Search Publications
Oxygen in dense interstellar gas. The oxygen abundance of the star forming core ρ Ophiuchi A
Liseau, R.; Justtanont, K.
Context: Oxygen is the third most abundant element in the universe, but its chemistry in the interstellar medium is still not understood well.
Aims: To critically examine the entire oxygen budget, we initially attempt to estimate the abundance of atomic oxygen, O, in the only region where molecular oxygen, O{2}, has been detected to date.
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An extreme EXO: a type 2 QSO at z = 1.87
Akiyama, M.; Carrera, F. J.; Watson, M. G. +6 more
Aims: We aim to understand the multi-wavelength properties of 2XMM J123204+215255, the source with the most extreme X-ray-to-optical flux ratio amongst a sample of bright X-ray selected EXOs drawn from a cross-correlation of the 2XMMp catalogue with the SDSS-DR5 catalogue.
Methods: We use 2XMMp X-ray data, SDSS-DR5, NOT and UKIRT optical/NIR p…
A FEROS spectroscopic study of the extreme O supergiant He 3-759
Crowther, P. A.; Evans, C. J.
We present a study of the extreme O-type supergiant He 3-759 using new high-resolution FEROS data, revealing that it is a near spectroscopic twin of HD 151804 (O8 Iaf). We investigate the extinction towards He 3-759 using a variety of methods, revealing AV ∼ 4.7^m. If we assume He 3-759 has an identical absolute K-band magnitude to HD 1…
Neutral absorber dips in the periodic burster LMXB XB 1323-619 from Suzaku
Church, M. J.; Dotani, T.; Bałucińska-Church, M. +1 more
We present results of an observation with Suzaku of the dipping, periodic bursting low mass X-ray binary XB 1323-619. Using the energy band 0.8-70 keV, we show that the source spectrum is well-described as the emission of an extended accretion disk corona, plus a small contribution of blackbody emission from the neutron star. The dip spectrum is w…
INTEGRAL observations of the Perseus cluster
Paltani, S.; Eckert, D.
We present the results of a 500 ks observation of the Perseus cluster with INTEGRAL, with the aim of investigating the possible diffuse non-thermal component detected in a previous Chandra observation. In the 3-20 keV band with the JEM-X instrument, we detect the source with high significance and resolve it spatially. Above 20 keV with IBIS/ISGRI,…
Cluster and cluster galaxy evolution history from IR to X-ray observations of the young cluster RX J1257.2+4738 at z = 0.866
Ilbert, O.; Adami, C.; Gavazzi, R. +8 more
Context: The cosmic time around the z ~ 1 redshift range appears crucial in the cluster and galaxy evolution, since it is probably the epoch of the first mature galaxy clusters. Our knowledge of the properties of the galaxy populations in these clusters is limited because only a handful of z ~ 1 clusters are presently known.
Aims: In this fram…
Evolution of the cloud field and wind structure of Jupiter's highest speed jet during a huge disturbance
Sánchez-Lavega, A.; García-Melendo, E.; Pérez-Hoyos, S. +1 more
Aims: Despite the banded visual aspect of cloud patterns in Jupiter, high resolution images indicate that these regions are markedly turbulent. One region of particular interest is the north temperate belt (NTB) at 21° N planetocentric latitude, where the most intense Jovian jet resides with eastward peak speeds of 160-180 m s-1. Almost…
No first ionization potential fractionation in the active stars AR Piscium and AY Ceti
Sanz-Forcada, J.; Micela, G.; Affer, L.
Context: The comparison of coronal and photospheric abundances in cool stars is an essential question to resolve. In the Sun an enhancement of the elements with low first ionization potential (FIP) is observed in the corona with respect to the photosphere. Stars with high levels of activity seem to show a depletion of elements with low FIP when co…
Water masers in the Saturnian system
Gurvits, L. I.; Pogrebenko, S. V.; Mujunen, A. +11 more
Context: The presence of water has long been seen as a key condition for life in planetary environments. The Cassini spacecraft discovered water vapour in the Saturnian system by detecting absorption of UV emission from a background star. Investigating other possible manifestations of water is essential, one of which, provided physical conditions …
The ultraviolet flare at the center of the elliptical galaxy NGC 4278
Morelli, L.; Buson, L. M.; Beifiori, A. +5 more
Context: A large fraction of otherwise normal galaxies shows a weak nuclear activity. One of the signatures of the low-luminosity active galactic nuclei (LLAGNs) is ultraviolet variability which was serendipitously discovered in the center of some low-ionization nuclear emission-line region (LINER) galaxies.
Aims: There is a pressing need to a…