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The fourth data release of the Kilo-Degree Survey: ugri imaging and nine-band optical-IR photometry over 1000 square degrees
DOI: 10.1051/0004-6361/201834918 Bibcode: 2019A&A...625A...2K

Sutherland, W.; Heymans, C.; Hoekstra, H. +20 more

Context. The Kilo-Degree Survey (KiDS) is an ongoing optical wide-field imaging survey with the OmegaCAM camera at the VLT Survey Telescope, specifically designed for measuring weak gravitational lensing by galaxies and large-scale structure. When completed it will consist of 1350 square degrees imaged in four filters (ugri).
Aims: Here we pr…

2019 Astronomy and Astrophysics
Gaia 299
Kinematics in Young Star Clusters and Associations with Gaia DR2
DOI: 10.3847/1538-4357/aaef8c Bibcode: 2019ApJ...870...32K

Sills, Alison; Feigelson, Eric D.; Hillenbrand, Lynne A. +2 more

The Gaia mission has opened a new window into the internal kinematics of young star clusters at the sub-km s-1 level, with implications for our understanding of how star clusters form and evolve. We use a sample of 28 clusters and associations with ages from ∼1-5 Myr, where lists of members are available from previous X-ray, optical, an…

2019 The Astrophysical Journal
Gaia eHST 296
How to Constrain Your M Dwarf. II. The Mass-Luminosity-Metallicity Relation from 0.075 to 0.70 Solar Masses
DOI: 10.3847/1538-4357/aaf3bc Bibcode: 2019ApJ...871...63M

Gaidos, Eric; Rizzuto, Aaron C.; Kraus, Adam L. +11 more

The mass-luminosity relation for late-type stars has long been a critical tool for estimating stellar masses. However, there is growing need for both a higher-precision relation and a better understanding of systematic effects (e.g., metallicity). Here we present an empirical relationship between {M}{KS} and M * sp…

2019 The Astrophysical Journal
Gaia eHST 291
Exoplanetary Atmospheres: Key Insights, Challenges, and Prospects
DOI: 10.1146/annurev-astro-081817-051846 Bibcode: 2019ARA&A..57..617M

Madhusudhan, Nikku

Exoplanetary science is on the verge of an unprecedented revolution. The thousands of exoplanets discovered over the past decade have most recently been supplemented by discoveries of potentially habitable planets around nearby low-mass stars. Currently, the field is rapidly progressing toward detailed spectroscopic observations to characterize th…

2019 Annual Review of Astronomy and Astrophysics
eHST 284
An Improved Distance to NGC 4258 and Its Implications for the Hubble Constant
DOI: 10.3847/2041-8213/ab552d Bibcode: 2019ApJ...886L..27R

Riess, A. G.; Reid, M. J.; Pesce, D. W.

NGC 4258 is a critical galaxy for establishing the extragalactic distance scale and estimating the Hubble constant ({H}0). Water masers in the nucleus of the galaxy orbit about its supermassive black hole, and very long baseline interferometric observations of their positions, velocities, and accelerations can be modeled to give a geome…

2019 The Astrophysical Journal
eHST 273
A noninteracting low-mass black hole-giant star binary system
DOI: 10.1126/science.aau4005 Bibcode: 2019Sci...366..637T

Bieryla, Allyson; Latham, David W.; Berlind, Perry +14 more

Black hole binary systems with companion stars are typically found via their x-ray emission, generated by interaction and accretion. Noninteracting binaries are expected to be plentiful in the Galaxy but must be observed using other methods. We combine radial velocity and photometric variability data to show that the bright, rapidly rotating giant…

2019 Science
Gaia 265
Water Vapor and Clouds on the Habitable-zone Sub-Neptune Exoplanet K2-18b
DOI: 10.3847/2041-8213/ab59dc Bibcode: 2019ApJ...887L..14B

Fortney, Jonathan J.; Knutson, Heather A.; Howard, Andrew W. +13 more

Results from the Kepler mission indicate that the occurrence rate of small planets (<3 R ) in the habitable zone of nearby low-mass stars may be as high as 80%. Despite this abundance, probing the conditions and atmospheric properties on any habitable-zone planet is extremely difficult and has remained elusive to date. Here, we repo…

2019 The Astrophysical Journal
Gaia eHST 262
Primordial Black Holes as a Dark Matter Candidate Are Severely Constrained by the Galactic Center 511 keV γ -Ray Line
DOI: 10.1103/PhysRevLett.123.251101 Bibcode: 2019PhRvL.123y1101L

Laha, Ranjan

We derive the strongest constraint on the fraction of dark matter that can be composed of low mass primordial black holes by using the observation of the Galactic Center 511 keV γ -ray line. Primordial black holes of masses ≲1015 kg will evaporate to produce e± pairs. The positrons will lose energy in the Galactic Center, bec…

2019 Physical Review Letters
INTEGRAL 256
The origin of accreted stellar halo populations in the Milky Way using APOGEE, Gaia, and the EAGLE simulations
DOI: 10.1093/mnras/sty2955 Bibcode: 2019MNRAS.482.3426M

Bovy, Jo; Majewski, Steven R.; Holtzman, Jon +12 more

Recent work indicates that the nearby Galactic halo is dominated by the debris from a major accretion event. We confirm that result from an analysis of APOGEE-DR14 element abundances and Gaia-DR2 kinematics of halo stars. We show that ∼2/3 of nearby halo stars have high orbital eccentricities (e ≳ 0.8), and abundance patterns typical of massive Mi…

2019 Monthly Notices of the Royal Astronomical Society
Gaia 255
juliet: a versatile modelling tool for transiting and non-transiting exoplanetary systems
DOI: 10.1093/mnras/stz2688 Bibcode: 2019MNRAS.490.2262E

Espinoza, Néstor; Kossakowski, Diana; Brahm, Rafael

Here we present juliet, a versatile tool for the analysis of transits, radial velocities, or both. juliet is built over many available tools for the modelling of transits, radial velocities, and stochastic processes (here modelled as Gaussian Processes; GPs) in order to deliver a tool/wrapper which can be used for the analysis of transit photometr…

2019 Monthly Notices of the Royal Astronomical Society
Gaia 252