AstroNote 2019-145

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DRAFT
2019-12-02 19:37:10
Type: Object/s-Discovery/Classification
Pan-STARRS Search for Kilonovae: discovery of intrinsically faint transients in SDSS J075545.25+322423.1 (181 Mpc) and PGC176183 (151 Mpc)
Authors: S. Srivastav, S. J. Smartt, K. W. Smith (QUB), K. C. Chambers, M. Huber (IfA, Hawaii), O. McBrien, D. R. Young, J. Gillanders, D. O'Neill, 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 (Stockholm), D. E. Wright (University of Minnesota), C. Stubbs (Harvard), A. Rest (STScI)
Source Group: Pan-STARRS1
Abstract:
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).  Here we report the discovery of intrinsically faint transients PS19gut (AT2019vve) in the host galaxy SDSS J075545.25+322423.1 (z = 0.042) and PS19gus (AT2019vuh) in the host galaxy PGC176183 (z = 0.036).

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 intrinsically faint transients PS19gut (AT2019vve) in the host galaxy SDSS J075545.25+322423.1 at a redshift of z = 0.042, or d = 181 Mpc (from NED); and PS19gus (AT2019vuh) in the host galaxy PGC176183 at a redshift of z = 0.036 or d = 151 Mpc (from NED).  PS19gut (offset 1.5 arcsec south, 2.9 arcsec east or 1.9 kpc from host centre) was discovered at MJD 58816.62 (2019-11-29.62) at mag w = 19.89 +/- 0.05. PS19gus (offset 9.3 arcsec south, 20.3 arcsec east or 22 kpc from host centre) was discovered at MJD 58815.36 (2019-11-28.36) at mag w = 19.86 +/- 0.03. The absolute magnitude for PS19gut is M_w = -16.5 (assuming m-M = 36.29 and foreground exinction of  A_w = 0.15) and PS19gus is M_w = -16.1 (assuming m-M = 35.90 and foreground extinction A_w = 0.05). Spectroscopic classification is encouraged. 

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.