Search Publications
Star formation in the hosts of GHz peaked spectrum and compact steep spectrum radio galaxies
O'Dea, C. P.; Labiano, A.; Baum, S. A. +2 more
Aims:We are searching for star formation regions in the hosts of potentially young radio galaxies (gigahertz peaked spectrum and compact steep spectrum sources).
Methods: We used near-UV imaging with the Hubble Space Telescope Advanced Camera for Surveys.
Results: We find near-UV light could be the product of recent star formation in five …
An X-ray and optical study of the ultracompact X-ray binary A 1246-58
Verbunt, F.; in't Zand, J. J. M.; Méndez, M. +4 more
Results are discussed of an X-ray and optical observation campaign of the low-mass X-ray binary A 1246-58 performed with instruments on Satellite per Astronomia X (“BeppoSAX”), the Rossi X-ray Timing Explorer (RXTE), the X-ray Multi-mirror Mission (“XMM-Newton”), the Swift mission, and the Very Large Telescope. Spectra and flux time histories are …
Electron-impact excitation of Be-like Mg
Del Zanna, G.; Badnell, N. R.; Rozum, I.
We present an R-matrix calculation of electron-impact excitation of Be-like Mg. The calculation is similar to that one presented for Be-like Fe by Chidichimo et al. (2005, A&A, 430, 331), and was done with the intermediate-coupling frame transformation method and including a total of 98 fine-structure levels, up to n=4. We find significant dif…
Swift observations of IBL and LBL objects
Tosti, G.; Giommi, P.; Nesci, R. +5 more
Context: BL Lacs are an enigmatic class of active galactic nuclei (AGNs), characterized by the non-thermal continuum typically attributed to synchrotron and inverse Compton emission. Depending on the frequency location of the maxima of these components, they are subdivided into three subclasses LBLs, IBLs, and HBLs. We present the results of a set…
ACS imaging of star clusters in M 51. II. The luminosity function and mass function across the disk
Larsen, S. S.; Gieles, M.; Lamers, H. J. G. L. M. +2 more
Context: Whether or not there exists a physical upper mass limit for star clusters is as yet unclear. For small cluster samples the mass function may not be sampled all the way to the truncation, if there is one. Data for the rich cluster population in the interacting galaxy M 51 enables us to investigate this in more detail.
Aims: Using HST/A…
Observational evidence for return currents in solar flare loops
Benz, A. O.; Battaglia, M.
Context: The common flare scenario comprises an acceleration site in the corona and particle transport to the chromosphere. Using satellites available to date it has become possible to distinguish between the two processes of acceleration and transport, and study the particle propagation in flare loops in detail, as well as complete comparisons wi…
The physical structure of the point-symmetric and quadrupolar planetary nebula NGC 6309
Torrelles, J. M.; Miranda, L. F.; Vázquez, R. +4 more
Aims:We analyse the point-symmetric planetary nebula
Methods: We used VLA-D λ3.6-cm continuum, ground-based, and HST-archive imaging as well as long slit high-…
INTEGRAL and Swift/XRT observations of the SFXT IGR J16479-4514: from quiescence to fast flaring activity
Masetti, N.; Bird, A. J.; Ubertini, P. +6 more
Context: The fast X-ray transient IGR J16479-4514 is known to display flares typically lasting a few hours. Recently, its counterpart has been identified with a supergiant star, therefore the source can be classified as a member of the newly discovered class of Supergiant Fast X-ray Transients (SFXTs); specifically, it is the one with the highest …
Abundance variations and first ionization potential trends during large stellar flares
Nordon, R.; Behar, E.
Context: In the solar corona, elements of low first ionization potential (FIP ⪉ 10 eV) are enriched relative to their abundances in the photosphere, while high-FIP abundances remain unchanged. This was labeled as the Solar FIP effect. High-resolution X-ray spectroscopy has revealed that active stellar coronae show an opposite effect, which was lab…
The properties of penumbral microjets inclination
Katsukawa, Y.; Jurčák, J.
Aims: We investigate the dependence of penumbral microjets inclination on the position within penumbra.
Methods: The high cadence observations taken on 10 November 2006 with the Hinode satellite through the Ca II H and G-band filters were analysed to determine the inclination of penumbral microjets. The results were then compared with the incl…