A Search for the Smallest Supermassive Black Holes (2009)
Relations between supermassive black holes (SMBHs) and their host galaxies are now well known, but several questions remain: Do all galaxies harbor SMBHs? Do correlations between BH mass and host...
The Spectral Energy Distributions of Red Two Micron All Sky Survey Active Galactic Nuclei (2009)
Kuraszkiewicz, Joanna, Wilkes, Belinda J., Schmidt, Gary, Ghosh, Himel, Smith, Paul S., Cutri, Roc, ...
We present infrared (IR) to X-ray spectral energy distributions (SEDs) for 44 red active galactic nuclei (AGNs) selected from the Two Micron All Sky Survey (2MASS) survey on the basis of their red J...
The Spectral Energy Distributions of Red 2MASS AGN (2008)
Kuraszkiewicz, Joanna, Wilkes, Belinda J., Schmidt, Gary, Ghosh, Himel, Smith, Paul S., Cutri, Roc, ...
We present infrared (IR) to X-ray spectral energy distributions (SEDs) for 44 red AGN selected from the 2MASS survey on the basis of their red J-K$_S$ color (>2 mag) and later observed by Chandra. In...
Finding Local Low-mass Supermassive Black Holes (2008)
Mathur, Smita, Ghosh, Himel, Ferrarese, Laura, Fiore, Fabrizio
The low-mass end of the supermassive black hole mass function is unknown and difficult to determine. Here we discuss our successful program to find active nuclei of late type "normal" galaxies using...
Detecting Low-Mass Supermassive Black Holes (2008)
Ghosh, Himel, Mathur, Smita, Fiore, Fabrizio, Ferrarese, Laura
We demonstrate the feasibility of uncovering supermassive black holes in late-type, quiescent spiral galaxies by detecting signs of very low-level nuclear activity. We use a combination of x-ray...
Low-Level Nuclear Activity in Nearby Spiral Galaxies (2008)
Ghosh, Himel, Mathur, Smita, Fiore, Fabrizio, Ferrarese, Laura
We are conducting a search for supermassive black holes (SMBHs) with masses below 10^7 M_sun by looking for signs of extremely low-level nuclear activity in nearby galaxies that are not known to be...
NGC 5548 in a Low-Luminosity State: Implications for the Broad-Line Region (2007)
Bentz, Misty C., Denney, Kelly D., Cackett, Edward M., Dietrich, Matthias, Fogel, Jeffrey K. J., Ghosh, Himel, ...
We describe results from a new ground-based monitoring campaign on NGC 5548, the best studied reverberation-mapped AGN. We find that it was in the lowest luminosity state yet recorded during a...
The Mass of the Black Hole in the Seyfert 1 Galaxy NGC 4593 from Reverberation Mapping (2006)
Denney, Kelly D., Bentz, Misty C., Peterson, Bradley M., Pogge, Richard W., Cackett, Edward M., Dietrich, Matthias, ...
We present new observations leading to an improved black hole mass estimate for the Seyfert 1 galaxy NGC 4593 as part of a reverberation-mapping campaign conducted at the MDM Observatory....
A Reverberation-Based Mass for the Central Black Hole in NGC 4151 (2006)
Bentz, Misty C., Denney, Kelly D., Cackett, Edward M., Dietrich, Matthias, Fogel, Jeffrey K. J., Ghosh, Himel, ...
We have undertaken a new ground-based monitoring campaign to improve the estimates of the mass of the central black hole in NGC 4151. We measure the lag time of the broad H beta line response...
Chandra Observations of Candidate "True" Seyfert 2 Nuclei (2006)
Ghosh, Himel, Pogge, Richard W., Mathur, Smita, Martini, Paul, Shields, Joseph C.
The Unification Model for active galactic nuclei posits that Seyfert 2s are intrinsically like Seyfert 1s, but that their broad-line regions (BLRs) are hidden from our view. A Seyfert 2 nucleus that...
Chandra Detection of Highest Redshift (z~6) Quasars in X-rays (2002)
Mathur, Smita, Wilkes, Belinda, Ghosh, Himel
We report on Chandra observations of three quasars SDSSP J083643+005453, SDSSP J103027+052455, and SDSSP J130608+035626 at redshifts 5.82, 6.28 and 5.99 respectively. All the three sources are...
X-ray properties of Red Active Galactic Nuclei (2001)
Wilkes, Belinda J., Schmidt, Gary D., Cutri, Roc M., Ghosh, Himel, Hines, Dean C., Nelson, Brant, ...
The Two Micron All Sky Survey (2MASS) is finding previously unidentified, luminous red active galactic nuclei (AGN). This new sample has a space density similar to, or greater than, previously known...
Engineering nonclassical field states in cavity quantum electrodynamics (1996)
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