Search Publications

The Milky Way's stellar streams and globular clusters do not align in a Vast Polar Structure
DOI: 10.1093/mnras/staa710 Bibcode: 2020MNRAS.494..983R

Riley, Alexander H.; Strigari, Louis E.

There is increasing evidence that a substantial fraction of Milky Way satellite galaxies align in a rotationally supported plane of satellites, a rare configuration in cosmological simulations of galaxy formation. It has been suggested that other Milky Way substructures (namely young halo globular clusters and stellar/gaseous streams) similarly te…

2020 Monthly Notices of the Royal Astronomical Society
Gaia 33
Cosmological Insights into the Early Accretion of r-process-enhanced Stars. I. A Comprehensive Chemodynamical Analysis of LAMOST J1109+0754
DOI: 10.3847/1538-4357/abbc13 Bibcode: 2020ApJ...903...88M

Zhao, Gang; Beers, Timothy C.; Placco, Vinicius M. +11 more

This study presents a comprehensive chemodynamical analysis of LAMOST J1109+0754, a bright (V = 12.8), extremely metal-poor ([Fe/H] = -3.17) star, with a strong r-process enhancement ([Eu/Fe] = +0.94 ± 0.12). Our results are based on the 7D measurements supplied by Gaia and the chemical composition derived from a high-resolution (R ∼ 110,000), hig…

2020 The Astrophysical Journal
Gaia 33
Effective J -factors for Milky Way dwarf spheroidal galaxies with velocity-dependent annihilation
DOI: 10.1103/PhysRevD.102.023029 Bibcode: 2020PhRvD.102b3029B

Pace, Andrew B.; Kumar, Jason; Runburg, Jack +2 more

We calculate the effective J -factors, which determine the strength of indirect detection signals from dark matter annihilation, for 25 dwarf spheroidal galaxies (dSphs). We consider several well-motivated assumptions for the relative velocity dependence of the dark matter annihilation cross section: σAv : s -wave (velocity independent)…

2020 Physical Review D
Gaia 32
NGC 4993, the shell galaxy host of GW170817: constraints on the recent galactic merger
DOI: 10.1051/0004-6361/201935219 Bibcode: 2020A&A...634A..73E

Ebrová, I.; Bílek, M.; Yıldız, M. K. +1 more

Context. NGC 4993 is the shell galaxy host of the GRB170817A short gamma-ray burst and the GW170817 gravitational-wave event produced during a binary-neutron-star coalescence.
Aims: The galaxy shows signs, including the stellar shells, that it has recently accreted a smaller, late-type galaxy. The accreted galaxy might be the original host of…

2020 Astronomy and Astrophysics
eHST 32
Testing dark energy models with a new sample of strong-lensing systems
DOI: 10.1093/mnras/staa2760 Bibcode: 2020MNRAS.498.6013A

Motta, V.; Amante, Mario H.; García-Aspeitia, Miguel A. +2 more

Inspired by a new compilation of strong-lensing systems, which consist of 204 points in the redshift range 0.0625 < zl < 0.958 for the lens and 0.196 < zs < 3.595 for the source, we constrain three models that generate a late cosmic acceleration: the ω-cold dark matter model, the Chevallier-Polarski-Linder, and th…

2020 Monthly Notices of the Royal Astronomical Society
eHST 32
Photometry and performance of SPECULOOS-South
DOI: 10.1093/mnras/staa1283 Bibcode: 2020MNRAS.495.2446M

Queloz, D.; Delrez, L.; Gillon, M. +16 more

SPECULOOS-South, an observatory composed of four independent 1-m robotic telescopes, located at ESO Paranal, Chile, started scientific operation in 2019 January. This Southern hemisphere facility operates as part of the Search for Habitable Planets EClipsing ULtra-cOOl Stars (SPECULOOS), an international network of 1-m-class telescopes surveying f…

2020 Monthly Notices of the Royal Astronomical Society
Gaia 32
Magnetic field turbulence in the solar wind at sub-ion scales: in situ observations and numerical simulations
DOI: 10.3389/fspas.2020.563075 Bibcode: 2020FrASS...7...83M

Hellinger, P.; Alexandrova, O.; Matteini, L. +5 more

We investigate the transition of the solar wind turbulent cascade from MHD to sub-ion range by means of a detail comparison between in situ observations and hybrid numerical simulations. In particular we focus on the properties of the magnetic field and its component anisotropy in Cluster measurements and hybrid 2D simulations. First, we address t…

2020 Frontiers in Astronomy and Space Sciences
Cluster 32
The Luminosity Function of Red Supergiants in M31
DOI: 10.3847/1538-4357/ab5ba0 Bibcode: 2020ApJ...889...44N

Drout, Maria R.; Massey, Philip; Levesque, Emily M. +5 more

The mass-loss rates of red supergiant stars (RSGs) are poorly constrained by direct measurements, and yet the subsequent evolution of these stars depends critically on how much mass is lost during the RSG phase. In 2012 the Geneva evolutionary group updated their mass-loss prescription for RSGs with the result that a 20 M star now lose…

2020 The Astrophysical Journal
Gaia 32
X-ray properties of z ≳ 6.5 quasars
DOI: 10.1093/mnras/stz3275 Bibcode: 2020MNRAS.491.3884P

Banerji, M.; McMahon, R. G.; Pons, E. +1 more

We present XMM-Newton X-ray observations and analysis of three Dark Energy Survey z > 6.5 quasars (VDES J0020-3653 at z = 6.824, VDES J0244-5008 at z = 6.724, and VDES J0224-4711 at z = 6.526) and six other quasars with 6.438 < z < 6.747 from the XMM-Newton public archive. Two of the nine quasars are detected at a high (>4σ) significan…

2020 Monthly Notices of the Royal Astronomical Society
XMM-Newton 32
Search for Nearby Earth Analogs. II. Detection of Five New Planets, Eight Planet Candidates, and Confirmation of Three Planets around Nine Nearby M Dwarfs
DOI: 10.3847/1538-4365/ab5e7c Bibcode: 2020ApJS..246...11F

Butler, R. Paul; Crane, Jeffrey D.; Thompson, Ian B. +9 more

Zechmeister et al. surveyed 38 nearby M dwarfs from 2000 to 2007 March with VLT2 and the Ultraviolet and Visual Echelle Spectrograph (UVES) spectrometer. These data have recently been reanalyzed, yielding a significant improvement in the Doppler velocity precision. Spurred by this, we have combined the UVES data with velocity sets from High Accura…

2020 The Astrophysical Journal Supplement Series
Gaia 32