DRAFT
2021-04-27 00:51:06
Type: Object/s-Discovery/Classification
Pan-STARRS Search for Kilonovae: discovery of 2 intrinsically faint transients within 100 Mpc
Authors: S. Srivastav, S. J. Smartt, K. W. Smith (QUB), K. C. Chambers, M. Huber (IfA, Hawaii), O. R. McBrien, D. R. Young, J. Gillanders, 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-STARRS
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 2 intrinsically faint transients PS21dkh (AT2021kmo) at z = 0.023 and PS21dki (AT2021kmp) at z = 0.021. The w-band absolute magnitudes for PS21dkh and PS21dki are -14.1 and -13.0, respectively.

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 PS21dkh (AT2021kmo) in the host galaxy KUG 1138+291, at a redshift of z = 0.023, or d = 99 Mpc (from NED); and PS21dki (AT2021kmp) in the host galaxy UGC 06204, at a redshift of z = 0.021, or d = 90 Mpc (NED). PS21dkh was discovered on MJD 59320.28 (2021-04-16.28 UTC) at mag w = 20.92 +/- 0.06. It is offset from the host by 4.0" N, 5.1" E (a projected 3.1 kpc radius from the galaxy centre). At this distance the absolute magnitude for PS21dkh is M_w = -14.1 +/- 0.2 (assuming m-M = 34.99 and foreground exinction of  A_w = 0.05). PS21dki was discovered on MJD 59321.25 (2021-04-17.25 UTC) at mag w = 21.84 +/- 0.18. It is offset from the host by 18.6" N, 7.9" E (a projected 8.6 kpc radius from the galaxy centre). At this distance the absolute magnitude for PS21dki is M_w = -13.0 +/- 0.2.

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
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 2021kmo [PS21dkh] 11:40:39.633 +28:51:53.98 KUG 1138+291 0.022766 11:40:39.633 +28:51:53.98
TNS 2021kmp [PS21dki] 11:09:52.061 +24:16:00.49 UGC 06204 0.020591 11:09:52.061 +24:16:00.49

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