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Testing Radiatively Inefficient Accretion Flow Theory: An XMM-Newton Observation of NGC 3998
Ptak, A.; Ho, L. C.; Terashima, Y. +1 more
We present the results of a 10 ks XMM-Newton observation of NGC 3998, a ``type I'' LINER galaxy (i.e., with significant broad Hα emission). Our goal is to test the extent to which radiatively inefficient accretion flow (RIAF) models and/or scaled-down active galactic nuclei (AGNs) models are consistent with the observed properties of NGC 3998. A p…
Resolving OB Systems in the Carina Nebula with the Hubble Space Telescope Fine Guidance Sensor
Gies, Douglas R.; Walborn, Nolan R.; Moffat, Anthony F. J. +4 more
We observed 23 OB stars in the Carina Nebula (NGC 3372) with the Hubble Space Telescope's Fine Guidance Sensor 1r (FGS1r) in its high angular resolution mode. Five of these OB stars are newly resolved binaries with projected separations ranging from 0.015" to 0.352" (37 to 880 AU at a distance of 2.5 kpc), and V-band magnitude differences ranging …
Cassini VIMS observations of the Galilean satellites including the VIMS calibration procedure
Sotin, C.; Brown, R. H.; Baines, K. H. +22 more
The Visual and Infrared Mapping Spectrometer (VIMS) observed the Galilean satellites during the Cassini spacecraft's 2000/2001 flyby of Jupiter, providing compositional and thermal information about their surfaces. The Cassini spacecraft approached the jovian system no closer than about 126 Jupiter radii, about 9 million kilometers, at a phase ang…
On the Determination of Michelson Doppler Imager High-Degree Mode Frequencies
Schou, J.; Korzennik, S. G.; Rabello-Soares, M. C.
The characteristics of the solar acoustic spectrum are such that mode lifetimes get shorter and spatial leaks get closer in frequency as the degree of a mode increases for a given order. A direct consequence of this property is that individual p-modes are resolved only at low and intermediate degrees and that at high degrees individual modes blend…
Radio detections of the neutron star X-ray binaries 4U 1820 - 30 and Ser X-1 in soft X-ray states
Homan, J.; van der Klis, M.; Fender, R. P. +4 more
We present the analysis of simultaneous X-ray (RXTE) and radio (VLA) observations of two atoll-type neutron star X-ray binaries: 4U 1820 - 30 and Ser X-1. Both sources were steadily in the soft (`banana') X-ray state during the observations. We have detected the radio counterpart of 4U 1820 - 30 at 4.86 and 8.46 GHz at a flux density of ~0.1 mJy. …
Mass Segregation in the Globular Cluster Palomar 5 and its Tidal Tails
Grebel, Eva K.; Caldwell, John A. R.; Koch, Andreas +2 more
We present the stellar main-sequence luminosity function (LF) of the disrupted, low-mass, low-concentration globular cluster Palomar 5 and its well-defined tidal tails, which emanate from the cluster as a result of its tidal interaction with the Milky Way. The results of our deep (B~24.5) wide-field photometry unequivocally indicate that preferent…
The distance to the Pleiades from orbital solution of the double-lined eclipsing binary HD 23642
Munari, U.; Soubiran, C.; Siviero, A. +3 more
Combining precise B, V photometry and radial velocities, we have been able to derive a firm orbital solution and accurate physical parameters for the newly discovered eclipsing binary HD 23642 in the Pleiades open cluster. The resulting distance to the binary and therefore to the cluster is 132 ± 2 pc. This closely confirms the distance modulus ob…
An XMM-Newton observation of Ark 120: the X-ray spectrum of a `bare' Seyfert 1 nucleus
Piro, L.; Vaughan, S.; Fabian, A. C. +3 more
We report on a long (100 ks) XMM-Newton observation of the bright Seyfert 1 galaxy Arakelian 120. The source previously showed no signs of intrinsic reddening in its infrared-ultraviolet continuum and previous observations had shown no evidence for ionized absorption in either the ultraviolet or X-ray bands. The new XMM-Newton Reflection Grating S…
Chemical abundances of planetary nebulae from optical recombination lines - I. Observations and plasma diagnostics
Liu, Y.; Barlow, M. J.; Liu, X. -W. +1 more
We have obtained deep optical spectra of medium resolution for a sample of 12 Galactic planetary nebulae (PNe). Optical recombination lines (ORLs) from carbon, nitrogen and oxygen have been detected in 11 of them and neon ORLs in nine of them. All spectra were obtained by scanning a long slit across the nebular surface, yielding relative line inte…
Stellar and Gaseous Abundances in M82
Maiolino, R.; Ranalli, P.; Comastri, A. +1 more
The near-infrared (near-IR) absorption spectra of starburst galaxies show several atomic and molecular lines from red supergiants that can be used to infer reliable stellar abundances. The metals locked in stars give a picture of the galaxy metallicity prior to the last burst of star formation. The enrichment of the new generation of stars born in…