Gamma-ray Burst 220927A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN NOTICE
  

  TITLE:           GCN/FERMI NOTICE
  NOTICE_DATE:     Tue 27 Sep 22 10:29:28 UT
  NOTICE_TYPE:     Fermi-GBM Final Position
  RECORD_NUM:      0
  TRIGGER_NUM:     685949785
  GRB_RA:           96.910d {+06h 27m 38s} (J2000),
                    97.136d {+06h 28m 33s} (current),
                    96.413d {+06h 25m 39s} (1950)
  GRB_DEC:         -27.490d {-27d 29' 23"} (J2000),
                   -27.505d {-27d 30' 18"} (current),
                   -27.458d {-27d 27' 26"} (1950)
  GRB_ERROR:       1.14 [deg radius, statistical only]
  GRB_DATE:        19849 TJD;   270 DOY;   22/09/27
  GRB_TIME:        20180.95 SOD {05:36:20.95} UT
  GRB_PHI:          97.31 [deg]
  GRB_THETA:        52.05 [deg]
  E_RANGE:         10.000 - 50.000 [keV]
  LOC_ALGORITHM:   415 (Gnd S/W Version number)
  SUN_POSTN:       183.95d {+12h 15m 48s}   -1.71d {-01d 42' 37"}
  SUN_DIST:         86.39 [deg]   Sun_angle= 5.8 [hr] (West of Sun)
  MOON_POSTN:      201.95d {+13h 27m 48s}   -7.11d {-07d 06' 45"}
  MOON_DIST:        99.66 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:      235.62,-17.00 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:       99.70,-50.70 [deg] ecliptic lon,lat of the burst (or transient)
  LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220927234/quicklook/glg_lc_medres34_bn220927234.gif
  LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220927234/quicklook/glg_locplot_all_bn220927234.png
  COMMENTS:        Fermi-GBM Final Position.  
  COMMENTS:        This Notice was ground-generated -- not flight-generated.  
  COMMENTS:        The LC_URL file should be available by the time this FINAL notice is produced.  
  COMMENTS:        This notice has human-in-the-loop processing.  
  COMMENTS:           
  COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the KONUS event (trignum=1984920180).  
  

• GCN Circular #32594
  The Fermi GBM team reports the detection of a likely Long GRB.
  "At 05:36:20.95 UT on 27 September 2022, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB220927A (trigger 685949785 / 220927234).
  The on-ground calculated location, using the GBM trigger data, is RA = 96.2, DEC = -22.5 (J2000 degrees, equivalent to 6h 24m, -22d 30'), with a statistical uncertainty of 1 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which we have characterized as a core-plus-tail model, with 90% of GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).
  The angle from the Fermi LAT boresight at the GBM trigger time is 57 degrees.
  The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220927234/quicklook/glg_skymap_all_bn220927234.png
  The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220927234/quicklook/glg_healpix_all_bn220927234.fit
  The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220927234/quicklook/glg_lc_medres34_bn220927234.gif
  
• GCN Circular #32597
  A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars-Odyssey team,
  A. Ridnaia, D. Frederiks, D. Svinkin, A. Lysenko, and T. Cline on behalf of the Konus-Wind team,
  A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team,
  E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
  S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT team,
  and
  W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report:
  The long-duration GRB 220927A (Fermi-GBM detection: Fermi GBM Team, GCN 32594) has been detected by Fermi (GBM trigger 685949785), INTEGRAL (SPI-ACS), Konus-Wind, Mars-Odyssey (HEND), and Swift (BAT), so far, at about 20180 s UT (05:36:20). 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:
     90.969 (06h 03m 52s) -22.946 (-22d 56' 45")
   Corners:
     88.336 (05h 53m 21s) -23.483 (-23d 28' 59")
     88.391 (05h 53m 34s) -23.818 (-23d 49' 04")
     93.560 (06h 14m 14s) -22.267 (-22d 16' 00")
     93.494 (06h 13m 59s) -21.929 (-21d 55' 45")
   ---------------------------------------------
  

  The error box area is 1.68 sq. deg, and its maximum dimension is 5.1 deg (the minimum one is 20 arcmin). The Sun distance was 90 deg.
  This box may be improved.
  The IPN localization is consistent with, but reduces the area of, the Fermi-GBM final localization (GCN 32594).
  A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB220927_T20180/IPN
  The time history and spectrum will be given in forthcoming GCN Circulars.
  
