AstroNote 2020-129

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DRAFT
2020-06-29 18:45:02
Type: Object/s-Discovery/Classification
Pan-STARRS Search for Kilonovae: discovery of an intrinsically faint transient in GSG 039 (156 Mpc)
Authors: M. Fulton, S. J. Smartt, K. W. Smith (QUB), K. C. Chambers, M. Huber (IfA, Hawaii), S. Srivastav, 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 an intrinsically faint transient PS20eok (AT2020nrx) in the host galaxy GSG 039, at a redshift of z = 0.037 or or d = 156 Mpc (from NED). Its discovery magnitude (MJD = 59027.52) is w = 20.80 +/- 0.13, and hence an absolute magnitude of M_w = -15.3 +/- 0.2.

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 PS20eok (AT2020nrx) in the host galaxy GSG 039, at a redshift of z = 0.037 or d = 156 Mpc (from NED). The transient was discovered on MJD 59027.52 == 2020-06-27.52 at m_w = 20.80 +/- 0.13. It is offset from the host by 9.5" S, 9.6" E (a projected 10.6 kpc radius from the galaxy centre). At this distance the absolute magnitude is M_w = -15.3 (assuming m-M = 35.97 and foreground extinction of A_r = 0.17). Spectroscopic classification is encouraged. 

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

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. 

Show current TNS values
CatalogNameReported RAReported DECReported Obj-TypeReported RedshiftHost NameHost RedshiftRemarksTNS RATNS DECTNS Obj-TypeTNS Redshift
TNS2020nrx [PS20eok]21:05:21.105-25:34:08.96GSG 0390.03747321:05:21.105-25:34:08.96