# Summary of K2 Program GO14071

Title: X-ray Sources in K2  Rigorously Probing Active Galaxy Accretion and Stellar Variability

PI: Boyd, Patricia T. (UMBC and NASA's Goddard Space Flight Center)
CoIs: Mushotzky, Richard; Howell, Steve B; Smith, Krista Lynne

P.I.: P. BoydNASA/GSFC; Co-Is: K.L. SmithNASA/GSFC, UMd, R. MushotzkyUMd, S. HowellNASA/ARC 
 
Scientific Justification 
We request K2 monitoring of unidentified and known X-ray sources in Campaigns 14 through 16, compiled from a variety of sources
 including the Chandra Source Catalog and the Million Quasar Catalog, to probe accretion onto compact objects at a variety of mass
 and time scales. Our KSwAGS survey found 93 bright X-ray sources in the original Kepler FOV (Smith et al., 2015). Approximately
 half were active galaxies while the remainder were active stars of various types (pulsating stars, rapid rotators, close binaries, flaring
 M-stars). A Kepler GO survey (PI: Still) of Chandra point sources resulted in a similar distribution of stars to active galaxies. High
 precision optical follow-up is scientifically useful for all sources; the AGN allow for a study of variability characteristics as a function
 of SMBH mass (Smith et al., 2015) and the stars allow for the study of a variety of rapid rotators and chromospheric activity (Howell
 et al., 2016). We received time for K2 to monitor KSwAGS sources in Fields 4,8 and 11-13. This proposal has identical scientific
 goals and will continue the K2 optical monitoring of X-ray sources, but with target selection criteria that relies on archival X-ray
 observations only and not on new Swift pointings. 
Previous AGN in the original Kepler field were selected using near-infrared photometric methods (e.g., Edelson & Malkan 2012).
 These methods preferentially select AGN with high black hole masses (MBH e 10^8 MSUN), since the method fails if the continuum
 is dominated by starlight rather than AGN light (e.g., Lacy et al. 2004, Stern et al. 2012). Fortunately, X-ray selection uncovers low-
MBH, low luminosity, and low accretion-rate AGN. These types of AGN have predicted variability timescales short enough to be
 constrained by a ~80-day K2 campaign. Indeed, narrow-line Sy 1 objects (NLS1) are expected to vary on timescales of days to weeks.
 This science is complimentary to what we are conducting in the original field with high-MBH objects, since the accretion physics is
 expected to differ between these types of objects (i.e., low-accretion rate objects may have advection dominated accretion flows or
 other scenarios instead of the canonical optically-thick, geometrically-thin accretion disk). This further monitoring will critically
 enhance the sample numbers of K2-monitored AGN discovered using a relatively unbiased selection method. We expect on the order of
 50-100 targets in each Field depending on galactic latitude. 

Methodology and Relevance to NASA Astrophysics Science Goals 
We aim to use K2s impressive photometric precision to detect characteristic variability timescales using Fourier analysis. These
 timescales are the only possible direct observables of AGN accretion physics, which remains an important astrophysical mystery and
 directly addresses NASA Astrophysics goal to "[d]iscover how the universe works, explore how it began and evolved, and search
 for life on planets around other stars.".  Additionally, these X-ray selected targets will fill in the phase-space of black hole mass and
 accretion rate, complementing our work in the original Kepler field.

