Search Publications
Phosphorus in the diffuse interstellar medium
Lebouteiller, V.; Ferlet, R.; Kuassivi
We present FUSE and HST/STIS measurements of the P ii column density toward Galactic stars. We analyzed P ii through the profile fitting of the unsaturated λ1125 and λ1533 lines and derived column densities integrated along the sightlines as well as in individual resolved components. We find that phosphorus is not depleted along those sightlines s…
Chandra Study of X-Ray Point Sources in the Early-Type Galaxy NGC 4552 (M89)
Kundu, Arunav; Xu, Haiguang; Zhang, Zhongli +3 more
We present a Chandra ACIS study of the early-type galaxy NGC 4552. We detect 47 X-ray point sources, most of which are likely low-mass X-ray binaries (LMXBs), within four effective radii (Re). The brightest X-ray source coincides with the optical, UV, and radio center of the galaxy and shows variability on >1 hr timescales, indicatin…
Tycho-2 stars with infrared excess in the MSX Point Source Catalogue
Lumsden, S. L.; Oudmaijer, R. D.; Clarke, A. J.
Stars of all evolutionary phases have been found to have excess infrared emission due to the presence of circumstellar material. To identify such stars, we have positionally correlated the infrared Mid-Course Space Experiment (MSX) Point Source Catalogue and the Tycho-2 optical catalogue. Near-mid-infrared colour criteria have been developed to se…
Submillimeter Array Observations of Disks in the SR 24 Multiple Star System
Andrews, Sean M.; Williams, Jonathan P.
We present high-resolution aperture synthesis images from the Submillimeter Array of the 225 GHz (1.3 mm) continuum and 12CO J=2-1 line emission from the disks around components of the hierarchical triple system SR 24, located in the Ophiuchus star-forming region. The most widely separated component, SR 24 S (with a projected semimajor …
Stellar Disks and Halos of Edge-on Spiral Galaxies: NGC 891, NGC 4144, and NGC 4244
Tikhonov, N. A.; Galazutdinova, O. A.
Stellar photometry of images from the ACS and WFPC2 cameras on the Hubble Space Telescope (HST) is used to study the star composition and spatial distribution of stars in three edge-on visible spiral galaxies: NGC 891, NGC 4144, and NGC 4244. Measurements of the surface number density of old stars revealed two stellar subsystems in these galaxies:…
A Search for Discrete X-Ray Spectral Features in a Sample of Bright γ-Ray Burst Afterglows
Sako, Masao; Harrison, Fiona A.; Rutledge, Robert E.
We present uniform, detailed spectral analyses of γ-ray burst (GRB) X-ray afterglows observed with ASCA, BeppoSAX, Chandra, and XMM-Newton and critically evaluate the statistical significances of X-ray emission and absorption features in these spectra. The sample consists of 21 X-ray afterglow observations up to and including that of GRB 040106 wi…
Massive elliptical galaxies in X-rays: The role of late gas accretion
Matteucci, F.; Kawata, D.; Gibson, B. K. +1 more
We present a new chemical evolution model meant to be a first step in the self-consistent study of both optical and X-ray properties of elliptical galaxies. Detailed cooling and heating processes in the interstellar medium (ISM) are taken into account using a mono-phase one-zone treatment which allows a more reliable modelling of the galactic wind…
Normal Nearby Galaxies
Tuffs, Richard J.; Popescu, Cristina C.; Sauvage, Marc
Following on from IRAS, ISO has provided a huge advancement in our knowledge of the phenomenology of the infrared (IR) emission of normal galaxies and the underlying physical processes. Highlights include the discovery of an extended cold dust emission component, present in all types of gas-rich galaxies and carrying the bulk of the dust luminosit…
X-rays from α Centauri - The darkening of the solar twin
Schmitt, J. H. M. M.; Robrade, J.; Favata, F.
We present first results from five XMM-Newton observations of the binary system α Centauri, which has been observed in snapshot like exposures of roughly two hours each during the last two years. In all our observations the X-ray emission of the system is dominated by α Cen B, a K1 star. The derived light curves of the individual components reveal…
X-ray synchrotron emission from the oblique shock in the jet of the powerful radio galaxy 3C346
Birkinshaw, M.; Worrall, D. M.
We report the first detection, with Chandra, of X-ray emission from the jet of the powerful narrow-line radio galaxy 3C346. X-rays are detected from the bright radio and optical knot at which the jet apparently bends by approximately 70°. The Chandra observation also reveals a bright galaxy-scale atmosphere within the previously known cluster and …