//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17368 SUBJECT: GRB 150201A: Swift detection of a burst DATE: 15/02/01 14:00:16 GMT FROM: Hans Krimm at NASA-GSFC J. K. Cannizzo (NASA/UMBC), A. P. Beardmore (U Leicester), N. Gehrels (NASA/GSFC), H. A. Krimm (CRESST/GSFC/USRA), D. Malesani (DARK/NBI), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 13:46:59 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150201A (trigger=629302). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 11.832, -37.625 which is RA(J2000) = 00h 47m 20s Dec(J2000) = -37d 37' 29" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 20 sec. The peak count rate was ~21500 counts/sec (15-350 keV), at ~2 sec before the trigger. The XRT began observing the field at 13:48:26.8 UT, 87.2 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 11.8325, -37.6193 which is equivalent to: RA(J2000) = +00h 47m 19.80s Dec(J2000) = -37d 37' 09.5" with an uncertainty of 5.0 arcseconds (radius, 90% containment). This location is 20 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. The initial flux in the 2.5 s image was 3.03e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 92 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. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' 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 0.01. Burst Advocate for this burst is J. K. Cannizzo (cannizzo 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: 17369 SUBJECT: GRB 150201A: Enhanced Swift-XRT position DATE: 15/02/01 18:44:34 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 308 s of XRT Photon Counting mode data and 1 UVOT images for GRB 150201A, 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 = 11.83271, -37.61883 which is equivalent to: RA (J2000): 00h 47m 19.85s Dec (J2000): -37d 37' 07.8" 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: 17370 SUBJECT: GRB 150201A: Fermi GBM observation DATE: 15/02/02 02:08:31 GMT FROM: Veronique Pelassa at UAH H.-F. Yu (MPE) and V. Pelassa (UAH) report on behalf of the Fermi GBM Team: "At 13:46:55.15 UT on 01 Feb 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150201A (trigger 444491218 / 150201574), which was also detected by the Swift (Cannizzo et al. 2015, GCN 17368). The GBM on-ground location is consistent with the Swift position. The trigger resulted in an Autonomous Repoint Request (ARR) that was accepted and the spacecraft slewed to the GBM in-flight location. The angle from the Fermi LAT boresight is about 60 degrees. The GBM light curve shows a double-peaked pulse with a duration (T90) of about 16 s (50-300 keV). The time-averaged spectrum from T0-2.816 s to T0+36.097 s is well fit by a Band function with Epeak = 131 +/- 2 keV, alpha = -1.02 +/- 0.01, and beta = -2.70 +/- 0.06. The event fluence (10-1000 keV) in this time interval is (6.63 +/- 0.05)E-05 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+4.608 s in the 10-1000 keV band is 88.7 +/- 0.7 ph/s/cm^2. GBM triggered on GRB 150201590 23 minutes after GRB 150201A, at 14:09:56 UT (MET 444492598). The GBM localization of this 2nd trigger is RA, Dec = 2.1, -40.7 with an uncertainty of 2.7 deg (radius, 1-sigma containment,statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This is consistent with the position of GRB 150201A. As seen by GBM, this second event shows a multi-peaked pulse with a duration (T90) of about 26 s (50-300 keV). The time-averaged spectrum from T0-0.512 s to T0+22.016 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -0.61 +/- 0.15 and the cutoff energy, parameterized as Epeak, is 105 +/- 8 keV. The event fluence (10-1000 keV) in this time interval is (2.13 +/- 0.11)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+7.104 s in the 10-1000 keV band is 2.1 +/- 0.2 ph/s/cm^2. At the time of this 2nd trigger the position of 150201A was occulted by the Earth to the Swift spacecraft. The GBM data suggest the two events may have a common origin. Because of the uncertainty in the GBM localization, we cannot exclude the possibility that this is a chance coincidence and that GRB 150201590 is unrelated to GRB 150201A. Owing to the possible relationship between the two triggers, which would make this an unusually long GRB, Fermi is observing the position of GRB 150201A as a target of opportunity for a period of 24 hours, subject to Earth limb constraints. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17371 SUBJECT: GRB 150201A: Swift-XRT refined Analysis DATE: 15/02/02 09:00:05 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), B.P. Gompertz (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), M. de Pasquale (INAF-IASFPA), M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU) and J.K. Cannizzo report on behalf of the Swift-XRT team: We have analysed 7.9 ks of XRT data for GRB 150201A (Cannizzo et al. GCN Circ. 17368), from 75 s to 51.9 ks after the BAT trigger. The data comprise 823 s in Windowed Timing (WT) mode (the first 7 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 17369). The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=1.12 (+0.15, -0.13). At T+161 s the decay flattens to an alpha of 0.62 (+0.03, -0.04) before breaking again at T+833 s to a final decay with index alpha=1.256 (+0.032, -0.026). