A UBV Photometric Survey of the Kepler Field

TL;DR

This paper details a comprehensive ground-based UBV photometric survey of the Kepler field, significantly expanding the optical data available and identifying hot sources not previously targeted by Kepler.

Contribution

It introduces a new UBV survey covering 191 square degrees with over 4.4 million sources, adding U-band data to the Kepler Input Catalog for the first time.

Findings

Added U-band data reveals hot sources not previously targeted by Kepler.

Survey covers 191 square degrees with over 4.4 million sources.

Enhanced optical coverage improves the characterization of Kepler field objects.

Abstract

We present the motivations for and methods we used to create a new ground-based photometric survey of the field targeted by the NASA Kepler Mission. The survey contains magnitudes for 4414002 sources in one or more of the UBV filters, including 1862902 sources detected in all three filters. The typical completeness limit is U~18.7, B~19.3, and V~19.1 magnitudes, but varies by location. The area covered is 191 square degrees and includes the areas on and between the 42 Kepler CCDs as well as additional areas around the perimeter of the Kepler field. The major significance of this survey is our addition of U to the optical bandpass coverage available in the Kepler Input Catalog, which was primarily limited to the redder SDSS griz and D51 filters. The U coverage reveals a sample of the hottest sources in the field, many of which are not currently targeted by Kepler, but may be objects of astrophysical interest.