# Targets requested by this program that have been observed (44)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
248447040, 162.349856, 1.373481, 17.583, GO14088_LC|GO14071_LC|GO14008_LC
248451618, 156.52923, 1.529319, 17.757, GO14016_LC|GO14088_LC|GO14071_LC|GO14008_LC
248489675, 161.083808, 2.805496, 16.561, GO14071_LC|GO14008_LC
248498971, 160.983516, 3.113693, 16.51, GO14071_LC|GO14079_LC
248503559, 160.473361, 3.250149, 16.614, GO14071_LC|GO14008_LC|GO14079_LC
248538486, 160.720665, 4.244764, 16.649, GO14071_LC|GO14008_LC|GO14079_LC
248577113, 156.941012, 5.266325, 17.411, GO14088_LC|GO14071_LC|GO14008_LC
248581626, 157.576173, 5.383961, 17.281, GO14071_LC
248583472, 157.272988, 5.432076, 17.606, GO14071_LC|GO14008_LC|GO14079_LC
248583744, 163.183319, 5.439678, 17.85, GO14088_LC|GO14071_LC|GO14008_LC
248585172, 157.62539, 5.478702, 12.054, GO14071_LC|GO14009_LC|GO14021_LC
248586655, 162.889054, 5.521135, 17.965, GO14088_LC|GO14071_LC|GO14008_LC
248597344, 162.814166, 5.806899, 16.61, GO14071_LC|GO14008_LC|GO14079_LC
248604549, 158.602727, 5.988091, 17.273, GO14071_LC|GO14008_LC|GO14079_LC
248621588, 160.031573, 6.419197, 17.968, GO14088_LC|GO14071_LC|GO14008_LC
248639472, 158.04232, 6.86818, 16.123, GO14071_LC|GO14008_LC|GO14079_LC
248649854, 156.831004, 7.118311, 17.262, GO14088_LC|GO14071_LC|GO14008_LC
248650911, 161.132326, 7.14486, 17.455, GO14088_LC|GO14071_LC|GO14008_LC
248652286, 161.665322, 7.178993, 17.829, GO14071_LC|GO14008_LC
248655925, 161.437552, 7.267765, 17.619, GO14071_LC
248659505, 162.971056, 7.356331, 17.91, GO14088_LC|GO14071_LC|GO14008_LC
248666804, 158.815217, 7.539046, 15.074, GO14071_LC|GO14052_LC
248667381, 156.960652, 7.554417, 17.489, GO14088_LC|GO14071_LC|GO14008_LC
248667886, 158.828078, 7.568421, 16.472, GO14071_LC|GO14008_LC|GO14079_LC
248672544, 157.017376, 7.680815, 17.661, GO14088_LC|GO14071_LC|GO14008_LC
248682847, 160.078185, 7.931566, 17.787, GO14088_LC|GO14071_LC|GO14008_LC
248686223, 158.058082, 8.013484, 17.362, GO14071_LC|GO14079_LC
248694266, 157.406512, 8.203455, 17.815, GO14088_LC|GO14071_LC|GO14008_LC
248717158, 161.271517, 8.727498, 15.772, GO14088_LC|GO14071_LC|GO14008_LC
248735580, 162.228035, 9.14051, 17.887, GO14088_LC|GO14071_LC|GO14008_LC
248736029, 157.909112, 9.15051, 17.484, GO14088_LC|GO14071_LC|GO14008_LC
248770032, 161.80579, 9.953179, 17.84, GO14071_LC|GO14008_LC
248783782, 161.877281, 10.291354, 16.687, GO14071_LC|GO14008_LC
248792841, 162.207991, 10.512063, 17.974, GO14088_LC|GO14071_LC|GO14008_LC
248794974, 159.235182, 10.561792, 17.221, GO14071_LC|GO14008_LC|GO14079_LC
248796086, 160.997637, 10.587297, 17.915, GO14088_LC|GO14071_LC|GO14008_LC
248799490, 161.218346, 10.668266, 17.566, GO14088_LC|GO14071_LC|GO14008_LC
248804650, 159.28823, 10.788514, 17.918, GO14088_LC|GO14071_LC|GO14008_LC
248808886, 160.121579, 10.888346, 16.777, GO14071_LC|GO14008_LC
248839536, 161.121909, 11.636448, 17.609, GO14071_LC
248842175, 160.998088, 11.702894, 17.829, GO14071_LC
248842207, 160.990587, 11.703669, 12.086, GO14071_LC|GO14009_LC|GO14079_LC|GO14065_LC
248843729, 161.026786, 11.742091, 17.819, GO14071_LC
248844091, 161.267621, 11.752432, 15.891, GO14071_LC|GO14008_LC|GO14079_LC