590 citations · 8.8k across the 153 of their papers we have counts for
94 papers · 1 filter
Old-Population Hypervelocity Stars from the Galactic Center: Limits from the SDSS
Juna A. Kollmeier, Andrew Gould, Gillian Knapp +1
We present limits on the ejection of old-population HVS from a sample of over 290,000 stars selected from the SDSS. We derive the speed at the solar circle from the measured positi…
Where are the Old-Population High Velocity Stars?
Juna A. Kollmeier, Andrew Gould
To date, all of the reported high velocity stars (HVSs), which are believed to be ejected from the Galactic center, are blue and therefore almost certainly young. Old-population HV…
Photometric Selection of QSO Candidates From GALEX Sources
David W. Atlee, Andrew Gould
We present a catalog of 36,120 QSO candidates from the Galaxy Evolution Explorer (GALEX) Release Two (GR2) UV catalog and the USNO-A2.0 optical catalog. The selection criteria are…
Black Hole Masses and Eddington Ratios at 0.3<z<4
Juna A. Kollmeier, Christopher A. Onken, Christopher S. Kochanek +9
We study the distribution of Eddington luminosity ratios, L_bol/L_edd, of active galactic nuclei (AGNs) discovered in the AGN and Galaxy Evolution Survey (AGES). We combine H-beta,…
Proper Motion Catalog From SDSS \intersect USNO-B
Andrew Gould, Juna A. Kollmeier
We present a catalog of 345,000 stars with proper motions μ> 20 mas/yr and magnitudes r' <20, drawn from the intersection of the SDSS Data Release One and USNO-B. We first use SDSS…
M Dwarfs from Hubble Space Telescope Star Counts. V. The I-band Luminosity Function
Zheng Zheng, Chris Flynn, Andrew Gould +2
We derive the disk I-band luminosity function from the Zheng et al. sample of \~1400 disk M dwarfs observed with the Hubble Space Telescope. We adopt a Galactic-height-dependent co…
Early-type Stars: Most Favorable Targets for Astrometrically Detectable Planets in the Habitable Zone
Andrew Gould, Debra A. Fischer
Early-type stars appear to be a difficult place to look for planets astrometrically. First, they are relatively heavy, and for fixed planetary mass the astrometric signal falls inv…
Transit Target Selection Using Reduced Proper Motions
Andrew Gould, Christopher W. Morgan
In searches for planetary transits in the field, well over half of the survey stars are typically giants or other stars that are too large to permit straightforward detection of pl…
Stellar Halo Parameters from 4588 Subdwarfs
Andrew Gould
Using a reduced proper motion discriminator, I obtain a sample of 4588 subdwarfs from the Revised NLTT Catalog of Salim & Gould. The ample statistics and low contamination permit m…
Improved Astrometry and Photometry for the Luyten Catalog. II. Faint Stars and the Revised Catalog
Samir Salim, Andrew Gould
We complete construction of a catalog containing improved astrometry and new optical/infrared photometry for the vast majority of NLTT stars lying in the overlap of regions covered…
Classifying Luyten Stars Using An Optical-Infrared Reduced Proper Motion Diagram
Samir Salim, Andrew Gould
We present a V-J reduced proper motion (RPM) diagram for stars in the New Luyten Two-Tenths (NLTT) catalog. In sharp contrast to the RPM diagram based on the original NLTT data, th…
Observation of periodic variable stars towards the galactic spiral arms by EROS II
F. Derue, J. B. Marquette, S. Lupone +11
We present the results of a massive variability search based on a photometric survey of a six square degree region along the Galactic plane at (, ) a…
Improved Astrometry and Photometry for the Luyten Catalog. I. Bright Stars
Andrew Gould, Samir Salim
We outline the construction of an updated version of the New Luyten Two-Tenths (NLTT) catalog of high proper motion stars, which will contain improved astrometry and photometry for…
Microlens Parallaxes of Binary Lenses Measured from a Satellite
David S. Graff, Andrew Gould
Caustic-crossing binary lenses make up about 5% of all detected microlenses. The relative proper motion of a caustic-crossing binary lens can be measured with observations from a s…
Millisecond Pulsars as Probes of Mass Segregation in the Galactic Center
Julio Chaname, Andrew Gould
We propose a simple test for the existence of a cluster of black hole remnants around Sgr A* that is based on a small sample of any type of Galactic Center objects, provided they a…
Searching for Failed Supernovae With Astrometric Binaries
Andrew Gould, Samir Salim
Stars in the mass range 8 Msun<M<30 Msun are thought to end their lives as luminous supernovae that leave behind a neutron star. However, if a substantial fraction of these stars i…
Astrometry Survey Missions Beyond the Magnitude Limit
Samir Salim, Andrew Gould, Rob Olling
Three planned astrometry survey satellites, FAME, DIVA, and GAIA, all aim at observing magnitude-limited samples. We argue that substantial additional scientific opportunities are…
Applications of Microlensing to Stellar Astrophysics
Andrew Gould
Over the past decade, microlensing has developed into a powerful tool to study stellar astrophysics, especially stellar atmospheres, stellar masses, and binarity. I review this pro…
M Dwarfs from Hubble Space Telescope Star Counts. IV
Zheng Zheng, Chris Flynn, Andrew Gould +2
We study a sample of about 1400 disk M dwarfs that are found in 148 fields observed with the Wide Field Camera 2 (WFC2) on the Hubble Space Telescope and 162 fields observed with p…
Microlensing by Stellar Black Holes Around Sgr A*
Julio Chaname, Andrew Gould, Jordi Miralda-Escude
We show that at any given time, the Galactocentric black hole Sgr A* is expected to be microlensing N(lens)=1.7 bulge stars if the threshold of detectability of the fainter image i…
Analytic Study of Grid Star and Reference Star Selection for the Space Interferometry Mission
Andrew Gould
Grid stars and reference stars provide the fundamental global and local astrometric reference frames for observations by the Space Interferometry Mission. They must therefore be as…
The Ratio of Total to Selective Extinction Toward Baade's Window
Andrew Gould, Amelia Stutz, Jay A. Frogel
We measure the ratio of total to selective extinction, R_{VI}=A_V/E(V-I), toward Baade's Window by comparing the VIK colors of 132 Baade's Window G and K giants from Tiede, Frogel,…
A Cluster of Black Holes at the Galactic Center
Jordi Miralda-Escude, Andrew Gould
If the stellar population of the bulge contains black holes formed in the final core collapse of ordinary stars with M \ga 30 M_{\odot}, then about 25,000 stellar mass black holes…
A Natural Formalism for Microlensing
Andrew Gould
If the standard microlensing geometry is inverted so that the Einstein ring is projected onto the observer plane rather than the source plane, then the relations between the observ…