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New Near-infrared Period-Luminosity-Metallicity Relations for RR Lyrae Stars and the Outlook for Gaia
Luri, X.; Clementini, G.; Ripepi, V. +6 more
We present results of the analysis of 70 RR Lyrae stars located in the bar of the Large Magellanic Cloud (LMC). Combining the spectroscopically determined metallicity of these stars from the literature with precise periods from the OGLE III catalog and multi-epoch Ks photometry from the VISTA survey of the Magellanic Clouds system, we d…
Emergent cosmology, inflation and dark energy
Herrera, Ramón; Guendelman, Eduardo; Labrana, Pedro +2 more
A new class of gravity-matter models defined in terms of two independent non-Riemannian volume forms (alternative generally covariant integration measure densities) on the space-time manifold are studied in some detail. These models involve an additional (square of the scalar curvature) term as well as scalar matter field potentials of appropriate…
The Azimuthal Dependence of Outflows and Accretion Detected Using O VI Absorption
Charlton, Jane C.; Kacprzak, Glenn G.; Churchill, Christopher W. +2 more
We report a bimodality in the azimuthal angle (Φ) distribution of gas around galaxies traced by O vi absorption. We present the mean Φ probability distribution function of 29 Hubble Space Telescope-imaged O vi absorbing (EW > 0.1 Å) and 24 non-absorbing (EW < 0.1 Å) isolated galaxies (0.08 \lt z \lt 0.67) within ∼200 kpc of background quasar…
Illuminating a Dark Lens : A Type Ia Supernova Magnified by the Frontier Fields Galaxy Cluster Abell 2744
Richard, Johan; Treu, Tommaso; Broadhurst, Tom +27 more
SN HFF14Tom is a Type Ia SN discovered at z=1.3457+/- 0.0001 behind the galaxy cluster Abell 2744 (z = 0.308). In a cosmology-independent analysis, we find that HFF14Tom is 0.77 ± 0.15 mag brighter than unlensed Type Ia SNe at similar redshift, implying a lensing magnification of {µ }{obs}=2.03+/- 0.29. This observed magnification…
Direct Imaging of an Asymmetric Debris Disk in the HD 106906 Planetary System
Murray-Clay, Ruth; Dong, Ruobing; Oppenheimer, Rebecca +53 more
We present the first scattered light detections of the HD 106906 debris disk using the Gemini/Gemini Planet Imager in the infrared and Hubble Space Telescope (HST)/Advanced Camera for Surveys in the optical. HD 106906 is a 13 Myr old F5V star in the Sco-Cen association, with a previously detected planet-mass candidate HD 106906b projected 650 AU f…
Comets as collisional fragments of a primordial planetesimal disk
Rickman, H.; Morbidelli, A.
Context. The Rosetta mission and its exquisite measurements have revived the debate on whether comets are pristine planetesimals or collisionally evolved objects.
Aims: We investigate the collisional evolution experienced by the precursors of current comet nuclei during the early stages of the solar system in the context of the so-called Nice…
Effect of primordial magnetic fields on the ionization history
Finelli, F.; Paoletti, D.; Rubiño-Martín, J. A. +1 more
Primordial magnetic fields (PMF) damp at scales smaller than the photon diffusion and free-streaming scale. This leads to heating of ordinary matter (electrons and baryons), which affects both the thermal and ionization history of our Universe. Here, we study the effect of heating due to ambipolar diffusion and decaying magnetic turbulence. We fin…
Low-level accretion in neutron star X-ray binaries
Altamirano, D.; Degenaar, N.; Wijnands, R. +5 more
We search the literature for reports on the spectral properties of neutron star low-mass X-ray binaries when they have accretion luminosities between 1034 and 1036 erg s-1, corresponding to roughly 0.01-1 per cent of the Eddington accretion rate for a neutron star. We found that in this luminosity range the photon …
Anatomy of the AGN in NGC 5548. II. The spatial, temporal, and physical nature of the outflow from HST/COS Observations
Kaastra, J. S.; Harrison, F. A.; Kriss, G. A. +30 more
Context. AGN outflows are thought to influence the evolution of their host galaxies and of super massive black holes. Our deep multiwavelength campaign on NGC 5548 has revealed a new, unusually strong X-ray obscuration, accompanied by broad UV absorption troughs observed for the first time in this object. The X-ray obscuration caused a dramatic de…
Hubble Space Telescope Proper Motion (HSTPROMO) Catalogs of Galactic Globular Clusters. III. Dynamical Distances and Mass-to-Light Ratios
Anderson, Jay; van der Marel, Roeland P.; Watkins, Laura L. +1 more
We present dynamical distance estimates for 15 Galactic globular clusters (GCs) and use these to check the consistency of dynamical and photometric distance estimates. For most of the clusters, this is the first dynamical distance estimate ever determined. We extract proper-motion (PM) dispersion profiles using cleaned samples of bright stars from…