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Photometric redshifts with the quasi Newton algorithm (MLPQNA) Results in the PHAT1 contest
Brescia, M.; Cavuoti, S.; Mercurio, A. +1 more
Context. Since the advent of modern multiband digital sky surveys, photometric redshifts (photo-z's) have become relevant if not crucial to many fields of observational cosmology, such as the characterization of cosmic structures and the weak and strong lensing.
Aims: We describe an application to an astrophysical context, namely the evaluati…
The Impact of Polarized Extragalactic Radio Sources on the Detection of CMB Anisotropies in Polarization
Tucci, Marco; Toffolatti, Luigi
Recent polarimetric surveys of extragalactic radio sources (ERS) at frequencies \nu>1GHz are reviewed. By exploiting all the most relevant data on the polarized emission of ERS we study the frequency dependence of polarization properties of ERS between 1.4 and 86GHz. For flat-spectrum sources the median (mean) fractional polarization increases …
The Sub-mJy Radio Population of the E-CDFS: Optical and Infrared Counterpart Identification
Brandt, W. N.; Tozzi, P.; Balestra, I. +9 more
We study a sample of 883 sources detected in a deep Very Large Array survey at 1.4 GHz in the Extended Chandra Deep Field South. This paper focuses on the identification of their optical and infrared (IR) counterparts. We use a likelihood-ratio technique that is particularly useful when dealing with deep optical images to minimize the number of sp…
Wave-particle interaction in a plasmaspheric plume observed by a Cluster satellite
Yuan, Zhigang; Zhou, Meng; Deng, Xiaohua +5 more
The wave-particle interaction is a possible candidate for the energy coupling between the ring current and plasmaspheric plumes. In this paper, we present wave and particle observations made by the Cluster C1 satellite in a plasmaspheric plume in the recovery phase of the geomagnetic storm on 18 July 2005. Cluster C1 simultaneously observed Pc1-2 …
Magnetosphere-atmosphere coupling at Saturn: 1 - Response of thermosphere and ionosphere to steady state polar forcing
Galand, M.; Moore, L.; Müller-Wodarg, I. C. F. +2 more
We present comprehensive calculations of the steady state response of Saturn’s coupled thermosphere-ionosphere to forcing by solar radiation, magnetospheric energetic electron precipitation and high latitude electric fields caused by sub-corotation of magnetospheric plasma. Significant additions to the physical processes calculated in our Saturn T…
A new technique to efficiently select Compton-thick AGN
Caccianiga, A.; Severgnini, P.; Della Ceca, R.
Aims: We present a new efficient diagnostic method, based on mid-infrared and X-ray data, to select local (z < 0.1) Compton-thick AGN with the aim of estimating their surface and space density.
Methods: We define a region in the X-ray-to-mid-IR [F(2-12 keV)/F25ν25] vs. X-ray color (HR) plane associated to Compton…
Spectral monitoring of RX J1856.5-3754 with XMM-Newton. Analysis of EPIC-pn data
Haberl, F.; Tiengo, A.; Mereghetti, S. +3 more
Using a large set of XMM-Newton observations, we searched for the long-term spectral and flux variability of the isolated neutron star RX J1856.5-3754 in the time interval from April 2002 to October 2011. This is the brightest and most extensively observed source of a small group of nearby, thermally emitting isolated neutron stars, of which at le…
Insights on the X-ray weak quasar phenomenon from XMM-Newton monitoring of PHL 1092
Brandt, W. N.; Fabian, A. C.; Boller, Th. +3 more
PHL 1092 is a z ∼ 0.4 high-luminosity counterpart of the class of Narrow-Line Seyfert 1 galaxies. In 2008, PHL 1092 was found to be in a remarkably low X-ray flux state during an XMM-Newton observation. Its 2 keV flux density had dropped by a factor of ∼260 with respect to a previous observation performed 4.5 yr earlier. The ultraviolet (UV) flux …
The evolution of Venus: Present state of knowledge and future exploration
Leblanc, François; Chassefière, Eric; Marty, Bernard +1 more
A detailed characterization of the formation and evolution of Venus is a key link to the study of terrestrial planets, and to their divergent evolutions. While Earth and to a lesser extent Mars (thanks to the analysis of SNC meteorites) are extensively studied in a comparative planetology context, the history of the most Earth-like planet of the S…
Dark Matter Search Using XMM-Newton Observations of Willman 1
Loewenstein, Michael; Kusenko, Alexander
We report the results of a search for an emission line from radiatively decaying dark matter in the ultra-faint dwarf spheroidal galaxy Willman 1 based on analysis of spectra extracted from XMM-Newton X-ray Observatory data. The observation follows up our analysis of Chandra data of Willman 1 that resulted in line flux upper limits over the Chandr…