ATCA detection of the X-ray transient EP240904a
ATel #16817; Ailing Wang, Hua Feng (IHEP), Tao An (SHAO), Yanan Wang (NAOC), Lian Tao, Liang Zhang (IHEP), Zikun Lin (NAOC), Long Ji (SYSU), Shuang-Nan Zhang (IHEP)
on 18 Sep 2024; 12:38 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Yanan Wang (wyn4032@icloud.com)
Subjects: Radio, Binary, Black Hole, Transient
Referred to by ATel #: 16825
Following the EP detection of the X-ray transient EP240904a (Atel #16805), we triggered a 5-hour observation using the Australia Telescope Compact Array (ATCA) in the C band, with central frequencies of 5.5 GHz and 9 GHz, and a bandwidth of 2 GHz each. This observation was conducted 8 days after the discovery, from 2024-09-12 09:00 to 14:00 (UTC).
We successfully detected a radio source at a position spatially coincident with EP240904a. Our preliminary analysis yields the following coordinates and peak flux densities for the radio counterpart:
At 5.5 GHz:
RA (J2000) = 18h 27m 30.16s +- 0.24s;
DEC (J2000) = -09d 56m 35.99s +- 3.51s;
Peak flux density = 101.2 +- 5.4 microJy.
At 9.0 GHz:
RA (J2000) = 18h 27m 30.07s +- 0.18s;
DEC (J2000) = -09d 56m 40.38s +- 2.09s;
Peak flux density = 126.3 +- 5.2 microJy.
We will continuously monitor this transient with EP and ATCA, and multiwavelength follow-ups are encouraged.
