Estimating Black Hole Masses in Active Galactic Nuclei Using the MgII 2800 Emission Line (2009)
Wang, Jian-Guo, Dong, Xiao-Bo, Wang, Ting-Gui, Ho, Luis C., Yuan, Weimin, Wang, Huiyuan, ...
We investigate the relationship between the linewidths of broad Mg II \lambda2800 and Hbeta in active galactic nuclei (AGNs) to refine them as tools to estimate black hole (BH) masses. We perform a...
Active Galaxies and the Study of Black Hole Demographics (2009)
We discuss the critical importance of black hole mass indicators based on scaling relations in active galaxies. We highlight outstanding uncertainties in these methods and potential paths to...
Magellan Spectroscopy of Low-Redshift Active Galactic Nuclei (2009)
We present an atlas of moderate-resolution (R ~ 1200-1600) optical spectra of 94 low-redshift (z < 0.5) active galactic nuclei taken with the Magellan 6.5 m Clay Telescope. The spectra mostly cover...
On the Disappearance of the Broad-Line Region in Low-Luminosity Agns (2009)
The disk-wind scenario for the broad-line region (BLR) and toroidal obscuration in active galactic nuclei predicts the disappearance of the BLR at low luminosities. In accordance with the model...
The Growth of Black Holes: Insights From Obscured Active Galaxies (2009)
Greene, Jenny E., Zakamska, Nadia L., Liu, Xin, Barth, Aaron J., Ho, Luis C.
Obscured or narrow-line active galaxies offer an unobstructed view of the quasar environment in the presence of a luminous and vigorously accreting black hole. We exploit the large new sample of...
Ho, Luis C., Greene, Jenny E., Filippenko, Alexei V., Sargent, Wallace L. W.
We present new central stellar velocity dispersion measurements for 428 galaxies in the Palomar spectroscopic survey of bright, northern galaxies. Of these, 142 have no previously published...
Origin and Dynamical Support of Ionized Gas in Galaxy Bulges (2009)
We combine ionized gas ([N II] 6583) and stellar central velocity dispersions for a sample of 345 galaxies, with and without active galactic nuclei (AGNs), to study the dynamical state of the nuclear...
Radiatively Inefficient Accretion in Nearby Galaxies (2009)
We use new central stellar velocity dispersions and nuclear X-ray and Halpha luminosities for the Palomar survey of nearby galaxies to investigate the distribution of nuclear bolometric luminosities...
Ho, Luis C., Greene, Jenny E., Filippenko, Alexei V., Sargent, Wallace L. W.
We present new central stellar velocity dispersion measurements for 428 galaxies in the Palomar spectroscopic survey of bright, northern galaxies. Of these, 142 have no previously published...
Gultekin, Kayhan, Richstone, Douglas O., Gebhardt, Karl, Lauer, Tod R., Tremaine, Scott, Aller, M. C., ...
We derive improved versions of the relations between supermassive black hole mass (M_BH) and host-galaxy bulge velocity dispersion (sigma) and luminosity (L) (the M-sigma and M-L relations), based on...
Desroches, Louis-Benoit, Greene, Jenny E., Ho, Luis C.
We present X-ray properties of optically-selected intermediate-mass (~10^5--10^6 M_Sun) black holes (BHs) in active galaxies (AGNs), using data from the Chandra X-Ray Observatory. Our observations...
Revisiting the "Fundamental Plane" of Black Hole Activity at Extremely Low Luminosities (2009)
Yuan, Feng, Yu, Zhaolong, Ho, Luis C.
We investigate the origin of the X-ray emission in low-luminosity AGNs (LLAGNs). Yuan & Cui (2005) predicted that the X-ray emission should originate from jets rather than from an advection-dominated...
A Quintet of Black Hole Mass Determinations (2009)
Gultekin, Kayhan, Richstone, Douglas O., Gebhardt, Karl, Lauer, Tod R., Pinkney, Jason, Aller, M. C., ...
We report five new measurements of central black hole masses based on STIS and WFPC2 observations with the Hubble Space Telescope and on axisymmetric, three-integral, Schwarzschild orbit-library...
A Magnetohydrodynamic Model for the Formation of Episodic Jets (2008)
Yuan, Feng, Lin, Jun, Wu, Kinwah, Ho, Luis C.
Episodic ejection of plasma blobs have been observed in many black hole systems. While steady, continuous jets are believed to be associated with large-scale open magnetic fields, what causes the...
Greene, Jenny E., Ho, Luis C., Barth, Aaron J.
We investigate the relationship between black hole mass and host galaxy properties for active galaxies with the lowest black hole masses currently known in galaxy nuclei. Hubble Space Telescope...
Walsh, Jonelle L., Barth, Aaron J., Ho, Luis C., Filippenko, Alexei V., Rix, Hans-Walter, Shields, Joseph C., ...
We present Space Telescope Imaging Spectrograph observations of 14 nearby low-luminosity active galactic nuclei, including 13 LINERs and 1 Seyfert, taken at multiple parallel slit positions centered...
A Stellar Dynamical Measurement of the Black Hole Mass in the Maser Galaxy NGC 4258 (2008)
Siopis, Christos, Gebhardt, Karl, Lauer, Tod R., Kormendy, John, Pinkney, Jason, Richstone, Douglas, ...
We determine the mass of the black hole at the center of the spiral galaxy NGC 4258 by constructing axisymmetric dynamical models of the galaxy. These models are constrained by high spatial...
Caught in formation: the nuclear-cluster-to-be in NGC 2139 (2008)
Andersen, David R., Walcher, C. Jakob, Boeker, Torsten, Ho, Luis C., Van Der Marel, Roeland P., Rix, Hans-Walter, ...
Close to its center, the bulgeless galaxy NGC 2139 hosts a star cluster that is younger and less massive than any actual nuclear star cluster (NC) studied so far. We have measured the H-alpha...
Walsh, Jonelle L., Barth, Aaron J., Ho, Luis C., Filippenko, Alexei V., Rix, Hans-Walter, Shields, Joseph C., ...
(Abridged) We present STIS observations of 14 nearby low-luminosity active galactic nuclei, including 13 LINERs and 1 Seyfert, taken at multiple parallel slit positions centered on the galaxy nuclei...
Hu, Chen, Wang, Jian-Min, Ho, Luis C., Chen, Yan-Mei, Zhang, Hao-Tong, Bian, Wei-Hao, ...
Broad Fe II emission is a prominent feature of the optical and ultraviolet spectra of quasars. We report on a systematical investigation of optical Fe II emission in a large sample of 4037 z < 0.8...
Hbeta Profiles in Quasars: Evidence for an Intermediate-line Region (2008)
Hu, Chen, Wang, Jian-Min, Ho, Luis C., Chen, Yan-Mei, Bian, Wei-Hao, Xue, Sui-Jian
We report on a systematic investigation of the Hbeta and Fe II emission lines in a sample of 568 quasars within z < 0.8 selected from the Sloan Digital Sky Survey. The conventional broad Hbeta...
