Related papers: Trimming Down the Willman 1 dSph

The Milky Way Bulge extra-tidal star survey (MWBest) is a spectroscopic survey with the goal of identifying stripped globular cluster stars from inner Galaxy clusters. In this way, an indication of the fraction of metal-poor bulge stars…

The Milky Way satellite dwarf spheroidal (dSph) galaxies are the smallest dark matter dominated systems in the universe. We have underway dynamical studies of the dSph to quantify the shortest scale lengths on which Dark Matter is…

Planet frequency shows a strong positive correlation with host mass from the hydrogen-burning limit to M ~ 2Msun. No search has yet been conducted for planets of higher-mass hosts because all existing techniques are insensitive to these…

We report the discovery of a spectroscopically-confirmed strong Lyman-$\alpha$ emitter at $z=7.0281\pm0.0003$, observed as part of the Reionization Cluster Lensing Survey (RELICS). This galaxy, dubbed "Dichromatic Primeval Galaxy" at…

For the first time accurate pulsation properties of the ancient variable stars of the Fornax dwarf spheroidal galaxy (dSph) are discussed in the broad context of galaxy formation and evolution. Homogeneous multi-band $BVI$ optical…

A reduced proper motion diagram utilizing Sloan Digital Sky Survey (SDSS) photometry and astrometry and USNO-B plate astrometry is used to separate cool white dwarf candidates from metal-weak, high-velocity main sequence Population II stars…

We present a sample of 45 Damped Lyman-$\alpha$ system (DLA, \nhi\ $ \geq 2 \times 10^{20} {\rm cm}^{-2}$) counterparts (33 detections, 12 upper limits) which host gamma-ray bursts (GRB-DLAs) in order to investigate star-formation and…

A review of observational evidence in favour of a metallicity dependence of WN and WC stars is presented. New near-IR studies of Milky Way, LMC and SMC early-type WN stars are presented, with weake winds amongst WN stars containing…

We present the discovery of an exceptional dimming event in a cool supergiant star in the Local Volume spiral M51. The star, dubbed M51-DS1, was found as part of a Hubble Space Telescope (HST) search for failed supernovae (SNe). The…

We present a sample of 148 candidate RR Lyrae stars selected from Sloan Digital Sky Survey (SDSS) commissioning data for about 100 deg2 of sky surveyed twice with Delta(t) = 1.9946 days. Although the faint magnitude limit of the SDSS allows…

We present results from the analysis of the optical spectra of 47 radio-selected narrow-line Seyfert 1 galaxies (NLS1s). These objects are a subset of the First Bright Quasar Survey (FBQS) and were initially detected at 20 cm (flux density…

We present a new catalog of narrow-line Seyfert 1 (NLSy1) galaxies from the Sloan Digital Sky Survey Data Release 12 (SDSS DR12). This was obtained by a systematic analysis through modeling of the continuum and emission lines of the spectra…

We present Lick Observatory slit spectra of 38 objects which were claimed to have pronounced ultraviolet excess and emission lines by Zhan \& Chen. Most of our spectra have FWHM spectral resolutions of about 4~\AA , and relatively high S/N…

We show that Milky Way white dwarfs are excellent targets for dark matter (DM) detection. Using Fermi and H.E.S.S. Galactic center gamma-ray data, we investigate sensitivity to DM annihilating within white dwarfs into long-lived or boosted…

The atmospheres of very cool, hydrogen-rich white dwarfs (Teff <6000 K) are challenging to models because of the increased complexity of the equation of state, chemical equilibrium, and opacity sources in a low-temperature, weakly ionized…

High resolution spectra of 34 halo population dwarf and subgiant stars have been obtained with VLT/UVES and used to derive sulphur abundances from the 8694.0, 8694.6 A and 9212.9, 9237.5 A SI lines. In addition, iron abundances have been…

As part of a program to measure abundance ratios in stars beyond 15 kpc from the Galactic center, we have discovered a metal-poor star in the outer halo with a unique chemical signature. We originally identified it in the Sloan Extension…

In this work, we extend the catalog of low-surface brightness (LSB) galaxies, including Ultra-Diffuse Galaxy (UDG) candidates, within $\approx 0.4R_{vir}$ of the Hydra I cluster of galaxies, based on deep images from the VST Early-type…

We describe the search for Lyman-break galaxies (LBGs) near the sub-millimeter bright starburst galaxy HFLS3 at $z$$=$6.34 and a study on the environment of this massive galaxy during the end of reionization.We performed two independent…

We present 16 new ultrabright $H_{AB}\lesssim25$ galaxy candidates at z~8 identified over the COSMOS/UltraVISTA field. The new search takes advantage of the deepest-available ground-based optical and near-infrared observations, including…