GRB101225A

This page lists all entries on GRB101225A in GRBweb

Summary IPN Swift GCN 11493 GCN 11494 GCN 11495 GCN 11496 GCN 11497 GCN 11498 GCN 11499 GCN 11500 GCN 11501 GCN 11502 GCN 11503 GCN 11504 GCN 11505 GCN 11506 GCN 11507 GCN 11508 GCN 11519 GCN 11522 GCN 11550 GCN 11563 GCN 11564 GCN 11568 GCN 11570 GCN 11594 GCN 11642 GCN 11751 GCN 11770 GCN 11819

Summary table
Variable Value Source
T0 18:37:45 UTC GCN_circulars,Swift Det
ra 0.1980° Swift
decl 44.6003° Swift
pos_error 1.81e-04° Swift
T90 1088.0 s Swift
T90_start 18:37:45 UTC Swift
fluence 1.90e-06 erg/cm² Swift
redshift 0.4000 GCN_circulars,Swift-BAT Det
T100 1088.0 s
GBM_located False
mjd 55555.77621527778 GCN_circulars,Swift Det
IPN table
GRB_name GRB101225A
ra 0.2333°
decl 44.6000°
pos_error 5.00e-02°
redshift 0.8470
Swift table
GRB_name GRB101225A
t_trigger 18:37:45 UTC
ra 0.1980°
decl 44.6003°
pos_error 1.81e-04°
T90 1088.0 s
fluence 1.90e-06 erg/cm²
redshift 0.8470
GCN 11493 table
GRB_name GRB101225A
GCN_number 11493
Detection_method Swift Det
t_trigger 18:37:45 UTC
ra 0.2340°
decl 44.6020°
Circular_text TITLE: GCN CIRCULAR NUMBER: 11493 SUBJECT: Trigger 441015: Swift detection of a possible burst or transient DATE: 10/12/25 19:19:33 GMT FROM: Judith Racusin at GSFC J. L. Racusin (NASA/GSFC), A. P. Beardmore (U Leicester), S. Campana (INAF-OAB), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), O. M. Littlejohns (U Leicester), K. L. Page (U Leicester), B. Sbarufatti (INAF-OAB/IASFPA) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 18:37:45 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 101225A (trigger=441015). Swift slewed immediately to the burst. However, given that this was a 1088-second image trigger, the time from the trigger time (at the start of the image interval) to the XRT observation is over 23 minutes. The BAT on-board calculated location is RA, Dec 0.234, +44.602 which is RA(J2000) = 00h 00m 56s Dec(J2000) = +44d 36' 06" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Since this was an image trigger, the currently available BAT light curve does not show significant structure. The XRT began observing the field at 19:00:48.5 UT, 1383.0 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 0.1992, +44.6017 which is equivalent to: RA(J2000) = 00h 00m 47.80s Dec(J2000) = +44d 36' 06.1" with an uncertainty of 5.1 arcseconds (radius, 90% containment). This location is 89 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 data products have not been received at this time. The BAT trigger was an unusually long image trigger. Due to the relative proximity to the Galactic plane (l=113.55,b=-17.35), and lack of fading information from XRT at this time, we are unsure if this trigger is a GRB or transient. We will report as more information is available. Burst Advocate for this burst is J. L. Racusin (judith.racusin AT 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.)
GCN 11494 table
GRB_name GRB101225A
GCN_number 11494
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 11494 SUBJECT: GRB 101225A (Swift trigger 441015): optical upper limit DATE: 10/12/25 21:51:06 GMT FROM: Alexei Pozanenko at IKI, Moscow M. Andreev, A. Sergeev (Terskol Branch of Institute of Astronomy), A.Pozanenko (IKI) on behalf of larger GRB follow up collaboration report: We observed the field of the Swift trigger 441015 = GRB 101225A? (Racusin et al, GCN 11493) with Zeiss-600 telescope of Mt.Terskol observatory. In the XRT error circle (Racusin et al, GCN 11493) we do not detect any sources down to R=21.5 (3 sigma): UT (mid time), Exposure, Filter, ULimit 19:46 21 x 120s R 21.5 The combined image can be found at http://grb.eam.ru/Swift_441015/Trigger_441015_Zeiss600.jpg
GCN 11495 table
GRB_name GRB101225A
GCN_number 11495
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 11495 SUBJECT: Trigger 441015 / GRB 101225A: NOT optical afterglow candidate DATE: 10/12/25 22:12:53 GMT FROM: Dong Xu at Weizmann Inst D. Xu (Weizmann Inst.), I. Ilyin (AIP), J.P.U. Fynbo (DARK/NBI) report on behalf of a larger collaboration: We observed the field of GRB 101225A (Racusin et al., GCN 11493) at the Nordic Optical Telescope (NOT) equipped with StanCam. We obtained 3x300 s exposures in each of the V, R, and I filters, starting at 20:10:33.5 UT, 25/12/2010 (i.e., 1.54681 hrs after the BAT trigger). Within the XRT error circle only one optical source is detected in our images in each filter at coordinates (RA,Dec)(J2000) = (00:00:47.5, +44:36:02.4) (error-radius: 0.7 arcsec) This source lies on the southwestern border of the Swift/XRT error circle and not apparently extended. We found R=22.1+/-0.1 mag (calibrated with nearby USNO B1 stars) at 20:13:3.5 UT (i.e., 1.58847 hrs after the BAT trigger). Further NOT observation is undergoing in order to check the brightness variation of this source.
