 >17.4 white 77 17449 944 >21.0 v 618 29425 1322 >18.9 b 544 17228 1376 >20.0 u 289 23404 1138 >18.2 w1 1097 22967 1121 >18.4 m2 643 6613 255 >18.8 w2 5562 28728 1918 >18.6 The magnitudes in the table are not 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). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16774 SUBJECT: GRB 140903A: tentative spectroscopic redshift DATE: 14/09/04 14:30:39 GMT FROM: Antonino Cucchiara at NASA/GSFC A. Cucchiara (NASA-GSFC), S.B. Cenko (NASA-GSFC), D. A. Perley (Caltech), J. Capone (UMD), and V. Toy (UMD) report on behalf of a larger collaboration: On September 4.20 UT we observe the candidate afterglow of the short GRB 140903A (Cummings et al. GCN 16763, Kennea et al. GCN 16764, Capone et al. GCN 16769) with the Gemini-North telescope equipped with the GMOS camera. A set of 2x600s exposures were obtained in spectroscopic mode: our spectra covered the wavelength range 4000-8100 Angstroms at a resolution of R~1200. We clearly identify a strong absorption doublet feature at the observed wavelength 7954, 7965 Angstrom and a weak emission line at 6570 Angstrom. We tentatively interpret these features as NaID in absorption and H-beta line in emission at the common redshift of z=0.351. No other clear features are visible neither in emission nor in absorption, therefore we suggest this to be the redshift of the host galaxy of GRB 140903A. We thank the Gemini staff, in particular Jess Ball, for their prompt assistance with these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16776 SUBJECT: GRB 140903A: Pan STARRS images of the field DATE: 14/09/04 22:23:37 GMT FROM: Andrew S. Fruchter at STScI A.S. Fruchter reports: The field of GRB 140903A was observed on numerous occasions in multiple filters by the Pan STARRS survey. An object is visible at the location reported by Cenko et al. (GCN 16770) in the r, i, z and y filter stacks. The proximity of the object to a bright star makes accurate photometry extremely difficult. However, in the i and z bands, where the object is most clearly visible against the scattered light from the nearby star, I estimate magnitudes of 20.0 +/- 0.2 in both filters. This agrees well with that reported by Cenko et al in the r band., suggesting that this source is stable. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16777 SUBJECT: GRB 140903A: 6 GHz VLA detection DATE: 14/09/04 22:47:57 GMT FROM: Wen-fai Fong at U of Arizona W. Fong (U. Arizona) reports: "We observed the position of the short-duration GRB 140903A (Cummings et al., GCN 16763; GCN 16765) with the Karl G. Jansky Very Large Array (VLA) beginning on 2014 Sept 4.040 UT (9.70 hr post-burst) at a mean frequency of 6 GHz. In 1 hour of observations, we detect a ~0.11 mJy radio source at the position: RA(J2000) = 15:52:03.21 Dec(J2000) = +27:36:10.7 with an uncertainty of 0.3" in each coordinate. This position is coincident with the reported optical source (Capone et al., GCN 16769; Cenko et al., GCN 16770; Cucchiara et al., 16774; Fruchter, GCN 16776). Further observations are planned. We thank the VLA staff for quickly executing these observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16778 SUBJECT: GRB 140903A: MAXI/GSC upper limit DATE: 14/09/05 03:31:00 GMT FROM: Motoko Suzuki at RIKEN M. Serino (RIKEN), T. Sakamoto (AGU), N. Kawai (Tokyo Tech), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Morii, J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN), T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, D. Uchida (Osaka U.), H. Negoro, M. Nakajima, K. Fukushima, T. Onodera, K. Suzuki, T. Namba, M. Fujita, F. Honda (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, A. Kawagoe (Chuo U.), M. Yamauchi, Y. Morooka, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team: The MAXI/GSC scanned the field of GRB 140903A triggered by Swift BAT (Cumming et al. GCN Circ. 16763) at 15:00:42 (12 sec after the trigger) UT on 2014-09-03. The durations of the scan was 44 sec. No obvious source was detected by MAXI/GSC at the location of BAT. The 3 sigma upper limit of the scan derived by the MAXI/GSC data is 8.4 x 10^-10 erg/cm2/s (4-10 keV). This upper limit is roughly consistent with the power-law interpolation of the BAT prompt emission flux (T ~ 0-0.3 s) and the first XRT point (t ~ 100 s), assuming that the BAT spectrum (power-law with photon index 1.99, Palmer et al. GCN Circ. 16768) extends down to soft X-ray emission with no spectral break. It suggests that no strong soft extended emission was associated with this GRB (Sakamoto et al. GCN Circ. 16771). