Search Publications
Missions
Journals
Publication Years
The Lensed Arc Production Efficiency of Galaxy Clusters: A Comparison of Matched Observed and Simulated Samples
Maoz, Dan; Rix, Hans-Walter; Bartelmann, Matthias +3 more
We compare the statistical properties of giant gravitationally lensed arcs produced in matched simulated and observed cluster samples. The observed sample consists of 10 X-ray-selected clusters at redshifts zc~0.2 imaged with HST by Smith et al. The simulated data set is produced by lensing the Hubble Deep Field, which serves as a backg…
Boron Depletion in F and G Dwarf Stars and the Beryllium-Boron Correlation
Deliyannis, Constantine P.; Steinhauer, Aaron; Boesgaard, Ann Merchant
Boron provides a special probe below the stellar surface since it survives to greater depths than do Li and Be. To search for B depletions we have observed B in 13 F and G dwarfs with large Be depletions; for comparison we have also obtained spectra of five stars that are undepleted in Li and Be. We have used HST with STIS to obtain spectra of the…
Diverse albedos of small trans-neptunian objects
Grundy, W. M.; Noll, K. S.; Stephens, D. C.
Discovery of trans-neptunian object (TNO) satellites and determination of their orbits has recently enabled estimation of the size and albedo of several small TNOs, extending the size range of objects having known size and albedo down into the sub-100 km range. In this paper we compute albedo and size estimates or limits for 20 TNOs, using a consi…
Supermassive black hole mass measurements for NGC 1300 and 2748 based on Hubble Space Telescope emission-line gas kinematics
Marconi, A.; Capetti, A.; Carollo, C. M. +18 more
We present Space Telescope Imaging Spectrograph emission-line spectra of the central regions of the spiral galaxies NGC 1300 and 2748. From the derived kinematics of the nuclear gas we have found evidence for central supermassive black holes in both galaxies. The estimated masses of the black holes in NGC 1300 and 2748 are (6.6+6.3…
The new ESA meteoroid model
Dikarev, V.; Grün, E.; Landgraf, M. +3 more
The orbital distributions of meteoroids in interplanetary space are revised in the ESA meteoroid model to account for recently obtained observational data and to comply with the constraints due to the orbital evolution under planetary gravity and Poynting-Robertson effects. Infrared observations of the zodiacal cloud by the COBE DIRBE instrument, …
A new reduction of the raw Hipparcos data
van Leeuwen, F.; Fantino, E.
We present an outline of a new reduction of the Hipparcos astrometric data, the justifications of which are described in the accompanying paper. The emphasis is on those aspects of the data analysis that are fundamentally different from the ones used for the catalogue published in 1997. The new reduction uses a dynamical modelling of the satellite…
Active Galactic Nucleus Feedback and Gas Mixing in the Core of NGC 4636
O'Sullivan, E.; Vrtilek, J. M.; Kempner, J. C.
Chandra observations of NGC 4636 show disturbances in the galaxy X-ray halo, including armlike high surface brightness features (tentatively identified as active galactic nucleus-driven shocks) and a possible cavity on the west side of the galaxy core. We present Chandra and XMM-Newton spectral maps of NGC 4636 that confirm the presence of the cav…
Atomic and Molecular Gas in Colliding Galaxy Systems. I. The Data
Yun, Min S.; Iono, Daisuke; Ho, Paul T. P.
We present H I and CO (1-0) interferometric observations of 10 comparable-mass interacting systems obtained at the Very Large Array (VLA) and the Owens Valley Radio Observatory (OVRO) millimeter array. The primary intent of this study is to investigate the response of cold gas during the early stages of collision of massive disk galaxies. The samp…
Opening the Treasure Chest: A Newborn Star Cluster Emerges from Its Dust Pillar in Carina
Smith, Nathan; Stassun, Keivan G.; Bally, John
We present detailed observations of the Treasure Chest, a compact nebula at the head of a dust pillar in the southern Carina Nebula. This object is of interest because it is an example of a dense young cluster containing at least one massive star, the formation of which may have been triggered by feedback from the very massive stars in the Carina …
The low X-ray state of LS 5039 / RX J1826.2-1450
Motch, C.; Negueruela, I.; Martocchia, A.
Recent XMM-Newton and Chandra observations of the high mass X-ray binary LS 5039 / RX J1826.2-1450 caught the source in a faint X-ray state. In contrast with previous RXTE observations, we fail to detect any evidence of iron line emission. We also fail to detect X-ray pulsations. The X-ray spectrum can be well fitted by a simple powerlaw, slightly…