Search Publications
Does black hole growth depend fundamentally on host-galaxy compactness?
Alexander, D. M.; Brandt, W. N.; Xue, Y. Q. +5 more
Possible connections between central black hole (BH) growth and host-galaxy compactness have been found observationally, which may provide insight into BH-galaxy coevolution: compact galaxies might have large amounts of gas in their centres due to their high mass-to-size ratios, and simulations predict that high central gas density can boost BH ac…
Revisiting the HIP 41378 System with K2 and Spitzer
Gorjian, Varoujan; Kane, Stephen R.; Schlieder, Joshua E. +12 more
We present new observations of the multiplanet system HIP 41378, a bright star (V = 8.9, K s = 7.7) with five known transiting planets. Previous K2 observations showed multiple transits of two Neptune-sized bodies and single transits of three larger planets (R P = 0.33R J , 0.47R J , 0.88R J …
Mass variance from archival X-ray properties of Dark Energy Survey Year-1 galaxy clusters
Smith, M.; Annis, J.; Brooks, D. +77 more
Using archival X-ray observations and a lognormal population model, we estimate constraints on the intrinsic scatter in halo mass at fixed optical richness for a galaxy cluster sample identified in Dark Energy Survey Year-One (DES-Y1) data with the redMaPPer algorithm. We examine the scaling behaviour of X-ray temperatures, TX, with opt…
Efficient Calculation of Non-local Thermodynamic Equilibrium Effects in Multithreaded Hydrodynamic Simulations of Solar Flares
Warren, Harry P.; Crump, Nicholas A.; Bradshaw, Stephen J. +1 more
Understanding the dynamics of the chromosphere is crucial to understanding energy transport across the solar atmosphere. The chromosphere is optically thick at many wavelengths and described by non-local thermodynamic equilibrium (NLTE), making it difficult to interpret observations. Furthermore, there is considerable evidence that the atmosphere …
The EBLM project. VI. Mass and radius of five low-mass stars in F+M binaries discovered by the WASP survey
Bouchy, F.; Queloz, D.; Ségransan, D. +26 more
Some M-dwarfs around F-/G-type stars have been measured to be hotter and larger than predicted by stellar evolution models. Inconsistencies between observations and models need to be addressed with more mass, radius, and luminosity measurements of low-mass stars to test and refine evolutionary models. Our aim is to measure the masses, radii and ag…
Metallic-line Stars Identified from Low-resolution Spectra of LAMOST DR5
Qin, Li; Luo, A. -Li; Hou, Wen +6 more
The Large Sky Area Multi-Object Fibre Spectroscopic Telescope data release 5 (DR5) released more than 200,000 low-resolution spectra of early-type stars with a signal-to-noise ratio > 50. The search for metallic-line (Am) stars in such a large database and a study of their statistical properties are presented in this paper. Six machine-learning…
Mapping the Galactic Disk with the LAMOST and Gaia Red Clump Sample. III. A New Velocity Substructure and Time Stamps of the Galactic Disk Asymmetry in the Disk between 12 and 15 kpc
Huang, Y.; Chen, B. -Q.; Wang, C. +11 more
We investigate the three-dimensional asymmetrical kinematics and present time stamps of the Milky Way disk between Galactocentric distances of R = 12 and 15 kpc, using red clump stars selected from the LAMOST Galactic survey, also with proper motion measurements provided by the Gaia DR2. We discover velocity substructure above the Galactic plane c…
Gaia-DR2 distance to the W3 Complex in the Perseus Arm
Damineli, Augusto; Navarete, Felipe; Galli, Phillip A. B.
The Perseus Arm is the closest Galactic spiral arm from the Sun, offering an excellent opportunity to study in detail its stellar population. However, its distance has been controversial with discrepancies by a factor of two. Kinematic distances are in the range 3.9-4.2 kpc as compared to 1.9-2.3 kpc from spectrophotometric and trigonometric paral…
Exposing the plural nature of molecular clouds. Extracting filaments and the cosmic infrared background against the true scale-free interstellar medium
Schneider, N.; Bontemps, S.; Elia, D. +2 more
We present the Multiscale non-Gaussian Segmentation (MnGSeg) analysis technique. This wavelet-based method combines the analysis of the probability distribution function (PDF) of map fluctuations as a function of spatial scales and the power spectrum analysis of a map. This technique allows us to extract the non-Gaussianities identified in the mul…
Observations of Binary Stars with the Differential Speckle Survey Instrument. VIII. Measures of Metal-poor and Triple Stars from 2015 to 2018
Kane, Stephen R.; Howell, Steve B.; Hirsch, Lea A. +15 more
We present 248 speckle observations of 43 binary and 19 trinary star systems chosen to make progress in two main areas of investigation: the fundamental properties of metal-poor stars and star formation mechanisms. The observations were taken at the Gemini North and South telescopes during the period 2015 July to 2018 April, mainly with the Differ…