Search Publications
Photospheric downward plasma motions in the quiet Sun
Ruiz Cobo, B.; Quintero Noda, C.; Orozco Suárez, D.
Context. We analyze spectropolarimetric data taken with the Hinode spacecraft in quiet solar regions at the disk center. Distorted redshifted Stokes V profiles are found that show a characteristic evolution that always follows the same sequence of phases.
Aims: We aim to characterize the statistical properties of these events and recover the …
The Earliest Phases of Star formation (EPoS). Temperature, density, and kinematic structure of the star-forming core CB 17
Henning, Th.; Krause, O.; Beuther, H. +7 more
Context. The initial conditions for the gravitational collapse of molecular cloud cores and the subsequent birth of stars are still not well constrained. The characteristic cold temperatures (~10 K) in such regions require observations at sub-millimetre and longer wavelengths. The Herschel Space Observatory and complementary ground-based observati…
XMM-Newton and Swift observations of WZ Sagittae: spectral and timing analysis
Mukai, K.; Kuulkers, E.; Nucita, A. A. +3 more
Context. WZ Sagittae is the prototype object of a subclass of dwarf novae with rare and long (super)outbursts, in which a white dwarf primary accretes matter from a low mass companion. High-energy observations offer the possibility of a better understanding of the disk-accretion mechanism in WZ Sge-like binaries.
Aims: We used archival XMM-Ne…
The HH34 outflow as seen in [Fe ii] 1.64 µm by LBT-LUCI
Lorenzetti, D.; Nisini, B.; Antoniucci, S. +4 more
Context. Dense atomic jets from young stars copiously emit in [Fe ii] IR lines, which can, therefore, be used to trace the immediate environments of embedded protostars.
Aims: We want to investigate the morphology of the bright [Fe ii] 1.64 µm line in the jet of the source HH34 IRS and compare it with the most commonly used optical trac…
Confirming the thermal Comptonization model for black hole X-ray emission in the low-hard state
Maiolino, T.; Wilms, J.; Pottschmidt, K. +3 more
Hard X-ray spectra of black hole binaries in the low/hard state are well modeled by thermal Comptonization of soft seed photons by a corona-type region with kT ~ 50 keV and optical depth around 1. Previous spectral studies of 1E 1740.7-2942, including both the soft and the hard X-ray bands, were always limited by gaps in the spectra or by a combin…
The HIFI spectral survey of AFGL 2591 (CHESS). II. Summary of the survey
Ceccarelli, C.; van der Tak, F. F. S.; Helmich, F. P. +3 more
Aims: This paper presents the richness of submillimeter spectral features in the high-mass star forming region AFGL 2591.
Methods: As part of the Chemical Herschel Survey of Star Forming Regions (CHESS) key programme, AFGL 2591 was observed by the Herschel (HIFI) instrument. The spectral survey covered a frequency range from 480 to 1240 …
The extended structure of the dwarf irregular galaxy Sagittarius
Bellazzini, M.; Galleti, S.; Testa, V. +6 more
We present a detailed study of the stellar and H i structure of the dwarf irregular galaxy Sagittarius. We use new deep and wide field photometry to trace the surface brightness profile of the galaxy out to ≃5.0' (corresponding to ≃1600 pc) and down to µV ≃ 30.0 mag/arcsec2, thus showing that the stellar body of the gal…
Magnitude-range brightness variations of overactive K giants
Strassmeier, K. G.; Granzer, T.; Kriskovics, L. +4 more
Context. Decades-long, phase-resolved photometry of overactive spotted cool stars has revealed that their long-term peak-to-peak light variations can be as large as one magnitude. Such brightness variations are too large to be solely explained by rotational modulation and/or a cyclic, or pseudo-cyclic, waxing and waning of surface spots and facula…
Multiwavelength campaign on Mrk 509. XIV. Chandra HETGS spectra
Kaastra, J. S.; Kriss, G. A.; Arav, N. +14 more
Context. We present in this paper the results of a 270 ks Chandra HETGS observation in the context of a large multiwavelength campaign on the Seyfert galaxy Mrk 509.
Aims: The HETGS spectrum allows us to study the high ionisation warm absorber and the Fe-K complex in Mrk 509. We search for variability in the spectral properties of the source …
An updated maximum likelihood approach to open cluster distance determination
Luri, X.; Arenou, F.; Masana, E. +1 more
Aims: An improved method for estimating distances to open clusters is presented and applied to Hipparcos data for the Pleiades and the Hyades. The method is applied in the context of the historic Pleiades distance problem, with a discussion of previous criticisms of Hipparcos parallaxes. This is followed by an outlook for Gaia, where the impr…