Gamma-ray Burst 180829A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN NOTICE
  

  TITLE:           GCN/MAXI NOTICE
  NOTICE_DATE:     Wed 29 Aug 18 06:59:23 UT
  NOTICE_TYPE:     MAXI Unknown Source Position
  EVENT_ID_NUM:    359039177     
  EVENT_RA:         61.73d {+04h 06m 55s} (J2000),
                    61.96d {+04h 07m 52s} (current), 
                    61.10d {+04h 04m 23s} (1950)
  EVENT_DEC:        -1.98d {-01d 58' 32"} (J2000),
                    -1.93d {-01d 55' 36"} (current),
                    -2.11d {-02d 06' 32"} (1950)
  EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
  EVENT_FLUX:      71.0 +- 0.0 [mCrab]
  EVENT_DATE:      18359 TJD;   241 DOY;   18/08/29
  EVENT_TIME:      331.00 SOD {00:05:31.00} UT
  EVENT_TSCALE:    30s
  EVENT_EBAND:     Low, 2-4 keV
  SUN_POSTN:       157.69d {+10h 30m 46s}   +9.34d {+09d 20' 38"}
  SUN_DIST:         95.96 [deg]  
  MOON_POSTN:        8.81d {+00h 35m 15s}   -1.19d {-01d 11' 27"} 
  MOON_DIST:        53.14 [deg]  
  MOON_ILLUM:      93 [%]        
  GAL_COORDS:      193.26,-36.93 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:       59.19,-22.44 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.
  

• GCN Circular #23186
  S. Yamada (Kyoto U.), H. Negoro (Nihon U.), M. Serino (AGU), M. Nakajima, A. Sakamaki, W. Maruyama (Nihon U.), T. Mihara, S. Nakahira, F. Yatabe, Y. Takao, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, Y. Kawakubo, T. Hashimoto, A. Yoshida (AGU), N. Kawai, M. Sugizaki, Y. Tachibana, K. Morita (Tokyo Tech), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe, R. Shimomukai (JAXA), Y. Ueda, A. Tanimoto, T. Morita (Kyoto U.), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), M. Yamauchi, K. Hidaka, S. Iwahori (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), M. Shidatsu (Ehime U.) report on behalf of the MAXI team:
  The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 2018-08-29T00:05:31UT . Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (61.729 deg, -1.976 deg) = (04 06 54, -01 58 33) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.36 deg and 0.29 deg, respectively. The roll angle of long axis from the north direction is 53.0 deg counterclockwise. Without assumptions on the source constancy,we obtain a rectangular error box for the transient source with the following corners:

  (60.951, -3.048) deg = (04 03 48, -03 02 54) (J2000)
  (60.690, -2.747) deg = (04 02 45, -02 44 49) (J2000)
  (62.767, -0.848) deg = (04 11 04, -00 50 53) (J2000)
  (63.028, -1.149) deg = (04 12 06, -01 08 57) (J2000)
  

  There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 71 +- 17 mCrab (4.0-10.0keV, 1 sigma error). There was no significant excess flux in the previous transit at UT 8/28 22:32 and in the next transit at 03:10 UT with an upper limit of 20 mCrab for each.
• GCN Circular #23187
  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 180829A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00073
  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 #23192
  J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
  Swift-XRT has performed follow-up observations of the MAXI-detected burst GRB 180829A (Yamada et al. GCN Circ. 23186) in a series of observations tiled on the sky. The total exposure time is 1.4 ks, distributed over 7 tiles; the maximum exposure at a single sky location was 420 s. The data were collected between T0+56.4 ks and T0+57.9 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 ~0.03 to ~0.11 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.1e-12 to 4.4e-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 http://www.swift.ac.uk/xrt_products/TILED_GRB00073.
  This circular is an official product of the Swift-XRT team.