This file contains the "A" and the "B" burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8180 SUBJECT: GRB 080905: Swift detection of a probably-short burst DATE: 08/09/05 12:19:45 GMT FROM: Claudio Pagani at PSU/Swift-XRT C. Pagani (PSU), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), D. Grupe (PSU), S. T. Holland (CRESST/USRA/GSFC), H. A. Krimm (CRESST/GSFC/USRA), J. Mao (INAF-OAB), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Preger (ASDC), J. L. Racusin (PSU), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-IASFPA), P. Schady (MSSL-UCL), M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester), M. C. Stroh (PSU), E. Troja (INAF-IASFPA), T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the Swift Team: At 11:58:54 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080905 (trigger=323870). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 287.662, -18.877 which is RA(J2000) = 19h 10m 39s Dec(J2000) = -18d 52' 37" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows 3 peaks with a total duration of about 2 sec. The spectrum is hard, with most response above 25 keV in the BAT energy range. The peak count rate was ~4500 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 12:01:05.3 UT, 130.4 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 287.67363, -18.87986 which is equivalent to: RA(J2000) = 19h 10m 41.67s Dec(J2000) = -18d 52' 47.5" with an uncertainty of 2.8 arcseconds (radius, 90% containment). This location is 40 arcseconds from the BAT onboard position, within the BAT error circle. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 8.95e+20 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 114 seconds after the BAT trigger. No 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 3-sigma upper limit at the location of the XRT position is 17.8 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.14. Burst Advocate for this burst is C. Pagani (pagani AT astro.psu.edu). 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: 8181 SUBJECT: GRB 080905: R & I-band optical observations DATE: 08/09/05 16:47:34 GMT FROM: Javier Gorosabel at IAA-CSIC P. Tristram (MOA, Univ. of Canterbury), A.J. Castro-Tirado (IAA-CSIC, Granada), P. Yock (Univ. of Auckland), J. Gorosabel (IAA-CSIC, Granada), A. de Ugarte Postigo (ESO, Santiago), report on behalf of a larger collaboration: "Following the detection by Swift of GRB 080905 (Pagani et al. GCNC 8180), we have obtained R & I-band images at the 0.6m telescope of the Mt. John Observatory, New Zealand. The images were taken starting on Sep 5.529 UT (i.e. 43 min post-burst). We do not detect any object brighter than R=20.8 and I=20.3 consistent with the XRT position. We note the presence of two extended R~15 (R~15.4) objects 8.5" (10") South (North-East) (Object A at RA(J2000)=19:10:41.51, DEC(J2000)=-18:52:56.2 and Object B at RA(J2000)=19:10:41.10, DEC(J2000)=-18:52:40.6, respectively) from the XRT position which could be hosting the probably-short GRB 080905. A finding chart can be found at http://www.sc.eso.org/~adeugart/GRB/080905/080905fc.jpg" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8182 SUBJECT: GRB 080905B: Swift detection of a burst with possible optical counterpart DATE: 08/09/05 17:22:03 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT M. C. Stroh (PSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC), S. Immler (CRESST/GSFC/UMD), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester), C. Pagani (PSU), K. L. Page (U Leicester), B. Preger (ASDC), J. L. Racusin (PSU), T. Sakamoto (NASA/UMBC), P. Schady (MSSL-UCL), R. L. C. Starling (U Leicester) and L. Vetere (PSU) report on behalf of the Swift Team: At 16:55:45 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080905B (trigger=323898). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 301.723, -62.571 which is RA(J2000) = 20h 06m 53s Dec(J2000) = -62d 34' 15" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed three well separated peaks each about 10 seconds long with a total burst duration of about 90 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~4 sec after the trigger. The XRT began observing the field at 16:57:28.6 UT, 103.2 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source with an enhanced position: RA, Dec 301.74027, -62.56347 which is equivalent to: RA(J2000) = 20h 06m 57.66s Dec(J2000) = -62d 33' 48.5" with an uncertainty of 2.7 arcseconds (radius, 90% containment). This location is 39 arcseconds from the BAT onboard position, within the BAT error circle. