Search Publications
Gas phase Elemental abundances in Molecular cloudS (GEMS). I. The prototypical dark cloud TMC 1
Roueff, E.; Kirk, J.; Ward-Thompson, D. +30 more
GEMS is an IRAM 30 m Large Program whose aim is determining the elemental depletions and the ionization fraction in a set of prototypical star-forming regions. This paper presents the first results from the prototypical dark cloud Taurus molecular cloud (TMC) 1. Extensive millimeter observations have been carried out with the IRAM 30 m telescope (…
Kinematics of Circumgalactic Gas: Feeding Galaxies and Feedback
Martin, Crystal L.; Kacprzak, Glenn G.; Churchill, Christopher W. +1 more
We present observations of 50 pairs of redshift z ≈ 0.2 star-forming galaxies and background quasars. These sightlines probe the circumgalactic medium (CGM) out to half the virial radius, and we describe the circumgalactic gas kinematics relative to the reference frame defined by the galactic disks. We detect halo gas in Mg II absorption, measure …
Climate of an ultra hot Jupiter. Spectroscopic phase curve of WASP-18b with HST/WFC3
Fortney, Jonathan J.; Stevenson, Kevin B.; Désert, Jean-Michel +6 more
We present the analysis of a full-orbit, spectroscopic phase curve of the ultra hot Jupiter (UHJ) WASP-18b, obtained with the Wide Field Camera 3 aboard the Hubble Space Telescope. We measured the normalised day-night contrast of the planet as >0.96 in luminosity: the disc-integrated dayside emission from the planet is at 964 ± 25 ppm, correspo…
Gravitationally lensed quasars in Gaia - III. 22 new lensed quasars from Gaia data release 2
McMahon, Richard G.; Auger, Matthew W.; Lemon, Cameron A.
We report the discovery and spectroscopic confirmation of 22 new gravitationally lensed quasars found using Gaia data release 2. The selection was made using several techniques: multiple Gaia detections around objects in quasar candidate catalogues, modelling of unWISE coadd pixels using Gaia astrometry, and Gaia detections offset from photometric…
Gaia Cepheid parallaxes and 'Local Hole' relieve H0 tension
Metcalfe, N.; Shanks, T.; Hogarth, L. M.
There is an ≈9 ± 2.5 per cent tension between the value of Hubble's Constant, H0 = 67.4 ± 0.5 km s-1 Mpc-1, implied by the Planck microwave background power spectrum and that given by the distance scale of H0 = 73.4 ± 1.7 km s-1Mpc-1. But with a plausible assumption about a Gaia DR2…
Microlensing Optical Depth and Event Rate toward the Galactic Bulge from 8 yr of OGLE-IV Observations
Udalski, Andrzej; Mróz, Przemek; Szymański, Michał K. +9 more
The number and properties of observed gravitational microlensing events depend on the distribution and kinematics of stars and other compact objects along the line of sight. In particular, precise measurements of the microlensing optical depth and event rate toward the Galactic bulge enable strict tests of competing models of the Milky Way. Previo…
The X-ray properties of z > 6 quasars: no evident evolution of accretion physics in the first Gyr of the Universe
Bauer, F. E.; Brandt, W. N.; Vignali, C. +10 more
Context. X-ray emission from quasars (QSOs) has been used to assess supermassive black hole accretion properties up to z ≈ 6. However, at z > 6 only ≈15 QSOs are covered by sensitive X-ray observations, preventing a statistically significant investigation of the X-ray properties of the QSO population in the first Gyr of the Universe.
Aims:…
Expanding associations in the Vela-Puppis region. 3D structure and kinematics of the young population
Jordi, C.; Cantat-Gaudin, T.; Balaguer-Núñez, L. +9 more
Context. The Vela-Puppis region is known to host the Vela OB2 association as well as several young clusters featuring OB and pre-main-sequence stars. Several spatial and kinematic subgroups have been identified in recent years.
Aims: By grouping stars based on their positions and velocity, we can address the question of the dynamical history …
Extended stellar systems in the solar neighborhood . II. Discovery of a nearby 120° stellar stream in Gaia DR2
Meingast, Stefan; Alves, João; Fürnkranz, Verena
We report the discovery of a large, dynamically cold, coeval stellar stream that is currently traversing the immediate solar neighborhood at a distance of only 100 pc. The structure was identified in a wavelet decomposition of the 3D velocity space of all stars within 300 pc of the Sun. Its members form a highly elongated structure with a length o…
Implications of the Warm Corona and Relativistic Reflection Models for the Soft Excess in Mrk 509
Steiner, James F.; Wilms, Jörn; Ricci, Claudio +15 more
We present the analysis of the first Nuclear Spectroscopic Telescope Array observations (∼220 ks), simultaneous with the last Suzaku observations (∼50 ks), of the active galactic nucleus of the bright Seyfert 1 galaxy Mrk 509. The time-averaged spectrum in the 1-79 keV X-ray band is dominated by a power-law continuum (Γ ∼ 1.8-1.9), a strong soft e…