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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 paper, the authors introduce a new analytical fitting formula for the power spectrum, which is simple yet flexible enough to reproduce the clustering signal of large classes of non-thermal dark matter models, which are not at all adequately described by the oversimplified notion of WDM.
Abstract: Structure formation at small cosmological scales provides an important frontier for dark matter (DM) research. Scenarios with small DM particle masses, large momenta or hidden interactions tend to suppress the gravitational clustering at small scales. The details of this suppression depend on the DM particle nature, allowing for a direct link between DM models and astrophysical observations. However, most of the astrophysical constraints obtained so far refer to a very specific shape of the power suppression, corresponding to thermal warm dark matter (WDM), i.e., candidates with a Fermi-Dirac or Bose-Einstein momentum distribution. In this work we introduce a new analytical fitting formula for the power spectrum, which is simple yet flexible enough to reproduce the clustering signal of large classes of non-thermal DM models, which are not at all adequately described by the oversimplified notion of WDM. We show that the formula is able to fully cover the parameter space of sterile neutrinos (whether resonantly produced or from particle decay), mixed cold and warm models, fuzzy dark matter, as well as other models suggested by effective theory of structure formation (ETHOS). Based on this fitting formula, we perform a large suite of N-body simulations and we extract important nonlinear statistics, such as the matter power spectrum and the halo mass function. Finally, we present first preliminary astrophysical constraints, based on linear theory, from both the number of Milky Way satellites and the Lyman-$\alpha$ forest. This paper is a first step towards a general and comprehensive modeling of small-scale departures from the standard cold DM model.

152 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the dependence of the local space density of spiral galaxies on luminosity, scale size, and surface brightness, and they derived bivariate space density distributions in these quantities from a sample of about 1000 Sb-Sdm spiral galaxies, corrected for selection effects in luminosity.
Abstract: We investigate the dependence of the local space density of spiral galaxies on luminosity, scale size, and surface brightness. We derive bivariate space density distributions in these quantities from a sample of about 1000 Sb-Sdm spiral galaxies, corrected for selection effects in luminosity and surface brightness. The structural parameters of the galaxies were corrected for internal extinction using a description depending on galaxy surface brightness. We find that the bivariate space density distribution of spiral galaxies in the (luminosity, scale size)-plane is well described by a Schechter luminosity function in the luminosity dimension and a log-normal scale-size distribution at a given luminosity. This parameterization of the scale-size distribution was motivated by a simple model for the formation of disks within dark matter halos, with halos acquiring their angular momenta through tidal torques from neighboring objects and the disk specific angular momentum being proportional to that of the parent halo. However, the fractional width of the scale-size distribution at a given luminosity is narrower than what one would expect from using the distribution of angular momenta of halos measured in N-body simulations of hierarchical clustering. We present several possible explanations for the narrowness of the observed distribution. Using our bivariate distribution, we find that determinations of the local luminosity function of spiral galaxies should not be strongly affected by the bias against low surface brightness galaxies, even when the galaxies are selected from photographic plates. This may not be true for studies at high redshift, where (1 + z)4 surface brightness dimming would cause a significant selection bias against lower surface brightness galaxies, if the galaxy population did not evolve with redshift.

151 citations

Journal ArticleDOI
Peter A. R. Ade1, Nabila Aghanim2, M. Arnaud3, M. Ashdown4  +231 moreInstitutions (58)
TL;DR: In this paper, the authors investigated the source of the millimetre excess in the spectral energy distribution of the Large Magellanic Cloud (LMC) and Small Magellan Cloud (SMC) using the Planck data.
Abstract: The integrated spectral energy distributions (SED) of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) appear significantly flatter than expected from dust models based on their far-infrared and radio emission. The still unexplained origin of this millimetre excess is investigated here using the Planck data. The integrated SED of the two galaxies before subtraction of the foreground (Milky Way) and background (CMB fluctuations) emission are in good agreement with previous determinations, confirming the presence of the millimetre excess. In the context of this preliminary analysis we do not propose a full multi-component fitting of the data, but instead subtract contributions unrelated to the galaxies and to dust emission. The background CMB contribution is subtracted using an internal linear combination (ILC) method performed locally around the galaxies. The foreground emission from the Milky Way is subtracted as a Galactic Hi template, and the dust emissivity is derived in a region surrounding the two galaxies and dominated by Milky Way emission. After subtraction, the remaining emission of both galaxies correlates closely with the atomic and molecular gas emission of the LMC and SMC. The millimetre excess in the LMC can be explained by CMB fluctuations, but a significant excess is still present in the SMC SED. The Planck and IRAS–IRIS data at 100 μm are combined to produce thermal dust temperature and optical depth maps of the two galaxies. The LMC temperature map shows the presence of a warm inner arm already found with the Spitzer data, but which also shows the existence of a previously unidentified cold outer arm. Several cold regions are found along this arm, some of which are associated with known molecular clouds. The dust optical depth maps are used to constrain the thermal dust emissivity power-law index (β). The average spectral index is found to be consistent with β = 1.5 and β = 1.2 below 500μm for the LMC and SMC respectively, significantly flatter than the values observed in the Milky Way. Also, there is evidence in the SMC of a further flattening of the SED in the sub-mm, unlike for the LMC where the SED remains consistent with β = 1.5. The spatial distribution of the millimetre dustexcess in the SMC follows the gas and thermal dust distribution. Different models are explored in order to fit the dust emission in the SMC. It is concluded that the millimetre excess is unlikely to be caused by very cold dust emission and that it could be due to a combination of spinning dust emission and thermal dust emission by more amorphous dust grains than those present in our Galaxy.

151 citations

Journal ArticleDOI
TL;DR: In this article, the authors consider the problem of exact integration of the T-overline T -deformation of two dimensional quantum field theories, as well as some higher dimensional extensions in the form of det-T -deformations.
Abstract: We consider the problem of exact integration of the $$ T\overline{T} $$ -deformation of two dimensional quantum field theories, as well as some higher dimensional extensions in the form of det T -deformations. When the action can be shown to only depend algebraically on the background metric the solution of the deformation equation on the Lagrangian can be given in closed form in terms of solutions of the (extended) Burgers’ equation. We present such examples in two and higher dimensions.

151 citations

Journal ArticleDOI
TL;DR: In this article, a generalized hydrodynamic description applies, according to which the system can locally be represented by space-and time-dependent stationary states, where magnetization displays an unusual behavior: depending on the initial state, its profile may exhibit abrupt jumps that can not be predicted directly from the standard hydrodynamics equations.
Abstract: We consider the nonequilibrium protocol where two semi-infinite gapped XXZ chains, initially prepared in different equilibrium states, are suddenly joined together At large times, a generalized hydrodynamic description applies, according to which the system can locally be represented by space- and time-dependent stationary states The magnetization displays an unusual behavior: depending on the initial state, its profile may exhibit abrupt jumps that can not be predicted directly from the standard hydrodynamic equations and which signal nonballistic spin transport We ascribe this phenomenon to the structure of the local conservation laws and make a prediction for the exact location of the jumps We find that the jumps propagate at the velocities of the heaviest quasiparticles By means of time-dependent density matrix renormalization group simulations we show that our theory yields a complete description of the long-time steady profiles of conserved charges, currents, and local correlations

151 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