Search Publications
Detection of Coherent Structures in Photospheric Turbulent Flows
Chian, Abraham C. -L.; Aulanier, Guillaume; Schmieder, Brigitte +4 more
We study coherent structures in solar photospheric flows in a plage in the vicinity of the active region AR 10930 using the horizontal velocity data derived from Hinode/Solar Optical Telescope magnetograms. Eulerian and Lagrangian coherent structures (LCSs) are detected by computing the Q-criterion and the finite-time Lyapunov exponents of the vel…
Precision growth index using the clustering of cosmic structures and growth data
Basilakos, Spyros; Plionis, Manolis; Pouri, Athina
We use the clustering properties of Luminous Red Galaxies (LRGs) and the growth rate data provided by the various galaxy surveys in order to constrain the growth index γ) of the linear matter fluctuations. We perform a standard χ2-minimization procedure between theoretical expectations and data, followed by a joint likelihood analysis a…
Mirror mode structures near Venus and Comet P/Halley
Zhang, T. L.; Baumjohann, W.; Volwerk, M. +4 more
In this paper, we study where mirror mode structures are generated near unmagnetized solar system bodies (Venus and comet P/Halley measured in situ by Venus Express and Giotto). To estimate the location of the mirror mode source region at Venus, we apply a turbulent diffusion model of mirror mode structures, which has already been successfully tes…
Phase-resolved X-Ray Spectra of Magnetars and the Coronal Outflow Model
Beloborodov, Andrei M.; Hascoët, Romain; den Hartog, Peter R.
We test a model recently proposed for the persistent hard X-ray emission from magnetars. In the model, hard X-rays are produced by a decelerating electron-positron flow in the closed magnetosphere. The flow decelerates as it radiates its energy away via resonant scattering of soft X-rays, then it reaches the top of the magnetic loop and annihilate…
Star Formation and Black Hole Growth at z ~= 4.8
Trakhtenbrot, Benny; Netzer, Hagai; Shemmer, Ohad +2 more
We report Herschel/SPIRE, Spitzer and Wide-field Infrared Survey Explorer observations of 44 z ~= 4.8 optically selected active galactic nuclei (AGNs). This flux-limited sample contains the highest mass black holes (BHs) at this redshift. Ten of the objects were detected by Herschel and five show emission that is not clearly associated with the AG…
To the center of cold spot with Planck
Gurzadyan, V. G.; Kashin, A. L.; Sargsyan, S. +3 more
The structure of the cold spot, of a non-Gaussian anomaly in the cosmic microwave background (CMB) sky detected earlier by Vielva et al. (2004, ApJ, 609, 22), is studied using the data by Planck satellite. The map obtained of the degree of stochasticity (K-map) of CMB for the cold spot, reveals, most clearly in 100 GHz band, a shell-type structure…
The Herschel Planetary Nebula Survey (HerPlaNS). I. Data overview and analysis demonstration with NGC 6781
Nordon, R.; Sahai, R.; Behar, E. +30 more
Context. This is the first of a series of investigations into far-IR characteristics of 11 planetary nebulae (PNe) under the Herschel Space Observatory open time 1 program, Herschel Planetary Nebula Survey (HerPlaNS).
Aims: Using the HerPlaNS data set, we look into the PN energetics and variations of the physical conditions within the target …
Plasma Physical Parameters along Coronal-mass-ejection-driven Shocks. I. Ultraviolet and White-light Observations
Bemporad, A.; Susino, R.; Lapenta, G.
In this work, UV and white-light (WL) coronagraphic data are combined to derive the full set of plasma physical parameters along the front of a shock driven by a coronal mass ejection. Pre-shock plasma density, shock compression ratio, speed, and inclination angle are estimated from WL data, while pre-shock plasma temperature and outflow velocity …
Characteristic distribution and possible roles of waves around the lower hybrid frequency in the magnetotail reconnection region
Xu, Xiaojun; Yuan, Zhigang; Huang, Shiyong +5 more
It has long been suggested that waves around the lower hybrid frequency play a significant role in magnetic reconnection. In this paper we statistically study the distribution and possible roles of waves around lower hybrid frequency based on the wave data recorded by the Cluster spacecraft during 21 magnetotail reconnection events. We find that, …
Radiation-pressure-driven dust waves inside bursting interstellar bubbles
Kaper, L.; Tielens, A. G. G. M.; Berné, O. +3 more
Massive stars drive the evolution of the interstellar medium through their radiative and mechanical energy input. After their birth, they form "bubbles" of hot gas surrounded by a dense shell. Traditionally, the formation of bubbles is explained through the input of a powerful stellar wind, even though direct evidence supporting this scenario is l…