The spectroscopic classification of four transients in the Pan-STARRS1 3Pi Faint Galaxy Supernova Survey and PSN J21215870-1351224.

ATel #4231; D. Wright, M. Fraser, S. J. Smartt, S. Valenti, R. Kotak, L. Magill, M. McCrum, K. Smith, T.-W. Chen, (Queen's University Belfast), F. Bresolin, R. Kudritzki, J. Tonry, E. Magnier, M. Huber, K. Chambers, N. Kaiser, J. Morgan, W. Burgett, J. Heasley, W. Sweeney, C. Waters, H. Flewelling (University of Hawaii), C. Stubbs (Harvard), P. A. Price (Princeton)
on 30 Jun 2012; 19:25 UT
Credential Certification: Morgan Fraser (mfraser02@qub.ac.uk)

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Further to Valenti et al. (ATels #2668, #3351) we report the independent discovery and spectroscopic confirmation of two SNe and two QSOs in the Pan-STARRS1 3Pi Faint Galaxy Supernova Survey.

PS1-12axn (16:50:29.65 +45:44:19.2) was discovered on 16 Jun 2012 at g=17.7 (in PS1 system ; see Tonry et al. 2012, ApJ, 745, 42), offset by 0.31" from the galaxy SDSS J165029.63+454419.0 (g=22.23). This is the CRTS source CSS120610:165030+454419 first discovered on 10 Jun 2012 at an unfiltered magnitude of 18.6±0.1. A spectrum obtained on Jun 26 at the 4.2m William Herschel Telescope with ISIS (range 400-950nm) and fitted using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, ApJ, 666, 1024), shows it to be a normal type Ia supernova a few days after maximum at z=0.06.

PS1-12axo (16:52:35.26 +39:02:08.5) was found at i=19.8 on 06 Jun 2012 offset from the galaxy SDSS J165235.09+390206.4 (i=20.8) by 2.73". A spectrum from the WHT+ISIS on Jun 26 (range 400-950nm) shows that the transient is a normal type Ia supernova approximately 2 weeks after peak at z=0.14.

PS1-12axm (16:46:32.10 +76:01:23.1) was discovered at i=19.5 on 05 Jun 2012 and is coincident with the centre of the galaxy SDSS J164632.09+760123.1 (i=20.56). A spectrum from the WHT+ISIS on Jun 26 (range 400-950nm) shows PS1-12axm to be an AGN/QSO with strong narrow emission at 769nm, 760nm, 746nm and 572nm consistent with [OIII] 501nm, [OIII] 496nm, H-beta 486nm and [OII] 373nm at z=0.534. There are also broad features at 769nm and 424nm corresponding to MgII and a broad H-beta component at this redshift.

PS1-12axg (16:38:38.44 +35:20:59.11) was discovered at z=20.0 on 13 Mar 2012. The transient is coincident with the stellar source SDSS J163838.41+352059.2 (z=20.61). A spectrum from the WHT+ISIS (range 400-950nm) on Jun 27 shows a blue continuum with strong broad emission lines at 415.7nm and 611.1nm. The feature at 611.1 nm is likely MgII 280nm at a redshift of z=1.18, the feature at 415.7nm may then be CIII 190nm. The SDSS colours are also suggestive of a QSO.

We also report a spectroscopic classification of PSN J21215870-1351224 (21:21:58.70 -13:51:22.40), which was discovered at mag~19.2 in IR imaging on 16 May 2012 by Joseph Brimacombe (http://www.cbat.eps.harvard.edu/unconf/followups/J21215870-1351224.html). A spectrum obtained from the WHT+ISIS (range 380-900nm) on May 27 shows a red continuum with broad features in the blue. This is suggestive of a reddened BL Lac-type object at a redshift of z~0.5. However, the transient is offset from the apparent host USNOA2 0750-20769751, indicating that this is not the true host, which may instead be a background galaxy unassociated with USNOA2 0750-20769751.

This discovery was enabled using the PS1 System operated by the PS1 Science Consortium (PS1SC) and its member institutions, http://ps1sc.org/PS1_System_ATel.shtml. We would like to thank the PS1 telescope operators for their support of PS1 observations.