Search Publications
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…
Mixed particle acceleration at CME-driven shocks and flares
Zank, G. P.; Li, G.
A recent study of Cane et al. [2003] showed that in some intense SEP events, the time-intensity profiles exhibit two peaks, with an earlier one having a high Fe/O and a later one with a low Fe/O ratio. They suggested that these two-component events are due to CMEs and their accompanying flares occurring together, with the first peak being flare-re…
Nightglow in the Upper Atmosphere of Mars and Implications for Atmospheric Transport
Bertaux, Jean-Loup; Leblanc, François; Perrier, Séverine +8 more
We detected light emissions in the nightside martian atmosphere with the SPICAM (spectroscopy for the investigation of the characteristics of the atmosphere of Mars) ultraviolet (UV) spectrometer on board the Mars Express. The UV spectrum of this nightglow is composed of hydrogen Lyman α emission (121.6 nanometers) and the γ and δ bands of nitric …
INTEGRAL discovery of persistent hard X-ray emission from the Soft Gamma-ray Repeater SGR 1806-20
Hurley, K.; Götz, D.; Mereghetti, S. +1 more
We report the discovery of persistent hard X-ray emission extending up to 150 keV from the soft gamma-ray repeater SGR 1806-20 using data obtained with the INTEGRAL satellite in 2003-2004. Previous observations of hard X-rays from objects of this class were limited to short duration bursts and rare transient episodes of strongly enhanced luminosit…
Kinematics of Low-z Ultraluminous Infrared Galaxies and Implications for Dynamical Mass Derivations in High-z Star-forming Galaxies
Arribas, Santiago; Colina, Luis; Monreal-Ibero, A.
The kinematic properties of the gaseous and stellar components of 11 ultraluminous infrared galaxies (ULIRGs; 14 nuclei) are investigated by means of integral field spectroscopy (IFS) with the INTEGRAL system and available IR and CO millimeter spectroscopy. The sample of ULIRGs cover different phases of the merging process and span all levels of a…
A Chandra X-ray survey of nearby dwarf starburst galaxies - II. Starburst properties and outflows
Ott, Jürgen; Walter, Fabian; Brinks, Elias
We present a comprehensive comparison of the X-ray properties of a sample of eight dwarf starburst galaxies observed with Chandra (IZw18, VIIZw403, NGC1569, NGC3077, NGC4214, NGC4449, NGC5253 and He2-10). In PaperI, we presented in detail the data reduction and analysis of the individual galaxies. For the unresolved X-ray sources, we find the foll…
X-ray reflection in the Seyfert galaxy 1H 0419-577 revealing strong relativistic effects in the vicinity of a Kerr black hole
Iwasawa, K.; Fabian, A. C.; Miniutti, G. +1 more
We report results obtained from six XMM-Newton observations of the Seyfert galaxy 1H 0419-577. The source was observed in a wide range of different flux levels, allowing its long-term spectral variability to be studied in detail, as already reported recently by Pounds et al. Here we show that the X-ray spectrum is well described by a simple two-co…