Search Publications
Missions
Journals
Publication Years
A photoionization-modelling study of 30 Doradus: the case for small-scale chemical inhomogeneity
Tsamis, Yiannis G.; Péquignot, Daniel
Photoionization models of the giant HII region (GHIIR) 30 Doradus are built and confronted to available ultraviolet (UV), optical, infrared (IR) [Infrared Space Observatory (ISO)] and radio spectra, under blackbody or CoStar spectral energy distributions for the primary source and various density distributions for the nebular gas. Chemically homog…
A possible association of the new VHE γ-ray source HESS J1825-137 with the pulsar wind nebula G18.0-0.7
Raux, J.; Ripken, J.; Funk, S. +96 more
We report on a possible association of the recently discovered very high-energy γ-ray source HESS J1825-137 with the pulsar wind nebula (commonly referred to as G 18.0 0.7) of the 2.1× 104 year old Vela-like pulsar PSR B1823 13. HESS J1825-137 was detected with a significance of 8.1σ in the Galactic Plane survey conducted with the HESS …
XMM-Newton observations of the Lockman Hole IV: spectra of the brightest AGN
Streblyanska, A.; Barcons, X.; Fabian, A. C. +5 more
This paper presents the results of a detailed X-ray spectral analysis of a sample of 123 X-ray sources detected with XMM-Newton in the Lockman Hole field. This is the deepest observation carried out with XMM-Newton with more that 600 ks of good EPIC-pn data. We have spectra with good signal to noise (>500 source counts) for all objects down to …
Dynamical Masses for Low-Mass Pre-Main-Sequence Stars: A Preliminary Physical Orbit for HD 98800 B
Torres, Guillermo; Latham, David W.; Wasserman, Lawrence H. +7 more
We report on Keck Interferometer observations of the double-lined binary (B) component of the quadruple pre-main-sequence (PMS) system HD 98800. With these interferometric observations, combined with astrometric measurements made by the Hubble Space Telescope (HST) Fine Guidance Sensors (FGS) and published radial velocity observations, we have est…
Chemical abundances in 43 metal-poor stars
Magain, P.; Gustafsson, B.; Asplund, M. +3 more
We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni, and Ba for 43 metal-poor field stars in the solar neighbourhood, most of them subgiants or turn-off-point stars with iron abundances [Fe/H] ranging from -0.4 to -3.0. About half of this sample has not been spectroscopically analysed in detail before. Effective temperatures…
Open flux estimates in Saturn's magnetosphere during the January 2004 Cassini-HST campaign, and implications for reconnection rates
Milan, S. E.; Badman, S. V.; Clarke, J. T. +4 more
During 8-30 January 2004, a sequence of 68 UV images of Saturn's southern aurora was obtained by the Hubble Space Telescope (HST), coordinated for the first time with measurements of the upstream interplanetary conditions made by the Cassini spacecraft. Using the poleward edge of the observed aurora as a proxy for the open-closed field line bounda…
Blue Luminous Stars in Nearby Galaxies: Quantitative Spectral Analysis of M33 B-Type Supergiant Stars
Smartt, S. J.; Lennon, D. J.; Herrero, A. +5 more
We present the detailed spectral analysis of a sample of M33 B-type supergiant stars, aimed at the determination of their fundamental parameters and chemical composition. The analysis is based on a grid of non-LTE metal line-blanketed model atmospheres including the effects of stellar winds and spherical extension computed with the code FASTWIND. …
Stellar and Total Mass in Early-Type Lensing Galaxies
Saha, Prasenjit; Ferreras, Ignacio; Williams, Liliya L. R.
For 18 well-observed gravitationally lensed QSOs, we compare new nonparametric mass profiles for the lensing galaxies with stellar population models derived from published Hubble Space Telescope photometry. The large volume of parameter space searched-with respect to the possible star formation histories-allows us to infer robust estimates and unc…
Constraints on the ionizing flux emitted by T Tauri stars
Clarke, C. J.; Pringle, J. E.; Alexander, R. D.
We present the results of an analysis of ultraviolet observations of T Tauri stars (TTs). By analysing emission measures taken from the literature, we derive rates of ionizing photons from the chromospheres of five classical TTs in the range ~1041-1044 photon s-1, although these values are subject to large uncertai…
A Chandra HETGS Spectral Study of the Iron K Bandpass in MCG -6-30-15: A Narrow View of the Broad Iron Line
Young, A. J.; Fabian, A. C.; Reynolds, C. S. +3 more
We present a high-resolution X-ray spectrum of the iron K bandpass in MCG -6-30-15 based on a 522 ks observation with Chandra's High Energy Transmission Grating Spectrometer (HETGS). The Chandra spectrum is consistent with the presence of a relativistically broadened, highly redshifted iron Kα emission line with a profile similar to previous obser…