Search Publications
The dynamically selected stellar halo of the Galaxy with Gaia and the tilt of the velocity ellipsoid
Helmi, Amina; Veljanoski, Jovan; Breddels, Maarten A. +1 more
Aims: We study the dynamical properties of halo stars located in the solar neighbourhood. Our goal is to explore how the properties of the halo depend on the selection criteria used to define a sample of halo stars. Once this is understood, we proceed to measure the shape and orientation of the halo's velocity ellipsoid and we use this inform…
The GALAH survey: properties of the Galactic disc(s) in the solar neighbourhood
Freeman, K. C.; Da Costa, G. S.; Stello, D. +26 more
Using data from the GALAH pilot survey, we determine properties of the Galactic thin and thick discs near the solar neighbourhood. The data cover a small range of Galactocentric radius (7.9 ≲ R_GC ≲ 9.5 kpc), but extend up to 4 kpc in height from the Galactic plane, and several kpc in the direction of Galactic anti-rotation (at longitude 260° ≤ ℓ …
Discovery of massive star formation quenching by non-thermal effects in the centre of NGC 1097
Prieto, M. A.; Tabatabaei, F. S.; Fernández-Ontiveros, J. A. +1 more
Observations show that massive star formation quenches first at the centres of galaxies. To understand quenching mechanisms, we investigate the thermal and non-thermal energy balance in the central kpc of NGC 1097—a prototypical galaxy undergoing quenching—and present a systematic study of the nuclear star formation efficiency and its dependencies…
The MUSE Hubble Ultra Deep Field Survey. XII. Mg II emission and absorption in star-forming galaxies
Feltre, Anna; Bacon, Roland; Tresse, Laurence +18 more
The physical origin of the near-ultraviolet Mg II emission remains an underexplored domain, unlike more typical emission lines that are detected in the spectra of star-forming galaxies. We explore the nebular and physical properties of a sample of 381 galaxies between 0.70 < z < 2.34 drawn from the MUSE Hubble Ultra Deep Survey. The spectra …
The magnetic nature of umbra-penumbra boundary in sunspots
Jurčák, J.; Schlichenmaier, R.; Rezaei, R. +2 more
Context. Sunspots are the longest-known manifestation of solar activity, and their magnetic nature has been known for more than a century. Despite this, the boundary between umbrae and penumbrae, the two fundamental sunspot regions, has hitherto been solely defined by an intensity threshold. Aim. Here, we aim at studying the magnetic nature of umb…
Characterization of the HD 219134 multi-planet system II. Stellar-wind sputtered exospheres in rocky planets b & c
Petit, P.; Vidotto, A. A.; Murthy, J. +6 more
We present a 3D study of the formation of refractory-rich exospheres around the rocky planets HD219134b and c. These exospheres are formed by surface particles that have been sputtered by the wind of the host star. The stellar wind properties are derived from magnetohydrodynamic simulations, which are driven by observationally-derived stellar magn…
The star formation law at GMC scales in M33, the Triangulum galaxy
Smith, Matthew W. L.; Williams, Thomas G.; Gear, Walter K.
We present a high spatial resolution study, on scales of ∼100 pc, of the relationship between star formation rate (SFR) and gas content within Local Group galaxy M33. Combining deep SCUBA-2 observations with archival GALEX, SDSS, WISE, Spitzer, and submillimetre Herschel data, we are able to model the entire SED from UV to sub-mm wavelengths. We c…
The Gaia-ESO Survey: a kinematical and dynamical study of four young open clusters
Gilmore, G.; Bayo, A.; Koposov, S. E. +32 more
Context. The origin and dynamical evolution of star clusters is an important topic in stellar astrophysics. Several models have been proposed in order to understand the formation of bound and unbound clusters and their evolution, and they can be tested by examining the kinematical and dynamical properties of clusters over a wide range of ages and …
A high-density relativistic reflection origin for the soft and hard X-ray excess emission from Mrk 1044
Fabian, A. C.; Pinto, C.; Misra, R. +7 more
We present the first results from a detailed spectral-timing analysis of a long (∼130 ks) XMM-Newton observation and quasi-simultaneous NuSTAR and Swift observations of the highly accreting narrow-line Seyfert 1 galaxy Mrk 1044. The broad-band (0.3-50 keV) spectrum reveals the presence of a strong soft X-ray excess emission below ∼1.5 keV, iron K<…
The VANDELS survey: dust attenuation in star-forming galaxies at z = 3-4
Cimatti, A.; Elbaz, D.; Cullen, F. +15 more
We present the results of a new study of dust attenuation at redshifts 3 < z < 4 based on a sample of 236 star-forming galaxies from the VANDELS spectroscopic survey. Motivated by results from the First Billion Years (FiBY) simulation project, we argue that the intrinsic spectral energy distributions (SEDs) of star-forming galaxies at these …