Search results for "Shocks"

Indication of a Pulsar Wind Nebula in the Hard X-Ray Emission from SN 1987A

2021

Since the day of its explosion, SN 1987A (SN87A) was closely monitored with the aim to study its evolution and to detect its central compact relic. The detection of neutrinos from the supernova strongly supports the formation of a neutron star (NS). However, the constant and fruitless search for this object has led to different hypotheses on its nature. Up to date, the detection in the ALMA data of a feature somehow compatible with the emission arising from a proto Pulsar Wind Nebula (PWN) is the only hint of the existence of such elusive compact object. Here we tackle this 33-years old issue by analyzing archived observations of SN87A performed Chandra and NuSTAR in different years. We fir…

Models and data analysis tools for the Solar Orbiter mission

2020

All authors: Rouillard, A. P.; Pinto, R. F.; Vourlidas, A.; De Groof, A.; Thompson, W. T.; Bemporad, A.; Dolei, S.; Indurain, M.; Buchlin, E.; Sasso, C.; Spadaro, D.; Dalmasse, K.; Hirzberger, J.; Zouganelis, I.; Strugarek, A.; Brun, A. S.; Alexandre, M.; Berghmans, D.; Raouafi, N. E.; Wiegelmann, T.; Pagano, P.; Arge, C. N.; Nieves-Chinchilla, T.; Lavarra, M.; Poirier, N.; Amari, T.; Aran, A.; Andretta, V.; Antonucci, E.; Anastasiadis, A.; Auchère, F.; Bellot Rubio, L.; Nicula, B.; Bonnin, X.; Bouchemit, M.; Budnik, E.; Caminade, S.; Cecconi, B.; Carlyle, J.; Cernuda, I.; Davila, J. M.; Etesi, L.; Espinosa Lara, F.; Fedorov, A.; Fineschi, S.; Fludra, A.; Génot, V.; Georgoulis, M. K.; Gilbe…

Complex singularities in KdV solutions

2016

In the small dispersion regime, the KdV solution exhibits rapid oscillations in its spatio-temporal dependence. We show that these oscillations are caused by the presence of complex singularities that approach the real axis. We give a numerical estimate of the asymptotic dynamics of the poles.

Gender, Weather Shocks and Welfare: Evidence from Malawi

2017

This paper explores the gender-differentiated effects of weather shocks on households’ welfare in Malawi using panel data aligned with climatic records. Results show that temperature shocks severely affect household welfare, reducing consumption, food consumption and daily caloric intake. The negative welfare effects are more severe for households where land is solely managed by women, a finding that sheds light on the gender-unequal impact of temperature shocks. Our evidence also suggests that women’s vulnerability to temperature shocks is linked to women’s land tenure security, as temperature shocks impact significantly women’s welfare only in patrilineal districts, where statistics show …

Fronts propagating with signal dependent speed in limited diffusion and related Hamilton-Jacobi formulations

2021

We consider a class of limited diffusion equations and explore the formation of diffusion fronts as the result of a combination of diffusive and hyperbolic transport. We analyze a new class of Hamilton-Jacobi equations arising from the convective part of general Fokker-Planck equations ruled by a non-negative diffusion coefficient that depends on the unknown and on the gradient of the unknown. We explore the main features of the solution of the Hamilton-Jacobi equations that contain shocks and propose a suitable numerical scheme that approximates the solution in a consistent way with respect to the solution of the associated Fokker-Planck equation. We analyze three model problems covering d…

Essays on financial stability: an analysis based on NUTS2 and NUTS3 data for Italy

Etude numérique d'équations aux dérivées partielles non linéaires et dispersives

2011

Numerical analysis becomes a powerful resource in the study of partial differential equations (PDEs), allowing to illustrate existing theorems and find conjectures. By using sophisticated methods, questions which seem inaccessible before, like rapid oscillations or blow-up of solutions can be addressed in an approached way. Rapid oscillations in solutions are observed in dispersive PDEs without dissipation where solutions of the corresponding PDEs without dispersion present shocks. To solve numerically these oscillations, the use of efficient methods without using artificial numerical dissipation is necessary, in particular in the study of PDEs in some dimensions, done in this work. As stud…

On critical behaviour in generalized Kadomtsev-Petviashvili equations

2016

International audience; An asymptotic description of the formation of dispersive shock waves in solutions to the generalized Kadomtsev–Petviashvili (KP) equation is conjectured. The asymptotic description based on a multiscales expansion is given in terms of a special solution to an ordinary differential equation of the Painlevé I hierarchy. Several examples are discussed numerically to provide strong evidence for the validity of the conjecture. The numerical study of the long time behaviour of these examples indicates persistence of dispersive shock waves in solutions to the (subcritical) KP equations, while in the supercritical KP equations a blow-up occurs after the formation of the disp…

Cross-listing, price discovery and the informativeness of the trading process

2003

This paper analyzes the price discovery process of securities that trade at multiple markets with trading sessions that totally or partially overlap. Building on Hasbrouck (1995) information share approach, we introduce a methodology that distinguishes two sources of information asymmetries between markets: trade-related and trade-unrelated informative shocks. This approach determines how much of each market?s relative contribution to the price discovery process during the overlapping period is attributable to its own trading activity. We provide empirical evidence on the contribution of the NYSE in the price discovery process of the Spanish cross-listed stocks during the daily two-hour ove…

Regional effects of monetary policy in the U.S.: An empirical re-assessment

2020

Abstract This paper provides an empirical re-assessment of the regional effects of monetary policy in the U.S. We use the narrative series of Romer and Romer (2004) as a measure of monetary policy shocks and impulse response functions estimated directly from a single equation spatial model. We find that monetary policy tightening leads to a persistent decrease in regional real personal income and employment, with asymmetric effects across regions that are magnified by spatial spillovers. The magnitude of the effects depends on the period under analysis and on the direction of the monetary policy shock. We also provide evidence of the existence of the interest rate and the housing market cha…