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Helical Kink Instability in a Confined Solar Eruption
Kliem, Bernhard; Hassanin, Alshaimaa
A model for strongly writhing confined solar eruptions suggests an origin in the helical kink instability of a coronal flux rope that remains stable against the torus instability. This model is tested against the well observed filament eruption on 2002 May 27 in a parametric MHD simulation study that comprises all phases of the event. Good agreeme…
Discovery of alunite in Cross crater, Terra Sirenum, Mars: Evidence for acidic, sulfurous waters
Murchie, Scott L.; Ehlmann, Bethany L.; Mustard, John F. +11 more
Matching dust emission structures and magnetic field in high-latitude cloud L1642: comparing Herschel and Planck maps
Juvela, M.; Montier, L.; Ristorcelli, I. +7 more
The nearby cloud L1642 is one of only two known very high latitude (|b| > 30 deg) clouds actively forming stars. It is a rare example of star formation in isolated conditions, and can reveal important details of star formation in general, e.g. of the effect of magnetic fields. We compare Herschel dust emission structures and magnetic field orie…
The F-GAMMA programme: multi-frequency study of active galactic nuclei in the Fermi era. Programme description and the first 2.5 years of monitoring
Pearson, T. J.; Nestoras, I.; Zensus, J. A. +15 more
Context. To fully exploit the scientific potential of the Fermi mission for the physics of active galactic nuclei (AGN), we initiated the F-GAMMA programme. Between 2007 and 2015 the F-GAMMA was the prime provider of complementary multi-frequency monitoring in the radio regime.
Aims: We quantify the radio variability of γ-ray blazars. We inve…
SU Lyncis, a hard X-ray bright M giant: clues point to a large hidden population of symbiotic stars
Nuñez, N. E.; Nelson, T.; Mukai, K. +6 more
Symbiotic star surveys have traditionally relied almost exclusively on low resolution optical spectroscopy. However, we can obtain a more reliable estimate of their total Galactic population by using all available signatures of the symbiotic phenomenon. Here we report the discovery of a hard X-ray source, 4PBC J0642.9+5528, in the Swift hard X-ray…
Timing the warm absorber in NGC 4051
Costantini, E.; Uttley, P.; Silva, C. V.
We investigated, using spectral-timing analysis, the characterization of highly ionized outflows in Seyfert galaxies, the so-called warm absorbers. Here, we present our results of the extensive 600 ks of XMM-Newton archival observations of the bright and highly variable Seyfert 1 galaxy NGC 4051 whose spectrum has revealed a complex multicomponent…
Evidence for the thermal Sunyaev-Zel'dovich effect associated with quasar feedback
Hilton, Matt; Sifón, Cristóbal; Bond, J. Richard +20 more
Using a radio-quiet subsample of the Sloan Digital Sky Survey spectroscopic quasar catalogue, spanning redshifts 0.5-3.5, we derive the mean millimetre and far-infrared quasar spectral energy distributions (SEDs) via a stacking analysis of Atacama Cosmology Telescope and Herschel-Spectral and Photometric Imaging REceiver data. We constrain the for…
Subarcsecond international LOFAR radio images of Arp 220 at 150 MHz. A kpc-scale star forming disk surrounding nuclei with shocked outflows
Beswick, R.; Gallagher, J. S.; Horellou, C. +16 more
Context. Arp 220 is the prototypical ultra luminous infrared galaxy (ULIRG). Despite extensive studies, the structure at MHz-frequencies has remained unknown because of limits in spatial resolution.
Aims: This work aims to constrain the flux and shape of radio emission from Arp 220 at MHz frequencies.
Methods: We analyse new observations…
Optical Spectroscopic Observations of Gamma-ray Blazar Candidates. V. TNG, KPNO, and OAN Observations of Blazar Candidates of Uncertain Type in the Northern Hemisphere
Smith, Howard A.; Masetti, N.; Jiménez-Bailón, E. +12 more
The extragalactic γ-ray sky is dominated by emission from blazars, a peculiar class of active galactic nuclei. Many of the γ-ray sources included in the Fermi-Large Area Telescope Third Source catalog (3FGL) are classified as blazar candidates of uncertain type (BCUs) because there are no optical spectra available in the literature to confirm thei…
Primordial features and Planck polarization
Starobinsky, Alexei A.; Hazra, Dhiraj Kumar; Smoot, George F. +1 more
With the Planck 2015 Cosmic Microwave Background (CMB) temperature and polarization data, we search for possible features in the primordial power spectrum (PPS). We revisit the Wiggly Whipped Inflation (WWI) framework and demonstrate how generation of some particular primordial features can improve the fit to Planck data. WWI potential allows the …