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Detecting stars, galaxies, and asteroids with Gaia
de Bruijne, J. H. J.; Hestroffer, D.; Krone-Martins, A. +3 more
Context. Gaia is Europe's space astrometry mission, aiming to make a three-dimensional map of 1000 million stars in our Milky Way to unravel its kinematical, dynamical, and chemical structure and evolution.
Aims: We present a study of Gaia's detection capability of objects, in particular non-saturated stars, double stars, unresolved external …
Iron K and Compton hump reverberation in SWIFT J2127.4+5654 and NGC 1365 revealed by NuSTAR and XMM-Newton
Harrison, F. A.; Stern, D.; Zhang, W. W. +13 more
In the past five years, a flurry of X-ray reverberation lag measurements of accreting supermassive black holes have been made using the XMM-Newton telescope in the 0.3-10 keV energy range. In this work, we use the NuSTAR (Nuclear Spectroscopic Telescope Array) telescope to extend the lag analysis up to higher energies for two Seyfert galaxies, SWI…
IRIS observations of the Mg ii h and k lines during a solar flare
Fletcher, L.; Qiu, J.; Simões, P. J. A. +1 more
The bulk of the radiative output of a solar flare is emitted from the chromosphere, which produces enhancements in the optical and UV continuum, and in many lines, both optically thick and thin. We have, until very recently, lacked observations of two of the strongest of these lines: the Mg ii h and k resonance lines. We present a detailed study o…
Spatial and diurnal variation of water outgassing on comet 67P/Churyumov-Gerasimenko observed from Rosetta/MIRO in August 2014
Jorda, L.; Sierks, H.; Keller, H. U. +23 more
Aims: We present the spatial and diurnal variation of water outgassing on comet 67P/Churyumov-Gerasimenko using the HO rotational transition line at 556.936 GHz observed from Rosetta/MIRO in August 2014.
Methods: The water line was analyzed with a non-LTE radiative transfer model and an optimal estimation method to retrieve the HO outgas…
Tracing the conversion of gas into stars in Young Massive Cluster Progenitors
Bastian, N.; Longmore, S. N.; Kruijssen, J. M. D. +5 more
Whilst young massive clusters (YMCs; M ≳ 104 M⊙, age ≲ 100 Myr) have been identified in significant numbers, their progenitor gas clouds have eluded detection. Recently, four extreme molecular clouds residing within 200 pc of the Galactic Centre have been identified as having the properties thought necessary to form YMCs. Her…
The Formation of IRIS Diagnostics. V. A Quintessential Model Atom of C II and General Formation Properties of the C II Lines at 133.5 nm
Carlsson, Mats; Rathore, Bhavna
The C ii 133.5 {nm} lines are important observables for the NASA/SMEX mission Interface Region Imaging Spectrograph. To make three-dimensional (3D) non-LTE radiative transfer computationally feasible, it is crucial to have a model atom with as few levels as possible while retaining the main physical processes. We here develop such a model atom and…
The origin of ultrafast outflows in AGN: Monte Carlo simulations of the wind in PDS 456
Done, Chris; Gandhi, Poshak; Takahashi, Tadayuki +4 more
Ultrafast outflows (UFOs) are seen in many AGN, giving a possible mode for AGN feedback on to the host galaxy. However, the mechanism(s) for the launch and acceleration of these outflows are currently unknown, with UV line driving apparently strongly disfavoured as the material along the line of sight is so highly ionized that it has no UV transit…
Magnetic Untwisting in Solar Jets that Go into the Outer Corona in Polar Coronal Holes
Moore, Ronald L.; Sterling, Alphonse C.; Falconer, David A.
We study 14 large solar jets observed in polar coronal holes. In EUV movies from the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA), each jet appears similar to most X-ray jets and EUV jets that erupt in coronal holes; but each is exceptional in that it goes higher than most, so high that it is observed in the outer corona beyond 2.…
Cool dust heating and temperature mixing in nearby star-forming galaxies
Helou, G.; Boquien, M.; Bianchi, S. +20 more
Physical conditions of the interstellar medium in galaxies are closely linked to the ambient radiation field and the heating of dust grains. In order to characterize dust properties in galaxies over a wide range of physical conditions, we present here the radial surface brightness profiles of the entire sample of 61 galaxies from Key Insights into…
The Absence of an Environmental Dependence in the Mass-Metallicity Relation at z = 2
Kewley, Lisa J.; Kacprzak, Glenn G.; Glazebrook, Karl +10 more
We investigate the environmental dependence of the mass-metallicity relation at z = 2 with MOSFIRE/Keck as part of the ZFIRE survey. Here, we present the chemical abundance of a Virgo-like progenitor at z = 2.095 that has an established red sequence. We identified 43 cluster (< z> =2.095+/- 0.004) and 74 field galaxies (< z> =2.195+/- …