Related papers: UVMag: stellar formation, evolution, structure and…
We present near ultraviolet imaging with the Hubble Space Telescope Advanced Camera for Surveys, targeting young radio galaxies (Gigahertz Peaked Spectrum and Compact Steep Spectrum sources), in search of star formation regions in their…
The Galaxy Evolution Explorer (GALEX) has performed the first surveys of the sky in the Ultraviolet (UV). Its legacy is an unprecedented database with more than 200 million source measurements in far-UV (FUV) and near-UV (NUV), as well as…
The ``UV upturn'' is a sharp rise in spectra of elliptical galaxies shortward of rest-frame 2500 A. It is a ubiquitous phenomenon in nearby giant elliptical galaxies, and is thought to arise primarily from low-mass evolved stars on the…
The present paper describes the current baseline optical design of POLLUX, a high-resolution spectropolarimeter for the future LUVOIR mission. The instrument will operate in the ultraviolet (UV) domain from 90 to 390 nm in both…
The design and later use of modern spectropolarimeters and magnetographs require a number of tolerance specifications that allow the developers to build the instrument and then the scientists to interpret the data accuracy. Such…
Much of the focus of exoplanet atmosphere analysis in the coming decade will be atinfrared wavelengths, with the planned launches of the James Webb Space Telescope (JWST) and the Wide-Field Infrared Survey Telescope (WFIRST). However,…
The ultraviolet (UV) emission from the most numerous stars in the universe, M dwarfs, impacts the formation, chemistry, atmospheric stability, and surface habitability of their planets. We have analyzed the spectral evolution of UV emission…
Magnetic fields play a fundamental role for interior and atmospheric properties of M dwarfs and greatly influence terrestrial planets orbiting in the habitable zones of these low-mass stars. Determination of the strength and topology of…
The chemical and mass evolution of exoplanet atmospheres is shaped by their specific X-ray through ultraviolet (5 - 3200 Angstroms) irradiance history. X-ray and EUV (5 - 911 Angstroms) radiation largely contributes to atmospheric heating…
The evolution over time of the magnetic activity and the resulting X-ray and UV coronal and chromospheric emissions of main-sequence dG, dK, and dM stars with widely different ages are discussed. Young cool stars spin rapidly and have…
In the coming years, next-generation space-based infrared observatories will significantly increase our samples of rare massive stars, representing a tremendous opportunity to leverage modern statistical tools and methods to test massive…
Observational astrophysics started when spectroscopy could be applied to astronomy. Similarly, observational work on stellar magnetic fields became possible with the application of spectro-polarimetry. In recent decades there have been…
Magnetic fields play important roles in many astrophysical processes. However, there is no universal diagnostic for the magnetic fields in the interstellar medium (ISM) and each magnetic tracer has its limitation. Any new detection method…
We present a comprehensive analysis of the presence of very massive stars (VMS > $100 M_{\odot}$) in the integrated spectra of 13 UV-bright star-forming galaxies at $2.2 \lesssim z \lesssim 3.6$ taken with the Gran Telescopio Canarias…
We report on the status of our spectropolarimetric observations of massive stars. During the last years, we have discovered magnetic fields in many objects of the upper main sequence, including Be stars, beta Cephei and Slowly Pulsating B…
Star clusters are good tracers for formation and evolution of galaxies. We compared different fitting methods by using spectra (or by combining photometry) to determine the physical parameters. We choose a sample of 17 star clusters in M33,…
The 2175 {\AA} bump shows considerable variations in its strength, width, and central wavelength when observed along different sightlines in the Milky Way and other galaxies. These variations offer valuable insights into the composition,…
The structure and dynamics of the outer solar atmosphere are reviewed with emphasis on the role played by the magnetic field. Contemporary observations that focus on high resolution imaging over a range of temperatures, as well as UV, EUV…
Evolved stars are among the primary sources of chemical enrichment and dust production in galaxies. During the giant phases, stars return a substantial fraction of their mass to the interstellar medium (ISM) through stellar winds, enriching…
It is well established in the local Universe that regions of high star-formation rate are dusty. As a result of this physical causal link, galaxies of increasing current star formation activity emit a larger proportion of their bolometric…