Search Publications
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…
The Discovery of Circumstellar Arcs around Two Bipolar Proto-planetary Nebulae
Kwok, Sun; Hrivnak, Bruce J.; Su, Kate Y. L.
Circumstellar arcs have been discovered using the Hubble Space Telescope in two proto-planetary nebulae (PPNs), IRAS 16594-4656, and IRAS 20028+3910. This raises to five the number of PPNs in which such arcs have been detected and suggests that they are not rare and may even be common features. All five of these PPNs display a bipolar morphology, …
The Nuclear Cusp Slopes of Dwarf Elliptical Galaxies
Ferguson, Henry C.; Mack, Jennifer; Stiavelli, Massimo +3 more
We derive the light profiles for a sample of 25 dwarf elliptical galaxies observed by us with Hubble Space Telescope's Wide Field and Planetary Camera 2 in F555W and F814W. These profiles are fitted with Nuker, R1/4, exponential, and Sersic laws and are also used to derive the nuclear cusp slopes γ. We discuss the correlation of nuclear…
Star Formation History in the Solar Vicinity
Bertelli, G.; Nasi, E.
The star formation history in the solar neighborhood is inferred by comparing a sample of field stars from the Hipparcos catalog with synthetic color-magnitude diagrams. We consider separately the main sequence and the red giant region of the H-R diagram. The criteria for our best solutions are based on the χ2 minimization of star distr…
Kinematics of the Narrow-Line Region in the Seyfert 2 Galaxy Markarian 3
Gull, T. R.; Kraemer, S. B.; Crenshaw, D. M. +5 more
We present measurements of radial velocities for the narrow-line region gas in the Seyfert 2 galaxy Mrk 3 out to ~1 kpc from the nucleus. The observations consist of two data sets, both using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope: (1) an [O III] slitless spectrum with the G430M grating of the inner 3" around …