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (3.49e+20 cm^-2, Kalberla et al. 2005), with an excess column of 1.7 (+1.47/-1.31) x 10^21 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 2.11e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 112 seconds after the BAT trigger. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. Inside the XRT error circle is a 16th mag source that is starlike in the DSS, but appears extended or double in the UVOT image and may be an optical afterglow. A second finding chart in V does not allow us to confirm or reject the candidate at this time. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05. Burst Advocate for this burst is M. C. Stroh (stroh AT astroh.org). 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: 8185 SUBJECT: GRB 080905A: Swift-XRT Refined Analysis DATE: 08/09/06 02:31:56 GMT FROM: Claudio Pagani at PSU/Swift-XRT C. Pagani and J. Racusin (PSU) report on behalf of the Swift-XRT team: We have analyzed the first orbit of Swift-XRT data for the short GRB 080905A (Pagani et al., GCN 8180) beginning at T0+130 seconds to T0+1.1 ks. The enhanced XRT position given in GCN Circ 8180 is 40 arcseconds from the BAT onboard position, within the BAT error circle. The XRT lightcurve shows an initial count rate of approximately 6 counts/s for the first 100 seconds of observations, followed by a steep decay and a shallower phase. The decaying lightcurve can be fit with a broken power-law with an initial decay index of 6.4+/-2.0, a break at approximately T0+400 seconds and a later decay index of 1.0+/-0.5. The spectrum of 1 ks of Photon counting mode data from the first orbit can be fit by an absorbed power-law with a photon index of 1.3+/-0.3 and absorption consistent with the Galactic value along the line of sight (9e20 cm^-2, Kalberla et al. 2005). The average observed (unabsorbed) flux of the PC mode data is 2.9e-9 (3.1e-10) ergs cm^-2 s^-1. Assuming the X-ray emission continues to decline at the same rate, we predict a 0.3-10.0 keV XRT count rate of 0.001 counts/s at T+24hr, which corresponds to an observed flux of 7e-14 ergs cm^-2 s^-1. This Circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8187 SUBJECT: GRB 080905A, Swift-BAT refined analysis DATE: 08/09/06 16:51:33 GMT FROM: Scott Barthelmy at NASA/GSFC J. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), C. Pagani (PSU), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 080905A (trigger #323870) (Pagani, et al., GCN Circ. 8180). The BAT ground-calculated position is RA, Dec = 287.663, -18.865 deg, which is RA(J2000) = 19h 10m 39.1s Dec(J2000) = -18d 51' 55.4" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 56%. The mask-weighted light curve shows three peaks; the first two are partially overlapping, starting at T+0.0 and ending at ~T+0.4 sec. The third peak starts at ~T+0.6 and ends at ~T+1.3 sec. T90 (15-350 keV) is 1.0 +- 0.1 sec (estimated error including systematics). The time-averaged spectrum from T+0.0 to T+1.1 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.85 +- 0.24. The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.04 sec in the 15-150 keV band is 1.3 +- 0.2 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/323870/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8188 SUBJECT: GRB 080905B, Swift-BAT refined analysis DATE: 08/09/06 17:03:34 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), M. C. Stroh (PSU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+903 sec from recent telemetry downlinks, we report further analysis of BAT GRB 080905B (trigger #323898) (Stroh, et al., GCN Circ. 8182). The BAT ground-calculated position is RA, Dec = 301.746, -62.568 deg, which is RA(J2000) = 20h 06m 59.1s Dec(J2000) = -62d 34' 03.8" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 37%. The mask-weighted light curve shows two clusters pf peaks. The first starts at ~T-2 sec and almost returns to background levels as the second cluster starts around T+40 sec. The second cluster