Search Publications
The Not So Simple Stellar System ω Cen. II. Evidence in Support of a Merging Scenario
Rest, Armin; Mastrobuono-Battisti, Alessandra; Zenteno, Alfredo +7 more
We present multiband photometry covering ∼5° × 5° across ω Cen collected with the Dark Energy Camera on the 4 m Blanco telescope, combined with Hubble Space Telescope and Wide Field Imager data for the central regions. The unprecedented photometric accuracy and field coverage allows us to confirm the different spatial distribution of blue and red …
A SETI survey of the Vela region using the Murchison Widefield Array: Orders of magnitude expansion in search space
Tremblay, C. D.; Tingay, S. J.
Following the results of our previous low-frequency searches for extraterrestrial intelligence (SETI) using the Murchison Widefield Array (MWA), directed towards the Galactic Centre and the Orion Molecular Cloud (Galactic Anticentre), we report a new large-scale survey towards the Vela region with the lowest upper limits thus far obtained with the…
When Does the Onset of Multiple Stellar Populations in Star Clusters Occur? III. No Evidence of Significant Chemical Variations in Main-sequence Stars of NGC 419
Milone, Antonino P.; Li, Chengyuan; Ji, Xin +3 more
Recent studies have revealed that the onset age for the presence of multiple stellar populations (MPs) in star clusters seems to correspond to the disappearance of the extended main-sequence turnoff in young clusters, a pattern associated with stellar rotations. A speculative suggestion is that MPs might be caused by the magnetic brake, a stellar …
Diffuse radio emission in the galaxy cluster SPT-CL J2031-4037: a steep-spectrum intermediate radio halo?
van Weeren, R. J.; Rapetti, David; Intema, H. T. +6 more
The advent of sensitive low-frequency radio observations has revealed a number of diffuse radio objects with peculiar properties that are challenging our understanding of the physics of the intracluster medium. Here, we report the discovery of a steep-spectrum radio halo surrounding the central brightest cluster galaxy (BCG) in the galaxy cluster …
Rotation of Solar Analogs Crossmatching Kepler and Gaia DR2
Barnes, S. A.; Castro, M.; da Costa, J. S. +10 more
A major obstacle to interpreting the rotation period distribution for main-sequence stars from Kepler mission data has been the lack of a precise evolutionary status for these objects. We address this by investigating the evolutionary status based on Gaia Data Release 2 parallaxes and photometry for more than 30,000 Kepler stars with rotation peri…
Correlations of Sunspot Physical Characteristics during Solar Cycle 23
Valio, Adriana; Spagiari, Eduardo; Marengoni, Mauricio +1 more
The behavior of sunspots is governed by the magnetic dynamo acting deep within the convection zone of the Sun. Therefore, knowledge of sunspot physical characteristics and how they evolve in time during a solar cycle can help to improve our understanding of the solar magnetic behavior. This work analyzes the physical characteristics of sunspots du…
HD 150382: A Lithium-rich Star at the Early-AGB Stage?
Pereira, C. B.; Holanda, N.; Drake, N. A.
We report the discovery of a lithium-rich giant, HD 150382, a post-red-giant-branch clump star. The atmospheric parameters, the chemical abundances for 17 elements, and the isotopic ratio 12C/13C were determined using the equivalent width and the spectral synthesis methods. The lithium abundance was determined via spectral sy…
Lyman continuum leakage in faint star-forming galaxies at redshift z = 3-3.5 probed by gamma-ray bursts
Covino, S.; Campana, S.; Salvaterra, R. +23 more
Context. The identification of the sources that reionized the Universe and their specific contribution to this process are key missing pieces of our knowledge of the early Universe. Faint star-forming galaxies may be the main contributors to the ionizing photon budget during the epoch of reionization, but their escaping photons cannot be detected …
The chemical composition of impact craters on Titan. I. Implications for exogenic processing
Drossart, P.; Witasse, O.; Altobelli, N. +12 more
We investigate the spectral behavior of nine Titan impact craters in order to constrain their composition. Past studies that have examined the chemical composition of impact craters on Titan have either used qualitative comparisons between craters or combined all craters into a single unit, rather than separating them by geographic location and/or…
CO-driven activity constrains the origin of comets
Blum, J.; Fulle, M.; Rotundi, A.
Context. An open question in the study of comets is the so-called cohesion bottleneck, that is, how dust particles detach from the nucleus.
Aims: We test whether the CO pressure buildup inside the pebbles of which cometary nuclei consist can overcome this cohesion bottleneck.
Methods: A recently developed pebble-diffusion model was appli…