Search Publications
Cepheids as distance indicators and stellar tracers
Bono, G.; Pietrinferni, A.; Braga, V. F.
We review the phenomenology of classical Cepheids (CCs), Anomalous Cepheids (ACs) and type II Cepheids (TIICs) in the Milky Way (MW) and in the Magellanic Clouds (MCs). We also examine the Hertzsprung progression in different stellar systems by using the shape of I-band light curves (Fourier parameters) and observables based on the difference in m…
Stellar occultations by trans-Neptunian objects
Sicardy, Bruno; Buie, Marc W.; Braga-Ribas, Felipe +2 more
Stellar occultations provide a powerful tool to explore objects of the outer solar system. The Gaia mission now provides milli-arcsec accuracy on the predictions of these events and makes possible observations that were previously unthinkable. Occultations return kilometric accuracies on the three-dimensional shape of bodies irrespective of their …
Cosmic ray feedback in galaxies and galaxy clusters
Pfrommer, Christoph; Ruszkowski, Mateusz
Understanding the physical mechanisms that control galaxy formation is a fundamental challenge in contemporary astrophysics. Recent advances in the field of astrophysical feedback strongly suggest that cosmic rays (CRs) may be crucially important for our understanding of cosmological galaxy formation and evolution. The appealing features of CRs ar…
Dynamics and clouds in planetary atmospheres from telescopic observations
Sánchez-Lavega, Agustín; Irwin, Patrick; García Muñoz, Antonio
This review presents an insight into our current knowledge of the atmospheres of the planets Venus, Mars, Jupiter, Saturn, Uranus and Neptune, the satellite Titan, and those of exoplanets. It deals with the thermal structure, aerosol properties (hazes and clouds, dust in the case of Mars), chemical composition, global winds, and selected dynamical…
Fast radio bursts at the dawn of the 2020s
Lorimer, D. R.; Hessels, J. W. T.; Petroff, E.
Since the discovery of the first fast radio burst (FRB) in 2007, and their confirmation as an abundant extragalactic population in 2013, the study of these sources has expanded at an incredible rate. In our 2019 review on the subject, we presented a growing, but still mysterious, population of FRBs—60 unique sources, 2 repeating FRBs, and only 1 i…
Ram pressure stripping in high-density environments
Fossati, Matteo; Sun, Ming; Boselli, Alessandro
Galaxies living in rich environments are suffering different perturbations able to drastically affect their evolution. Among these, ram pressure stripping, i.e. the pressure exerted by the hot and dense intracluster medium (ICM) on galaxies moving at high velocity within the cluster gravitational potential well, is a key process able to remove the…
The evolution of CNO elements in galaxies
Romano, Donatella
After hydrogen and helium, oxygen, carbon, and nitrogen—hereinafter, the CNO elements—are the most abundant species in the universe. They are observed in all kinds of astrophysical environments, from the smallest to the largest scales, and are at the basis of all known forms of life, hence, the constituents of any biomarker. As such, their study p…
Low-energy cosmic rays: regulators of the dense interstellar medium
Gabici, Stefano
Low-energy cosmic rays (up to the GeV energy domain) play a crucial role in the physics and chemistry of the densest phase of the interstellar medium. Unlike interstellar ionising radiation, they can penetrate large column densities of gas, and reach molecular cloud cores. By maintaining there a small but not negligible gas ionisation fraction, th…
Compact steep-spectrum and peaked-spectrum radio sources
O'Dea, Christopher P.; Saikia, D. J.
Compact steep-spectrum (CSS) and peaked-spectrum (PS) radio sources are compact, powerful radio sources. The multi-frequency observational properties and current theories are reviewed with emphasis on developments since the earlier review of O'Dea (PASP 110:493-532, https://doi.org/10.1086/316162, 1998). There are three main hypotheses for the nat…
A buyer's guide to the Hubble constant
Lahav, Ofer; Lemos, Pablo; Shah, Paul
Since the expansion of the universe was first established by Edwin Hubble and Georges Lemaître about a century ago, the Hubble constant H0 which measures its rate has been of great interest to astronomers. Besides being interesting in its own right, few properties of the universe can be deduced without it. In the last decade, a signific…