1,721,087 research outputs found
The extragalactic sources at mm wavelengths and their role as CMB foregrounds
Full text linkThe thesis is divided into three main parts. In the first part we have discussed the characterization of the radio source emission in the high radio frequency band. The second part has been devoted to investigating the Sunyaev-Zel’dovich effect focussing on its observability and on theoretical predictions for proto-galaxies. Finally, in the third part we have dealt with radio sources as a CMB foreground, with special reference to the Planck mission
The polarimetric multi-frequency radio sources properties
Full text linkThe polarization properties of extragalactic radio sources at frequencies higher than 20GHz are still poorly constrained. However, their characterization would provide invaluable information about the physics of the emission processes and is crucial to estimate their contamination as foregrounds of the polarized Cosmic Microwave Background (CMB) angular power spectrum on scales 30arcmin. In this contribution, after summarizing the state-of-the-art of polarimetric observations in the millimetric wavelength bands, we present our observations of a complete sample of 53 sources with S20GHz > 200mJy carried out with the Australia Telescope Compact Array (ACTA) between 5.5 and 38GHz. The analysis clearly shows that polarization properties cannot be simply inferred from total intensity ones, as the spectral behaviors of the two signals are typically different
Advanced European Network of E-infrastructures for Astronomy with the SKA
Full text linkHere, I present the AENEAS (Advanced European Network of E-infrastructures for Astronomy with the SKA) project has been funded in the Horizon 2020 Work Programme call “Research and Innovation Actions for International Co-operation on high-end e-infrastructure requirements” supporting the Square Kilometre Array (SKA).
INAF is contributing to all the AENEAS working packages and leading the WP5 - Access and Knowledge Creation
(WP leader M. Massardi IRA-ARC), participants from IRA (Brand, Nanni, Venturi) ,OACT(Becciani, Costa, Umana),
OATS (Smareglia, Knapic, Taffoni
User interaction models towards the SKA
No full textSKA is an evolutionary jump, not only in data size, but also in the astronomical user approach to the facility. User support upport and efficient interfaces allow a broader community to access the resources offered by SKA and maximize the telescope scientific outcome. The ALMA experience paves the ways but gaps remain in the system and user approach. AENEAS WP5 is focused on the interface between a distributed European SKA Regional Centre (ESRC) and a distributed body of end users whose goal is the exploitation of SKA data for knowledge creation. WP5 therefore studied the design of “user interaction models” that could be implemented for the ESRC. In the presentation we summarize the ingredients define a recommended user interaction scheme for the SRC and the identify some actions to build it.</p
The ARI-L development project
No full textThe Additional Representative Images for Legacy (ARI-L, PI: Massardi) project aims to increase the legacy value of the ALMA Science Archive (ASA) by bringing the reduction level of ALMA data from Cycles 2-4 close to the level of the more recent Cycles processed with the ALMA Imaging Pipeline.
The project has been recently approved by ESO and JAO and will soon start producing and ingesting into the ASA a uniform set of full data cubes and continuum images covering at least 70\% of the data from Cycles 2-4. These cubes will complement the much smaller QA2-generated image products, which cover only a small fraction (< 10\%) of the observed data for those cycles.
I will present the project rationale and its operational plan
The ALMA Re-Imaging (ARI) development study
No full textHere it is presented the ALMA Re-Imaging (ARI) development study which the IT ARC node is leading
Multi-frequency polarimetric study of a complete sample of extragalactic radio sources: radio source populations and cosmological perspectives
Full text linkThe high-frequency (> 20 GHz), bright flux density (> 200 mJy) radio population is dominated by blazars, i.e. compact Doppler-boosted objects, whose emission arises from knot-like synchrotron structures along the relativistic jet. Their polarization properties was so far poorly constrained at high frequency and results in literature are typically biased.
Extending the characterization of polarization properties of radio sources to high frequencies provides invaluable information about magnetic fields and plasma in the inner and unresolved regions of relativistic jets. Furthermore, extragalactic radio sources are an important contaminant for the angular power spectrum of CMB (Cosmic Microwave Background) at scales smaller than 30 arcmin, up to 100 GHz: their polarimetry is crucial to search for primordial B-modes, the footprint of inflation.
We present the analysis of high sensitivity (rms ~ 0.6 mJy) multi-frequency and multi-epoch polarimetric observations of a complete sample of 104 compact extragalactic radio sources drawn from the faint (> 200 mJy at 20 GHz in total intensity) Planck-ATCA Coeval Observations (PACO) catalogue, performed with the Australia Telescope Compact Array (ATCA) at 7 frequencies, between 2.1 and 38 GHz. We found that polarization spectra of single sources cannot be simply inferred from total intensity ones, as different synchrotron components dominate the different emissions. We distinguish six spectral categories finding different behaviours in polarization fractions and position angles. Multi-epoch variability analysis (from 1.5 up to 10 yr time lags) is also presented.
ALMA (Atacama Large Millimetre and sub-millimetre Array) observations extends the analysis up to 100 GHz for a (complete) sub-sample of 32 objects. We still find synchrotron signal at these frequencies with no sign of thermal or dust emissions.
We compute number counts in polarization at 20 and 100 GHz to a deeper level than available so far and provide forecasts for forthcoming CMB experiments
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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