Detection of Galactic X-ray transient EP240305a (EPW20240305aa) by ATCA radio telescope
ATel #16555; Tao An, Yuanqi Liu (SHAO), Hua Feng, Lian Tao (IHEP), Weimin Yuan (NAOC)
on 23 Mar 2024; 07:58 UT
Credential Certification: Tao An (antao@shao.ac.cn)
Subjects: Radio, Transient
We performed a radio observation of the newly discovered X-ray transient EP240305a (EPW20240305aa) detected by Einstein Probe (EP) and Swift/XRT (ATel #16509, ATel #16514) with the Australia Telescope Compact Array (ATCA) under project code CX563. Initial observations were made at 2.1 GHz from 2024-03-12 UT04:00 to 2024-03-12 UT06:30. Further observations of this source were conducted at 2.1 GHz, 5.5 GHz, and 9 GHz from 2024-03-16 UT03:00 to 09:30.
Preliminary results indicate the detection of the source with a peak flux density of ~300 microJy at both 5.5 and 9 GHz. However, it was not detected at 2.1 GHz on either 2024-03-12 or 2024-03-16 with noise levels around 10 microJy.
We plan to continue monitoring this source with ATCA. We extend our gratitude for the allocated observation time provided by ATCA and the observational support from Jamie Stevens.
The Australia Telescope Compact Array is a component of the Australia Telescope National Facility, a national resource funded by the Australian Government and managed by CSIRO.
Detailed results:
5.5 GHz peak flux density: 237 +/- 26 microJy/beam
9 GHz peak flux density: 357 +/- 28 microJy/beam
Spectral index: +0.83 (a rising spectrum)
Source position: RA (J2000) = 08:11:40.888, Dec (J2000) = -54:39:07.46
Combined C-band
7.25 GHz peak flux density: 317 +/- 20 microJy/beam
