//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17229 SUBJECT: GRB 141225A: Swift detection of a burst DATE: 14/12/25 23:28:25 GMT FROM: Hans Krimm at NASA-GSFC P. D'Avanzo (INAF-OAB), A. P. Beardmore (U Leicester), M. G. Bernardini (INAF-OAB), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), A. Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB), C. J. Mountford (U Leicester) and J. L. Racusin (NASA/GSFC) report on behalf of the Swift Team: At 23:01:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 141225A (trigger=622476). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 138.751, +33.795 which is RA(J2000) = 09h 15m 00s Dec(J2000) = +33d 47' 41" 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 30 sec. The peak count rate was ~1600 counts/sec (15-350 keV), at ~6 sec after the trigger. The XRT began observing the field at 23:08:10.5 UT, 423.5 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 138.7782, 33.7919 which is equivalent to: RA(J2000) = 09h 15m 06.77s Dec(J2000) = +33d 47' 30.7" with an uncertainty of 2.1 arcseconds (radius, 90% containment). This location is 82 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.48 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 1.6 (+1.62/-1.47) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 440 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 8'x 8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Merry Christmas from the Swift Team! Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT brera.inaf.it). 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: 17230 SUBJECT: GRB 141225A: 1.23m CAHA optical observations DATE: 14/12/25 23:52:18 GMT FROM: Javier Gorosabel at IAA-CSIC J. Gorosabel (IAA-CSIC/UPV-EHU), S. Hellmich (DLR), A. de Ugarte Postigo (IAA-CSIC), S. Mottola (DLR), C. Thoene (IAA-CSIC), report on behalf of a larger collaboration: "We observed the field of GRB 141225A (D'Avanzo et al. GCN 17229) with the 1.23m CAHA telescope in the I-band starting at 23:07:27.7 UT (starting ~6.5 min post burst). We detected an optical source located at RA(J2000)=09:15:06.93, DEC(J2000)=33:47:30.8 (+/-1") with a very estimative magnitude of I~18.5 (Vega) consistent with the XRT position." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17231 SUBJECT: GRB 141225A: LT optical candidate DATE: 14/12/25 23:58:02 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (U. Ferrara), J. Japelj (U. Ljubljana), A. Melandri (INAF-OAB) on behalf of a large collaboration reports: The 2-m Liverpool Telescope automatically began observing Swift GRB 141225A (D'Avanzo et al. GCN 17229). Within the XRT error circle we found an uncatalogued object at the following position: RA(J2000) = 09:15:06.92 Dec(J2000)= +33:47:30.6 with r=20.3 +- 0.1 mag at 36 minutes post trigger, calibrated against SDSS nearby stars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17232 SUBJECT: GRB 141225A: Optical aftergow confirmation DATE: 14/12/26 00:05:51 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani (DARK/NBI), T. Augusteijn (NOT), and P. Jakobsson (Univ. Iceland) report on behalf of a larger collaboration: We observed the field of GRB 141225A (D'Avanzo et al., GCN 17229) with the Nordic Optical telescope equipped with the MOSCA camera. Observations started at 23:25:08 UT (0.40 hr after the GRB trigger) and were conducted in the SDSS r band. Consistent with the XRT position (see http://www.swift.ac.uk/xrt_positions/), we detect a bright source not present in the DSS, which is likely the optical afterglow of GRB 141225A. Its coordinates are (J2000): RA = 09:15:06.89 Dec = +33:47:30.8 and an approximate magnitude of R ~ 19.5 (Vega; assuming R = 16.2 for the USNO star at RA = 09:15:09.46, Dec = +33:47:48.7). This is the same source reported by Gorosabel et al. (GCN 17230) and Guidorzi et al. (GCN 17231). