//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7721 SUBJECT: GRB 080515: Swift detection of a burst DATE: 08/05/15 06:19:28 GMT FROM: David Palmer at LANL S. T. Holland (CRESST/USRA/GSFC), A. P. Beardmore (U Leicester), P. A. Evans (U Leicester), E. A. Hoversten (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (CRESST/GSFC/UMD), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL) and R. L. C. Starling (U Leicester) report on behalf of the Swift Team: At 06:01:13 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080515 (trigger=311658). Swift could not slew to the burst due to Sun constraint. The BAT on-board calculated location is RA, Dec 3.150, +32.599 which is RA(J2000) = 00h 12m 36s Dec(J2000) = +32d 35' 57" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve from TDRSS was truncated by the beginning of a Malindi downlink and is further complicated as we were coming out of the SAA at the time, but shows activity from the trigger time to the end of available data at T+8s, with a peak count rate of ~500 counts/s (15-350 keV). This burst is only 45.9 degrees from the Sun, so there will be no prompt XRT or UVOT data. The field will be outside the Swift Sun observing constraint tomorrow. Burst Advocate for this burst is S. T. Holland (sholland 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: 7726 SUBJECT: GRB 080515, Swift-BAT refined analysis DATE: 08/05/15 13:44:19 GMT FROM: Scott Barthelmy at NASA/GSFC E. Fenimore (LANL), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), J. Cummings (GSFC/UMBC), N. Gehrels (GSFC), S. T. Holland (CRESST/USRA/GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-237 to T+962 sec from recent telemetry downlinks, we report further analysis of BAT GRB 080515 (trigger #311658) (Holland, et al., GCN Circ. 7721). The BAT ground-calculated position is RA, Dec = 3.166, 32.564 deg, which is RA(J2000) = 00h 12m 39.8s Dec(J2000) = +32d 33' 49.9" with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 8%. The mask-weighted light curve shows a single peak starting at ~T-5 sec, peaking at ~T+2 sec, and ending at ~T+25 sec. T90 (15-350 keV) is 21 +- 5 sec (estimated error including systematics). The time-averaged spectrum from T-2.6 to T+24.0 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.94 +- 1.21, and Epeak of 25.0 +- 15.6 keV (chi squared 47.2 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 2.0 +- 0.3 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+1.37 sec in the 15-150 keV band is 3.9 +- 0.7 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.44 +- 0.19 (chi squared 53.8 for 57 d.o.f.). 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/311658/BA/ We also note that the fluence ratio in a simple power-law fit between the 25-50 keV band and the 50-100 keV band is 1.35. This fluence ratio is larger than 1.32 which can be achieved in the Band function of alpha=-1.0, beta=-2.5, and Epeak=30 keV. Thus, preliminary analysis shows that Epeak of the burst is very likely around or below 30 keV. Therefore the burst can be classified as an X-ray flash (e.g. Sakamoto et al. ApJ in press, arXiv:0801.4319). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7762 SUBJECT: GRB 080515: Swift-XRT position and analysis DATE: 08/05/22 13:58:50 GMT FROM: Kim Page at U.of Leicester K.L. Page, A.P. Beardmore (U. Leicester) and S.T. Holland (CRESST/USRA/GSFC) report on behalf of the Swift-XRT and UVOT teams: A follow-up observation of GRB 080515 was performed about 1.5 days after the initial trigger (Holland et al., GCN Circ. 7721), when the burst was no longer Sun-constrained. An X-ray source was identified within the BAT ground-calculated error circle (Fenimore et al., GCN Circ. 7726). A further observation, 3.5 days later, confirmed that the source is fading, with alpha = 1.0 +0.7/-0.5. We therefore believe this is the X-ray afterglow of the GRB. The position of this source is RA, Dec = 3.16343, 32.57894, which is equivalent to: RA(J2000) = 00 12 39.22 Dec(J2000) = +32 34 44.2 with an uncertainty of 3.8 arcsec (radius, 90% containment). This is 54 arcsec from the BAT position given by Fenimore et al. in GCN Circ. 7726. A spectrum of the source can be fitted with a power-law of Gamma = 1.95 +/- 0.34, absorbed by the Galactic column of 4.65x10^20 cm^-2. This spectrum, averaged over 1.5-6.6 days after the burst, has an observed (unabsorbed) flux of 2.28x10^-13 (2.59x10^-13) erg cm^-2 s^-1. The field was observed by UVOT with the v filter for 6262 s between ~1.5 and 2.4 days after the BAT trigger. The XRT error circle is located in the scattered light halo of the B = 11.4 star TYC 2264-1051-1, so it is not possible to constrain the presence of an afterglow in the UVOT data. This circular is an official product of the Swift-XRT and UVOT teams. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7766 SUBJECT: GRB 080515: NIR magnitude correction DATE: 08/05/23 08:39:04 GMT FROM: Adria C. Updike at Clemson U Adria C. Updike, Ginger Bryngelson, and Dieter H. Hartmann (Clemson University) report on behalf of the Clemson GRB Follow-Up Team: The J-band magnitude at 5.33 days should have read 19.6 +/- 0.1 mag. We apologize for the mistake.