Search Publications
Multiwavelength cosmological simulations of elliptical galaxies
Kawata, D.; Gibson, B. K.
We study the chemodynamical evolution of elliptical galaxies and their X-ray and optical properties using high-resolution cosmological simulations. Our tree N-body/smoothed particle hydrodynamics (SPH) code includes a self-consistent treatment of radiative cooling, star formation, supernovae feedback and chemical enrichment. We present a series of…
Modeling gas-phase H2O between 5 µ m and 540 µ m toward massive protostars
van Dishoeck, E. F.; Bergin, E. A.; Melnick, G. J. +4 more
We present models and observations of gas-phase H2O lines between 5 and 540 mu m toward deeply embedded massive protostars, involving both pure rotational and ro-vibrational transitions. The data have been obtained for 6 sources with both the Short and Long Wavelength Spectrometers (SWS and LWS) on board the Infrared Space Observatory (…
The circumstellar envelope of the C-rich post-AGB star HD 56126
Waters, L. B. F. M.; Hony, S.; de Koter, A. +1 more
We present a detailed study of the circumstellar envelope of the post-asymptotic giant branch ``21 mu m object'' HD 56126. We build a detailed dust radiative transfer model of the circumstellar envelope in order to derive the dust composition and mass, and the mass-loss history of the star. To model the emission of the dust we use amorphous carbon…
Revisiting the solid HDO/H2O abundances
Dartois, E.; Geballe, T. R.; d'Hendecourt, L. +3 more
We revisit the reported detection and upper limits on HDO in ice mantles present in the molecular cloud environments of the massive young protostars Gl 2136 and W33 A, using independent VLT-ISAAC and UKIRT-CGS4 spectroscopic observations. We also present VLT and UKIRT spectra of RAFGL 7009 near the HDO absorption wavelength and reanalyze the ISO-S…
The Star Formation History of NGC 1705: A Poststarburst Galaxy on the Verge of Activity
Leitherer, Claus; Greggio, L.; Tosi, M. +2 more
We infer the star formation history in different regions of the blue compact dwarf NGC 1705 by comparing synthetic color-magnitude diagrams with the Hubble Space Telescope optical and near-infrared photometry. We find that NGC 1705 is not a young galaxy, because its star formation commenced at least 5 Gyr ago. On the other hand, we confirm the exi…
A Comprehensive Study of the L1551 IRS 5 Binary System
Hartmann, Lee; Calvet, Nuria; Muzerolle, James +2 more
We model the Class I source L1551 IRS 5, adopting a flattened infalling envelope surrounding a binary disk system and a circumbinary disk. With our composite model, we calculate self-consistently the spectral energy distribution of each component of the L1551 IRS 5 system, using additional constraints from recent observations by ISO, the water ice…
GRB 011121: A Collimated Outflow into Wind-blown Surroundings
Mitrofanov, I.; Pian, E.; Palazzi, E. +31 more
We report optical and near-infrared follow-up observations of GRB 011121 collected predominantly at ESO telescopes in Chile. We discover a break in the afterglow light curve after 1.3 days, which implies an initial jet opening angle of about 9°. The jet origin of this break is supported by the fact that the spectral energy distribution is achromat…
An XMM-Newton observation of IGR J16320-4751 = AX J1631.9-4752
Tomsick, J. A.; Rodriguez, J.; Walter, R. +4 more
The hard X-ray sensitivity and arcminute position accuracy of the recently launched International Gamma-Ray Laboratory (INTEGRAL) has lead to the (re-)discovery of a class of heavily absorbed hard X-ray sources lying in the Galactic plane. We report on the analysis of an XMM observation of such a source IGR J16320-4751 = AX J1631.9-4752. Our analy…
Twenty-three cycles of changing open solar magnetic flux
Lockwood, M.
This paper presents a comparison of various estimates of the open solar flux, deduced from measurements of the interplanetary magnetic field, from the aa geomagnetic index and from photospheric magnetic field observations. The first two of these estimates are made using the Ulysses discovery that the radial heliospheric field is approximately inde…
The X-Ray-faint Emission of the Supermassive Nuclear Black Hole of IC 1459
Zezas, A.; Elvis, M.; Pellegrini, S. +6 more
Chandra observations of the supermassive black hole in the nucleus of IC 1459 show a weak (LX=8×1040 ergs s-1, 0.3-8 keV), unabsorbed nuclear X-ray source, with a slope Γ=1.88+/-0.09, and no strong Fe K line at 6.4 keV (EW<382 eV). This describes a normal active galactic nucleus (AGN) X-ray spectrum but lies at …