Search Publications
High-precision chemical abundances of Galactic building blocks. II. Revisiting the chemical distinctness of the Helmi streams
Hattori, Kohei; Helmi, Amina; Ishigaki, Miho N. +6 more
Context. The Helmi streams are a kinematic substructure whose progenitor is likely a dwarf galaxy. Although 20 years have passed since their discovery, it is still unclear whether their members are chemically distinguishable from other halo stars in the Milky Way.
Aims: We aim to precisely characterize the chemical properties of the Helmi str…
Inferring the HII region escape fraction of ionizing photons from infrared emission lines in metal-poor star-forming dwarf galaxies
Morisset, C.; Schaerer, D.; Ramambason, L. +8 more
Local metal-poor galaxies stand as ideal laboratories for probing the properties of the interstellar medium (ISM) in chemically unevolved conditions. Detailed studies of this primitive ISM can help gain insights into the physics of the first primordial galaxies that may be responsible for the reionization. Quantifying the ISM porosity to ionizing …
First light for GRAVITY Wide. Large separation fringe tracking for the Very Large Telescope Interferometer
Lutz, D.; Förster Schreiber, N. M.; Genzel, R. +114 more
GRAVITY+ is the upgrade for GRAVITY and the Very Large Telescope Interferometer (VLTI) with wide-separation fringe tracking, new adaptive optics, and laser guide stars on all four 8 m Unit Telescopes (UTs) to enable ever-fainter, all-sky, high-contrast, milliarcsecond interferometry. Here we present the design and first results of the first phase …
Orbital and dynamical analysis of the system around HR 8799. New astrometric epochs from VLT/SPHERE and LBT/LUCI
Avenhaus, H.; Marzari, F.; Henning, Th. +45 more
Context. HR 8799 is a young planetary system composed of four planets and a double debris belt. Being the first multi-planetary system discovered with the direct imaging technique, it has been observed extensively since 1998. This wide baseline of astrometric measurements, counting over 50 observations in 20 years, permits a detailed orbital and d…
The Close AGN Reference Survey (CARS). No obvious signature of AGN feedback on star formation, but subtle trends
Gaspari, M.; Klessen, R. S.; Combes, F. +17 more
Context. Active galactic nuclei (AGN) are thought to be responsible for the suppression of star formation in massive ∼1010 M⊙ galaxies. While this process is a key feature in numerical simulations of galaxy formation, it has not been unambiguously confirmed in observational studies yet.
Aims: The characterization of the …
Forbidden hugs in pandemic times. III. Observations of the luminous red nova AT 2021biy in the nearby galaxy NGC 4631
Lundqvist, P.; Zheng, W.; Galbany, L. +73 more
We present an observational study of the luminous red nova (LRN) AT 2021biy in the nearby galaxy NGC 4631. The field of the object was routinely imaged during the pre-eruptive stage by synoptic surveys, but the transient was detected only at a few epochs from ∼231 days before maximum brightness. The LRN outburst was monitored with unprecedented ca…
Galaxy cluster strong lensing cosmography. Cosmological constraints from a sample of regular galaxy clusters
Grillo, C.; Rosati, P.; Caminha, G. B. +1 more
Cluster strong lensing cosmography is a promising probe of the background geometry of the Universe and several studies have emerged thanks to the increased quality of observations using space- and ground-based telescopes. For the first time, we used a sample of five cluster strong lenses to measure the values of cosmological parameters and combine…
Asteroseismology of the multiple stellar populations in the globular cluster M4
Milone, A. P.; Tailo, M.; Bragaglia, A. +6 more
We present a new asteroseismic analysis of the stars in the globular cluster (GC) M4 based on the data collected by the K2 mission. We report the detection of solar-like oscillation in 37 stars, 32 red giant branch (RGB) and six red horizontal branch (rHB) stars, which is the largest sample for this kind of study in GCs up to date. Combining infor…
Improved strong lensing modelling of galaxy clusters using the Fundamental Plane: Detailed mapping of the baryonic and dark matter mass distribution of Abell S1063
Grillo, C.; Rosati, P.; Meneghetti, M. +6 more
Aims: From accurate photometric and spectroscopic information, we build the Fundamental Plane (FP) relation for the early-type galaxies of the cluster Abell S1063. We use this relation to develop an improved strong lensing model of the cluster, and we decompose the cluster's cumulative projected total mass profile into its stellar, hot gas, a…
The structure of jets launched from post-AGB binary systems
De Marco, O.; Verhamme, O.; Van Winckel, H. +4 more
Context. In this paper, we focus on post-asymptotic giant branch (post-AGB) binaries and study the interaction between the different components of these complex systems. These components comprise the post-AGB primary, a main sequence secondary, a circumbinary disk, as well as a fast bipolar outflow (jet) launched by the companion. We obtained well…