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Reducing Ground-based Astrometric Errors with Gaia and Gaussian Processes
Bacon, D.; Bechtol, K.; Smith, M. +65 more
Stochastic field distortions caused by atmospheric turbulence are a fundamental limitation to the astrometric accuracy of ground-based imaging. This distortion field is measurable at the locations of stars with accurate positions provided by the Gaia DR2 catalog; we develop the use of Gaussian process regression (GPR) to interpolate the distortion…
The most luminous blue quasars at 3.0 < z < 3.3. II. C IV/X-ray emission and accretion disc physics
Marconi, A.; Vignali, C.; Gilli, R. +12 more
We analyse the properties of the high-ionisation C IVλ1549 broad emission line in connection with the X-ray emission of 30 bright, optically selected quasars at z ≃ 3.0−3.3 with pointed XMM-Newton observations, which were selected to test the suitability of active galactic nuclei as cosmological tools. In our previous work, we found that a large f…
Exploring the hot gaseous halo around an extremely massive and relativistic jet launching spiral galaxy with XMM-Newton
Fabian, A. C.; Ho, L. C.; Combes, F. +6 more
We present a deep XMM-Newton observation of the extremely massive, rapidly rotating, relativistic-jet-launching spiral galaxy 2MASX J23453268-0449256. Diffuse X-ray emission from the hot gaseous halo around the galaxy is robustly detected out to a radius of 160 kpc, corresponding roughly to 35 per cent of the virial radius (≈450 kpc). We fit the X…
Probing the Cold Deep Depths of the California Molecular Cloud: The Icy Relationship between CO and Dust
Alves, João; Lada, Charles J.; Lombardi, Marco +3 more
We study the relationship between molecular gas and dust in the California Molecular Cloud over an unprecedented dynamic range of cloud depth (AV = 3-60 mag). We compare deep Herschel-based measurements of dust extinction with observations of the 12CO, 13CO, and C18O J = 2 - 1 lines on sub-parsec scales …
Multiple Stellar Populations of Globular Clusters from Homogeneous Ca-CN-CH-NH Photometry. VI. M3 (NGC 5272) Is Not a Prototypical Normal Globular Cluster
Sneden, Christopher; Lee, Jae-Woo
We present Ca-CN-CH-NH photometry for the well-known globular cluster (GC) M3 (NGC 5272). We show new evidence for two M3 populations with distinctly different carbon and nitrogen abundances, seen in a sharp division between CN-weak and CN-strong red-giant branches (RGBs) in M3. The CN-strong population shows a C-N anticorrelation that is a natura…
Magnetic Fields of CP Stars in the Orion OB1 Association. V. Stars of Subgroups (c) and (d)
Romanyuk, I. I.; Semenko, E. A.; Moiseeva, A. V. +2 more
—The paper presents the results of magnetic field measurements of 27 chemically peculiar stars in subgroups (c) and (d) of the Orion OB1 association. In total, more than 140 circularly polarized spectra were obtained and measured in the period from 2013 to 2020. An analysis of the results showed that 13 out of 24 CP stars in subgroup (c) have a ma…
A MUSE spectro-imaging study of the Th 28 jet: Precession in the inner jet
Ray, T. P.; Eislöffel, J.; Bacciotti, F. +5 more
Context. Th 28 is a Classical T Tauri star in the Lupus 3 cloud that drives an extended bipolar jet. Previous studies of the inner jet identified signatures of rotation around the outflow axis, a key result for theories of jet launching. Thus this is an important source in which to investigate the poorly understood jet launching mechanism.
Ai…
Probing Protoplanetary Disk Winds with C II Absorption
Herczeg, Gregory J.; France, Kevin; Johns-Krull, Christopher M. +1 more
We present an analysis of wind absorption in the C II λ1335 doublet toward 40 classical T Tauri stars with archival far-ultraviolet (FUV) spectra obtained by the Hubble Space Telescope. Absorption features produced by fast or slow winds are commonly detected (36 out of 40 targets) in our sample. The wind velocity of the fast wind decreases with di…
Toward Precise Galaxy Evolution: A Comparison between Spectral Indices of z 1 Galaxies in the IllustrisTNG Simulation and the LEGA-C Survey
Bell, Eric F.; Maseda, Michael V.; Muzzin, Adam +13 more
We present the first comparison of observed stellar continuum spectra of high-redshift galaxies and mock galaxy spectra generated from hydrodynamical simulations. The mock spectra are produced from the IllustrisTNG TNG100 simulation combined with stellar population models and take into account dust attenuation and realistic observational effects (…
Observing and modelling the young solar analogue EK Draconis: starspot distribution, elemental abundances, and evolutionary status
Solanki, S. K.; Montes, D.; Hussain, G. A. J. +4 more
Observations and modelling of stars with near-solar masses in their early phases of evolution are critical for a better understanding of how dynamos of solar-type stars evolve. We examine the chemical composition and the spot distribution of the pre-main-sequence solar analogue EK Dra. Using spectra from the HERMES Spectrograph (La Palma), we obta…