Gamma-ray Burst 180626C

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN NOTICE
  

  TITLE:           GCN/FERMI NOTICE
  NOTICE_DATE:     Tue 26 Jun 18 09:24:14 UT
  NOTICE_TYPE:     Fermi-GBM Flight Position
  RECORD_NUM:      46
  TRIGGER_NUM:     551697835
  GRB_RA:          221.467d {+14h 45m 52s} (J2000),
                   221.545d {+14h 46m 11s} (current),
                   221.256d {+14h 45m 01s} (1950)
  GRB_DEC:         +66.700d {+66d 42' 00"} (J2000),
                   +66.623d {+66d 37' 23"} (current),
                   +66.909d {+66d 54' 32"} (1950)
  GRB_ERROR:       10.67 [deg radius, statistical plus systematic]
  GRB_INTEN:       803 [cnts/sec]
  DATA_SIGNIF:     7.10 [sigma]
  INTEG_TIME:      0.064 [sec]
  GRB_DATE:        18295 TJD;   177 DOY;   18/06/26
  GRB_TIME:        33830.65 SOD {09:23:50.65} UT
  GRB_PHI:         110.00 [deg]
  GRB_THETA:       150.00 [deg]
  DATA_TIME_SCALE: 0.0640 [sec]
  HARD_RATIO:      0.16
  LOC_ALGORITHM:   3 (version number of)
  MOST_LIKELY:      96%  GRB
  2nd_MOST_LIKELY:   2%  Cyg X-1
  DETECTORS:       0,0,0, 0,0,0, 0,1,0, 1,1,0, 0,0,
  SUN_POSTN:        95.17d {+06h 20m 41s}  +23.35d {+23d 21' 04"}
  SUN_DIST:         81.50 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
  MOON_POSTN:      253.79d {+16h 55m 09s}  -18.53d {-18d 31' 47"}
  MOON_DIST:        88.48 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      106.90, 46.71 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      157.13, 71.23 [deg] ecliptic lon,lat of the burst (or transient)
  LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180626392/quicklook/glg_lc_medres34_bn180626392.gif
  COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
  COMMENTS:        This trigger occurred at longitude,latitude = 274.73,-3.08 [deg].  
  COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
  

• GCN Circular #22864
  D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova, and T. Cline on behalf of the Konus-Wind team,
  K. Hurley, on behalf of the IPN,
  A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team,
  A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
  and
  S. Barthelmy, J. Cummings, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, report:
  The short-duration GRB 180626C was detected by Fermi (GBM; trigger 551697835), INTEGRAL (SPI-ACS), Konus-Wind, and Swift (BAT), at about 33831 s UT (09:23:51). The burst was outside the coded field of view of the BAT.
  We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:

    ---------------------------------------------
     RA(2000), deg                 Dec(2000), deg
    ---------------------------------------------
    Center:
     278.579 (18h 34m 19s) +47.241 (+47d 14' 28")
    Corners:
     290.010 (19h 20m 02s) +48.528 (+48d 31' 40")
     290.186 (19h 20m 45s) +48.912 (+48d 54' 42")
     265.423 (17h 41m 42s) +43.214 (+43d 12' 49")
     264.736 (17h 38m 57s) +42.455 (+42d 27' 17")
    ---------------------------------------------
  

