AMI-LA radio upper limits of the nuclear optical transient AT2019PEV
ATel #13135; David Williams, Rob Fender (Oxford), Dave Green, David Titterington (Cambridge), Yvette Perrott (VUW)
on 26 Sep 2019; 15:35 UT
Credential Certification: David Williams (david.williams@physics.ox.ac.uk)
Subjects: Radio, AGN, Black Hole, Transient
We report 15.5 GHz Arcminute Microkelvin Imager Large Array (AMI-LA; Zwart et al. 2008; Hickish et al. 2018) observations of the nuclear optical transient AT2019pev (ATel #13127, ATel #13132). We started observing the source on 2019-09-26.1 for 4 hours. 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 J0424+0204 as the interleaved phase calibrator.
We performed a preliminary analysis of the data and do not detect any emission at the position of AT2019pev in the phase centre of the image. This implies that the nearby NVSS source 7 arcsec away from AT2019pev reported in ATel #13127, is also not detected, as it is within the AMI-LA synthesized beam (30 arcsec). Our limit is consistent with optically thin emission from this NVSS source, given that we observed at a higher frequency than NVSS, and does not imply variability. The rms noise in the phase centre is 0.16mJy/beam, allowing us to set a 3 sigma upper limit of 0.48mJy/beam for AT2019pev. However, we do detect a separate NVSS source, NVSS J042925+003306 at a peak flux density of 5.7+-0.1mJy/beam in the field.
We plan to continue monitoring this source and would like to thank the MRAO staff for carrying out these observations.
