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Systematic Variations of CO Gas Abundance with Radius in Gas-rich Protoplanetary Disks
Zhang, Ke; Bergin, Edwin A.; Krijt, Sebastiaan +2 more
CO is the most widely used gas tracer of protoplanetary disks. Its abundance is usually assumed to be an interstellar ratio throughout the warm molecular layer of the disk. But recent observations of low CO gas abundance in many protoplanetary disks challenge our understanding of physical and chemical evolutions in disks. Here we investigate the C…
Mapping the Magnetic Interstellar Medium in Three Dimensions over the Full Sky with Neutral Hydrogen
Hensley, Brandon S.; Clark, S. E.
Recent analyses of 21 cm neutral hydrogen (H I) emission have demonstrated that H I gas is organized into linear filamentary structures that are preferentially aligned with the local magnetic field, and that the coherence of these structures in velocity space traces line-of-sight magnetic field tangling. On this basis, we introduce a paradigm for …
ALMA survey of Class II protoplanetary disks in Corona Australis: a young region with low disk masses
Tamura, M.; Galván-Madrid, R.; Testi, L. +20 more
Context. In recent years, the disk populations in a number of young star-forming regions have been surveyed with the Atacama Large Millimeter/submillimeter Array (ALMA). Understanding the disk properties and their correlation with the properties of the central star is critical to understanding planet formation. In particular, a decrease of the ave…
HAWC+/SOFIA Multiwavelength Polarimetric Observations of OMC-1
Morris, Mark R.; Staguhn, Johannes; Ward-Thompson, Derek +36 more
We report new polarimetric and photometric maps of the massive star-forming region OMC-1 using the HAWC+ instrument on the Stratospheric Observatory for Infrared Astronomy. We present continuum polarimetric and photometric measurements of this region at 53, 89, 154, and 214 µm at angular resolutions of 5″, 8″, 14″, and 19″ for the four bands…
Kiloparsec Scale Properties of Star Formation Driven Outflows at z ∼ 2.3 in the SINS/zC-SINF AO Survey
Lutz, D.; Wuyts, S.; Förster Schreiber, N. M. +19 more
We investigate the relationship between star formation activity and outflow properties on kiloparsec scales in a sample of 28 star-forming galaxies at z ∼ 2-2.6, using adaptive optics assisted integral field observations from SINFONI on the Very Large Telescope. The narrow and broad components of the Hα emission are used to simultaneously determin…
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…