Search Publications
Fine-structure line deficit in S 140
Ossenkopf, V.; van der Tak, F. F. S.; Okada, Y. +5 more
Aims: We try to understand the gas heating and cooling in the S 140 star-forming region by spatially and spectrally resolving the distribution of the main cooling lines with GREAT/SOFIA and combining our data with existing ground-based and Herschel observations that trace the energy input and the density and temperature structure of the sourc…
The far-ultraviolet spectra of "cool" PG 1159 stars
Rauch, T.; Werner, K.; Kruk, J. W.
We present a comprehensive study of Far Ultraviolet Spectroscopic Explorer (FUSE) spectra (912-1190 Å) of two members of the PG 1159 spectral class, which consists of hydrogen-deficient (pre-) white dwarfs with effective temperatures in the range Teff = 75 000-200 000 K. As two representatives of the cooler objects, we have selected PG …
A study of purely astrometric selection of extragalactic point sources with Gaia
Fynbo, J. P. U.; Heintz, K. E.; Høg, E.
Context. Selection of extragalactic point sources, e.g., quasi-stellar objects (QSOs), is often hampered by significant selection effects causing existing samples to have rather complex selection functions.
Aims: We explore whether a purely astrometric selection of extragalactic point sources, e.g., QSOs, is feasible with the ongoing Gaia mis…
Coronal energy input and dissipation in a solar active region 3D MHD model
Peter, H.; Bingert, S.; Bourdin, Ph. -A.
Context. We have conducted a 3D MHD simulation of the solar corona above an active region (AR) in full scale and high resolution, which shows coronal loops, and plasma flows within them, similar to observations.
Aims: We want to find the connection between the photospheric energy input by field-line braiding with the coronal energy conversion…
Solar-cycle variations of the internetwork magnetic field
Faurobert, M.; Ricort, G.
Context. The quiet Sun exhibits a rich and complex magnetic structuring that is still not fully resolved or understood.
Aims: We intend to contribute to the debate about the origin of the internetwork magnetic fields and whether or not they are related to the global solar dynamo.
Methods: We analyzed center-to-limb polarization measureme…
Visible light and ultraviolet observations of coronal structures: physical properties of an equatorial streamer and modelling of the F corona
Spadaro, D.; Dolei, S.; Ventura, R.
The present work studies the characteristics of an equatorial streamer visible above the east limb of the Sun on March 2008, during the most recent minimum of solar activity. We analysed the visible light coronagraphic images of SOHO/LASCO and the ultraviolet observations in the H I Lyα spectral line obtained by SOHO/UVCS, and exploited the Dopple…
Differentiation signatures in the Flora region
Oszkiewicz, Dagmara; Włodarczyk, Ireneusz; Kankiewicz, Paweł +1 more
Context. Most asteroid families are very homogeneous in physical properties. Some show greater diversity, however. The Flora family is the most intriguing of them. The Flora family is spread widely in the inner main belt, has a rich collisional history, and is one of the most taxonomically diverse regions in the main belt. As a result of its proxi…
Planck revealed bulk motion of Centaurus A lobes
Nucita, A. A.; De Paolis, F.; Ingrosso, G. +8 more
Planck data towards the active galaxy Centaurus A are analyzed in the 70, 100 and 143 GHz bands. We find a temperature asymmetry of the northern radio lobe with respect to the southern one that clearly extends at least up to 5° from the Cen A center and diminishes towards the outer regions of the lobes. That transparent parameter - the temperature…
Deep near-infrared adaptive-optics observations of a young embedded cluster at the edge of the RCW 41 H II region
Zavagno, A.; Neichel, B.; Samal, M. R. +3 more
Aims: We investigate the star formation activity in a young star forming cluster embedded at the edge of the RCW 41 H ii region. As a complementary goal, we aim to demonstrate the gain provided by wide-field adaptive optics (WFAO) instruments to study young clusters.
Methods: We used deep, JHKs images from the newly commission…
Temperatures of dust and gas in S 140
Ossenkopf, V.; van der Tak, F. F. S.; Kramer, C. +4 more
Context. In dense parts of interstellar clouds (≥105 cm-3), dust and gas are expected to be in thermal equilibrium, being coupled via collisions. However, previous studies have shown that in the presence of intense radiation fields, the temperatures of the dust and gas may remain decoupled even at higher densities.
Aims:…