Search Publications
Role of emission angular directionality in spin determination of accreting black holes with a broad iron line
Dovčiak, M.; Karas, V.; Svoboda, J. +1 more
Aims: The spin of an accreting black hole can be determined by spectroscopy of the emission and absorption features produced in the inner regions of an accretion disc. In this work, we discuss the method employing the relativistic line profiles of iron in the X-ray domain, where the emergent spectrum is blurred by general relativistic effects.
Mode width fitting with a simple Bayesian approach. Application to CoRoT targets HD 181420 and HD 49933
Appourchaux, T.; Boumier, P.; Gaulme, P.
Aims: We investigate the asteroseismology of two solar-like targets as observed with the CoRoT satellite, with particular attention paid to the mode fitting. HD 181420 and HD 49933 are typical CoRoT solar-like targets (156 and 60-day runs). The low signal-to-noise ratio (SNR) of about 3{-}10 prevents us from unambiguously identifying the individua…
The young stellar population at the center of NGC 205
Bellazzini, M.; Saviane, I.; Monaco, L. +5 more
Context: NGC 205 is a peculiar dwarf elliptical galaxy hosting in its center a population of young blue stars. Their origin is still matter of debate, the central fresh star formation activity possibly being related to dynamical interactions between NGC 205 and M 31.
Aims: The star formation history in the central 30´´ (~120 pc) around the NGC…
Variations in the dip properties of the low-mass X-ray binary XB 1254-690 observed with XMM-Newton and INTEGRAL
Díaz Trigo, M.; Parmar, A. N.; Boirin, L. +3 more
We have analysed data from five XMM-Newton observations of XB 1254-690, one of them simultaneous with INTEGRAL, to investigate the mechanism responsible for the highly variable dip durations and depths seen from this low-mass X-ray binary. Deep dips were present during two observations, shallow dips during one and no dips were detected during the …
Multiwavelength observations of a rich galaxy cluster at z ∼ 1. The HST/ACS colour-magnitude diagram
Böhringer, H.; Lidman, C.; Perlmutter, S. +12 more
Context: XMMU J1229+0151 is a rich galaxy cluster with redshift z=0.975 that was serendipitously detected in X-rays within the scope of the XMM-Newton Distant Cluster Project. Both HST/ACS observations in the i775 and z850 passbands and VLT/FORS2 spectroscopy were obtained, in addition to follow-up Near-Infrared (NIR) imaging…
Molecular gas in NUclei of GAlaxies (NUGA). XII. The head-on collision in NGC 1961
Tacconi, L. J.; Hunt, L. K.; Schinnerer, E. +6 more
We present high-resolution maps of the CO(1-0) and CO(2-1) emission from the LINER 2 galaxy NGC 1961. This galaxy is unusual among late-type (Sc) disk galaxies in having a very large radial extent and inferred dynamical mass. We propose a head-on collision scenario to explain the perturbed morphology of this galaxy - both the off-centered rings an…
Quantifying the contamination by old main-sequence stars in young moving groups: the case of the Local Association
Montes, D.; Micela, G.; López-Santiago, J.
Context: The associations and moving groups of young stars are excellent laboratories for investigating stellar formation in the solar neighborhood. Previous results have confirmed that a non-negligible fraction of old main-sequence stars is present in the lists of possible members of young stellar kinematic groups. A detailed study of the propert…
Integral field optical spectroscopy of a representative sample of ULIRGs. II. Two-dimensional kpc-scale extinction structure
Colina, L.; Arribas, S.; García-Marín, M.
Context: Ultraluminous infrared galaxies are merging systems characterized for containing large amounts of dust and emitting the bulk of their energy in the infrared. Dust affects several of the observed properties derived from optical and near-IR rest-frame data, such as the stellar morphology and the ionized gas distribution. Systematic analysis…
The optical counterparts of accreting millisecond X-ray pulsars during quiescence
Covino, S.; D'Avanzo, P.; Campana, S. +3 more
Context: Eight accreting millisecond X-ray pulsars (AMXPs) are known to date. Although these systems are well studied at high energies, very little information is available for their optical/NIR counterparts. Up to now, only two of them, SAX J1808.4-3658 and IGR J00291+5934, have a secure multi-band detection of their optical counterparts in quies…
Hydrogen Lyman-α and Lyman-β spectral radiance profiles in the quiet Sun
Marsch, E.; Curdt, W.; Tian, H. +1 more
Aims: We extend earlier work by studying the line profiles of the hydrogen Lyman-α and Lyman-β lines in the quiet Sun. They were obtained quasi-simultaneously in a raster scan with a size of about 150'' × 120'' near disk center.
Methods: The self-reversal depths of the Ly-α and Ly-β profiles. we are quantified by measuring the maximum spectral…