  The error box area is 6.85 sq. deg, and its maximum dimension is 18.81 deg (the minimum one is 22 arcmin). The Sun distance was 106 deg.
  This box may be improved.
  A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB180626_T33832/IPN
  The localization of this burst is inconsistent with that of the short burst GRB 180626B, reported in GCN Circ. 22863.
  The time history and spectrum will be given in forthcoming GCN Circulars.
• GCN Circular #22868
  A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report:
  The short-duration GRB 180626C (IPN triangulation: Svinkin et al., GCN 22864) triggered Konus-Wind at T0=33832.424 s UT (09:23:52.424).
  The burst light curve shows a single pulse which starts at T0-40 ms and has a total duration of ~340 ms.
  As observed by Konus-Wind, the burst had a fluence of 6.13(-1.15,+2.18)x10^-7 erg/cm2, and a 16-ms peak flux, measured from T0-0.032 s, of 7.87(-2.06,+3.15)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  Since the most intense part of the burst was detected before the trigger, the spectral analysis was performed using the KW 3-channel light curve data.
  Modeling the KW 3-channel time-integrated spectrum (from T0-0.04 s to T0+0.336 s) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -0.87 (-0.23,+0.31), and Ep = 406 (-113,+225) keV.
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB180626_T33832/
  All the quoted errors are at the 68% confidence level. All the quoted values are preliminary.
• GCN Circular #22871
  FROM: Michael Coughlin at Caltech/LIGO
  Michael W. Coughlin (Caltech), Leo P. Singer (NASA GSFC), Tom=E1s Ahumada (UMD), S. Bradley Cenko (NASA GSFC), Shaon Ghosh (UWM), Mansi M. Kasliwal (Caltech), Eric C. Bellm (UW), V. Zach Golkhou (UW), Ludwig Rauch (DESY), Robert Stein (DESY), on behalf of the ZTF and GROWTH collaborations and the KPED team
  We observed the localization region of the short GRB 180626 (trigger 551697835) detected by the Gamma-Ray Burst Monitor (GBM) on the Fermi satellite with the Palomar 48 inch telescope equipped with the 47 square degree Zwicky Transient Facility (ZTF) camera. We obtained a series of r- and g-band images covering 275 square degrees beginning at 10:52 UT on 2018 June 26 (1:29 hours after the burst trigger time), corresponding to ~ 36% of the probability enclosed in the localization region. Using the IPN updated localization of GRB 180626 available the next day, we observed the new region with ZTF beginning at 05:01 UT on 2018 June 27 (19:43 hours after the trigger time). The observations covered 230 square degrees, corresponding to ~ 87% of the probability enclosed in the localization region.
  The images were processed through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts. 45 high-significance transient and variable candidates were identified by our pipeline in the area observed, all of which had previous detections with ZTF in the days and weeks prior to the GRB trigger time (e.g., supernovae, active galactic nuclei). Out of the 45 transients, only 1 transient was within the IPN localization region, but the object has previous detections at similar magnitudes. No viable optical counterparts were thus identified.
  We would like to highlight one interesting object discovered in the ZTF fields on the first night (it does not fall into the IPN localization region) and later followed up with the Kitt Peak EMCCD Demonstrator (KPED) on the Kitt Peak 84 inch telescope on June 27. Located at RA: 19:48:49.1 , DEC: +46:30:36.1, ZTF18aauebur was first detected by ZTF June 25.30 (1 day before the trigger); it is a rapidly evolving transient that has gone from g =3D 18.4 to g =3D 20.5 in 1.92 days. An underlying source is present at this location in Pan-STARRS DR1 and GALEX. Given the low Galactic latitude, it may be a stellar flare.
  The median 5 sigma upper limit for an isolated point source in our images was r > 20.9 and g > 20.9 mag for the observations made on June 26 and r > 21.2 and g > 21.0 mag for the observations made on June 27.
