MeerKAT observation of EP240309a (EP J115415.8-501810)
ATel #16572; Ning Chang (Xinjiang Astronomical Observatory, CAS, China), Pengfei Jiang (Xinjiang Astronomical Observatory, CAS, China), Jie Liao (Xinjiang Astronomical Observatory, CAS, China; University of Chinese Academy of Sciences, China), Lang Cui (Xinjiang Astronomical Observatory, CAS, China), Yongfeng Huang (Nanjing University, China), Tao An (Shanghai Astronomical Observatory, CAS, China), Hongmin Cao (Shangqiu Normal University, China), Wancheng Xu (Xinjiang Astronomical Observatory, CAS, China; University of Chinese Academy of Sciences, China)
on 5 Apr 2024; 12:29 UT
Credential Certification: Ning Chang (changning@xao.ac.cn)
Subjects: Radio, Transient
We observed the X-ray flare EP240309a/EP J115415.8-501810 (Line et al., ATEL #16546) on March 30, 2024, at 1.28 GHz using the MeerKAT radio telescope with 1-hour on-source time. The schedule block ID is 20240328-0006. EP240309a/EP J115415.8-501810 is likely a cataclysmic variable (Line et al., ATEL #16546; Rodriguez et al., ATEL #16549), and exhibits a strong 3.762 h periodicity and related first harmonic based on optical observations (Buckley et al., ATEL #16554). From the South African Radio Astronomy Observatory Science Data Pipeline (SDP) image, there is no radio counterpart was detected with the image rms of 20 uJy/beam in the field given by the Einstein Probe mission within the radius of 10 arcsec (the uncertainty of the Follow-up X-ray Telescope [FXT]). Here we report a 3-sigma upper limit of 60 uJy/beam. However, we note that there is a radio detection with 180 uJy/beam which is about 30 arcsec away from the FXT position (3 times uncertainty) and about 20 arcsec away from the optical counterpart (Gaia position). Further data calibration and imaging will be performed to get a deep and clear image.
For the SDP image, please visit https://drive.google.com/file/d/1TVtgoU2jw1OE5UCVihY5y6l8H41-zcS5/view?usp=sharing. The white cross in the figure is the FXT position and the circle radius is 30 arcsec, the red cross is the Gaia position.
We would like to thank the MeerKAT science operations team for scheduling the follow-up observation immediately. The MeerKAT telescope is operated by the South African Radio Astronomy Observatory, which is a facility of the National Research Foundation, an agency of the Department of Science and Innovation.
