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Institution

International School for Advanced Studies

EducationTrieste, Friuli-Venezia Giulia, Italy
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.


Papers
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Journal ArticleDOI
TL;DR: In this article, the scalar field is forced to obtain a nontrivial configuration in black hole spacetimes, unless a linear coupling with the Gauss-Bonnet invariant is tuned away.
Abstract: In a recent paper we showed that in shift-symmetric Horndeski theory the scalar field is forced to obtain a nontrivial configuration in black hole spacetimes, unless a linear coupling with the Gauss--Bonnet invariant is tuned away. As a result, black holes generically have hair in this theory. In this companion paper, we first review our argument and discuss it in more detail. We then present actual black hole solutions in the simplest case of a theory with the linear scalar-Gauss--Bonnet coupling. We generate exact solutions numerically for a wide range of values of the coupling and also construct analytic solutions perturbatively in the small-coupling limit. Comparison of the two types of solutions indicates that nonlinear effects that are not captured by the perturbative solution lead to a finite area, as opposed to a central, singularity. Remarkably, black holes have a minimum size, controlled by the length scale associated with the scalar-Gauss--Bonnet coupling. We also compute some phenomenological observables for the numerical solution for a wide range of values of the scalar-Gauss--Bonnet coupling. Deviations from the Schwarzschild geometry are generically very small.

364 citations

Journal ArticleDOI
TL;DR: In this paper, a very faint afterglow is detected superposed onto the host galaxy in the first infrared JHK observations, carried out ~9 hr after the burst, and a rebrightening is detected in all bands, peaking in the R band about 18 rest-frame days after burst.
Abstract: Optical and near-infrared observations of the gamma-ray burst GRB 031203, at z = 0.1055, are reported. A very faint afterglow is detected superposed onto the host galaxy in our first infrared JHK observations, carried out ~9 hr after the burst. Subsequently, a rebrightening is detected in all bands, peaking in the R band about 18 rest-frame days after the burst. The rebrightening closely resembles the light curve of a supernova like SN 1998bw, assuming that the GRB and the SN went off almost simultaneously, but with a somewhat slower evolution. Spectra taken close to the maximum of the rebrightening show extremely broad features as in SN 1998bw. The determination of the absolute magnitude of this SN (SN 2003lw) is difficult owing to the large and uncertain extinction, but likely this event was brighter than SN 1998bw by 0.5 mag in the VRI bands, reaching an absolute magnitude MV = -19.75 ± 0.15.

364 citations

Journal ArticleDOI
Abstract: We use a self-consistent model of galaxy formation and the evolution of the intergalactic medium to study the effects of the reionization of the Universe at high redshift on the properties of satellite galaxies like those seen around the Milky Way. Photoionization suppresses the formation of small galaxies, so that surviving satellites are preferentially those that formed before the Universe reionized. As a result, the number of satellites expected today is about an order of magnitude smaller than the number inferred by identifying satellites with subhaloes of the same circular velocity in high-resolution simulations of the dark matter. The resulting satellite population has an abundance similar to that observed in the Local Group, although the distribution of circular velocities differs somewhat from the available data. We explore many other properties of satellite galaxies, including their gas content, metallicity and star formation rate, and find generally good agreement with available data. Our model predicts the existence of many as yet undetected satellites in the Local Group. We quantify their observability in terms of their apparent magnitude and surface brightness, and also in terms of their constituent stars. A near-complete census of the Milky Way's satellites would require imaging to V≈20 and to a surface brightness fainter than 26 V-band magnitudes per square arcsecond. Satellites with integrated luminosity V=15 should contain of order 100 stars brighter than B=26, with central stellar densities of a few tens per square arcminute. Discovery of a large population of faint satellites would provide a strong test of current models of galaxy formation.

358 citations

Journal ArticleDOI
TL;DR: In this paper, the existence of bound and ground states for nonlinear Schrodinger equations is proved provided the coupling parameter is small and large, respectively, for a class of nonlinear systems of Schroffinger equations.
Abstract: We deal with a class of systems of nonlinear Schrodinger equations, proving the existence of bound and ground states provided the coupling parameter is small and large, respectively.

354 citations

Journal ArticleDOI
TL;DR: The activity-dependent modulation of mRNA targeting and protein accumulation in the dendrites may provide a mechanism for achieving a selective local regulation of the activity of neurotrophins and their receptors, close to their sites of action.
Abstract: The mechanisms underlying the subcellular localization of neurotrophins and their receptors are poorly understood. We show that in cultured hippocampal neurons, the mRNAs for BDNF and TrkB have a somatodendritic localization, and we quantify the extent of their dendritic mRNA localization. In the dendrites the labeling covers on average the proximal 30% of the total dendritic length. On high potassium depolarization, the labeling of BDNF and TrkB mRNA extends on average to 68% of the dendritic length. This increase does not depend on new RNA synthesis, is inhibited by the Na+ channel blocker tetrodotoxin, and involves the activation of glutamate receptors. Extracellular Ca2+, partly flowing through L-type Ca2+ channels, is absolutely required for this process to occur. At the protein level, a brief stimulation of hippocampal neurons with 10 mM KCl leads to a marked increase of BDNF and TrkB immunofluorescence density in the distal portion of dendrites, which also occurs, even if at lower levels, when transport is inhibited by nocodazole. The protein synthesis inhibitor cycloheximide abolishes this increase. The activity-dependent modulation of mRNA targeting and protein accumulation in the dendrites may provide a mechanism for achieving a selective local regulation of the activity of neurotrophins and their receptors, close to their sites of action.

354 citations


Authors

Showing all 3802 results

NameH-indexPapersCitations
Sabino Matarrese155775123278
G. de Zotti154718121249
J. González-Nuevo144500108318
Matt J. Jarvis144106485559
Carlo Baccigalupi137518104722
L. Toffolatti13637695529
Michele Parrinello13363794674
Marzio Nessi129104678641
Luigi Danese12839492073
Lidia Smirnova12794475865
Michele Pinamonti12684669328
David M. Alexander12565260686
Davide Maino12441088117
Dipak Munshi12436584322
Peter Onyisi11469460392
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202322
202279
2021656
2020714
2019712
2018622