Search Publications
Measuring key X-ray parameters from simulated spectra of Seyfert galaxies
Gallo, L. C.; Bonson, K.
Supermassive black hole (SMBH) accretion is an important topic of astrophysical research for a variety of fields. However, literature shows that precisely modelling the X-ray reflection component of an accretion disk around a SMBH is challenging. We test how reliably we can measure key active galactic nuclei (AGN) X-ray reflection parameters by si…
Determination of the shape and orientation of nonlinear magnetic structures measured by Cluster spacecraft in the vicinity of the bow shock
Grzesiak, Marcin; Przepiórka, Dorota; Strumik, Marek +1 more
We present a new method of determination of the size and the orientation of nonlinear electromagnetic structures observed in space plasmas. The method is based on the analysis of covariance matrix of gradients of fields estimated from multipoint spacecraft measurements. It does not make use of Taylor hypothesis and gives fully three-dimensional es…
The Effects of Spatial Smoothing on Solar Magnetic Helicity Parameters and the Hemispheric Helicity Sign Rule
Petrie, Gordon; Ocker, Stella Koch
The hemispheric preference for negative/positive helicity to occur in the northern/southern solar hemisphere provides clues to the causes of twisted, flaring magnetic fields. Previous studies on the hemisphere rule may have been affected by seeing from atmospheric turbulence. Using Hinode/SOT-SP data spanning 2006-2013, we studied the effects of t…
Identifying and Tracking Solar Photospheric Bright Points Based on Three-dimensional Segmentation Technology
Feng, S.; Ji, K. F.; Xiong, J. P. +3 more
Photospheric bright points (PBPs) are tiny and short-lived phenomena which can be seen within dark inter-granular lanes. In this paper, we develop a new method to identify and track the PBPs in the three-dimensional data cube. Different from the previous way such as Detection-Before-Tracking, this method is based on the Tracking-While-Detection. U…
Discovery of two new fast X-ray transients with INTEGRAL: IGR J03346+4414 and IGR J20344+3913
Sidoli, L.; Bird, A. J.; Paizis, A. +1 more
We report on the discovery of two fast X-ray transients (FXTs) from analysis of archival INTEGRAL data. Both are characterized by a remarkable hard X-ray activity above 20 keV, in terms of duration (∼15 and 30 min, respectively), peak flux (∼10-9 erg cm-2 s-1) and dynamic range (∼2400 and 1360, respectively). Swift…
Mars launch to test collaboration between Europe and Russia
Gibney, Elizabeth
Joint ExoMars mission launches lander and orbiter — a rover is planned for 2018.
How a Cartoon Series Helped the Public Care about Rosetta and Philae
Bauer, M.; McCaughrean, M.; O'Flaherty, K. S. +5 more
Once upon a time... is a series of short cartoons that have been developed as part of the European Space Agency's communication campaign to raise awareness about the Rosetta mission. The series features two anthropomorphic characters depicting the Rosetta orbiter and Philae lander, introducing the mission story, goals and milestones with a fairy- …
Multi-spectral observations of flares
Zuccarello, F.
Observations show that during solar flares radiation can be emitted across the entire electromagnetic spectrum, spanning from gamma rays to radio waves. These emissions, related to the conversion of magnetic energy into other forms of energy (kinetic, thermal, waves) through magnetic reconnection, are due to different physical processes that can o…
Broadband X-ray study of the galactic black hole binary 4U 1630-47 with Suzaku
Done, C.; Hori, T.; Shidatsu, M. +4 more
We present the results from our Suzaku observations of the Galactic black hole binary 4U 1630-47. 4U 1630-47 was observed in the very high state (VHS) during the 2012 September-October outburst. The inner disk appears slightly truncated by comparison with a previous high/soft state (HSS) of this source, even by taking into account energetic coupli…
Effect of the meridional velocity gradient on the anisotropy of turbulence in the solar wind
Erofeev, D. V.
In this paper, the heliolatitude dependence of the anisotropy of hourly interplanetary magnetic field fluctuations under conditions characteristic of low solar activity is studied. Measurements carried out by the Ulysses spacecraft in 1992–1994 and 1995–1997 are analyzed. It is found that the minimum fluctuation variance axis has a significant til…