Search Publications
A Method to Identify and Characterize Binary Candidates—A Study of CoRoT Data
Da Silva, Ronaldo; Silva-Valio, Adriana
The analysis of the CoRoT space mission data was performed aiming to test a method that selects, among the several light curves observed, the transiting systems that likely host a low-mass star orbiting the main target. The method identifies stellar companions by fitting a model to the observed transits. Applying this model, which uses equations s…
Saturn's Radio Emissions and their Relation to Magnetospheric Dynamics
Jackman, C. M.
With the arrival of the Cassini spacecraft at Saturn in July 2004, there have been quasi-continuous observations of Saturn Kilometric Radiation (SKR) emissions. In this paper we review the response of these emissions to dynamics in Saturn's magnetosphere, driven by factors internal and external to the system. We begin by reviewing solar wind data …
A tropospheric signal delay model for radio astronomical observations
Molera Calvés, G.; Duev, D. A.; Pogrebenko, S. V.
In this work, a three-dimensional refraction model is proposed, which allows one to calculate the delay of signal due to the Earth's troposphere—the main source of error limiting the accuracy of modern radio astronomical observations. The method of raytracing through the three-dimensional troposphere (numerical weather model) is used. The results …
The X-ray emission of the WR+O binary WR 79
Sana, Hugues; Nazé, Yaël; Gosset, Eric +1 more
In the framework of our multiwavelength study of the open cluster NGC 6231, we observed the colliding-wind WR+O binary WR 79 at six different epochs with the XMM-Newton observatory. These pointings offer the possibility to study the X-ray spectrum of WR 79 and its possible variability. Our results are briefly discussed and compared with the X-ray …
Use of multi-point analysis and modelling to address cross-scale coupling in space plasmas: Lessons from Cluster
Dunlop, M. W.; Chapman, S.; Shen, C. +10 more
The properties of plasmas (in space) are fundamentally governed by both 'cross-scale' coupling and comparative temporal behaviour operating over the micro-, meso-, and (MHD-) fluid regimes: for example, under conditions of turbulence, during magnetic reconnection and in shocks and other plasma boundaries. These themes map to a number of related an…
Cluster Observations of Plasma Bubbles BBFs and Their Wakes
Walsh, A. P.; Forsyth, C.
Non-Gaussianity and direction-dependent systematics in HST Key Project data
Gupta, Shashikant; Saini, Tarun Deep
Two new statistics, namely Δ? and Δχ, based on the extreme value theory, were derived by Gupta et al. We use these statistics to study the direction dependence in the HST Key Project data, which provides one of the most precise measurements of the Hubble constant. We also study the non-Gaussianity in this data set using these statistics…
A computational study of nonresonant cross-field diffusion of energetic particles due to their interaction with interplanetary magnetic decreases
Costa, E.; Lakhina, G. S.; Tsurutani, B. T. +4 more
We present a new method of calculating cross-field diffusion of charged particles due to their interactions with interplanetary magnetic decreases (MDs) in high heliospheric latitudes. We use a geometric model that evaluates perpendicular diffusion to the ambient magnetic field as a function of particle's gyroradius, MD radius, ratio between field…
A Research on the Evolution of Star Formation Activities of Early-type Galaxies
Zheng, Xian-Zhong; Wang, Fang
The observational investigation of the evolution of the star formation activities of early-type galaxies (ETGs) with redshifts helps us to understand the formation and evolution of this kind of galaxies. Combined with the highresolution images from HST/ACS (Hubble Space Telescope/Advanded Camera for Surveys) of the GEMS (Galaxy Evolution fromMorph…
Variation of high-degree mode frequencies during the declining phase of solar cycle 23
Hill, F.; Jain, K.; Tripathy, S. C.
We investigate the spatial and temporal variation of the high-degree mode frequencies during the declining phase of the solar cycle 23 and the extended minimum between the cycle 23 and 24. We find that the frequency shifts of high-degree modes obtained through the ring-diagram analysis in different phases of the solar cycle are not equally correla…