AstroNote 2019-81

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DRAFT
2019-08-29 00:16:40
Type: Object/s-Discovery/Classification
Pan-STARRS Search for Kilonovae: discovery of two intrinsically faint transients (AT2019ouq at 158 Mpc and AT2019ovs at 203 Mpc) with Pan-STARRS2
Authors: K. C. Chambers, M. Huber (IfA, Hawaii), S. J. Smartt, K. W. Smith, 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 (MPE), 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). As part of its scientific commissioning we report discovery of the first transients by Pan-STARRS2. Pan-STARRS2 is a second 1.8m telescope, with a similar 1.4 gigapixel camera, co-located with Pan-STARRS1 at Haleakala. We refer to the twin telescope system as Pan-STARRS, and they will be operated together for NEO surveys and other smaller focused programmes. PS19eur (AT2019ouq) is in the host galaxy 2MASX J17014143+3006403, at a redshift of z = 0.036, or d = 158 Mpc (from NED). PS19eux (AT2019ovs) is in the host galaxy 2MASX J00411796-0201084, at a redshift of z = 0.049, or d = 203 Mpc (from NED).  

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).

As part of its scientific commissioning we report discovery of the first transients by Pan-STARRS2. Pan-STARRS2 is a second 1.8m telescope, with a similar 1.4 gigapixel camera, co-located with Pan-STARRS1 at Haleakala. We refer to the twin telescope system as Pan-STARRS, and they will be operated together for NEO surveys and other smaller focused programmes.

PS19eur (AT2019ouq) in the host galaxy 2MASX J17014143+3006403, at a redshift of z = 0.036 or d = 158 Mpc (from NED).  The transient was discovered at MJD 58720.26 == 2019-08-25.26, at m_w = 21.27 +/- 0.13. It is offset from the host by 5.59" S, 6.12" E (a projected 5.9 kpc radius from the galaxy centre). At this distance the absolute magnitude is M_w = -14.79 (assuming m-M = 35.99 and foreground extinction of A_r = 0.068).  The transient was also recovered in i-band data from Pan-STARRS1, indicating while this is in the luminosity range of kilonovae, it is likely an old, fading supernova.

MJD Date m dm
58684.44 2019-07-20.44 19.61 0.26
58707.30 2019-08-12.30 20.20 0.17
58714.39 2019-08-19.39 20.47 0.23

 

PS19eux (AT2019ovs) is in the host galaxy 2MASX J00411796-0201084, at a redshift of z = 0.049 or d = 203 Mpc (from NED).  The transient was discovered at MJD 58721.48 == 2019-08-26.48, at m_w = 20.09 +/- 0.14. It is offset from the host by 1.68" S, 3.39" E (a projected 3.6 kpc radius from the galaxy centre). At this distance the absolute magnitude is M_w = -16.65 (assuming m-M = 36.68 and foreground extinction of A_r = 0.064).

We will release AstroNotes for all such intrinsically faint candidates and encourage spectroscopic classification and 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
TNS2019ouq [PS19eur]17:01:41.925+30:06:34.34SN0.03617:01:41.925+30:06:34.34
TNS2019ovs [PS19eux]00:41:18.191-02:01:10.26SN0.04900:41:18.196-02:01:10.26