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.

Role of the Prefrontal Cortex in the Foreperiod Effect: TMS Evidence for Dual Mechanisms in Temporal Preparation

Abstract: The involvement of right dorsolateral prefrontal cortex (rDLPFC) in explicit temporal processing is well documented. Conversely, the role of this area in implicit temporal processing (e.g., foreperiod [FP] effect) is still poorly understood. The FP effect, usually observed when a range of variable FPs occur randomly and equiprobably, consists of reaction times (RTs) decreasing as the FP increases. Moreover, in such paradigms, RTs increase as a function of the preceding FP (i.e., sequential effects). Patients with lesions of the rDLPFC do not show the typical FP effect. The present study aimed to replicate these results in healthy adults using transcranial magnetic stimulation (TMS) and to further investigate whether any change of sequential effects follows a reduction of the FP effect. The results of 2 experiments (with simple and choice RT tasks, respectively) indicate that the FP effect was significantly reduced after TMS over the rDLPFC, whereas no effect was observed after stimulation of a left contralateral site and the right angular gyrus. Conversely, sequential effects were not influenced by TMS. A dual-process model of the FP phenomena is proposed to interpret the dissociation found between the 2 effects.

Primordial black hole formation in the radiative era: investigation of the critical nature of the collapse

Abstract: Following on after two previous papers discussing the formation of primordial black holes in the early universe, we present here results from an in-depth investigation of the extent to which primordial black hole formation in the radiative era can be considered as an example of the critical collapse phenomenon. We focus on initial supra-horizon-scale perturbations of a type which could have come from inflation, with only a growing component and no decaying component. In order to study perturbations with amplitudes extremely close to the supposed critical limit, we have modified our previous computer code with the introduction of an adaptive mesh refinement scheme. This has allowed us to follow black hole formation from perturbations whose amplitudes are up to eight orders of magnitude closer to the threshold than we could do before. We find that scaling-law behaviour continues down to the smallest black hole masses that we are able to follow and we see no evidence of shock production such as has been reported in some previous studies and which led there to a breaking of the scaling-law behaviour at small black hole masses. We attribute this difference to the different initial conditions used. In addition to the scaling law, we also present other features of the results which are characteristic of critical collapse in this context.

Planck 2013 results. XIII. Galactic CO emission

Abstract: Rotational transition lines of CO play a major role in molecular radio astronomy as a mass tracer and in particular in the study of star formation and Galactic structure. Although a wealth of data exists for the Galactic plane and some well-known molecular clouds, there is no available high sensitivity all-sky survey of CO emission to date. Such all-sky surveys can be constructed using the Planck HFI data because the three lowest CO rotational transition lines at 115, 230 and 345 GHz significantly contribute to the signal of the 100, 217 and 353 GHz HFI channels, respectively. Two different component separation methods are used to extract the CO maps from Planck HFI data. The maps obtained are then compared to one another and to existing external CO surveys. From these quality checks the best CO maps, in terms of signal to noise ratio and/or residual contamination by other emission, are selected. Three different sets of velocity-integrated CO emission maps are produced with different trade-offs between signal-to-noise, angular resolution, and reliability. Maps for the CO J = 1 → 0, J = 2 → 1, and J = 3 → 2 rotational transitions are presented and described in detail. They are shown to be fully compatible with previous surveys of parts of the Galactic plane as well as with undersampled surveys of the high latitude sky. The Planck HFI velocity-integrated CO maps for the J = 1 → 0, J = 2 → 1, and J = 3 →2 rotational transitions provide an unprecedented all-sky CO view of the Galaxy. These maps are also of great interest to monitor potential CO contamination of the Planck studies of the cosmological microwave background.

Quasar Luminosity Functions from Joint Evolution of Black Holes and Host Galaxies

Abstract: We show that our previously proposed antihierarchical baryon collapse scenario for the joint evolution of black holes and host galaxies predicts quasar luminosity functions at redshifts 1.5 z 6 and local properties in nice agreement with observations. In our model the quasar activity marks and originates the transition between an earlier phase of violent and heavily dust-enshrouded starburst activity promoting rapid black hole growth, and a later phase of almost passive evolution; the former is traced by the submillimeter-selected sources, while the latter accounts for the high number density of massive galaxies at substantial redshifts z 1.5, the population of extremely red objects, and the properties of local elliptical galaxies.