# Summary of K2 Program GO13086

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; Smith, Krista Lynne; Howell, Steve B

X-ray Sources in K2  Rigorously Probing Active Galaxy Accretion and Stellar Variability (K2 Cycle 4 Step-1 Proposal)

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 11 through 13, 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 Field 4, and Field 8. 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 100 targets in Fields 11 and 13, and about 60 in Field 12.

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
210674635, 67.850239, 18.00598, 16.711, GO13117_LC|GO13009_LC|GO13016_LC|GO13002_LC|GO13036_LC|GO13086_LC|GO13082_LC
210678118, 67.774212, 18.055873, 14.734, GO13123_LC|GO13086_LC
210679952, 67.82006, 18.081474, 18.147, GO13086_LC
210683818, 67.891989, 18.134695, 15.04, GO13117_LC|GO13009_LC|GO13002_LC|GO13086_LC|GO13082_LC|GO13119_LC|GO13005_LC
210684392, 67.935195, 18.142094, 18.157, GO13117_LC|GO13009_LC|GO13086_LC
210690598, 67.900561, 18.228685, 17.913, GO13117_LC|GO13009_LC|GO13016_LC|GO13086_LC
210690886, 67.917023, 18.23246, 16.124, GO13086_LC
210690892, 67.916987, 18.23253, 12.012, GO13117_LC|GO13009_LC|GO13016_LC|GO13002_LC|GO13121_LC|GO13086_LC|GO13082_LC|GO13058_LC|GO13119_LC|GO13005_LC|GO13118_LC
210690913, 67.9103, 18.232801, 13.698, GO13117_LC|GO13009_LC|GO13016_LC|GO13086_LC|GO13082_LC|GO13058_LC|GO13005_LC|GO13118_LC|GO13082_SC
210693615, 67.854755, 18.271312, 10.12, GO13049_LC|GO13123_LC|GO13071_LC|GO13122_LC|GO13016_LC|GO13002_LC|GO13086_LC|GO13082_LC|GO13118_LC
210698143, 67.81579, 18.335302, 14.677, GO13117_LC|GO13123_LC|GO13009_LC|GO13016_LC|GO13086_LC|GO13082_LC|GO13118_LC
210698281, 68.060705, 18.337455, 11.961, GO13117_LC|GO13123_LC|GO13009_LC|GO13016_LC|GO13002_LC|GO13086_LC|GO13119_LC|GO13070_LC|GO13118_LC
210699672, 67.990844, 18.358492, 15.847, GO13086_LC
210699801, 67.990804, 18.360528, 12.484, GO13117_LC|GO13071_LC|GO13009_LC|GO13122_LC|GO13016_LC|GO13002_LC|GO13121_LC|GO13086_LC|GO13082_LC|GO13058_LC|GO13119_LC|GO13118_LC
210756090, 65.786027, 19.202026, 11.277, GO13049_LC|GO13086_LC|GO13902_LC|GO13903_LC|GO13904_LC
246872443, 69.131623, 16.484998, 11.99, GO13071_LC|GO13086_LC
246878254, 69.000375, 16.540775, 10.235, GO13008_LC|GO13049_LC|GO13064_LC|GO13123_LC|GO13002_LC|GO13023_LC|GO13077_LC|GO13039_LC|GO13086_LC|GO13090_LC
246884034, 69.148015, 16.597771, 18.25, GO13086_LC
247030920, 68.386719, 18.012114, 13.096, GO13117_LC|GO13086_LC|GO13118_LC
247031423, 68.387705, 18.016719, 7.047, GO13117_LC|GO13016_LC|GO13002_LC|GO13086_LC|GO13052_LC|GO13019_LC|GO13127_LC
247031436, 68.386812, 18.016826, 7.028, GO13086_LC|GO13019_LC
247032616, 68.066001, 18.027437, 11.259, GO13117_LC|GO13009_LC|GO13016_LC|GO13086_LC|GO13119_LC
247034456, 68.652511, 18.045832, 17.494, GO13086_LC
247034775, 68.182246, 18.048977, 12.444, GO13117_LC|GO13009_LC|GO13016_LC|GO13002_LC|GO13086_LC|GO13082_LC|GO13118_LC
247035365, 68.470205, 18.054601, 14.416, GO13008_LC|GO13086_LC
247045617, 68.423499, 18.152203, 14.951, GO13086_LC
247047380, 68.45305, 18.169436, 13.223, GO13117_LC|GO13009_LC|GO13016_LC|GO13062_LC|GO13086_LC|GO13082_LC|GO13058_LC|GO13119_LC|GO13118_LC
247051861, 68.066961, 18.212874, 12.687, GO13117_LC|GO13029_LC|GO13123_LC|GO13022_LC|GO13009_LC|GO13016_LC|GO13042_LC|GO13086_LC|GO13082_LC|GO13118_LC|GO13042_SC
247272256, 74.235007, 20.301132, 15.932, GO13086_LC
247276079, 74.313518, 20.335041, 16.749, GO13086_LC
247285516, 71.966463, 20.421499, 17.328, GO13001_LC|GO13086_LC
247305762, 74.20972, 20.602286, 13.925, GO13049_LC|GO13018_LC|GO13086_LC
247308468, 72.569463, 20.62584, 13.844, GO13008_LC|GO13064_LC|GO13123_LC|GO13018_LC|GO13023_LC|GO13077_LC|GO13086_LC|GO13073_LC|GO13090_LC
247431982, 72.723261, 21.656531, 13.711, GO13117_LC|GO13123_LC|GO13009_LC|GO13016_LC|GO13086_LC
247436671, 72.836133, 21.694543, 16.081, GO13086_LC
247820507, 67.348912, 24.549997, 13.069, GO13117_LC|GO13009_LC|GO13011_LC|GO13016_LC|GO13002_LC|GO13121_LC|GO13086_LC|GO13082_LC|GO13119_LC|GO13005_LC
247827638, 67.400276, 24.598793, 12.443, GO13117_LC|GO13009_LC|GO13016_LC|GO13086_LC|GO13082_LC
247850643, 66.618999, 24.756508, 15.353, GO13086_LC
247925750, 75.743699, 25.273739, 18.583, GO13086_LC
248006676, 70.206289, 25.855259, 12.416, GO13117_LC|GO13009_LC|GO13016_LC|GO13002_LC|GO13086_LC|GO13082_LC
248029954, 69.947849, 26.027994, 18.808, GO13117_LC|GO13009_LC|GO13011_LC|GO13042_LC|GO13002_LC|GO13086_LC
248030407, 69.937014, 26.03133, 15.896, GO13117_LC|GO13009_LC|GO13011_LC|GO13016_LC|GO13002_LC|GO13086_LC|GO13082_LC
248038058, 70.033342, 26.090384, 13.788, GO13117_LC|GO13009_LC|GO13002_LC|GO13086_LC|GO13119_LC
248055184, 68.478154, 26.224363, 13.493, GO13117_LC|GO13009_LC|GO13016_LC|GO13002_LC|GO13121_LC|GO13086_LC|GO13082_LC|GO13119_LC