Search Publications
Deep Herschel PACS point spread functions
Abergel, A.; Bianchi, S.; Bocchio, M.
The knowledge of the point spread function (PSF) of imaging instruments represents a fundamental requirement for astronomical observations. The Herschel PACS PSFs delivered by the instrument control centre are obtained from observations of the Vesta asteroid, which provides a characterisation of the central part and, therefore, excludes fainter fe…
Scaling laws of coronal loops compared to a 3D MHD model of an active region
Peter, H.; Bingert, S.; Bourdin, Ph. -A.
Context. The structure and heating of coronal loops have been investigated for decades. Established scaling laws relate fundamental quantities like the loop apex temperature, pressure, length, and coronal heating.
Aims: We test these scaling laws against a large-scale 3D magneto-hydrodynamics (MHD) model of the solar corona, which became feas…
Testing the blazar sequence with the least luminous BL Lacertae objects
Capetti, A.; Raiteri, C. M.
In a previous paper, we proposed a new method to select low-power BL Lacs (LPBLs) based on mid-infrared emission and flux contrast through the Ca II spectral break; that study led to the selection of a complete sample formed by 34 LPBLs with 0.05 <z ≤ 0.15 and radio luminosities spanning the range log Lr = 39.2-41.5 [erg s-1
The gaseous debris disk of the white dwarf SDSS J1228+1040. HST/COS search for far-ultraviolet signatures
Rauch, T.; Werner, K.; Nagel, T. +1 more
Context. Gaseous and dust debris disks around white dwarfs (WDs) are formed from tidally disrupted planetary bodies. This offers an opportunity to determine the composition of exoplanetary material by measuring element abundances in the accreting WD's atmosphere. A more direct way to do this is through spectral analysis of the disks themselves.
Quantitative spectral analysis of the sdB star HD 188112: A helium-core white dwarf progenitor
Geier, S.; Heber, U.; Latour, M. +7 more
Context. HD 188112 is a bright (V = 10.2 mag) hot subdwarf B (sdB) star with a mass too low to ignite core helium burning and is therefore considered a pre-extremely low-mass (ELM) white dwarf (WD). ELM WDs (M ≲ 0.3 M⊙) are He-core objects produced by the evolution of compact binary systems.
Aims: We present in this paper a detaile…
Mapping the coronal hydrogen temperature in view of the forthcoming coronagraph observations by Solar Orbiter
Spadaro, D.; Dolei, S.; Ventura, R.
Context. Synergistic visible light and ultraviolet coronagraphic observations are essential to investigate the link of the Sun to the inner heliosphere through the study of the dynamic properties of the solar wind.
Aims: We perform spectroscopic mapping of the outer solar corona to constitute a statistically significant database of neutral hy…
Mid-infrared dust in two nearby radio galaxies, NGC 1316 (Fornax A) and NGC 612 (PKS 0131-36)
Horellou, C.; Jarrett, T. H.; Winkler, H. +1 more
Context. Most radio galaxies are hosted by giant gas-poor ellipticals, but some contain significant amounts of dust, which is likely to be of external origin.
Aims: In order to characterize the mid-IR properties of two of the most nearby and brightest merger-remnant radio galaxies of the Southern hemisphere,
Relationship between supergranulation flows, magnetic cancellation and network flares
Solanki, S. K.; Glassmeier, K. H.; Innes, D. E. +1 more
Context. Photospheric flows create a network of often mixed-polarity magnetic field in the quiet Sun, where small-scale eruptions and network flares are commonly seen.
Aims: The aim of this paper is (1) to describe the characteristics of the flows that lead to these energy releases, (2) to quantify the energy build up due to photospheric flow…
Possible interpretation of the precession of comet 67P/Churyumov-Gerasimenko
Jorda, L.; Lara, L. M.; Lamy, P. +52 more
Context. Data derived from the reconstruction of the nucleus shape of comet 67P/Churyumov-Gerasimenko (67P) from images of the OSIRIS camera onboard ROSETTA show evidence that the nucleus rotates in complex mode. First, the orientation of the spin axis is not fixed in an inertial reference frame, which suggests a precessing motion around the angul…
Observations of asymmetric velocity fields and gas cooling in the NGC 4636 galaxy group X-ray halo
Kaastra, Jelle; Finoguenov, Alexis; Fabian, Andrew +4 more
Aims: This study aims to probe the thermodynamic properties of the hot intragroup medium (IGM) plasma in the core regions of the NGC 4636 galaxy group by detailed measurements of several emission lines and their relative intensities.
Methods: We analyzed deep XMM-Newton Reflection Grating Spectrometer (RGS) data in five adjacent spectral…