GCN 11496 table
GRB_name GRB101225A
GCN_number 11496
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 11496 SUBJECT: Trigger 441015 / GRB 101225A: Further NOT optical observation DATE: 10/12/26 01:24:57 GMT FROM: Dong Xu at Weizmann Inst D. Xu (Weizmann Inst.), I. Ilyin (AIP), J.P.U. Fynbo (DARK/NBI) report on behalf of a larger collaboration: We continued to observe the field of GRB 101225A (Racusin et al., GCN 11493) at the Nordic Optical Telescope (NOT) equipped with StanCam. We obtained 2x300 s exposures in each of the R and I filters, starting at 23:57:30.9 UT, 25/12/2010 (i.e., 5.32942 hrs after the BAT trigger). The optical source detected in our previous images (Xu et al., GCN 11495) is still present in the new stacked images for both R and I filters. We found m(R)=22.6+/-0.2 mag at 00:06:03 UT, 26/12/2010 (i.e., 5.47167 hrs after the BAT trigger), which shows that this object has decreased 0.5 mag in the R filter between the two epochs with a mean power-law decay index \alpha~0.4. The magnitude in the I filter, m(I)=21.6+/-0.2, largely remains unchanged. We thus conclude that this optical source is likely the afterglow of GRB 101225A. And further observation is encouraged.
GCN 11497 table
GRB_name GRB101225A
GCN_number 11497
Detection_method Swift-XRT Det
ra 0.1978°
decl 44.6003°
Circular_text TITLE: GCN CIRCULAR NUMBER: 11497 SUBJECT: GRB 101225A: Enhanced Swift-XRT position DATE: 10/12/26 04:03:25 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 6262 s of XRT Photon Counting mode data and 15 UVOT images for GRB 101225A, 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 = 0.19778, +44.60027 which is equivalent to: RA (J2000): 00h 00m 47.47s Dec (J2000): +44d 36' 01.0" with an uncertainty of 1.4 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 was automatically generated, and is an official product of the Swift-XRT team.
GCN 11498 table
GRB_name GRB101225A
GCN_number 11498
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 11498 SUBJECT: GRB 101225A: Swift-XRT refined Analysis DATE: 10/12/26 08:03:55 GMT FROM: Kim Page at U.of Leicester K.L. Page (U. Leicester) and J. L. Racusin (NASA/GSFC) report on behalf of the Swift-XRT team: We have analysed 13 ks of XRT data for possible GRB 101225A (Racusin et al., GCN Circ. 11493), from 1.4 ks to 35.6 ks after the BAT trigger. The data comprise 2.7 ks in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN. Circ 11497). The light curve shows substantial structure, but the underlying continuum can be modelled with a broken power-law decay. The initial decay index is alpha= 1.108 (+/-0.011). At T+21682 s the decay steepens to an alpha of 5.93 (+/-0.30). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.71 (+/-0.04). The best-fitting absorption column is 1.78 (+/-0.11) x 10^21 cm^-2, in excess of the Galactic value of 7.9 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 1.96 (+/-0.06) and a best-fitting absorption column of 1.58 (+0.16, -0.15) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.1 x 10^-11 (5.6 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.58 (+0.16, -0.15) x 10^21 cm^-2 Galactic foreground: 7.9 x 10^20 cm^-2 Excess significance: 17.1 sigma Photon index: 1.96 (+/-0.06) If the light curve continues to decay with a power-law decay index of 5.59, the count rate at T+24 hours will be 0.0007 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.7 x 10^-14 (3.7 x 10^-14) erg cm^-2 s^-1. We note that this is the brightest afterglow that the XRT has ever observed at a few thousand seconds after the trigger. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00441015. This circular is an official product of the Swift-XRT team.
GCN 11499 table
GRB_name GRB101225A
GCN_number 11499
Detection_method Swift-UVOT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 11499 SUBJECT: GRB 101225A: Swift/UVOT Detection DATE: 10/12/26 16:20:36 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and J. L. Racusin (NASA/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 101225A 1387 s after the BAT trigger (Racusion et al., GCN Circ. 11493). We find a marginal detection in the later data consistent with the enhanced XRT position (Evans et al., GCN Circ. 11497). Preliminary 3-sigma upper limits and magnitudes using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag V 1387 1705 58 >19.11 V 5572 29944 2601 >21.40 B 1485 1655 38 >19.84 B 5161 28991 3933 21.73+-0.29 U 1460 1630 38 >19.35 U 4955 7534 507 >20.68 UVW1 1435 1754 58 >19.25 UVW1 5982 7413 393 20.58+-0.37 UVM2 1410 1729 58 >18.74 UVM2 5777 7208 393 20.12+-0.34 UVW2 1512 1680 38 >18.82 UVW2 5367 6798 393 19.67+-0.22 UVW2 11650 12550 885 20.35+-0.22 UVW2 17470 18370 885 19.62+-0.15 UVW2 23218 29897 1771 20.10+-0.14 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.10 in the direction of the burst (Schlegel et al. 1998).