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16779 SUBJECT: GRB 140903A: ISON-Kislovodsk observations DATE: 14/09/05 04:11:18 GMT FROM: Alexei Pozanenko at IKI A. Pozanenko (IKI), A. Volnova (IKI), N. Polyakov (ISON), E. Romas (ISON), I. Molotov (KIAM), report on behalf of larger collaboration: We observed the field of GRB 140903A (Cummings et al., GCN 16763) with Santel-400AN telescope of ISON-Kislovodsk observatory starting on Sep. 03 (UT) 18:54:36. In the enhanced XRT position (De Pasquale et al., GCN 16767) we do not detect the object (Capone et al., GCN 16769; Cenko et al., GCN 16770; Fruchter, GCN 16776). A preliminary upper limit after subtraction of the nearby bright star is 16m. A formal upper limit of a point-like source in the image away of the bright nearby star is following Date UT start t-T0 Filter Exp. UL(3 sigma) (mid, days) (s) 2014-09-03 18:22:05 0.14057 None 100 18.6 The photometry is based on SDSS stars SDSS J155213.13+273321.7 R_Lupton 15.392 ± 0.013 SDSS J155218.31+273433.5 R_Lupton 14.792 ± 0.013 SDSS J155155,39+273948,9 R_Lupton 15.421 ± 0.013 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16781 SUBJECT: GRB 140903A: FTN observations DATE: 14/09/05 10:23:04 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy S. Dichiara, C. Guidorzi (U. Ferrara), J. Japelj (U. Ljubljana) on behalf of a large collaboration report: The 2-m telescope Faulkes Telescope North in Hawaii began observing Swift GRB 140903A (Cummings et al. GCN Circ 16763) on September 04 at 06:35:20 UT, i.e. ~15.6 hours after the BAT trigger, with the r' and i' filters. We detect the optical source reported by Capone et al. (GCN 16769), Cenko et al. (GCN 16770), Fruchter (GCN 16776) within an estimated magnitude of r'=20.4 +- 0.5. Given the measured values and relatively large uncertainties, nothing can be inferred on the possible fading. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16783 SUBJECT: GRB 140903A: NOT optical and NIR observations DATE: 14/09/05 14:11:50 GMT FROM: Dong Xu at DARK/NBI D. Xu (DARK/NBI), S. Geier (ESO), D. Malesani, J. P. U. Fynbo (DARK/NBI), J. Harmanen (NOT), A. J. Levan (U. Warwick), P. Jakobsson (U. Iceland) report on behalf of a large collaboration: We observed the field of the short GRB 140903A (Cummings et al., GCN 16763) using the 2.5m Nordic Optical Telescope (NOT) equipped with StanCam and NOTCam. We observed for a total of 20 and 30 min in the R- and H- bands, respectively. The middle times of the observations are 29.898 hr and 30.315 hr after the BAT trigger, respectively. The previously reported object (Capone et al., GCN 16769; Cenko et al., GCN 16770; Fruchter, GCN 16776; Dichiara et al., GCN 16781) is clearly detected in our R- and H-band stacked images. We found R=20.1+/-0.5 mag calibrated with nearby SDSS stars and H=16.1+/-0.3 mag calibrated with the nearby 2MASS stars. Note that a fuzzy source is present at the same position in the SDSS field, especially in z-band. Together with the pre- and post-burst observations, the optical brightness of the object either varies slowly or remains constant (see also Fruchter, GCN 16776), which implies that what we're observing in optical is basically the host galaxy of the burst. [GCN OPS NOTE(05sep14): Per author's request, the affilliation of SG was changed to ESO.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16784 SUBJECT: GRB 140903A: Possible optical variability DATE: 14/09/05 14:49:26 GMT FROM: Andrew Levan at U.of Leicester A.J. Levan (U. Warwick), S.B. Cenko, A. Cucchiara (NASA-GSFC), D.A. Perley (Caltech) report for a larger collaboration: "We observed the location of the short GRB 140903A (Cummings et al. GCN 16763, 16765) with Gemini-N beginning at 5 Sep 2014, 05:16 UT. At this epoch we obtained observations in iJ and K utilising GMOS-N and NIRI. The source reported by Capone et al. (GCN 16769) and Cenko et al. (GCN 1677) is well detected in all bands. A comparison between these images and the acquisition images taken on 4 Sept 2014 (Cucchiaria et al. GCN 16774) is indicative of a fading by 0.12 +/- 0.04 mag. An image subtraction shows a residual consistent with this fading, although both photometry and image subtraction are complicated by the presence of the nearby bright star. This decay is very slow in comparison to most GRB afterglows and implies a significant contribution from the underlying host galaxy, consistent with its pre-trigger detection (Fruchter GCN 16776, Xu et al. GCN 16783). We note that the source remains largely point like in our observation, and the centroid of the subtraction residual is offset only ~0.1" from the centre of the combined host+afterglow source." