Search Publications
HST STIS Spectroscopy of the Triple Nucleus of M31: Two Nested Disks in Keplerian Rotation around a Supermassive Black Hole
Richstone, Douglas; Kormendy, John; Lauer, Tod R. +12 more
We present Hubble Space Telescope (HST) spectroscopy of the nucleus of M31 obtained with the Space Telescope Imaging Spectrograph (STIS). Spectra that include the Ca II infrared triplet (λ~=8500 Å) see only the red giant stars in the double brightness peaks P1 and P2. In contrast, spectra taken at λ~=3600-5100 Å are sensitive to the tiny blue nucl…
Stellar Populations in 10 Clump-Cluster Galaxies of the Hubble Ultra Deep Field
Elmegreen, Bruce G.; Elmegreen, Debra Meloy
Color-color diagrams for the clump and interclump emission in 10 clump-cluster galaxies of the Hubble Ultra Deep Field (UDF) are made from B,V, i, and z images and compared with models to determine redshifts, star formation histories, and galaxy masses. These galaxies are members of a class dominated by 5-10 giant clumps, with no exponential disk …
The Age Distribution of Massive Star Clusters in the Antennae Galaxies
Whitmore, Bradley C.; Fall, S. Michael; Chandar, Rupali
We determine the age distribution of star clusters in the Antennae galaxies (NGC 4038/9) for two mass-limited samples (M>3×104 Msolar and M>2×105 Msolar). This is based on integrated broadband UBVI and narrowband Hα photometry from deep images taken with the Hubble Space Telescope. We find that the…
Masses of Star Clusters in the Nuclei of Bulgeless Spiral Galaxies
Ho, L. C.; Rix, H. -W.; Shields, J. C. +6 more
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 (106-108 Lsolar) but compact (re~5 pc) nuclear star clusters in very late type spirals with the Ultraviolet and Visual Echelle Spec…
GEMS: The Surface Brightness and Surface Mass Density Evolution of Disk Galaxies
Bell, Eric F.; Somerville, Rachel S.; Wisotzki, Lutz +14 more
We combine HST imaging from the GEMS (Galaxy Evolution from Morphologies and SEDs) survey with photometric redshifts from COMBO-17 to explore the evolution of disk-dominated galaxies since z<~1.1. The sample is composed of all GEMS galaxies with Sérsic indices n<2.5, derived from fits to the galaxy images. We account fully for selection effe…
The Surprisingly Steep Mass Profile of A1689, from a Lensing Analysis of Subaru Images
Kong, X.; Broadhurst, T.; Umetsu, K. +4 more
Subaru observations of A1689 (z=0.183) are used to derive an accurate, model-independent mass profile for the entire cluster, r<~2 Mpc h-1, by combining magnification bias and distortion measurements. The projected mass profile steepens quickly with increasing radius, falling away to zero at r~1.0 Mpc h-1, well short of th…
The Central Region of Barred Galaxies: Molecular Environment, Starbursts, and Secular Evolution
Scoville, Nick; Jogee, Shardha; Kenney, Jeffrey D. P.
Stellar bars drive gas into the circumnuclear (CN) region of galaxies. To investigate the fate of the CN gas and star formation (SF), we study a sample of barred nonstarbursts and starbursts with high-resolution CO, optical, Hα, radio continuum, Brγ, and HST data, and find the following. (1) The inner kiloparsec of bars differs markedly from the o…
A Jovian-Mass Planet in Microlensing Event OGLE-2005-BLG-071
Bennett, D. P.; Gal-Yam, A.; Soszyński, I. +34 more
We report the discovery of a several-Jupiter-mass planetary companion to the primary lens star in microlensing event OGLE-2005-BLG-071. Precise (<~1%) photometry at the peak of the event yields an extremely high signal-to-noise ratio detection of a deviation from the light curve expected from an isolated lens. The planetary character of this de…
Solar-like Oscillations in α Centauri B
Butler, R. Paul; Bedding, Timothy R.; Marcy, Geoffrey W. +6 more
We have made velocity observations of the star α Centauri B from two sites, allowing us to identify 37 oscillation modes with l=0-3. Fitting to these modes gives the large and small frequency separations as a function of frequency. The mode lifetime, as measured from the scatter of the oscillation frequencies about a smooth trend, is similar to th…
The Luminosity, Stellar Mass, and Number Density Evolution of Field Galaxies of Known Morphology from z = 0.5 to 3
Papovich, Casey; Conselice, Christopher J.; Blackburne, Jeffrey A.
The evolution of rest-frame B-band luminosities, stellar masses, and number densities of field galaxies in the Hubble Deep Fields North and South are studied as a function of rest-frame B-band morphological type out to redshift z~3 using a sample of 1231 I<27 galaxies with spectroscopic and photometric redshifts. We find that the comoving and r…