Search Publications
TDCOSMO: XVI. Measurement of the Hubble constant from the lensed quasar WGD 2038–4008
Treu, Tommaso; Marshall, Philip J.; Fassnacht, Christopher D. +17 more
Time-delay cosmography is a powerful technique to constrain cosmological parameters, particularly the Hubble constant (H0). The TDCOSMO Collaboration is performing an ongoing analysis of lensed quasars to constrain cosmology using this method. In this work, we obtain constraints from the lensed quasar WGD 2038‑4008 using new time-delay …
Combined Gemini-South and HST photometric analysis of the globular cluster NGC 6558: The age of the metal-poor population of the Galactic bulge
Bica, E.; Nardiello, D.; Barbuy, B. +8 more
Context. NGC 6558 is a low-galactic-latitude globular cluster projected in the direction of the Galactic bulge. Due to high reddening, this region presents challenges in deriving accurate parameters, which require meticulous photometric analysis. We present a combined analysis of near-infrared and optical photometry from multi-epoch high-resolutio…
From gas to stars: MUSEings on the internal evolution of IC 1613
Iorio, G.; Kacharov, N.; Skillman, E. D. +9 more
Context. The kinematics and chemical composition of stellar populations of different ages provide crucial information on the evolution of the various components of a galaxy. Aim. Our aim is to determine the kinematics of individual stars as a function of age in IC 1613, a star-forming, gas-rich, and isolated dwarf galaxy of the Local Group (LG). M…
Cepheid Metallicity in the Leavitt Law (C-MetaLL) survey: VI. Radial abundance gradients of 29 chemical species in the Milky Way disc
Ripepi, V.; Molinaro, R.; Marconi, M. +9 more
Context. Classical Cepheids (DCEPs) are crucial for calibrating the extragalactic distance ladder, ultimately enabling the determination of the Hubble constant through the period-luminosity (PL) and period-Wesenheit (PW) relations that they exhibit. Hence, it is vital to understand how the PL and PW relations depend on metallicity. This is the pur…
The original composition of the gas forming first-generation stars in clusters: Insights from HST and JWST
Milone, A. P.; Cordoni, G.; Marino, A. F. +8 more
Globular cluster (GC) stars composed of pristine material, also known as first-generation (1G) stars, are not chemically homogeneous as they exhibit extended sequences in the chromosome map (ChM). Recent studies characterized 1G stars within the center of 55 Galactic GCs, revealing metallicity variations. Despite this progress, several unanswered …
The spin, expansion, and contraction of open star clusters
Jadhav, Vikrant V.; Kroupa, Pavel; Thies, Ingo +2 more
Context. Empirical constraints on the internal dynamics of open clusters are important for understanding their evolution and evaporation. High-precision astrometry from Gaia DR3 is thus useful to observe aspects of the cluster dynamics.
Aims: This work aims to identify dynamically peculiar clusters such as spinning and expanding clusters. We …
Improved model of the Supernova Refsdal cluster MACS J1149.5+2223 thanks to VLT/MUSE
Grillo, C.; Rosati, P.; Stiavelli, M. +9 more
We present new VLT/MUSE observations of the Hubble Frontier Field (HFF) galaxy cluster MACS J1149.5+2223, lensing the well-known supernova "Refsdal" into multiple images, which has enabled the first cosmological applications with a strongly lensed supernova. Thanks to these data, targeting a northern region of the cluster and thus complementing ou…
At the end of cosmic noon: Short gas depletion times in unobscured quasars at z ∼ 1
Rybak, M.; McKean, J. P.; van der Werf, P. +8 more
Unobscured quasars (QSOs) are predicted to be the final stage in the evolutionary sequence from gas-rich mergers to gas-depleted, quenched galaxies. Studies of this population, however, find a high incidence of far-infrared-luminous sources-suggesting significant dust-obscured star formation-but direct observations of the cold molecular gas fuelli…
The tidal deformation and atmosphere of WASP-12 b from its phase curve★
Alonso, R.; Deleuil, M.; Erikson, A. +85 more
Context. Ultra-hot Jupiters present a unique opportunity to understand the physics and chemistry of planets, their atmospheres, and interiors at extreme conditions. WASP-12 b stands out as an archetype of this class of exoplanets, with a close-in orbit around its star that results in intense stellar irradiation and tidal effects.
Aims: The go…
Hypervelocity star candidates from Gaia DR2 and DR3 proper motions and parallaxes
Scholz, R. -D.
Context. Hypervelocity stars (HVSs) unbound to the Galaxy can be formed with extreme stellar interactions, for example close encounters with supermassive black holes or in massive star clusters, supernova explosions in binary systems, or the stripping of dwarf galaxies. Observational evidence comes from measurements of radial velocities (RVs) of o…