AstroNote 2019-48

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DRAFT
2019-07-20 17:37:13
Type: Announcement-Campaign/Survey
Pan-STARRS Search for Kilonovae : discovery of an intrinsically faint transient in UGC 12798 (68 Mpc)
Authors: S. J. Smartt, (Queen's University Belfast), K. C. Chambers, (IfA, University of Hawaii) K. W. Smith (QUB), M. Huber (IfA), S. Srivastav, O. McBrien, D. R. Young, J. Gillanders, D. O'Neil, P. Clark, S. Sim, (QUB), T. de Boer, J. Bulger, J. Fairlamb, C.-C. Lin, T. Lowe, E. Magnier, A. Schultz, R. J. Wainscoat, M. Willman (IfA), T.-W. Chen (MPE), D. E. Wright (University of Minnesota), C. Stubbs (Harvard), A. Rest (STScI)
Source Group: Pan-STARRS1
Abstract:
We introduce a focused search for any intrinsically faint transients, or rapidly evolving transients in galaxies which are closer than 200 Mpc in the ongoing Pan-STARRS Near Earth Object surveys. The main goal is to highlight transients that may be kilonova candidates and are in the absolute magnitude range from approximately -10 to -15 (with or without a gravitational wave trigger). In this first AstroNote, we report the discovery of PS19dtj (AT2019lkf) in UGC 12798 (68Mpc), at mag z = 19.9, which implies an absolute magnitude of M_z =-14.4. Spectroscopic classification is encouraged.

We introduce a focused search for any intrinsically faint transients, or rapidly evolving transients in galaxies which are closer than 200 Mpc in the ongoing Pan-STARRS Near Earth Object surveys. In normal survey mode, 4 x 45s exposures in w, i or z are taken reaching each night reaching 5 sigma magnitudes of w<22, i<21 and z<20.5 (see Chambers et al. 2016, 1612.05560).

The main goal is to highlight transients that may be kilonova candidates and are in the absolute magnitude range from approximately -10 to -15 (with or without a gravitational wave trigger). This magnitude range brackets published models of r-process powered kilonovae and the peak magnitude of AT2017gfo. We caution that these will mostly be sub-luminous or old supernovae, reddened supernovae, giant eruptions of luminous blue variables , or bright classical novae, given the relative rate of such events compared to the rarity of kilonovae. However we encourage spectroscopic classification or photometric follow-up (to identify any fast fading) of these candidates. 

In the context of this "Pan-STARRS search for kilonovae", we report the discovery of an intrinsically faint transient on MJD 58680.60 == 2019-07-16.60, at z = 19.92 +/- 0.07. PS19dtj (AT2019lkf) is offset by 5.90 arcsec north, 13.04 arcsec east from UGC 12798, which is at z = 0.018 or d = 68 Mpc (from NED), implying an absolute magnitude of M = -14.4 (assuming m-M = 34.2 and A_z = 0.1).

Information on all objects discovered by the "Pan-STARRS search for kilonovae" will be made available at http://star.pst.qub.ac.uk/ps1threepi/. 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.

 

Show current TNS values
CatalogNameReported RAReported DECReported Obj-TypeReported RedshiftHost NameHost RedshiftRemarksTNS RATNS DECTNS Obj-TypeTNS Redshift
TNS2019lkf [PS19dtj]23:49:40.912+29:56:01.050.01823:49:40.912+29:56:01.05SN II0.018