GRB 240214A/1H 0451-560: MAXI/GSC detection
Abstract
The MAXI/GSC nova alert system triggered on an uncatalogued soft X-ray transient source at 01:43:39 UT on February 14, 2024. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (73.197 deg, -55.923 deg) = (04 52 47, -55 55 22) (J2000) with a 90% C.L. statistical error of 0.42 deg and an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 109 +- 24 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: (73.301, -55.429) deg = (04 53 12, -55 25 44) (J2000) (72.444, -56.103) deg = (04 49 46, -56 06 10) (J2000) (74.543, -56.916) deg = (04 58 10, -56 54 57) (J2000) (75.381, -56.228) deg = (05 01 31, -56 13 40) (J2000) The burst showed a spectral softening during the burst duration of about 30 sec (in the MAXI scan window), and the average spectrum is characterized by a power-law with a photon index of 2.3 (+0.8, -0.6) at a 90% confidence level. An X-ray flux of about 20 mCrab at 2-10 keV was also recognized in the next transit at 03:16 UT. There was no significant excess flux in the previous transit at 00:10 UT, and in the transit at 04:49 UT with an upper limit of 20 mCrab for each. We note that 1H 0451-560 is located near the center of the error region. 1H 0451-560 is a short-lived transient X-ray source with a Crab-like spectrum (Kaluzienski 1978, IAUC 3174). Thus, 1H 0451-560 is most likely. We also tentatively name the source MAXI J0452-559. Swift/XRT followup observation is requested. We crosspost this content to the Astronomer's Telegram because of the possible nature of the source.
- Publication:
-
GRB Coordinates Network
- Pub Date:
- February 2024
- Bibcode:
- 2024GCN.35721....1N