AMI-LA 15.5 GHz observations of AT2018cow
ATel #11774; Joe Bright (University of Oxford), Assaf Horesh (Hebrew University of Jerusalem), Rob Fender, Sara Motta (University of Oxford), Itai Sfaradi (Hebrew University of Jerusalem), David Titterington, Yvette Perrott (MRAO, University of Cambridge), Anna Ho (Caltech)
on 24 Jun 2018; 16:23 UT
Credential Certification: Sara Elisa Motta (sara.motta@physics.ox.ac.uk)
Subjects: Radio, Transient
We have observed the field of AT2018cow/ATLAS18qqn (ATel #11727) with the Arcminute Microkelvin Imager Large Array (AMI-LA; Zwart et al. 2008; Hickish et al. 2018) on 2018-06-22.71 at a central frequency of 15.5 GHz across a 5 GHz bandwidth. We observed for 8.8 hours and clearly detect an unresolved source at the phase centre. Fitting the source with the CASA task IMFIT provides an integrated flux density of ~0.5 mJy (a > 5-sigma detection) and a position of RA: 16:16:00.4, Dec: +22 16 06.4 with a synthesised beam major and minor FWHM of 47 and 34" respectively (consistent with the position reported in ATel #11727).
The custom pipeline REDUCE_DC (e.g. Perrott et al. 2015) was used to calibrate and flag the data, with 3C286 as the absolute flux calibrator and J1619+2247 as the interleaved phase calibrator.
We plan to continue monitoring this source, and would like to thank the MRAO staff for carrying out these observations.