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The Pan-STARRS Survey for Transients (PSST) - first announcement and public release

ATel #7153; M. Huber, K. C. Chambers, H. Flewelling, M. Willman, N. Primak, A. Schultz, B. Gibson, E. Magnier, C. Waters, J. Tonry, R. J. Wainscoat (IfA, Hawaii), K. W. Smith, D. Wright, S. J. Smartt (Queen's University Belfast), R. J. Foley (Illinois), S. W. Jha (Rutgers), A. Rest (STScI), D. Scolnic (Chicago/KICP)
on 27 Feb 2015; 15:48 UT
Credential Certification: Stephen Smartt (s.smartt@qub.ac.uk)

Subjects: Optical, Supernovae

Further to ATel #5850 (Smartt et al.2014), we report that the Pan-STARRS1 Science Consortium finished their search for transients in the PS1 3Pi sky survey in mid-2014. Since then, the PS1 telescope has been running a wide-field survey for near earth objects, funded by NASA through the NEO Observation Program. This survey takes data in w-band in dark time, and combinations of i, z and y during bright moon. The data are processed through the IPP difference imaging pipeline at the IfA in Hawaii and the Transient Science Server at Queen's University Belfast. Stationary transients are recovered and quantified.

Effectively the 3Pi survey for transients that started during the PS1 Science Consortium is being continued under the new NEO optimised operations mode. The observing procedure in this case is to take a quad of exposures, typically 30-45s separated by 10-20mins each. This cadence may be repeated on subsequent nights.

PS1 is also beginning observations for the Foundation Supernova Survey, a low-z SN Ia survey which plans to observe several hundred z < 0.1 SNe Ia over the next few years. These observations consist of a series of griz imaging and a cadence of roughly 5 days. The subset of SNe discovered by PSST in the Foundation data will have early color information.

We are publicly releasing PSST discovered transients, with the first 218 from 1st February 2015 now available. These are mostly supernova candidates, but the list also contains some variable stars, AGN, and nuclear transients (defined on the webpages). The web page listing will be continuously updated with new detections and is available here :

http://star.pst.qub.ac.uk/ps1threepi/

Where possible, we have cross-matched the detections with transient objects already discovered and announced in Astronomer's Telegrams, CBETs, and on publicly accessible webpages such as those of the Catalina Real Time Transient Survey (http://crts.caltech.edu), the ASASSN survey (http://www.astronomy.ohio-state.edu/~assassin/transients.html), PESSTO and LSQ (www.pessto.org).

The first of these discoveries from the Pan-STARRS Survey for Transients were classified by PESSTO in ATels #6928, #6965, #7091, #7102, Here we report a further classification of a PSST object (PS15da, also recorded as CSS150222-081510+173959 by CRTS). A spectrum was obtained on 23 Feb. 2015 with the SNIFS spectrograph on the UH 2.2m telescope (range 330-970nm, resolution R~1000) and the classification was done using SNID (Blondin and Tonry 2007, ApJ, 666, 1024).

 
Object | RA          | DEC          | Disc.   | Mag(filt) | Type | Redshift | comments  
PS15da | 08:15:10.09 | +17:39:58.5  |20150218 | 18.53(w)  | Ia   | 0.063    | around max 

Operation of the Pan-STARRS1 telescope is supported by the National Aeronautics and Space Administration under Grant No. NNX12AR65G and Grant No. NNX14AM74G issued through the NEO Observation Program.