GCN 11500 table
GRB_name GRB101225A
GCN_number 11500
Detection_method Swift-BAT Det
ra 0.2037°
decl 44.5739°
Circular_text TITLE: GCN CIRCULAR NUMBER: 11500 SUBJECT: GRB 101225A, Swift-BAT refined analysis DATE: 10/12/26 17:20:01 GMT FROM: Hans Krimm at NASA-GSFC D. M. Palmer (LANL), 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), C. B. Markwardt (GSFC), J. L. Racusin (NASA/GSFC), 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-131 to T+1366 sec from the recent telemetry downlink, we report further analysis of Swift/BAT GRB 101225A (trigger #441015) (Racusin, et al., GCN Circ. 11493). The BAT ground-calculated position is RA, Dec = 0.2037, +44.5739 deg which is RA(J2000) = 00h 00m 48.9s Dec(J2000) = +44d 34' 26.0" with an uncertainty of 3.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 85%. The mask-tagged light curve shows that the GRB entered the BAT field of view at ~T-80 sec during a pre-planned slew. The flux slowly declined after this point and then increased at about T+600 seconds. There were less significant fluctuations until the end of the event data at about T+1300. T90 (15-350 keV) is 1088.0 +- 20.0 sec (estimated error including systematics). The time-averaged spectrum from T+0 to T+963 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.82 +- 0.32. The fluence in the 15-150 keV band is 1.9 +- 0.4 x 10-6 erg/cm2. The 1-sec peak photon flux measured from T+0.00 sec in the 15-150 keV band is 0.0 +- 0.0 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/441015/BA/
GCN 11501 table
GRB_name GRB101225A
GCN_number 11501
Detection_method Swift-XRT Other
redshift 0.0700
Circular_text TITLE: GCN CIRCULAR NUMBER: 11501 SUBJECT: Tentative redshift of GRB101225A (Christmas's burst) from Swift-XRT data DATE: 10/12/27 16:29:52 GMT FROM: Sergio Campana at INAF-OAB S. Campana (INAF-OAB), S. Covino (INAF-OAB), J.L. Racusin (NASA/GSFC) and K. L. Page (U Leicester) report on behalf of the Swift Team: GRB 101225A was detected by Swift BAT as an image trigger (Racusin al. 2010, GCN 11493). Swift XRT started observing 1383 s after the trigger observing the main event. The afterglow is very bright and the XRT remained in the Windowed Timing (WT) mode for two consecutive orbits. Within each orbit the spectrum remain constant as judged from the hardness ratio and from the power law photon index. We extract the XRT spectra for each of the first two orbits, separately. We then fit the two spectra within XSPEC using the model tbabs * ztbabs * (cutoff), keeping the same absorption pattern and leaving free the cutoff power-law model for the two spectra (the cutoff power-law model provides much better results in terms of column density evaluation with respect to a simple power-law model when small spectral variations are present). We assume a Galactic column density of 7.9x10^20 cm-2 (Kalberla et al. 2005, A&A 440 775) and we allow for a 30% uncertainty in the fit. We binned the spectra to 50 counts per energy bin and used the latest (v12) response matrix. The detection in the UVW2 filter by UVOT (Siegel & Racusin 2010, GCN 11499) constrains the redshift to be <1.4. The fit with the cutoff power-law is relatively good with a reduced chi^2 of 1.13 (508 dof). Motivated by the similarities with GRB 060218 (extremely long duration, soft prompt-emission spectrum, bright smoothly decaying X-ray afterglow light curve, UV detection with optical non-detection), we fit the X-ray spectrum including a blackbody component. The fit improves considerably (and the cutoff energy goes well above the XRT energy band, becoming unimportant for both spectra). The new fit provides a reduced chi^2 of 1.07 (504 dof), based on an F-test the addition of the blackbody component improves the fit by 4.2 sigma. In the intrinsic column density vs. redshift plane there is just one deep minimum hinting for a redshift z=0.07^+0.13_-0.04 (90% confidence level) and an intrinsic column density N_H(z)=(1.5^+0.5_-0.2)x10^21 cm^-2. The power law component shows a small softening from the first to the second orbit, with a photon index around 2.2-2.4. The blackbody component is hot with a temperature of ~1 keV, consistent among the two observations. The blackbody radius decreases from the first observation to the second from ~2x10^10 cm to ~0.6x10^10 cm. Ground-based optical follow-up observations are strongly encouraged in order to get spectroscopic confirmation for the redshift estimate and, eventually, to monitor the coming out of a supernova.