returns to background at ~T+220 sec. T90 (15-350 keV) is 128 +- 16 sec (estimated error including systematics). The time-averaged spectrum from T-15.5 to T+128.5 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.78 +- 0.15. The fluence in the 15-150 keV band is 1.8 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+8.02 sec in the 15-150 keV band is 0.5 +- 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/323898/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8189 SUBJECT: GRB 080905B: Enhanced Swift-XRT position DATE: 08/09/06 17:20:42 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 979 s of XRT Photon Counting mode data and 1 UVOT images for GRB 080905B, 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 = 301.74122, -62.56313 which is equivalent to: RA (J2000): 20h 06m 57.89s Dec (J2000): -62d 33' 47.3" with an uncertainty of 1.7 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 http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an extension of this method. This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8190 SUBJECT: GRB 080905A: NOT and VLT observations DATE: 08/09/06 18:40:26 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani (DARK/NBI), A. de Ugarte Postigo (ESO), J. P. U. Fynbo (DARK/NBI), A. J. Levan (Univ. Warwick), E. Rol (Univ. Leicester), N. R. Tanvir (Univ. Leicester), C. C. Thoene (DARK/NBI), J. Telting (NOT), A. Baran (Cracow Univ.), report on behalf of a larger collaboration: We observed the field of the short GRB 080905A (Pagani et al., GCN 8180) with the NOT and the VLT telescopes equipped with ALFOSC and FORS2, respectively. The NOT observations started on 2008 Sep 5.854 UT (8.51 hr after the GRB) and the total exposure time was 30 min. The VLT observations started on 2008 Sep 6.097 UT (14.3 hr after the GRB) and the total exposure was 40 min. All images were taken with the R filter. Inside the XRT error circle, we detect a single, faint source with R ~ 24 (against USNO-B1 stars), visible in both the NOT and VLT images. No variability of the source can be robustly determined, hence we cannot assess the relationship of this object with the GRB, especially given the relatively crowded field (Galactic latitude -12.6). Further observations are planned. The coordinates of this object are: RA(J2000) = 19:10:41.73 Dec(J2000) = -18:52:47.3 with an error of ~0.6". We note that in our NOT images (seeing ~1"), the extended objects identified by Tristram et al. (GCN 8181) appear resolved into several pointlike sources. Finding charts can be found at the following URL: http://www.astro.ku.dk/~malesani/GRB/080905A We acknowledge significant support from the observing staff at Paranal, in particular Swetlana Hubrig, Elena Mason and Andres Pino. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8191 SUBJECT: GRB 080905B: VLT redshift DATE: 08/09/07 00:16:14 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst Paul M. Vreeswijk, Johan P. U. Fynbo, Daniele Malesani, Jens Hjorth (DARK/NBI), Antonio de Ugarte Postigo (ESO), report on behalf of a larger collaboration: We observed the field of GRB 080905B (Stroh et al., GCN 8182) with the ESO VLT equipped with FORS2. Several spectra were obtained with different grism choices, beginning on 2008 Sep 6.053 UT (8.34 hr after the GRB), and covering the wavelength ranges 3800-9500 AA at low to moderate resolution. In the acquisition images, we clearly detect a point source inside the refined XRT error circle (Osborne et al., GCN 8189), at the coordinates (J2000): RA = 20:06:57.90 Dec = -62:33:46.8 This position is consistent with that of the UVOT candidate afterglow reported by Stroh et al. (GCN 8182), the object being now significantly fainter (R ~ 20.2). We note that this position is 3.8" off the center of the bright 2MASS galaxy 2MASX J20065732-6233465, also visible in the DSS and in the UVOT images. Spectroscopy of the afterglow reveals resonance absorption features from several ions, including OI, SiII, CIV, FeII, AlII, AlIII, MgII, MgI, at a redshift z = 2.374. The detection of transitions from fine-structure levels of FeII indicates that this is the redshift of the GRB, under the assumption that these levels are populated by GRB afterglow ultraviolet photons. We also find evidence for an intervening absorber at z = 1.438. We acknowledge excellent support from the Paranal staff, in particular Elena Mason and Andres Pino. