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, arXiv:1612.05560).
We report the discovery of a (possible) intrinsically faint transient PS20kxg (AT2020zck) with PS2. It is offset from a possible host (14.6" N, 54.2" E) 2MASXJ00085765-0836093 which has a redshift of z = 0.108, or d = 75 Mpc (from NED). The transient was discovered at MJD 59161.275 (2020-11-08 06:36 UTC) at mag w = 20.5 +/- 0.1. At this distance the absolute magnitude is M_w = -14.0 +/- 0.1 (assuming m-M = 34.4 and foreground exinction of A_w = 0.1).
ZTF detected AT2020zck (see lightcurve on Lasair, object ZTF20acppuiq ) on 59164.3 at r = 20.2 +/- 0.3 and g = 19.9 +/- 0.3, and the recent lightcurve points are given below. The uncertainties on the ZTF magnitudes are large, but could imply a large colour change. Non-detections by PS1, ATLAS and ZTF imply this is not a normal, old supernova in 2MASXJ00085765-0836093 . Given it is offset from the host (22 kpc projected), intrinsically faint and (possibly) an unusual colour change, follow-up is encouraged.
It could also be a background SN or foreground galactic outburst. There is no obvious distant host galaxy in the PS1 3Pi grizy stacks, but a faint source marginally detected, is visible in our w-band reference stack. This could imply a background galaxy or satellite of 2MASXJ00085765-0836093.
59111.478 w PS2 >21
59158.227 r ZTF >19.8
59158.195 g ZTF >19.8
59160.400 o ATLAS >19.7
59161.275 w PS2 20.50 +/- 0.1
59164.253 g ZTF 19.86 +/- 0.31
59164.277 r ZTF 20.19 +/- 0.28
59165.171 g ZTF 20.65 +/- 0.25
59165.212 r ZTF 20.30 +/- 0.17
59167.372 w PS1 20.35 +/- 0.07
The discoveries from this program are a byproduct of the Pan-STARRS NEO survey observations. Operation of the Pan-STARRS1 and Pan-STARRS2 telescopes is primarily supported by the National Aeronautics and Space Administration under Grant No. NNX12AR65G and Grant No. NNX14AM74G issued through the SSO Near Earth Object Observations Program. Data are processed at Queen's University Belfast enabled through the STFC grants ST/P000312/1 and ST/T000198/1.
Catalog | Name | Reported RA | Reported DEC | Reported Obj-Type | Reported Redshift | Host Name | Host Redshift | Remarks | TNS RA | TNS DEC | TNS Obj-Type | TNS Redshift |
---|---|---|---|---|---|---|---|---|---|---|---|---|
TNS | 2020zck [PS20kxg] | 00:09:01.318 | -08:35:54.68 | 0.018 | 00:09:01.327 | -08:35:54.70 |