//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17526 SUBJECT: GRB 150302A: Swift detection of a burst DATE: 15/03/02 05:56:18 GMT FROM: David Palmer at LANL A. Y. Lien (GSFC/UMBC), M. M. Chester (PSU), M. De Pasquale (INAF-IASFPA), A. Maselli (INAF-IASFPA), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 05:42:36 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150302A (trigger=633237). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 175.508, +36.827 which is RA(J2000) = 11h 42m 02s Dec(J2000) = +36d 49' 37" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single complex peak structure with a duration of about 30 sec. The peak count rate was ~800 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 05:44:17.5 UT, 100.9 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 175.5314, 36.8110 which is equivalent to: RA(J2000) = +11h 42m 7.54s Dec(J2000) = +36d 48' 39.6" with an uncertainty of 5.9 arcseconds (radius, 90% containment). This location is 88 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. UVOT took a finding chart exposure of 2 seconds with the White filter starting 109 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. Results from the 2.7'x2.7' sub-image are not available at this time. Results from the list of sources generated on-board are not available at this time. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Burst Advocate for this burst is A. Y. Lien (amy.y.lien AT 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: 17527 SUBJECT: GRB 150302A: NOT afterglow candidate DATE: 15/03/02 06:25:52 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC J.P.U. Fynbo (DARK/NBI), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), T. Kruehler (ESO), and M. Saajasto (NOT) report on behalf of a larger collaboration: We observed the field of GRB 150302A (Lien et al., GCN 17526) using the 2.5m Nordic Optical Telescope with AlFOSC. Observations starting at 05:59 UT (17 min after the GRB) reveal an optical counterpart within the XRT error box at coordinates 11:42:07.43 +36:48:38.9 (J2000.0), with a magnitude of r=22.3, calibrated against SDSS field stars. [GCN OPS NOTE(02mar15), Per author's request, MS was added to the author list.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17528 SUBJECT: GRB 150302A: UVOT Observations DATE: 15/03/02 07:08:01 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift/UVOT group: UVOT took a finding chart exposure of 150 seconds with the White filter starting 3435 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17529 SUBJECT: GRB 150302A: KAIT Optical Upper Limit DATE: 15/03/02 07:30:14 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift GRB 150302A (Lien et al., GCN 17526) starting at 05:44:50 UT, 134 s after the burst, under bright moon condition. First few images were useless until ~18 minutes after the burst. Observations were performed with an automatic sequence in the clear (roughly R), V, and I filters, and the exposure time was 20 s per image. We do not detect the afterglow candidate (Fynbo et al., GCN 17527) in our images, with a limiting magnitude of R~17.8 (calibrated to USNO B1.0) at a mid-time of 18.9 minutes after the burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17534 SUBJECT: GRB 150302A: Enhanced Swift-XRT position DATE: 15/03/02 20:22:36 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 637 s of XRT Photon Counting mode data and 1 UVOT images for GRB 150302A, 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 = 175.53116, +36.81107 which is equivalent to: RA (J2000): 11h 42m 7.48s Dec (J2000): +36d 48' 39.8" with an uncertainty of 3.3 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). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17535 SUBJECT: GRB 150302A: Swift-XRT refined Analysis DATE: 15/03/02 20:56:04 GMT FROM: Phil Evans at U of Leicester D.N. Burrows (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC) and A.Y. Lien report on behalf of the Swift-XRT team: We have analysed 11 ks of XRT data for GRB 150302A (Lien et al. GCN Circ. 17526), from 92 s to 28.9 ks after the BAT trigger. The data comprise 5 s in Windowed Timing (WT) mode (the first 7 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 17534). The light curve can be modelled with a power-law decay with a decay index of alpha=1.91 (+0.07, -0.06). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.3 (+0.8, -0.6). The best-fitting absorption column is 1.9 (+2.1, -1.6) x 10^21 cm^-2, in excess of the Galactic value of 1.8 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 3.1 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.9 (+2.1, -1.6) x 10^21 cm^-2 Galactic foreground: 1.8 x 10^20 cm^-2 Excess significance: 1.8 sigma Photon index: 2.3 (+0.8, -0.6) If the light curve continues to decay with a power-law decay index of 1.91, the count rate at T+24 hours will be 1.0 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.2 x 10^-15 (4.9 x 10^-15) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00633237. