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The Gamma-Ray Source AGL J2241+4454 as the Possible Counterpart of MWC 656
Verrecchia, F.; Sabatini, S.; Pittori, C. +5 more
AGILE discovered the transient source AGL J2241+4454 in 2010, which triggered the study of the associated field allowing for the discovery of the first Be/black hole binary system: MWC 656. This binary was suggested to be the counterpart of AGL J2241+4454, but this association is still not robust. In this work we explore the archival AGILE and Fer…
The high-energy gamma-ray detection of G73.9+0.9, a supernova remnant interacting with a molecular cloud
Mikołajewska, Joanna; Chernyakova, Maria; Zdziarski, Andrzej A. +6 more
We have analysed the Fermi Large Area Telescope (LAT) data on the SNR G73.9+0.9. We have confirmed a previous detection of high-energy γ-rays from this source at a high significance of ≃12σ. The observed spectrum shows a significant curvature, peaking in EFE at ∼1 GeV. We have also calculated the flux upper limits in the mm-wavelength a…
Atomic data and density diagnostics for S IV
Del Zanna, G.; Badnell, N. R.
We present a new large-scale R-matrix scattering calculation for S IV. We used the intermediate-coupling frame transformation method and applied term energy corrections. Our calculation has a much larger configuration-interaction and close-coupling expansion than previous calculations. Despite that, we find good agreement in the predicted intensit…
An empirical model of ion plasma in the inner magnetosphere derived from CRRES/MICS measurements
Fennell, J. F.; Claudepierre, S. G.; Chen, M. W. +1 more
We describe an empirical model of energetic ion plasma (∼20-400 keV/q) that is constructed from measurements taken by the Magnetospheric Ion Composition Spectrometer (MICS) instrument that flew on the CRRES spacecraft. This is a unique data set in that it provides energetic ion composition in the near-equatorial ring current region during a very a…
Clues to cometary circular polarization from studying the magnetic field in the vicinity of the nucleus of comet 67P/Churyumov-Gerasimenko
Kolokolova, Ludmilla; Hoang, Thiem; Goetz, Charlotte +4 more
Circular polarization in cometary continuum bands has been observed for more than 30 years. Recently, imaging data on circular polarization have been obtained for more than 10 comets using the 6-m Big Telescope Alt-azimuthal (BTA) telescope (Russia). However, despite the accumulation of significant amounts of data, the mechanisms that form circula…
Departure of High-temperature Iron Lines from the Equilibrium State in Flaring Solar Plasmas
Keenan, F. P.; Kawate, T.; Jess, D. B.
The aim of this study is to clarify if the assumption of ionization equilibrium and a Maxwellian electron energy distribution is valid in flaring solar plasmas. We analyze the 2014 December 20 X1.8 flare, in which the Fe xxi 187 Å, Fe xxii 253 Å, Fe xxiii 263 Å, and Fe xxiv 255 Å emission lines were simultaneously observed by the EUV Imaging Spect…
Overlooked wide companions of nearby F stars
Scholz, R. -D.
Aims: We checked a sample of 545 F stars within 50 pc for wide companions using existing near-infrared and optical sky surveys.
Methods: Applying the common proper motion (CPM) criterion, we detected wide companion candidates with 6-120 arcsec angular separations by visual inspection of multi-epoch finder charts and by searching in prope…
Detection of HF Toward PKS 1830-211, Search for Interstellar H2F+, and Laboratory Study of H2F+ and H2Cl+ Dissociative Recombination
Muller, S.; Black, J. H.; Miyamoto, Y. +7 more
We report extragalactic observations of two fluorine-bearing species, hydrogen fluoride (HF) and fluoronium (H2F+), in the z = 0.89 absorber in front of the lensed blazar PKS 1830-211 with the Atacama Large Millimeter/submillimeter Array. HF was detected toward both southwest and northeast images of the blazar, with column de…
Spectral variation in the supergiant fast X-ray transient SAX J1818.6-1703 observed by XMM-Newton and INTEGRAL
Hill, A. B.; Sidoli, L.; Bird, A. J. +6 more
We present the results of a 30 ks XMM-Newton observation of the supergiant fast X-ray transient (SFXT) SAX J1818.6-1703 - the first in-depth soft X-ray study of this source around periastron. INTEGRAL observations shortly before and after the XMM-Newton observation show the source to be in an atypically active state. Over the course of the XMM-New…
Running cosmological constant with observational tests
Geng, Chao-Qiang; Lee, Chung-Chi; Zhang, Kaituo
We investigate the running cosmological constant model with dark energy linearly proportional to the Hubble parameter, Λ = σH +Λ0, in which the ΛCDM limit is recovered by taking σ = 0. We derive the linear perturbation equations of gravity under the Friedmann-Lemaïtre-Robertson-Walker cosmology, and show the power spectra of the CMB tem…