International School for Advanced Studies

About: International School for Advanced Studies is a education organization based out in Trieste, Friuli-Venezia Giulia, Italy. It is known for research contribution in the topics: Galaxy & Dark matter. The organization has 3751 authors who have published 13433 publications receiving 588454 citations. The organization is also known as: SISSA & Scuola Internazionale Superiore di Studi Avanzati.

Planck 2015 results - XXVIII. The Planck Catalogue of Galactic cold clumps

Abstract: We present the Planck Catalogue of Galactic Cold Clumps (PGCC), an all-sky catalogue of Galactic cold clump candidates detected by Planck. This catalogue is the full version of the Early Cold Core (ECC) catalogue, which was made available in 2011 with the Early Release Compact Source Catalogue (ERCSC) and which contained 915 high signal-to-noise sources. It is based on the Planck 48-month mission data that are currently being released to the astronomical community. The PGCC catalogue is an observational catalogue consisting exclusively of Galactic cold sources. The three highest Planck bands (857, 454, and 353 GHz) have been combined with IRAS data at 3 THz to perform a multi-frequency detection of sources colder than their local environment. After rejection of possible extragalactic contaminants, the PGCC catalogue contains 13188 Galactic sources spread across the whole sky, i.e., from the Galactic plane to high latitudes, following the spatial distribution of the main molecular cloud complexes. The median temperature of PGCC sources lies between 13 and 14.5 K, depending on the quality of the flux density measurements, with a temperature ranging from 5.8 to 20 K after removing the sources with the top 1% highest temperature estimates. Using seven independent methods, reliable distance estimates have been obtained for 5574 sources, which allows us to derive their physical properties such as their mass, physical size, mean density, and luminosity.The PGCC sources are located mainly in the solar neighbourhood, but also up to a distance of 10.5 kpc in the direction of the Galactic centre, and range from low-mass cores to large molecular clouds. Because of this diversity and because the PGCC catalogue contains sources in very different environments, the catalogue is useful for investigating the evolution from molecular clouds to cores. Finally, it also includes 54 additional sources located in the Small and Large Magellanic Clouds.

All-sky astrophysical component separation with Fast Independent Component Analysis (FastICA)

Abstract: We present a new, fast, algorithm for the separation of astrophysical components superposed in maps of the sky. The algorithm, based on the Independent Component Analysis (ICA) technique, is aimed at recovering both the spatial pattern and the frequency scalings of the emissions from statistically independent astrophysical processes, present along the line-of-sight, from multi-frequency observations, without any a priori assumption on properties of the components to be separated, except that all of them, but at most one, must have non-Gaussian distributions. The analysis starts from very simple toy-models of the sky emission in order to assess the quality of the reconstruction when inputs are well known and controlled. In particular we study the dependence of the results of separation conducted on and off the Galactic plane independently, showing that optimal separation is achieved for sky regions where components are smoothly distributed. Then we move to more realistic applications on simulated observations of the microwave sky with angular resolution and instrumental noise at the mean nominal levels for the Planck satellite. We consider several Planck observation channels containing the most important known diffuse signals: the Cosmic Microwave Background (CMB), Galactic synchrotron, dust and free-free emissions. A method for calibrating the reconstructed maps of each component at each frequency has been devised. The spatial pattern of all the components have been recovered on all scales probed by the instrument. In particular, the CMB angular power spectra is recovered at the percent level up to lmax ≃ 2000. Frequency scalings and normalization have been recovered with better than 1% precision for all the components at frequencies and in sky regions where their signalto-noise ratio > ∼ 1.5; the error increases at ∼ 10% level for signal-to-noise ratios ≃ 1.

Arp 299: A Second Merging System with Two Active Nuclei?

Abstract: Recent BeppoSAX observations of Arp 299, a powerful far-IR merging starburst system composed of IC 694 and NGC 3690, clearly unveiled for the first time in this system the presence of a strongly absorbed active galactic nucleus (AGN). However, the system was not spatially resolved by BeppoSAX. Here we present the analysis of archival Chandra and (for the first time) XMM-Newton observations, which allow us to disentangle the X-ray emission of the two galaxies. The detection of a strong 6.4 keV line in NGC 3690 clearly demonstrates the existence of an AGN in this galaxy, while the presence of a strong 6.7 keV Fe-Kα line in the spectrum of IC 694 suggests that this nucleus might also harbor an AGN. This would be the second discovery of two AGNs in a merging system after NGC 6240.

Analysis of rotation curves in the framework of Rn gravity

Abstract: We present an analysis of a devised sample of Rotation Curves (RCs), aimed atchecking the consequences of a modified f(R) gravity on galactic scales. Originallymotivated by the the dark energy mystery, this theory may serve as a possibility ofexplaining the observed non-Keplerian profiles of galactic RCs in terms of a break-down of the Einstein General Relativity. We show that in general the power-law f(R)version could fit well the observations with reasonable values for the mass modelparameters, encouraging further investigation on R n gravity from both observationaland theoretical points of view.Key words: gravitation – dark matter – galaxies: kinematics and dynamics 1 INTRODUCTIONIt is well-known that the RCs of spiral galaxies show a non-Keplerian circular velocity profile which cannot be explainedby considering a Newtonian gravitational potential gener-ated by the baryonic matter (Persic, Salucci & Stel 1996).Current possible explanation of this controversy includes,among others, the postulate of a new yet not detected stateof matter, the dark matter (Rubin 1983), a phenomeno-logical modification of the Newtonian dynamics (Milgrom1983; Brownstein & Moffat 2006; Sanders & McGaugh 2002;Bekenstein 2007), and higher order gravitational theories(originally devoted to solve the dark energy issue, see e.g.,(Carroll et al. 2004; Capozziello et al. 2004)).The recent theory proposed by Capozziello, Cardone &Troisi 2007 (hereafter CCT), modifies the usual Newtonianpotential generated by baryonic matter in such a way thatthe predicted galaxy kinematics and the observed one havea much better agreement. They consider power-law fourthorder⋆ theories of gravity obtained by replacing in the grav-ity action the Ricci scalar R with a function f(R) ∝ R