The LIGO Open Science Center (LOSC) fulfills LIGOs commitment to release, archive, and serve LIGO data in a broadly accessible way to the scientific community and to the public, and to provide the information and tools necessary to understand and use the data. In August 2014, the LOSC published the full dataset from Initial LIGOs S5 run at design sensitivity, the first such large-scale release and a valuable testbed to explore the use of LIGO data by non-LIGO researchers and by the public, and to help teach gravitational-wave data analysis to students across the world. In addition to serving the S5 data, the LOSC web portal (losc.ligo.org) now offers documentation, data-location and data-quality queries, tutorials and example code, and more. We review the mission and plans of the LOSC, focusing on the S5 data release.
Advanced LIGO and Advanced Virgo will be all-sky monitors for merging compact objects within a few hundred Mpc. Finding the electromagnetic counterparts to these events will require an understanding of the transient sky at low red-shift (z<0.1). We performed a systematic search for extragalactic, low red-shift, transient events in the XMM-Newton Slew Survey. In a flux limited sample, we found that highly-variable objects comprised 10% of the sample, and that of these, 10% were spatially coincident with cataloged optical galaxies. This led to 4x10^-4 transients per square degree above a flux threshold of 3x10^-12 erg cm-2 s-1 [0.2-2 keV] which might be confused with LIGO/Virgo counterparts. This represents the first extragalactic measurement of the soft X-ray transient rate within the Advanced LIGO/Virgo horizon. Our search revealed six objects that were spatially coincident with previously cataloged galaxies, lacked evidence for optical AGNs, displayed high luminosities around 10^43 erg s-1, and varied in flux by more than a factor of ten when compared with the ROSAT All-Sky Survey. At least four of these displayed properties consistent with previously observed tidal disruption events.