  ZTF is a project led by PI S. R. Kulkarni at Caltech (see ATEL #11266 <http://www.astronomerstelegram. org/?read=11266), and includes IPAC; WIS, Israel; OKC, Sweden; JSI/UMd, USA; UW, USA; DESY, Germany; NRC, Taiwan; UW Milwaukee, USA and LANL USA. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. Alert distribution service provided by DIRAC@UW. Alert filtering is being undertaken by the GROWTH marshal system, supported by NSF PIRE grant 1545949.
• GCN Circular #22874
  V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tiurina, A.Kuznetsov, V.Chazov, I. Gorbunov, D. Vlasenko, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov Lomonosov Moscow State University,SAI
  R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias
  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)
  D. Buckley South African Astronomical Observatory
  O. Gres, N.M.Budnev , Yu.Ishmuhametova Irkutsk State University
  A. Gabovich, V. Yurkov, Yu. Sergienko Blagoveschensk Educational State University, Blagoveschensk
  MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) , located in Teyde Observatory (IAC, Spain), was pointed to the IPN (Svinkin et al. GCN22864, Kozlova et al. GCN22868) Triangulation GRB180626C / Fermi trigger 551697835 (GRB_Time 18/06/26 09:23:50.65UT; RA,Dec(2000)=19h 00m 14s +44d 49' 12" (GRB_ERROR: 8.21 deg radius, statistical only , see https://gcn.gsfc.nasa.gov/other/551697835.fermi) also inspected by ZTF (Coughlin et al. GCN22871) at 2018-06-26 21:37:30UT-22:53:48 with unfiltered mlim=19.1 (180s expositions); 2018-06-27 03:34:57-03:53:20 with mlim=19.7 on summary expositions (5sigma, exp=540s). The observations started on zenit distance = 41 degrees. The sun altitude was -17.66 degree.
  MASTER-SAAO robotic telescope located in South Africa started Fermi inspection 5834 sec after notice time and 37433 sec after trigger time at 2018-06-26 19:51:28 UT. The 5-sigma upper limit on our second (180s exposure) set is about 16.2mag. The observations started on zenit distance = 89 degrees, galaxy latitude b = 22 degree. The moon (98 % bright part) is 64 degrees above the horizon. The distance between moon and object is 69. The sun altitude was -52.2 degree.
  MASTER-Amur robotic telescope, located at BSPU, was pointed to Fermi trigger 551697835 on 2018-06-27 14:09:39UT, and observed till 14:57:32.584UT with mlim=18.0(180s exp)
  MASTER-Kislovodsk robotic telescope, located at Kislovodsk Solar Station of Pulkovo observatory, started Fermi trigger inspection at 2018-06-27 20:53:26 UT. The 5-sigma upper limit on our first (180s exposure) set is about 18.8mag . The observations started on zenit distance = 6 degrees, galaxy latitude b = 22 degree. The moon (100 % bright part) is 26 degrees above the horizon. The distance between moon and object is 68 .The sun altitude is -22.8 degree.
  New OT, that could be connected with GRB, wasn't found.
• GCN Circular #22879
  J.Lyman, D.Steeghs, K.Ulaczyk, A.Levan, B.Gompertz (U. Warwick), N.Tanvir (U. Leicester), M.Dyer (U. Sheffield), K. Ackley, D.Galloway, E.Rol (Monash U.), G.Ramsay (Armagh O.), V.Dhillon (U. Sheffield), P.O'Brien (U. Leicester), S.Poshyachinda (NARIT), D.Pollacco (U. Warwick), E.Thrane (Monash U.)
  report on behalf of the GOTO collaboration:
  In response to the short-duration GRB 180626C (GCN 22864, 22868, 22871, 22874), the Gravitational-wave Optical Transient Observer (GOTO) observed the IPN triangulation region as reported in Svinkin et al. (GCN 22864).
  Observations were spread over several telescope array pointings, beginning 2018-06-26T22:21 UT (13 hours after the burst) and employ sets of 3x120s exposures in our wide L filter(400-700nm). Approximately 95% of the IPN region was covered on-chip. These fields were repeated in subsequent nights to permit difference imaging analysis and typically achieved a 5 sigma limiting magnitude of V=20.1-20.3 (based on zeropoints derived from APASS crossmatching).
  We made use of the GLADE galaxy catalog to pay particular attention to possible source candidates near galaxies within 200 Mpc. Similar to the searches reported in Coughlin et al. (GCN 22871) and Lupinov et al. (GCN 22874), we find no significant sources that could be credibly associated with the GRB.
  GOTO is operated at the La Palma observing facilities of the University of Warwick on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT) and the Instituto de Astrofisica de Canarias (IAC)
  https://goto-observatory.org/