Search Publications
Thermal inertia and roughness of the nucleus of comet 67P/Churyumov-Gerasimenko from MIRO and VIRTIS observations
Jorda, L.; Kührt, E.; Mottola, S. +17 more
Aims: Using data from the Rosetta mission to comet 67P/Churyumov-Gerasimenko, we evaluate the physical properties of the surface and subsurface of the nucleus and derive estimates for the thermal inertia (TI) and roughness in several regions on the largest lobe of the nucleus.
Methods: We have developed a thermal model to compute the tem…
INTEGRAL/SPI γ-ray line spectroscopy. Response and background characteristics
Diehl, Roland; Greiner, Jochen; Siegert, Thomas +7 more
Context. The space based γ-ray observatory INTEGRAL of the European Space Agency (ESA) includes the spectrometer instrument "SPI". This is a coded mask telescope featuring a 19-element Germanium detector array for high-resolution γ-ray spectroscopy, encapsulated in a scintillation detector assembly that provides a veto for background from charged …
Hypervelocity stars in the Gaia era. Runaway B stars beyond the velocity limit of classical ejection mechanisms
Heber, U.; Irrgang, A.; Kreuzer, S.
Context. Young massive stars in the halo are assumed to be runaway stars from the Galactic disk. Possible ejection scenarios are binary supernova ejections (BSE) or dynamical ejections from star clusters (DE). Hypervelocity stars (HVSs) are extreme runaway stars that are potentially unbound from the Galaxy. Powerful acceleration mechanisms such as…
Plasma source and loss at comet 67P during the Rosetta mission
Altwegg, K.; Carr, C.; Henri, P. +10 more
Context. The Rosetta spacecraft provided us with a unique opportunity to study comet 67P/Churyumov-Gerasimenko (67P) from a close perspective and over a 2-yr time period. Comet 67P is a weakly active comet. It was therefore unexpected to find an active and dynamic ionosphere where the cometary ions were largely dominant over the solar wind ions, e…
The stellar mass function of galaxies in Planck-selected clusters at 0.5 < z < 0.7: new constraints on the timescale and location of satellite quenching
Muzzin, Adam; Dahle, Håkon; Aussel, Hervé +4 more
We study the abundance of star-forming and quiescent galaxies in a sample of 21 clusters at 0.5 < z < 0.7, detected with the Planck satellite. Thanks to the large volume probed by Planck, these systems are extremely massive, and provide an excellent laboratory to study any environmental effects on their galaxies' properties. We measure the c…
Tensile strength of 67P/Churyumov-Gerasimenko nucleus material from overhangs
Jorda, L.; Lara, L. M.; Bertaux, J. -L. +52 more
We directly measured twenty overhanging cliffs on the surface of comet 67P/Churyumov-Gerasimenko extracted from the latest shape model and estimated the minimum tensile strengths needed to support them against collapse under the comet's gravity. We find extremely low strengths of around 1 Pa or less (1 to 5 Pa, when scaled to a metre length). The …
Ionised gas structure of 100 kpc in an over-dense region of the galaxy group COSMOS-Gr30 at z 0.7
Kollatschny, W.; Richard, J.; Brinchmann, J. +16 more
We report the discovery of a 104 kpc2 gaseous structure detected in [O II]λλ3727, 3729 in an over-dense region of the COSMOS-Gr30 galaxy group at z ~ 0.725 with deep MUSE Guaranteed Time Observations. We estimate the total amount of diffuse ionised gas to be of the order of (~5 ± 3) × 1010 M⊙ and explore…
The XXL Survey. XVII. X-ray and Sunyaev-Zel'dovich properties of the redshift 2.0 galaxy cluster XLSSC 122
Pierre, M.; Willis, J.; Carlstrom, J. E. +7 more
We present results from a 100 ks XMM-Newton observation of galaxy cluster XLSSC 122, the first massive cluster discovered through its X-ray emission at z ≈ 2. The data provide the first precise constraints on the bulk thermodynamic properties of such a distant cluster, as well as an X-ray spectroscopic confirmation of its redshift. We measure an a…
Discovery of 105 Hz coherent pulsations in the ultracompact binary IGR J16597-3704
Altamirano, D.; Sanna, A.; Degenaar, N. +15 more
We report the discovery of X-ray pulsations at 105.2 Hz (9.5 ms) from the transient X-ray binary IGR J16597-3704 using NuSTAR and Swift. The source was discovered by INTEGRAL in the globular cluster NGC 6256 at a distance of 9.1 kpc. The X-ray pulsations show a clear Doppler modulation that implies an orbital period of 46 min and a projected semi-…
Gaia GraL: Gaia DR2 gravitational lens systems. I. New quadruply imaged quasar candidates around known quasars
Djorgovski, S. G.; Surdej, J.; Ducourant, C. +12 more
Context. Multiply imaged gravitationally lensed quasars are among the most interesting and useful observable extragalactic phenomena. Because their study constitutes a unique tool in various fields of astronomy, they are highly sought, but difficult to find. Even in this era of all-sky surveys, discovering them remains a great challenge, with bare…