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.

A Pacemaker Current in Dye-Coupled Hilar Interneurons Contributes to the Generation of Giant GABAergic Potentials in Developing Hippocampus

Abstract: The establishment of synaptic connections and their refinement during development require neural activity. Increasing evidence suggests that spontaneous bursts of neural activity within an immature network are mediated by γ-aminobutyric acid via a paradoxical excitatory action. Our data show that in the developing hippocampus such synchronous burst activity is generated in the hilar region by transiently coupled cells. These cells have been identified as neuronal elements because they fire action potentials and they are not positive for the glial fibrillary acidic protein staining. Oscillations in hilar cells are “paced” by a hyperpolarization-activated current, with properties of I h. Coactivated interneurons synchronously release GABA, which via its excitatory action may serve a neurotrophic function during the refinement of hippocampal circuitry.

Supersymmetry breaking at the end of a cascade of Seiberg dualities

Abstract: We study the IR dynamics of the cascading nonconformal quiver theory on $N$ regular and $M$ fractional D3 branes at the tip of the complex cone over the first del Pezzo surface. The horizon of this cone is the irregular Sasaki-Einstein manifold ${Y}^{2,1}$. Our analysis shows that at the end of the cascade supersymmetry is dynamically broken.

A pilot study of the radio-emitting AGN population: the emerging new class of FR0 radio-galaxies

Abstract: We present the results of a pilot JVLA project aimed at studying the bulk of the radio-emitting AGN population, unveiled by the NVSS/FIRST and SDSS surveys.We obtained A-array observations at the JVLA at 1.4, 4.5, and 7.5 GHz for 12 sources of the SDSS/NVSS sample. The radio maps reveal compact unresolved or slightly resolved radio structures on a scale of 1-3 kpc, with only one exception of a FRI/FRII source extended over $\sim$40 kpc. We isolate the radio core component in most of them. The sample splits into two groups. Four sources have small black hole (BH) masses (mostly $\sim$10$^{7}$ M$_{\odot}$) and are hosted by blue galaxies, often showing evidence of a contamination from star formation to their radio emission and associated with radio-quiet AGN. The second group consists in seven radio-loud AGN, which live in red massive ($\sim10^{11}$ M$_{\odot}$) early-type galaxies, with large BH masses ($\gtrsim$10$^{8}$ M$_{\odot}$), and spectroscopically classified as Low Excitation Galaxies, all characteristics typical of FRI radio galaxies. They also lie on the correlation between radio core power and [O III] line luminosity defined by FRIs. However, they are more core dominated (by a factor of $\sim$30) than FRIs and show a deficit of extended radio emission. We dub these sources 'FR0' to emphasize their lack of prominent extended radio emission, the single distinguishing feature with respect to FRIs. The differences in radio properties between FR0s and FRIs might be ascribed to an evolutionary effect, with the FR0 sources undergoing to rapid intermittency that prevents the growth of large scale structures. In our preferred scenario the lack of extended radio emission in FR0s is due to their smaller jet Lorentz $\Gamma$ factor with respect to FRIs, causing possible instabilities and their premature disruption.[abridged]

Planck early results - X. Statistical analysis of Sunyaev-Zeldovich scaling relations for X-ray galaxy clusters

Abstract: All-sky data from the Planck survey and the Meta-Catalogue of X-ray detected Clusters of galaxies (MCXC) are combined to investigate the relationship between the thermal Sunyaev-Zeldovich (SZ) signal and X-ray luminosity. The sample comprises ∼1600 X-ray clusters with redshifts up to ∼1 and spans a wide range in X-ray luminosity. The SZ signal is extracted for each object individually, and the statistical significance of the measurement is maximised by averaging the SZ signal in bins of X-ray luminosity, total mass, or redshift. The SZ signal is detected at very high significance over more than two decades in X-ray luminosity (10 43 erg s −1 L500E(z) −7/3 2 × 10 45 erg s −1 ). The relation between intrinsic SZ signal and X-ray luminosity is investigated and the measured SZ signal is compared to values predicted from X-ray data. Planck measurements and X-ray based predictions are found to be in excellent agreement over the whole explored luminosity range. No significant deviation from standard evolution of the scaling relations is detected. For the first time the intrinsic scatter in the scaling relation between SZ signal and X-ray luminosity is measured and found to be consistent with the one in the luminosity – mass relation from X-ray studies. There is no evidence of any deficit in SZ signal strength in Planck data relative to expectations from the X-ray properties of clusters, underlining the robustness and consistency of our overall view of intra-cluster medium properties.