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16785 SUBJECT: GRB 140903A: Confirmation of Optical Fading from Discovery Channel Telescope DATE: 14/09/06 05:06:52 GMT FROM: S. Bradley Cenko at NASA/GSFC S. B. Cenko (NASA-GSFC), J. Capone, V. Toy (UMD), A. Cucchiara, E. Troja, A. Kutyrev (NASA-GSFC), S. Veilleux, and S. Gezari (UMD) report on behalf of a larger collaboration: We obtained additional r'-band imaging of the candidate optical afterglow (Capone et al., GCN 16769) of the Swift short burst GRB 140903A (Cummings et al., GCN 16763) with the Discovery Channel Telescope, beginning at 2:55 UT on 6 September 2014 (2.5 d after the Swift trigger). Performing digital image subtraction using our most recent epoch as a template, we detect significant fading in this source, confirming the results of Levan et al. (GCN 16784). Assuming no afterglow contamination in our latest epoch, we measure an afterglow brightness of r' = 21.7 at the time of our first DCT images (~ 12 hr after the Swift trigger). This suggests the early emission was heavily contaminated by the host galaxy, consistent with the results of Fruchter et al. (GCN 16776) and Xu et al. (16783). A figure showing our subtraction image can be found at: http://asd.gsfc.nasa.gov/Brad.Cenko/grb140903A_dct.pdf The detection of optical variability, together with a coincident radio detection (Fong, GCN 16777), confirm the host association of z = 0.351 for GRB 140903A (Cucchiara et al., 16774). We encourage additional follow-up (e.g., super/kilonova searches) to help clarify the nature of the progenitor system of this event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16813 SUBJECT: GRB 140903A: Chandra detection of the afterglow DATE: 14/09/10 21:26:39 GMT FROM: Takanori Sakamoto at AGU T. Sakamoto (AGU), E. Troja (GSFC/UMCP), N. Gehrels (GSFC), J. Norris (BSU), S. D. Barthelmy (GSFC), J. L. Racusin (GSFC), N. Kawai (Tokyo Tech), A. Fruchter (STScI) A Chandra ToO observation of a short GRB 140903A (Cummings et al., GCN Circ. 16763; Cummings et al., GCN Circ. 16765) started on September 6 08:54 UT (~2.7 days after the GRB trigger) for a total of 19.8 ksec. The X-ray afterglow was clearly detected at a position (RA, Dec) = (238.013519, +27.60303) which is equivalent to: RA (J2000) = 15 52 03.24 Dec (J2000) = +27 36 10.9 The 1-sigma statistical error is 0.05 and 0.04 arcsec on RA and Dec respectively. The systematic error of the Chandra aspect solution is 0.3 arcsec (radius, 68% containment; i.e, http://cxc.harvard.edu/cal/ASPECT/celmon/) which dominates the localization uncertainty. The Chandra location is consistent with the enhanced XRT position (De Pasquale et al., GCN Circ. 16767) and the reported NIR, optical and radio afterglow/host candidate (Capone et al., GCN Circ. 16769; Cenko et al., GCN Circ. 16785; Cenko et al., GCN Circ. 16770; Fruchter et al., GCN Circ. 16776; Fong, GCN Circ. 16777; Dichiara et al., GCN Circ. 16781; Xu et al. GCN Circ. 16783; Levan et al. GCN Circ. 16784). Our Chandra detection confirms the association of the reported NIR, optical and radio candidate to GRB 140903A. Further Chandra observations are planned. We would like to thank the Chandra operation team for rapidly approving and making this observation. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16815 SUBJECT: Possible radio detection of GRB 140903A with the GMRT DATE: 14/09/12 08:44:42 GMT FROM: Poonam Chandra at TIFR A. J. Nayana (NCRA-TIFR) and Poonam Chandra (NCRA-TIFR) report: We carried out the Giant Metrewave Radio Telescope (GMRT) observations of GRB 1400903A (Cummings et al. GCN 16763) in the 1390 MHz band on 2014 September 11.05 UT. We detect a 3.1-sigma source at the GRB position (Cenko et al. 16770) with a flux density of 102+/-33 uJy. This is most likely the radio afterglow of GRB 140903A. We are carrying out further observations to confirm this detection. We thank GMRT staff for making these observations possible.