GRB170318A

This page lists all entries on GRB170318A in GRBweb

Summary IPN Swift GCN 20904 GCN 20905 GCN 20907 GCN 20912 GCN 20914 GCN 20915 GCN 20917 GCN 20925 GCN 20956

Summary table
Variable Value Source
T0 12:11:56 UTC GCN_circulars,Swift Det
ra 305.6672° Swift
decl 28.4060° Swift
pos_error 2.20e-04° Swift
T90 133.7 s Swift
T90_start 12:11:56 UTC Swift
fluence 3.70e-06 erg/cm² Swift
T100 133.7 s
GBM_located False
mjd 57830.50828703704 GCN_circulars,Swift Det
IPN table
GRB_name GRB170318A
ra 305.6458°
decl 28.4167°
pos_error 5.00e-02°
Swift table
GRB_name GRB170318A
t_trigger 12:11:56 UTC
ra 305.6672°
decl 28.4060°
pos_error 2.20e-04°
T90 133.7 s
fluence 3.70e-06 erg/cm²
GCN 20904 table
GRB_name GRB170318A
GCN_number 20904
Detection_method Swift Det
t_trigger 12:11:56 UTC
ra 305.6450°
decl 28.4090°
Circular_text TITLE: GCN CIRCULAR NUMBER: 20904 SUBJECT: GRB 170318A: Swift detection of a burst DATE: 17/03/18 12:29:49 GMT FROM: David Palmer at LANL B. Sbarufatti (INAF-OAB/PSU), D. N. Burrows (PSU), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 12:11:56 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170318A (trigger=743065). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 305.645, +28.409 which is RA(J2000) = 20h 22m 35s Dec(J2000) = +28d 24' 32" 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 30 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 12:13:44.4 UT, 108.0 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 305.66565, 28.40652 which is equivalent to: RA(J2000) = 20h 22m 39.76s Dec(J2000) = +28d 24' 23.5" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 65 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 4.45 x 10^21 cm^-2 (Willingale et al. 2013). The initial flux in the 2.5 s image was 6.78e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 116 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 large, but uncertain extinction expected. Burst Advocate for this burst is B. Sbarufatti (boris.sbarufatti 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.)
GCN 20905 table
GRB_name GRB170318A
GCN_number 20905
Detection_method Swift-XRT Other
ra 305.6668°
decl 28.4066°
Circular_text TITLE: GCN CIRCULAR NUMBER: 20905 SUBJECT: GRB 170318A: Prompt enhanced Swift-XRT position DATE: 17/03/18 13:00:10 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 170318A, we find an enhanced XRT position of the afterglow: RA, Dec: 305.6668, 28.4066 which is equivalent to: RA (J2000) = 20 22 40.03 Dec (J2000) = +28 24 23.7 with an uncertainty of 2.1 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/743065. 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.
GCN 20907 table
GRB_name GRB170318A
GCN_number 20907
Detection_method Swift-XRT Det
ra 305.6673°
decl 28.4060°
Circular_text TITLE: GCN CIRCULAR NUMBER: 20907 SUBJECT: GRB 170318A: Enhanced Swift-XRT position DATE: 17/03/18 15:27:10 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 2006 s of XRT Photon Counting mode data and 1 UVOT images for GRB 170318A, 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 = 305.66732, +28.40600 which is equivalent to: RA (J2000): 20h 22m 40.16s Dec (J2000): +28d 24' 21.6" with an uncertainty of 1.9 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 20912 table
GRB_name GRB170318A
GCN_number 20912
Detection_method Swift-BAT Det
ra 305.6620°
decl 28.4080°
Circular_text TITLE: GCN CIRCULAR NUMBER: 20912 SUBJECT: GRB 170318A: Swift-BAT refined analysis DATE: 17/03/18 18:57:59 GMT FROM: Hans Krimm at NASA-GSFC/NSF J. R. Cummings (CPI),S. D. Barthelmy (GSFC), N. Gehrels (GSFC), H. A. Krimm (NSF/USRA),A. Y. Lien (GSFC/UMBC),C. B. Markwardt (GSFC), D. M. Palmer (LANL),T. Sakamoto (AGU),B. Sbarufatti (INAF-OAB/PSU), M. Stamatikos (OSU),T. N. Ukwatta (LANL)(i.e. the Swift-BAT team): Using the data set from T-239 to T+483 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170318A (trigger #743065) (Sbarufatti, et al., GCN Circ. 20904). The BAT ground-calculated position is RA, Dec = 305.662, 28.408 deg which is RA(J2000) = 20h 22m 38.9s Dec(J2000) = +28d 24' 30.5" with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 43%. The mask-weighted light curve shows a single FRED-shaped pulse that starts approximately T+20 sec, peaks at T+2 sec and decays to background by T+100 sec. T90 (15-350 keV) is 133.7 +- 42.8 sec (estimated error including systematics). The time-averaged spectrum from -21.544 to 175.788 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.35 +- 0.11. The fluence in the 15-150 keV band is 3.7 +- 0.3 x 10^-06erg/cm2. The 1-sec peak photon flux measured from T+1.87 sec in the 15-150 keV band is 1.2 +- 0.3 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/743065/BA/
GCN 20914 table
GRB_name GRB170318A
GCN_number 20914
