Search Publications
Homogenization of the Stellar Population along Late-Type Spiral Galaxies
dos Anjos, S.; Gadotti, D. A.
We present a study of the broadband UBV color profiles for 257 Sbc barred and nonbarred galaxies, using photoelectric aperture photometry data from the literature. Using robust statistical methods, we have estimated the color gradients of the galaxies, as well as the total and bulge mean colors. A comparative photometric study using CCD images was…
Damped Lyα Absorption from a Nearby Low Surface Brightness Galaxy
Bowen, David V.; Tripp, Todd M.; Jenkins, Edward B.
Ground-based and Hubble Space Telescope (HST) images of the nearby galaxy SBS 1543+593 (z=0.009) show it to be a low surface brightness (LSB) galaxy with a central surface brightness µB(0)=23.2 mag arcsec-2 and scale length 0.9 h-1100 kpc, values typical for the local LSB galaxy population. The gal…
Variable Stars in the Unusual, Metal-Rich, Globular Cluster NGC 6441
Pritzl, Barton J.; Smith, Horace A.; Sweigart, Allen V. +1 more
We have undertaken a search for variable stars in the metal-rich globular cluster NGC 6441 using time-series BV photometry. The total number of variables found near NGC 6441 has been increased to ~104, with 48 new variables being found in this survey. A significant number of the variables are RR Lyrae stars (~46), most of which are probable cluste…
A Dynamical Mass Constraint for Pre-Main-Sequence Evolutionary Tracks: The Binary NTT 045251+3016
Latham, David W.; Mazeh, Tsevi; Prato, L. +6 more
We present an astrometric-spectroscopic orbital solution for the pre-main-sequence binary NTT 045251+3016. Interferometric observations with the HST Fine Guidance Sensor No. 3 allowed stellar separations as small as 14 mas to be measured. Optical spectra provided 58 radial velocity measurements of the primary star, and near-infrared spectra provid…
The M31 Globular Cluster Luminosity Function
Brodie, Jean P.; Huchra, John P.; Barmby, Pauline
We combine our compilation of photometry of M31 globular clusters and probable cluster candidates with new near-infrared photometry for 30 objects. Using these data we determine the globular cluster luminosity function (GCLF) in multiple filters for the M31 halo clusters. We find a GCLF peak and dispersion V00=16.84+/-0.11, σ…
The Proper Motion of the Globular Cluster NGC 6553 and of Bulge Stars with the Hubble Space Telescope
Zoccali, M.; Bica, E.; Barbuy, B. +2 more
WFPC2 images obtained with the Hubble Space Telescope (HST) 4.16 years apart have allowed us to measure the proper motion of the metal-rich globular cluster NGC 6553 with respect to the background bulge stars. With a space velocity of (Π, Θ, W)=(-3.5, 230, -3) km s-1, NGC 6553 follows the mean rotation of both disk and bulge stars at a …
High-Velocity Cloud Complex C: Galactic Fuel or Galactic Waste?
Shull, J. Michael; Stocke, John T.; Gibson, Brad K. +3 more
We present HST Goddard High Resolution Spectrograph and Space Telescope Imaging Spectrograph observations of five quasi stellar objects that probe the prominent high-velocity cloud (HVC) Complex C, covering ~10% of the northern sky. Based upon a single sight-line measurement (Mrk 290), a metallicity [S/H]=-1.05+/-0.12 has been associated with Comp…
Hubble Space Telescope NICMOS Detection of a Partially Embedded, Intermediate-Mass, Pre-Main-Sequence Population in the 30 Doradus Nebula
Walborn, Nolan R.; Grebel, Eva K.; Brandner, Wolfgang +2 more
We present the detection of an intermediate-mass, pre-main-sequence population embedded in the nebular filaments surrounding the 30 Doradus region in the Large Magellanic Cloud (LMC) using HST/NICMOS. In addition to four previously known luminous Class I infrared ``protostars,'' the NICMOS data reveal 20 new sources with intrinsic infrared excess …
Optical and Near-Infrared Imaging of Infrared-Excess Palomar-Green Quasars
Sanders, D. B.; Evans, A. S.; Surace, Jason A.
Ground-based high spatial resolution (FWHM<0.3"-0.8") optical and near-infrared imaging (0.4-2.2 µm) is presented for a complete sample of optically selected Palomar-Green QSOs with far-infrared excesses at least as great as those of ``warm'' AGN-like ultraluminous infrared galaxies (Lir/LBBB>0.46). In all cases, …
Hubble Space Telescope NICMOS Spectroscopy of Charon's Leading and Trailing Hemispheres
Schneider, Glenn; Dumas, Christophe; Terrile, Richard J. +2 more
We used the near-infrared camera and multiobject spectrometer NICMOS on the Hubble Space Telescope to obtain 1.1-2.4 µm, low-resolution (R~200) slitless grism spectrophotometry of the individual members of the Pluto-Charon system. Water ice is present in its crystalline state on both the leading and trailing hemispheres of Charon. A 2.21 &mi…