Search Publications
The globular clusters and star formation history of the isolated, quiescent ultra-diffuse galaxy DGSAT I
van Dokkum, Pieter G.; Forbes, Duncan A.; Romanowsky, Aaron J. +6 more
We investigate the isolated, quiescent ultra-diffuse galaxy (UDG) DGSAT I and its globular cluster (GC) system using two orbits of Hubble Space Telescope Advanced Camera for Surveys imaging in the F606W and F814W filters. This is the first study of GCs around a UDG in a low-density environment. DGSAT I was previously found to host an irregular blu…
Dynamical state of galaxy clusters evaluated from X-ray images
Yuan, Z. S.; Han, J. L.; Wen, Z. L.
X-ray images of galaxy clusters often show disturbed structures that are indications of cluster mergers. To complement our previous work on the dynamical state of 964 clusters observed by Chandra, we process the X-ray images for 1308 clusters from XMM-Newton archival data, together with the images of 22 clusters newly released by Chandra, and we e…
The detailed chemical abundance patterns of accreted halo stars from the optical to infrared
Hawkins, Keith; Lucey, Madeline; Jofré, Paula +3 more
Understanding the assembly of our Galaxy requires us to also characterize the systems that helped build it. In this work, we accomplish this by exploring the chemistry of accreted halo stars from Gaia-Enceladus/Gaia-Sausage (GES) selected in the infrared from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) Data Release 16. We u…
Modelling the water and carbon dioxide production rates of Comet 67P/Churyumov-Gerasimenko
Samarasinha, Nalin H.; Farnocchia, Davide; Gutiérrez, Pedro J. +1 more
The European Space Agency Rosetta/Philae mission to Comet 67P/Churyumov-Gerasimenko in 2014-2016 is the most complete and diverse investigation of a comet carried out thus far. Yet, many physical and chemical properties of the comet remain uncertain or unknown, and cometary activity is still not a well-understood phenomenon. We here attempt to pla…
New LZ and PW(Z) relations of RR Lyrae stars calibrated with Gaia EDR3 parallaxes
Sarro, L. M.; Clementini, G.; Ripepi, V. +4 more
We present new luminosity-metallicity (LZ; $M_{V}\!-\!\rm [Fe/H]$ and $M_{G}\!-\!\rm [Fe/H]$) relations and, for the first time, empirical, Gaia three-band (G, GBP, GRP) period-Wesenheit-metallicity (PWZ) relations of RR Lyrae stars (RRLs) derived using a hierarchical Bayesian approach and new accurate parallaxes published fo…
Birth of a Be star: an APOGEE search for Be stars forming through binary mass transfer
Conroy, Charlie; Stassun, Keivan G.; Cargile, Phillip +7 more
Motivated by recent suggestions that many Be stars form through binary mass transfer, we searched the APOGEE survey for Be stars with bloated, stripped companions. From a well-defined parent sample of 297 Be stars, we identified one mass-transfer binary, HD 15124. The object consists of a main-sequence Be star ($M_{\rm Be}=5.3\pm 0.6\, {\rm M}_{\o…
Study of changes in the pulsation period of 148 Galactic Cepheid variables
Szabados, L.; Cseh, B.; Molnár, L. +7 more
Investigating period changes of classical Cepheids through the framework of O - C diagrams provides a unique insight to the evolution and nature of these variable stars. In this work, the new or extended O - C diagrams for 148 Galactic classical Cepheids are presented. By correlating the calculated period change rates with the Gaia EDR3 colours, w…
Clump survival and migration in VDI galaxies: an analytical model versus simulations and observations
Dekel, Avishai; Primack, Joel; Guo, Yicheng +3 more
We address the nature of the giant clumps in high-z galaxies that undergo violent disc instability, distinguishing between long-lived and short-lived clumps. We study the evolution of long-lived clumps during migration through the disc via an analytical model tested by simulations and confront theory with CANDELS-HST observations. The clump 'batht…
Deep ASKAP EMU Survey of the GAMA23 field: properties of radio sources
Prandoni, I.; Marchetti, L.; Vaccari, M. +19 more
We present the Australian Square Kilometre Array Pathfinder (ASKAP) observations of the Galaxy and Mass Assembly (GAMA)-23h field. The survey was carried out at 887.5 MHz and covers an ~83 square deg field. We imaged the calibrated visibility data, taken as part of the Evolutionary Mapping of Universe Early Science Programme, using the latest vers…
Mira variables in the Milky Way's nuclear stellar disc: discovery and classification
Smith, Leigh C.; Matsunaga, Noriyuki; Minniti, Dante +3 more
The properties of the Milky Way's nuclear stellar disc give crucial information on the epoch of bar formation. Mira variables are promising bright candidates to study the nuclear stellar disc, and through their period-age relation dissect its star formation history. We report on a sample of 1782 Mira variable candidates across the central $3\times…