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8192 SUBJECT: GRB 080905B: Refined UVOT Analysis DATE: 08/09/07 00:43:31 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) & M. C. Stroh (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT observed the field of GRB 080905B starting 94 s after the BAT trigger (Stroh et al., 2008, GCNC. 8182). Settled observations started at T + 113 s. We detect the optical afterglow (Stroh et al., GCNC 8182) in the v and white filters at the UVOT-enhanced location of the XRT afterglow (Osborne, et al., 2008, GCNC 8089). There is an uncertain detection in the b filter. The refined UVOT source position is RA (J2000.0) = 20:06:57.89 Dec (J2000.0) = -62:33:47.0 with an estimated uncertainty of 0.7 arcsec (radius, 90% confidence). We note that the afterglow is slightly blended with the USNO-B1.0 star 274-094527, which makes it dificult to confirm the detection in the b band. Magnitudes and upper limits are reported below. Filter TSTART TSTOP Exposure Mag Err Comment white 113 213 98 18.70 0.09 v 219 619 394 16.60 0.07 b 699 6033 206 19.49 0.15 uncertain detection u 674 5828 216 >20.7 3-sigma upper limit uvw1 650 5623 197 >20.3 3-sigma upper limit uvm2 5218 5418 197 >19.9 3-sigma upper limit uvw2 729 6445 197 >20.5 3-sigma upper limit The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E_{B-V} = 0.05 mag (Schlegel et al., 1998, ApJS, 500, 525). The photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383,627). The possible detection in the b filter, coupled with the non-detections in the u, uvw1, uvm2, and uvw2 filters, are consistent with a redshift of approximately z < 3.3. The power-law decay index in the v band between 763 and 6505 s is -0.88. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8193 SUBJECT: GRB 080905B: Swift-XRT Refined Analysis DATE: 08/09/07 07:06:17 GMT FROM: Michael Stroh at PSU/Swift M.C. Stroh (PSU) reports on behalf of the Swift-XRT team: We have analyzed the Swift-XRT data obtained for GRB 080905B (Stroh et al., GCN Circ. 8182), totaling 85s of Windowed Timing and 10.2ks of Photon Counting data. The 0.3-10 keV X-ray light-curve can be fit by a double broken power- law with an initial decay index of 2.46 +/- 0.18, second decay index of 0.01 +/- 0.18, and a third decay index of 1.41 +/- 0.4 with first and second break points at 258s and 2734s respectively. We predict counting rates of 7.88e-3 cts/s and 4.44e-3 cts/s at T+48 and T+72 hours. The spectrum from the Windowed Timing data can be fit with a power-law in excess of the Galactic value (3.5e20 cm-2, Kalberla et al. 2005), with an intrinsic column density of 1.32 (+0.57/-0.48)e22 cm^-2 and a photon index of 1.49 (+0.13/-0.12). The observed (unabsorbed) 0.3-10 keV flux is 5.34e-10 (6.1e-10) ergs/cm^2/s. The spectrum from the Photon Counting data can be fit with a power law with intrinsic column density of 2.26 (+0.53/-0.47)e22 cm^-2 and a photon index of 1.92 (+0.10/-0.10). The observed (unabsorbed) 0.3-10 keV flux is 1.259e-10 (1.7e-10) ergs/cm^2/s. This is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8195 SUBJECT: GRB 080905A: optical afterglow DATE: 08/09/07 10:35:30 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst A. de Ugarte Postigo (ESO), D. Malesani (DARK/NBI), A. J. Levan (Univ. Warwick), J. Hjorth (DARK/NBI), N. R. Tanvir (Univ. Leicester), report on behalf of a larger collaboration: We observed again the field of the short GRB 080905A (Pagani et al., GCN 8180) with the ESO VLT equipped with FORS2. R-band observations were carried out starting on 2008 Sep 7.004 UT (1.50 days after the GRB) and the total exposure time was 40 minutes. The object located inside the XRT error circle visible in our early VLT images (Malesani et al., GCN 8190) has clearly faded between the two observations, and is thus likely the optical afterglow of GRB 080905A. We note that this object is located outside the revised 2.2"-radius (90%) UVOT-enhanced XRT error circle (distance from center 4.6"), as provided at http://www.swift.ac.uk/xrt_positions/index.php (value of Sep 7.4 UT). In our second epoch image, which is deeper and has a better seeing (~0.9"), we also note the presence of a bright extended object, possibly a spiral galaxy, about 9" S, 3" E of the afterglow (partially covered by foreground stars). Finding charts can be found at http://www.astro.ku.dk/~malesani/GRB/080905A/#epoch2 We acknowledge significant support from the ESO observing staff at Paranal, in particular Elena Mason, Andres Pino and Swetlana Hubrig. