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High-Resolution X-ray Imaging of a Globular Cluster Core: Compact Binaries in 47Tuc
Heinke, Craig; Murray, Stephen S.; Edmonds, Peter D. +1 more
We have obtained high-resolution (<~1'') deep x-ray images of the globular cluster 47Tucanae (NGC 104) with the Chandra X-ray Observatory to study the population of compact binaries in the high stellar density core. A 70-kilosecond exposure of the cluster reveals a centrally concentrated population of faint (Lx ~ 1030-33 e…
EXPORT: Spectral classification and projected rotational velocities of Vega-type and pre-main sequence stars
Rauer, H.; Schneider, J.; Eiroa, C. +19 more
In this paper we present the first comprehensive results extracted from the spectroscopic campaigns carried out by the EXPORT (EXoPlanetary Observational Research Team) consortium. During 1998-1999, EXPORT carried out an intensive observational effort in the framework of the origin and evolution of protoplanetary systems in order to obtain clues o…
delta Scuti and related stars: Analysis of the R00 Catalogue
Rodríguez, E.; Breger, M.
We present a comprehensive analysis of the properties of the pulsating delta Scuti and related variables based mainly on the content of the recently published catalogue by Rodríguez et al. (\cite{retal00a}, hereafter R00). In particular, the primary observational properties such as visual amplitude, period and visual magnitude and the contribution…
Chandra Observations of ``The Antennae'' Galaxies (NGC 4038/9)
Zezas, A.; Fabbiano, G.; Murray, S. S.
We report the results of a deep Chandra ACIS pointing at the merging system NGC 4038/9. We detect an extraordinarily luminous population of X-ray sources, with luminosity well above that of XRBs in M31 and the Milky Way. If these sources are unbeamed XRBs, our observations may point to them being 10-(a few)100 Msolar black hole counterp…
Population Gradients in Local Group Dwarf Spheroidal Galaxies
Grebel, Eva K.; Dolphin, Andrew; Holtzman, Jon +7 more
We present a systematic and homogeneous analysis of population gradients for the Local Group dwarf spheroidal galaxies (dSph's) Carina, Sculptor, Sextans, Tucana, and Andromeda I-III, V, and VI. For all of the Milky Way companions studied here, we find significant population gradients. The same is true for the remote dSph Tucana located at the out…
Investigation of Mass Flows beneath a Sunspot by Time-Distance Helioseismology
Zhao, Junwei; Kosovichev, Alexander G.; Duvall, Thomas L., Jr.
A time-distance helioseismic technique is employed to analyze a set of high-resolution Dopplergram observations of a large sunspot by SOHO/MDI on 1998 June 18. A regularized, damped least-squares inversion is applied to the measurements of travel times to infer mass flows around the sunspot below the solar surface. Powerful converging and downward…
XMM-Newton observations of the cluster of galaxies Sérsic 159-03
Kaastra, J. S.; Ferrigno, C.; Tamura, T. +3 more
The cluster of galaxies Sérsic 159-03 was observed with the XMM-Newton X-ray observatory as part of the Guaranteed Time program. X-ray spectra taken with the EPIC and RGS instruments show no evidence for the strong cooling flow derived from previous X-ray observations. There is a significant lack of cool gas below 1.5 keV as compared to standard i…
Nuclear Luminosities and Radio Loudness of Seyfert Nuclei
Ho, Luis C.; Peng, Chien Y.
Historically, Seyfert nuclei have been considered to be radio-quiet active galactic nuclei (AGNs). We question this widely held assumption by showing that the distribution of the radio-to-optical luminosity ratio, R≡Lν(6 cm)/Lν(B), when properly measured for the nuclear component, places the majority of type 1 Seyfert nuclei …
Ice absorption features in the 5-8 µm region toward embedded protostars
Whittet, D. C. B.; Schutte, W. A.; Tielens, A. G. G. M. +2 more
We have obtained 5-8 µm spectra towards 10~embedded protostars using the Short Wavelength Spectrometer on board the Infrared Space Observatory (ISO-SWS) with the aim of studying the composition of interstellar ices. The spectra are dominated by absorption bands at 6.0 µm and 6.85 µm. The observed peak positions, widths and relati…
A long-wavelength view on galaxy evolution from deep surveys by the Infrared Space Observatory
Aussel, H.; Elbaz, D.; Franceschini, A. +2 more
We discuss the constraints set on galaxy evolution by a variety of data from deep extragalactic surveys performed in the mid-IR and far-IR with the Infrared Space Observatory and with millimetric telescopes at longer wavelengths. These observations indicate extremely high rates of evolution for IR galaxies, exceeding those measured for galaxies at…