//////////////////////////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12083 SUBJECT: Swift J185003.2-005627: Swift detection of a burst from a new Galactic transient DATE: 11/06/25 00:32:47 GMT FROM: David Palmer at LANL A. P. Beardmore (U Leicester), W. H. Baumgartner (GSFC/UMBC), J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), C. Pagani (U Leicester), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), C. J. Saxton (UCL-MSSL), M. H. Siegel (PSU) and C. A. Swenson (PSU) report on behalf of the Swift Team: At 00:06:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located an unknown source (trigger=456014). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 282.551, -0.968 which is RA(J2000) = 18h 50m 12s Dec(J2000) = -00d 58' 04" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 2 sec. The peak count rate was ~400 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 00:07:42.4 UT, 94.8 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 282.5134, -0.9410 which is equivalent to: RA(J2000) = 18h 50m 03.21s Dec(J2000) = -00d 56' 27.5" with an uncertainty of 5.4 arcseconds (radius, 90% containment). This location is 166 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 250 seconds with the U filter starting 263 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. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. Data from the list of sources generated on-board are not available at this time. Given the soft nature of the initial BAT detection and the proximity to the Galactic plane (7 arcmin) we believe that this is probably a previously-unknown Galactic transient, rather than a cosmological GRB, which we name 'Swift J185003.2-005627'. Burst Advocate for this burst is A. P. Beardmore (apb 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: 12084 SUBJECT: Swift J185003.2-005627: TAROT Calern observatory optical observations DATE: 11/06/25 00:52:03 GMT FROM: Alain Klotz at CESR-CNRS Klotz A. (CESR-OMP), Gendre B. (ASDC), Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report: We imaged the field of Swift J185003.2-005627 detected by SWIFT (trigger 456014, Beardmore et al. 2011 GCNC 12083) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 133.0s after the GRB trigger. The elevation of the field increased from 45 degrees above horizon and weather conditions were very good. Galactic coordinates are lon= 31.9297 lat= -0.1669 that leads to a very high galactic extinction in R band. The date of trigger : t0 = 2011-06-25T00:06:07 The first image is 30.0s exposure in tracking mode. No new source is detected in the XRT error box: t0+133.0s to t0+163.0s : R > 16.8 Until 1200 seconds after the trigger, no new source is detected in subsequent images. The field of view was also observed from TAROT La Silla (Chile) but the elevation is low (11 deg) and limiting magnitudes are not better. //////////////////////////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12085 SUBJECT: Swift J185003.2-005627: TAROT La Silla observatory optical observations DATE: 11/06/25 01:21:30 GMT FROM: Alain Klotz at CESR-CNRS Klotz A. (CESR-OMP), Gendre B. (ASDC), Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report: We imaged the field of Swift J185003.2-005627 detected by SWIFT (trigger 456014, Beardmore et al. 2011 GCNC 12083) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 53.6s after the GRB trigger (10.2s after the notice), i.e 80s before the first optical observation reported from TAROT Calern (see Klotz et al. 2011 GCNC 12084). The elevation of the field increased from 10 degrees above horizon and weather conditions were good. 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+53.6s to t0+113.6s : R > 15.4 //////////////////////////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12086 SUBJECT: Swift J185003.2-005627: Swift-BAT refined analysis DATE: 11/06/25 12:34:42 GMT FROM: Scott Barthelmy at NASA/GSFC C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+302 sec from recent telemetry downlinks, we report further analysis of Swift J185003.2-005627 (trigger #456014) (Beardmore, et al., GCN Circ. 12083). The BAT ground-calculated position is RA, Dec = 282.509, -0.946 deg which is RA(J2000) = 18h 50m 02.2s Dec(J2000) = -00d 56' 47.3" with an uncertainty of 3.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 41%. The mask-weighted light curve shows a single pulse starting at ~T-2 sec, peaking at ~T+4 sec, and ending at ~T+14 sec, entirely in the lowest energy band (15-25 keV). T90 (15-350 keV) is 12.0 +- 4.5 sec (estimated error including systematics). The time-averaged spectrum from T-1.7 to T+13.3 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 5.11 +- 0.98. The fluence in the 15-150 keV band is 1.6 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.28 sec in the 15-150 keV band is 0.6 +- 0.3 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/456014/BA/ //////////////////////////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12087 SUBJECT: Swift J185003.2-005627: Swift-XRT/UVOT refined analysis DATE: 11/06/25 16:51:02 GMT FROM: Andy Beardmore at U Leicester A. P. Beardmore (U. Leicester), S. Campana (INAF-OAB), J. A. Kennea (PSU) and C. A. Swenson (PSU) report on behalf of the Swift/XRT and UVOT teams: We have analysed 2.8 ks of Swift/XRT data from the transient Swift J185003.2-005627 (Beardmore, et al., GCN Circ. 12083), from 88 s to 17.5 ks after the BAT trigger. The data comprise 421 s in Windowed Timing (WT) mode (the first 5 s were taken while Swift was slewing), with the remainder in Photon Counting (PC) mode. The astrometrically corrected X-ray position for this source (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue), derived from 1660 s of XRT Photon Counting mode data and 2 UVOT images, is RA, Dec = 282.51390, -0.93980 which is equivalent to: RA (J2000): 18 50 3.33 Dec (J2000): -00 56 23.3 with an uncertainty of 1.7 arcsec (radius, 90% confidence). This position may be improved as more data are received. The position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). The X-ray light curve initially decays like a powerlaw, with an index of 1.158 (+0.102, -0.125), before flattening to a slope of 0.161 (+0.035, -0.072) at T +365 (+109, -40) s after the trigger. A spectrum formed from the WT mode data from T+101 to T+429 s after the trigger is best fit by an absorbed blackbody, with a temperature of 0.83 +/- 0.03 keV and column density of 1.71 +/- 0.19 x 10^22 cm^-2, consistent with the Galactic column in the direction of the source (Kalberla et al. 2005). The observed (unabsorbed) 0.3-10 keV flux for this spectrum is 4.85e-10 (6.76e-10) ergs cm^-2 s^-1. The XRT spectrum, together with the soft BAT spectrum reported by Markwardt et al. (GCN Circ. 12086) and the location of the source in the Galactic plane, is suggestive of emission from a type I burst. Swift/UVOT observations of the field were also performed but no optical counterpart is detected at the XRT position. Preliminary 3-sigma upper limits, using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627), are: Filter T_start(s) T_stop(s) Exp(s) Mag --------------------------------------------------------------------------- white 104 5305 628 >18.9 v 593 1763 136 >17.2 b 519 1863 136 >18.9 u 263 1837 382 >19.9 w1 642 1813 130 >19.7 w2 742 5340 125 >20.3 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 16.09 in the direction of the transient (Schlegel et al. 1998). ////////////////////////////////////////////////////////////////////////////////////////////