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17233 SUBJECT: GRB 141225A: UVOT detection DATE: 14/12/26 02:16:13 GMT FROM: Paul Kuin at MSSL N.P.M. Kuin (MSSL/UCL) and P. D'Avanzo (INAF-OAB) report on behalf of the Swift Team UVOT took a finding chart exposure of 150 seconds with the White filter starting 427 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 09:15:06.92 = 138.77885 DEC(J2000) = +33:47:30.9 = 33.79191 with a 90%-confidence error radius of about 0.66 arc sec. This position is 2.3 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.66 with a 1-sigma error of about 0.08. A second exposure of 150 seconds in the White filter starting 858 seconds after the BAT trigger has an estimated magnitude of 19.61 with a 1-sigma error of about 0.16, showing a clear decay. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17234 SUBJECT: GRB 141225A: Redshift from OSIRIS at the 10.4m GTC DATE: 14/12/26 03:08:38 GMT FROM: Javier Gorosabel at IAA-CSIC J. Gorosabel (UPV-EHU, IAA-CSIC), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C.C. Thoene (IAA-CSIC), N. Tanvir (U. Leicester), J.P.U. Fynbo (DARK/NBI), D. García-Alvare (GTC), "A. Perez-Romero (GTC) report on behalf of a larger collaboration: We observed the afterglow of GRB 141225A (D'Avanzo et al. GCN 17229) with OSIRIS at the 10.4m GTC. Observations began at 00:25:25 UT (~1.4 hours post burst). Four 600s spectra were taken with the R1000B grism going from 3750 to 7800 AA. A first analisys based on archival arc lamps reveals absorption features of FeII and MgII at a preliminary redshift of z=0.915. [GCN OPS NOTE(27dec14): Pera author's request, D.G was changed to D.G-A and A.P-R was added.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17235 SUBJECT: GRB 141225A: Enhanced Swift-XRT position DATE: 14/12/26 04:07:30 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 1893 s of XRT Photon Counting mode data and 4 UVOT images for GRB 141225A, 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 = 138.77827, +33.79184 which is equivalent to: RA (J2000): 09h 15m 6.79s Dec (J2000): +33d 47' 30.6" with an uncertainty of 1.6 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17236 SUBJECT: GRB 141225A: Nanshan very early optical observations DATE: 14/12/26 06:39:37 GMT FROM: Dong Xu at DARK/NBI D. Xu (DARK, NAOC) and X. Gao (Urumqi No.1 Senior High School, Xinjiang) report: We observed the field of GRB 141225A (D'Avanzo et al., GCN 17229) using the 36cm robotic telescope located at Nanshan, Xinjiang, China. Observations started at 23:04:14 UT on 2014-12-25, i.e., 187 s after the burst, and subsequently 3x40s, 4x60s, and 12x90s unfiltered images were obtained. The optical afterglow (Gorosabel et al., GCN 17230; Guidorzi et al., GCN 17231; Malesani et al., GCN 17232; Kuin & D'Avanzo, GCN 17233) is detected in all 40s and 60s exposures and only in the beginnings of 90s exposures, and is evident of decaying. The afterglow has m(R)~17.2 from the first 40s image (i.e., 187 s - 227 s post-burst), calibrated with R-band magnitudes of nearby SDSS stars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17237 SUBJECT: GRB 141225A: MASTER-SAAO first OT detection DATE: 14/12/26 10:41:39 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs D.Buckley, S. Potter, A. Kniazev, M. Kotze South African Astronomical Observatory E. Gorbovskoy,V. Lipunov, N.Tyurina P.Balanutsa, D.Denisenko, M.Pruzhinskaya,A.Kuznetsov, V.Kornilov, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute O.Gres, K.Ivanov, S.Yazev, N.M.Budnev, V.A.Poleshchuk Irkutsk State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinsky, I.Zalozhnih, A. Popov Ural Federal University, Kourovka H. Levato and C. Saffe Instituto de Ciencias Astronomicas de la Tierra y del Espacio (ICATE), San Juan, Argentina C. Mallamacci, C. Lopez and F. Podest Observatorio Astronomico Felix Aguilar (OAFA), San Juan National University, Argentina MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru) installed several days ago in South African Astronomical Observatory (Sutherland) was automatically pointed to the Swift and Fermi GRB 141225A (Avanzo et. al. GCN 17229). Firstly MASTER-SAAO pointed by FERMI coordinates and made first exposure 28 sec. after FERMI trigger at 2014-12-25 23:02:28 UT. Then MASTER-SAAO pointed