Search Publications
Gaia Data Release 1. Open cluster astrometry: performance, limitations, and future prospects
Prusti, T.; Mazeh, T.; Zucker, S. +589 more
Context. The first Gaia Data Release contains the Tycho-Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry, the proper motion and parallax are calculated using HIPPARCOS and Tycho-2 positions in 1991.25 as prior information.
Aims: We investigate the scientific potential a…
Coupling hydrodynamics with comoving frame radiative transfer. I. A unified approach for OB and WR stars
Hamann, W. -R.; Sander, A. A. C.; Shenar, T. +2 more
Context. For more than two decades, stellar atmosphere codes have been used to derive the stellar and wind parameters of massive stars. Although they have become a powerful tool and sufficiently reproduce the observed spectral appearance, they can hardly be used for more than measuring parameters. One major obstacle is their inconsistency between …
ATLASGAL-selected massive clumps in the inner Galaxy. III. Dust continuum characterization of an evolutionary sample
König, C.; Menten, K. M.; Csengeri, T. +8 more
Context. Massive-star formation and the processes involved are still poorly understood. The ATLASGAL survey provides an ideal basis for detailed studies of large numbers of massive-star forming clumps covering the whole range of evolutionary stages. The ATLASGAL Top100 is a sample of clumps selected by their infrared and radio properties to be rep…
The X-ray properties of z 6 luminous quasars
Brandt, W. N.; Moretti, A.; Vignali, C. +2 more
We present a systematic analysis of X-ray archival data of all the 29 quasars (QSOs) at z> 5.5 observed so far with Chandra, XMM-Newton and Swift-XRT, including the most-distant quasar ever discovered, ULAS J1120+0641 (z = 7.08). This study allows us to place constraints on the mean spectral properties of the primordial population of luminous T…
Hot Stuff for One Year (HSOY). A 583 million star proper motion catalogue derived from Gaia DR1 and PPMXL
Demleitner, M.; Bastian, U.; Altmann, M. +2 more
Context. Recently, the first installment of data from the ESA Gaia astrometric satellite mission (Gaia DR1) was released, containing positions of more than 1 billion stars with unprecedented precision. This release contains the proper motions and parallaxes, however, for only a subset of 2 million objects. The second release will include those qua…
An HST/COS legacy survey of high-velocity ultraviolet absorption in the Milky Way's circumgalactic medium and the Local Group
Wakker, B. P.; Lehner, N.; Muzahid, S. +9 more
Context. The Milky Way is surrounded by large amounts of diffuse gaseous matter that connects the stellar body of our Galaxy with its large-scale Local Group (LG) environment.
Aims: To characterize the absorption properties of this circumgalactic medium (CGM) and its relation to the LG we present the so-far largest survey of metal absorption …
VLBI-Gaia offsets favor parsec-scale jet direction in active galactic nuclei
Petrov, L.; Kovalev, Y. Y.; Plavin, A. V.
Context. The data release 1 (DR1) of milliarcsecond-scale accurate optical positions of stars and galaxies was recently published by the space mission Gaia.
Aims: We study the offsets of highly accurate absolute radio (very long baseline interferometry, VLBI) and optical positions of active galactic nuclei (AGN) to see whether or not a signat…
Lyman continuum escape fraction of faint galaxies at z 3.3 in the CANDELS/GOODS-North, EGS, and COSMOS fields with LBC
Ryan, R. E.; O'Connell, R. W.; Dickinson, M. +41 more
Context. The reionization of the Universe is one of the most important topics of present-day astrophysical research. The most plausible candidates for the reionization process are star-forming galaxies, which according to the predictions of the majority of the theoretical and semi-analytical models should dominate the H I ionizing background at z …
On the kinematic detection of accreted streams in the Gaia era: a cautionary tale
Haywood, M.; Combes, F.; Gómez, A. +4 more
The ΛCDM cosmological scenario predicts that our Galaxy should contain hundreds of stellar streams in the solar vicinity, fossil relics of the merging history of the Milky Way and more generally of the hierarchical growth of galaxies. Because of the mixing time scales in the inner Galaxy, it has been claimed that these streams should be difficult …
The WISSH quasars project. III. X-ray properties of hyper-luminous quasars
Fiore, F.; Bianchi, S.; Martocchia, S. +14 more
We performed a survey of the X-ray properties of 41 objects from the WISE/SDSS selected hyper-luminous (WISSH) quasars sample, which includes 86 broad-line quasars with bolometric luminosity LBol ≳ 2 × 1047 erg s-1 shining at z 2-4. We used both proprietary and archival Chandra and XMM-Newton observations. Twenty-o…