Search Publications
First evidence of non-Gaussian solar flare EUV spectral line profiles and accelerated non-thermal ion motion
Fletcher, Lyndsay; Jeffrey, Natasha L. S.; Labrosse, Nicolas
Context. The properties of solar flare plasma can be determined from the observation of optically thin lines. The emitting ion distribution determines the shape of the spectral line profile, with an isothermal Maxwellian ion distribution producing a Gaussian profile. Non-Gaussian line profiles may indicate more complex ion distributions.
Aims…
Slow electrostatic solitary waves in Earth's plasma sheet boundary layer
Fazakerley, Andrew; Omura, Yoshiharu; Anekallu, Chandrasekhar +3 more
We modeled Cluster spacecraft observations of slow electrostatic solitary waves (SESWs) in the Earth's northern plasma sheet boundary layer (PSBL) region on the basis of nonlinear fluid theory and fluid simulation. Various plasma parameters observed by the Cluster satellite at the time of the SESWs were examined to investigate the generation proce…
The mosaic multiple stellar populations in ω Centauri: the horizontal branch and the main sequence
Di Criscienzo, M.; D'Antona, F.; Tailo, M. +2 more
We interpret the stellar population of ω Centauri by means of a population synthesis analysis, following the most recent observational guidelines for input metallicities, helium and [(C+N+O)/Fe] contents. We deal at the same time with the main sequences, sub-giant and horizontal branch (HB) data. The reproduction of the observed colour-magnitude f…
Deep Chandra observation and numerical studies of the nearest cluster cold front in the sky
Simionescu, A.; Fabian, A. C.; Markevitch, M. +9 more
We present the results of a very deep (500 ks) Chandra observation, along with tailored numerical simulations, of the nearest, best resolved cluster cold front in the sky, which lies 90 kpc (19 arcmin) to the north-west of M 87. The northern part of the front appears the sharpest, with a width smaller than 2.5 kpc (1.5 Coulomb mean free paths; at …
Formation of downstream high-speed jets by a rippled nonstationary quasi-parallel shock: 2-D hybrid simulations
Lu, Q.; Lembege, B.; Hao, Y. +1 more
Experimental observations from space missions (including more recently Cluster and Time History of Events and Macroscale Interactions during Substorms data) have clearly revealed the existence of high-speed jets (HSJs) in the downstream region of the quasi-parallel terrestrial bow shock. Presently, two-dimensional hybrid simulations are performed …
Herschel protocluster survey: a search for dusty star-forming galaxies in protoclusters at z = 2-3
Lehmer, B. D.; Smail, Ian; Alexander, D. M. +15 more
We present a Herschel/Spectral and Photometric Imaging Receiver (SPIRE) survey of three protoclusters at z = 2-3 (2QZCluster, HS1700, SSA22). Based on the SPIRE colours (S350/S250 and S500/S350) of 250 µm sources, we selected high-redshift dusty star-forming galaxies potentially associated with the…
Observational Constraints on Planet Nine: Cassini Range Observations
Holman, Matthew J.; Payne, Matthew J.
We examine the tidal perturbations induced by a possible additional, distant planet in the solar system on the distance between the Earth and the Cassini spacecraft. We find that measured range residuals alone can significantly constrain the sky position, distance, and mass of the perturbing planet to sections of the sky essentially orthogonal to …
NuSTAR and XMM-Newton Observations of the Hard X-Ray Spectrum of Centaurus A
Harrison, F. A.; Stern, D.; Farrah, D. +28 more
We present simultaneous XMM-Newton and Nuclear Spectroscopic Telescope Array (NuSTAR) observations spanning 3-78 keV of the nearest radio galaxy, Centaurus A (Cen A). The accretion geometry around the central engine in Cen A is still debated, and we investigate possible configurations using detailed X-ray spectral modeling. NuSTAR imaged the centr…
Planck intermediate results. XLIII. Spectral energy distribution of dust in clusters of galaxies
Kneissl, R.; Miville-Deschênes, M. -A.; Planck Collaboration +179 more
Although infrared (IR) overall dust emission from clusters of galaxies has been statistically detected using data from the Infrared Astronomical Satellite (IRAS), it has not been possible to sample the spectral energy distribution (SED) of this emission over its peak, and thus to break the degeneracy between dust temperature and mass. By complemen…
Constraints on the running of the running of the scalar tilt from CMB anisotropies and spectral distortions
Di Valentino, Eleonora; Melchiorri, Alessandro; Cabass, Giovanni +2 more
We use the recent observations of cosmic microwave background (CMB) temperature and polarization anisotropies provided by the Planck satellite experiment to place constraints on the running αs=d ns/d log k and the running of the running βs=d αs/d log k of the spectral index ns of primordial sc…