Search Publications
Solar Ultraviolet Bursts
Chitta, L. P.; Heinzel, Petr; Toriumi, Shin +16 more
The term "ultraviolet (UV) burst" is introduced to describe small, intense, transient brightenings in ultraviolet images of solar active regions. We inventorize their properties and provide a definition based on image sequences in transition-region lines. Coronal signatures are rare, and most bursts are associated with small-scale, canceling oppos…
The First Naked-eye Superflare Detected from Proxima Centauri
Loyd, R. O. Parke; Law, Nicholas M.; Youngblood, Allison +11 more
Proxima b is a terrestrial-mass planet in the habitable zone of Proxima Centauri. Proxima Centauri’s high stellar activity, however, casts doubt on the habitability of Proxima b: sufficiently bright and frequent flares and any associated proton events may destroy the planet’s ozone layer, allowing lethal levels of UV flux to reach its surface. In …
Intracluster light at the Frontier - II. The Frontier Fields Clusters
Trujillo, Ignacio; Montes, Mireia
Multiwavelength deep observations are a key tool to understand the origin of the diffuse light in clusters of galaxies: the intracluster light (ICL). For this reason, we take advantage of the Hubble Frontier Fields (HFF) survey to investigate the properties of the stellar populations of the ICL of its six massive intermediate redshift (0.3 < z …
Metal-enriched galactic outflows shape the mass-metallicity relationship
Chisholm, J.; Leitherer, C.; Tremonti, C.
The gas-phase metallicity of low-mass galaxies increases with increasing stellar mass (M*) and is nearly constant for high-mass galaxies. Theory suggests that this tight mass-metallicity relationship is shaped by galactic outflows removing metal-enriched gas from galaxies. Here, we observationally model the outflow metallicities of the …
Multiple stellar populations in Magellanic Cloud clusters - VI. A survey of multiple sequences and Be stars in young clusters
Di Criscienzo, M.; Anderson, J.; Milone, A. P. +16 more
The split main sequences (MSs) and extended MS turnoffs (eMSTOs) detected in a few young clusters have demonstrated that these stellar systems host multiple populations differing in a number of properties such as rotation and, possibly, age. We analyse Hubble Space Telescope photometry for 13 clusters with ages between ∼40 and ∼1000 Myr and of dif…
The Galactic warp revealed by Gaia DR2 kinematics
Bailer-Jones, C. A. L.; Fouesneau, M.; Andrae, R. +14 more
Using Gaia DR2 astrometry, we map the kinematic signature of the Galactic stellar warp out to a distance of 7 kpc from the Sun. Combining Gaia DR2 and 2-Micron All Sky Survey photometry, we identify, via a probabilistic approach, 599 494 upper main sequence (UMS) stars and 12 616 068 giants without the need for individual extinction estimates. The…
Neutrino masses and their ordering: global data, priors and models
de Salas, P. F.; Gariazzo, S.; Archidiacono, M. +3 more
We present a full Bayesian analysis of the combination of current neutrino oscillation, neutrinoless double beta decay and Cosmic Microwave Background observations. Our major goal is to carefully investigate the possibility to single out one neutrino mass ordering, namely Normal Ordering or Inverted Ordering, with current data. Two possible parame…
An overabundance of black hole X-ray binaries in the Galactic Centre from tidal captures
Metzger, B. D.; Generozov, A.; Stone, N. C. +1 more
A large population of X-ray binaries (XRBs) was recently discovered within the central parsec of the Galaxy by Hailey et al. While the presence of compact objects on this scale due to radial mass segregation is, in itself, unsurprising, the fraction of binaries would naively be expected to be small because of how easily primordial binaries are dis…
The nature of giant clumps in distant galaxies probed by the anatomy of the cosmic snake
Pérez-González, Pablo G.; Richard, Johan; Schaerer, Daniel +4 more
Giant stellar clumps are ubiquitous in high-redshift galaxies1,2. They are thought to play an important role in the build-up of galactic bulges3 and as diagnostics of star formation feedback in galactic discs4. Hubble Space Telescope (HST) blank field imaging surveys have estimated that these clumps have masses of …
Large-scale stability and astronomical constraints for coupled dark-energy models
Yang, Weiqiang; Pan, Supriya; Barrow, John D.
We study large-scale inhomogeneous perturbations and instabilities of interacting dark-energy models. Past analysis of large-scale perturbative instabilities has shown that we can only test interacting dark-energy models with observational data when their parameter ranges are either wx≥-1 and ξ ≥0 , or wx≤-1 and ξ ≤0 , where …