//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11484 SUBJECT: GRB 101224A: Swift detection of a short burst DATE: 10/12/24 05:56:50 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (CRESST/GSFC/USRA), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), M. M. Chester (PSU), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC), V. Mangano (INAF-IASFPA), K. L. Page (U Leicester), J. L. Racusin (NASA/GSFC), A. Rowlinson (U Leicester), T. Sakamoto (NASA/UMBC) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 05:27:13 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 101224A (trigger=440955). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 285.926, +45.715 which is RA(J2000) = 19h 03m 42s Dec(J2000) = +45d 42' 55" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peak with a duration of about 0.5 sec and some possible later activity. The peak count rate was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 05:28:31.4 UT, 77.7 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 150 seconds with the White filter starting 83 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The overlap of the sub-image and the BAT error circle is uncertain. The overlap of the 8'x8' region for the list of sources generated on-board and the BAT error circle is uncertain. No correction has been made for extinction. This event is fairly near the galactic plane (galactic lon,lat = 76.11, +17.05 deg) so there is a possibility that it is a new galactic transient rather than a GRB. Further identification will await analysis of the full data set. We also note the presence of the galaxy pair MCG+08-34-033 6.5 arc minutes from the center of the BAT field of view. These galaxies are at a distance of z = 0.017832 ~75 Mpc Burst Advocate for this burst is H. A. Krimm (krimm 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: 11485 SUBJECT: GRB 101224A - UVOT-enhanced XRT position DATE: 10/12/24 07:57:45 GMT FROM: Kim Page at U.of Leicester K.L. Page, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team: Upon analysis of the first downlink of Swift-XRT data for GRB 101224A, a faint source was detected within the BAT error circle (Krimm et al., GCN Circ. 11484). With the current data, it cannot be confirmed whether this source is fading. Using 1245 s of XRT Photon Counting mode data and 1 UVOT image, 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 = 285.92460, 45.71350 which is equivalent to: RA (J2000): 19 03 41.91 Dec (J2000): +45 42 48.5 with an uncertainty of 3.2 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 is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11486 SUBJECT: GRB 101224A, Swift-BAT refined analysis DATE: 10/12/24 14:19:41 GMT FROM: Hans Krimm at NASA-GSFC C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), 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 (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 101224A (trigger #440955) (Krimm, et al., GCN Circ. 11484). The BAT ground-calculated position is RA, Dec = 285.939, 45.706 deg which is RA(J2000) = 19h 03m 45.4s Dec(J2000) = +45d 42' 22.3" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 53%. The light curve consists of a pair of overlapping peaks of total duration 0.2 sec, T90 (15-350 keV) is 0.2 +- 0.01 sec (estimated error including systematics). The time-averaged spectrum from T+0.0 to T+0.3 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index -0.93 +- 1.52, and Epeak of 95.7 +- 35.2 keV (chi squared 62.87 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 5.8 +- 1.1 x 10^-8 erg/cm2 and the 1-sec peak flux measured from T-0.34 sec in the 15-150 keV band is 0.7 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.05 +- 0.26 (chi squared 71.61 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The hardness ratio S(50-100 keV)/S(25-50 keV) is 1.94, which when plotted against burst duration places GRB 101224A among the short-hard bursts in the distribution. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/440955/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11487 SUBJECT: GRB101224A: MITSuME Okayama optical upper limits DATE: 10/12/24 15:02:57 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 the MITSuME collaboration: We observed the field of GRB 101024A (Krimm et al., GCN 11484) 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 2010-12-24 08:59:48 UT (~3.6 hours after the burst). We did not find any new point source within the UVOT-enhanced XRT error circle (Page et al., GCNC 11485) in all the three bands. Three sigma upper limits of the OT are listed below. We used GSC2.3 catalog for flux calibration. T0+[day] MID-UT T-EXP[sec] g' Rc Ic ------------------------------------------------------ 0.18147 09:47:32 4680.0 >19.9 >19.7 >18.9 ------------------------------------------------------ T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11488 SUBJECT: GRB 101224A: Swift-XRT refined Analysis DATE: 10/12/24 16:46:07 GMT FROM: Claudio Pagani at U of Leicester C. Pagani (U. Leicester) and H. A. Krimm (CRESST/GSFC/USRA) reports on behalf of the Swift-XRT team: We have analysed 7.6 ks of XRT data for GRB 101224A (Krimm et al. GCN Circ. 11484), from 86 s to 24.5 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. Using 1245 s of PC mode data and 1 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 285.92460, +45.71350 which is equivalent to: RA (J2000): 19h 03m 41.91s Dec(J2000): +45d 42' 48.5" with an uncertainty of 3.2 arcsec (radius, 90% confidence). The afterglow is detected during the first orbit with 12 background subtracted source counts in 1.3 ks of PC data, at a count rate of 1.0 x 10^-2 counts s^-1, while it's not detected in the following orbits (1 background subtracted source count in 6.3 ks of PC data), for a 3 sigma upper limit of 1.4 x 10^-3 counts s^-1 A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 3.1 (+/-1.4). The best-fitting absorption column is 1.1 (+3.5, -0.6) x 10^21 cm^-2, consistent with the Galactic value of 4.4 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.9 x 10^-11 (5.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.1 (+3.5, -0.6) x 10^21 cm^-2 Galactic foreground: 4.4 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 3.1 (+/-1.4) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00440955. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11489 SUBJECT: GRB 101224A: Fermi GBM observation DATE: 10/12/24 16:51:15 GMT FROM: Sheila McBreen at MPE Sheila McBreen reports on behalf of the Fermi GBM Team: "At 05:27:13.86 UT on 24 December 2010, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 101224A (trigger 314861235/101224227), which was also detected by the Swift/BAT (Krimm et al. 2010, GCN 11484). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 72 degrees. The GBM light curve consists of one pulse with a duration of about 0.2 s (50-300 keV). The time-averaged spectrum from T0-0.064 to T0+0.256 s is adequately fit by a power law function with an exponential high-energy cutoff. The power law index is -0.83 (+0.38/-0.30) and the cutoff energy, parameterized as Epeak, is 330 (+402/-150) keV (CSTAT 509 for 488 d.o.f.). The event fluence (10-1000 keV) in this time interval is (2.4 +/- 0.5)E-07 erg/cm^2. The 64 ms peak photon flux measured starting from T0-0.064 s in the 10-1000 keV band is 5.40 +/- 0.82 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11490 SUBJECT: GRB 101224A: Swift/UVOT Upper Limits DATE: 10/12/24 17:38:45 GMT FROM: Wayne Landsman at GSFC/SSAI W. Landsman (GSFC/Adnet) and H.A. Krimm (CRESST/NASA/USRA) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 101224A 83 s after the BAT trigger (Krimm et al., GCN Circ. 11484). No optical afterglow consistent with the XRT position (Pagani et al., GCN Circ. 11488) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 83 233 147 > 20.8 u_FC 296 546 246 > 19.6 white 83 7201 659 > 21.9 v 628 12647 1173 > 20.2 b 551 24555 1030 > 21.4 u 296 23977 1583 > 20.8 w1 677 30339 1644 > 20.8 m2 652 30016 2569 > 20.8 w2 601 11734 1179 > 20.7 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11491 SUBJECT: GRB 101224A: Pre-event imaging from DeepSky; Detection of a source in the XRT error circle DATE: 10/12/24 18:25:20 GMT FROM: Josh Bloom at UC Berkeley P. E. Nugent (LBNL/UC Berkeley) and J. S. Bloom (UC Berkeley) report: "We co-added 49 archival images from the DeepSky* project at Palomar Observatory covering the field of GRB 101224A (Krimm et al., GCN 11484). The images were obtained between 2005-2007 from the Palomar-Quest Consortium at the Oschin Schmidt telescope. The 3-sigma limiting magnitude of the stack is approximately R ~ 23.0 mag. In the combined image we detect a faint (R = 20.5 +/- 0.2 mag, preliminary photometry, relative to nearby USNO catalog stars), near the center of the current XRT error circle (Pagani et al. GCN 11488). We cannot definitely determine if source is extended or not. An image of the field may be found at: http://lyra.berkeley.edu/~jbloom/grb101224a.pdf The brightness of the source appears to be just consistent with the UVOT upper limits (Landsman et al. GCN 11490), especially given the relatively red response of DeepSky imaging versus that of the UVOT. This source may be the (bright) host galaxy or a quiescent counterpart (if indeed the source is indeed Galactic in origin). However, further observations are required to establish the connection of this source to the GRB." * http://supernova.lbl.gov/~nugent/deepsky.