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17537 SUBJECT: GRB 150302A: MITSuME Okayama upper limits DATE: 15/03/02 23:43:49 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of MITSuME and OISTER collaboration: We observed the field of GRB 150302A (Lien et al., GCNC 17526) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory. The observation started on 2015-03-02 11:23:12 UT (~5.7 h after the burst). We could not detect the previously reported afterglow (Fynbo et al., GCNC 17527) in all the three bands. Three sigma upper limits of the OT are listed below. We used SDSS-DR8 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 0.27847 12:23:36 5880.0 >19.7 >19.8 >19.2 0.36250 14:24:37 6240.0 >20.2 >20.2 >19.5 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17538 SUBJECT: GRB 150302A: Swift/UVOT Upper Limits DATE: 15/03/02 23:45:02 GMT FROM: Margaret Chester at PSU M. M. Chester (PSU) and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 150302A 110 s after the BAT trigger (Lien et al., GCN Circ. 17526). No optical afterglow consistent with the optical candidate reported by Fynbo et al. (GCN Circ. 17527) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) are as follows. We report only the second finding chart (FC) exposure and subsequent exposures; the first finding chart exposure was too short (< 2 s) to be useful. Filter T_start(s) T_stop(s) Exp(s) UL (3-sigma) white_FC 3436 3585 147 >21.4 white 3436 11616 993 >22.1 v 5262 28248 1077 >21.0 b 3799 17368 1738 >22.2 u 3594 23030 2557 >21.9 w1 5672 22421 1960 >21.5 m2 5466 28871 1690 >22.4 w2 4210 27342 995 >21.4 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17539 SUBJECT: GRB 150302A, Swift-BAT refined analysis DATE: 15/03/03 04:01:52 GMT FROM: Amy Lien at GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), 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+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150302A (trigger #633237) (Lien, et al., GCN Circ. 17526). The BAT ground-calculated position is RA, Dec = 175.515, 36.852 deg which is RA(J2000) = 11h 42m 03.6s Dec(J2000) = +36d 51' 06.3" with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a weak single-peaked structure that starts at ~ T-1 s, peaks at ~T+3 s, and ends at ~T+20 s. T90 (15-350 keV) is 23.74 +- 8.79 sec (estimated error including systematics). The time-averaged spectrum from T-1.14 to T+28.23 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.69 +- 0.33. The fluence in the 15-150 keV band is 2.6 +- 0.6 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+2.61 sec in the 15-150 keV band is 0.4 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/633237/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17540 SUBJECT: GRB 150302A: Mondy optical upper limit DATE: 15/03/03 18:09:34 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Volnova (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), M. Eselevich (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 150302A (Lien et al., GCN 17526) with AZT-33IK telescope of Sayan observatory (Mondy). We obtained several images in R-filter on Mar., 02, starting (UT) 15:55:19. Within enhanced XRT error circle (Goad et al., GCN 17534) we do not detect any optical source. In particular, we do not detect the afterglow candidate (Fynbo et al., GCN 17527). Upper limit is following Date UT start t-T0 Filter Exp. UL(3sigma) (mid, days) (s) 2015-03-02 15:55:19 0.44045 R 43*60 21.6 The photometry is based on nearby SDSS DR9 stars SDSS9_id R(Lupton) J114204.20+364911.9 16.90 J114201.34+365107.3 19.45 J114159.81+365111.7 19.15 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17542 SUBJECT: GRB 150302A: BOOTES-2/TELMA upper limit DATE: 15/03/04 20:38:30 GMT FROM: Soomin Jeong at IAA-CSIC S. Jeong (IAA-CSIC & SKKU), M. Jelinek, J. C. Tello (IAA-CSIC) and A. J. Castro-Tirado (IAA-CSIC & ISA-UMA), on behalf of a larger collaboration, report: "The 60 cm BOOTES-2/TELMA robotic telescope (Malaga, Spain) automatically responded to the Swift trigger of GRB 150302A (Lien et al., GCN 17526). The first exposure started at 05:43:54 UT (78s after the trigger) and a sequence of 79 images was obtained (3s each, z filter). A median combined image revealed no credible optical source detection neither at the enhanced XRT error circle (Goad et al., GCN 17534) nor at the optical counterpart position (Fynbo et al., GCN 17527) down to 18.5 mag (3 sigma UL). It is calibrated against the SDSS z-field." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20000 SUBJECT: GRB 150302A: late-time imaging and optical afterglow confirmation DATE: 16/10/06 06:03:14 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani (DARK NBI and DTU Space), J.P.U. Fynbo (DARK/NBI), and T. Kruehler (MPE), report on behalf of a larger collaboration: We observed the field of GRB 150302A (Lien et al., GCN 17526) with the Nordic Optical Telescope (NOT) equipped with the ALFOSC imaging camera. Observations (4x300 s exposure) were carried out in the SDSS r filter, at a mean epoch 2016 Jun 23.94 UT (1.3 years after the GRB). At the location of the optical afterglow candidate (Fynbo et al., GCN 17527), we detect no source down to a limiting magnitude of r = 23.5, calibrated against nearby SDSS stars. By comparing with our early epoch, we conclude that the source has faded by more than 1 mag. Together with the positional consistency with the enhanced XRT location (Goad et al., GCN 17534), we can thus now confirm it as the optical afterglow of GRB 150302A. We acknowledge excellent support from the NOT observing staff, in particular John Telting.