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A Spectroscopic Survey of the Galaxy Cluster CL 1358+62 at Z = 0.328
Franx, Marijn; van Dokkum, Pieter; Fisher, David +1 more
We present a spectroscopic survey of the rich X-ray-selected galaxy cluster CL 1358+6245 at z = 0.328. When our 173 new multislit spectra of cluster galaxies are combined with data from the literature, we produce a catalog of 232 cluster members in a region 10' × 11' (3.5 Mpc × 3.8 Mpc) surrounding the brightest cluster galaxy. These data are used…
Hubble Space Telescope V-Band Imaging of the Bipolar Proto-Planetary Nebula IRAS 17150-3224
Kwok, Sun; Hrivnak, Bruce J.; Su, Kate Y. L.
We report Hubble Space Telescope Wide Field Planetary Camera 2 imaging of the bipolar proto-planetary nebula IRAS 17150-3224. We find a series of concentric arcs superposed on the two reflection nebular lobes, similar to those observed in AFGL 2688. This suggests that periodic mass-loss enhancement is a common phenomenon in the asymptotic giant br…
A Protocometary Cloud around HR 4796A?
Telesco, C.; Malkan, M.; Fisher, R. S. +3 more
We report both ROSAT observations and ground-based 10.8 µm imaging of the wide binary HR 4796, which consists of a main-sequence A-type star with a large amount of circumstellar dust, HR 4796A, and, at a separation of 7.7", a pre-main-sequence M-type companion, HR 4796B. From the ROSAT data, we find that the X-ray emission is centered on HR …
The Luminosity Function of the Globular Cluster NGC 6397 near the Limit of Hydrogen Burning
Anderson, Jay; Piotto, Giampaolo; Cool, Adrienne M. +1 more
Second-epoch Hubble Space Telescope observations of NGC 6397 have led to the measurement of proper motions accurate enough to separate the faintest cluster stars from the field, thus extending the luminosity function of this globular cluster far enough to approach the limit of hydrogen burning on the main sequence. We isolate a sample of 1385 main…
Strömgren Photometry of Globular Clusters: The Distance and Age of M13, Evidence for Two Populations of Horizontal-Branch Stars
Grundahl, Frank; VandenBerg, Don A.; Andersen, Michael I.
We present deep CCD photometry of the globular cluster M13 (NGC 6205) in the Strömgren uvbyβ system and determine a foreground reddening of E(b-y)=0.015+/-0.01 mag. From a fit to the main sequence of metal-poor subdwarfs with Hipparcos parallaxes, we derive (m-M)0=14.38+/-0.10, which implies an age near 12 Gyr assuming [Fe/H] = -1.61 an…
HIPPARCOS Parallaxes and the Cepheid Distance Scale
Madore, Barry F.; Freedman, Wendy L.
Hipparcos parallaxes have recently become available for a sample of Galactic Cepheids, and we have used these new distances to calibrate the Cepheid period-luminosity (PL) relation at six wavelengths (BVIJHK). Comparing these calibrations with previously published multiwavelength PL relations we find agreement to within 0.07 +/- 0.14 mag, or 4% +/…
Jet-Driven Motions in the Narrow-Line Region of NGC 1068
Marconi, A.; Macchetto, F. D.; Capetti, A. +3 more
We have obtained Hubble Space Telescope Faint Object Camera (FOC) f/48 long-slit spectroscopy of the inner 4" of the narrow-line region (NLR) of NGC 1068 between 3500 and 5400 Å with a spectral resolution of 1.78 Å pixel-1. At a spatial scale of 0.0287" pixel-1 these data provide an order-of-magnitude improvement in resolutio…
The Extragalactic Distance Scale Key Project. XVI. Cepheid Variables in an Inner Field of M101
Kelson, Daniel D.; Illingworth, Garth D.; Huchra, John P. +20 more
We report on the identification of 255 candidate variable stars in a field located some 1.7 arcmin from the center of the late-type spiral galaxy M101 = NGC 5457, based on observations made with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope. Photometric measurements in the F555W and F814W filters--analyzed independently…
Clustering at High Redshift: Precise Constraints from a Deep, Wide-Area Survey
Lauer, Tod R.; Oegerle, William; Postman, Marc +1 more
We present constraints on the evolution of large-scale structure from a catalog of 710,000 galaxies with IAB <= 24 derived from a KPNO 4 m CCD imaging survey of a contiguous 4° × 4° region. The advantage of using large contiguous surveys for measuring clustering properties on even modest angular scales is substantial: the effects of …
Galactic Cosmic-Ray Confinement Time: Ulysses High Energy Telescope Measurements of the Secondary Radionuclide 10Be
Connell, J. J.
We report new measurements of the isotopic abundances of the Galactic cosmic-ray isotopes 7Be, 9Be, and radioactive 10Be. These measurements from the Ulysses High Energy Telescope (HET) combine exceptional mass resolution with superior statistics. Measurements of radioisotopes produced as secondaries during cosmic-…