4,102 research outputs found
AGN mass estimates in large spectroscopic surveys: the effect of host galaxy light
Virial-based methods for estimating active supermassive black hole masses are
now commonly used on extremely large spectroscopic quasar catalogues. Most
spectral analyses, though, do not pay enough attention to a detailed continuum
decomposition. To understand how this affects virial mass estimate results, we
test the influence of host galaxy light on them, along with Balmer continuum
component. A detailed fit with the new spectroscopic analysis software QSFit
demonstrated that the presence or absence of continuum components do not affect
significantly the virial-based results for our sample. Taking or not in
consideration a host galaxy component, instead, affects the emission line
fitting in a more pronounced way at lower redshifts, where in fact we observe
dimmer quasars and more visible host galaxies.Comment: 5 pages, 3 figures, accepted for publication on A&
La comunidad de los otros. A partir de Jean-Luc Nancy
El tema de la "comunidad" es central desde el punto de vista antropológico, ético y filosófico-político. A partir de los años 80 se despliega un debate en el pensamiento francés, y ya en los 90 son autores italianos los que participan en él. La posible-imThe topic of the "community" has a fundamental relevance from the anthropological, ethical and political point of view. Starting from the years 80 in france, and then during the 90 in italy, the debate has been developed in a very vivid manner. The possi
Uncertainty in Multi-Commodity Routing Networks: When does it help?
We study the equilibrium behavior in a multi-commodity selfish routing game
with many types of uncertain users where each user over- or under-estimates
their congestion costs by a multiplicative factor. Surprisingly, we find that
uncertainties in different directions have qualitatively distinct impacts on
equilibria. Namely, contrary to the usual notion that uncertainty increases
inefficiencies, network congestion actually decreases when users over-estimate
their costs. On the other hand, under-estimation of costs leads to increased
congestion. We apply these results to urban transportation networks, where
drivers have different estimates about the cost of congestion. In light of the
dynamic pricing policies aimed at tackling congestion, our results indicate
that users' perception of these prices can significantly impact the policy's
efficacy, and "caution in the face of uncertainty" leads to favorable network
conditions.Comment: Currently under revie
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