Gamma-ray Burst 180718A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN NOTICE
  

  TITLE:           GCN/FERMI NOTICE
  NOTICE_DATE:     Wed 18 Jul 18 01:58:09 UT
  NOTICE_TYPE:     Fermi-GBM Flight Position
  RECORD_NUM:      48
  TRIGGER_NUM:     553571869
  GRB_RA:          329.967d {+21h 59m 52s} (J2000),
                   330.191d {+22h 00m 46s} (current),
                   329.361d {+21h 57m 27s} (1950)
  GRB_DEC:         +14.067d {+14d 04' 00"} (J2000),
                   +14.156d {+14d 09' 22"} (current),
                   +13.826d {+13d 49' 35"} (1950)
  GRB_ERROR:       27.78 [deg radius, statistical plus systematic]
  GRB_INTEN:       689 [cnts/sec]
  DATA_SIGNIF:     8.30 [sigma]
  INTEG_TIME:      0.064 [sec]
  GRB_DATE:        18317 TJD;   199 DOY;   18/07/18
  GRB_TIME:        7064.60 SOD {01:57:44.60} UT
  GRB_PHI:         186.00 [deg]
  GRB_THETA:        55.00 [deg]
  DATA_TIME_SCALE: 0.0640 [sec]
  HARD_RATIO:      0.50
  LOC_ALGORITHM:   3 (version number of)
  MOST_LIKELY:      88%  GRB
  2nd_MOST_LIKELY:   7%  Cyg X-1
  DETECTORS:       0,0,0, 0,0,0, 1,1,1, 1,1,1, 0,0,
  SUN_POSTN:       117.39d {+07h 49m 34s}  +21.05d {+21d 03' 03"}
  SUN_DIST:        132.28 [deg]   Sun_angle= 9.8 [hr] (West of Sun)
  MOON_POSTN:      185.17d {+12h 20m 41s}   +2.56d {+02d 33' 43"}
  MOON_DIST:       141.51 [deg]
  MOON_ILLUM:      32 [%]
  GAL_COORDS:       72.23,-31.44 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      337.45, 24.59 [deg] ecliptic lon,lat of the burst (or transient)
  LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180718082/quicklook/glg_lc_medres34_bn180718082.gif
  COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
  COMMENTS:        This trigger occurred at longitude,latitude = 23.68,9.12 [deg].  
  COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
  

• GCN Circular #22959
  D. Svinkin and K. Hurley, on behalf of the IPN,
  A. Y. Lien, D. Palmer, S. Barthelmy, J. Cummings, and H. Krimm, on behalf of the Swift-BAT team,
  A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team, and
  A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, report:
  The short-duration GRB 180718A was detected by Fermi (GBM; trigger 553571869), INTEGRAL (SPI-ACS), and Swift (BAT), at about 7065 s UT (01:57:45).
  We have triangulated this GRB to a GBM-INTEGRAL annulus centered at RA(2000)=260.736 deg (17h22m57s) Dec(2000)=+48.285 deg (+48d17'07"), whose radius is 79.182 +/- 2.067 deg (3 sigma).
  From the ground analysis using the available Swift/BAT event data from T-1 to T+2 sec, we found a 6.3 sigma detection in an image with intervals from T0-0.026 s to T0+0.165 s and energy range 15-150 keV, where T0 = 2018-07-18 01:57:44.530 UTC.
  The BAT ground-calculated position of this detection is RA, Dec = 336.019, 2.790 deg which is

      RA(J2000)  =  22h 24m 04.6s
      Dec(J2000) = +02d 47' 23.3"
  