Kim, Minjin, Ho, Luis C., Peng, Chien Y., Barth, Aaron J., Im, Myungshin
Investigating the link between supermassive black hole and galaxy evolution requires careful measurements of the properties of the host galaxies. We perform simulations to test the reliability of a...
Kim, Minjin, Ho, Luis C., Peng, Chien Y., Barth, Aaron J., Im, Myungshin, Martini, Paul, ...
We investigate the origin of the intrinsic scatter in the correlation between black hole mass (MBH) and bulge luminosity [L(bulge)] in a sample of 45 massive, local (z < 0.35) type~1 active galactic...
Zhang, Yu, Gu, Qiusheng, Ho, Luis C.
We study the stellar and dust properties of a well-defined sample of local elliptical galaxies to investigate the relationship between host galaxy properties and nuclear activity. We select a...
An Accreting Black Hole in the Nuclear Star Cluster of the Bulgeless Galaxy NGC 1042 (2008)
Shields, Joseph C., Walcher, C. Jakob, Boeker, Torsten, Ho, Luis C., Rix, Hans-Walter, Van Der Marel, Roeland P.
We present spectroscopic evidence for a low-luminosity, low-excitation active galactic nucleus (AGN) in NGC 1042, powered by an intermediate-mass black hole. These findings are significant in that...
Nuclear Activity in Nearby Galaxies (2008)
A significant fraction of nearby galaxies show evidence of weak nuclear activity unrelated to normal stellar processes. Recent high-resolution, multiwavelength observations indicate that the bulk of...
Properties of Active Galaxies Deduced from H I Observations (2008)
Ho, Luis C., Darling, Jeremy, Greene, Jenny E.
We completed a new survey for H I emission for a large, well-defined sample of 154 nearby (z < 0.1) galaxies with type 1 AGNs. We make use of the extensive database presented in a companion paper to...
A New H I Survey of Active Galaxies (2008)
Ho, Luis C., Darling, Jeremy, Greene, Jenny E.
We have conducted a new Arecibo survey for H I emission for 113 galaxies with broad-line (type 1) active galactic nuclei (AGNs) out to recession velocities as high as 35,000 km/s. The primary aim of...
Walsh, Jonelle L., Barth, Aaron J., Ho, Luis C., Filippenko, Alexei V., Rix, Hans-Walter, Shields, Joseph C., ...
We present Space Telescope Imaging Spectrograph observations of 14 nearby low-luminosity active galactic nuclei, including 13 LINERs and 1 Seyfert, taken at multiple parallel slit positions centered...
An accreting black hole in the nuclear star cluster of the bulgeless galaxy NGC 1042 (2008)
Shields, Joseph C., Walcher, C. Jakob, Böker, Torsten, Ho, Luis C., Rix, Hans-Walter, Van Der Marel, Roeland P.
We present spectroscopic evidence for a low-luminosity, low-excitation active galactic nucleus (AGN) in NGC 1042, powered by an intermediate-mass black hole. These findings are significant in that...
Caught in formation: The nuclear-cluster-to-Be in NGC 2139 (2008)
Andersen, David R., Walcher, C. Jakob, Böker, Torsten, Ho, Luis C., Van Der Marel, Roeland P., Rix, Hans-Walter, ...
Close to its center, the bulgeless galaxy NGC 2139 hosts a star cluster that is younger and less massive than any nuclear star cluster (NC) studied so far. We have measured the Halpha velocity field...
Neil M. Nagar, Heino Falcke, Andrew S. Wilson, Luis C. Ho
We report a high resolution (0: 00 2), 15 GHz survey of a sample of 48 low-luminosity active galactic nuclei with the Very Large Array 1 . Compact radio emission has been detected above a flux...
A supermassive binary black hole with triple disks (2007)
Hayasaki, Kimitake, Mineshige, Shin, Ho, Luis C.
Hierarchical structure formation inevitably leads to the formation of supermassive binary black holes (BBHs) with a sub-parsec separation in galactic nuclei. However, to date there has been no...
The CO Tully-Fisher Relation and Implications for the Host Galaxies of High-Redshift Quasars (2007)
The integrated line width derived from CO spectroscopy provides a powerful tool to study the internal kinematics of extragalactic objects, including quasars at high redshift, provided that the...
A New Sample of Low-mass Black Holes in Active Galaxies (2007)
We present an expanded sample of low-mass black holes (BHs) found in galactic nuclei. Using standard virial mass techniques to estimate BH masses, we select from the Fourth Data Release of the Sloan...
Bulge and Halo Kinematics Across the Hubble Sequence (2007)
The correlation between the maximum rotational velocity of the disk (v_m) and the central stellar velocity dispersion of the bulge (sigma) offers insights into the relationship between the halo and...
The radio properties of type II quasars (2007)
Quasars (of type I) are the luminous analogs of type I Seyfert galaxies. Within the framework of unified models of active galaxies, the population of quasars of type II recently discovered with the...
Gravitational Stability of Circumnuclear Disks in Elliptical Galaxies (2007)
Kawata, Daisuke, Cen, Renyue, Ho, Luis C.
A significant fraction of nearby elliptical galaxies are known to have high density gas disks in their circumnuclear (CN) region (0.1 to a few kpc). Yet, ellipticals, especially luminous ones, show...
The Mass Function of Active Black Holes in the Local Universe (2007)
We present the first measurement of the black hole (BH) mass function for broad-line active galaxies in the local Universe. Using the ~9000 broad-line active galaxies from the Fourth Data Release of...
Radio Emission from the Intermediate-mass Black Hole in the Globular Cluster G1 (2007)
Ulvestad, James S., Greene, Jenny E., Ho, Luis C.
We have used the Very Large Array (VLA) to search for radio emission from the globular cluster G1 (Mayall-II) in M31. G1 has been reported by Gebhardt et al. to contain an intermediate-mass black...
Fe K Line Profile in Low-redshift Quasars: Average Shape and Eddington Ratio Dependence (2007)
Inoue, Hirohiko, Terashima, Yuichi, Ho, Luis C.
We analyze X-ray spectra of 43 Palomar-Green quasars observed with {\it XMM-Newton} in order to investigate their mean Fe K line profile and its dependence on physical properties. The continuum...
Nuclear Star Clusters (Nuclei) in Spiral Galaxies and Connection to Supermassive Black Holes (2007)
Van Der Marel, Roeland P., Rossa, Joern, Walcher, Carl Jakob, Boeker, Torsten, Ho, Luis C., Rix, Hans-Walter, ...
HST observations have revealed that compact sources exist at the centers of many, maybe even most, galaxies across the Hubble sequence. These sources are called "nuclei" or also "nuclear star...
Gravitational stability of circumnuclear disks in elliptical galaxies (2007)
Kawata, Daisuke, Cen, Renyue, Ho, Luis C.
A significant fraction of nearby elliptical galaxies are known to have high-density gas disks in their circumnuclear (CN) region (0.1 to a few kpc). Yet ellipticals, especially luminous ones, show...
Shields, Joseph C., Rix, Hans-Walter, Sarzi, Marc, Barth, Aaron J., Filippenko, Alexei V., Ho, Luis C., ...
