Search Publications
Broadband X-ray observations of four gamma-ray narrow-line Seyfert 1 galaxies
Piconcelli, E.; Foschini, L.; Pogge, R. W. +4 more
Narrow-line Seyfert 1 galaxies (NLS1s) is one of the few classes of active galactic nuclei harboring powerful relativistic jets and detected in γ-rays. NLS1s are well-known X-ray sources. While in non-jetted sources the origin of this X-ray emission may be a hot corona surrounding the accretion disk, in jetted objects, especially beamed ones, the …
Iron abundance distribution in the hot gas of merging galaxy clusters
Urdampilleta, I.; Simionescu, A.; Kaastra, J. S. +4 more
We present XMM-Newton/EPIC observations of six merging galaxy clusters and study the distributions of their temperature, iron (Fe) abundance and pseudo-entropy along the merging axis. For the first time, we focused simultaneously, and in a comprehensive way, on the chemical and thermodynamic properties of the newly collided intra cluster medium (I…
A massive nebula around the luminous blue variable star RMC 143 revealed by ALMA
Paladini, R.; Umana, G.; Mehner, A. +11 more
The luminous blue variable (LBV) RMC 143 is located in the outskirts of the 30 Doradus complex, a region rich with interstellar material and hot luminous stars. We report the 3σ sub-millimetre detection of its circumstellar nebula with ALMA. The observed morphology in the sub-millimetre is different than previously observed with HST and ATCA in th…
Gaia DR2 white dwarfs in the Hercules stream
Rebassa-Mansergas, Alberto; Althaus, Leandro G.; Torres, Santiago +5 more
Aims: We analyzed the velocity space of the thin- and thick-disk Gaia white dwarf population within 100 pc by searching for signatures of the Hercules stellar stream. We aimed to identify objects belonging to the Hercules stream, and by taking advantage of white dwarf stars as reliable cosmochronometers, to derive a first age distribution.
Accurate stellar parameters and distance to two evolved eclipsing binary systems, OGLE-BLG-ECL-123903 and OGLE-BLG-ECL-296596, towards the Galactic bulge
Soszyński, I.; Smolec, R.; Thompson, I. B. +15 more
Aims: Our aim is to obtain high-accuracy measurements of the physical and orbital parameters of two evolved eclipsing binary systems, and to use these measurements to study their evolutionary status. We also aim to derive the distances to the systems by using a surface brightness-colour relation and compare these distances with the measuremen…
Interferometric observations of SiO thermal emission in the inner wind of M-type AGB stars IK Tauri and IRC+10011
Alcolea, J.; Bujarrabal, V.; Castro-Carrizo, A. +2 more
Context. Asymptotic giant branch (AGB) stars go through a process of strong mass loss that involves pulsations of the atmosphere, which extends to a region in which the conditions are adequate for dust grains to form. Radiation pressure acts on these grains which, coupled to the gas, drive a massive outflow. The details of this process are not cle…
Classification of low-luminosity stellar X-ray sources in the field of the Draco dwarf spheroidal galaxy
Stelzer, Beate; Sasaki, Manami; Saeedi, Sara +1 more
Aims: A previous study of the X-ray luminosity function of the X-ray sources in the Draco dwarf spheroidal (dSph) galaxy field indicates the presence of a population of unknown X-ray sources in the soft energy range of 0.5-2 keV. In 2015, there were twenty-six further deep XMM-Newton observations of Draco dSph, providing an opportunity for a …
Comparison of neutral outgassing of comet 67P/Churyumov-Gerasimenko inbound and outbound beyond 3 AU from ROSINA/DFMS
Wurz, P.; Altwegg, K.; Berthelier, J. J. +16 more
Context. Pre-equinox measurements of comet 67P/Churyumov-Gerasimenko with the mass spectrometer ROSINA/DFMS on board the Rosetta spacecraft revealed a strongly heterogeneous coma. The abundances of major and various minor volatile species were found to depend on the latitude and longitude of the nadir point of the spacecraft. The observed time var…
A study of accretion and disk diagnostics in the NGC 2264 cluster
Alencar, Silvia H. P.; Calvet, Nuria; Sousa, Alana P. +3 more
Context. Understanding disk dissipation is essential for studying how planets form. Disk gaps and holes, which almost correspond to dust-free regions, are inferred from infrared observations of T Tauri stars (TTS), indicating the existence of a transitional phase between thick accreting disks and debris disks. Transition disks are usually referred…
Analysis of a long-lived, two-cell lightning storm on Saturn
Gurnett, D. A.; Kurth, W. S.; Delcroix, M. +4 more
Lightning storms in Saturn's atmosphere can last for a few days up to several months. In this paper we analyze a lightning storm that raged for seven and a half months at a planetocentric latitude of 35° south from the end of November 2007 until mid-July 2008. Thunderstorms observed by the Cassini spacecraft before this time were characterized by …