GCN 11502 table
GRB_name GRB101225A
GCN_number 11502
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 11502 SUBJECT: GRB 101225A: WHT observations DATE: 10/12/27 19:18:03 GMT FROM: Klaas Wiersema at U of Leicester K. Wiersema, N. Tanvir (Leicester) and A. Levan (Warwick) report: We observed the afterglow of GRB 101225A (Racusin et al. GCN 11493; Xu et al. GCN 11496) with the 4.2m William Herschel Telescope. We used the ACAM instrument to obtain imaging in r and i filters, and low resolution spectroscopy. The afterglow is clearly detected in individual images of 300 second exposure, at R=22.8 +/- 0.2 mag (uncertainties are dominated by scatter in USNO-B star magnitudes), at 28.2 hrs after burst. The source appears pointlike, in the 1.1 arcsecond seeing conditions. We note that this magnitude compared with the Xu et al value (GCN 11496) implies a very shallow decay. We obtained two low resolution spectra immediately following the imaging, each with 1200 second exposure time. Continuum emission is detected in the 5000 - 9300 A range, but no significant emission or absorption lines are detected. Detection of continuum up to 5000 A gives a formal constraint on the redshift of z<3.1. At the redshift estimated by Campana et al. (GCN 11501) we would expect to detect emission lines in the ACAM spectra (e.g. Balmer lines, [O III]), implying that the spectrum is either strongly dominated by the afterglow (the host is faint) or that the emission lines are redshifted into wavelength areas dominated by strong skylines. We thank Ovidiu Vaduvescu for excellent support.
GCN 11503 table
GRB_name GRB101225A
GCN_number 11503
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 11503 SUBJECT: GRB 101225: Optical follow-up of the Christmas burst DATE: 10/12/28 13:07:20 GMT FROM: Antonio Deugarte at IAA-CSIC C. C. Thoene, J. Gorosabel, S. Guziy, P. Kubnek, A. J. Castro-Tirado (IAA-CSIC), A. de Ugarte Postigo (DARK-NBI) and D. Xu (Weizmann Institute) report: "We observed the afterglow of the "Christmas burst" GRB 101225A (GCN 11493, Racusin et al.) on Dec. 26, starting 18:49 UT (1.008 days after the burst onset) with the 1.23m telescope at the Spanish-German Calar Alto Observatory in Southern Spain. Observations were obtained in V, R and I with total exposure times of 21x180s, 19x180s and 17x180s respectively. From the stacked images we obtain the following preliminary magnitudes for the optical afterglow (GCN 11495, Xu et al.) based on calibrations with Landolt standard stars taken immediately after the observations: V = 23.1 R = 22.2 I = 21.3 with errors of about 0.2 mag. This would imply that the afterglow has rebrightened after the first day (GCNs 11495 and 11496, Xu et al.) and, considering the possible low redshift of the GRB from the bright X-ray afterglow (GCN 11501, Campana et al.), this could be due to the onset of the accompanying SN, similar to the case of GRB 060218 (Campana et al. 2006). It is more significant if we consider the fast decay that is observed in X-rays (GCN 11498 Page et al.). We note that the magnitude reported by Wiersema et al. (GCN 11502) shows a shallow decay at a similar epoch, implying that there could be a problem of cross calibration of the different photometries or a non smooth behavior. In any case the evolution of the optical light curve would be rather flat, compared to other GRB light curves. Further follow up observations are planned."
GCN 11504 table
GRB_name GRB101225A
GCN_number 11504
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 11504 SUBJECT: GRB 101225A Late-time emission observed by Swift-BAT DATE: 10/12/29 01:38:52 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (GSFC/UMBC) and T. Sakamoto (GSFC/UMBC) on behalf of the Swift-BAT team: We report further results of BAT observations of GRB 101225A (Racusin, et al., GCN Circ. 11493). The most intense emission observed by BAT from GRB 101225A in the 14-50 keV range occurred from T+1372 to T+1672 seconds, later than previously reported (Palmer, et al. GCN circ #11500). The source was not in the BAT field of view from T-4500 to T-100 sec, from T+1088 to T+1372 sec, and from T+1758 to T+4936 sec. There was no detectable emission prior to T-4500 sec, and the burst appears to have started sometime before the source entered the BAT field of view at T-100 sec. The spectrum from T+1372 to T+1672 seconds is similar to the earlier report, with a single power law photon index of 1.87 +- 0.21. The total fluence was greater, possibly much greater, than 3 x 10^-6 ergs/cm^2 or about 1.6 times the fluence reported earlier. BAT detection of extremely long emission is similar to that of GRB 060218 and GRB 100316D (both spectroscopically confirmed SN-GRBs).
