Search Publications
The Local Stellar Velocity Field via Vector Spherical Harmonics
Makarov, V. V.; Murphy, D. W.
We analyze the local field of stellar tangential velocities for a sample of 42,339 nonbinary Hipparcos stars with accurate parallaxes, using a vector spherical harmonic formalism. We derive simple relations between the parameters of the classical linear model (Ogorodnikov-Milne) of the local systemic field and low-degree terms of the general vecto…
Determination of the Physical Conditions of the Knots in the Helix Nebula from Optical and Infrared Observations
O'Dell, C. R.; Henney, W. J.; Ferland, G. J.
We use new Hubble Space Telescope and archived images to clarify the nature of the ubiquitous knots in the Helix Nebula, which are variously estimated to contain a significant to majority fraction of the material ejected by its central star. We employ published far-infrared spectrophotometry and existing 2.12 µm images to establish that the …
The Faint End of the Luminosity Function in the Core of the Coma Cluster
Kavelaars, J. J.; Gwyn, Stephen D. J.; Harris, William E. +4 more
We present optical measurements of the faint end of the luminosity function in the core of the Coma Cluster. Dwarf galaxies are detected down to a limiting magnitude of R~25.75 in images taken with the Hubble Space Telescope. This represents the faintest determination of the Coma luminosity function to date. With the assumption that errors due to …
Supernova Remnants in the Magellanic Clouds. IX. Multiwavelength Analysis of the Physical Structure of N49
Gruendl, R. A.; Chu, Y. -H.; Bilikova, J. +2 more
We present a multiwavelength analysis of the supernova remnant N49 in the Large Magellanic Cloud. Using high-resolution Hubble Space Telescope WFPC2 images of Hα, [S II], and [O III] emission, we study the morphology of the remnant and calculate the rms electron densities in different regions. We detect an offset of [O III] and Hα emission peaks o…
NACO-SDI Direct Imaging Search for the Exoplanet ɛ Eri b
Henning, Thomas; Reffert, Sabine; Brandner, Wolfgang +13 more
The active K2 V star ɛ Eri hosts the nearest known extrasolar planet. With an angular separation of about 1" on average, and an age of a few to several hundred megayears, ɛ Eri b is one of the prime candidates for becoming the first definitive extrasolar planet imaged directly. We present a multiepoch deep differential imaging survey performed wit…
Multiwavelength Study of Young Massive Star Clusters in the Interacting Galaxy Arp 24
Wu, Hong; Cao, Chen
We made a multiwavelength study of young massive star clusters (YSCs) in the interacting galaxy Arp 24 using optical and ultraviolet images from the Hubble Space Telescope (HST), the Sloan Digital Sky Survey, and the Galaxy Evolution Explorer, mid-infrared images from the Spitzer Space Telescope, and narrowband Hα images and optical spectra from t…
The Intermediate-Age Globular Cluster NGC 1783 in the Large Magellanic Cloud
Mucciarelli, Alessio; Ferraro, Francesco R.; Origlia, Livia
We present Hubble Space Telescope ACS deep photometry of the intermediate-age globular cluster NGC 1783 in the Large Magellanic Cloud. By using this photometric data set, we have determined the degree of ellipticity of the cluster (epsilon = 0.14 ± 0.03) and the radial density profile. This profile is well reproduced by a standard King model with …
BVI Photometry and the Luminosity Functions of the Globular Cluster M92
Sarajedini, Ata; Chaboyer, Brian; Paust, Nathaniel E. Q.
We present new BVI ground-based photometry and VI space-based photometry for the globular cluster M92 (NGC 6341) and examine luminosity functions in B, V, and I containing over 50,000 stars ranging from the tip of the red giant branch to several magnitudes below the main-sequence turnoff. Once corrected for completeness, the observed luminosity fu…
Star Formation, Radio Sources, Cooling X-Ray Gas, and Galaxy Interactions in the Brightest Cluster Galaxy in 2A0335+096
O'Dea, Christopher P.; Donahue, Megan; Voit, G. Mark +2 more
We present deep emission-line imaging taken with the new SOAR Optical Imager of the brightest cluster galaxy (BCG) in the nearby (z=0.035) X-ray cluster of galaxies 2A0335+096. We also present our analysis of additional, multiwavelength observations for the BCG, including long-slit optical spectroscopy, archival VLA radio data, Chandra X-ray imagi…
J- and Ks-Band Galaxy Counts and Color Distributions in the AKARI North Ecliptic Pole Field
Oyabu, Shinki; Matsuhara, Hideo; Takagi, Toshinobu +5 more
We present the J- and Ks-band galaxy counts and galaxy colors covering 750 arcmin2 in the deep AKARI north ecliptic pole (NEP) field, using the Florida Multi-object Imaging Near-IR Grism Observational Spectrometer on the Kitt Peak National Observatory 2.1 m telescope. The limiting magnitudes with a signal-to-noise ratio of 3 …