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8202 SUBJECT: GRB 080905A: MITSuME Akeno optical upper limits DATE: 08/09/08 13:33:19 GMT FROM: Nobuyuki Kawai at Tokyo Tech H. Nakajima, T. Shimokawabe, Y.A. Mori, Y. Kudou, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We performed optical imaging observation of the field of GRB 080905A (C. Pagani et al. GCN 8180) with the 3-color 50cm MITSuME Telescope at Akeno, Japan from 12:40:12 UT (42min after the trigger) to 14:32:07 UT. In the co-added images of Ic, Rc, and g' bands, we did not detect any afterglow candidate in the XRT error circle. The 3-sigma limiting magnitudes based on USNO-B1.0 (I-band) and NOMAD (R-band,g'-band) stars are following: Filter Start(UT) End(UT) Exposure LimitMag --------------------------------------------------- g' 12:40:12 13:14:31 30 x 60 s 17.1 Rc 12:40:12 13:14:31 30 x 60 s 17.6 Ic 12:40:12 13:14:31 30 x 60 s 17.6 --------------------------------------------------- //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8203 SUBJECT: GRB 080905A: Enhanced Swift-XRT position DATE: 08/09/08 15:06:05 GMT FROM: Phil Evans at U of Leicester P.A. Evans, J.P. Osborne and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team: Using more data than were available at the time of de Ugarte Postigo et al. (GCN Circ 8195), the UVOT-enhanced X-ray position of GRB 080905A has been improved to RA, Dec = 287.67390, -18.88022 which is equivalent to: RA (J2000): 19 10 41.74 Dec (J2000): -18 52 48.8 with an uncertainty of 1.6 arcsec (90% confidence). This position lies 1.5" from the optical counterpart identified by Malesani et al (GCN Circ. 8190), consistent with that position. Position enhancement, using the XRT-UVOT alignment and matching to the USNO-B1 catalogue, is described by Goad et al. (2007, A&A, 476, 1401 http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an extension of this method. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8204 SUBJECT: GRB 080905A: Fermi Gamma-ray Burst Monitor detection DATE: 08/09/09 12:03:02 GMT FROM: Elisabetta Bissaldi at MPE E. Bissaldi, S. McBreen (MPE), V. Connaughton (UAH) and A. von Kienlin (MPE) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 11:58:55 UT on 5 September 2008, the Fermi GBM triggered and located GRB 080905A (trigger 242308736 / 080905499), which was also detected by Swift (Pagani et al., GCN 8180). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 286.3, Dec = -18.2 (J2000 degrees) (equivalent to J2000 19h 05m, -18d 12'), with a statistical uncertainty of 4.6 degree (radius, 1-sigma containment; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This position is 1.5 deg from the Swift refined position (Evans et al., GCN 8203). The angle from the Fermi LAT boresight to the Swift position is 28 degrees. This short GRB consists of two peaks, the first from T0 to T0+0.4 sec and the second from T0+0.6 sec to T0+1.1 sec. The first peak shows substructure in agreement with the Swift-BAT refined analysis (J. Cummings et al., GCN 8187). T90 (50-300 keV) is about 1 sec. The time-averaged spectrum from T0 to T0+1 sec is well fit by a power law function with index -0.96 +/- 0.05. The fluence (50-300 keV) is 2.8(+/-0.2)E-07 erg/cm2 and the peak flux (50-300 keV) is 6.1 +/- 0.8 ph/cm2/s. The spectral analysis results presented above are preliminary; final results will be published in the Fermi GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8205 SUBJECT: GRB 080905B: Fermi Gamma-ray Burst Monitor detection DATE: 08/09/09 18:15:32 GMT FROM: Narayana Bhat at U Alabama/Huntsville/GBM P. N. Bhat (UAH), W. Paciesas (UAH) and A.J. van der Horst (NASA/ORAU) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 16:55:46 UT on 5 September 2008, the Fermi GBM triggered and located GRB 080905B (trigger 242326547 / 080905705), which was also detected by Swift (Stroh et al., GCN 8182). