AstroNote 2020-104

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DRAFT
2020-05-15 23:50:16
Type: Object/s-Discovery/Classification
Pan-STARRS Search for Kilonovae: discovery of an intrinsically faint transient in a satellite of SDSS J153044+075212.4 (193 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 PS20dan (AT2020jwm) in what may possibly be a satellite galaxy of galaxy SDSS J153044+075212.4, located at a redshift of z = 0.045 or d = 193 Mpc (from NED). Its discovery magnitude (MJD = 58981.34) is w = 21.35 +/- 0.15, and hence an absolute magnitude of M_w = -15.19 +/- 0.21.

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.

Show current TNS values
CatalogNameReported RAReported DECReported Obj-TypeReported RedshiftHost NameHost RedshiftRemarksTNS RATNS DECTNS Obj-TypeTNS Redshift
TNS2020jwm [PS20dan]15:30:43.582+07:52:12.80SDSS J153044+075212.40.04492215:30:43.582+07:52:12.80