We present results from a program of optical spectroscopy for 23 nearby galaxies with emission-line nuclei. This investigation takes advantage of the spatial resolution of the Hubble Space Telescope...
Nuclear star custers (nuclei) in spiral galaxies and connection to supermassive black holes (2007)
Van Der Marel, Roeland P., Rossa, Joern, Walcher, Carl Jakob, Boeker, Torsten, Ho, Luis C., Rix, Hans-Walter, ...
HST observations have revealed that compact sources exist at the centers of many, maybe even most, galaxies across the Hubble sequence. These sources are called "nuclei" or also "nuclear star...
Gravitational stability of circumnuclear disks in elliptical galaxies (2007)
Kawata, Daisuke, Cen, Renyue, Ho, Luis C.
A significant fraction of nearby elliptical galaxies are known to have high-density gas disks in their circumnuclear (CN) region (0.1 to a few kpc). Yet ellipticals, especially luminous ones, show...
Gravitational stability of circumnuclear disks in elliptical galaxies (2007)
Kawata, Daisuke, Cen, Renyue, Ho, Luis C.
A significant fraction of nearby elliptical galaxies are known to have high-density gas disks in their circumnuclear (CN) region (0.1 to a few kpc). Yet ellipticals, especially luminous ones, show...
Gravitational stability of circumnuclear disks in elliptical galaxies (2007)
Kawata, Daisuke, Cen, Renyue, Ho, Luis C.
A significant fraction of nearby elliptical galaxies are known to have high-density gas disks in their circumnuclear (CN) region (0.1 to a few kpc). Yet ellipticals, especially luminous ones, show...
Gravitational stability of circumnuclear disks in elliptical galaxies (2007)
Kawata, Daisuke, Cen, Renyue, Ho, Luis C.
A significant fraction of nearby elliptical galaxies are known to have high-density gas disks in their circumnuclear (CN) region (0.1 to a few kpc). Yet ellipticals, especially luminous ones, show...
The fine-structure lines of singly ([Ne II] 12.8 micron) and doubly ([Ne III] 15.6 micron) ionized neon are among the most prominent features in the mid-infrared spectra of star-forming regions, and...
The Host Galaxy of the Quasar HE 0450-2958 (2006)
Kim, Minjin, Ho, Luis C., Peng, Chien Y., Im, Myungshin
A recent study suggests that the quasar HE 0450-2958 is hosted by a galaxy substantially fainter than that inferred from the correlation between black hole mass and bulge luminosity. As this result...
The Centers of Early-Type Galaxies with HST. VI. Bimodal Central Surface Brightness Profiles (2006)
Lauer, Tod R., Gebhardt, Karl, Faber, S. M., Richstone, Douglas, Tremaine, Scott, Kormendy, John, ...
We combine the results from several HST investigations of the central structure of early-type galaxies to generate a large sample of parameterized surface photometry. The studies included were those...
Cao, Chen, Wu, Hong, Wang, Zhong, Ho, Luis C., Huang, Jiasheng, Deng, Zugan
A large position angle misalignment between the stellar bar and the distribution of dust in the late-type barred spiral NGC 3488 was discovered, using mid-infrared images from the Spitzer Space...
X-ray Properties of Intermediate-mass Black Holes in Active Galaxies (2006)
We present a pilot study of the X-ray properties of intermediate-mass (~10^5-10^6 M_sun) black holes in active galaxies using the Chandra X-ray telescope. Eight of the 10 active galaxies are detected...
Lauer, Tod R., Faber, S. M., Richstone, Douglas, Gebhardt, Karl, Tremaine, Scott, Postman, Marc, ...
Black hole masses predicted from the Mbh-sigma relationship conflict with those predicted from the Mbh-L relationship for the most luminous galaxies, such as brightest cluster galaxies (BCGs). This...
Desroches, Louis-Benoit, Filippenko, Alexei V., Kaspi, Shai, Laor, Ari, Maoz, Dan, Ganeshalingam, Mohan, ...
We present optical observations of the low-luminosity Seyfert 1 nucleus of NGC 4395, as part of a multiwavelength reverberation-mapping program. Observations were carried out over two nights in 2004...
Stellar populations in the nuclei of late-type spiral galaxies (2006)
Walcher, Carl-Jakob, Boeker, Torsten, Charlot, Stephane, Ho, Luis C., Rix, Hans-Walter, Rossa, Joern, ...
(Abridged) As part of an ongoing effort to study the stellar nuclei of very late-type, bulge-less spirals, we present results from a high-resolution spectroscopic survey of nine such nuclear star...
Rossa, Joern, Van Der Marel, Roeland P., Boeker, Torsten, Gerssen, Joris, Ho, Luis C., Rix, Hans-Walter, ...
(Abridged) We study the nuclear star clusters in spiral galaxies of various Hubble types using spectra obtained with STIS on-board HST. We observed the nuclear clusters in 40 galaxies, selected from...
Evidence for Rapidly Spinning Black Holes in Quasars (2006)
Wang, Jian-Min, Chen, Yan-Mei, Ho, Luis C., McLure, Ross J.
It has long been believed that accretion onto supermassive black holes powers quasars, but there has been relatively few observational constraints on the spins of the black holes. We address this...
Seigar, Marc S., Bullock, James S., Barth, Aaron J., Ho, Luis C.
We investigate the use of spiral arm pitch angles as a probe of disk galaxy mass profiles. We confirm our previous result that spiral arm pitch angles (P) are well-correlated with the rate of shear...
O'Neill, Paul M., Kaspi, Shai, Laor, Ari, Nandra, Kirpal, Moran, Edward C., Peterson, Bradley M., ...
We report on two Chandra observations, and a simultaneous Hubble Space Telescope ultraviolet observation, of the dwarf Seyfert 1 galaxy NGC 4395. Each Chandra observation had a duration of ~30 ks,...
Contribution of Stellar Tidal Disruptions to the X-Ray Luminosity Function of Active Galaxies (2006)
Milosavljevic, Milos, Merritt, David, Ho, Luis C.
The luminosity function of active galactic nuclei has been measured down to luminosities ~10^{42} erg/s in the soft and hard X-rays. Some fraction of this activity is associated with the accretion of...
Constraints on the Star Formation Rate in Active Galaxies (2006)
Kim, Minjin, Ho, Luis C., Im, Myungshin
The [O II] 3727 emission line is often used as an indicator of star formation rate in extragalactic surveys, and it can be an equally effective tracer of star formation in systems containing luminous...
Rossa, Jörn, Van Der Marel, Roeland P., Böker, Torsten, Gerssen, Joris, Ho, Luis C., Rix, Hans-Walter, ...
We study the nuclear star clusters (NCs) in spiral galaxies of various Hubble types using spectra obtained with the STIS on board the Hubble Space Telescope (HST). We observed the nuclear clusters in...
Probing the coevolution of supermassive black holes and quasar host galaxies (2006)
Peng, Chien Y., Impey, Chris D., Ho, Luis C., Barton, Elizabeth J., Rix, Hans-Walter
At low redshift, there are fundamental correlations between the mass of supermassive black holes (MBH) and the mass (Mbulge) and luminosity of the host galaxy bulge. We investigate the same relation...
