Search Publications
Stars with fast Galactic rotation observed in Gaia TGAS: a signature driven by the Perseus arm?
Grand, Robert J. J.; Siebert, Arnaud; Famaey, Benoit +3 more
We report on the detection of a small overdensity of stars in velocity space with systematically higher Galactocentric rotation velocity than the Sun by about 20 km s-1 in the Gaia Data Release 1 Tycho-Gaia astrometric solution data. We find these fast Galactic rotators more clearly outside of the Solar radius, compared to inside of the…
Semi-empirical seismic relations of A-F stars from COROT and Kepler legacy data
Moya, A.; Suárez, J. C.; García Hernández, A. +1 more
Asteroseismology is witnessing a revolution, thanks to high-precise asteroseismic space data (MOST, COROT, Kepler, BRITE) and their large ground-based follow-up programs. Those instruments have provided an unprecedented large amount of information, which allows us to scrutinize its statistical properties in the quest for hidden relations among pul…
The structure of Andromeda II dwarf spheroidal galaxy
del Pino, Andrés; Hidalgo, Sebastian L.; Łokas, Ewa L. +1 more
We analyse in detail the spatial distribution and kinematic properties of two different stellar populations in Andromeda II dwarf spheroidal galaxy. We obtained their detailed surface density maps together with their radial density profiles. The two populations differ not only in age and metallicity, but also in their spatial distribution and kine…
Exploring the progenitors of brightest cluster galaxies at z ∼ 2
Conselice, Christopher J.; Zhao, Dongyao; Aragón-Salamanca, Alfonso +5 more
We present a new method for tracing the evolution of brightest cluster galaxies (BCGs) from z ∼ 2 to z ∼ 0. We conclude on the basis of semi-analytical models that the best method to select BCG progenitors at z ∼ 2 is a hybrid environmental density and stellar mass ranking approach. Ultimately, we are able to retrieve 45 per cent of BCG progenitor…
Resolving the X-ray emission from the Lyman-continuum emitting galaxy Tol 1247-232
Kaaret, P.; Prestwich, A. H.; Brorby, M. +1 more
Chandra observations of the nearby, Lyman-continuum (LyC) emitting galaxy Tol 1247-232 resolve the X-ray emission and show that it is dominated by a point-like source with a hard spectrum (Γ = 1.6 ± 0.5) and a high luminosity [(9 ± 2) × 1040 erg s- 1]. Comparison with an earlier XMM-Newton observation shows flux variation of …
The nova-like nebular optical spectrum of V404 Cygni at the beginning of the 2015 outburst decay
Gandhi, P.; Tomsick, J. A.; Rossi, A. +7 more
We report on FORS2 optical spectroscopy of the black hole X-ray binary V404 Cygni, performed at the very beginning of its 2015 outburst decay, complemented by quasi-simultaneous Swift X-ray and ultraviolet as well as Rapid Eye Mountain near-infrared observations. Its peculiar spectrum is dominated by a wealth of emission signatures of H I, He I, a…
The X-ray continuum time-lags and intrinsic coherence in AGN
Papadakis, I. E.; Epitropakis, A.
We present the results from a systematic analysis of the X-ray continuum ('hard') time-lags and intrinsic coherence between the 2-4 keV and various energy bands in the 0.3-10 keV range, for 10 X-ray bright and highly variable active galactic nuclei (AGN). We used all available archival XMM-Newton data, and estimated the time-lags following Epitrop…
The 34S/32S isotopic ratio measured in the dust of comet 67P/Churyumov-Gerasimenko by Rosetta/COSIMA
Hilchenbach, M.; Hornung, K.; Kissel, J. +4 more
The isotopic ratio 34S/32S has been measured in cometary gas for a few comets, but it has only been measured in cometary dust by stardust. The dust measurements find a value of the ratio that is consistent with the Vienna Canyon Diablo Troilite value of 0.0442 within errors, but there is more spread in the values from cometar…
Three-dimensional illumination and thermal model of the Abydos region on comet 67P/Churyumov-Gerasimenko
Spohn, Tilman; Finke, Felix; Jorda, Laurent +9 more
On 2014 November 12 Rosetta's comet lander Philae arrived on the surface of Comet 67P/Churyumov-Gerasimenko. Among the data collected by the instruments on board are images from the panorama camera CIVA and the down looking camera ROLIS, as well as temperature measurements recorded by the sensors of the MUPUS experiment and by various housekeeping…
Unveiling slim accretion disc in AGN through X-ray and Infrared observations
Kaspi, Shai; Ho, Luis C.; Bian, Wei-Hao +7 more
In this work, which is a continuation of Castelló-Mor et al., we present new X-ray and infrared (IR) data for a sample of active galactic nuclei (AGN) covering a wide range in Eddington ratio over a small luminosity range. In particular, we rigorously explore the dependence of the optical-to-X-ray spectral index αOX and the IR-to-optica…