{% extends "base_bootstrap.html" %} {% block title %}Pan-STARRS Transients{% endblock %} {% block celestial %} {% endblock %} {% block content %}
The Pan-STARRS1 telescope carried out the 3Pi survey of the whole sky north of -30 degrees between 2010-2014 in grizy (PS1 specific filters). This was run by the PS1 Science Consortium. Each region on the sky was typically visited four times a year in each filter. As described in Magnier et al. (2013, ApJS, 205, 20) and Inserra et al. (2013, ApJ, 770, 128) the four epochs were typically split into two pairs called Transient Time Interval (TTI) pairs which are single observations separated by 20-30 minutes to allow for the discovery of moving objects. The exposure times at each epoch (i.e. in each of the TTI exposures) were 43 s, 40 s, 45 s, 30 s, and 30 s in grizy(PS1). An all sky image of these stacked frames between 2010-2012 has been created in each band (internally called Processing Version 1) and all individual exposures since mid-June 2013 were differenced with respect to this static sky and transient sources have been catalogued. We typically reached high confidence transients (greater than 5-sigma) at depths of approximately 21.0, 20.6, 20.7, 20.4, and 18.3 (AB mags) in the grizy PS1 filters.
The Pan-STARRS1 Science Consortium finished this sky survey and since mid-2014 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 time. We are now processing these data through the PS1 IPP difference imaging pipeline and recovering stationary transients. 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.
In ATel 5850, we announced the public release of the first 880 transients from the PS1 3Pi survey, during the search period September 2013 - January 2014. These are mostly supernova candidates, but the list also contained some variable stars, AGN, and nuclear transients (defined below). The lightcurves are too sparsely sampled to be of standalone use, but they may be of use to the community in combining with existing data (e.g. Fraser et al. 2013, ApJ, 779, L8), constraining explosion and rise times (e.g. Nicholl et al. 2013, Nature, 502, 346) as well as many being new discoveries.
In ATel 7153 (Huber et al. 2015) we publicly announced the start of new data processing and transient searching beginning February 2015 using the data from the the Pan-STARRS NEO Science Consortium.