The M-sigma Relation in Local Active Galaxies (2005)
We examine whether active galaxies obey the same relation between black hole mass and stellar velocity dispersion as inactive systems, using the largest published sample of velocity dispersions for...
Measuring Stellar Velocity Dispersions in Active Galaxies (2005)
(ABRIDGED) We present stellar velocity dispersion (sigma*) measurements for a significant sample of 40 broad-line (Type 1) active galaxies for use in testing the well-known relation between black...
AGNs and Starbursts: What Is the Real Connection? (2005)
It is now widely believed that the growth of massive black holes is closely linked to the formation of galaxies, but there have been few concrete constraints on the actual physical processes...
Probing the Coevolution of Supermassive Black Holes and Quasar Host Galaxies (2005)
Peng, Chien Y., Impey, Chris D., Ho, Luis C., Barton, Elizabeth J., Rix, Hans-Walter
At low redshift, there are fundamental correlations between the mass of supermassive black holes (MBH) and the mass (Mbulge) and luminosity of the host galaxy bulge. We investigate the same relation...
The Radio Quiescence of Active Galaxies with High Accretion Rates (2005)
Greene, Jenny E., Ho, Luis C., Ulvestad, James S.
We present 6 cm Very Large Array observations of the Greene & Ho (2004) sample of 19 low-mass active galaxies with high accretion rates. This is one of the only studies of a uniform sample of...
Laor, Ari, Barth, Aaron J., Ho, Luis C., Filippenko, Alexei V.
The origin and configuration of the gas which emits broad lines in Type I active galactic nuclei is not established yet. The lack of small-scale structure in the broad emission-line profiles is...
M82, Starbursts, Star Clusters, and the Formation of Globular Clusters (2005)
Keto, Eric, Ho, Luis C., Lo, K. Y.
We observed the nearby starburst galaxy M82 in CO in the higher frequency (2--1) transition to achieve an angular resolution below 1 arc second or 17 pc at the target. We resolved the molecular gas...
Estimating Black Hole Masses in Active Galaxies Using the Halpha Emission Line (2005)
It has been established that virial masses for black holes in low-redshift active galaxies can be estimated from measurements of the optical continuum strength and the width of the broad Hbeta line....
Seigar, Marc S., Barth, Aaron J., Bullock, James, Ho, Luis C.
Recently, it has been shown that a correlation exists between the rate of shear and the spiral arm pitch angle in disk galaxies. The rate of shear depends upon the shape of the rotation curve, which...
Gebhardt, Karl, Rich, R. Michael, Ho, Luis C.
We present dynamical models for the massive globular cluster G1. The goal is to measure or place a significant upper limit on the mass of any central black hole. Whether or not globular clusters...
Peterson, Bradley M., Bentz, Misty C., Desroches, Louis-Benoit, Filippenko, Alexei V., Ho, Luis C., Kaspi, Shai, ...
A reverberation-mapping program on NGC 4395, the least-luminous known Seyfert 1 galaxy, undertaken with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, yields a measurement of...
[O II] Emission in Quasar Host Galaxies: Evidence for a Suppressed Star Formation Efficiency (2005)
The [O II] 3727 line, a commonly used estimator of star formation rate in extragalactic surveys, should be an equally effective tracer of star formation in the host galaxies of quasars, whose...
"Low-state" Black Hole Accretion in Nearby Galaxies (2005)
I summarize the main observational properties of low-luminosity AGNs in nearby galaxies to argue that they are the high-mass analogs of black hole X-ray binaries in the "low/hard" state. The...
The Afterglows of Ultraluminous Quasars (2005)
Wang, Jian-Min, Yuan, Ye-Fei, Ho, Luis C.
Quasars represent a brief phase in the life-cycle of most massive galaxies, but the evolutionary connection between central black holes and their host galaxies remains unclear. While quasars are...
A Comparison of Stellar and Gaseous Kinematics in the Nuclei of Active Galaxies (2005)
To investigate the relationship between black holes and their host galaxies, many groups have used the width of the [O III] 5007 line as a substitute for the stellar velocity dispersion (sigma*) of...
Extreme X-ray Behavior of the Low-Luminosity Active Nucleus in NGC 4395 (2005)
Moran, Edward C., Eracleous, Michael, Leighly, Karen M., Chartas, George, Filippenko, Alexei V., Ho, Luis C., ...
We present the results of a 17 ks Chandra ACIS-S observation of the nearby dwarf spiral galaxy NGC 4395. Chandra affords the first high-quality, broadband X-ray detection of the active nucleus of...
The stellar populations in the central parsecs of galactic bulges (2005)
Sarzi, Marc, Rix, Hans-Walter, Shields, Joseph C., Ho, Luis C., Barth, Aaron J., Rudnick, Gregory, ...
The stellar populations in the central Parsecs of galactic bulges (2005)
Sarzi, Marc, Rix, Hans-Walter, Shields, Joseph C., Ho, Luis C., Barth, Aaron J., Rudnick, Gregory, ...
We present Hubble Space Telescope blue spectra at intermediate spectral resolution for the nuclei of 23 nearby disk galaxies. These objects were selected to have nebular emission in their nuclei and...
The Connection Between Jets, Accretion Disks, and Black Hole Mass in Blazars (2004)
Wang, Jian-Min, Luo, Bin, Ho, Luis C.
The properties of relativistic radio jets are thought to be closely connected with the properties of accretion disks in active galactic nuclei. We explore this issue using a sample of 35 blazars with...
The Centers of Early-Type Galaxies with HST. V. New WFPC2 Photometry (2004)
Lauer, Tod R., Faber, S. M., Gebhardt, Karl, Richstone, Douglas, Tremaine, Scott, Ajhar, Edward A., ...
We analyze HST+WFPC2 images of 77 early-type galaxies. Brightness profiles are classed into "core" or "power-law" forms. Cores are typically rounder than power-law galaxies. Nearly all power-laws...
Shields, Joseph C., Rix, Hans-Walter, Sarzi, Marc, Barth, Aaron J., Filippenko, Alexei V., Ho, Luis C., ...
We present results from a program of optical spectroscopy for 23 nearby galaxy emission-line nuclei. This investigation takes advantage of the spatial resolution of the Hubble Space Telescope to...
The Stellar Populations in the Central Parsecs of Galactic Bulges Central Stellar Populations (2004)
Sarzi, Marc, Rix, Hans-Walter, Shields, Joseph C., Ho, Luis C., Barth, Aaron J., Rudnick, Gregory, ...
We present Hubble Space Telescope blue spectra at intermediate spectral resolution for the nuclei of 23 nearby disk galaxies. These objects were selected to have nebular emission in their nuclei, and...
Active Galactic Nuclei with Candidate Intermediate-Mass Black Holes (2004)
We present an initial sample of 19 intermediate-mass black hole candidates in active galactic nuclei culled from the First Data Release of the Sloan Digital Sky Survey. Using the...
