Search Publications
A Hubble Space Telescope Census of Nuclear Star Clusters in Late-Type Spiral Galaxies. II. Cluster Sizes and Structural Parameter Correlations
Böker, Torsten; Ho, Luis C.; Shields, Joseph C. +4 more
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 order to determine their effective radii after correction for the instrumental point-spread function. We use the results of this analysis to compare t…
Hubble Space Telescope Absolute Spectrophotometry of Vega from the Far-Ultraviolet to the Infrared
Bohlin, R. C.; Gilliland, R. L.
The Space Telescope Imaging Spectrograph (STIS) has measured the absolute flux for Vega from 0.17-1.01 µm on the Hubble Space Telescope white dwarf (WD) flux scale. These data are saturated by up to a factor of 80 overexposure but retain linearity to a precision of 0.2% because the charge bleeds along the columns and is recovered during read…
The Chemical Composition Contrast between M3 and M13 Revisited: New Abundances for 28 Giant Stars in M3
Guhathakurta, Puragra; Sneden, Christopher; Peterson, Ruth C. +2 more
We report new chemical abundances of 23 bright red giant members of the globular cluster M3, based on high-resolution (R~45,000) spectra obtained with the Keck I telescope. The observations, which involve the use of multislits in the HIRES Keck I spectrograph, are described in detail. Combining these data with a previously reported small sample of…
A Large Sample of Spectroscopic Redshifts in the ACS-GOODS Region of the Hubble Deep Field North
Capak, P.; Barger, A. J.; Cowie, L. L. +2 more
We report the results of an extensive spectroscopic survey of galaxies in the roughly 160 arcmin2 ACS-GOODS region surrounding the Hubble Deep Field North (HDF-N). We have identified 892 galaxies or stars with z'<24, R<24.5, or B<25 in the region. The spectra were obtained with either the DEIMOS or LRIS spectrographs…
The Globular Cluster Systems of the Early-Type Galaxies NGC 3379, NGC 4406, and NGC 4594 and Implications for Galaxy Formation
Zepf, Stephen E.; Rhode, Katherine L.
We have investigated the global properties of the globular cluster (GC) systems of three early-type galaxies: the Virgo Cluster elliptical NGC 4406, the field elliptical NGC 3379, and the field S0 galaxy NGC 4594. These galaxies were observed as part of a wide-field CCD survey of the GC populations of a large sample of normal galaxies beyond the L…
Do We Know of Any Maunder Minimum Stars?
Wright, J. T.
Most stars previously identified as Maunder minimum stars are old and evolved off the main sequence. Analysis of activity measurements from the California and Carnegie Planet Search program stars and Hipparcos parallaxes implies that the canonical relation between age and chromospheric activity breaks down for stars older than ~6 Gyr when activity…
Chandra and XMM-Newton Observations of RDCS 1252.9-2927, A Massive Cluster at z=1.24
Demarco, R.; Lidman, C.; Tozzi, P. +10 more
We present deep Chandra and XMM-Newton observations of the galaxy cluster RDCS 1252.9-2927, which was selected from the ROSAT Deep Cluster Survey (RDCS) and confirmed by extensive spectroscopy with the Very Large Telescope at redshift z=1.237. With the Chandra data, the X-ray emission from the intracluster medium is well resolved and traced out to…
An Astrometric Calibration of the MV-Porb Relationship for Cataclysmic Variables based on Hubble Space Telescope Fine Guidance Sensor Parallaxes
Harrison, Thomas E.; Johnson, Joni J.; McArthur, B. E. +4 more
We present new, high-precision astrometric parallaxes for three cataclysmic variables: WZ Saggitae, YZ Cancri, and RU Pegasi, obtained using the Fine Guidance Sensors on the Hubble Space Telescope. The addition of these three parallaxes to the existing data set allows us to examine the outburst luminosities for dwarf novae spanning the orbital per…
The Initial Mass Function and Stellar Content of NGC 3603
Bessell, Michael S.; Sung, Hwankyung
We present UBVRI and Hα photometry of the extremely compact, starburst cluster NGC 3603. Ground-based images, Hubble Space Telescope (HST) archival data, as well as Chandra X-ray data have been used for this study. We present, for the first time, optical color-magnitude diagrams (CMDs) for the stars in the cluster core down to V=22 mag. A well-def…
Hubble Space Telescope Imaging of HD 44179, The Red Rectangle
Gull, T. R.; Bond, Howard E.; Van Winckel, Hans +1 more
We present Hubble Space Telescope (HST) Wide Field Planetary Camera 2 and deep ground-based images of the Red Rectangle (RR), a bipolar proto-planetary nebula associated with the post-AGB binary system HD 44179. The high-resolution HST images reveal complex new structures, many of them unique to this object. The RR nebula is dominated by a discont…