Search Publications
X-ray observation of ULAS J1120+0641, the most distant quasar at z = 7.08
Salvaterra, R.; Moretti, A.; Vignali, C. +6 more
We probe the emission mechanism of the accreting super massive black holes in the high redshift Universe and, to do this, we study the X-ray spectrum of ULAS1120+064, the highest redshift quasar detected so far at z = 7.085, which has been deeply observed (340 ks) by XMM-Newton. Despite the long integration time, the spectral analysis is limited b…
Photospheric supergranular flows and magnetic flux emergence
Stangalini, M.
A recent study carried out on high-sensitivity SUNRISE/IMAX data has reported about areas of limited flux emergence in the quiet Sun. By exploiting an independent and longer (four hours) data set acquired by Hinode/SOT, we investigate these regions in more detail by analysing their spatial distribution and relation with the supergranular flow. Our…
Discovery of periodic dips in the light curve of GX 13+1: the X-ray orbital ephemeris of the source
Robba, N. R.; Di Salvo, T.; Burderi, L. +3 more
Context. The bright low-mass X-ray binary (LMXB) GX 13+1 is one of the most peculiar Galactic binary systems. A periodicity of 24.27 d was observed in its power spectrum density obtained from data collected over 14 years by the All Sky Monitor (ASM) on board the Rossi X-ray Timing Explorer (RXTE).
Aims: To determine the first X-ray orbital ep…
A search for pulsations in the HgMn star HD 45975 with CoRoT photometry and ground-based spectroscopy
Auvergne, M.; Fossati, L.; Poretti, E. +28 more
The existence of pulsations in HgMn stars is still being debated. To provide the first unambiguous observational detection of pulsations in this class of chemically peculiar objects, the bright star
On the relation between metallicity and RGB color in HST/ACS data
de Jong, R. S.; Goudfrooij, P.; Bailin, J. +3 more
Context. The determination of stellar metallicity and its gradient in external galaxies is a difficult task, but crucial for the understanding of galaxy formation and evolution.
Aims: The color of the Red Giant Branch (RGB) can be used to determine metallicities of stellar populations that have only shallow photometry. We will quantify the re…
Impact of particles on the Planck HFI detectors: Ground-based measurements and physical interpretation
Bock, J. J.; Catalano, A.; Coulais, A. +31 more
The Planck High Frequency Instrument (HFI) surveyed the sky continuously from August 2009 to January 2012. Its noise and sensitivity performance were excellent (from 11 to 40 aW Hz-1), but the rate of cosmic-ray impacts on the HFI detectors was unexpectedly higher than in other instruments. Furthermore, collisions of cosmic rays with th…
SN 2005at - A neglected type Ic supernova at 10 Mpc
Kankare, E.; Kotak, R.; Monard, L. A. G. +7 more
We present a photometric and spectroscopic study of a reddened type Ic supernova (SN) 2005at. We report our results based on the available data of SN 2005at, including late-time observations from the Spitzer Space Telescope and the Hubble Space Telescope. In particular, late-time mid-infrared observations are something rare for type Ib/c SNe. In o…
A time-dependent photochemical model for Titan's atmosphere and the origin of H2O
Lara, L. M.; Lellouch, E.; Moreno, R. +2 more
Context. Titan's stratosphere contains oxygen compounds (CO, CO2, and H2O), implying an external source of oxygen whose nature is still uncertain. Recent observations from the Herschel Space Observatory using the HIFI and PACS instruments and the Cassini/CIRS, as well as steady-state photochemical modeling indicate that the a…
The coronal energy input from magnetic braiding
Yeates, A. R.; Welsch, B. T.; Bianchi, F. +1 more
We estimate the energy input into the solar corona from photospheric footpoint motions, using observations of a plage region by the Hinode Solar Optical Telescope. Assuming a perfectly ideal coronal evolution, two alternative lower bounds for the Poynting flux are computed based on field line footpoint trajectories, without requiring horizontal ma…
Differential emission measure analysis of active region cores and quiet Sun for the non-Maxwellian κ-distributions
Dzifčáková, E.; Dudík, J.; Mackovjak, Š.
Context. The non-Maxwellian κ-distributions have been detected in the solar wind and can explain intensities of some transition region lines. Presence of such distributions in the outer layers of the solar atmosphere influences the ionization and excitation equilibrium and widens the line contribution functions. This behavior may be reflected on t…