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The Kinematics of the Permitted C II λ6578 Line in a Large Sample of Planetary Nebulae
Suárez, Genaro; Richer, Michael G.; López, José Alberto +1 more
We present spectroscopic observations of the C II λ6578 permitted line for 83 lines of sight in 76 planetary nebulae at high spectral resolution, most of them obtained with the Manchester Echelle Spectrograph on the 2.1 m telescope at the Observatorio Astronómico Nacional on the Sierra San Pedro Mártir. We study the kinematics of the C II λ6578 pe…
New Fe I Level Energies and Line Identifications from Stellar Spectra. II. Initial Results from New Ultraviolet Spectra of Metal-poor Stars
Ayres, Thomas R.; Peterson, Ruth C.; Kurucz, Robert L.
The Fe I spectrum is critical to many areas of astrophysics, yet many of the high-lying levels remain uncharacterized. To remedy this deficiency, Peterson & Kurucz identified Fe I lines in archival ultraviolet and optical spectra of metal-poor stars, whose warm temperatures favor moderate Fe I excitation. Sixty-five new levels were recovered, …
Hale cycle and long-term trend in variation of galactic cosmic rays related to solar rotation
Mursula, K.; Gil, A.
Context. Galactic cosmic ray (GCR) intensities around solar minimum times are modulated by magnetic drifts that depend on the overall solar polarity. GCR intensities reach a higher but more narrow peak during negative minima than during positive minima. However, despite these higher intensities, the variation of GCRs over timescales of solar rotat…
ZFIRE: Similar Stellar Growth in Hα-emitting Cluster and Field Galaxies at z ~ 2
Papovich, Casey; Kewley, Lisa J.; Kacprzak, Glenn G. +13 more
We compare galaxy scaling relations as a function of environment at z∼ 2 with our ZFIRE survey12 where we have measured Hα fluxes for 90 star-forming galaxies selected from a mass-limited ({log}({M}\star /{M}⊙ )> 9) sample based on ZFOURGE.13 The cluster galaxies (37) are part of a confirmed system at…
Interplay of dust alignment, grain growth, and magnetic fields in polarization: lessons from the emission-to-extinction ratio
Boulanger, F.; Guillet, V.; Jones, A. P. +1 more
Context. Polarized extinction and emission from dust in the interstellar medium (ISM) are hard to interpret, as their dependence on dust optical properties, grain alignment, and magnetic field orientation is complex. This is particularly true in molecular clouds. The aforementioned phenomena are usually considered independently in polarization stu…
A Catalog Sample of Low-mass Galaxies Observed in X-Rays with Central Candidate Black Holes
Nucita, A. A.; De Paolis, F.; Ingrosso, G. +2 more
We present a sample of X-ray-selected candidate black holes in 51 low-mass galaxies with z ≤ 0.055 and masses up to 1010 M ⊙ obtained by cross-correlating the NASA-SLOAN Atlas with the 3XMM catalog. We have also searched in the available catalogs for radio counterparts of the black hole candidates and find that 19 of the prev…
Phase relationship between ULF waves and drift-bounce resonant ions: A statistical study
Zong, Q. G.; Rankin, R.; Wang, Y. F. +4 more
We explore the phase relationship between the poloidal mode ULF wave electric field oscillations and drift-bounce resonant oxygen ions under the resonant condition of N = 2 at the magnetic equator. Using Cluster data from 2001 to 2004, we identify 55 fundamental poloidal mode wave events, among which 42 show "negative slope" pitch angle dispersion…
Abundances of the light elements from UV (HST) and red (ESO) spectra in the very old star HD 84937
Spite, M.; Barbuy, B.; Spite, F. +2 more
Aims: In order to provide a better basis for the study of mechanisms of nucleosynthesis of the light elements beyond hydrogen and helium in the oldest stars, the abundances of C, O, Mg, Si, P, S, K, and Ca have been derived from UV-HST and visible-ESO high resolution spectra in the old, very metal-poor star HD 84937, at a metallicity that is …
AGILE Observations of the Gravitational-wave Source GW170817: Constraining Gamma-Ray Emission from an NS-NS Coalescence
Antonelli, L. A.; Costa, E.; Barbiellini, G. +39 more
The LIGO-Virgo Collaboration (LVC) detected, on 2017 August 17, an exceptional gravitational-wave (GW) event temporally consistent within ∼ 1.7 {{s}} with the GRB 1708117A observed by Fermi-GBM and INTEGRAL. The event turns out to be compatible with a neutron star-neutron star (NS-NS) coalescence that subsequently produced a radio/optical/X-ray tr…
Redshift remapping and cosmic acceleration in dark-matter-dominated cosmological models
Prada, Francisco; Wojtak, Radosław
The standard relation between the cosmological redshift and cosmic scalefactor underlies cosmological inference from virtually all kinds of cosmological observations, leading to the emergence of the Λ cold-dark-matter (ΛCDM) cosmological model. This relation is not a fundamental theory and thus observational determination of this function (redshif…