Search Publications
Discovery of CH and OH in the -513 km s-1 Ejecta of η Carinae
Gull, T. R.; Nielsen, K. E.; Bruhweiler, F. +3 more
The very massive star η Carinae (η Car) is enshrouded in an unusual complex of stellar ejecta, which is highly depleted in C and O and enriched in He and N. This circumstellar gas gives rise to distinct absorption components corresponding to at least 20 different velocities along the line of sight. The velocity component at -513 km s-1 …
Supersolar N/C in the Narrow-Line Seyfert 1 Galaxy Markarian 1044
Pogge, Richard W.; Nicastro, Fabrizio; Mathur, Smita +2 more
Narrow-line Seyfert 1 galaxies (NLS1s) are known to have extreme values of a number of properties compared to active galactic nuclei (AGNs) as a class. In particular, previous emission-line studies have suggested that NLS1s are unusually metal-rich compared to broad-line AGNs of comparable luminosity. We present low- and medium-resolution spectros…
An XMM-Newton Study of the Coronae of σ2 Coronae Borealis
Güdel, Manuel; Audard, Marc; Suh, Jin A. +1 more
We present results of XMM-Newton Guaranteed Time observations of the RS CVn binary σ2 Coronae Borealis. The spectra obtained with the Reflection Grating Spectrometers and the European Photon Imaging Camera MOS2 were simultaneously fitted with collisional ionization equilibrium plasma models to determine coronal abundances of various ele…
The Prominent Dust Emission Feature near 8.9 µm in Four H II Regions
Hayward, T. L.; Tielens, A. G. G. M.; Boogert, A. C. A. +2 more
We present a mid-infrared study of four H II regions based on the combination of Infrared Space Observatory (ISO) SWS observations with spatial information from SpectroCam-10 images and long-slit spectra. We report a prominent broad emission feature near 8.9 µm. The peak position and width of this feature do not resemble known polycyclic aro…
Molecular Hydrogen in Orion as Observed by the Far Ultraviolet Spectroscopic Explorer
France, K.; McCandliss, S. R.
Diffuse far-ultraviolet stellar emission scattered by dust grains has been observed in a region near the Orion Nebula. In addition to the scattered stellar continuum, emission and absorption features produced by molecular hydrogen have been identified. In this Letter, we present an analysis of this absorption and fluorescent emission from molecula…
A Multiwavelength Study of the X-Ray Sources in NGC 5018
Wu, Kinwah; Tennant, Allyn F.; Swartz, Douglas A. +2 more
The E3 giant elliptical galaxy NGC 5018 was observed with the Chandra X-Ray Observatory's Advanced CCD Imaging Spectrometer for 30 ks on 2001 April 14. Results of the analysis of these X-ray data as well as of complementary optical, infrared, and radio data are reported. Seven X-ray point sources, including the nucleus, were detected. If they are …
Helioseismic Ring Analyses of Artificial Data Computed for Two-dimensional Shearing Flows
Gough, Douglas; Thompson, Michael J.; Toomre, Juri +1 more
The local helioseismological technique of ring analysis has been crucial in the discovery of complex large-scale flows in the Sun's near-surface shear layer. However, current implementations of ring-analysis procedures assume that the flow field is horizontally homogeneous over the analysis region. This assumption is certainly incorrect, and in th…
XMM-Newton and Optical Follow-up Observations of Three New Polars from the Sloan Digital Sky Survey
Brinkmann, J.; Szkody, Paula; Schmidt, Gary D. +7 more
We report follow-up XMM-Newton and optical observations of three new polars found in the Sloan Digital Sky Survey. Simple modeling of the X-ray spectra, and consideration of the details of the X-ray and optical light curves corroborate the polar nature of these three systems and provide further insights into their accretion characteristics. During…
XMM-Newton Observations of Optically Selected Sloan Digital Sky Survey Clusters
Georgakakis, A.; Georgantopoulos, I.; Plionis, M. +1 more
We explore the X-ray properties of a subset of the optically selected Sloan Digital Sky Survey (SDSS) cluster sample of Goto et al. by analyzing seven public XMM-Newton pointings, with exposure times ranging from ~4 to 46 ks. There are in total 17 SDSS clusters out of which only eight are detected at X-ray wavelengths with f0.5-2keV>…
Colors of Luminous Bulges in Cluster MS 1054-03 and Field Galaxies at Redshifts z~0.83
Tran, Kim-Vy; Willmer, Christopher N. A.; Im, Myungshin +3 more
Using Hubble Space Telescope images, we separate the bulgelike (dubbed ``pbulge'') and disklike (``pdisk'') components of 71 galaxies in the rich cluster MS 1054-03 and of 21 in the field. Our key finding is that luminous pbulges are very red, with rest-frame U-B~0.45, while predicted colors are bluer by 0.20 mag. Moreover, these very red colors a…