Search Publications
Can the unresolved X-ray background be explained by the emission from the optically-detected faint galaxies of the GOODS project?
Lehmer, B. D.; Alexander, D. M.; Bauer, F. E. +3 more
The emission from individual X-ray sources in the Chandra Deep Fields and XMM-Newton Lockman Hole shows that almost half of the hard X-ray background above 6keV is unresolved and implies the existence of a missing population of heavily obscured active galactic nuclei (AGN). We have stacked the 0.5-8keV X-ray emission from optical sources in the Gr…
Observations of Flux Rope Formation in the Outer Corona
Sheeley, N. R., Jr.; Wang, Y. -M.
In previous studies employing the Large Angle and Spectrometric Coronagraph (LASCO), we identified a class of white-light ejections that separate into incoming and outgoing components at distances of ~3-5 Rsolar from Sun center. These events, of which up to several per month are observed during high solar activity, are generally precede…
Exploring the lower mass function in the young open cluster IC 4665
James, D. J.; Testi, L.; Palla, F. +8 more
We present a study of the young (30-100 Myr) open cluster IC 4665 with the aim to determine the shape of the mass function well into the brown dwarf regime. We photometrically select 691 low-mass stellar and 94 brown dwarf candidate members over an area of 3.82 square degrees centred on the cluster. K-band follow-up photometry and Two-Micron All-S…
INTEGRAL and RXTE monitoring of GRS 1758-258 in 2003 and 2004. A transition from the dim soft state to the hard state
Pottschmidt, K.; Zdziarski, A. A.; Lubiński, P. +3 more
The Galactic Center black hole candidate (BHC)
NICMOS2 Hubble Space Telescope Observations of the Embedded Cluster Associated with Mon R2: Constraining the Substellar Initial Mass Function
Dougados, C.; Andersen, M.; Meyer, M. R. +2 more
We have analyzed Hubble Space Telescope NICMOS2 F110W-, F160W-, F165M-, and F207M-band images covering the central 1'×1' region of the cluster associated with Mon R2 in order to constrain the initial mass function (IMF) down to 20MJ. The flux ratio between the F165M and F160W bands was used to measure the strength …
Evolution of the Reverse Shock Emission from SNR 1987A
Pun, C. S. J.; Smith, Nathan; Garnavich, Peter +13 more
We present new (2004 July) G750L and G140L Space Telescope Imaging Spectrograph (STIS) data of the Hα and Lyα emission from supernova remnant (SNR) 1987A. With the aid of earlier data, from 1997 October to 2002 October, we track the local evolution of Lyα emission and both the local and global evolution of Hα emission. The most recent observations…
Tracing gas motions in the Centaurus cluster
Fabian, A. C.; Sanders, J. S.; Morris, R. G. +1 more
We apply the stochastic model of iron transport developed by Rebusco et al. to the Centaurus cluster. Using this model, we find that an effective diffusion coefficient D in the range 2 × 1028-4 × 1028cm2s-1 can approximately reproduce the observed abundance distribution. Reproducing the flat central prof…
On the vertical wind shear of Saturn's Equatorial Jet at cloud level
Sánchez-Lavega, A.; Pérez-Hoyos, S.
In this work we analyze and compare the vertical cloud structure of Saturn's Equatorial Zone in two different epochs: the first one close to the Voyagers flybys (1979-1981) and the second one in 2004, when the Cassini spacecraft entered its orbit around the planet. Our goal is to retrieve the altitude of cloud features used as zonal wind tracers i…
Far-Ultraviolet Imaging of the Hubble Deep Field-North: Star Formation in Normal Galaxies at z<1
Gardner, Jonathan P.; Dickinson, M.; Chary, R. +8 more
We present far-ultraviolet (FUV) imaging of the Hubble Deep Field-North (HDF-N) taken with the Solar Blind Channel of the Advanced Camera for Surveys (ACS SBC) and the FUV MAMA detector of the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope. The full WFPC2 deep field has been observed at 1600 Å. We detect 134 galaxies and o…
Radial velocities of 35495 Hipparcos stars in a common system
Gontcharov, G. A.
The Pulkovo Compilation of Radial Velocities (PCRV) catalogue has been produced to study stellar kinematics in the local spiral arm. The PCRV contains the mean weighted absolute radial velocities of 35495 Hipparcos stars of various spectral types and luminosity classes over the whole celestial sphere mainly within the radius of 500pc from the Sun.…