to the Swift coordinates 20 sec after Swift notice time and 113 sec after trigger time at 2014-12-25 23:03:00 UT in two polarizations. MASTER-SAAO discovered OT source (Gorosabel et. al. 17230, Malesani et. al 17232, Kuin et. al 17233, Xu et. al 17236): Ra: 09:15:06.94 Dec: +33:47:30.87 Mag: 17.5 The source is visible on the subsequent frames. The data reduction is continued. Our band is well described by a parity 0.8R+0.2B (USNO B1). This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17238 SUBJECT: GRB 141225A: Swift-XRT refined Analysis DATE: 14/12/26 14:28:04 GMT FROM: Phil Evans at U of Leicester A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), J.A. Kennea (PSU), V. Mangano (PSU), M.C. Stroh (PSU), K.L. Page (U. Leicester), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester) and P. D'Avanzo report on behalf of the Swift-XRT team: We have analysed 8.0 ks of XRT data for GRB 141225A (D'Avanzo et al. GCN Circ. 17229), from 434 s to 40.8 ks after the BAT trigger. The data comprise 33 s 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. 17235). The light curve can be modelled with an initial power-law decay with an index of alpha=2.22 (+0.32, -0.25), followed by a break at T+1770 s to an alpha of 1.12 (+0.26, -0.38). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.67 (+0.13, -0.12). The best-fitting absorption column is consistent with the Galactic value of 1.5 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.9 x 10^-11 (4.0 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.5 (+/-2.1) x 10^20 cm^-2 Galactic foreground: 1.5 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.67 (+0.13, -0.12) If the light curve continues to decay with a power-law decay index of 1.12, the count rate at T+24 hours will be 1.9 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.3 x 10^-14 (7.4 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00622476. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17239 SUBJECT: GRB 141225A: Swift-BAT refined analysis DATE: 14/12/26 14:29:58 GMT FROM: Hans Krimm at NASA-GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), P. D'Avanzo (INAF-OAB), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (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 141225A (trigger #622476) (D'Avanzo, et al., GCN Circ. 17229). The BAT ground-calculated position is RA, Dec = 138.754, 33.774 deg which is RA(J2000) = 09h 15m 01.1s Dec(J2000) = +33d 46' 27.7" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 26%. The burst location first entered the BAT field of view at ~T-40 sec, during a pre-planned slew. The mask-weighted light curve shows a single FRED-shaped peak, beginning at T+5 sec, peaking at T+12 sec and returning to baseline level by T+50 sec. T90 (15-350 keV) is 40.24 +- 7.04 sec sec (estimated error including systematics). The time-averaged spectrum from T+5.50 to T+50.68 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.32 +- 0.15. The fluence in the 15-150 keV band is 2.5 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+11.76 sec in the 15-150 keV band is 1.3 +- 0.4 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/622476/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17240 SUBJECT: GRB 141225A: very early T60 observations DATE: 14/12/26 16:15:01 GMT FROM: Eda Sonbas at NASA/GSFC E. Sonbas (Adiyaman Univ.), T. Guver (Istanbul Univ.), E. Gogus (Sabanci Univ.), M. Parmaksizoglu, M. Dindar, H. Kirbiyik (TUG) report on behalf of a larger collaboration We observed the field of Swift GRB 141225A (D'Avanzo et al., GCN#17229) with the 0.60 meter robotic T60 telescope (Dindar et al. 2014; Bakirlitepe, TUBITAK National Observatory, Turkey), starting December, 25, 23:03:16.37 UT (~ 129 second after the trigger). Observations were carried out with the R and B filters. The afterglow (Gorosabel et al., GCN 17230; Guidorzi et al., GCN 17231; Malesani et al., GCN 17232; Kuin & D'Avanzo, GCN 17233, Xu et al. GCN 17236, Buckley et al. GCN 17237) is clearly detected in the R band images with an exposure time of 60 s. Using USNO-B1 star USNO-B1 1237-0186662 (R.A.