Search Publications
Chromospheric activity in sunspot light bridges
Louis, R. E.
High-resolution filtergrams from Hinode were used to analyse the nature of chromospheric activity over a set of five sunspot light bridges. The broad-band Ca II H filtergrams depict a variety of phenomena which include large arc-shaped brightenings, bright patches, and small-scale jets. These strong brightenings are recurrent over a duration of se…
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…
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…
Variability of the X-ray broad iron spectral features in active galactic nuclei and black-hole binaries
Tsujimoto, M.; Ebisawa, K.; Inoue, H. +1 more
The ``broad iron spectral features'' are often seen in X-ray spectra of active galactic nuclei (AGN) and black-hole binaries (BHB). These features may be explained either by the ``relativistic disc reflection'' scenario or the ``partial covering'' scenario: It is hardly possible to determine which model is valid from time-averaged spectral analysi…
The Gaia spectrophotometric standard stars survey: II. Instrumental effects of six ground-based observing campaigns
Jordi, C.; Figueras, F.; Marinoni, S. +16 more
The Gaia SpectroPhotometric Standard Stars (SPSS) survey started in 2006, was awarded almost 450 observing nights and accumulated almost 100 000 raw data frames with both photometric and spectroscopic observations. Such large observational effort requires careful, homogeneous, and automatic data reduction and quality control procedures. In this pa…
Geometric characterization of the Arjuna orbital domain
de la Fuente Marcos, R.; de la Fuente Marcos, C.
Arjuna-type orbits are characterized by being Earth-like, having both low-eccentricity and low-inclination. Objects following these trajectories experience repeated trappings in the 1:1 commensurability with the Earth and can become temporary Trojans, horseshoe librators, quasi-satellites, and even transient natural satellites. Here, we review wha…
Intrinsic colour indices of Be stars obtained from 2MASS photometry
Wegner, W.
This paper is based on 2MASS photometry (JHK_s magnitudes) of 1172 Be stars. The observed mean intrinsic colours have been derived with aid of two-colour diagrams for Be stars of luminosity classes Ie-IIe, IIIe and IVe-Ve. The obtained results are the first determinations of their intrinsic colours in the astronomical literature. The smoothed infr…
CoRoT data reduction by example
Weingrill, J.
Data reduction techniques published so far for the CoRoT N2 data product were targeted primarily on the detection of extrasolar planets. Since the whole dataset has been released, specific algorithms are required to process the lightcurves from CoRoT correctly. Though only unflagged datapoints must be chosen for scientific processing, some flags m…
3XMM J185246.6+003317 as transient neutron star
Neuhäuser, R.; Hohle, M. M.; Hambaryan, V. +2 more
We performed an X-ray timing and spectral analysis of the variable source 3XMM J185246.6+003317 to investigate its physical nature. The data from all observations of 3XMM J185246.6+003317 conducted by XMM-Newton EPIC MOS1 and MOS2 with the same instrumental setup in 2004-2009 were reprocessed to form a homogenous data set of solar barycenter corre…