GCN 11505 table
GRB_name GRB101225A
GCN_number 11505
Detection_method MAXI Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 11505 SUBJECT: GRB 101225A: MAXI/GSC observations DATE: 10/12/29 05:38:26 GMT FROM: Nobuyuki Kawai at Tokyo Tech M. Serino, T. Mihara, Y.E. Nakagawa, M. Sugizaki, T. Yamamoto, T. Sootome, M. Matsuoka (RIKEN), N. Kawai, M. Morii, K. Sugimori, R. Usui (Tokyo Tech), K. Kawasaki, S. Ueno, H. Tomida, M. Kohama, M. Ishikawa (JAXA), A. Yoshida, K. Yamaoka, S. Nakahira (AGU), H. Tsunemi, M. Kimura (Osaka U.), H. Negoro, M. Nakajima H. Ozawa, F. Suwa (Nihon U.), Y. Ueda, N. Isobe, S. Eguchi, K. Hiroi (Kyoto U.), A. Daikyuji (Miyazaki U.), K. Yamazaki, A. Uzawa, T. Matsumura (Chuo U.), report on behalf of the MAXI team: MAXI/GSC observed the field of the Swift trigger 441015 = GRB 101225A (Racusin et al, GCN 11493) before and after the trigger time. The transit times (UT) and the observed fluxes in 2-10 keV energy band are 15:51 (T-9988s) -19 +- 11 mCrab 17:23 (T-4483s) 20 +- 13 mCrab 18:54 (T+1002s) 20 +- 15 mCrab 20:05 (T+5218s) 11 +- 9 mCrab 23:08 (T+16209s) 2 +- 7 mCrab All the quoted uncertainties are 1-sigma statistical errors. Note that the third transit occurred within the 1088-second Swift image trigger interval. While it is not statistically significant, there appears be a weak X-ray enhancement at the location of the Swift trigger position during or near the BAT detection times (Cummings and Sakamoto, GCN 11504).
GCN 11506 table
GRB_name GRB101225A
GCN_number 11506
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 11506 SUBJECT: GRB 101225A: P60 Observations DATE: 10/12/29 18:32:50 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (UC Berkeley) reports on behalf of a larger collaboration: We have imaged the field of GRB101225A (Racusin et al., GCN 11493) with the automated Palomar 60 inch telescope. Images were obtained in the Sloan r' and i' filters on 2010 December 28 beginning at 01:49 UT (~ 55.2 hours after the BAT trigger time). We detect a faint source at the location of the optical afterglow (Xu et al., GCN 11495) in both filters. Using a set of nearby sources from the USNO-B1 catalog for reference, we measure the following magnitudes for the source at this time: R = 22.8 +/- 0.2; I = 22.3 +/- 0.2. Our R-band measurement is consistent with that found by Wiersema et al (GCN 11502) at t ~ 28 hours, but fainter (in both R and I) than the values reported by Thoene at al (GCN 11503) at a similar time. In either case, we find no evidence for a re-brightening as of yet, as would be expected for the emergence of supernova emission from a nearby event like GRB060218/SN2006aj.
GCN 11507 table
GRB_name GRB101225A
GCN_number 11507
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 11507 SUBJECT: GRB 101225A: MMT spectroscopy DATE: 10/12/29 23:09:32 GMT FROM: Ryan Chornock at Harvard R. Chornock, G. H. Marion, G. Narayan, E. Berger, and A. M. Soderberg (Harvard/CfA) report: We obtained spectroscopy of the optical source (Xu et al., GCN 11495; Xu et al., GCN 11496; Siegel et al., GCN 11499; Wiersema et al., 11502; Thoene et al., 11503; Cenko et al., 11506) associated with GRB 101225A (Racusin et al., GCN 11493) using the Blue Channel Spectrograph on the 6.5-m MMT. Two 2400 s observations starting on December 29.1 UT covered the spectral range 3175-8385 Angstroms. The source has a smooth blue continuum and no clear emission or absorption features associated with a host galaxy are detected in our spectra, similar to the findings of Wiersema et al. (GCN 11502). In addition, the continuum has no obvious broad undulations or evidence for line blanketing shortward of 4000 Angstroms, such as would be expected if the spectral features of a supernova were emerging. The spectrum is well fit by a power law of the form F_nu ~ constant * nu^(0.4), which is bluer than typical afterglow spectra, which typically scale as F_nu ~ nu^(-0.6).
GCN 11508 table
GRB_name GRB101225A
GCN_number 11508
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 11508 SUBJECT: GRB 101225A: optical break from NOT observation DATE: 10/12/31 01:43:13 GMT FROM: Dong Xu at Weizmann Inst D. Xu (Weizmann Inst.), P. Hakala (Turku U.), J.P.U. Fynbo (DARK/NBI) report on behalf of a larger collaboration: We imaged the filed of GRB(or XRF) 101225A (Racusin et al., GCN 11493) at the Nordic Optical Telescope (NOT) equipped with either StanCam or ALFOSC in B, V, R, and I filters. The R-band optical afterglow (Xu et al., GCN 11495) light curve was found decaying very slowly from m(R)=22.6 +/- 0.2 at 5.47167 hrs after the BAT trigger to m(R)=22.8 +/- 0.2 at 55.2 hrs after the BAT trigger (Xu et al., GCN 11496; Wiersema et al., GCN 11502; Thoene et al., GCN 11503; Cenko, GCN 11506). Two 450 s R-band images were obtained with NOT/ALFOSC, starting at 21:50:46.9 UT, 30/12/2010 (i.e., 123.217 hrs after the BAT trigger) under the conditions of seeing ~1". The afterglow was clearly detected in the stacked image, largely pointlike, and had m(R)=23.3+/-0.2. This indicates that R-band afterglow is now decaying faster compared with its behavior during the past days, and that the host hasn't dominated the brightness, being consistent with the featureless spectroscopy (Wiersema et al., GCN 11502; Chornock et al., 11507).