=138.789, Dec=+33.797) in the field, the R magnitudes of the OT were estimated as follows; t-t0 (sec) exp.(s) filt mag err (+/-) ~129 60 R 17.04 0.04 ~195 60 R 17.15 0.02 Further analysis are ongoing. We are grateful to TUBITAK National Observatory for a partial support in using T60 telescope with project number 539 and technical support. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17241 SUBJECT: GRB 141225A: Fermi GBM detection DATE: 14/12/26 17:48:26 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM Team: "At 23:01:13.82 UT on December 25 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 141225A (trigger 441241276/141225959), which was also detected by Swift (P. D'Avanzo et al. 2014, GCN 17229). Additionally, there were optical detections from the 1.23m CAHA telescope (J. Gorosabel et al. 2014 GCN 17230) among others as well as a redshift measurement (J. Gorosabel et al. 2014 GCN 17234). The GBM on-ground location, using the Fermi GBM trigger data, is consistent with the Swift/XRT and optical locations. The angle of the burst direction to the Fermi LAT boresight is 104 degrees. The GBM light curve consists of one FRED-like peak with a duration (T90) of about 56 s (50-300 keV). The time-averaged spectrum from T0-4.1s to T0+21.5s is well fit by a Band function with Epeak = 187 +/- 29 keV, Alpha = -0.35 +/- 0.17 and Beta = -2.0 +/- 0.1. The event fluence (10-1000 keV) in this time interval is (6.5 +/- 0.3)E-06 ergs/cm^2. The 1.0-sec peak photon flux measured starting from T0+9.7s in the 10-1000 keV band is 2.5 +/- 0.2 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: 17242 SUBJECT: GRB 141225A: Swift/UVOT refined analysis DATE: 14/12/26 18:37:57 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (UCL-MSSL) and P. D'Avanzo (INAF-OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 141225A 428 s after the BAT trigger (D'Avanzo et al., GCN Circ. 17229). The optical afterglow has been reported (Gorosabel et al, GCN Circ. 17230; Guidorzi et al., GCN Circ. 17231; Malesani et al., GCN Circ. 17232; Kuin & D'Avanzo, GCN.Circ. 17233; Xu et al., GCN Circ. 17236; Buckley et al., 17237; Sonbas et al., GCB Circ. 17240) with a redshift of z=0.915 (Gorosabel et al., GCN Circ. 17234). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 428 578 147 18.81 +/- 0.06 white 858 1008 147 19.76 +/- 0.10 v 735 1406 78 >19.2 b 660 1495 86 >19.5 u 636 1481 97 19.19 +/- 0.19 w1 611 1456 97 >19.0 m2 760 780 19 >18.6 w2 6480 6680 197 >19.7 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17243 SUBJECT: GRB 141225A: TAROT Calern observatory optical observations DATE: 14/12/27 00:45:35 GMT FROM: Alain Klotz at IRAP-CNRS-OMP Klotz A. (IRAP-CNRS-OMP), Gendre B. (IRAP-CNRS-OMP), Boer M., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 141225A detected by SWIFT (trigger 513505) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 8.2 min after the GRB trigger. The elevation of the field increased from 50 degrees above horizon and weather conditions were good. We co-added a series of exposures to measure the optical afterglow discovered by Gorosabel et al. (GCNC 17230): Tstart Tend (sec) (sec) Rmag +/- 496 907 18.8 0.3 918 1315 19.0 0.3 1327 1728 19.9 0.5 The afterglow is no longer detected in the next images. Magnitudes were estimated using USNO-B1 star USNO-B1 1237-0186662 (R.A.=138.789, Dec=+33.797) as Sonbas et al. (GCNC 17240). Magnitudes are not corrected for galactic dust extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17244 SUBJECT: GRB 141225A: MITSuME Okayama upper limits DATE: 14/12/27 04:27:31 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 MITSuME and OISTER collaboration: We observed the field of GRB 141225A (D'Avanzo et al., GCNC 17229) 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 2014-12-26 18:53:27 UT (~19.9 h after the burst). We could not detect the previously reported afterglow (Gorosabel et al., GCNC 17230; Guidorzi et al., GCNC 17231) in all the three bands. Three sigma upper limits of the OT are listed below. We used