Search Publications
The Galaxy "Missing Dark Matter" NGC 1052-DF4 is Undergoing Tidal Disruption
Trujillo, Ignacio; Borlaff, Alejandro S.; Monelli, Matteo +4 more
The existence of long-lived galaxies lacking dark matter represents a challenge to our understanding of how galaxies form. Here, we present evidence that explains the lack of dark matter in one such galaxy: NGC 1052-DF4. Deep optical imaging of the system has detected tidal tails in this object caused by its interaction with its neighboring galaxy…
Evidence for reduced magnetic braking in polars from binary population models
Gänsicke, Boris T.; Belloni, Diogo; Pala, Anna F. +3 more
We present the first population synthesis of synchronous magnetic cataclysmic variables, called polars, taking into account the effect of the white dwarf (WD) magnetic field on angular momentum loss. We implemented the reduced magnetic braking (MB) model proposed by Li, Wu & Wickramasinghe into the Binary Stellar Evolution (BSE) code recently …
Collimated synchrotron threads linking the radio lobes of ESO 137-006
Govoni, F.; Ramaila, A. J. T.; Serra, P. +14 more
We present MeerKAT 1000 MHz and 1400 MHz observations of a bright radio galaxy in the southern hemisphere, ESO 137-006. The galaxy lies at the centre of the massive and merging Norma galaxy cluster. The MeerKAT continuum images (rms ∼0.02 mJy beam-1 at ∼10″ resolution) reveal new features that have never been seen in a radio galaxy befo…
The Red Supergiant Binary Fraction of the Large Magellanic Cloud
Drout, Maria R.; Massey, Philip; Levesque, Emily M. +2 more
The binary fraction of unevolved massive stars is thought to be 70%-100% but there are few observational constraints on the binary fraction of the evolved version of a subset of these stars, the red supergiants (RSGs). Here we identify a complete sample of RSGs in the Large Magellanic Cloud (LMC) using new spectroscopic observations and archival U…
Valley formation on early Mars by subglacial and fluvial erosion
Osinski, Gordon R.; Grau Galofre, Anna; Jellinek, A. Mark
The southern highlands of Mars are dissected by hundreds of valley networks, which are evidence that water once sculpted the surface. Characterizing the mechanisms of valley incision may constrain early Mars climate and the search for ancient life. Previous interpretations of the geological record require precipitation and surface water runoff to …
Fluvial Regimes, Morphometry, and Age of Jezero Crater Paleolake Inlet Valleys and Their Exobiological Significance for the 2020 Rover Mission Landing Site
Mangold, Nicolas; Quantin-Nataf, Cathy; Massé, Marion +5 more
Jezero crater has been selected as the landing site for the Mars 2020 Perseverance rover, because it contains a paleolake with two fan-deltas, inlet and outlet valleys. Using the data from the High Resolution Stereo Camera (HRSC) and the High Resolution Imaging Science Experiment (HiRISE), we conducted a quantitative geomorphological study of the …
To TDE or not to TDE: the luminous transient ASASSN-18jd with TDE-like and AGN-like qualities
Gromadzki, M.; Kochanek, C. S.; Foley, R. J. +26 more
We present the discovery of ASASSN-18jd (AT 2018bcb), a luminous optical/ultraviolet(UV)/X-ray transient located in the nucleus of the galaxy 2MASX J22434289-1659083 at z = 0.1192. Over the year after discovery, Swift UltraViolet and Optical Telescope (UVOT) photometry shows the UV spectral energy distribution of the transient to be well modelled …
Hic sunt dracones: Cartography of the Milky Way spiral arms and bar resonances with Gaia Data Release 2
Katz, D.; Haywood, M.; Gerhard, O. +5 more
In this paper we introduce a new method for analysing Milky Way phase-space which allows us to reveal the imprint left by the Milky Way bar and spiral arms on the stars with full phase-space data in Gaia Data Release 2. The unprecedented quality and extended spatial coverage of these data allowed us to discover six prominent stellar density struct…
The Gaia reference frame for bright sources examined using VLBI observations of radio stars
Lindegren, Lennart
Context. Positions and proper motions of Gaia sources are expressed in a reference frame that ideally should be non-rotating relative to distant extragalactic objects, coincident with the International Celestial Reference System (ICRS), and consistent across all magnitudes. For sources fainter than 16th magnitude, this is achieved through Gaia's d…
Fundamental parameters for 45 open clusters with Gaia DR2, an improved extinction correction and a metallicity gradient prior
Cantat-Gaudin, T.; Moitinho, A.; Paunzen, E. +4 more
Reliable fundamental parameters of open clusters (OCs) such as distance, age, and extinction are key to our understanding of Galactic structure and stellar evolution. In this work, we use Gaia Data Release 2 (DR2) to investigate 45 OCs listed in the New catalogue of optically visible open clusters and candidates (DAML) but with no previous astrome…