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AMI observations of ASASSN transients (16hf and 16hq)

ATel #9382; K. P. Mooley, R. P. Fender (Oxford), T. Cantwell (Manchester), Y. C. Perrott, D. Titterington, S. H. Carey, J. Hickish, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester)
on 17 Aug 2016; 14:14 UT
Credential Certification: Kunal Mooley (kunal.mooley@physics.ox.ac.uk)

Subjects: Radio, Optical, Nova, Star, Transient, Variables

We observed the M31 nova ASASSN-16hf (alias iPTF16bqy, ATel #9245, #9248, #9329) with the AMI Large Array at 15 GHz on 2016 August 06.13 UT, ~22 days post-discovery. We obtain a 3sigma upper limit of 102 uJy, corresponding to a spectral luminosity of 7.4e22 erg/s/Hz.

On 2016 July 26.95 UT we followed up ASASSN-16hq, a very large ~8 mag stellar flare from an M8 dwarf (http://www.astronomy.ohio-state.edu/~assassin/transients.html). We observed with the AMI Small Array at 15 GHz starting ~18 hours post-discovery. No radio emission was detected from 16hq; the 3sigma upper limit is 1.2 mJy, corresponding to a spectral luminosity of 1.4e16 erg/s/Hz at an estimated photometric parallax distance of 100 pc. The non-detection precludes a strong long-lasting radio flare (comparable to DG CVn; Fender et al. 2015, MNRAS, 446, 66) accompanying the optical flare.

These upper limits may be useful in constraining the energetics and/or physical parameters associated with these transients. We thank the AMI staff for scheduling these observations.