SDSS-DR8 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 0.68285 15:24:25 3780.0 >19.7 >19.6 >19.0 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17245 SUBJECT: GRB 141225A: MASTER-SAAO OT light curve DATE: 14/12/28 12:16:57 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs D.Buckley, S. Potter, A. Kniazev, M. Kotze South African Astronomical Observatory E. Gorbovskoy,V. Lipunov, N.Tyurina, P.Balanutsa, D.Denisenko, M.Pruzhinskaya, A.Kuznetsov, V.Kornilov, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute O.Gres, K.Ivanov, S.Yazev, N.M.Budnev, V.A.Poleshchuk Irkutsk State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinsky, I.Zalozhnih, A. Popov Ural Federal University, Kourovka H. Levato and C. Saffe Instituto de Ciencias Astronomicas de la Tierra y del Espacio (ICATE), San Juan, Argentina C. Mallamacci, C. Lopez and F. Podest Observatorio Astronomico Felix Aguilar (OAFA), San Juan National University, Argentina MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru) installed several days ago in South African Astronomical Observatory (Sutherland) was automatically pointed to the Swift and Fermi GRB 141225A (Avanzo et. al. GCN 17229). Firstly MASTER-SAAO pointed by FERMI coordinates and made first exposure 28 sec after FERMI trigger at 2014-12-25 23:02:28 UT (Buckley et al., 17233). Then MASTER-SAAO pointed to the Swift coordinates 20 sec after Swift notice time and 113 sec after trigger time at 2014-12-25 23:03:00 UT. The results of our photometery are: Start T-T_mid Exp. Mag Coadd UT s s unf ? 23:03:00 123 20 17.1 no 23:03:34 161 30 17.3 no 23:04:15 207 40 17.5 no 23:05:05 263 50 17.7 no 23:06:06 329 60 18.9 no 23:07:17 405 70 18.7 no 23:08:38 556 200 19.0 2 23:12:19 823 290 19.8 2 23:17:31 3161 3600 21.3 20 Our band is well described by a parity 0.8R+0.2B (USNO B1). The light curve from 113 to 300 power low index is about alpha ~= 0.76+-0.10 (F ~ t_-alpha) and alpha =~ 1.51 from 400 to 1500 . We see ~1 magnitude depression at 329 sec. The magnitudes in the table are not corrected for the Galactic extinction because its less than the our errors (Schlegel et al. 1998). The light curve is available at http://master.sai.msu.ru/static/GRB/GRB141225A.png This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17248 SUBJECT: Christmas GRB 141225A: GROND Observations DATE: 14/12/29 16:59:03 GMT FROM: Alexander Kann at TLS Tautenburg D. A. Kann (TLS Tautenburg), P. Schady, and J. Greiner (both MPE Garching) report on behalf of the GROND team: We observed the field of GRB 141225A (Swift trigger 622476; D'Avanzo et al., GCN #17229) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile). Observations started at 05:58 UT on 26 December 2014, around 7 hours after the GRB trigger. They were performed at an average seeing of 1".4 and at an average airmass of 2.3. Based on images with exposure times of 2640 s in g'r'i'z' and 2400 s in JHK, we detect the afterglow (Gorosabel et al., GCN #17230, Guidorzi et al., GCN #17231) at the following AB magnitudes: g' = 22.56 +/- 0.07 mag, r' = 22.31 +/- 0.07 mag, i' = 22.34 +/- 0.14 mag, z' = 21.74 +/- 0.12 mag, J > 21.5 mag, H > 21.0 mag, and K > 17.3 mag. The colors do not point to a strongly extinguished afterglow, implying it is intrinsically faint. The given magnitudes and limits are derived based on calibrating the images against SDSS (g'r'i'z') and 2MASS field stars (JHK) and are not corrected for the Galactic foreground extinction corresponding to a reddening of E_(B-V)= 0.017 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17652 SUBJECT: GRB 141225A: GMG observation limit DATE: 15/03/29 09:33:06 GMT FROM: Jirong Mao at Yunnan Obs J. Mao, Y. X. Xin and J.-M. Bai (YNAO) report: We observed the field of GRB 141225A (D'Avanzo et al., GCN 17229) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatory. Observations began from UT 15:38:35.4 26th, Dec., 2014 (about 16.6 hours after the trigger). We did not detect the optical counterpart down to a limit of r'~24.3. J. Mao apologizes for this very later GCN circular submission.