5 research outputs found
X-ray Observations of the Warm-Hot Intergalactic Medium
We present Chandra observations that provide the most direct evidence to date
for the pervasive, moderate density, shock-heated intergalactic medium
predicted by leading cosmological scenarios. We also comment briefly on future
observations with Constellation-X.Comment: To be published in the proceedings of the conference "IGM/Galaxy
Connection- The Distribution of Baryons at z=0". 6 page
The new very small angle neutron scattering spectrometer at Laboratoire Leon Brillouin
The design and characteristics of the new very small angle neutron scattering
spectrometer under construction at the Laboratoire Leon Brillouin is described.
Its goal is to extend the range of scattering vectors magnitudes towards
2x10{-4} /A. The unique feature of this new spectrometer is a high resolution
two dimensional image plate detector sensitive to neutrons. The wavelength
selection is achieved by a double reflection supermirror monochromator and the
collimator uses a novel multibeam design
The luminosity function of field galaxies
Schmidt's method for construction of luminosity function of galaxies is
generalized by taking into account the dependence of density of galaxies from
the distance in the near Universe. The logarithmical luminosity function (LLF)
of field galaxies depending on morphological type is constructed. We show that
the LLF for all galaxies, and also separately for elliptical and lenticular
galaxies can be presented by Schechter function in narrow area of absolute
magnitudes. The LLF of spiral galaxies was presented by Schechter function for
enough wide area of absolute magnitudes: . Spiral galaxies differ slightly by
parameter . At transition from early spirals to the late spirals parameter in
Schechter function is reduced. The reduction of mean luminosity of galaxies is
observed at transition from elliptical galaxies to lenticular galaxies, to
early spiral galaxies, and further, to late spiral galaxies, in a bright end, .
The completeness and the average density of samples of galaxies of different
morphological types are estimated. In the range the mean number density of all
galaxies is equal 0.127 Mpc-3.Comment: 14 page, 8 figures, to appear in Astrophysic
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Probing O VI Emission in the Halos of Edge-on Spiral Galaxies
We have used the Far Ultraviolet Spectroscopic Explorer to search for O VI λλ1031.926, 1037.617 emission in the halos of the edge-on spiral galaxies NGC 4631 and NGC 891. In NGC 4631, we detected O VI in emission toward a soft X-ray bubble above a region containing numerous Hα arcs and filaments. The line-of-sight component of the motion of the O VI gas appears to match the underlying disk rotation. The observed O VI luminosities can account for 0.2%-2% of the total energy input from supernovae (assuming a full O VI- emitting halo) and yield mass flux cooling rates between 0.48 and 2.8 M yr-1 depending on the model used in the derivations. On the basis of these findings, we believe it is likely that we are seeing cooling, galactic fountain gas. No emission was detected from the halo of NGC 891, a galaxy in a direction with considerably high foreground Galactic extinction