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Kinematical Structure of the Magellanic System
Roeland P. van der Marel, Nitya Kallivayalil, Gurtina Besla
We review our understanding of the kinematics of the LMC and the SMC, and their orbit around the Milky Way. The line-of-sight velocity fields of both the LMC and SMC have been mapp…
The Binarity of the Magellanic Clouds and the Formation of the Magellanic Stream
Gurtina Besla, Nitya Kallivayalil, Lars Hernquist +4
The HST proper motion (PM) measurements of the Clouds have severe implications for their interaction history with the Milky Way (MW) and with each other. The Clouds are likely on t…
New Analysis of the Proper Motions of the Magellanic Clouds using HST/WFPC2
Nitya Kallivayalil, Roeland P. van der Marel, Jay Anderson +2
In HST Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields in the Magellanic Clouds centered on background quasars. We used these data to determine the proper motion…
Intermediate Mass Black Hole Induced Quenching of Mass Segregation in Star Clusters
Michael Gill, Michele Trenti, M. Coleman Miller +3
In many theoretical scenarios it is expected that intermediate-mass black holes (IMBHs, with masses M ~ 100-10000 solar masses) reside at the centers of some globular clusters. How…
HST/ACS Observations of Star Formation Driven Outflows in Nearby Edge-on Spiral Galaxies: Dependence of Halo Morphology on Star Formation Activity
Joern Rossa, Michael Dahlem, Ralf-Juergen Dettmar +1
(Abridged). We present new high spatial resolution narrowband imaging observations of extraplanar diffuse ionized gas (eDIG) in four late-type, actively star forming edge-on spiral…
I Zw 18 revisited with HST/ACS and Cepheids: New Distance and Age
A. Aloisi, G. Clementini, M. Tosi +9
We present new V and I-band HST/ACS photometry of I Zw 18, the most metal-poor blue compact dwarf (BCD) galaxy in the nearby universe. It has been argued in the past that I Zw 18 i…
Are the Magellanic Clouds on their First Passage about the Milky Way?
Gurtina Besla, Nitya Kallivayalil, Lars Hernquist +4
Recent proper motion measurements of the Large and Small Magellanic Clouds (LMC and SMC, respectively) by Kallivayalil et al (2006a,b) suggest that the 3D velocities of the Clouds…
Supermassive black holes in the Sbc spiral galaxies NGC 3310, NGC 4303 and NGC 4258
Guia Pastorini, Alessandro Marconi, Alessandro Capetti +12
We present new Space Telescope Imaging Spectrograph (STIS) observations of three spiral galaxies, NGC 4303, NGC 3310 and NGC 4258. The bright optical emission lines H $6564…
Nuclear Star Clusters (Nuclei) in Spiral Galaxies and Connection to Supermassive Black Holes
Roeland P. van der Marel, Joern Rossa, Carl Jakob Walcher +4
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 "n…
A New Deep HST/ACS CMD of I Zw 18: Evidence for Red Giant Branch Stars
A. Aloisi, F. Annibali, J. Mack +8
We present results from new deep HST/ACS photometry of I Zw 18, the most metal-poor blue compact dwarf galaxy in the nearby universe. It has been previously argued that this is a v…
The morphology of minor axis gaseous outflows in edge-on Seyfert galaxies
T. P. Robitaille, J. Rossa, D. J. Bomans +1
(Abridged) Spiral galaxies often have extended outflows that permeate beyond the region of the disk. Such outflows have been seen both in starburst galaxies, actively star forming…
Gravity's Relentless Pull: An interactive, multimedia website about black holes for Education and Public Outreach
Roeland P. van der Marel, David Schaller, Gijs Verdoes Kleijn
We have created a website, called "Black Holes: Gravity's Relentless Pull", which explains the physics and astronomy of black holes for a general audience. The site emphasizes user…
The Proper Motion of the Large Magellanic Cloud using HST
Nitya Kallivayalil, Roeland P. van der Marel, Charles Alcock +4
We present a measurement of the systemic proper motion of the Large Magellanic Cloud (LMC) from astrometry with the High Resolution Camera (HRC) of the Advanced Camera for Surveys…
Black Hole Masses and Host Galaxy Evolution of Radio-loud Active Galactic Nuclei
J. -H. Woo, C. M. Urry, R. P. van der Marel +2
We report stellar velocity dispersion measurements for a sample of 28 AGN host galaxies including our previous work. Using the mass-dispersion () and the fundamental…
Supermassive black hole mass measurements for NGC 1300 and NGC 2748 based on HST emission-line gas kinematics
J. W. Atkinson, J. L. Collett, A. Marconi +18
We present Space Telescope Imaging Spectrograph emission-line spectra of the central regions of the spiral galaxies NGC 1300 and NGC 2748. From the derived kinematics of the nuclea…
Masses of star clusters in the nuclei of bulge-less spiral galaxies
C. J. Walcher, R. P. van der Marel, D. McLaughlin +6
In the last decade star clusters have been found in the centers of spiral galaxies across all Hubble types. We here present a spectroscopic study of the exceptionally bright (10^6…
The Fundamental Plane Evolution of Active Galactic Nucleus Host Galaxies
Jong-Hak Woo, Meg Urry, Paulina Lira +2
We measured the stellar velocity dispersions of 15 active galactic nucleus (AGN) host galaxies at redshifts as high as . Combining these with published velocity dispersi…
The Large Magellanic Cloud: Structure and Kinematics
Roeland P. van der Marel
I review our understanding of the structure and kinematics of the Large Magellanic Cloud (LMC), with a particular focus on recent results. This is an important topic, given the sta…
The Nuclei of Late-type Spiral Galaxies
T. Boeker, C. -J. Walcher, H. -W. Rix +8
We summarize some recent results from our observational campaign to study the central regions of spiral galaxies of late Hubble type (Scd - Sm). These disk-dominated, bulgeless gal…
Hubble Space Telescope/WFPC2 Investigation of the Nuclear Morphology in the Toomre Sequence of Merging Galaxies
Seppo Laine, Roeland P. van der Marel, Joern Rossa +4
We report on the properties of nuclear regions in the Toomre Sequence of merging galaxies, based on imaging data gathered with the Hubble Space Telescope WFPC2 camera. We have imag…
What Drives the Central Velocity Dispersion in Nearby Early-Type Galaxies?
G. Verdoes Kleijn, R. van der Marel, J. Noel-Storr
The majority of nearby early-type galaxies contains detectable amounts of emission-line gas at their centers. The emission-line ratios and gas kinematics potentially form a valuabl…
Internal Dynamics, Structure and Formation of Dwarf Elliptical Galaxies: II. Rotating Versus Non-Rotating Dwarfs
M. Geha, P. Guhathakurta, R. van der Marel
We present spatially-resolved internal kinematics and stellar chemical abundances for a sample of dwarf elliptical (dE) galaxies in the Virgo Cluster observed with Keck/ESI. We fin…
Intermediate-Mass Black Holes in the Universe: A Review of Formation Theories and Observational Constraints
Roeland P. van der Marel
This paper reviews the subject of intermediate-mass black holes (IMBHs) with masses between those of "stellar-mass" and "super-massive" black holes. The existence of IMBHs is a rea…
Is there really a Black Hole at the center of NGC 4041? - Constraints from gas kinematics
A. Marconi, D. J. Axon, A. Capetti +16
We present HST/STIS spectra of the Sbc spiral galaxy NGC 4041 which were used to map the velocity field of the gas in its nuclear region. We detect the presence of a compact (r~0.4…