Search Publications
The Moth: An Unusual Circumstellar Structure Associated with HD 61005
Henning, Thomas; Schneider, Glenn; Hines, Dean C. +11 more
We present the discovery of an unusual spatially resolved circumstellar structure associated with the ~90 Myr, nearby, G dwarf star HD 61005. Observations from the FEPS Spitzer Legacy Science survey reveal thermal emission in excess of expected stellar photospheric levels. Follow-up 0.1" resolution HST NICMOS coronagraphic images reveal scattered …
Evolution of magnetic fields in stars across the upper main sequence: II. Observed distribution of the magnetic field geometry
Hubrig, S.; North, P.; Schöller, M.
We re-discuss the evolutionary state of upper main sequence magnetic stars using a sample of Ap and Bp stars with accurate Hipparcos parallaxes and definitely determined longitudinal magnetic fields. We confirm our previous results obtained from the study of Ap and Bp stars with accurate measurements of the mean magnetic field modulus and mean qua…
Multi-spacecraft observation of plasma dipolarization/injection in the inner magnetosphere
Sauvaud, J. -A.; Daly, P. W.; Khotyaintsev, Y. +13 more
Addressing the origin of the energetic particle injections into the inner magnetosphere, we investigate the 23 February 2004 substorm using a favorable constellation of four Cluster (near perigee), LANL and Geotail spacecraft. Both an energy-dispersed and a dispersionless injection were observed by Cluster crossing the plasma sheet horn, which map…
Mass Selection and the Evolution of the Morphology-Density Relation from z = 0.8 to 0
Kelson, D. D.; Demarco, R.; Rosati, P. +11 more
We examined the morphology-density relations for galaxy samples selected by luminosity and by mass in each of five massive X-ray clusters from z=0.023 to 0.83 for 674 spectroscopically confirmed members. Rest-frame optical colors and visual morphologies were obtained primarily from Hubble Space Telescope images. The visual morphologies ensure cons…
Proper Motions of the Jets in the Region of HH 30 and HL/XZ Tau: Evidence for a Binary Exciting Source of the HH 30 Jet
Anglada, Guillem; Masegosa, Josefa; Estalella, Robert +3 more
We present [S II] images of the HH 30 and HL/XZ Tau region obtained at two epochs, as well as long-slit optical spectroscopy of the HH 30 jet. We measured proper motions of ~100-300 km s-1 for the HH 30 jet and counterjet and of ~120 km s-1 for the HL Tau jet. Inclination angles with respect to the plane of the sky are 0°-40°…
Suzaku Discovery of Iron Absorption Lines in Outburst Spectra of the X-Ray Transient 4U 1630-472
Done, Chris; Dotani, Tadayasu; Fabian, Andrew C. +12 more
We present the results of six Suzaku observations of the recurrent black hole transient 4U 1630-472 during its decline from outburst from February 8 to March 23 in 2006. All observations show the typical high/soft state spectral shape in the 2-50keV band, roughly described by an optically thick-disk spectrum in the soft energy band plus a weak pow…
Direct constraint on the distance of γ2 Velorum from AMBER/VLTI observations
Beckmann, U.; Marconi, A.; Testi, L. +99 more
Context: Interferometry can provide spatially resolved observations of massive star binary systems and their colliding winds, which thus far have been studied mostly with spatially unresolved observations.
Aims: We present the first AMBER/VLTI observations, taken at orbital phase 0.32, of the Wolf-Rayet and O (WR+O) star binary system
The Disk and Environment of a Young Vega Analog: HD 169142
Ménard, F.; Quirrenbach, A.; Hamaguchi, K. +15 more
We trace the disk of HD 169142 (A8 Ve) from 0.57" to 1.4" (~80-200 AU projected distance) in 1.1 µm scattered light with HST NICMOS coronagraphy. The azimuthally symmetric disk has a peak azimuthally medianed surface brightness (SB) of ~5 mJy arcsec-2 at 0.57" from the star, and drops ~r-3. This radial SB profile is con…
Using Weak-Lensing Dilution to Improve Measurements of the Luminous and Dark Matter in A1689
Broadhurst, Tom; Kong, Xu; Coe, Dan +6 more
The E/S0 sequence of a cluster defines a boundary redward of which a reliable weak-lensing signal can be obtained from background galaxies, uncontaminated by cluster members. For bluer colors, both background and cluster members are present, reducing the average distortion signal by the proportion of unlensed cluster members. In deep Subaru and HS…
Spectacular Shells in the Host Galaxy of the QSO MC2 1635+119
Schweizer, François; Lacy, Mark; Stockton, Alan +4 more
We present deep HST ACS images and Keck spectroscopy of MC2 1635+119, a QSO hosted by a galaxy previously classified as an undisturbed elliptical galaxy. Our new images reveal dramatic shell structure indicative of a merger event in the relatively recent past. The brightest shells in the central regions of the host are distributed alternately in r…