A Population of Massive Globular Clusters in NGC 5128 (2004)
We present velocity dispersion measurements of 14 globular clusters in NGC 5128 (Centarus A) obtained with the MIKE echelle spectrograph on the 6.5m Magellan Clay telescope. These clusters are among...
Black Hole Mass Determinations From Orbit Superposition Models are Reliable (2004)
Richstone, Douglas, Gebhardt, Karl, Aller, Monique, Bender, Ralf, Bower, Gary, Dressler, Alan, ...
We show that orbit-superposition dynamical models (Schwarzschild's method) provide reliable estimates of nuclear black hole masses and errors when constructed from adequate orbit libraries and...
The Carnegie Observatories Astrophysics Series (2004)
On the occasion of the Centennial of the Carnegie Institution of Washington, Carnegie Observatories held a series of four astrophysics symposia in Pasadena from October 2002 to February 2003. The...
Black Hole Demography from Nearby Active Galactic Nuclei (2004)
A significant fraction of local galaxies show evidence of nuclear activity. I argue that the bulk of this activity, while energetically not remarkable, derives from accretion onto a central massive...
What Can We Learn from Nearby AGNs? (2004)
This contribution reviews the properties of nuclear activity in nearby galaxies, with emphasis on their implications for the demography of nuclear black holes and the nature of accretion flows in the...
Böker, Torsten, Sarzi, Marc, McLaughlin, Dean E., Van Der Marel, Roeland P., Rix, Hans-Walter, Ho, Luis C., ...
We investigate the structural properties of nuclear star clusters in late-type spiral galaxies. More specifically, we fit analytical models to Hubble Space Telescope images of 39 nuclear clusters in...
Low-Luminosity AGNs at the Highest Resolution: Jets or Accretion Flows? (2003)
Anderson, James M., Ulvestad, James S., Ho, Luis C.
Six low-luminosity active galactic nuclei have been imaged at multiple frequencies from 1.7--43 GHz (2.3--15 GHz for three of the galaxies) using the Very Long Baseline Array. In spite of dynamic...
Deep Photometry in a Remote M31 Major Axis Field Near G1 (2003)
Rich, R. Michael, Reitzel, David B., Guhathakurta, Puragra, Gebhardt, Karl, Ho, Luis C.
We present photometry from Hubble Space Telescope (HST)/Wide Field Planetary Camera 2 parallel imagery of a remote M31 field at a projected distance of about 34 kpc from the nucleus near the SW major...
The Central Engines of Radio-Loud Quasars (2003)
Wang, Jian-Min, Ho, Luis C., Staubert, Ruediger
We have assembled a sample of 37 RLQs that have been imaged with the HST in order to investigate their black hole masses, accretion rates, and the structure of their accretion disks. The black hole...
Kinematics of Ten Early-Type Galaxies from HST and Ground-Based Spectroscopy (2003)
Pinkney, Jason, Gebhardt, Karl, Bender, Ralf, Bower, Gary, Dressler, Alan, Faber, S. M., ...
We present stellar kinematics for a sample of 10 early-type galaxies observed using the STIS aboard the Hubble Space Telescope, and the Modular Spectrograph on the MDM Observatory 2.4-m telescope....
A Low-Mass Central Black Hole in the Bulgeless Seyfert 1 Galaxy NGC 4395 (2003)
Filippenko, Alexei V., Ho, Luis C.
NGC 4395 is one of the least luminous and nearest known type 1 Seyfert galaxies, and it also lacks a bulge. We present an HST I-band image of its nuclear region and Keck high-resolution (8 km/s)...
The Central Engines of Low-Luminosity AGNs (2003)
I summarize the main characteristics of AGNs in nearby galaxies and present a physical picture of their central engines.
Detection of the "Active" Nucleus of M32 (2003)
Ho, Luis C., Terashima, Yuichi, Ulvestad, James S.
M32 hosts a 2.5x10^6 solar mass central black hole, but signs of nuclear activity in this galaxy have long eluded detection. We report the first conclusive detection of the nucleus of M32 in X-rays,...
Ho, Luis C., Terashima, Yuichi, Okajima, Takashi
The globular cluster M15 has recently been found to host a possible central black hole with a mass of ~2000 solar masses. A deep, high-resolution Chandra image failed to detect the "nucleus" of the...
The stellar content of nuclear star clusters in spiral galaxies (2003)
Böker, Torsten, Van Der Marel, Roeland P., Gerssen, Joris, Walcher, Jakob, Rix, Hans-Walter, Shields, Joseph C., ...
Axisymmetric Dynamical Models Of The Central Regions Of Galaxies (2003)
Karl Gebhardt, Douglas Richstone, Scott Tremaine, Tod R. Lauer, Ralf Bender, Alan Dressler, ...
We present axisymmetric, orbit superposition models for 12 galaxies using data taken with the Hubble Space Telescope (HST) and ground-based observatories. In each galaxy, we detect a central black...
Jason Pinkney, Karl Gebhardt, Ralf Bender, Alan Dressler, S. M. Faber, Alexei V. Filippenko, ...
We present stellar kinematics for a sample of 10 early-type galaxies observed using the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope, and the Modular Spectrograph on...
Ho, Luis C., Filippenko, Alexei V., Sargent, Wallace L. W.
We use the database from Paper III to quantify the global and nuclear properties of emission-line nuclei in the Palomar spectroscopic survey of nearby galaxies. We show that the host galaxies of...
Axisymmetric Dynamical Models of the Central Regions of Galaxies (2002)
Gebhardt, Karl, Richstone, Douglas, Tremaine, Scott, Lauer, Tod R., Bender, Ralf, Bower, Gary, ...
We present axisymmetric, orbit superposition models for 12 galaxies using data taken with the Hubble Space Telescope (HST) and ground-based observatories. In each galaxy, we detect a central black...
A Search for Active Galactic Nuclei in Sc Galaxies with H II Spectra (2002)
Ulvestad, James S., Ho, Luis C.
(Abridged) We have searched for nuclear radio emission from a statistically complete sample of 40 Sc galaxies within 30 Mpc that are optically classified as star-forming objects, in order to...
Ravindranath, Swara, Ho, Luis C.
We present imaging and spectroscopic observations of the gravitationally lensed arcs in the field of RX J1347.5-1145, the most X-ray luminous galaxy cluster known. Based on the detection of the [OII]...
Galaxies with a Central Minimum in Stellar Luminosity Density (2002)
Lauer, Tod R., Gebhardt, Karl, Richstone, Douglas, Tremaine, Scott, Bender, Ralf, Bower, Gary, ...
We used HST WFPC2 images to identify six early-type galaxies with surface- brightness profiles that decrease inward over a limited range of radii near their centers. The implied luminosity density...
The Radio Properties of Composite LINER/HII Galaxies (2002)
Filho, Mercedes E., Barthel, Peter D., Ho, Luis C.
Arcsec-resolution VLA observations -- newly obtained as well as published -- of 40 nearby galaxies are discussed, completing a study of the radio properties of a magnitude-limited sample of nearby...
