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Variations between Dust and Gas in the Diffuse Interstellar Medium. III. Changes in Dust Properties
Heiles, Carl; Reach, William T.; Bernard, Jean-Philippe +1 more
We study infrared emission of 17 isolated, diffuse clouds with masses of order {10}2 {M}⊙ to test the hypothesis that grain property variations cause the apparently low gas-to-dust ratios that have been measured in those clouds. Maps of the clouds were constructed from Wide-field Infrared Survey Explorer (WISE) data and dire…
Shocks and Spatially Offset Active Galactic Nuclei Produce Velocity Offsets in Emission Lines
Greene, Jenny E.; Comerford, Julia M.; Barrows, R. Scott +1 more
While 2% of active galactic nuclei (AGNs) exhibit narrow emission lines with line-of-sight velocities that are significantly offset from the velocity of the host galaxy’s stars, the nature of these velocity offsets is unknown. We investigate this question with Chandra/ACIS and Hubble Space Telescope/Wide Field Camera 3 observations of seven veloci…
Spectral Variability of Two Rapidly Rotating Brown Dwarfs: 2MASS J08354256-0819237 and 2MASS J18212815+1414010
Schlawin, E.; Burgasser, Adam J.; Gizis, J. E. +2 more
L dwarfs exhibit low-level, rotationally modulated photometric variability generally associated with heterogeneous, cloud-covered atmospheres. The spectral character of these variations yields insight into the particle sizes and vertical structure of the clouds. Here, we present the results of a high-precision, ground-based, near-infrared, spectra…
Recovering a redshift-extended varying speed of light signal from galaxy surveys
Salzano, Vincenzo
We investigate a new method to recover (if any) a possible varying speed of light (VSL) signal from cosmological data. It comes as an upgrade by Salzano, Dąbrowski, and Lazkoz [Phys. Rev. Lett.114, 101304 (2015), 10.1103/PhysRevLett.114.101304; Phys. Rev. D 93, 063521 (2016), 10.1103/PhysRevD.93.063521], where it was argued that such a signal coul…
Torus models of the outer disc of the Milky Way using LAMOST survey data
Mao, Shude; Liu, Chao; Wang, Qiao +2 more
With a sample of 48 161 K giant stars selected from the LAMOST DR 2 catalogue, we construct torus models in a large volume extending, for the first time, from the solar vicinity to a Galactocentric distance of ∼20 kpc, reaching the outskirts of the Galactic disc. We show that the kinematics of the K giant stars match conventional models, e.g. as c…
Diurnal variation in martian dust devil activity
Lewis, S. R.; Chapman, R. M.; Balme, M. +1 more
We show that the dust devil parameterisation in use in most Mars Global Circulation Models (MGCMs) results in an unexpectedly high level of dust devil activity during morning hours.
Prior expectations of the diurnal variation of Martian dust devils are based mainly upon the observed behaviour of terrestrial dust devils: i.e. that the majority…CoRoT 223992193: Investigating the variability in a low-mass, pre-main sequence eclipsing binary with evidence of a circumbinary disk
Aigrain, S.; Gandolfi, D.; Bouvier, J. +10 more
CoRoT 223992193 is the only known low-mass, pre-main sequence eclipsing binary that shows evidence of a circumbinary disk. The system displays complex photometric and spectroscopic variability over a range of timescales and wavelengths. Using two optical CoRoT runs from 2008 and 2011/2012 (spanning 23 and 39 days), along with infrared Spitzer 3.6 …
A Suzaku View of Accretion-powered X-Ray Pulsar GX 1+4
Hoshino, Akio; Naik, Sachindra; Kitamoto, Shunji +3 more
We present results obtained from a Suzaku observation of the accretion-powered X-ray pulsar GX 1+4. A broadband continuum spectrum of the pulsar was found to be better described by a simple model consisting of a blackbody component and an exponential cutoff power law than the previously used compTT continuum model. Though the pulse profile had a s…
The Uncertainty of Local Background Magnetic Field Orientation in Anisotropic Plasma Turbulence
Saur, J.; Gerick, F.; von Papen, M.
In order to resolve and characterize anisotropy in turbulent plasma flows, a proper estimation of the background magnetic field is crucially important. Various approaches to calculating the background magnetic field, ranging from local to globally averaged fields, are commonly used in the analysis of turbulent data. We investigate how the uncertai…
First results from SAM-FP: Fabry-Perot observations with ground-layer adaptive optics - the structure and kinematics of the core of 30 Doradus
Mendes de Oliveira, C.; Barbá, R.; Amram, P. +3 more
The aim of this paper is to present the first data set obtained with SOAR Adaptive Module-Fabry-Parot (SAM-FP), a Fabry-Perot instrument mounted inside the SOAR telescope Adaptive-Optics Module. This is the only existing imaging Fabry-Perot interferometer using laser-assisted ground-layer adaptive optics. SAM-FP was used to observe the ionized gas…