Search Publications
The homogeneity of chemical abundances in H II regions of the Magellanic Clouds
García-Rojas, J.; Esteban, C.; Rodríguez, M. +2 more
We use very deep spectra obtained with the Ultraviolet-Visual Echelle Spectrograph at the Very Large Telescope to derive physical conditions and chemical abundances of four H II regions of the Large Magellanic Cloud (LMC) and four H II regions of the Small Magellanic Cloud (SMC). The observations cover the spectral range 3100-10400 Å with a spectr…
A complex multiphase DLA associated with a compact group at z = 2.431 traces accretion, outflows, and tidal streams
Charlton, Jane C.; Kacprzak, Glenn G.; Churchill, Christopher W. +4 more
As part of our program to identify host galaxies of known z = 2-3 Mg II absorbers with the Keck Cosmic Web Imager (KCWI), we discovered a compact group giving rise to a z = 2.431 DLA with ultrastrong Mg II absorption in quasar field J234628+124859. The group consists of four star-forming galaxies within 8-28 kpc and v ~ 40-340 km s-1 of…
Kinematic footprint of the Milky Way spiral arms in Gaia EDR3
Pérez-Villegas, Angeles; Martinez-Medina, Luis; Peimbert, Antonio
The Milky Way spiral arms are well established from star counts as well as from the locus of molecular clouds and other young objects; however, they have only recently started to be observed from a kinematics point of view. Using the kinematics of thin disc stars in Gaia EDR3 around the extended solar neighbourhood, we create x-y projections colou…
Deep learning-based super-resolution and de-noising for XMM-newton images
Valtchanov, Ivan; Verdugo, Eva; Lieu, Maggie +6 more
The field of artificial intelligence based image enhancement has been rapidly evolving over the last few years and is able to produce impressive results on non-astronomical images. In this work, we present the first application of Machine Learning based super-resolution (SR) and de-noising (DN) to enhance X-ray images from the European Space Agenc…
zELDA: fitting Lyman alpha line profiles using deep learning
Gronke, Max; Saito, Shun; Bonoli, Silvia +2 more
We present zELDA (redshift Estimator for Line profiles of Distant Lyman Alpha emitters), an open source code to fit Lyman α (Ly α) line profiles. The main motivation is to provide the community with an easy to use and fast tool to analyse Ly α line profiles uniformly to improve the understating of Ly α emitting galaxies. zELDA is based on line pro…
Dark and luminous mass components of Omega Centauri from stellar kinematics
Zivick, Paul; Strigari, Louis E.; Evans, Addy J.
We combine proper motion data from Gaia EDR3 and HST with line-of-sight velocity data to study the stellar kinematics of the ω Cen globular cluster. Using a steady-state, axisymmetric dynamical model, we measure the distribution of both the dark and luminous mass components. Assuming both Gaussian and Navarro-Frenk-White mass profiles, depending o…
Constraining spinning primordial black holes with global 21-cm signal
Natwariya, Pravin Kumar; Nayak, Alekha C.; Srivastava, Tripurari
We study the upper projected bounds on the dark matter fraction in the form of the primordial black holes (PBHs) with a non-zero spin by using the absorption feature in the global 21-cm signal at redshift z ≈ 17. The mass and spin are fundamental properties of a black hole, and they can substantially affect the evaporation rate of the black hole. …
AGN accretion and black hole growth across compact and extended galaxy evolution phases
Kocevski, Dale D.; Aird, James; Coil, Alison L.
The extent of black hole growth during different galaxy evolution phases and the connection between galaxy compactness and active galactic nucleus (AGN) activity remain poorly understood. We use Hubble Space Telescope imaging of the CANDELS fields to identify star-forming and quiescent galaxies at z = 0.5-3 in both compact and extended phases and …
The effect of hierarchical structure of the surface dust layer on the modelling of comet gas production
Blum, J.; Hartogh, P.; Bentley, M. S. +3 more
A hierarchical model of microstructure of cometary dust seems to accurately capture the morphological complexity of these particles as observed by the Rosetta mission to the 67P/Churyumov-Gerasimenko. The main aim of this work is to investigate how uncertainties in the knowledge of the microstructure of the surface layer affect our estimates of ga…
Exoplanets in the Galactic context: planet occurrence rates in the thin disc, thick disc, and stellar halo of Kepler stars
Bashi, Dolev; Zucker, Shay
In order to gain a better understanding of planet formation and evolution, it is important to examine the statistics of exoplanets in the Galactic context. By combining information on stellar elemental abundances and kinematics, we constructed separate samples of Kepler stars according to their affiliation to the Galactic components of thin disc, …