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Molecular gas in NUclei of GAlaxies (NUGA). VII. NGC 4569, a large scale bar funnelling gas into the nuclear region
Tacconi, L. J.; Hunt, L. K.; Krips, M. +8 more
This work is part of the NUGA survey of CO emission in nearby active galaxies. We present observations of NGC 4569, a member of the Virgo Cluster. We analyse the molecular gas distribution and kinematics in the central region and we investigate a possible link to the strong starburst present at the nucleus. 70% of the [ 1.1±0.2] ×109 M<…
The XMM large scale structure survey: optical vs. X-ray classifications of active galactic nuclei and the unified scheme
Maccagni, D.; Chiappetti, L.; Ebrero, J. +25 more
Aims:Our goal is to characterize AGN populations by comparing their X-ray and optical classifications within the framework of the standard orientation-based unified scheme.
Methods: We present a sample of 99 spectroscopically identified (R ≤ 22 mag) X-ray selected point sources in the XMM-LSS survey which are significantly detected (≥3σ) in th…
The XMM-Newton serendipitous survey. IV. Optical identification of the XMM-Newton medium sensitivity survey (XMS)
Pérez-Fournon, I.; Motch, C.; Bromage, G. E. +54 more
Aims:X-ray sources at intermediate fluxes (a few × 10-14 erg cm-2 s-1) with a sky density of ~100 deg-2 are responsible for a significant fraction of the cosmic X-ray background at various energies below 10 keV. The aim of this paper is to provide an unbiased and quantitative description of the X-ray sou…
Identification of Ne VIII lines in H-deficient (pre-) white dwarfs: a new tool to constrain the temperature of the hottest stars
Rauch, T.; Werner, K.; Kruk, J. W.
For the first time, we have identified Ne VIII absorption lines in far-UV spectra of the hottest known (T_eff ⪆ 150 000 K) hydrogen-deficient (pre-) white dwarfs of spectral type PG1159. They are of photospheric origin and can be matched by synthetic non-LTE line profiles. We also show that a number of UV and optical emission lines in these stars …
PPAK integral field spectroscopy survey of the Orion nebula. Data release
Alves, J.; Sánchez, S. F.; Martín-Gordón, D. +3 more
Aims:We present a low-resolution spectroscopic survey of the Orion nebula. The data are released for public use. We show the possible applications of this dataset analyzing some of the main properties of the nebula.
Methods: We perform an integral field spectroscopy mosaic of an area of ~5 arcmin× 6 arcmin centered on the Trapezium region of t…
Structure and dynamics of the class I young stellar object L1489 IRS
Hogerheijde, M. R.; Jørgensen, J. K.; Brinch, C. +1 more
Context: During protostellar collapse, conservation of angular momentum leads to the formation of an accretion disc. Little is known observationally about how and when the velocity field around the protostar shifts from infall-dominated to rotation-dominated.
Aims: We investigate this transition in the low-mass protostar L1489 IRS, which is kn…
A nanoflare model of quiet Sun EUV emission
Solanki, S. K.; Pauluhn, A.
Nanoflares have been proposed as the main source of heating of the solar corona. However, detecting them directly has so far proved elusive, and extrapolating to them from the properties of larger brightenings gives unreliable estimates of the power-law exponent α characterising their distribution. Here we take the approach of statistically modell…
The AGB stars of the intermediate-age LMC cluster NGC 1846. Variability and age determination
Lebzelter, T.; Wood, P. R.
Aims:We investigate variability and we model the pulsational behaviour of AGB variables in the intermediate-age LMC cluster NGC 1846.
Methods: Our own photometric monitoring has been combined with data from the MACHO archive to detect 22 variables among the cluster's AGB stars and to derive pulsation periods. According to the global parameters…
An integral field spectroscopic survey for high redshift damped Lyman-α galaxies
Jahnke, K.; Christensen, L.; Kelz, A. +3 more
Aims:We search for galaxy counterparts to damped Lyman-α absorbers (DLAs) at z > 2 towards nine quasars, which have 14 DLAs and 8 sub-DLAs in their spectra.
Methods: We use integral field spectroscopy to search for Lyα emission line objects at the redshifts of the absorption systems.
Results: Besides recovering two previously confirmed …
Clathrate hydrates as a sink of noble gases in Titan's atmosphere
Mousis, O.; Thomas, C.; Picaud, S. +1 more
We use a statistical thermodynamic approach to determine the composition of clathrate hydrates which may form from a multiple compound gas whose composition is similar to that of Titan's atmosphere. Assuming that noble gases are initially present in this gas phase, we calculate the ratios of xenon, krypton and argon to species trapped in clathrate…