Search Publications
Is the Milky Way still breathing? RAVE-Gaia streaming motions
Gilmore, G.; Freeman, K. C.; Watson, F. +26 more
We use data from the Radial Velocity Experiment (RAVE) and the Tycho-Gaia astrometric solution (TGAS) catalogue to compute the velocity fields yielded by the radial (VR), azimuthal (Vϕ),and vertical (Vz) components of associated Galactocentric velocity. We search in particular for variation in all three velocity co…
Coupling hydrodynamics with comoving frame radiative transfer. II. Stellar wind stratification in the high-mass X-ray binary Vela X-1
Hamann, W. -R.; Oskinova, L. M.; Sander, A. A. C. +5 more
Context. Vela X-1, a prototypical high-mass X-ray binary (HMXB), hosts a neutron star (NS) in a close orbit around an early-B supergiant donor star. Accretion of the donor star's wind onto the NS powers its strong X-ray luminosity. To understand the physics of HMXBs, detailed knowledge about the donor star winds is required.
Aims: To gain a r…
Enhancing SDO/HMI images using deep learning
Asensio Ramos, A.; Díaz Baso, C. J.
Context. The Helioseismic and Magnetic Imager (HMI) provides continuum images and magnetograms with a cadence better than one per minute. It has been continuously observing the Sun 24 h a day for the past 7 yr. The trade-off between full disk observations and spatial resolution means that HMI is not adequate for analyzing the smallest-scale events…
Periastron Observations of TeV Gamma-Ray Emission from a Binary System with a 50-year Period
Maraschi, L.; Covino, S.; Antonelli, L. A. +211 more
We report on observations of the pulsar/Be star binary system PSR J2032+4127/MT91 213 in the energy range between 100 {GeV} and 20 {TeV} with the Very Energetic Radiation Imaging Telescope Array and Major Atmospheric Gamma Imaging Cherenkov telescope arrays. The binary orbit has a period of approximately 50 years, with the most recent periastron o…
Outflows in the narrow-line region of bright Seyfert galaxies - I. GMOS-IFU data
Kraemer, S. B.; Crenshaw, D. M.; Elvis, M. +7 more
We present two-dimensional maps of emission-line fluxes and kinematics, as well as of the stellar kinematics of the central few kpc of five bright nearby Seyfert galaxies - Mrk 6, Mrk 79, Mrk 348, Mrk 607, and Mrk 1058 - obtained from observations with the Gemini Multi-Object Spectrograph Integral Field Unit on the Gemini North Telescope. The data…
Limits on Clouds and Hazes for the TRAPPIST-1 Planets
Moran, Sarah E.; Batalha, Natasha E.; Wakeford, Hannah R. +2 more
The TRAPPIST-1 planetary system is an excellent candidate for study of the evolution and habitability of M-dwarf-hosted planets. Transmission spectroscopy observations performed on the system with the Hubble Space Telescope (HST) suggest that the innermost five planets do not possess clear hydrogen atmospheres. Here we reassess these conclusions w…
Element Abundance Ratios in the Quiet Sun Transition Region
Young, P. R.
Element abundance ratios of magnesium to neon (Mg/Ne) and neon to oxygen (Ne/O) in the transition region of the quiet Sun have been derived by re-assessing previously published data from the Coronal Diagnostic Spectrometer on board the Solar and Heliospheric Observatory in the light of new atomic data. The quiet Sun Mg/Ne ratio is important for as…
Interrogating Seyferts with NebulaBayes: Spatially Probing the Narrow-line Region Radiation Fields and Chemical Abundances
Kewley, Lisa J.; Blanc, Guillermo A.; Hopkins, Andrew M. +4 more
NebulaBayes is a new Bayesian code that implements a general method of comparing observed emission-line fluxes to photoionization model grids. The code enables us to extract robust, spatially resolved measurements of abundances in the extended narrow-line regions (ENLRs) produced by Active Galactic Nuclei (AGN). We observe near-constant ionization…
Broad Non-Gaussian Fe XXIV Line Profiles in the Impulsive Phase of the 2017 September 10 X8.3-class Flare Observed by Hinode/EIS
Reeves, Katharine K.; Polito, Vanessa; Chen, Bin +4 more
We analyze the spectra of high-temperature Fe XXIV lines observed by the Hinode/Extreme-Ultraviolet Imaging Spectrometer (EIS) during the impulsive phase of the X8.3-class flare on 2017 September 10. The line profiles are broad, show pronounced wings, and clearly depart from a single-Gaussian shape. The lines can be well fitted with κ distribution…
HD 169142 in the eyes of ZIMPOL/SPHERE
Avenhaus, H.; Casassus, S.; Wolf, S. +5 more
We present new data of the protoplanetary disc surrounding the Herbig Ae/Be star HD 169142 obtained in the very broad-band (VBB) with the Zurich imaging polarimeter (ZIMPOL), a subsystem of the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE) at the Very Large Telescope (VLT). Our Polarimetric Differential Imaging (PDI) ob…