Gamma-ray Burst 190122A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #23767
  F. Longo (University and INFN Trieste), E. Bissaldi (Politecnico & INFN Bari), M. Axelsson (KTH & Stockholm Univ.), M. Arimoto (Kanazawa Univ.), F. Piron (CNRS/IN2P3/LUPM) and N. Omodei (Stanford Univ.) report on behalf of the Fermi-LAT team:
  On January, 22, 2019, Fermi-LAT detected high-energy emission from GRB 190122A, which was also detected by the Fermi GBM (trigger 569834352 / 190122305).
  The best LAT on-ground location is found to be
  RA, Dec = 258.71, 48.12 (degrees, J2000)
  with an error radius of 0.91 deg (90% containment, statistical error only).
  The LAT position was 26 deg from the LAT boresight at the time of the GBM trigger time (07:19:07.57 UT) and remained in the LAT field of view for ~1000 seconds, and then re-entered the FoV ~3800s after the trigger.
  The data from the Fermi-LAT show a significant increase in the event rate above 100 MeV during the interval 0 4000s that is spatially correlated with the GBM trigger. The spectrum of the GRB appears to be soft, and the highest-energy photon is a 310 MeV event, which is observed ~820 seconds after the GBM trigger.
  GRB190122A is also detected with high significance in the LAT Low Energy events (LLE), with a time profile which is temporally coincident with the GBM light curve.
  Further analysis will be performed as more data become available.
  The Fermi-LAT point of contact for this burst is Francesco Longo (francesco.longo@ts.infn.it).
  The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
• GCN Circular #23768
  E. Bissaldi (Politecnico & INFN Bari), C. Meegan (UAH) and P. Veres (UAH) report on behalf of the Fermi GBM Team:
  "At 07:19:07.57 UT on 22 January 2019, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 190122A (trigger 569834352 / 190122305), which was also detected by the Fermi/LAT (Longo et al. 2019, GCN 23767). The GBM on-ground location is consistent with the LAT position.
  The angle from the Fermi LAT boresight at the GBM trigger time is 26 degrees.
  The GBM light curve consists of a single FRED-like pulse with a duration (T90) of about 54 s (50-300 keV). The time-averaged spectrum from T0+0.8 s to T0+22.3 s is adequately fit by a simple power law function with index -1.59 +/- 0.01.
  The event fluence (10-1000 keV) in this time interval is (3.95 +/- 0.10)E-7 erg/cm^2. The 1-sec peak photon flux measured starting from T0+5.6 s in the 10-1000 keV band is 6.3 +/- 0.3 ph/s/cm^2.
  The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
• GCN Circular #23783
  D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, report:
  The long-duration GRB 190122A (Fermi-LAT detection: Longo et al., GCN Circ. 23767; Fermi-GBM detection: Bissaldi et al., GCN Circ. 23768) triggered Konus-Wind at T0=26347.426 s UT (07:19:07.426).
  The burst light curve shows a FRED-like pulse which starts at ~T0-0.4 s and has a total duration of ~67 s. The emission is seen up to ~6 MeV.
  As observed by Konus-Wind, the burst had a fluence of 3.52(-0.74,+0.85)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0-0.046 s, of 3.77(-1.47,+3.90)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  The time-averaged spectrum of the burst (measured from T0 to T0+73.984 s) is best fit in the 20 keV - 15 MeV range by a simple power-law function with the photon index = -1.58(-0.08,+0.08), chi2 = 80/99 dof. Fitting by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -1.48(-0.12,+0.16) and only an upper limit on Ep: Ep > 560 keV (chi2 = 76/98 dof).
  The spectrum near the maximum count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by a power law with exponential cutoff model: with alpha = -1.43(-0.16,+0.17) and Ep = 718(-337,+7104) keV (chi2 = 99/98 dof).
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB190122_T26347/
  All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.