Search Publications
Deep Hubble Space Telescope WFPC2 Photometry of M31's Thick Disk (?)
Sarajedini, Ata; Van Duyne, Jeffrey
We present deep color-magnitude diagrams (CMDs) for a field along the outer disk of M31 based on archival Hubble Space Telescope Wide Field Planetary Camera 2 observations in the F555W (~V) and F814W (~I) filters. The CMDs, which contain a total of about 50,000 stars, feature a prominent red giant branch (RGB) along with a significant population o…
Host Galaxies, Obscuration, and Nuclear Structure of Three Nearby Compact Symmetric Objects
Perlman, Eric S.; Stocke, John T.; Conway, John +1 more
We present three-band Hubble Space Telescope imaging of three nearby (z<=0.1) compact symmetric objects: 4C 31.04, 1946+708, and 1146+596. These objects were chosen on the basis of proximity to Earth as well as H I 21 cm line absorption. The inner H-band isophotes of these galaxies are well fitted by Nuker models, typical of nearby elliptical g…
A Detailed Analysis of a Cygnus Loop Shock-Cloud Interaction
Blair, William P.; Danforth, Charles W.; Raymond, John C.
The XA region of the Cygnus Loop is a complex zone of radiative and nonradiatve shocks interacting with interstellar clouds. We combine five far ultraviolet spectral observations from the Hopkins Ultraviolet Telescope (HUT), a grid of 24 IUE spectra, and a high-resolution long-slit Hα spectrum to study the spatial emission line variations across t…
Horizontal-Branch Morphology and Dense Environments: Hubble Space Telescope Observations of Globular Clusters NGC 2298, 5897, 6535, and 6626
Testa, Vincenzo; Iannicola, Giacinto; Buonanno, Roberto +4 more
HST observations of the core of four galactic globular clusters allowed us to obtain interesting clues about the influence of the environment on the star distribution along the horizontal branch. The chemical composition and the age of the target clusters have been derived through a detailed analysis of the (V,V-I) color-magnitude diagrams. The ph…
CCD Speckle Observations of Binary Stars from the Southern Hemisphere. III. Differential Photometry
Franz, Otto G.; Horch, Elliott; Ninkov, Zoran
Two hundred seventy-two magnitude difference measures of 135 double star systems are presented. The results are derived from speckle observations using the Bessel V and R passbands and a fast readout CCD camera. Observations were taken at two 60 cm telescopes, namely the Helen Sawyer Hogg Telescope, formerly at Las Campanas, Chile, and the Lowell-…
RX J0848+4456: Disentangling a Moderate Redshift Cluster
Papovich, C.; Tozzi, P.; Rosati, P. +7 more
We present a multiwavelength study of RX J0848+4456, a cluster of galaxies discovered through X-ray emission in the ROSAT Deep Cluster Survey. Our observations consist of WFPC2 imaging, optical spectra, and X-ray data collected with the Chandra X-Ray Observatory. We find that RX J0848+4456 consists of an X-ray-emitting cluster of galaxies at a red…
Caltech Faint Galaxy Redshift Survey. XV. Classifications of Galaxies with 0.2<Z<1.1 in the Hubble Deep Field North and its Flanking Fields
Cohen, Judith G.; van den Bergh, Sidney; Crabbe, Christopher
To circumvent the spatial effects of resolution on galaxy classification, the images of 233 objects of known redshift in the Hubble Deep Field (HDF) and its flanking fields that have redshifts in the range 0.20<z<1.10 were degraded to the resolution that they would have had if they were all located at a redshift of z=1.00. As in Paper XIV of…
The Main-Sequence Luminosity Function of Palomar 5 from THE HUBBLE SPACE TELESCOPE
Smith, Graeme H.; Grillmair, Carl J.
A low mass, large core radius, low central concentration, and strong tidal tails suggest that the globular cluster Palomar 5 has lost a large fraction of its initial mass over time. If the dynamical evolution of Pal 5 has been dominated by the effects of mass loss, then theoretical arguments suggest that the luminosity function should be deficient…
Hubble Space Telescope Images of the Ultraluminous Supernova Remnant Complex in NGC 6946
Blair, William P.; Fesen, Robert A.; Schlegel, Eric M.
We present Hubble Space Telescope (HST) narrow-passband Hα and [S II] images and broadband continuum images of the region around an extremely luminous optical and X-ray supernova remnant complex in the spiral galaxy NGC 6946. These images, obtained with the PC1 CCD of the Wide Field Planetary Camera 2, show a circular, limb-brightened shell of dia…
The Massive Star Content of NGC 6822: Ground-Based andHubble Space Telescope Photometry
Massey, Philip; Bianchi, Luciana; Romaniello, Martino +1 more
We investigate the massive star population of NGC 6822 with ground-based UBV photometry covering the whole of the galaxy and HST WFPC2 photometry with filters F255W, F336W, F439W, and F555W of two fields containing very rich and crowded OB associations. The four-band WFPC2 photometry is used to derive Teff and E(B-V). H-R diagrams are c…