GCN 11519 table
GRB_name GRB101225A
GCN_number 11519
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 11519 SUBJECT: GRB 101225A: Host galaxy DATE: 11/01/05 13:44:53 GMT FROM: Dong Xu at Weizmann Inst D. Xu (Weizmann Inst.), D. Malesani, J.P.U. Fynbo, J. Hjorth (DARK/NBI), P. Jakobsson (U. Iceland), T. Augusteijn (NOT), report on behalf of a larger collaboration: We imaged the field of GRB 101225A (Racusin et al., GCN 11493) at the Nordic Optical Telescope (NOT) equipped with ALFOSC. We obtained 6x600 s R-band images with a good seeing ~0.7" and little cloud cover. Observations started at 20:55:25 UT on 2011 Jan 4 (i.e., 10.1 days after the BAT trigger). The optical counterpart of the burst (Xu et al., GCN 11495) has faded further and it is detected in the stacked image with R = 24.1+/-0.1, calibrated against the USNO-B1 star #1345-0000324. The object is now significantly extended along the northwest-southeast direction, indicating a significant contribution from the underlying host galaxy. Further observations are encouraged, especially in the NIR.
GCN 11522 table
GRB_name GRB101225A
GCN_number 11522
Detection_method Swift-BAT Det
redshift 0.4000
Circular_text TITLE: GCN CIRCULAR NUMBER: 11522 SUBJECT: GRB 101225A: Keck redshift DATE: 11/01/06 20:13:40 GMT FROM: Dong Xu at Weizmann Inst D. Xu, A. Gal-Yam (WIS), J. P. U. Fynbo (DARK/NBI), report on behalf of a large collaboration: Spectroscopy of the host galaxy of GRB 101225A (Racusin et al., GCN 11493; Xu et al. GCN 11519) was carried out at the 10m Keck-I telescope equipped with the Low Resolution Imaging Spectrometer (LRIS) around 10 UT, 6th Jan. 2011, with a good seeing ~0.7". A 900s spectrum was obtained and it consists of a red and a blue channels, covering ~3200-5500 A and ~5000-8200 A, respectively. The spectrum has a low signal-to-noise ration and the trace is best detected in the red channel. Three weak emission lines are found at a common redshift of z=0.40, considered as Hbeta (4861 AA), and the O III (4960 AA, 5007 AA). Isotropic energy: >~ 7.8+/-1.6 x10^50 erg, using the BAT fluence (Palmer et al., GCN 11500) The absence of evidence for an emerging SN at the above redshift suggests that GRB 101225A is a SN-less or SN-weak long GRB event. Further deep spectroscopic observations are encouraged.
GCN 11550 table
GRB_name GRB101225A
GCN_number 11550
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 11550 SUBJECT: GRB 101225a DATE: 11/01/10 08:29:09 GMT FROM: Dale A. Frail at NRAO Dale A. Frail (NRAO) reports on behalf of a larger collaboration: "We observed GRB 101225A (GCN#s 11494, 11497, 11498, 11499, 11500) with the Expanded Very Large Array (EVLA) on 2011 January 6.99 UT using the C-band wide receiver (frequency range 4-8 GHz). No significant radio signal is detected at the enhanced Swift-XRT position (GCN 11497) at frequencies of 4.5 and 7.9 GHz and at 3-sigma levels of 42 uJy and 30 uJy, respectively. No further observations are planned.
GCN 11563 table
GRB_name GRB101225A
GCN_number 11563
Detection_method retraction
redshift 0.4000
Circular_text TITLE: GCN CIRCULAR NUMBER: 11563 SUBJECT: GRB 101225A: Redshift retraction and results of additional photometric follow-up at the NOT DATE: 11/01/13 11:12:38 GMT FROM: Dong Xu at Weizmann Inst J. P. U. Fynbo (DARK/NBI), D. Xu (WIS) report on behalf of a larger collaboration: We re-analyzed the 900s low signal-to-noise spectrum reported in our previous GCN #11522. We found that the brightest of the three weak emission features is due to bad removal of a cosmic ray hit. The two other features are close to sky emission lines. We thus conclude that the reported redshift of z=0.4 in GCN #11522 for this event is not secure and may be wrong. Deep spectroscopic observations from 8-10 m telescopes are strongly encouraged. We apologize for the confusing this report may have caused. We also continued photometric follow-ups of the optical counterpart of GRB 101225A at NOT, and obtained 6x600 s R-band images on Jan. 9 with a good seeing ~0.65". The object decayed to m(R)=24.5+/-0.2 compared to m(R)=24.1+/-0.1 on Jan. 5 in GCN #11519. However, this time it was largely pointlike, which is at odds with being found significantly extended along the northwest-southeast direction on Jan. 5. The decay in brightness and the variation in morphology indicates that the underlying host galaxy, if any, still hasn't dominated the optical counterpart. Further photometric and spectroscopic observations are underway.
