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X-ray emission of young SN Ia remnants as a probe for an explosion model
Lundqvist, P.; Sorokina, E. I.; Blinnikov, S. I. +1 more
We present results of hydrodynamical simulations of young supernova remnants. To model the ejecta, we use several models (discussed in the literature) of type Ia supernova explosions with different abundances. Our hydro models are one-dimensional and spherically symmetrical, but they take into account ionization kinetics with all important process…
Solar Neighbourhood Age-Metallicity Relation Based on Hipparcos Data
Ibukiyama, Akihiko
We derive age-metallicity relations (AMRs) and orbits for the 1658 solar neighbourhood stars for which accurate distances are measured by the Hipparcos satellite. The sample comprises 1382 thin disk stars, 229 thick disk stars, and 47 halo stars according to their orbital parameters. We find a considerable scatter for thin disk AMRs along the one-…
The first XMM-Newton study of two Narrow-Line Seyfert 1 galaxies discovered in the Sloan Digital Sky Survey
Ponti, G.; Grandi, P.; Foschini, L. +6 more
The Early Data Release of the Sloan Digital Sky Survey (SDSS) contains 150 Narrow-Line Seyfert 1 (NLS1) galaxies, most of them previously unknown. We present here the study of the X-ray emission from two of these active galaxies (SDSS J030639.57+000343.2 and SDSS J141519.50-003021.6), based upon XMM-Newton observations. The spectral and timing cha…
A new mass-ratio for the X-ray binary X2127+119 in M 15?
Charles, P. A.; Naylor, T.; Ioannou, Z. +1 more
The luminous low-mass X-ray binary X2127+119 in the core of the globular cluster M 15 (NGC 7078), which has an orbital period of 17 hours, has long been assumed to contain a donor star evolving off the main sequence, with a mass of 0.8 M⊙space (the main-sequence turn-off mass for M 15). We present orbital-phase-resolved spectroscopy of …
Direct imaging of Titan's extended haze layer from HST observations
Young, E. F.; Puetter, R.; Yahil, A.
In the early 1980s, both Voyager spacecraft imaged a detached haze layer surrounding Titan, separated from the main haze distribution by a gap at around ~300 km and merging into a hood of more concentrated haze at Titan's north pole. We have processed Hubble Space Telescope images of Titan with Lucy-Richardson and PIXON deconvolution software and …
X-ray broad line emission in Seyfert galaxies: Mrk 766 and NGC 4051
Page, M. J.; Branduardi-Raymont, G.; Mason, K. O. +3 more
Long (>100 ks) observations of the bright Seyfert galaxies Mrk 766 and NGC 4051 have been obtained using XMM- Newton. The RGS 5-38 Å spectra reveal evidence of broad features. These can be modelled with relativistic emission lines coming from the immediate vicinity of a massive rotating black hole. Lines of OVIII, NVII and CVI are required to r…
Observations of CME-related phenomena in a wide spectral range
Grechnev, V. V.; Uralov, A. M.; Borovik, V. N. +7 more
We study pre-eruptive, eruptive, and post-eruptive phenomena related to a CME that occurred on November 23, 2000 by means of joint analyses of data from various spectral ranges. Almost all known CME-associated phenomena were observed during this event, i.e., a filament eruption, solar flare, dimmings, and a post-eruptive arcade formation. Followin…
Huygens/HASI 2002 balloon test campaign: Probe trajectory and atmospheric vertical profiles reconstruction
Fulchignoni, M.; Colombatti, G.; Ferri, F. +2 more
In the framework of the activities going on in preparation for the mission of the Huygens probe in Titan's atmosphere (January 2005), the Huygens Atmospheric Structure Instrument (HASI) team scheduled and performed several balloon campaigns to test the HASI sensors' performance in flight conditions in the Earth's atmosphere. In particular, pressur…
Analysis of UBV photometry in selected area 133
Karataş, Y.; Bilir, S.; Karaali, S. +1 more
We interpret the de-reddened UBV data for the field SA 133 to deduce the stellar density and metallicity distribution functions. The logarithmic local space density for giants, D*(0)=6.40, and the agreement of the luminosity function for dwarfs and sub-giants with the one of Hipparcos confirms the empirical method used for their separat…
Properties of the isolated neutron star RX J185635-3754
Burwitz, V.; Neuhäuser, R.; Pons, J. A. +5 more
Despite improved observational capabilities, the surface properties of neutron stars remain uncertain. In principle, multiwavelength spectra can reveal their compositions and angular diameters and constrain the interior equation of state. The Chandra LETG spectrum of the brightest isolated neutron star is a featureless continuum. The X-ray blackbo…