  with an uncertainty of 3.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 25%. The position is consistent with the annulus.
  The BAT mask-weighted light curve shows a single-pulse structure that starts at ~T0 and ends at ~T+0.1 s. T90 (15-350 keV) is 0.08 +- 0.02 sec (estimated error including systematics).
  Due to the weakness of this burst, the BAT spectrum is not well-constrained. However, the burst seems to be relatively soft comparing to regular short GRBs.
  The results of the batgrbproduct analysis are available at https://gcn.gsfc.nasa.gov/notices_s/848489/BA/
  A ToO observation with Swift/XRT has been requested.
• GCN Circular #22960
  R. Hamburg (UAH), P. Veres (UAH), and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
  "At 01:57:44.60 UT on 18 July 2018, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 180718A (trigger 553571869 / 180718082), which was also detected by the INTEGRAL SPI-ACS and subsequently localized by IPN. Ground analysis of the Swift/BAT data revealed a detection consistent with the IPN annulus (GCN 22959).
  The angle from the Fermi LAT boresight at the GBM trigger time is 61 degrees.
  The GBM light curve consists of a single peak with a duration (T90) of about 0.08 s (50-300 keV). The time-averaged spectrum from T0-0.06 s to T0+0.02 s is adequately fit by a Band function with Epeak = 187 +/- 61 keV, alpha = -0.2 +/- 0.4, and beta = -2.3 +/- 0.5.
  The event fluence (10-1000 keV) in this time interval is (2.3 +/- 0.3)E-07 erg/cm^2. The 64-ms peak photon flux measured starting from T0-0.05 s in the 10-1000 keV band is 9 +/- 1 ph/s/cm^2.
  The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
• GCN Circular #22963
  P. A. Evans (U. Leicester) reports on behalf of the Swift team:
  Swift has initiated a ToO observation of the Swift/BAT GRB 180718A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/ToO_GRBs/00020802
  Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the Swift/BAT event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration.
  Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
  This circular is an official product of the Swift-XRT team.
• GCN Circular #22972
  D. Vlasenko, N.Tiurina, E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Kuznetsov, V.Chazov, I. Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov Lomonosov Moscow State University,SAI
  D. Buckley, South African Astronomical Observatory (SAAO)
  R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias (IAC)
  A. Tlatov, V.Senik, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
  R. Podesta, F. Podesta, C. Lopez, C.Francile Observatorio Astronomico Felix Aguilar (OAFA)
  H.Levato, Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
  O. Gres, N.M.Budnev , Yu.Ishmuhametova Irkutsk State University (ISU)
  A. Gabovich, V. Yurkov, Yu. Sergienko Blagoveschensk Educational State University (BSPU)
  MASTER Global Robotic Net ( Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) inspected GRB180718A (Svinkin et al. GCN22959 ; Fermi trigger 553571869 at 2018-07-18 01:57:44.60 UT , Hamburg et al. GCN22960; Swift BAT position RA,Dec2000= 22h 24m 04.6s +02d 47' 23.3" (Svinkin et al GCN22959; Evans et al. GCN22963)
  MASTER-Kislovodsk robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Pulkovo Solar Station) was pointed to the GRB180718A (D. Svinkin et al., GCN Circ #22959) 60867 sec after trigger time at 2018-07-18 18:52:12 UT . On our first (180s exposure) set we do not found optical transients within Swift error-box (ra=336.019 dec=2.790 r=0.05) brighter then 18.5.
  The observations made on zenit distance = 13.51 degrees, galaxy latitude b = -43.86 degree. The moon (39 % bright part) is 15 degrees above the horizon. The distance between moon and object is 142 The sun altitude is -17.5 degree. The errorbox observed 2 nights till 2018-07-19 22:23:00
  MASTER-Tavrida robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (SAI Crimea astronomical station) was pointed to the GRB180718A (D. Svinkin et al., GCN Circ #22959) 63704 sec after trigger time at 2018-07-18 19:39:29 UT . On our first (180s exposure) set we do not found optical transients within Swift error-box (ra=336.019 dec=2.790 r=0.05) brighter then 18.6.
  The observations made on zenit distance = 15.68 degrees, galaxy latitude b = -43.86 degree. The moon (39 % bright part) is 13 degrees above the horizon. The distance between moon and object is 142 The sun altitude is -18 degree. The errorbox observed 2 nights till 2018-07-19 21:25:48
  MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) was pointed to the GRB180718A (D. Svinkin et al., GCN Circ #22959) 161995 sec after trigger time at 2018-07-19 22:57:40 UT . On our first (180s exposure) set we do not found optical transients within Swift error-box (ra=336.019 dec=2.790 r=0.05) brighter then 17.5.
  The observations made on zenit distance = 18.52 degrees, galaxy latitude b = -43.86 degree. The moon (39 % bright part) is 25 degrees above the horizon. The distance between moon and object is 128 The sun altitude is -11.80 degree. The errorbox observed till 2018-07-19 23:53:58
  The visibility GRB error box (coord: 336.019 2.790 error_box: 0.05) at trigger time at different MASTER sites:

  obj:  43.32 sun: -3.21 - Tavrida (Crimea, Russia)
  obj:  53.60 sun: -39.34 - IAC, Teide, (Tenerife, Spain)
  obj:  53.56 sun: -45.24 - SAAO (Sutherland, SA)
  obj:  40.32 sun:  1.49 - Kislovodsk (Russia)
  obj:  23.50 sun:  16.36 -  Ural(Kourovka, Russia)
  obj:  0.76  sun:  41.53 -  Tunka (near Baykal Lake, Russia)
  obj: -14.45 sun:  55.06 -  Amur(Blagoveschensk)
  obj:  6.93  sun: -51.86 -   OAFA (Argentina)
  

  The message may be cited.
• GCN Circular #23030
  J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
  Swift-XRT has performed follow-up observations of the Swift/BAT-detected burst GRB 180718A (Svinkin et al. GCN Circ. 22959), collecting 1.5 ks of Photon Counting (PC) mode data between T0+113.7 ks and T0+115.2 ks.
  No X-ray sources have been detected consistent with being within 296 arcsec of the Swift/BAT position. The 3-sigma upper limit in the field ranges from ~0.005 to ~0.013 ct s^-1, corresponding to a 0.3-10 keV observed flux of 2.1e-13 to 5.1e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).
  The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at http://www.swift.ac.uk/ToO_GRBs/00020802.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #23216
  J. Bright (Oxford), K. P. Mooley (NRAO, Caltech; Jansky Fellow), R. P. Fender (Oxford)
  We observed the field of short GRB 180718A (Svinkin et al., GCN 22959) with the AMI Large Array at 15 GHz. Our observation on 2018 Jul 22.03 (UT) (3.95 d post-burst) does not reveal any potential afterglow candidate consistent with the BAT location (Svinkin et al., GCN 22959), and our 3sigma upper limit to the flux density is 180 uJy.
  We thank the MRAO staff for scheduling these observations. Results from the AMI Short GRB program are posted on the AMI-GRB database available at http://4pisky.org/ami-grb/.