//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22491 SUBJECT: GRB 180314B: Swift detection of a burst DATE: 18/03/14 22:37:00 GMT FROM: David Palmer at LANL P. D'Avanzo (INAF-OAB), A. Deich (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), B. Sbarufatti (PSU), M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 22:23:36 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 180314B (trigger=814305). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 297.866, +23.623 which is RA(J2000) = 19h 51m 28s Dec(J2000) = +23d 37' 24" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 50 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 22:25:03.9 UT, 87.0 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 297.88663, 23.62434 which is equivalent to: RA(J2000) = 19h 51m 32.79s Dec(J2000) = +23d 37' 27.6" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 68 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 consistent with the Galactic value of 8.94 x 10^21 cm^-2 (Willingale et al. 2013). The initial flux in the 2.5 s image was 6.44e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 94 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 none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the large, but uncertain, extinction expected. 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: 22492 SUBJECT: GRB 180314B: Prompt enhanced Swift-XRT position DATE: 18/03/14 23:20:59 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Using promptly downlinked XRT event data for GRB 180314B, we find an enhanced XRT position of the afterglow: RA, Dec: 297.8867, 23.6243 which is equivalent to: RA (J2000) = 19 51 32.82 Dec (J2000) = +23 37 27.4 with an uncertainty of 1.9 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/814305. Position enhancement is 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: 22494 SUBJECT: GRB 180314B: Enhanced Swift-XRT position DATE: 18/03/15 03:18:26 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 2454 s of XRT Photon Counting mode data and 2 UVOT images for GRB 180314B, 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 = 297.88665, +23.62406 which is equivalent to: RA (J2000): 19h 51m 32.80s Dec (J2000): +23d 37' 26.6" with an uncertainty of 1.5 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: 22495 SUBJECT: GRB 180314B: Swift-XRT refined Analysis DATE: 18/03/15 05:34:14 GMT FROM: Phil Evans at U of Leicester J.A. Kennea (PSU), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB), V. D'Elia (ASDC), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU) and P. D'Avanzo report on behalf of the Swift-XRT team: We have analysed 6.4 ks of XRT data for GRB 180314B (D'Avanzo et al. GCN Circ. 22491), from 102 s to 19.8 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 22492). The light curve can be modelled with an initial power-law decay with an index of alpha=0.08 (+0.09, -0.07), followed by a break at T+1503 s to an alpha of 1.42 (+/-0.08). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.55 (+0.21, -0.20). The best-fitting absorption column is 2.14 (+0.29, -0.27) x 10^22 cm^-2, in excess of the Galactic value of 8.9 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.8 x 10^-11 (1.9 x 10^-10) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.14 (+0.29, -0.27) x 10^22 cm^-2 Galactic foreground: 8.9 x 10^21 cm^-2 Excess significance: 7.6 sigma Photon index: 2.55 (+0.21, -0.20) If the light curve continues to decay with a power-law decay index of 1.42, the count rate at T+24 hours will be 5.5 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.7 x 10^-13 (1.1 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/00814305. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22496 SUBJECT: GRB 180314B: Swift/UVOT Upper Limits DATE: 18/03/15 16:38:44 GMT FROM: Samantha Oates at MSSL S. R. Oates (U.Warwick) 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 180314B 94 s after the BAT trigger (D'Avanzo et al., GCN Circ. 22491). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 22494) 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 94 244 147 >19.6 u_FC 308 558 246 >19.3 white 94 7249 666 >19.7 v 638 7660 607 >18.4 b 563 11580 471 >19.3 u 308 8274 834 >19.6 w1 687 8070 588 >19.5 m2 662 7865 607 >20.4 w2 614 7455 607 >20.5 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 2.21 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22497 SUBJECT: GRB 180314B: Zeiss-1000/CrAO optical upper limit DATE: 18/03/15 17:48:37 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Pozanenko (IKI), A. Novichonok (KIAM, PetrSU), I. Nikolenko (CrAO), A. Volnova (IKI), I. Molotov (KIAM) report on behalf of larger GRB follow-up collaboration: We observed the field of Swift GRB 180314B (D'Avanzo et al., GCN 22491) with Zeiss-1000/Koshka (CrAO) telescope starting March 15 (UT) 01:55:39. We obtained several images in R-filter. We do not detect any source within enhanced Swift-XRT position (Beardmore et al., GCN 22494). Preliminary photometry of the field is following. Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2018-03-15 01:55:39 0.15459 R 7*180 n/d n/d 22.2 The photometry is based on nearby USNO-B1.0 stars USNO-B1_id R1 1135-0426232 15.02 1135-0426125 15.64 1136-0433074 16.46 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22498 SUBJECT: GRB 180314B: Swift-BAT refined analysis DATE: 18/03/15 20:11:42 GMT FROM: Amy Lien at GSFC S. D. Barthelmy (GSFC), J. R. Cummings (CPI), P. D'Avanzo (INAF-OAB), H. A. Krimm (NSF/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-240 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180314B (trigger #814305) (D'Avanzo et al., GCN Circ. 22491). The BAT ground-calculated position is RA, Dec = 297.855, 23.634 deg which is RA(J2000) = 19h 51m 25.3s Dec(J2000) = +23d 38' 04.1" with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 66%. The mask-weighted light curve shows a multi-peaked structure that starts at ~ T-50 sec and ends at ~ T+35 s. The main peak occurs at ~ T0. T90 (15-350 keV) is 73.0 +- 9.4 sec (estimated error including systematics). The time-averaged spectrum from T-47.6 to T+34.4 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.41 +- 0.25. The fluence in the 15-150 keV band is 9.6 +- 1.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.57 sec in the 15-150 keV band is 1.1 +- 0.2 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/814305/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22499 SUBJECT: GRB 180314B: RATIR Optical Observations DATE: 18/03/15 23:01:36 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report: We observed the field of GRB 180314B (D'Avanzo et al., GCN 22491) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2018/03 15.46 to 2018/03 15.52 UTC (12.55 to 13.99 hours after the BAT trigger), obtaining a total of 1.07 hours exposure in the r and i bands. For a source within the Swift-XRT error circle, in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following 3-sigma upper limits: r > 23.29 i > 22.90 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.