//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7416 SUBJECT: GRB 080315: Swift detection of a possible burst DATE: 08/03/15 02:46:19 GMT FROM: David Palmer at LANL K. L. Page (U Leicester), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), M. Stamatikos (NASA/ORAU), E. Troja (U Leicester/INAF-IASFPA) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team: At 02:25:01 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080315 (trigger=306323). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 155.182, +41.729 which is RA(J2000) = 10h 20m 44s Dec(J2000) = +41d 43' 44" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for a 64-second image trigger, the TDRSS light curve shows no obvious variation. Further BAT analysis will rely on the Malindi-downlinked data. The XRT began observing the field at 02:27:07.3 UT, 125.9 seconds after the BAT trigger. No source was detected in the promptly available XRT data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 400 seconds with the V filter starting 125 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 18.5 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected extinction of about 0.04 magnitudes. Burst Advocate for this burst is K. L. Page (kpa AT star.le.ac.uk). 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: 7417 SUBJECT: GRB 080315: TAROT Calern observatory optical observations DATE: 08/03/15 03:08:37 GMT FROM: Alain Klotz at CESR-CNRS Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report: We imaged the field of GRB 080315 detected by SWIFT (trigger 306323) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 85.0s after the GRB trigger (9.4s after the notice). The elevation of the field decreased from from 45 degrees above horizon and weather conditions were excellents. The date of trigger : t0 = 2008-03-15T02:25:01.3 The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT with a limiting magnitude of: t0+85.0s to t0+145.0s : R > 16.8 The second image is 30.0s exposure in tracking mode: t0+152.1s to t0+182.1s : R > 18.3 We co-added a series of exposures: t0+152.1s to t0+436.0s : R > 19.7 These images are unfiltered. Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon=177.6257 lat=+56.0163 and the galactic extinction in R band less than 0.1 magnitude estimated from D. Schlegel et al. 1998ApJ...500..525S. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7418 SUBJECT: GRB 080315: Optical observations DATE: 08/03/15 05:28:20 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (ESO, Chile), Virginie Chantry (U. Liege, Belgium), A.J. Castro-Tirado, M. Jelinek, J. Gorosabel (IAA-CSIC, Spain), C. Melo, A. Smette (ESO, Chile) report: We have observed the field of GRB 080315 (Page et al., GCN 7416) with the 1.3m Mercator telescope at La Palma starting at 02:55 UT (30 min after the burst). The observation consisted on a series of 24x60s I-band exposures. The combined exposure, with mean time 3:26 UT (61.3 minutes after the burst), does not show any new source inside the 3 arcmin BAT error box down to a limiting magnitude of I~20.8 (USNO-B1.0 was used as photometric reference) as compared to SDSS i-band frame. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7421 SUBJECT: Swift/UVOT observations of GRB 080315 DATE: 08/03/15 21:36:41 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (MSSL/UCL) and K. L. Page (U Leicester) report on behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 080315 starting 125 s after the BAT trigger (Page et al., GCN 7416). We do not find any source in any of the individual or co-added exposures, either within the BAT error circle or at the location of the weak source detected by XRT (Barthelmy et al. GCN 7420). The 5-sigma upper limits for detecting a source at the position of the XRT candidate in the co-added images are: Filter T_start T_stop Exp Mag (s) (s) (s) (5-sigma upper limit) ----------------------------------------------------- v 127 42160 6078.4 > 20.79 b 608 40422 5815.6 > 21.84 u 582 7467 620.7 > 20.30 uvw1 558 7281 468.7 > 19.82 uvm2 533 7075 858.7 > 20.00 uvw2 113 41328 5847.3 > 21.63 ----------------------------------------------------- The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E(B-V) = 0.01 mag. All photometry is on the UVOT light flight system described in Poole et al. (2008, MNRAS, 383, 627). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7422 SUBJECT: GRB080315: Bok Optical Observations DATE: 08/03/16 05:24:26 GMT FROM: Peter A. Milne at Super-LOTIS P.A.Milne (Steward Obs) and A. Updike report on behalf of the Super-LOTIS GRB team: We observed the field of GRB 080315 starting at UT=02:43:58 (~19min since GRB) with the 2.3m Bok telescope at Kitt Peak, AZ. We obtained 23 x 60-sec and 7 x 120-sec images in the R-band filter. We do not detect emission at the location of the faint XRT source (Palmer et al., GCN 7416) to a limiting magnitude of R~23.5. We do not detect any sources other than ones apparent in the DSS, to the limit of the DSS image. We do not detect a fading/rising source between the initial 10 and final 10 images. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7638 SUBJECT: Possible GRB 080315: XRT non-detection of afterglow DATE: 08/04/22 13:28:33 GMT FROM: Kim Page at U.of Leicester K.L. Page (U. Leicester) and N. Gehrels (NASA/GSFC) report on behalf of the Swift-XRT team: Swift-XRT performed follow-up observations of the possible GRB 080315 (BAT trigger number 306323) about a month after the trigger, in order to determine whether or not the possible X-ray afterglow mentioned in GCN Circ. 7420 had faded. We find that this source is at a count rate consistent with that of our original observation, so conclude that it is not the afterglow. Thus, no afterglow was detected for this trigger. Excluding this constant X-ray source, the 3-sigma upper limit within the BAT error circle from the observation directly following the trigger (25 ks on 2008-03-15) was 5.9 x 10^-4 count s^-1; the late-time data (30 ks between 2008-04-16 and 2008-04-21) provide a limit of 5.2 x 10^-4 count s^-1. We cannot rule out that this was a real burst, but given the lack of XRT detection and marginal BAT detection it is not likely.