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Angular momentum of z ∼ 1.5 galaxies and their local analogues with adaptive optics
Glazebrook, Karl; Fisher, Deanne B.; Obreschkow, Danail +9 more
We present stellar specific angular momentum j* measurements of two z ∼ 1.5 galaxies in the KGES sample and 12 DYNAMO z ∼ 0.1 analogues of high-redshift galaxies. We combine natural seeing integral field spectroscopic data to trace line emission out to high multiples of effective radius re, with adaptive optics assisted Keck/…
Light element variations within the different age-metallicity populations in the nucleus of the Sagittarius dwarf
Cadelano, Mario; Dalessandro, Emanuele; Sills, Alison +2 more
The cluster M54 lies at the centre of the Sagittarius dwarf spheroidal galaxy, and therefore may be the closest example of a nuclear star cluster. Either in situ star formation, inspiralling globular clusters, or a combination have been invoked to explain the wide variety of stellar sub-populations in nuclear star clusters. Globular clusters are k…
Image simulations for gravitational lensing with SKYLENS
Plazas, A. A.; Meneghetti, M.; Rhodes, J. +1 more
We present the latest version of the ray-tracing simulation code SKYLENS, which can be used to develop image simulations that reproduce strong lensing observations by any mass distribution with a high level of realism. Improvements of the code with respect to previous versions include the implementation of the multilens plane formalism, the use of…
Two kinematically distinct old globular cluster populations in the Large Magellanic Cloud
Piatti, Andrés E.; Cantat-Gaudin, Tristan; Alfaro, Emilio J.
We report results of proper motions of 15 known Large Magellanic Cloud (LMC) old globular clusters (GCs) derived from the Gaia DR2 data sets. When these mean proper motions are gathered with existent radial velocity measurements to compose the GCs' velocity vectors, we found that the projection of the velocity vectors on to the LMC plane and those…
Star formation quenching imprinted on the internal structure of naked red nuggets
van de Ven, Glenn; Yıldırım, Akın; Martín-Navarro, Ignacio
The formation and assembly process of massive galaxies is a combination of two phases: an initial in-situ-dominated one followed by an ex-situ-dominated evolution. Separating these two contributions is therefore crucial to understand the baryonic cycle within massive haloes. A recently discovered population of so-called naked red nuggets, galaxies…
Free-form GRALE reconstruction of Abell 2744: robustness of uncertainties against changes in lensing data
Medezinski, Elinor; Okabe, Nobuhiro; Liesenborgs, Jori +2 more
Abell 2744, a massive Hubble Frontier Fields merging galaxy cluster with many multiple images in the core has been the subject of many lens inversions using different methods. While most existing studies compare various inversion methods, we focus on a comparison of reconstructions that use different input lensing data. Since the quantity and qual…
Limits on a population of collisional-triples as progenitors of Type-Ia supernovae
Maoz, Dan; Hallakoun, Na'ama
The progenitor systems of Type-Ia supernovae (SNe Ia) are yet unknown. The collisional-triple SN Ia progenitor model posits that SNe Ia result from head-on collisions of binary white dwarfs (WDs), driven by dynamical perturbations by the tertiary stars in mild-hierarchical triple systems. To reproduce the Galactic SN Ia rate, at least ∼30-55 per c…
Kinetic Alfvén solitary waves in a plasma with two-temperature superthermal electron populations: the case of Saturn's magnetosphere
Singh, Manpreet; Saini, N. S.; Kourakis, I.
Thanks to the evidence provided by the Cassini spacecraft mission, it is now established that Saturn's magnetospheric plasma consists of various types of positive ions, as well as two distinct populations of electrons, at different temperatures. The electron population energy distributions are characterized by long suprathermal tails and have been…
The 11 yr of low activity of the magnetar XTE J1810-197
Pintore, Fabio; Mereghetti, Sandro; Esposito, Paolo +5 more
In 2003, the magnetar XTE J1810-197 started an outburst that lasted until early 2007. In the following 11 yr, the source stayed in a quiescent/low-activity phase. XTE J1810-197 is one of the closest magnetars, hence its X-ray properties can be studied in detail even in quiescence and an extended monitoring has been carried out to study its long-te…
Comprehensive abundance analysis of red giants in the open clusters Stock 2, NGC 2168, 6475, 6991, and 7762
Lambert, David L.; Reddy, Arumalla B. S.
We have analysed high-dispersion Echelle spectra (R = 60 000) of red giant members of five open clusters to derive abundances for many elements from Na to Eu. The [Fe/H] values are -0.06 ± 0.03 for Stock 2, -0.11 ± 0.03 for NGC 2168, -0.01 ± 0.03 for NGC 6475, 0.00 ± 0.03 for NGC 6991, and -0.07 ± 0.03 for NGC 7662. Sodium is enriched in the giant…