GCN 11564 table
GRB_name GRB101225A
GCN_number 11564
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 11564 SUBJECT: GRB 101225A: HST observations - no host detected DATE: 11/01/13 12:46:08 GMT FROM: Nial Tanvir at U.Leicester N.R. Tanvir (U. Leicester), A.J. Levan (U. Warwick), J.P.U. Fynbo, D. Malesani, J. Hjorth (DARK/NBI), D. Xu, A. Gal-Yam (Weizmann Inst.) K. Wiersema, P.A. Evans (U. Leicester) & D.F. Bersier (Liverpool JMU) report: We observed the location of GRB 101225A (Racusin et al. GCN 11493; Xu et al. GCN 11495) using HST/ACS on 2011 Jan 13 beginning at 00:25 UT, approximately 18 days post-burst. Images were obtained in the F606W and F435W filters. Contrary to the claim in Xu et al. (GCN 11519), we find no evidence for extension in either image, and thus no indication of a host galaxy. We do, however, find the colour of the optical transient is now quite red with an (AB) colour of F435W-F606W=1.6, confirming the reddening trend from the initially very blue colour (Chornock et al. GCN 11507). The magnitude (F606W(AB)=24.6) is consistent with a continuing post-break power-law decline in the R-band with a slope t^-1. We note that if this event is at a redshift as low as z=0.07, as suggested by an analysis of the X-ray data (Campana et al. GCN 11501), then any host galaxy beneath the transient would have to be both very faint (less than about M_R=-12) and compact not to be seen in the HST images. We thank the STScI staff for rapidly implementing these observations. [GCN OPS NOTE(13jan11): Per author's request, DX was added to the autor list.]
GCN 11568 table
GRB_name GRB101225A
GCN_number 11568
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 11568 SUBJECT: The Christmas burst GRB 101225A - optical spectroscopy with GTC DATE: 11/01/14 17:35:27 GMT FROM: Antonio Deugarte at IAA-CSIC C. C. Thoene, S. Guizy, A. Castro-Tirado, J. Gorosabel (IAA-CSIC) and A. de Ugarte Postigo (DARK/NBI) report: We observed the optical counterpart of GRB 101225A (the Christmas burst, GCN 11493, Racusin et al.) with OSIRIS at the 10.4m GTC on Dec. 27, starting at 21:20 UT (51h after the trigger). We obtained 2 exposures of 1800s using grism R300B. We acknowledge the excellent support from the GTC staff. The combined and flux-calibrated spectrum shows a smooth, very blue continuum without any absorption of emission features, consistent with the spectral observations from WHT (GCN 11502, Wiersema et al.), MMT (GCN 11507, Chornock et al.) and Keck/LRIS (GCN 11563, Fynbo et al.) at different times after the trigger. The continuum is well fitted using a power law with F(nu) = nu^(0.9+/-0.5). Considering the very flat optical light curve, the apparent color changes in the optical SED, the shape of the X-ray spectrum (GCN 11501, Campana et al.) and the lack of a host galaxy (GCN 11564, Tanvir et al.), we think that this object might not be a GRB but rather a compact object from the MW or the local group. Further follow-up is encouraged to determine the nature of this peculiar object. [GCN OPS NOTE(14jan11): Per author's request, the last sentence in the first paragraph was added.]
GCN 11570 table
GRB_name GRB101225A
GCN_number 11570
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 11570 SUBJECT: GRB101225A - timing analysis DATE: 11/01/15 11:46:51 GMT FROM: Nial Tanvir at U.Leicester N.R. Tanvir, P.A. Evans, O.M. Littlejohns (U. Leicester), A.J. Levan (U. Warwick) report: In light of the continuing uncertainty about the nature of GRB 101225A, we performed a search for any periodic signal in the BAT and XRT light curves for this event. In neither case do we find any significant periods in the data: from ~0.01 Hz (100 s periods) to ~100 Hz (0.01 s periods) in the case of BAT (data from 50-900 s post-trigger), and from ~0.004 Hz (250 s periods) to ~1 Hz in XRT (2nd orbit data).
GCN 11594 table
GRB_name GRB101225A
GCN_number 11594
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 11594 SUBJECT: GRB 101225A: CQUEAN optical observation DATE: 11/01/22 15:52:20 GMT FROM: Won-Kee Park at Seoul Nat U/Dept.Physics and Astronomy/CEOU Won-Kee Park, Myungshin Im, Changsu Choi (Seoul National Univ.), Hyeonju Jeong, Juhee Lim, and Soojong Pak (Kyung Hee Univ.) The field of GRB 101225A was observed with CQUEAN, an optical CCD camera attached at the 2.1m telescope at McDonald Observatory, USA. The observation was carried out from 01:16:23 UT, Dec. 26, 2010, with i, r, z, and Y filters, with exposures of 3 * 300 secs for each band. The afterglow was clearly visible on i and r-band images at the same position reported by Xu et al.(GCN 11495). We obtained the preliminary magnitude of the afterglow on the stacked i-band image calibrated with the neighboring USNO B-1.0 stars: R = 22.60 +- 0.19 at 01:42:47 UT. Further analysis of the data is ongoing.
