Search Publications
Dust properties in H II regions in M 33
Boquien, M.; De Looze, I.; Braine, J. +11 more
Context. The infrared emission (IR) of the interstellar dust has been claimed to be a tracer of the star formation rate. However, the conversion of the IR emission into star formation rate can be strongly dependent on the physical properties of the dust, which are affected by the environmental conditions where the dust is embedded.
Aims: We s…
Ortho-to-para ratio of NH2. Herschel-HIFI observations of ortho- and para-NH2 rotational transitions towards W31C, W49N, W51, and G34.3+0.1
Persson, C. M.; Gerin, M.; Herbst, E. +10 more
We have used the Herschel-HIFI instrument to observe the two nuclear spin symmetries of amidogen (NH2) towards the high-mass star-forming regions W31C (G10.6-0.4), W49N (G43.2-0.1), W51 (G49.5-0.4), and G34.3+0.1. The aim is to investigate the ratio of nuclear spin types, the ortho-to-para ratio (OPR) of NH2 in the translucen…
Model-independent characterisation of strong gravitational lenses
Bartelmann, M.; Wagner, J.
We develop a new approach to extracting model-independent information from observations of strong gravitational lenses. The approach is based on the generic properties of images near the fold and cusp catastrophes in caustics and critical curves. The observables we used are the relative image positions, the magnification ratios and ellipticities o…
Evolution of active region outflows throughout an active region lifetime
Poletto, G.; Zangrilli, L.
Context. We have shown previously that SOHO/UVCS data allow us to detect active region (AR) outflows at coronal altitudes higher than those reached by other instrumentation. These outflows are thought to be a component of the slow solar wind.
Aims: Our purpose is to study the evolution of the outflows in the intermediate corona from AR 8100, …
Constraints on the H2O formation mechanism in the wind of carbon-rich AGB stars
Blommaert, J. A. D. L.; De Ridder, J.; de Koter, A. +13 more
Context. The recent detection of warm H2O vapor emission from the outflows of carbon-rich asymptotic giant branch (AGB) stars challenges the current understanding of circumstellar chemistry. Two mechanisms have been invoked to explain warm H2O vapor formation. In the first, periodic shocks passing through the medium immediate…
Searching for filaments and large-scale structure around DAFT/FADA clusters
Adami, C.; Martinet, N.; Durret, F. +6 more
Context. Clusters of galaxies are located at the intersection of cosmic filaments and are still accreting galaxies and groups along these preferential directions. However, because of their relatively low contrast on the sky, filaments are difficult to detect (unless a large amount of spectroscopic data are available), and unambiguous detections ha…
Characterisation of red supergiants in the Gaia spectral range
Negueruela, Ignacio; González-Fernández, Carlos; Dorda, Ricardo
Context. The infrared calcium triplet and its nearby spectral region have been used for spectral and luminosity classification of late-type stars, but the samples of cool supergiants (CSGs) used have been very limited (in size, metallicity range, and spectral types covered). The spectral range of the Gaia Radial Velocity Spectrograph (RVS) covers …
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