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Observational effects of a running Planck mass
Huang, Zhiqi
We consider observational effects of a running effective Planck mass in the scalar-tensor gravity theory. At the background level, an increasing effective Planck mass allows a larger Hubble constant H0, which is more compatible with the local direct measurements. At the perturbative level, for cosmic microwave background (CMB) anisotrop…
Spheroidal and ellipsoidal harmonic expansions of the gravitational potential of small Solar System bodies. Case study: Comet 67P/Churyumov-Gerasimenko
Reimond, Stefan; Baur, Oliver
Gravitational features are a fundamental source of information to learn more about the interior structure and composition of planets, moons, asteroids, and comets. Gravitational field modeling typically approximates the target body with a sphere, leading to a representation in spherical harmonics. However, small celestial bodies are often irregula…
Astrometry with MCAO: HST-GeMS proper motions in the globular cluster NGC 6681
Massari, D.; Stetson, P. B.; Bono, G. +7 more
Aims: For the first time the astrometric capabilities of the Gemini Multi-Conjugate Adaptive Optics System (GeMS) facility at the Gemini South Adaptive Optics Imager (GSAOI) camera on Gemini-South are tested to quantify the accuracy in determining stellar proper motions in the Galactic globular cluster NGC 6681.
Methods: Proper motions f…
On the distance to the North Polar Spur and the local CO-H2 factor
Casandjian, J. M.; Kuntz, K. D.; Lallement, R. +4 more
Aims: Most models identify the X-ray bright North Polar Spur (NPS) with a hot interstellar (IS) bubble in the Sco-Cen star-forming region at ≃130 pc. An opposite view considers the NPS as a distant structure associated with Galactic nuclear outflows. Constraints on the NPS distance can be obtained by comparing the foreground IS gas column inf…
Thermal Pressures in the Interstellar Medium of the Magellanic Clouds
York, Donald G.; Lauroesch, James T.; Welty, Daniel E. +1 more
We discuss the thermal pressures (nHT) in predominantly cold, neutral interstellar gas in the Magellanic Clouds, derived from analyses of the fine-structure excitation of neutral carbon, as seen in high-resolution Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra of seven diverse sight lines in the LMC and SMC. Detaile…
Kiloparsec Mass/Light Offsets in the Galaxy Pair-Lyα Emitter Lens System SDSS J1011+0143
Brownstein, Joel R.; Dey, Arjun; Spinrad, Hyron +5 more
We report the discovery of significant mass/light offsets in the strong gravitational lensing system SDSS J1011+0143. We use the high-resolution Hubble Space Telescope (HST) F555W- and F814W-band imaging and Sloan Digital Sky Survey (SDSS) spectroscopy of this system, which consists of a close galaxy pair with a projected separation of ≈ 4.2 {{kpc…
Isolated magnetic field structures in Mercury's magnetosheath as possible analogues for terrestrial magnetosheath plasmoids and jets
Karlsson, Tomas; Raines, Jim M.; Liljeblad, Elisabet +3 more
We have investigated MESSENGER magnetic field data from the Mercury magnetosheath and near solar wind, to identify isolated magnetic field structures (defined as clear, isolated changes in the field magnitude). Their properties are studied in order to determine if they may be considered as analogues to plasmoids and jets known to exist in Earth's …
The amazing diversity in the hot gas content of an X-ray unbiased massive galaxy clusters sample
Andreon, S.; Moretti, A.; Trinchieri, G. +1 more
We aim to determine the intrinsic variety, at a given mass, of the properties of the intracluster medium in clusters of galaxies. This requires a cluster sample selected independently of the intracluster medium content for which reliable masses and subsequent X-ray data can be obtained. We present one such sample, consisting of 34 galaxy clusters …
Electric fields associated with small-scale magnetic holes in the plasma sheet: Evidence for electron currents
Stawarz, Julia E.; Goodrich, Katherine A.; Ergun, Robert E.
We report observations of magnetic holes (MHs) in the near-Earth (8 RE to 12 RE) plasma sheet that have physical sizes perpendicular to the magnetic field (B) on the order of the ion Larmor radius (ρi) and, more importantly, have current layers less than ρi in thickness. Small-scale MHs can have >90% …
A comment on power-law inflation with a dark radiation component
Di Valentino, Eleonora; Bouchet, François R.
Tram et al. 2016 recently pointed out in [1] that power-law inflation in presence of a dark radiation component may relieve the 3.3 σ tension which exists within standard ΛCDM between the determination of the local value of the Hubble constant by Riess et al. (2016) [2] and the value derived from CMB anisotropy data [3] by the Planck collaboration…