Evidence from sub-millimetre observations for thermal dust emission in NGC4151

Most quasars and Seyfert 1 galaxies have spectra that rise from optical wavelengths into the 60–100 μm infrared region, beyond which they must suffer a sharp cutoff indicated by the lack of observed millimetre emission. There is evidence1–4 that the infrared emission receives contributions from both thermal emission by interstellar dust and synchrotron radiation from a compact source. Determining the nature of the infrared emission is thus an important step in understanding the structure of quasars and Seyfert 1 galaxies. We report here observations at 438-μm wavelength of the Seyfert 1 galaxy NGC4151 using the UKT14 bolometer on the James Clerk Maxwell Telescope. We find a 5σ upper limit of 200 mJy in an 11″ aperture. Comparison with an earlier measurement at 155-μm indicates that at least half of the 155-μm flux is due to thermal dust emission. The remainder may be from a synchrotron source which becomes self-absorbed at wavelengths of less than 80 μm

Reverberation mapping of the kepler field agn KA1858+4850

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 Hβ 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 days and τJAVELINdays. The Hβ rms line profile has a width of σline = 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 for the mass of the central black hole and an Eddington ratio of L/L Edd 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

Reverberation mapping of the kepler field agn KA1858+4850

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 Hβ 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 days and τJAVELINdays. The Hβ rms line profile has a width of σline = 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 for the mass of the central black hole and an Eddington ratio of L/L Edd 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

Broad-line reverberation in the Kepler-field Seyfert galaxy Zw 229-015

The Seyfert 1 galaxy Zw 229-015 is among the brightest active galaxies being monitored by the Kepler mission. In order to determine the black hole mass in Zw 229-015 from Hβ reverberation mapping, we have carried out nightly observations with the Kast Spectrograph at the Lick 3 m telescope during the dark runs from 2010 June through December, obtaining 54 spectroscopic observations in total. We have also obtained nightly V-band imaging with the Katzman Automatic Imaging Telescope at Lick Observatory and with the 0.9 m telescope at the Brigham Young University West Mountain Observatory over the same period. We detect strong variability in the source, which exhibited more than a factor of two change in broad Hβ flux. From cross-correlation measurements, we find that the Hβ light curve has a rest-frame lag of 3.86+0.69-0.90 days with respect to the V-band continuum variations. We also measure reverberation lags for Hα and Hγ and find an upper limit to the Hδ lag. Combining the Hβ lag measurement with a broad Hβ width of σline = 1590 ± 47 km s-1 measured from the rms variability spectrum, we obtain a virial estimate of M BH = 1.00+0.19-0.24 × 107 M⊙ for the black hole in Zw 229-015. As a Kepler target, Zw 229-015 will eventually have one of the highest-quality optical light curves ever measured for any active galaxy, and the black hole mass determined from reverberation mapping will serve as a benchmark for testing relationships between black hole mass and continuum variability characteristics in active galactic nuclei. © 2011. The American Astronomical Society. All rights reserved