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Thick disks and halos of spiral galaxies M 81, NGC 55 and NGC 300
Tikhonov, N. A.; Galazutdinova, O. A.; Drozdovsky, I. O.
By using images from the HST/WFPC2/ACS archive, we have analyzed the spatial distribution of the AGB and RGB stars along the galactocentric radius of nearby spiral galaxies M 81, NGC 300 and NGC 55. Examining color-magnitude diagrams and stellar luminosity functions, we gauge the stellar contents of the surroundings of the three galaxies. The red …
Integral field spectroscopy of the ultraluminous X-ray source Holmberg II X-1
Greiner, J.; Costantini, E.; Roth, M. +10 more
We present optical integral field observations of the H II region containing the ultraluminous X-ray source Holmberg II X-1. We confirm the existence of an X-ray ionized nebula as the counterpart of the source owing to the detection of an extended He II λ4686 region (21× 47 pc) at the Chandra ACIS-S position. An extended blue object with a size of…
On the possibility of measuring the solar oblateness and some relativistic effects from planetary ranging
Iorio, L.
In this paper we first calculate the post-Newtonian gravitoelectric secular rate of the mean anomaly of a test particle freely orbiting a spherically symmetric central mass. Then, we propose a novel approach to suitably combine the presently available planetary ranging data to Mercury, Venus and Mars in order to determine, simultaneously and indep…
Molecular gas in a z ∼ 2.5 triply-imaged, sub-mJy submillimetre galaxy typical of the cosmic far-infrared background
Smail, I.; Kneib, J. -P.; van der Werf, P. +4 more
We present the results of observations from the Plateau de Bure IRAM interferometric array of the submillimetre (submm) galaxy SMMJ16359+6612 lying at z=2.516 behind the core of the massive cluster A 2218. The foreground gravitational lens produces three images with a total magnification of 45 of this faint submm galaxy, which has an intrinsic sub…
X-ray spectra of XMM-Newton serendipitous medium flux sources
Page, M. J.; Barcons, X.; Carrera, F. J. +7 more
We report on the results of a detailed analysis of the X-ray spectral properties of a large sample of sources detected serendipitously with the XMM-Newton observatory in 25 selected fields, for which optical identification is in progress. The survey covers a total solid angle of ~3.5 deg2 and contains 1137 sources with ~10-15…
Abundances and chemical stratification analysis in the atmosphere of Cr-type Ap star HD 204411
Ryabchikova, T.; Leone, F.; Kochukhov, O.
We present results of an abundance and stratification analysis of the weakly magnetic chemically peculiar star HD 204411 based on the echelle spectrum obtained with the high resolution spectrograph at the 3.55-m Telescopio Nazionale Galileo at the Observatorio del Roque de los Muchachos (La Palma, Spain). Atmospheric parameters obtained from the s…
The 1st INTEGRAL SPI-ACS gamma-ray burst catalogue
Hurley, K.; Rau, A.; Lichti, G. G. +1 more
We present the sample of gamma-ray bursts detected with the anti-coincidence shield ACS of the spectrometer SPI on-board INTEGRAL for the first 26.5 months of mission operation (up to Jan. 2005). SPI-ACS works as a nearly omnidirectional gamma-ray burst detector above ~80 keV but lacks spatial and spectral information. In this catalogue, the prope…
Absorption and scattering by interstellar dust: an XMM-Newton observation of Cyg X-2
Costantini, E.; Freyberg, M. J.; Predehl, P.
We present results of the XMM-Newton observation of the bright X-ray binary Cyg X-2. In our analysis we focus on the absorption and scattering of the X-ray emission by interstellar dust distributed along the line of sight. The scattering halo around Cyg X-2, observed with the CCD detector EPIC-pn, is well detected up to 7 arcmin and contributes 5-…
The mass of the black hole in 3C 273
Paltani, S.; Türler, M.
In this paper we apply the reverberation method to determine the mass of the black hole in 3C 273 from the Lyα and Civ emission lines using archival IUE observations. Following the standard assumptions of the method, we find a maximum-likelihood estimate of the mass of 6.59× 10^9 M_⊙, with a 1σ confidence interval 5.69{-}8.27× 109 M_⊙. …
HST/ACS observations of the old and metal-poor Sagittarius dwarf irregular galaxy
Gullieuszik, M.; Momany, Y.; Clemens, M. +6 more
We have obtained deep color-magnitude diagrams (CMDs) of the Sagittarius dwarf irregular galaxy with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope. The new diagrams show for the first time the star formation history of SagDIG. The young main-sequence is traced down to mF606W ≃27.5, well separated from the old…