Search Publications
A new method to identify subclasses among AGB stars using Gaia and 2MASS photometry
Mowlavi, N.; Lecoeur-Taïbi, I.; Lebzelter, T. +4 more
Aims: We explore the wealth of high-quality photometric data provided by data release 2 (DR2) of the Gaia mission for long-period variables (LPVs) in the Large Magellanic Cloud (LMC). Our goal is to identify stars of various types and masses along the asymptotic giant branch.
Methods: For this endeavour, we developed a new multi-band app…
The empirical Gaia G-band extinction coefficient
Arenou, F.; Babusiaux, C.; Sartoretti, P. +2 more
Context. The first Gaia data release unlocked the access to photometric information for 1.1 billion sources in the G-band. Yet, given the high level of degeneracy between extinction and spectral energy distribution for large passbands such as the Gaia G-band, a correction for the interstellar reddening is needed in order to exploit Gaia data.
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Solar cycle 24: An unusual polar field reversal
Janardhan, P.; Fujiki, K.; Ingale, M. +2 more
Context. It is well known that the polarity of the Sun's magnetic field reverses or flips around the maximum of each 11 year solar cycle. This is commonly known as polar field reversal and plays a key role in deciding the polar field strength at the end of a cycle, which is crucial for the prediction of the upcoming cycle.
Aims: We aim to inv…
The second-closest gamma-ray burst: sub-luminous GRB 111005A with no supernova in a super-solar metallicity environment
Gentile, Gianfranco; Paragi, Zsolt; Fynbo, Johan P. U. +17 more
We report the detection of the radio afterglow of a long gamma-ray burst (GRB) 111005A at 5-345 GHz, including very long baseline interferometry observations with a positional error of 0.2 mas. The afterglow position is coincident with the disc of a galaxy ESO 58049 at z = 0.01326 (∼1″ from its centre), which makes GRB 111005A the second-closest G…
Surround and Squash: the impact of superbubbles on the interstellar medium in Scorpius-Centaurus OB2
Roccatagliata, Veronica; Diehl, Roland; Siegert, Thomas +7 more
Context. Feedback by massive stars shapes the interstellar medium and is thought to influence subsequent star formation. The details of this process are under debate.
Aims: We exploited observational constraints on stars, gas, and nucleosynthesis ashes for the closest region with recent massive-star formation, Scorpius-Centaurus OB2, and comb…
Optical-NIR dust extinction towards Galactic O stars
Maíz Apellániz, J.; Barbá, R. H.
Context. O stars are excellent tracers of the intervening ISM because of their high luminosity, blue intrinsic SED, and relatively featureless spectra. We are currently conducting the Galactic O-Star Spectroscopic Survey (GOSSS), which is generating a large sample of O stars with accurate spectral types within several kpc of the Sun.
Aims: We…
New stellar encounters discovered in the second Gaia data release
Bailer-Jones, C. A. L.; Rybizki, J.; Fouesneau, M. +1 more
Passing stars may play an important role in the evolution of our solar system. We search for close stellar encounters to the Sun among all 7.2 million stars in Gaia DR2 that have six-dimensional phase space data. We characterize encounters by integrating their orbits through a Galactic potential and propagating the correlated uncertainties via a M…
The STAGGER-grid: A grid of 3D stellar atmosphere models. V. Synthetic stellar spectra and broad-band photometry
Thévenin, F.; Chiavassa, A.; Asplund, M. +4 more
Context. The surface structures and dynamics of cool stars are characterised by the presence of convective motions and turbulent flows which shape the emergent spectrum.
Aims: We used realistic three-dimensional (3D) radiative hydrodynamical simulations from the STAGGER-grid to calculate synthetic spectra with the radiative transfer code OPTI…
Dust attenuation and Hα emission in a sample of galaxies observed with Herschel at 0.6 < z < 1.6
Shirley, R.; Buat, V.; Boquien, M. +5 more
Context. Dust attenuation shapes the spectral energy distribution of galaxies. It is particularly true for dusty galaxies in which stars experience a heavy attenuation. The combination of UV to IR photometry with the spectroscopic measurement of the Hα recombination line helps to quantify dust attenuation of the whole stellar population and its wa…
Observations of fast-moving features in the debris disk of AU Mic on a three-year timescale: Confirmation and new discoveries
Ménard, F.; Avenhaus, H.; Augereau, J. -C. +62 more
Context. The nearby and young M star AU Mic is surrounded by a debris disk in which we previously identified a series of large-scale arch-like structures that have never been seen before in any other debris disk and that move outward at high velocities.
Aims: We initiated a monitoring program with the following objectives: (1) track the locat…