Detailed Structural Decomposition of Galaxy Images (2002)
Peng, Chien Y., Ho, Luis C., Impey, Chris D., Rix, Hans-Walter
We present a two-dimensional (2-D) fitting algorithm (GALFIT) designed to extract structural components from galaxy images, with emphasis on closely modeling light profiles of spatially...
The slope of the black-hole mass versus velocity dispersion correlation (2002)
Tremaine, Scott, Gebhardt, Karl, Bender, Ralf, Bower, Gary, Dressler, Alan, Faber, S. M., ...
Observations of nearby galaxies reveal a strong correlation between the mass of the central dark object M and the velocity dispersion sigma of the host galaxy, of the form log(M/M_sun) = a +...
Terashima, Yuichi, Iyomoto, Naoko, Ho, Luis C., Ptak, Andrew F.
This paper presents a comprehensive study of the X-ray properties of low-ionization nuclear emission-line regions (LINERs) and low-luminosity Seyfert galaxies based on observations obtained with...
Fe K Emission Lines in Low-luminosity AGNs (2002)
Terashima, Yuichi, Iyomoto, Naoko, Ho, Luis C., Ptak, Andrew F.
We present the results of a systematic analysis of Fe K emission lines in low-luminosity AGNs (LLAGNs) observed with ASCA. We used a sample of LLAGNs with small intrinsic absorption to compare with...
Light-year Scale Radio Cores in Four LINER Galaxies (2002)
Filho, Mercedes E., Barthel, Peter D., Ho, Luis C.
The LINER galaxies NGC 2911, NGC 3079, NGC 3998, and NGC 6500 were observed at 5 GHz with the European VLBI Network at a resolution of 5 milliarcsecond and found to possess flat-spectrum, variable,...
Limits on the Mass of the Central Black Hole in 16 Nearby Bulges (2002)
Sarzi, Marc, Rix, Hans-Walter, Shields, Joseph C., McIntosh, Daniel H., Ho, Luis C., Rudnick, Gregory, ...
Detailed Structural Decomposition of Galaxy Images (2002)
Peng, Chien Y., Ho, Luis C., Impey, Chris D., Rix, Hans-Walter
Ho, Luis C., Sarzi, Marc, Rix, Hans-Walter, Shields, Joseph C., Rudnick, Greg, Filippenko, Alexei V., ...
Tod Lauer National, Tod R. Lauer, Karl Gebhardt, Scott Tremaine, Ralf Bender, Gary Bower, ...
We used Hubble Space Telescope WFPC2 images to identify six early-type galaxies with surface-brightness profiles that decrease inward over a limited range of radii near their centers. The implied...
The Slope of the Black-Hole Mass versus Velocity Dispersion Correlation (2002)
Scott Tremaine, Karl Gebhardt, Ralf Bender, Gary Bower, Alan Dressler, S. M. Faber, ...
Observations of nearby galaxies reveal a strong correlation between the mass of the central dark object M . and the velocity dispersion # of the host galaxy, of the form log(M . /M# ) = # + # log(#/#...
Boeker, Torsten, Laine, Seppo, Van Der Marel, Roeland P., Sarzi, Marc, Rix, Hans-Walter, Ho, Luis C., ...
We present new HST I-band images of a sample of 77 nearby, late-type spiral galaxies with low inclination. The main purpose of this catalog is to study the frequency and properties of nuclear star...
Ho, Luis C., Sarzi, Marc, Rix, Hans-Walter, Shields, Joseph C., Rudnick, Greg, Filippenko, Alexei V., ...
Gas-dynamical studies using the Hubble Space Telescope are an integral component for future progress in the search for massive black holes in galactic nuclei. Here we present an extensive set of gas...
Measuring Black Hole Masses Using Ionized Gas Kinematics (2001)
Barth, Aaron J., Sarzi, Marc, Ho, Luis C., Rix, Hans-Walter, Shields, Joseph C., Filippenko, Alexei V., ...
We describe techniques for measuring the central masses of galaxies using emission-line kinematics observed with the Hubble Space Telescope. For accurate results, it is necessary to model various...
Limits on the Mass of the Central Black Hole in 16 Nearby Bulges (2001)
Sarzi, Marc, Rix, Hans-Walter, Shields, Joseph C., McIntosh, Daniel H., Ho, Luis C., Rudnick, Greg, ...
We report upper limits on the masses of black holes that can be present in the centers of 16 nearby galaxy bulges. These limits for our statistically complete sample were derived from the modeling of...
Ulvestad, James S., Ho, Luis C.
The low-luminosity active galactic nuclei in NGC 3147, NGC 4203, and NGC 4579 have been imaged at four frequencies with the Very Long Baseline Array. The galaxies are unresolved at all frequencies,...
The Population of AGNs in Nearby Galaxies (2001)
This contribution reviews the properties of nuclear activity in nearby galaxies, with emphasis on results obtained from current optical surveys and multiwavelength follow-up observations thereof.
Nonstandard Central Engines in Nearby Galaxies (2001)
We argue that nearby galaxy nuclei contain massive black holes that are fueled by low radiative efficiency accretion flows.
On the Relationship Between Radio Emission and Black Hole Mass in Galactic Nuclei (2001)
We use a comprehensive database of black hole masses and nuclear luminosities to investigate the relationship between radio emission and black hole mass. Our sample covers a wide range of nuclear...
Nuclear Cusps and Cores in Early-type Galaxies As Relics of Binary Black Hole Mergers (2001)
Ravindranath, Swara, Ho, Luis C., Filippenko, Alexei V.
We present an analysis of the central cusp slopes and core parameters of early-type galaxies using a large database of surface brightness profiles obtained from Hubble Space Telescope observations....
Maoz, Dan, Ho, Luis C., Sternberg, Amiel
We present 3000--10000 Ang HST/STIS long-slit spectroscopy of the bright super star cluster A (SSC-A) in the dwarf starburst galaxy NGC 1569. The 0.05" HST angular resolution allows, for the first...
Central Structural Parameters of Early-Type Galaxies as Viewed with HST/NICMOS (2001)
Ravindranath, Swara, Ho, Luis C., Peng, Chien Y., Filippenko, Alexei V., Sargent, Wallace L. W.
We present surface photometry for the central regions of a sample of 33 early-type (E, S0, and S0/a) galaxies observed at 1.6 microns (H band) using the Hubble Space Telescope (HST). We employ a new...
Statistical Properties of Radio Emission from the Palomar Seyfert Galaxies (2001)
Ulvestad, James S., Ho, Luis C.
We have carried out an analysis of the radio and optical properties of a statistical sample of 45 Seyfert galaxies from the Palomar spectroscopic survey of nearby galaxies. We find that the space...
Halderson, Eve L., Moran, Edward C., Filippenko, Alexei V., Ho, Luis C.
We have examined ROSAT soft X-ray observations of a complete, distance-limited sample of Seyfert and LINER galaxies. X-ray data are available for 46 out of 60 such objects which lie within a...
Maoz, Dan, Barth, Aaron J., Ho, Luis C., Sternberg, Amiel, Filippenko, Alexei V.
We present broad-band (U, V, I,and H) and narrow-band(H-alpha+[N II] and Paschen-alpha) images of the circumnuclear starburst rings in two nearby spiral galaxies, NGC 1512 and NGC 5248, obtained with...
