Gamma-ray Burst 230623A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #34068
  Y. Hagiwara (Miyazaki U.), H. Negoro, M. Nakajima (Nihon U.), M. Serino (AGU), K. Kobayashi, M. Tanaka, Y. Soejima, Y. Kudo (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU), Y. Tsuboi, S. Urabe, S. Nawa, N. Nemoto (Chuo U.), M. Shidatsu (Ehime U.), I. Takahashi, M. Niwano, S. Sato, N. Higuchi, Y. Yatsu (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, T. Kurihara (JAXA), Y. Ueda, K. Setoguchi, T. Yoshitake, Y. Nakatani (Kyoto U.), M. Yamauchi, Y. Umeki, Y. Otsuki (Miyazaki U.), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC), W. Iwakiri (Chiba U.) report on behalf of the MAXI team:
  The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 07:23:37 UT on 23 June 2023. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (349.981 deg, -17.842 deg) = (23 19 55, -17 50 31) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.23 deg and 0.2 deg, respectively. The roll angle of long axis from the north direction is 40.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 185 +- 29 mCrab (4.0-10.0keV, 1 sigma error). Without assumptions on the source constancy, we obtain a rectangular error box for the transient source with the following corners:

  (R.A., Dec) = (349.422, -18.340) deg = (23 17 41, -18 20 23) (J2000)
  (R.A., Dec) = (349.773, -18.563) deg = (23 19 05, -18 33 46) (J2000)
  (R.A., Dec) = (350.604, -17.375) deg = (23 22 24, -17 22 30) (J2000)
  (R.A., Dec) = (350.255, -17.153) deg = (23 21 01, -17 09 10) (J2000)
  

  There was no significant excess flux in the previous transit at 05:50 UT and in the next transit at 08:56 UT with an upper limit of 20 mCrab for each.
• GCN Circular #34071
  P. A. Evans (U. Leicester) reports on behalf of the Swift team:
  Swift has initiated a series of observations, tiled on the sky, of the MAXI GRB 230623A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00113
  Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the MAXI event is high: 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 #34072
  V.Lipunov, A.Kuznetsov, N.Tiurina, E.Gorbovskoy, P.Balanutsa, K.Zhirkov, O.Gress, A.Chasovnikov, G.Antipov, D.Vlasenko, V.Senik, V.Topolev, Ya.Kechin, Yu.Tselik, Siyu Wu, D.Cheryasov, V.Shumkov, T.Pogrosheva (Lomonosov Moscow State University,SAI,Physics Department), C.Francile, F. Podesta, C.Lopez, R. Podesta (Observatorio Astronomico Felix Aguilar OAFA), D.Buckley (SAAO), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez,J.Martinez,A.Corella,L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), N.M.Budnev, O.Ershova (ISU,API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University), M.Gulyaev, E.Minkina (Lomonosov MSU)
  MASTER-OAFA obotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) pointed to MAXI/GSC GRB 230623A (Hagiwara et al. GCN 34068, Trigger=2023-06-23 07:23:37 UT, not came in socket, Tnotice(GCN)=09:39:20) at 2023-06-23 10:14:25UT through clouds with mlim=17.0 at first 6 images (sun alt.=-16 and sunrise), we don't find OT insode 0.23deg MAXI error-box by auto-detection system.
  We also made the difference with old MASTER image and didn't find new optical sources, that can be connected with GRB.
• GCN Circular #34073
  P. A. Evans (U. Leicester) reports on behalf of the Swift team:
  Swift has initiated a series of observations, tiled on the sky, of the MAXI GRB 230623A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00114
  Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the MAXI event is high: 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 #34081
  S. Dichiara (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
  Swift-XRT has performed follow-up observations of the MAXI-detected burst GRB 230623A in a series of observations tiled on the sky. The total exposure time is 1.8 ks, distributed over 7 tiles; the maximum exposure at a single sky location was 807 s. The data were collected between T0+19.9 ks and T0+38.0 ks, and are entirely in Photon Counting (PC) mode.
  No X-ray sources have been detected. The 3-sigma upper limit in the field (not including the regions where the tiles overlap) ranges from ~0.02 to ~0.23 ct s^-1, corresponding to a 0.3-10 keV observed flux of 6.1e-13 to 9.1e-12 erg cm^-2 s^-1 (assuming a typical GRB spectrum).
  The results of the XRT-team automatic analysis of the tiled XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/xrt_products/TILED_GRB00113.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #34139
  D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, Y. Temiraev, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
  The long-duration GRB 220623A (MAXI-GSC detection: Hagiwara et al., GCN 34068) was detected by Konus-Wind (KW) in the waiting mode.
  A Bayesian block analysis of the KW waiting mode data in the 20-1500 keV band reveals a multi-peaked structure which starts at ~T0 and ends at ~T0+580 s, where T0 = T0(MAXI) = 07:23:37 UT.
  The KW light curve of this burst is available at http://www.ioffe.ru/LEA/GRBs/GRB230623A/
  Modelling a time-integrated spectrum of the burst by a power law (PL) model dN/dE ~ E^alpha yields alpha = -2.18(-0.04,+0.05).
  The spectrum near the peak count rate, measured from T0+43.303 s to T0+75.687 s, can be described by a power law with exponential cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.58(-0.13, +0.15) and Ep = 243(-57,+141) keV.
  The total burst fluence is 5.77(-0.34,+0.52)x10^-5 erg/cm^2, and the 2.944 s peak energy flux is 6.08(-0.97,+1.40)x10^-7 erg/cm^2. (both in the 20 keV - 10 MeV energy range).
  All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.