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 20914 SUBJECT: GRB 170318A: Swift/UVOT Upper Limits DATE: 17/03/18 21:27:48 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 170318A 117 s after the BAT trigger (Sbarufatti et al., GCN Circ. 20904). No optical afterglow consistent with the XRT position (Evans et al. GCN Circ. 20907) 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 117 266 147 >20.4 u_FC 329 552 220 >19.6 white 117 6605 363 >20.8 v 2222 2241 19 >17.0 b 2147 6400 216 >19.8 u 329 6195 417 >20.1 w1 5790 5990 197 >19.4 m2 5585 5784 197 >19.3 w2 2197 11766 560 >20.4 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.97 in the direction of the burst (Schlegel et al. 1998).
GCN 20915 table
GRB_name GRB170318A
GCN_number 20915
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 20915 SUBJECT: GRB 170318A: RATIR Optical and NIR Observations DATE: 17/03/18 22:08:37 GMT FROM: Nat Butler at Az State U Nat Butler (ASU), Alan M. Watson (UNAM), 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 (ASU), and Vicki Toy (UMD) report: We observed the field of GRB 170318A (Sbarufatti, et al., GCN 20904) 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 2017/03 18.51 to 2017/03 18.53 UTC (3.0 to 27.6 minutes after the BAT trigger), obtaining a total of 0.24 hours exposure in the r and i bands and 0.11 hours exposure in the Z, Y, J, and H bands. We do not detect a source within the Swift-XRT error circle (Evans, et al., GCN 20907). In comparison with the USNO-B1 and 2MASS catalogs, we obtain the following upper limits (3-sigma): r > 23.39 i > 22.82 Z > 21.72 Y > 21.56 J > 21.12 H > 20.73 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We note that this field suffers large Galactic extinction (A_V~3). We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.
GCN 20917 table
GRB_name GRB170318A
GCN_number 20917
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 20917 SUBJECT: GRB 170318A: Swift-XRT refined Analysis DATE: 17/03/19 04:03:37 GMT FROM: Phil Evans at U of Leicester S. J. LaPorte (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU) and report on behalf of the Swift-XRT team: report on behalf of the Swift-XRT team: We have analysed 7.0 ks of XRT data for GRB 170318A, from 98 s to 41.1 ks after the BAT trigger. The data comprise 94 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The light curve can be modelled with an initial power-law decay with an index of alpha=1.09 (+0.51, -0.29), followed by a break at T+208 s to an alpha of 2.74 (+0.76, -0.17). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 0.84 (+0.20, -0.19). The best-fitting absorption column is 6.3 (+2.7, -1.9) x 10^21 cm^-2, consistent with the Galactic value of 4.4 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 0.92 (+0.35, -0.30) and a best-fitting absorption column of 6.4 (+4.6, -1.9) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 8.3 x 10^-11 (9.3 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 6.4 (+4.6, -1.9) x 10^21 cm^-2 Galactic foreground: 4.4 x 10^21 cm^-2 Excess significance: <1.6 sigma Photon index: 0.92 (+0.35, -0.30) If the light curve continues to decay with a power-law decay index of 2.74, the count rate at T+24 hours will be 4.0 x 10^-7 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.4 x 10^-17 (3.8 x 10^-17) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00743065. This circular is an official product of the Swift-XRT team.
GCN 20925 table
GRB_name GRB170318A
GCN_number 20925
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 20925 SUBJECT: GRB 170318A: KAIT Optical Upper Limit DATE: 17/03/20 19:32:13 GMT FROM: Max Genecov at UC Berkeley Max Genecov, WeiKang Zhang, and Alex Filippenko (UC Berkeley) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift GRB 170318A (Sbarufatti, et al., GCN 20904) starting at 12:33:14 UT, ~23 minutes after the burst. The target was at low elevation but rising. Observations were performed with an automatic sequence in the clear (roughly R) and I filters, and the exposure time was 20 s per image. We do not detect any optical source within the XRT error circle (Evans, et al., GCN 20907). The limiting magnitude of the co-added clear band image is ~17.6 at a mid-time of 39.7 minutes after the burst.
GCN 20956 table
GRB_name GRB170318A
GCN_number 20956
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 20956 SUBJECT: GRB 170318A: 15 GHz upper limits from AMI DATE: 17/03/31 13:30:46 GMT FROM: Kunal Mooley at Oxford U K. P. Mooley (Hintze Fellow, Oxford), T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester) The AMI Large Array robotically triggered on the Swift alert for GRB 170318A (Sbarufatti et al., GCN 20904) as part of the 4pisky program, and subsequent follow up observations were obtained up to 10 days post-burst. Our observations at 15 GHz on 2016 Mar 18.55 and Mar 21.50 (UT) do not reveal any radio source at the XRT location (Evans et al., GCN 20907), with 3sigma upper limits of 159 uJy and 93 uJy respectively. We thank the AMI staff for scheduling these observations. The AMI-GRB database is a log of all GRB follow up observations with the AMI, and is available at http://4pisky.org/ami-grb/.