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 307.1, Dec = -60.2 (J2000 degrees) (equivalent to J2000 20h 28m, -60d 12'), with a statistical uncertainty of 5.7 degree (radius, 1-sigma containment; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight to the GBM localization is 82 degrees. This long GRB consists of one main peak at trigger time, possibly a weak pre-trigger at T-20 s and second peak at T0 + 70 sec and the third from T0+80 sec to T0+110 sec similar to the Swift light curve. The burst duration (in the energy range 20-1000 keV) T90 is about 159 sec. The time-averaged spectrum from T0-20 to T0+110 sec is well fit by a power law function with index -1.75 +/- 0.12.The fluence (20-1000 keV) is 4.1(+/-0.3)E-08 erg/cm2and the peak flux (20-1000 keV) is 0.21 +/- 0.02 ph/cm2/s. The spectral analysis results presented above are preliminary; final results will be published in the Fermi GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8207 SUBJECT: GRB 080905B: Watcher optical detection DATE: 08/09/10 12:26:32 GMT FROM: John French at UCD,Ireland John French (UCD School of Physics, DARK/NBI), Gary Melady (UCD School of Physics), Daniele Malesani, Paul Vreeswijk (DARK/NBI) report on behalf of a larger collaboration: The Watcher 40 cm robotic telescope at Boyden Observatory, South Africa, began imaging the field of GRB 080905B (Stroh et al al. GCN 8182) at 16:56:28 UT, 43 s after the Swift triggger. In a stacked sequence of 10 unfiltered 10 s exposures, with a mid-time of 16:57:37 UT (112 s after the Swift trigger), we detect a point source inside the refined XRT error circle (Osborne et al. GCN 8189), at a position consistent with the detections reported by Holland et al. (GCN 8192) , Vreeswijk et al. (GCN 8191) and Stroh et al. (GCN 8182). We measure a magnitude of 16.2 +/- 0.2 for the source, based on comparison with the USNO-B1 star at RA 20:06:51.361, Dec -62:32:52.55. Further analysis is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8208 SUBJECT: GRB080905A: Swift/UVOT Upper Limits DATE: 08/09/10 13:18:20 GMT FROM: Peter Brown at PSU P. J. Brown and C. Pagani (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT observed the field of GRB 080905A starting about 114 s after the BAT detection (Pagani et al., GCN Circ. 8180). We do not detect any source in the revised XRT error circle (Evans et al., GCN Circ. 8203) including the faint optical afterglow seen by Malesani et al. (GCN Circ. 8190) in any of the UVOT filters down to the following 3 sigma upper limits (where T_start and T_stop represent the elapsed time since the BAT trigger in seconds). Filter T_start(s) T_stop Exp(s) MagLimit white 114 970 198 >21.3 uvw2 730 750 19 >18.1 uvm2 626 4520 95 >19.2 uvw1 651 825 39 >18.8 u 675 850 39 >19.2 b 700 865 15 >18.9 v 220 1250 1014 >20.6 The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E(B-V) = 0.14 mag (Schlegel et al., 1998, ApJS, 500, 525). The photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383,627). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8213 SUBJECT: GRB 080905C: Fermi GBM detection DATE: 08/09/11 15:08:30 GMT FROM: Elisabetta Bissaldi at MPE E. Bissaldi, S. McBreen and A. von Kienlin (MPE) report on behalf of the Fermi GBM Team: "At 13:41:29 UT on 5 September 2008, the Fermi Gamma-ray Burst Monitor triggered and located GRB 080905C (trigger 242314890 / 080905570). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 96.9, Dec = -69.8 (J2000 degrees) (equivalent to J2000 06h 28m, -69d 48'), with a statistical uncertainty of 8 degrees (radius, 1-sigma containment; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 108 degrees. This event comprises three pulses beginning at T0-4 s. The main emission occurs during the first 11 sec and T90 (50-300 keV) is about 28 s. The time-averaged spectrum from T0-3.6 s to T0+17 s is adequately fit by a power law function with an exponential high energy cutoff. The power law index is -0.90 +/-0.17 and the cutoff energy, parameterized as Epeak, is 78.8 +/- 5.9 keV. The fluence (25-1000 keV) is 4.6 (+/-0.3)E-06 erg/cm2 and the peak flux (25-1000 keV) on the 128 ms timescale is 4.4 +/- 1.9 ph/cm2/s. The spectral analysis results presented above are preliminary; the final results will be published in the Fermi GBM GRB Catalog."