GCN 11642 table
GRB_name GRB101225A
GCN_number 11642
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 11642 SUBJECT: GRB 101225A is likely at z~0 DATE: 11/02/05 10:52:36 GMT FROM: Andrew Levan at U.of Leicester A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester) report for a larger collaboration: We obtained imaging of GRB 101225A (Racusin et al. GCN 11493) with GMOS on Gemini North on 5 Feb 2011. At this epoch we obtained a total of 2400s in a narrow band H-alpha filter (centered a z~0) and 900s in the r-band. The afterglow is weakly detected in the H-alpha image, but not in the contemporaneous r-band imaging. This suggests substantial spectral evolution from the early-time spectroscopy (Chornock et al. GCN 11507), and that line emission is now contributing significantly to the emission between 6000-7000A. Given the absence of any host galaxy, and the extremely unusual characteristics of this event, the most natural explanation is that we are detecting Ha at z~0 from some class of high-energy transient. If that is the case, three possible locations seem most likely: (a) it could be a source within the Milky Way, sufficiently far away that the progenitor was undetected in prior imaging, (b) it could be in the far halo of M31 at a distance of at least ~115 kpc (c) it could be associated with the distant Local Group dwarf spheroidal galaxy Andromeda XVIII, which itself is located ~1.4 Mpc from us, but is only ~12 kpc from the line of sight to 101225A. We note that the early optical and X-ray emission (in particular the ratio of the two) remain extremely unusual for known Galactic transients. We thank the staff of Gemini North for the rapid and effective execution of these observations.
GCN 11751 table
GRB_name GRB101225A
GCN_number 11751
Detection_method Other
ra 0.1978°
decl 44.6003°
Circular_text TITLE: GCN CIRCULAR NUMBER: 11751 SUBJECT: GRB 101225A, the review of the sky area in plate archives DATE: 11/02/20 13:39:08 GMT FROM: Valentyna Golovnya at Main Astro Obs,Kyiv GRB 101225A, 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 101225A (P.A. Evans et al., GCN 11497) 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 have been placed into Golosiiv Plate Archive database DBGPA with open access to them. No any object has been found in the point with the mentioned coordinates of GRB. The list of plates is given in the table: YYYYMMDD UT Plates Exp. LimMag 19850815 00:26:01 GUA040C000702A 16.0 16.15 19841212 16:51:23 GUA040C000587 16.0 15.35 19840827 23:46:55 GUA040C000468A 16.0 15.35 19930923 21:33:33 GUA040C002237 18.0 15.35 19840827 23:12:28 GUA040C000467A 16.0 16.10 19840905 22:33:06 GUA040C000491 18.0 16.35 19850815 00:02:05 GUA040C000701 16.0 16.15 19871024 19:40:17 GUA040C001153A 18.0 15.35 19840809 01:08:44 GUA040C000441 16.0 14.10 19840905 22:58:22 GUA040C000492A 18.0 16.55 Plates: the plate's identifier in GUA040C archive of DWA (D/F=400/2000, M=103"/mm) of the Ukrainian NAS Main Astro obs in Kyiv (Marsden's number - 83)[1]. Exp. - Duration of the maximum exposure (minutes). LimMag - Limited V mag, derived in the 15 minutes area around the location given in P.A. Evans et al., GCN 11497: RA (J2000): 00h 00m 47.47s, Dec (J2000): +44d 36' 01.0". The preview images of 10 areas together with the 15 min.of arc area from SkyMap can be found in http://gua.db.ukr-vo.org/img/grb/101225A/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
GCN 11770 table
GRB_name GRB101225A
GCN_number 11770
Detection_method VLA Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 11770 SUBJECT: GRB101225A: early EVLA Observations of Christmas Burst DATE: 11/03/03 05:05:26 GMT FROM: Ashley Zauderer at CfA A. Zauderer, E. Berger, and W. Fong (Harvard) report: We observed the position of the Christmas GRB 101225A for 32 minutes with the EVLA at a frequency of 5 GHz on 2010 December 30.03, less than five days after the burst (GCN 11493). We find no significant radio source at the XRT position (GCN 11497) to a 3-sigma upper limit of 60 microJy. We thank the EVLA staff for their support of these observations over the holidays.
GCN 11819 table
GRB_name GRB101225A
GCN_number 11819
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 11819 SUBJECT: GRB 101225A: revised analysis of narrow band imaging DATE: 11/03/22 19:16:23 GMT FROM: Nial Tanvir at U.Leicester N. R. Tanvir (U. Leicester) and A. J. Levan (U. Warwick) report: We have re-reduced and re-analysed more thoroughly the imaging reported in GCN 11642. While it remains the case that the optical transient is detected in the H-alpha narrow-band filter, and at best marginally present in the r-band, the significance of the excess H-alpha detection is reduced. Within the associated errors the revised photometry is broadly consistent with the red colour of the transient at this time (the narrow-band filter being somewhat redward of the central wavelength of the r-band filter), and hence, the data do not require significant line emission. This argument for a z~0 origin is therefore weakened.