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An ISOCAM survey through gravitationally lensing galaxy clusters. III. New results from mid-infrared observations of the cluster Abell 2219
Smail, I.; Kneib, J. -P.; Altieri, B. +7 more
The massive cluster of galaxies Abell 2219 (z = 0.228) with two spectacular gravitational lensing arcs was observed at 14.3 µm (hereafter 15 µm) with the Infrared Space Observatory and results were published by Barvainis et al. (\cite{1999AJ....118..645B}). These observations have been reanalyzed using a method specifically designed fo…
Discovery of a bright X-ray transient in the Galactic Center with XMM-Newton
Burwitz, V.; Grosso, N.; Warwick, R. S. +4 more
We report the discovery of a bright X-ray transient object,
Discovery of a Solitary Dwarf Galaxy in the APPLES Survey
Pirzkal, Norbert; Walsh, Jeremy R.; Malhotra, Sangeeta +5 more
During the APPLES parallel campaign, the Hubble Space Telescope (HST) Advanced Camera for Surveys has resolved a distant stellar system, which appears to be an isolated dwarf galaxy. It is characterized by a circularly symmetric distribution of stars with an integrated magnitude mF775W=20.13+/-0.02, a central surface brightness µ<…
Kinematics of RHB stars to trace the structure of the Galaxy
de Boer, K. S.; Altmann, M.; Kaempf, T. A.
Red horizontal-branch (RHB) stars have been selected from the Hipparcos catalogue to investigate their kinematics and spatial distribution. Hipparcos parallaxes, literature radial velocities and Hipparcos proper motions, together with models for the gravitational potential of the Milky Way allow a calculation of the actual velocity vectors and the…
Kinematic and chemical evolution of early-type galaxies
Böhm, A.; Thomas, D.; Bender, R. +3 more
We investigate in detail 13 early-type field galaxies with 0.2<z<0.7 drawn from the Fors Deep Field. Since the majority (9 galaxies) is at z≈0.4, we compare the field galaxies to 22 members of three rich clusters with z=0.37 to explore possible variations caused by environmental effects. We exploit VLT/FORS spectra (R≈1200) and HST/ACS imagi…
The ionization structure of early-B supergiant winds
Massa, D.; Prinja, R. K.; Searle, S. C.
We present empirically determined ionization conditions for the winds of 106 luminous B0 to B5 stars observed by IUE. The UV wind lines are modelled to extract products of mass-loss rates times ionization fractions (\mdot qi(w) where w = v/v∞) for N V, C IV, Si IV, Si III, Al III and C II. We describe the general behaviour of…
In Search of the Solar Cycle Variations of p-Mode Frequencies Generated by Perturbations in the Solar Interior
Chou, Dean-Yi; Serebryanskiy, Alexander
Observations show that the solar p-mode frequencies change with the solar cycle. The horizontal phase velocity dependence of the relative frequency change, scaled by mode mass, provides depth information on the perturbation in the solar interior. Our model study suggests that variations of smoothed, scaled relative frequency change versus horizont…
Keck HIRES Spectroscopy of Four Candidate Solar Twins
King, Jeremy R.; Boesgaard, Ann M.; Schuler, Simon C.
We use high signal-to-noise ratio, high-resolution Keck HIRES spectroscopy of four solar twin candidates (HIP 71813, 76114, 77718, and 78399) pulled from our Hipparcos-based Ca II H and K survey to carry out parameter and abundance analyses of these objects. Our spectroscopic Teff estimates are ~100 K hotter than the photometric scale of the recen…
O/H in the Local Bubble
Chayer, Pierre; Dupuis, Jean; Oliveira, Cristina M. +1 more
We present new measurements of the oxygen gas-phase abundance along four sight lines probing gas inside the Local Bubble, using data obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Hubble Space Telescope (HST). Combining these with seven previously published N(O I) and N(H I) measurements, we determine a mean O/H ratio for …
Titan interaction with Saturn's magnetosphere: Voyager 1 results revisited
Johnson, R. E.; Hartle, R. E.; Sittler, E. C. +3 more
We investigate the details of Titan's interaction with Saturn's magnetosphere, which includes formation and location of an ionopause, mass loading via ion pickup, and the effects of finite gyroradii. We present new interpretations of the Voyager 1 plasma instrument measurements not addressed by Hartle et al. (1982). Pickup ions H+ and H…