Search Publications
Quasi-ballistic and superdiffusive transport for impulsive solar particle events
Zimbardo, G.; Trotta, E. M.
Context. The propagation of solar energetic particles encompasses a number of transport regimes, which goes from diffusive transport to scatter-free propagation. On the other hand, numerical simulations in the presence of magnetic turbulence, as well as the analysis of propagating particles accelerated at interplanetary shocks, show that superdiff…
The scaling of X-ray variability with luminosity in ultra-luminous X-ray sources
Zezas, A.; Papadakis, I.; Reig, P. +1 more
Aims: We investigate the relationship between the X-ray variability amplitude and X-ray luminosity for a sample of 14 bright ultra-luminous X-ray sources (ULXs) with XMM-Newton/EPIC data, and compare it with the well-established, similar relationship for active galactic nuclei (AGN).
Methods: We computed the normalised excess variance in…
EUV lines observed with EIS/Hinode in a solar prominence
Heinzel, P.; Schmieder, B.; Watanabe, T. +1 more
Context. During a multi-wavelength observation campaign with Hinode and ground-based instruments, a solar prominence was observed for three consecutive days as it crossed the western limb of the Sun in April 2007.
Aims: We report on observations obtained on 26 April 2007 using EIS (Extreme ultraviolet Imaging Spectrometer) on Hinode. They are…
Hinode observations and 3D magnetic structure of an X-ray bright point
Del Zanna, G.; Maclean, R. C.; Alexander, C. E.
Aims: We present complete Hinode Solar Optical Telescope (SOT), X-Ray Telescope (XRT)and EUV Imaging Spectrometer (EIS) observations of an X-ray bright point (XBP) observed on the 10, 11 of October 2007 over its entire lifetime (~12 h). We aim to show how the measured plasma parameters of the XBP change over time and also what kind of similar…
AKARI detections of hot dust in luminous infrared galaxies. Search for dusty active galactic nuclei
Ohyama, Y.; Matsuhara, H.; Oyabu, S. +10 more
Aims: We present a new sample of active galactic nuclei (AGNs) identified using the catalog of the AKARI Mid-infrared (MIR) All-Sky Survey. Our MIR search has the advantage of detecting AGNs that are obscured at optical wavelengths by extinction.
Methods: We first selected AKARI 9 µm excess sources with F(9 µm)/F(KS
XMM-Newton investigations of the Lambda Orionis star-forming region (XILO). I. The young cluster Collinder 69
Bayo, A.; Huélamo, N.; Barrado, D. +6 more
Context. This is the first paper of a series devoted to the Lambda Orionis star-forming region, Orion's Head, from the X-ray perspective. Our final aim is to provide a comprehensive view of this complex region, which includes several distinct associations and dark clouds.
Aims: We aim to uncover the population of the central, young star clust…
Flare occurrence and the spatial distribution of the magnetic helicity flux
Romano, P.; Zuccarello, F.
Context. The accumulation of magnetic helicity via emergence of new magnetic flux and/or shearing photospheric motions is considered an important tool for understanding the processes that lead to eruptive phenomena.
Aims: We highlight a specific aspect of the magnetic helicity accumulation, providing new observational evidence of the role pla…
Photon dominated regions in NGC 3603. [CI] and mid-J CO line emission
Schieder, R.; Ossenkopf, V.; Bertoldi, F. +32 more
Aims: We aim at deriving the excitation conditions of the interstellar gas as well as the local FUV intensities in the molecular cloud surrounding NGC 3603 to get a coherent picture of how the gas is energized by the central stars.
Methods: The NANTEN2-4 m submillimeter antenna is used to map the [CI] 1-0, 2-1 and CO 4-3, 7-6 lines in a …
The outer rings of SN 1987A
Lundqvist, P.; Tziamtzis, A.; Gröningsson, P. +1 more
Aims: We investigate the physical properties and structure of the outer rings of SN 1987A to understand their formation and evolution.
Methods: We used low resolution spectroscopy from VLT/FORS1 and high resolution spectra from VLT/UVES to estimate the physical conditions in the outer rings, using nebular analysis for emission lines such…
Optical multiband surface photometry of a sample of Seyfert galaxies. I. Large-scale morphology and local environment analysis of matched Seyfert and inactive galaxy samples
Mihov, B.; Slavcheva-Mihova, L.
Context. Parallel analysis of the large-scale morphology and local environment of matched active and control galaxy samples plays an important role in studies of the fueling of active galactic nuclei.
Aims: We carry out a detailed morphological characterization of a sample of 35 Seyfert galaxies and a matched sample of inactive galaxies in or…