Search Publications
Spectral properties and origin of the radio halo in A3562
Finoguenov, A.; Brunetti, G.; Giacintucci, S. +6 more
We present a new detailed multiband study of the merging cluster A3562, in the core of the Shapley Concentration Supercluster. We analyzed new, low frequency radio data performed at 240 MHz, 332 MHz and 610 MHz with the Giant Metrewave Radio Telescope (GMRT). The new GMRT data allowed us to carry out a detailed study of the radio halo at the centr…
Coronal phenomena at the release of solar energetic electron events
Krucker, S.; Klein, K. -L.; Hoang, S. +1 more
We investigate dynamical processes in the solar corona at the release of electrons (~30-500 keV) detected by the Wind/3DP experiment, with the aim to clarify the relationship between coronal acceleration and the escape of electrons to interplanetary space. Energetic electrons and plasma in the corona are traced using radio, EUV and X-ray observati…
Observations of Separator Reconnection to an Emerging Active Region
Longcope, D. W.; Scott, J.; McKenzie, D. E. +1 more
Extreme-ultraviolet (EUV) observations of an emerging active region are used to study separator reconnection in the corona. We identify each EUV loop connecting the emerging polarity to a nearby existing active region over the 41 hr period beginning at emergence onset. Their geometrical resemblance to post-reconnection field lines from a magnetic …
Groundwater-controlled valley networks and the decline of surface runoff on early Mars
Harrison, Keith P.; Grimm, Robert E.
Fluvial erosion on early Mars was dominated by valley networks created through a combination of groundwater processes and surface runoff. A reduced greenhouse effect due to CO2 loss, together with a declining geothermal heat flux, promoted the growth of a cryosphere and a Hesperian hydrologic regime dominated by outflow channel formatio…
High-mass X-ray binaries in the Small Magellanic Cloud: the luminosity function
Gilfanov, M.; Shtykovskiy, P.
We study a population of compact X-ray sources in the Small Magellanic Cloud (SMC) using archival data from the XMM-Newton observatory. The total area of the survey is ~1.5 deg2 with the limiting sensitivity of ~10-14 erg s-1 cm-2, corresponding to a luminosity of ~4.3 × 1033 erg s-1
Hard Spectra of X-ray Pulsars from INTEGRAL Data
Sunyaev, R. A.; Tsygankov, S. S.; Lutovinov, A. A. +1 more
We present spectra for 34 accretion-powers X-ray pulsars and one millisecond pulsar that were within the field of view of the INTEGRAL observatory over two years (December 2002 January 2005) of its in-orbit operation and that were detected by its instruments at a statistically significant level (> 8σ in the energy range 18 60 keV). There are se…
Hubble Space Telescope ultraviolet spectroscopy of blazars: emission-line properties and black hole masses
Pian, E.; Falomo, R.; Treves, A.
The ultraviolet (UV) spectra of 16 blazars (<z>~= 1) from the archives of the Hubble Space Telescope Faint Object Spectrograph have been analysed in order to study in a systematic way the properties of their broad UV emission lines. We find that the luminosities of the most prominent and intense lines, Lyα and CIVλ1549, are similar to those …
Evolution of Field Early-Type Galaxies: The View from GOODS CDFS
Lisker, Thorsten; Mobasher, Bahram; Ferreras, Ignacio +2 more
We explore the evolution of field early-type galaxies in a sample extracted from the ACS images of the southern GOODS field. The galaxies are selected by means of a nonparametric analysis, followed by visual inspection of the candidates with a concentrated surface brightness distribution. We furthermore exclude from the final sample those galaxies…
On the generation of solitary waves observed by Cluster in the near-Earth magnetosheath
Gurnett, D. A.; Balogh, A.; Lakhina, G. S. +13 more
Through case studies involving Cluster waveform observations, solitary waves in the form of bipolar and tripolar pulses have recently been found to be quite abundant in the near-Earth dayside magnetosheath. We expand on the results of those previous studies by examining the distribution of solitary waves from the bow shock to the magnetopause usin…
On the transmission-dominated to reprocessing-dominated spectral state transitions in Seyfert 2 galaxies
Fiore, F.; Guainazzi, M.; Iwasawa, K. +2 more
We present Chandra and XMM-Newton observations of a small sample (11 objects) of optically selected Seyfert 2 galaxies, for which ASCA and BeppoSAX had suggested Compton-thick obscuration of the active galactic nucleus (AGN). The main goal of this study is to estimate the rate of transitions between `transmission-dominated' and `reprocessing-domin…