AstroNote 2020-104

We are carrying out the "Pan-STARRS Search for Kilonovae" which is a focused search for intrinsically faint transients, or rapidly evolving transients in galaxies which are closer than 200 Mpc in the ongoing Pan-STARRS Near-Earth Object surveys (see Smartt et al. AstroNote 2019-48 for details). 

In normal survey mode, Pan-STARRS takes 4 x 45s exposures in w, i or z each night reaching 5 sigma magnitudes of w<22, i<21 and z<20.5 in each frame (see Chambers et al. 2016, 1612.05560). 

We report the discovery of an intrinsically faint transient PS20dan (AT2020jwm) in what may possibly be a satellite galaxy of galaxy SDSS J153044+075212.4, which is at a redshift of z = 0.045 or d = 193 Mpc (from NED). The transient was discovered at MJD 58981.34 == 2020-05-12.34 at mag w = 21.35 +/- 0.15. There was no detection by Pan-STARRS on MJD 58966.56 == 2020-04-27.56 suggesting this is not an old supernova. The transient is offset from the major galaxy SDSS J153044+075212.4 by 0.4" N, 7.0" W (a projected 6.2 kpc radius from the galaxy centre). At this distance, the absolute magnitude is M_w = -15.19 (assuming m-M = 36.43 and foreground extinction of  A_w = 0.11). Spectroscopic classification is strongly encouraged. 

We will release AstroNotes for all these candidates and encourage spectroscopic classification or photometric follow-up.  A finder is attached. 

These discoveries are a byproduct of the Pan-STARRS NEO survey observations supported by the NASA Grants, including No. NNX14AM74G issued through the SSO Near-Earth Object Observations Program.