Search Publications
On the Column Density of AGN Outflows: The Case of NGC 5548
Korista, Kirk T.; Arav, Nahum; de Kool, Martijn
We reanalyze the Hubble Space Telescope high-resolution spectroscopic data of the intrinsic absorber in NGC 5548 and find that the C IV absorption column density is at least 4 times larger than previously determined. This increase arises from accounting for the kinematical nature of the absorber and from our conclusion that the outflow does not co…
Molecular Gas and Nuclear Activity in Ultraluminous Infrared Galaxies with Double Nuclei
Sanders, D. B.; Surace, J. A.; Evans, A. S. +1 more
High-resolution CO(1-->0) observations of five ultraluminous infrared galaxies [ULIGs; LIR(8-1000µm)>~1012 Lsolar] with double nuclei are analyzed. These sources constitute a complete subset of local ULIGs expected to be in an intermediate stage of merging and are selected to have projected nuclear sepa…
Chandra Observations of Markarian 273: Unveiling the Central Active Galactic Nucleus and the Extended Hot Gas Halo
Xia, X. Y.; Xue, S. J.; Mao, S. +3 more
We report X-ray observations of the field containing the ultraluminous IRAS galaxy Mrk 273. The data were obtained using the Advanced CCD Imaging Spectrometer S3 instrument on board Chandra. The high-resolution X-ray image for the first time reveals a compact hard X-ray nucleus in Mrk 273. Its position is coincident with the northern nucleus ident…
A Far Ultraviolet Spectroscopic Explorer Survey of Late-Type Dwarf Stars
Ayres, Thomas R.; Redfield, Seth; Wood, Brian E. +5 more
We describe the 910-1180 Å spectra of seven late-type dwarf stars obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. The stars include Altair (A7 IV), Procyon (F5 IV-V), α Cen A (G2 V), AB Dor (K1 V), α Cen B (K2 V), ɛ Eri (K2 V), and AU Mic (M0 V). We present line identifications, fluxes, Doppler shifts, and widths. Dopple…
Evolution in the Far-Infrared Spectra of Low-Mass Young Embedded Sources
Giannini, Teresa; Nisini, Brunella; Lorenzetti, Dario
The far-infrared spectra (45-197 µm) of 28 low-luminosity young embedded objects have been studied in order to search for possible evolutive trends in the observed spectral features. The low-resolution spectra from 45 to 197 µm of 17 Class 0 and 11 Class I sources taken with the Long Wavelength Spectrometer (LWS) on board the Infrared …
Orbits of Four Very Massive Binaries in the R136 Cluster
Massey, Philip; Penny, Laura R.; Vukovich, Julia
We present radial velocity and photometry for four early-type, massive, double-lined spectroscopic binaries in the R136 cluster. Three of these systems are eclipsing, allowing orbital inclinations to be determined. One of these systems, R136-38 (O3 V+O6 V), has one of the highest masses ever measured for the primary, 57 Msolar. Comparis…
NICMOS Images of the GG Tauri Circumbinary Disk
Duchêne, G.; Ghez, A. M.; McCabe, C.
We present deep, near-infrared images of the circumbinary disk surrounding the pre-main-sequence binary star GG Tau A, obtained with NICMOS aboard the Hubble Space Telescope. The spatially resolved protoplanetary disk scatters ~1.5% of the stellar flux, with a near-side-to-far-side flux ratio of ~1.4, independent of wavelength, and colors that are…
The Effective Temperatures of Mid-O Stars
Bianchi, Luciana; Garcia, Miriam
We derived photospheric parameters, mass-loss rates, and wind velocities of Galactic O6-O7 stars by analyzing high-resolution spectra in the far-UV and UV ranges with line-blanketed, hydrodynamic, non-LTE spherical models. We combined spectra from the Far Ultraviolet Spectroscopic Explorer (FUSE) in the range 905-1187 Å and International Ultraviol…
A Far-Ultraviolet Survey of 47 Tucanae. I. Imaging
Zurek, David R.; Shara, Michael M.; Long, Knox S. +1 more
We present results from the imaging portion of a far-ultraviolet (FUV) survey of the core of 47 Tucanae. We have detected 767 FUV sources, 527 of which have optical counterparts in archival HST/WFPC2 images of the same field. Most of our FUV sources are main-sequence (MS) turnoff stars near the detection limit of our survey. However, the FUV/optic…
Rotation and Activity in the Solar-Metallicity Open Cluster NGC 2516
Pinsonneault, Marc; Sills, Alison; Jeffries, Robin D. +3 more
We report new measures of radial velocities and rotation rates (vsini) for 51 F and early G stars in the open cluster NGC 2516 and combine these with previously published data. From high signal-to-noise ratio spectra of two stars, we show that NGC 2516 has a relative iron abundance with respect to the Pleiades of Δ[Fe/H]=+0.04+/-0.07 at the canoni…