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11492 SUBJECT: GRB 101224A: NOT optical observation DATE: 10/12/24 22:57:24 GMT FROM: Dong Xu at Weizmann Inst D. Xu (Weizmann Inst.), Ilya Ilyin (AIP), J.P.U. Fynbo (DARK/NBI) report on a larger collaboration: We observed the field of GRB 101224A (Krimm et al., GCN 11484; Pagani & Krimm, GCN 11488) at the Nordic Optical Telescope (NOT) equipped with StanCam. We obtained 5x300 s R-band images with a median time 20:53:06.8 UT (i.e., 15.4316 hr after the BAT trigger). The lowest airmass for these five images is 4.0 because the altitude was already ~13 degrees when observations started. The object shown in the pre-event image (Nugent & Bloom, GCN 11491) is clearly detected in our stacked image at the same position. The object is extended along the North-South axis to a considerable extent. We found R~21.5 mag against nearby two USNO B1 stars. This magnitude is a bit larger than the measurement from the pre-event image, and we caution that our images were obtained at high airmass and bias and flatfield frames are not available yet. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11596 SUBJECT: GRB 101224A, the review of the sky area in plate archives DATE: 11/01/23 15:59:09 GMT FROM: Valentyna Golovnya at Main Astro Obs,Kyiv GRB 101224A, the review of the sky area in plate archives V.V. Golovnya, L.M. Kizyun, L.K. Pakuliak (Main Astro Obs, Kyiv) report: We have undertaken the review of the sky area of GRB 101224A (K.L.Page et al., GCN 11485) on astronegatives, collected in Ukrainian NAS Main astronomical observatory plate archive (1976-1996). All the plates with the possible object appearance are digitized using Microtek ScanMaker 9800XL TMA flatbed scanner and the images have been placed into Golosiiv Plate Archive database DBGPA with open access to them. The list of plates is given in the table: YYYYMMDD UT Plates Exp. LimMag 19770622 22:14:06 GUA040C000430A 22.5 15.50 19840720 21:19:40 GUA040C000535A 60.0 17.60 19860716 21:18:54 GUA040C000961 16.0 17.60 19870701 22:16:16 GUA040C001064 16.0 17.60 19870822 19:11:46 GUA040C0001078A 16.0 15.65 No any object has been found in the point with the mentioned coordinates of GRB. But the double image of some object has been found at the distance near 6 arcsec from the probable GRB position on the two of selected plates. Brighness of the object is estimated as V = 17.2: Plates Obj RA(J2000) Dec(J2000) Mag GUA040C000535A Obj1 19:03:41.30 +45:42:47.2 17.2 Obj2 19:03:41.69 +45:42:40.5 17.0 GUA040C001064 Obj1 19:03:41.64 +45:42:41.5 17.3 Obj2 19:03:42.14 +45:42:36.4 17.4 Plates: –the plates archive identifier of DWA D/F=400/2000, M=103"/mm). GUA040C of the Ukrainian NAS Main Astro obs in Kyiv (Marsden's number - 83) the plate number [1]. Exp. - Duration of the maximum exposures (minutes). LimMag - Limited V mag, derived in the 15 minutes area around the location given in K.L.Page et al., GCN 11485: RA (J2000): 19h 03m 41.91s, Dec (J2000): +45d 42' 48.5". The preview images of 5 areas together with the 15 min.of arc area from SkyMap can be found in http://gua.db.ukr-vo.org/img/grb/101224A/index.html The images with full resolution are available via e-mail on demand. References: 1.L.Pakuliak DATABASE of GOLOSIIV PLATE ARCHIVE (DBGPA V2.0), http://gua.db.ukr-vo.org //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11620 SUBJECT: GRB101224A: EVLA Observations DATE: 11/02/01 04:37:41 GMT FROM: Ashley Zauderer at CfA A. Zauderer, E. Berger, and W. Fong (Harvard) report: We observed the position of the short GRB 101224A (GCN #11484) with the EVLA at 5 GHz for two hours starting on 2010 December 27.95 UT (3.72 days after the burst). No sources are detected within the XRT error circle (GCN #11488) to a 3-sigma limit of 156 microJy. We acknowledge the EVLA staff for their support of these observations.