GRB 230204B: MAXI/GSC detection
Abstract
The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 21:47:51 UT on 4 Feb 2023. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (197.581 deg, -21.752 deg) = (13 10 19, -21 45 07) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.12 deg and 0.1 deg, respectively. The roll angle of long axis from the north direction is 156.0 deg counterclockwise. Without assumptions on the source constancy, we obtain a rectangular error box for the transient source with the following corners. (196.900, -21.911) deg = (13 07 36, -21 54 39) (J2000) (196.998, -22.143) deg = (13 07 59, -22 08 34) (J2000) (198.373, -21.637) deg = (13 13 29, -21 38 13) (J2000) (198.273, -21.406) deg = (13 13 05, -21 24 21) (J2000) There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 628 +- 49 mCrab (4.0-10.0keV, 1 sigma error). There was no significant excess flux in the previous transit at 20:15 UT with an upper limit of 20 mCrab.
- Publication:
-
GRB Coordinates Network
- Pub Date:
- February 2023
- Bibcode:
- 2023GCN.33265....1S