Upper limits on the continuum radio emission of XRT 210423 from uGMRT observations
ATel #14735; Mayuresh Surnis (JBCA), Bhal Chandra Joshi (NCRA-TIFR), Yogesh Maan(ASTRON), Benjamin Stappers (JBCA), Fabian Jankowski (JBCA), Kaustubh Rajwade (JBCA), Manisha Caleb (JBCA)
on 23 Jun 2021; 08:39 UT
Credential Certification: Mayuresh Surnis (msurnis@gmail.com)
Subjects: Radio, Neutron Star, Transient, Magnetar
XRT 210423 was serendipitously detected by the Chandra X-ray telescope on 23 April 2021 while carrying out a calibration observation (Lin et al., ATEL #14599). Lin et al. suggested that the source properties resemble a magnetar. In order to detect a radio afterglow, we observed XRT 210403 with the upgraded Giant Metrewave Radio Telescope (uGMRT). These observations were carried out in band-4 (550-750 MHz) on 2021 June 3, 12:34 UT for an on-source time of about 60 minutes. We observed the nearby pulsar PSR B1237+25 as a test source.
We made a radio image of the field with a synthesized beam size of about 6.8" x 3.2" with a beam position angle of 81.2 degree. We do not detect any continuum emission at the position of the transient with a 3-sigma flux density upper limit of 750 microJy at 0.65 GHz.
We would like to note that there were multiple optical observations carried out to detect afterglow emission but all of these resulted in non-detections (ATELs #14600, #14610, #14635, #14640).
We thank the staff of the GMRT who have made these observations possible. GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research.
