Browsing by Subject "monitoring project"

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    Black Hole Mass And Eddington Ratio Distribution Functions Of X-Ray-Selected Broad-Line AGNs At Z Similar To 1.4 In The Subaru XMM-Newton Deep Field
    (2012-12) Nobuta, K.; Akiyama, M.; Ueda, Y.; Watson, M. G.; Silverman, J.; Hiroi, K.; Ohta, K.; Iwamuro, F.; Yabe, K.; Tamura, N.; Moritani, Y.; Sumiyoshi, M.; Takato, N.; Kimura, M.; Maihara, T.; Dalton, G.; Lewis, I.; Bonfield, D.; Lee, H.; Curtis-Lake, E.; Macaulay, E.; Clarke, F.; Sekiguchi, K.; Simpson, C.; Croom, S.; Ouchi, Masami; Hanami, H.; Yamada, T.; Lee, H.
    In order to investigate the growth of supermassive black holes (SMBHs), we construct the black hole mass function (BHMF) and Eddington ratio distribution function (ERDF) of X-ray-selected broad-line active galactic nuclei (AGNs) at z similar to 1.4 in the Subaru XMM-Newton Deep Survey (SXDS) field. A significant part of the accretion growth of SMBHs is thought to take place in this redshift range. Black hole masses of X-ray-selected broad-line AGNs are estimated using the width of the broad Mg II line and 3000 angstrom monochromatic luminosity. We supplement the Mg II FWHM values with the H alpha FWHM obtained from our NIR spectroscopic survey. Using the black hole masses of broad-line AGNs at redshifts between 1.18 and 1.68, the binned broad-line AGN BHMFs and ERDFs are calculated using the V-max method. To properly account for selection effects that impact the binned estimates, we derive the corrected broad-line AGN BHMFs and ERDFs by applying the maximum likelihood method, assuming that the ERDF is constant regardless of the black hole mass. We do not correct for the non-negligible uncertainties in virial BH mass estimates. If we compare the corrected broad-line AGN BHMF with that in the local universe, then the corrected BHMF at z = 1.4 has a higher number density above 10(8) M-circle dot but a lower number density below that mass range. The evolution may be indicative of a downsizing trend of accretion activity among the SMBH population. The evolution of broad-line AGN ERDFs from z = 1.4 to 0 indicates that the fraction of broad-line AGNs with accretion rates close to the Eddington limit is higher at higher redshifts.
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    Reverberation Mapping Of The Kepler Field AGN Ka1858+4850
    (2014-11) Pei, Liuyi; Barth, Aaron J.; Aldering, Greg S.; Briley, Michael M.; Carroll, Carla J.; Carson, Daniel J.; Cenko, S. Bradley; Clubb, Kelsey I.; Cohen, Daniel P.; Cucchiara, Antonino; Desjardins, Tyler D.; Edelson, Rick; Fang, Jerome J.; Fedrow, Joseph M.; Filippenko, Alexei V.; Fox, Ori D.; Furniss, Amy; Gates, Elinor L.; Gregg, Michael; Gustafson, Scott; Horst, J. Chuck; Joner, Michael D.; Kelly, Patrick L.; Lacy, Mark; Laney, C. David; Leonard, Douglas C.; Li, Weidong; Malkan, Matthew A.; Margon, Bruce; Neeleman, Marcel; Nguyen, My L.; Prochaska, J. Xavier; Ross, Nathaniel R.; Sand, David J.; Searcy, Kinchen J.; Shivvers, Isaac S.; Silverman, Jeffrey M.; Smith, Graeme H.; Suzuki, Nao; Smith, Krista Lynne; Tytler, David; Werk, Jessica K.; Worseck, Gabor; Silverman, Jeffrey M.
    KA1858+4850 is a narrow-line Seyfert 1 galaxy at redshift 0.078 and is among the brightest active galaxies monitored by the Kepler mission. We have carried out a reverberation mapping campaign designed to measure the broad-line region size and estimate the mass of the black hole in this galaxy. We obtained 74 epochs of spectroscopic data using the Kast Spectrograph at the Lick 3 m telescope from 2012 February to November, and obtained complementary V-band images from five other ground-based telescopes. We measured the H beta light curve lag with respect to the V-band continuum light curve using both cross-correlation techniques (CCF) and continuum light curve variability modeling with the JAVELIN method and found rest-frame lags of tau(CCF) = 13.53(+2.03)(-2.32) days and tau(JAVELIN) = 13.15(+1.08)(-1.00) days. The H beta rms line profile has a width of sigma line = 770 +/- 49 km s(-1). Combining these two results and assuming a virial scale factor of f = 5.13, we obtained a virial estimate of M-BH = 8.06(+1.59)(-1.72) x 10(6) M circle dot for the mass of the central black hole and an Eddington ratio of L/L-Edd approximate to 0.2. We also obtained consistent but slightly shorter emission-line lags with respect to the Kepler light curve. Thanks to the Kepler mission, the light curve of KA1858+4850 has among the highest cadences and signal-to-noise ratios ever measured for an active galactic nucleus; thus, our black hole mass measurement will serve as a reference point for relations between black hole mass and continuum variability characteristics in active galactic nuclei.