Search Publications
Photolytically Generated Aerosols in the Mesosphere and Thermosphere of Titan
Shemansky, Donald E.; Liang, Mao-Chang; Yung, Yuk L.
Analysis of the Cassini Ultraviolet Imaging Spectrograph (UVIS) stellar and solar occultations at Titan to date include 12 species: N2 (nitrogen), CH4 (methane), C2H2 (acetylene), C2H4 (ethylene), C2H6 (ethane), C4H2 (diacetylene), C6…
The Metallicity Distribution of Intracluster Stars in Virgo
Ferguson, Henry C.; Williams, Benjamin F.; Gerhard, Ortwin +11 more
We have used the Hubble Space Telescope's Advanced Camera for Surveys (ACS) to detect and measure ~5300 stars in a single intracluster field in the Virgo Cluster. By performing F606W and F814W photometry on these stars, we have determined their metallicity distribution function and constrained the types of stars present in this portion of Virgo's …
The UDF05 Follow-up of the Hubble Ultra Deep Field. I. The Faint-End Slope of the Lyman Break Galaxy Population at z ~ 5
Panagia, N.; Gardner, Jonathan P.; Ferguson, H. C. +14 more
We present the UDF05 HST program, which consists of three disjoint fields-NICP12, NICP34, plus the HUDF-with deep ACS (F606W, F775W, and F850LP) and NICMOS (F110W and F160W) imaging. Here we use the ACS data for the NICP12 and HUDF fields to implement a (V-i)-(i-z) selection criterion that allows us to identify a sample of 101 (133) z~5 Lyman brea…
Multispacecraft Measurement of Anisotropic Correlation Functions in Solar Wind Turbulence
Horbury, T. S.; Osman, K. T.
Multispacecraft measurements in the solar wind are used to determine the field-aligned anisotropy of magnetohydrodynamic inertial range turbulence. The ratio of the parallel to perpendicular correlation lengths is measured by using time-lagged two-point correlations to construct a spatial autocorrelation function. The mean ratio obtained, 1.79+/-0…
The Globular Cluster Luminosity Function and Specific Frequency in Dwarf Elliptical Galaxies
Miller, Bryan W.; Lotz, Jennifer M.
The globular cluster luminosity function, specific globular cluster frequency, SN, specific globular cluster mass, TMP, and globular cluster mass fraction in dwarf elliptical galaxies are explored using the full 69 galaxy sample of the HST WFPC2 Dwarf Elliptical Galaxy Snapshot Survey. The GCLFs of the dEs are well represente…
Star Formation via the Little Guy: A Bayesian Study of Ultracool Dwarf Imaging Surveys for Companions
Allen, Peter R.
I have undertaken a comprehensive statistical investigation of the ultracool dwarf companion distribution (spectral type M6 and later). Utilizing a Bayesian algorithm, I tested models of the companion distribution against data from an extensive set of space and ground-based imaging observations of nearby ultracool dwarfs. My main conclusions are f…
Host Dynamics and Origin of Palomar-Green QSOs
Lutz, D.; Genzel, R.; Sturm, E. +7 more
We present host galaxy velocity dispersions of 12 local (mainly Palomar-Green) QSOs measured directly from the stellar CO absorption features in the H band. The mean bulge dispersion of the QSOs in our sample is 186 km s-1 with a standard deviation of 24 km s-1. The measurement of the stellar dispersion in QSOs enables us to …
Hubble Space Telescope Parallaxes of AM CVn Stars and Astrophysical Consequences
Groot, P. J.; McArthur, B. E.; Benedict, G. F. +5 more
We present absolute parallaxes and relative proper motions for five AM CVn stars, which we obtained using the Fine Guidance Sensors on board the Hubble Space Telescope. Our parallax measurements translate into distances dAMCVn=606+135-93 pc, dHPLib=197+14-12 pc, dCRBoo=33…
The Gemini Deep Deep Survey. VIII. When Did Early-Type Galaxies Form?
Glazebrook, Karl; McCarthy, Patrick J.; Yan, Haojing +13 more
We have used the Hubble Space Telescope's Advanced Camera for Surveys (Ford et al. 2003) to measure the cumulative mass density in morphologically selected early-type galaxies over the redshift range 0.8<z<1.7. Our imaging data set covers four well-separated sight lines and is roughly intermediate (in terms of both depth and area) between th…
On the Progenitors of Two Type II-P Supernovae in the Virgo Cluster
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Foley, Ryan J. +3 more
Direct identification of the progenitors of supernovae (SNe) is rare because of the required spatial resolution and depth of the archival data prior to the SN explosions. Here we report on the identification of the progenitors of two nearby SNe in the Virgo Cluster: SN 2006my in NGC 4651 and SN 2006ov in M61. We obtained high-quality ground-based …