Search Publications
Orbits of massive satellite galaxies - II. Bayesian estimates of the Milky Way and Andromeda masses using high-precision astrometry and cosmological simulations
Besla, Gurtina; Patel, Ekta; Mandel, Kaisey
In the era of high-precision astrometry, space observatories like the Hubble Space Telescope (HST) and Gaia are providing unprecedented 6D phase-space information of satellite galaxies. Such measurements can shed light on the structure and assembly history of the Local Group, but improved statistical methods are needed to use them efficiently. Her…
OCCASO - II. Physical parameters and Fe abundances of red clump stars in 18 open clusters
Jordi, C.; Casamiquela, L.; Anders, F. +13 more
Open clusters have long been used to study the chemodynamical evolution of the Galactic disc. This requires a homogeneously analysed sample covering a wide range of ages and distances. In this paper, we present the Open Clusters Chemical Abundances from Spanish Observatories (OCCASO) second data release. This comprises a sample of high-resolution …
Explosive events in active region observed by IRIS and SST/CRISP
Doyle, J. G.; Madjarska, M. S.; Huang, Z. +3 more
Transition-region explosive events (EEs) are characterized by non-Gaussian line profiles with enhanced wings at Doppler velocities of 50-150 km s-1. They are believed to be the signature of solar phenomena that are one of the main contributors to coronal heating. The aim of this study is to investigate the link of EEs to dynamic phenome…
A gravitationally boosted MUSE survey for emission-line galaxies at z ≳ 5 behind the massive cluster RCS 0224
Kneib, J. -P.; Richard, Johan; Smail, Ian +3 more
We present a Very Large Telescope/Multi Unit Spectroscopic Explorer (MUSE) survey of lensed high-redshift galaxies behind the z = 0.77 cluster RCS 0224-0002. We study the detailed internal properties of a highly magnified (µ ∼ 29) z = 4.88 galaxy seen through the cluster. We detect widespread nebular C IV λλ1548,1551 Å emission from this gal…
Broad-band X-ray spectral analysis of the Seyfert 1 galaxy GRS 1734-292
Harrison, F. A.; Stern, D.; Bianchi, S. +14 more
We discuss the broad-band X-ray spectrum of GRS 1734-292 obtained from non-simultaneous XMM-Newton and NuSTAR (Nuclear Spectroscopic Telescope Array) observations, performed in 2009 and 2014, respectively. GRS1734-292 is a Seyfert 1 galaxy, located near the Galactic plane at z = 0.0214. The NuSTAR spectrum (3-80 keV) is dominated by a primary powe…
The pebbles/boulders size distributions on Sais: Rosetta's final landing site on comet 67P/Churyumov-Gerasimenko
Jorda, L.; Lamy, P. L.; Lara, L. M. +53 more
By using the imagery acquired by the Optical, Spectroscopic, and Infrared Remote Imaging System Wide-Angle Camera (OSIRIS WAC), we prepare a high-resolution morphological map of the Rosetta Sais final landing site, characterized by an outcropping consolidated terrain unit, a coarse boulder deposit and a fine particle deposit. Thanks to the 0.014 m…
Spatial variations of brightness, colour and polarization of dust in comet 67P/Churyumov-Gerasimenko
Afanasiev, Viktor L.; Rosenbush, Vera K.; Ivanova, Oleksandra V. +2 more
We present post-perihelion photometric and polarimetric observations of comet 67P/Churyumov-Gerasimenko performed at the 6-m telescope of the SAO RAS in the g-sdss (465/65 nm), r-sdss (620/60 nm) and R filters. Observations in November and December 2015 and April 2016 covered the range of heliocentric distance 1.62-2.72 au and phase angle 33.2°-10…
Not that long time ago in the nearest galaxy: 3D slice of molecular gas revealed by a 110 yr old flare of Sgr A*
Sunyaev, R.; Churazov, E.; Ponti, G. +1 more
A powerful outburst of X-ray radiation from the supermassive black hole Sgr A* at the centre of the Milky Way is believed to be responsible for the illumination of molecular clouds in the central ∼100 pc of the Galaxy (Sunyaev, Markevitch & Pavlinsky; Koyama et al.). The reflected/reprocessed radiation comes to us with a delay corresponding to…
Red nuggets grow inside-out: evidence from gravitational lensing
Treu, Tommaso; Fassnacht, Christopher D.; Auger, Matthew W. +7 more
We present a new sample of strong gravitational lens systems where both the foreground lenses and background sources are early-type galaxies. Using imaging from Hubble Space Telescope (HST)/Advanced Camera for Studies (ACS) and Keck/NIRC2, we model the surface brightness distributions and show that the sources form a distinct population of massive…
The properties of energetically unbound stars in stellar clusters
Gieles, Mark; Zocchi, Alice; Claydon, Ian
Several Milky Way star clusters show a roughly flat velocity dispersion profile at large radii, which is not expected from models with a tidal cut-off energy. Possible explanations for this excess velocity include the effects of a dark matter halo, modified gravity theories and energetically unbound stars inside of clusters. These stars are known …