Nuclear Luminosities and Radio Loudness of Seyfert Nuclei (2001)
Historically, Seyfert nuclei have been considered to be radio-quiet active galactic nuclei (AGNs). We question this widely held assumption by showing that the distribution of the radio-to-optical...
Detection of Nuclear X-ray Sources in Nearby Galaxies with Chandra (2001)
Ho, Luis C., Feigelson, Eric D., Townsley, Leisa K., Sambruna, Rita M., Garmire, Gordon P., Brandt, W. N., ...
We report preliminary results from an arcsecond-resolution X-ray survey of nearby galaxies using ACIS on board Chandra. The total sample consists of 41 low-luminosity AGNs, including Seyferts,...
Ravindranath, Swara, Ho, Luis C., Peng, Chien Y., Filippenko, Alexei V., Sargent, Wallace L. W.
We present preliminary results from surface photometry of a sample of early-type galaxies observed with NICMOS on board HST in the F160W (H-band) filter. Dust is found to occur mostly in galaxies...
Radio Continuum Survey of an Optically-Selected Sample of Nearby Seyfert Galaxies (2001)
Ho, Luis C., Ulvestad, James S.
We have used the Very Large Array (VLA) to conduct a survey for radio continuum emission in the sample of 52 Seyfert nuclei selected from the optical spectroscopic galaxy catalog of Ho, Filippenko,...
Chien Y. Peng, Luis C. Ho, Chris D. Impey, Hans-walter Rix
We present a two-dimensional fitting algorithm (GALFIT) designed to extract structural components from galaxy images, with emphasis on closely modeling light profiles of spatially well-resolved,...
Supermassive Black Holes from the SUNNS survey (2000)
Sarzi, Marc, Rix, Hans-Walter, Shields, Joseph C., Rudnick, Greg, Ho, Luis C., McIntosh, Daniel H., ...
We report three new accurate mass measurements for the supermassive black holes hosted by the early-type disk galaxies NGC2787, NGC4459 and NGC4596. The targets were selected from a larger set of...
SuperMassive Black Holes in Bulges (2000)
Sarzi, Marc, Rix, Hans-Walter, Shields, Joseph C., Rudnick, Greg, Ho, Luis C., McIntosh, Daniel H., ...
We present spatially extended gas kinematics at parsec-scale resolution for the nuclear regions of four nearby disk galaxies, and model them as rotation of a gas disk in the joint potential of the...
Hard X-ray Emission and the Ionizing Source in LINERs (2000)
Terashima, Yuichi, Ho, Luis C., Ptak, Andrew F.
We report X-ray fluxes in the 2--10 keV band from LINERs (low-ionization nuclear emission-line regions) and low-luminosity Seyfert galaxies obtained with the ASCA satellite. Observed X-ray...
A Relationship Between Nuclear Black Hole Mass and Galaxy Velocity Dispersion (2000)
Gebhardt, Karl, Bender, Ralf, Bower, Gary, Dressler, Alan, Faber, S. M., Filippenko, Alexei V., ...
We describe a correlation between the mass M_BH of a galaxy's central black hole and the luminosity-weighted line-of-sight velocity dispersion sigma_e within the half-light radius. The result is...
Detailed Analysis of Early to Late-Time Spectra of Supernova 1993J (2000)
Matheson, Thomas, Filippenko, Alexei V., Ho, Luis C., Barth, Aaron J., Leonard, Douglas C.
We present a detailed study of line structure in early to late-time spectra of Supernova (SN) 1993J. Spectra during the nebular phase, but within the first two years after explosion, exhibit...
Nagar, Neil M., Falcke, Heino, Wilson, Andrew S., Ho, Luis C.
We report a 0.2" resolution, 15 GHz survey of a sample of 48 low-luminosity active galactic nuclei with the Very Large Array. Compact radio emission has been detected in 57% (17 of 30) of LINERs and...
Double-Peaked Broad Emission Lines in NGC 4450 and Other LINERs (2000)
Ho, Luis C., Rudnick, Greg, Rix, Hans-Walter, Shields, Joseph C., McIntosh, Daniel H., Filippenko, Alexei V., ...
Spectra taken with HST reveal that NGC 4450 emits Balmer emission lines with displaced double peaks and extremely high-velocity wings. This characteristic line profile, previously seen in a few...
Evidence for a Black Hole and Accretion Disk in the LINER NGC 4203 (2000)
Shields, Joseph C., Rix, Hans-Walter, McIntosh, Daniel H., Ho, Luis C., Rudnick, Greg, Filippenko, Alexei V., ...
We present spectroscopic observations from the Hubble Space Telescope that reveal for the first time the presence of a broad pedestal of Balmer-line emission in the LINER galaxy NGC 4203. The...
Supermassive Black Holes in Active Galactic Nuclei (2000)
This article gives a brief overview of the direct and indirect evidence in support of the standard paradigm that active galactic nuclei are powered by supermassive black holes.
Supermassive Black Holes in Inactive Galaxies (2000)
This article discusses stellar dynamical evidence for supermassive black holes in inactive and weakly active galaxies.
The Nature of Composite LINER/HII Galaxies, As Revealed from High-Resolution VLA Observations (2000)
Filho, Mercedes E., Barthel, Peter D., Ho, Luis C.
A sample of 37 nearby galaxies displaying composite LINER/HII and pure HII spectra was observed with the VLA in an investigation of the nature of their weak radio emission. The resulting radio...
Black Hole Mass Estimates from Reverberation Mapping and from Spatially Resolved Kinematics (2000)
Karl Gebhardt, John Kormendy, Luis C. Ho, Ralf Bender, Gary Bower, Alan Dressler, ...
Black hole (BH) masses that have been measured by reverberation mapping in active galaxies fall significantly below the correlation between bulge luminosity and BH mass determined from spatially...
A Relationship Between Nuclear Black Hole Mass And Galaxy Velocity Dispersion (2000)
Karl Gebhardt, Ralf Bender, Alan Dressler, S. M. Faber, Alexei V, Richard Green, ...
We describe a correlation between the mass M of a galaxy's central black hole and the luminosity-weighted line-of-sight velocity dispersion e within the half-light radius. The result is based on...
Quataert, Eliot, Di Matteo, Tiziana, Narayan, Ramesh, Ho, Luis C.
M81 and NGC 4579 are two of the few low-luminosity active galactic nuclei which have an estimated mass for the central black hole, detected hard X-ray emission, and detected optical/UV emission. In...
Discovery of Radio Outbursts in the Active Nucleus of M81 (1999)
Ho, Luis C., Van Dyk, Schuyler D., Pooley, Guy G., Sramek, Richard A., Weiler, Kurt W.
The low-luminosity active galactic nucleus of M81 has been monitored at centimeter wavelengths since early 1993 as a by-product of radio programs to study the radio emission from Supernova 1993J. The...
The Spectral Energy Distributions of Low-Luminosity Active Galactic Nuclei (1999)
As a step toward elucidating the physical conditions in nearby active galaxies, this paper presents spectral energy distributions (SEDs) of a sample of seven low-luminosity active galactic nuclei...
