Search Publications
M Dwarfs from Hubble Space Telescope Star Counts. III. The Groth Strip
Gould, Andrew; Bahcall, John N.; Flynn, Chris
We analyze the disk M dwarfs found in 31 new fields observed with the Wide Field Camera 2 (WFC2) on the Hubble Space Telescope, together with the sample previously analyzed from 22 WFC2 fields and 162 prerepair Planetary Camera 1 fields. The new observations, which include the 28 high-latitude fields comprising the Large Area Multi-Color Survey (G…
Triggered Star Formation in a Massive Galaxy at z = 3.8: 4C 41.17
Dey, Arjun; Vacca, William D.; van Breugel, Wil +1 more
We present deep spectropolarimetric observations obtained with the W. M. Keck Telescope of the very high redshift (z = 3.79786 +/- 0.0024) radio galaxy 4C 41.17. We find that the bright, spatially extended rest-frame UV continuum emission from this galaxy, which is aligned with the radio axis, is unpolarized (P2σ < 2.4%). This implie…
Ultraviolet Coronagraph Spectrometer Observations of Density Fluctuations in the Solar Wind
Romoli, M.; Poletto, G.; Noci, G. +2 more
Recent Ultraviolet Coronagraph Spectrometer (UVCS) white-light channel (WLC) observations on board the Solar and Heliospheric Observatory (SOHO) indicate quasi-periodic variations in the polarized brightness (pB) in the polar coronal holes. This is the first observation of possible signatures of compressional waves high above the limb (at heliocen…
Infrared Space Observatory Measurements of [C II] Line Variations in Galaxies
Helou, G.; Stacey, G.; Malhotra, S. +11 more
We report measurements of the [C II] fine-structure line at 157.714 µm in 30 normal star-forming galaxies with the Long Wavelength Spectrometer (LWS) on the Infrared Space Observatory (ISO). The ratio of the line to total far-infrared (FIR) luminosity, L[CII]/LFIR, measures the ratio of the cooling of gas to that of dus…
On the Evolutionary Phase and Mass Loss of the Wolf-Rayet--like Stars in R136a
Hubeny, Ivan; Heap, Sara R.; de Koter, Alex
We report on a systematic study of the most massive stars, in which we analyzed the spectra of four very luminous stars in the Large Magellanic Cloud. The stars lie in the 30 Doradus complex, three of which are located in the core of the compact cluster, R136a (R136a1, R136a3, and R136a5), and the fourth (Melnick 42), located about 8" north of R13…
Optical Rotation Curves of Distant Field Galaxies: Sub-L* Systems
Illingworth, Garth D.; Faber, S. M.; Gronwall, Caryl +6 more
Moderate-resolution spectroscopic observations from the Keck 10 m telescope are used to derive internal kinematics for eight faint disk galaxies in the fields flanking the Hubble Deep Field. The spectroscopic data are combined with high-resolution F814W Wide Field Planetary Camera 2 images from the Hubble Space Telescope that provide morphologies,…
Ellipticals with Kinematically Distinct Cores: V - I Color Images with WPFC2
Franx, Marijn; Illingworth, Garth D.; Forbes, Duncan A. +1 more
We have analyzed Hubble Space Telescope WFPC2 F555W and F814W (i.e., V and I) images for 15 elliptical galaxies with kinematically distinct cores. For each of them, we have derived surface brightness and isophotal parameter profiles in the two bands, color maps, and radial profiles in V - I. Most galaxies show patchy dust absorption close to their…
The Ultraviolet Properties of the Narrow-Line Quasar I Zw 1
Laor, Ari; Green, Richard F.; Jannuzi, Buell T. +1 more
I Zwicky 1 (I Zw 1) is the prototype narrow-line quasar. Its narrow-line profiles minimize blending effects and thus allow a significantly more accurate study of individual quasar emission lines. We report here the results of our study of the 1150-3250 Å emission of I Zw 1 using a high signal-to-noise (50-120) spectrum obtained with the Faint Obje…
The Nature of Compact Galaxies in the Hubble Deep Field. I. Global Properties1,
Illingworth, Garth D.; Faber, S. M.; Koo, David C. +5 more
We present 10 m Keck spectroscopy and photometry for a sample of 61 small (r1/2 <= 0.5"), faint (I814 <= 23.74), high-surface brightness (µI814 < 22.2 mag arcsec-2) galaxies in fields flanking the Hubble Deep Field. The majority of this empirically defined sample of compact galaxies lies a…
The Abundance of Interstellar Nitrogen
Sofia, Ulysses J.; Meyer, David M.; Cardelli, Jason A.
Using the Hubble Space Telescope Goddard High Resolution Spectrograph (GHRS), we have obtained high S/N echelle observations of the weak interstellar N I λλ1160, 1161 absorption doublet toward the stars γ Cas, λ Ori, ι Ori, κ Ori, δ Sco, and κ Sco. In combination with a previous GHRS measurement of N I toward ζ Oph, these new observations yield a …