Search Publications
Missions
Journals
Publication Years
On the Metallicity Dependence of the 24 µm Luminosity as a Star Formation Tracer
Battaner, E.; Relaño, M.; Vílchez, J. M. +2 more
We investigate the use of the rest-frame 24 µm luminosity as an indicator of the star formation rate (SFR) in galaxies with different metallicities by comparing it to the (extinction-corrected) Hα luminosity. We carry out this analysis in two steps: First, we compare the emission from H II regions in different galaxies with metallicities bet…
X-ray emission from the stellar population in M 32
Revnivtsev, M.; Sazonov, S.; Churazov, E. +2 more
Using Chandra observations, we study the X-ray emission of the stellar population in the compact dwarf elliptical galaxy M 32. The proximity of M 32 allows one to resolve all bright point sources with luminosities higher than 8×1033~erg~s-1 in the 0.5-7 keV band. The remaining (unresolved) emission closely follows the galaxy'…
Anisotropy in the Hubble constant as observed in the HST extragalactic distance scale key project results
McClure, M. L.; Dyer, C. C.
Based on general relativity, it can be argued that deviations from a uniform Hubble flow should be thought of as variations in the Universe's expansion velocity field, rather than being thought of as peculiar velocities with respect to a uniformly expanding space. The aim of this paper is to use the observed motions of galaxies to map out variatio…
The molecular and dusty composition of Betelgeuse's inner circumstellar environment
Nguyen, Q. N.; Lopez, B.; Leinert, Ch. +6 more
Context: The study of the atmosphere of red supergiant stars in general and of
Aims: A molecular shell, the MOLsphere (Tsuji 2000a, ApJ, 538, 80…
Observations of O I and Ca II Emission Lines in Quasars: Implications for the Site of Fe II Line Emission
Kawara, K.; Oyabu, S.; Tsuzuki, Y. +1 more
We present results of the near-infrared (IR) spectroscopy of six quasars whose redshifts range from 0.158 to 1.084. Combined with the satellite ultraviolet data, the relative line strengths of O I λ1304, O I λ8446, O I λ11287, and the near-IR Ca II triplet are given. In addition, the corresponding O I line strengths measured in normal Seyfert 1s a…
Titan's corona: The contribution of exothermic chemistry
Johnson, R. E.; Waite, J. H.; Cravens, T. E. +4 more
The contribution of exothermic ion and neutral chemistry to Titan's corona is studied. The production rates for fast neutrals N 2, CH 4, H, H 2, 3CH 2, CH 3, C 2H 4, C 2H 5, C 2H 6, N( 4S), NH, and HCN are …
How Does Large Flaring Activity from the Same Active Region Produce Oppositely Directed Magnetic Clouds?
Harra, Louise K.; Wang, Jingxiu; van Driel-Gesztelyi, Lidia +7 more
We describe the interplanetary coronal mass ejections (ICMEs) that occurred as a result of a series of solar flares and eruptions from 4 to 8 November 2004. Two ICMEs/magnetic clouds occurring from these events had opposite magnetic orientations. This was despite the fact that the major flares related to these events occurred within the same activ…
Discoveries of Diffuse Iron Line Sources from the Sgr B Region
Maeda, Yoshitomo; Koyama, Katsuji; Matsumoto, Hironori +8 more
The radio complex Sgr B region was observed with the X-ray Imaging Spectrometer (XIS) on board Suzaku. This region exhibits diffuse iron lines at 6.4, 6.7, and 6.9keV, which are Kα lines of Fe I (neutral iron), Fe XXV (He-like iron), and Fe XXVI (H-like iron), respectively. The high energy resolving power of the XIS provided separate maps of the K…
Remnant of a ``Wet'' Merger: NGC 34 and Its Young Massive Clusters, Young Stellar Disk, and Strong Gaseous Outflow
Seitzer, Patrick; Schweizer, François
This paper presents new images and spectroscopic observations of NGC 34 (Mrk 938) obtained with the du Pont 2.5 m and Baade 6.5 m telescopes at Las Campanas, plus photometry of an archival V image obtained with Hubble Space Telescope. This MV=-21.6 galaxy has often been classified as a Seyfert 2, yet recently published infrared spectra …
The spatial morphology of Europa's near-surface O 2 atmosphere
Johnson, R. E.; Cooper, J. F.; McGrath, M. A. +2 more
Results from a three-dimensional ballistic model of Europa's O 2 atmosphere are presented. Hubble Space Telescope (HST) ultraviolet observations show spatially non-uniform O 2 airglow from Europa. One explanation for this is that the O 2 atmosphere is spatially non-uniform. We show that non-uniform ejection of O