X-ray Properties of the Weak Seyfert 1 Nucleus in NGC 4639 (1999)
Ho, Luis C., Ptak, Andrew, Terashima, Yuichi, Kunieda, Hideyo, Serlemitsos, Peter J., Yaqoob, Tahir, ...
We obtained observations of NGC 4639 with ASCA in order to investigate its mildly active Seyfert 1 nucleus at hard X-ray energies. Koratkar et al. (1995) have previously shown that the nucleus is a...
Kraemer, Steven B., Ho, Luis C., Crenshaw, D. Michael, Shields, Joseph C., Filippenko, Alexei V.
We have combined Hubble Space Telescope/Faint Object Spectrograph, ground-based, and Infrared Space Observatory spectra of the nucleus of NGC 4395, the least luminous and nearest known type 1 Seyfert...
VLA and VLBA observations of compact radio cores in LINER galaxies (1998)
Falcke, Heino, Ho, Luis C., Ulvestad, James S., Wilson, Andrew S., Nagar, Neil M.
A VLA survey of nearby LINER galaxies at 15 GHz has revealed the presence of a compact radio core in many sources. The cores seem to be correlated with the optical activity. Follow-up VLBA...
What Powers the Compact Radio Emission in Nearby Elliptical and S0 Galaxies? (1998)
Many nearby early-type (elliptical and S0) galaxies contain weak (milli-Jansky level) nuclear radio sources on scales a few hundred parsecs or less. The origin of the radio emission, however, has...
LINERs as Low-Luminosity Active Galactic Nuclei (1998)
Many nearby galaxies contain optical signatures of nuclear activity in the form of LINER nuclei. LINERs may be the weakest and most common manifestation of the quasar phenomenon. The physical origin...
Supermassive Black Holes in Galactic Nuclei (1998)
I review the status of observational determinations of central masses in nearby galactic nuclei. Results from a variety of techniques are summarized, including ground-based and space-based optical...
The Ultraviolet Spectra of LINERs: A Comparative Study (1997)
Maoz, Dan, Koratkar, Anuradha, Shields, Joseph C., Ho, Luis C., Filippenko, Alexei V., Sternberg, Amiel
Imaging studies have shown that about 25% of LINER galaxies display a compact nuclear UV source. As part of a program to study the nature of LINERs and their connection to the active galaxy...
A Search for "Dwarf" Seyfert Nuclei. IV. Nuclei with Broad H-alpha Emission (1997)
Ho, Luis C., Filippenko, Alexei V., Sargent, Wallace L. W., Peng, Chien Y.
We present the results of an optical spectroscopic survey designed to search for low-luminosity, "dwarf" Seyfert nuclei in a magnitude-limited sample of 486 bright, northern galaxies....
The Influence of Bars on Nuclear Activity (1997)
Ho, Luis C., Filippenko, Alexei V., Sargent, Wallace L. W.
We test ideas on fueling of galactic nuclei by bar-driven inflow by comparing the detection rate and intensity of nuclear H II regions and AGNs among barred and unbarred galaxies in a sample of over...
Properties of H II Regions in the Centers of Nearby Galaxies (1997)
Ho, Luis C., Filippenko, Alexei V., Sargent, Wallace L. W.
As part of an optical spectroscopic survey of nearby, bright galaxies, we have identified a sample of over 200 emission-line nuclei having optical spectra resembling those of giant extragalactic H II...
Ho, Luis C., Filippenko, Alexei V., Sargent, Wallace L. W.
We have completed an optical spectroscopic survey of the nuclear regions (r < 200 pc) of a large sample of nearby galaxies. Although the main objectives of the survey are to search for low-luminosity...
A Search for "Dwarf" Seyfert Nuclei. V. Demographics of Nuclear Activity in Nearby Galaxies (1997)
Ho, Luis C., Filippenko, Alexei V., Sargent, Wallace L. W.
We use the sample of emission-line nuclei derived from a recently completed optical spectroscopic survey of nearby galaxies to quantify the incidence of local (z = 0) nuclear activity. Consistent...
Relativistic Jets in Radio-Weak Quasars and LINER Galaxies (1997)
Heino Falcke, Andrew S. Wilson, Luis C. Ho
: We discuss radio observations of a sample of radio-weak and radio-intermediate quasars which demonstrate that -- just like their radio-loud counterparts -- radioweak quasars too have relativistic...
Low-Luminosity Seyfert Nuclei (1996)
Ho, Luis C., Filippenko, Alexei V., Sargent, Wallace L. W.
We describe a new sample of Seyfert nuclei discovered during the course of an optical spectroscopic survey of nearby galaxies. The majority of the objects, many recognized for the first time, have...
Ho, Luis C., Filippenko, Alexei V.
We present evidence that some of the compact, luminous, young star clusters recently discovered through images taken with the Hubble Space Telescope (HST) have masses comparable to those of old...
Young Star Clusters in Starburst Environments (1996)
Recent high-resolution observations with the Hubble Space Telescope (HST) reveal that young star clusters of extraordinary luminosity and compactness ("super star clusters") are commonly found in...
Dynamical Evidence for a Luminous, Young Globular Cluster in NGC 1569 (1996)
Ho, Luis C., Filippenko, Alexei V.
Recent high-resolution observations with the Hubble Space Telescope (HST) reveal that star clusters of extraordinary luminosity and compactness are commonly found in a variety of starburst systems....
Optical Spectroscopy of LINERs and Low-Luminosity Seyfert Nuclei (1996)
An unprecedentedly large number of LINERs has been discovered in a recently completed optical spectroscopic survey of nearby galaxies, allowing several statistical properties of the host galaxies and...
An Atlas of Hubble Space Telescope Ultraviolet Images of Nearby Galaxies (1996)
Maoz, Dan, Filippenko, Alexei V., Ho, Luis C., Macchetto, F. Duccio, Rix, Hans-Walter, Schneider, Donald P.
We present an atlas of UV ($\sim 2300$ \AA) images, obtained with the Hubble Space Telescope (HST) Faint Object Camera, of the central $22''\times 22''$ of 110 galaxies. The observed galaxies are an...
Hubble Space Telescope Ultraviolet Images of Five Circumnuclear Star-Forming Rings (1996)
Maoz, Dan, Barth, Aaron J., Sternberg, Amiel, Filippenko, Alexei V., Ho, Luis C., Macchetto, F. Duccio, ...
We present UV (2300 Ang) images, obtained with the HST Faint Object Camera, of the central 20'' of five galaxies containing circumnuclear star-forming rings. The five galaxies are from a well-defined...
Detection of Compact Ultraviolet Nuclear Emission in LINER Galaxies (1994)
Maoz, Dan, Filippenko, Alexei V., Ho, Luis C., Rix, Hans-Walter, Bahcall, John N., Schneider, Donald P., ...
Low-ionization nuclear emission-line regions (LINERs), which exist in a large fraction of galaxies, may be the least luminous manifestation of quasar activity. The nature of LINERs has, however,...