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Highlights from HST/NICMOS
Schneider, G.
The near-infrared camera and multi-object spectrometer (NICMOS) was installed in the Hubble Space Telescope in February 1997. After 22 months of operation the 110 kg supply of solid N 2, which cooled the NICMOS-3 HgCdTe detectors, was exhausted. The cryostat warmed up leaving the instrument in an electromechanically functional, but scie…
Beagle-2 position determination from the returned camera panoramas using MOLA data
Michael, G. G.
After the Beagle-2 lander of the Mars Express mission comes to rest on the surface of Isidis Planitia in late December 2003 to carry out a range of geochemistry and exobiology experiments, there will be considerable interest in determining its exact location. This work considers the feasibility of identifying topographic features seen in the Mars …
Compiled catalogue of stellar proper motions in the Hipparcos system in MEGA program areas
Kharchenko, N. V.
The compiled catalogue of proper motions in the Hipparcos system MEGA-H is created for 18169 stars. The data of the original catalogue (MEGA-G) and All-Sky Compiled Catalogue of 2.5 million stars (ASCC-2.5) are used. The errors of magnitude equation and zero-point are taken into account in each 47 program areas individually.
X-rays from the Local Bubble
Freyberg, Michael J.
Thermal plasma emission in the soft X-ray band (0.1–2.0 keV)is believed to be responsible for the bulk of the X-ray intensityseen from the Local Bubble, a low-density cavity extending over∼ 70–200 pc around the Sun. The state of the hot plasmais still a matter of discussion as previous instrumentation like aboardROSAT was not able to unambiguously…
On the precision of X-ray source parameters estimated from ROSAT data
Boese, F. G.
The precision of the point source parameters, i.e. those for source position, source counts and source extension obtained via Maximum Likelihood Estimation from ROSAT data, is investigated. The various categories of error in X-ray observatories are identified. An analytic perturbation analysis is set forth. This means in the ROSAT case a perturbat…
Light Elements for V353 Hydrae, a Hipparcos Eclipsing Binary
Stephan, C.; Otero, S. A.
The Hipparcos eclipsing binary V353 Hydrae has been observed visually in order to determine its period. Results of this campaign are presented. The system is an eclipsing binary in a circular orbit. The combination of visual, Hipparcos, and ASAS-3 data finally revealed that the period is 7.56 days.
The optical to X-ray spectrum of the broad-line ultrasoft AGN RE J2248-511
Mason, K. O.; Starling, R. L. C.; Romero-Colmenero, E. +1 more
We present a series of monitoring observations of the ultrasoft broad-line Seyfert galaxy RE J2248-511 with XMM-Newton. Previous X-ray observations showed a transition from a very soft state to a harder state five years later. We find that the ultrasoft X-ray excess has re-emerged, yet there is no change in the hard power-law. Reflection models wi…
Disentangling X-ray Reprocessing Sites in EXO 0748-676
Charles, P. A.; Horne, K.; O'Brien, K. +5 more
We present first results from a coordinated multiwavelength study of the neutron star low-mass X-ray binary EXO 0748-676. Fast UV, X-ray, and optical data were obtained including both spectral and timing information. We discuss how this study allows us to probe the temperature distribution within the binary and hence the geometry and efficiency of…
The entropy in groups a clue to galaxy formation
Mushotzky, Richard
The entropy in the hot X-ray gas in groups of galaxies is a fossil of the process of galaxy formation The amount of entropy in these low mass systems considerably exceeds that predicted from structure formation models. To explain these results requires "extra" energy which is a relic of the process of star formation and active galaxy heating. We p…
Solar wind velocity at solar maximum: A search for latitudinal effects
Bavassano, B.; Bruno, R.; D'Amicis, R.
Observations by Ulysses during its second out-of-ecliptic orbit have shown that near the solar activity maximum the solar wind appears as a highly variable flow at all heliolatitudes. In the present study Ulysses data from polar latitudes are compared to contemporary ACE data in the ecliptic plane to search for the presence of latitudinal effects …