KSwAGS: A Swift X-ray and UV Survey of the Kepler Field. I

We introduce the first phase of the Kepler–Swift Active Galaxies and Stars survey (KSwAGS), a simultaneous X-ray and UV survey of ~6 square degrees of the Kepler field using the Swift X-ray telescope (XRT) and UV/Optical Telescope. We detect 93 unique X-ray sources with signal-to-noise ratio ⩾ 3 with the XRT, of which 60 have UV counterparts. We use the Kepler Input Catalog (KIC) to obtain the optical counterparts of these sources, and construct the f_X/f_V ratio as a first approximation of the classification of the source. The survey produces a mixture of stellar sources, extragalactic sources, and sources which we are not able to classify with certainty. We have obtained optical spectra for thirty of these targets, and are conducting an ongoing observing campaign to fully identify the sample. For sources classified as stellar or active galactic nuclei (AGNs) with certainty, we construct spectral energy distributions (SEDs) using the 2MASS, UBV, and GALEX data supplied for their optical counterparts by the KIC, and show that the SEDs differ qualitatively between the source types, and so can offer a method of classification in absence of a spectrum. Future papers in this series will analyze the timing properties of the stars and AGN in our sample separately. Our survey provides the first X-ray and UV data for a number of known variable stellar sources, as well as a large number of new X-ray detections in this well-studied portion of the sky. The KSwAGS survey is currently ongoing in the K2 ecliptic plane fields