• GCN Circular #32598
  V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (Lomonosov Moscow State University, SAI, Physics Department),
  R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),
  R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
  D. Buckley (South African Astronomical Observatory),
  O.A. Gres, N.M. Budnev (Irkutsk State University, API),
  L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory),
  A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
  A. Gabovich, V.Yurkov (Blagoveschensk Educational State University)
  MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 220927A ( Fermi GBM team, GCN 32594) errorbox 43499 sec after notice time and 61090 sec after trigger time at 2022-09-27 22:34:31 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 74 deg. The sun altitude is -56.2 deg.
  The galactic latitude b = -17 deg., longitude l = 236 deg.
  Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2102352
  We obtain a following upper limits.

  Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
  _________|_____________________|_____________________|____________________________________|_____|_______|_______|________
  
  
     61121 | 2022-09-27 22:34:31 |         MASTER-SAAO | (06h 17m 38.05s , -29d 19m 22.8s) |   C |    60 | 17.4 |        
     61203 | 2022-09-27 22:35:54 |         MASTER-SAAO | (06h 26m 53.28s , -29d 18m 55.6s) |   C |    60 | 17.1 |        
  

  Filter C is a clear (unfiltred) band.
  The observation and reduction will continue. The message may be cited.
• GCN Circular #32600
  A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
  The long-duration GRB 220927A (Fermi-GBM detection: Fermi GBM Team, GCN 32594; IPN triangulation: Kozyrev et al., GCN 32597) triggered Konus-Wind at T0=20180.364 s UT (05:36:20.364).
  The burst light curve shows a multipeaked initial emission episode which starts at ~T0-1.9 s and ends at ~T0+8.3 s, followed by a weaker episode at ~T0+35 s. The total burst duration is ~46.7 s. The emission is seen up to 2 MeV.
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB220927_T20180/
  As observed by Konus-Wind, the burst had a fluence of 4.18(-1.08,+1.60)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0+3.968 s, of 9.37(-2.57,+2.78)x10^-7 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  The time-integrated spectrum of the burst (measured from T0 to T0+41.216 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 = -1.37(-0.77,+2.06), the high energy photon index beta = -2.60(-7.40,+0.35), the peak energy Ep = 40(-22,+15) keV, chi2 = 93/96 dof.
  The spectrum near the maximum count rate (measured from T0 to T0+8.448 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 = -0.97(-0.43,+0.61), the high energy photon index beta = -3.04(-6.96,+0.44), the peak energy Ep = 48(-6,+6) keV, chi2 = 83/94 dof.
  All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
• GCN Circular #32622
  A. Pal (Konkoly Observatory), J. Ripa, N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), M. Dafcikova, N. Husarikova, J.-P. Breuer, F. Munz , M. Topinka, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
  The long-duration GRB 220927A (Fermi-GBM detection: Fermi GBM Team, GCN 32594; IPN triangulation: Kozyrev et al., GCN 32597; Konus-Wind detection: Ridnaia et al. GCN 32600) was detected by the GRBAlpha 1U CubeSat (Pal et al. Proc. SPIE 2020).
  The 19.7 sigma detection was confirmed at the peak time 2022-09-27 05:36:25.2 UTC. The GRB has the T90 duration of 8 s.
  The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB220927A_GCN.pdf
  GRBAlpha is a demonstration mission for a future CubeSats constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from about 50 keV to about 1000 keV. GRBAlpha was launched on 2021 March 22 from Baikonur. After its commissioning phase, the scientific observations are now under way. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.