Related papers: A Study of Stochastic Low-Frequency Variability fo…
Mass-loss from massive stars is fundamental to stellar and galactic evolution and enrichment of the interstellar medium. Reliable determination of mass-loss rate is dependent upon unravelling details of massive star outflows, including…
High-precision photometric observations have revealed ubiquitous stochastic low-frequency photometric variability in early type stars. It has been suggested that this variability arises due to either subsurface convection or internal…
Radio emission is a key indicator of star-formation activity in galaxies, but the radio luminosity-star formation relation has to date been studied almost exclusively at frequencies of 1.4 GHz or above. At lower radio frequencies the…
We measure star-formation rates (SFRs) and specific SFRs (SSFRs) of Ks-selected galaxies from the VIDEO survey by stacking 1.4-GHz Very Large Array data. We split the sample, which spans 0 < z < 3 and stellar masses 10**8.0 < Mstellar/Msol…
Line-driven wind instability is expected to cause small-scale wind inhomogeneities, X-ray emission, and wind line profile variability. The instability can already develop around the sonic point if it is initiated close to the photosphere…
Extragalactic studies have demonstrated there is a moderately tight ($\approx$0.3 dex) relationship between galaxy stellar mass ($M_{\star}$) and star formation rate (SFR) that holds for star-forming galaxies at $M_{\star} \sim 3 \times…
The broad-band radio spectral energy distribution (SED) of star-forming galaxies (SFGs) contains a wealth of complex physics. We aim to determine the physical emission and loss processes causing radio SED curvature and steepening to see…
We constrain the slope of the star formation rate ($\log\Psi$) to stellar mass ($\log\mathrm{M_{\star}}$) relation down to $\log(\mathrm{M_{\star}/M_{\odot}})=8.4$ ($\log(\mathrm{M_{\star}/M_{\odot}})=9.2$) at $z=0.5$ ($z=2.5$) with a…
Uncertainties in stellar structure and evolution theory are largest for stars undergoing core convection on the main sequence. A powerful way to calibrate the free parameters used in the theory of stellar interiors is asteroseismology,…
Rotation is of key importance for the evolution of hot massive stars, however, the rotational velocities of these stars are difficult to determine. Based on our own data for 31 Galactic O stars and incorporating similar data for 86 OB…
Massive stars show a variety of spectral variability: presence of discrete absorption components in UV P-Cygni profiles, optical line profile variability, X-ray variability, radial velocity modulations. Our goal is to study the spectral…
We present a variability study of 4646 massive stars in the Small Magellanic Cloud (SMC) with known spectral types from the catalog of Bonanos et al. (2010) using the light curves from the OGLE-III database. The goal is to exploit the time…
Analysis of late O-type stars observed in the Large Magellanic Cloud (LMC) by the VLT-FLAMES Tarantula Survey (VFTS) revealed a discrepancy between the physical properties estimated from model-atmosphere analysis and those expected from…
We use the UV-optical color magnitude diagram in combination with spectroscopic and photometric measurements derived from the SDSS spectroscopic sample to measure the distribution of galaxies in the local universe (z<0.25) and their…
The Star formation rate (SFR) is a crucial parameter to investigate galaxy evolution. At low redshift the cosmic SFR density declines smoothly, and massive active galaxies become passive, reducing their star formation activity. This implies…
Massive stars play a key role in the evolution of the Universe. Our goal is to compare observed and predicted properties of single Galactic O stars to identify and constrain uncertain physical parameters and processes in stellar evolution…
Massive stars likely played an important role in the reionization of the Universe, and the formation of the first black holes. Massive stars in low-metallicity environments in the local Universe are reminiscent of their high redshift…
Stars exhibit a bewildering variety of variable behaviors ranging from explosive magnetic flares to stochastically changing accretion to periodic pulsations or rotations. The principal LSST surveys will have cadences too sparse and…
Stars exhibit a bewildering variety of rapidly variable behaviors ranging from explosive magnetic flares to stochastically changing accretion to periodic pulsations or rotation. The principal Rubin Observatory Legacy Survey of Space and…
We present a demographic analysis of integrated star formation and gas properties for a sample of galaxies representative of the overall population at z~0. This research was undertaken in order to characterise the nature of star formation…