Search Publications
Missions
Journals
Publication Years
Collisions among Clouds inside Dusty Tori in Active Galactic Nuclei:Observational Consequences
Wang, Jian-Min
A geometrically thick dusty torus in NGC 1068 has been unambiguously resolved by an infrared interferometry telescope. This implies that clouds composing the dusty torus are undergoing supersonic collisions with each other. We show that the collisions form strong nonrelativistic shocks, which accelerate populations of relativistic electrons. The t…
HST/STIS observations of sdBV stars: testing diffusion and pulsation theory
Heber, U.; Chayer, P.; Fontaine, G. +3 more
We present the initial results of an abundance analysis of echelle UV spectra of five hot subdwarf B (sdB) stars. These stars have been identified as core helium burning objects on the extreme Horizontal Branch. Around 5% of sdBs show short-period acoustic-mode oscillations. Models predict that these oscillations are due to an opacity bump caused …
60 Milliarcsecond Near-Infrared Imaging of 3C 273 with Altair and Gemini
Hutchings, J. B.; Rigaut, F.; Veran, J. -P. +1 more
We report data from the commissioning run of the Altair adaptive optics instrument on Gemini North. The bright QSO 3C 273 was observed at f/32 in the H and J bands, and at f/14 with J band, using the QSO itself as guide star. Resolution of approximately 60 mas full width at half-maximum (FWHM) was achieved in H band. The data and point-spread func…
Mid-Infrared Observations of van Maanen 2: No Substellar Companion
Becklin, E. E.; Farihi, J.; Macintosh, B. A.
The results of a comprehensive infrared imaging search for the putative 0.06 Msolar astrometric companion to the 4.4 pc white dwarf van Mannen 2 are reported. Adaptive optics images acquired at 3.8 µm reveal a diffraction-limited core of 0.09" and no direct evidence of a secondary. Models predict that at 5 Gyr, a 50MJ b…
The Stellar Populations of dE Galaxies in Nearby Groups
Da Costa, G. S.
In this contribution Gemini-North NIRI J,K-observations are used to investigate the upper-Asymptotic Giant Branch (AGB) intermediate-age population in the M81 Group dwarf elliptical (dE) F8D1. Hubble Space Telescope (HST) `snapshot' V,I-observations are also analysed to investigate the upper-AGB populations in two other M81 Group dEs, DDO 71 and k…
The Cassini-Huygens flyby of Jupiter
Lebreton, Jean-Pierre; Matson, Dennis L.; Spilker, Linda J. +2 more
The Cassini-Huygens spacecraft flew by Jupiter on December 30, 2000. The instruments aboard the spacecraft started making scientific observations three months earlier. Joint, collaborative observations were carried out with the teams of other spacecraft, notably Galileo, and with Earth-based observers. An operational overview of the flyby is prese…
Local kinematics of dwarfs from the Tycho-2 data
Rybka, S. P.
The stellar velocity field of about 70000 dwarfs within 2 kps from the Sun is investigated from the "Tycho-2" data and known MK spectral classification. The Ogorodnikov-Milne model of a three-dimensional differential velocity field is used. The generalized Oort constants and components of the solar motion with respect to various spectral groups ar…
XMM-Newton observations of the BL Lac MS 0205.7+3509: A dense, low-metallicity absorber
Hanlon, L.; McBreen, B.; Smith, N. +5 more
The high-frequency-peaked BL Lac, MS 0205.7+3509 was observed twice with XMM-Newton. Both X-ray spectra are synchrotron-dominated, with mean 0.2-10 keV fluxes of 2.80±0.01 and 3.34±0.02×10-12 erg cm-2 s-1. The X-ray spectra are well fit by a power-law with absorption above the Galactic value, however no absorption …
Comprehensive Analysis of RGU Photometry in the Direction to M5
Bilir, S.; Karaali, S.; Buser, R.
The RGU-photographic investigation of an intermediate latitude field in the direction to the Galactic centre is presented. 164 extra-galactic objects, identified by comparison of Minnesota and Basel charts, are excluded from the program. Also, a region with size 0.104 square-degrees, contaminated by cluster (M5) stars and affected by background li…
Extended search for correlation between solar mean magnetic field BiSON data and coronal mass ejections
Chaplin, William J.; Pintér, Balázs; Elsworth, Yvonne P. +5 more
The Birmingham Solar-Oscillations Network (BiSON) has acquired high-precision solar mean magnetic field (SMMF) data on a 40-s cadence for a decade. We present attempts to compare such data from recent years with the occurrence of coronal mass ejections (CMEs) as recorded by LASCO, using correlation techniques applied to measurements from different…