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.86 (+/-0.04). The best-fitting absorption column is 3.82 (+0.21, -0.20) x 10^21 cm^-2, in excess of the Galactic value of 5.8 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.30 (+0.17, -0.16) and a best-fitting absorption column of 4.7 (+0.8, -0.7) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (6.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 4.7 (+0.8, -0.7) x 10^21 cm^-2 Galactic foreground: 5.8 x 10^20 cm^-2 Excess significance: 9.3 sigma Photon index: 2.30 (+0.17, -0.16) If the light curve continues to decay with a power-law decay index of 1.256, the count rate at T+24 hours will be 0.037 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x 10^-12 (2.4 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00629302. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17372 SUBJECT: GRB 150201A: GROND upper limits DATE: 15/02/02 14:54:42 GMT FROM: Fabian Knust at MPE/GROND F. Knust, T. Schweyer, J. Bolmer, J. Greiner (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 150201A (Swift trigger 629302; J. K. Cannizzo et al., GCN #17368) 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 00:47 UT on 2015-02-02, 11hrs after the GRB trigger. They were performed at an average seeing of 1.64" and at an average airmass of 2.1. We do not detect a source within the Swift-XRT error circle reported by J.P. Osborne et al. (GCN #17369) down to g' > 23.2 mag, r' > 23.1 mag, i' > 23.5 mag, z' > 23.6 mag, J > 21.5 mag, H > 21.0 mag, and K > 19.4 mag. The given limits are derived based on calibrating the images against GROND zeropoints and 2MASS field stars and are not corrected for the Galactic foreground extinction corresponding to a reddening of E_(B-V)= 0.012 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17373 SUBJECT: Konus-Wind observation of GRB 150201A DATE: 15/02/02 17:10:25 GMT FROM: Anastasia Tsvetkova at Ioffe Institute S. Golenetskii, R. Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The long-duration, intense GRB 150201A (Swift BAT trigger 629302: Cannizzo et al., GCN 17368; Fermi-GBM detection: Yu and Pelassa, GCN 17370) triggered Konus-Wind at T0=49611.653 s UT (13:46:51.653). The burst light curve shows a double-peaked pulse with a total duration of ~26 s. The emission is seen up to ~10 MeV. No post-burst activity was observed by Konus-Wind until ~T0+450s; also, since the instrument switched to the read-out mode, there are no triggered or waiting mode data available for the time of the second GBM trigger 150201590 (14:09:56 UT; GCN 17370). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB150201_T49611/ As observed by Konus-Wind, the burst had a fluence of 6.18(-0.22,+0.23)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+1.712 s, of 2.10(-0.28,+0.30)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+22.272 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -1.20(-0.11,+0.13), the high energy photon index beta = -2.89(-0.27,+0.17), the peak energy 123(-6,+5) keV (chi2 = 88/93 dof) The spectrum near the maximum count rate (measured from T0 to T0+2.048 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.77(-0.12,+0.14), the high energy photon index beta = -2.47(-0.25,+0.17), the peak energy 193(-20,+21) keV (chi2 = 65/50 dof) All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17374 SUBJECT: GRB 150201A, Swift-BAT refined analysis DATE: 15/02/02 18:23:30 GMT FROM: Hans Krimm at NASA-GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. K. Cannizzo (NASA/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150201A (trigger #629302) (Cannizzo, et al., GCN Circ. 17368). The BAT ground-calculated position is RA, Dec = 11.820 -37.620 deg which is RA(J2000) = 00h 47m 16.8s Dec(J2000) = -37d 37' 10" with an uncertainty of 1.7 arcmin,(radius, sys+stat, 90% containment). It is 0.6 arcmin from the XRT enhanced position. The partial coding was 3%. The burst was outside the BAT calibrated field of view. It came into the field during the slew to point the narrow-field instruments. The earliest calibrated event data starts at about T+22 s. The non-weighted light curve shows two main peaks at about T-3 and T+1 seconds. The emission is detectable out to approximately T+50 sec. T90 (15-350 keV) is 26.1 +- 5.2 sec (estimated error including systematics). The time-averaged spectrum from T+22.2 to T+49.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.32 +- 0.24. The fluence in the 15-150 keV band is 7.8 +- 1.2 x 10^-07 erg/cm2. This calibrated fluence is on the order of 5% of the total fluence. 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/629302/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17375 SUBJECT: GRB 150201A: Swift/UVOT Upper Limits DATE: 15/02/02 19:29:53 GMT FROM: Frank Marshall at GSFC F. E. Marshall (NASA/GSFC) and J. K. Cannizzo (CRESST/GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 150201A 93 s after the BAT trigger (Cannizzo et al., GCN Circ. 17368). No optical afterglow consistent with the XRT position (Osborne et al. GCN Circ. 17369) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 93 243 147 >21.0 u_FC 306 556 246 >20.4 white 93 913 239 >21.5 v 635 829 39 >18.6 b 561 755 35 >19.8 u 306 729 265 >20.3 w1 685 705 19 >19.6 w2 784 804 19 >19.6 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).