منابع مشابه
Time Delays in Cosmic Ray Propagation
Cosmic Rays (CR) travel at speeds essentially indistinguishable from the speed of light. However whilst travelling through magnetic fields, both regular and turbulent, they are delayed behind the light since they are usually charged particles and their paths are not linear. Those delays can be so long that they are an impediment to correctly identifying sources which may be variable in time. Fu...
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An $(n, r)$-arc is a set of $n$ points of a projective plane such that some $r$, but no $r+1$ of them, are collinear. The maximum size of an $(n, r)$-arc in $PG(2, q)$ is denoted by $m_r(2,q)$. In this paper we present a new $(184,12)$-arc in PG$(2,17),$ a new $(244,14)$-arc and a new $(267,15$)-arc in $PG(2,19).$
متن کاملAnalytic Time Delays and H0 Estimates for Gravitational Lenses
We study gravitational lens time delays for a general family of lensing potentials, which includes the popular singular isothermal elliptical potential and singular isothermal elliptical density distribution but allows general angular structure. Using a novel approach, we show that the time delay can be cast in a very simple form, depending only on the observed image positions. Including an ext...
متن کاملKernel regression estimates of time delays between gravitationally lensed fluxes
Strongly lensed variable quasars can serve as precise cosmological probes, provided that time delays between the image fluxes can be accurately measured. A number of methods have been proposed to address this problem. In this paper, we explore in detail a new approach based on kernel regression estimates, which is able to estimate a single time delay given several datasets for the same quasar. ...
متن کاملComparing Time-Use Estimates of Two Different Time Diary Methods
Objectives: Time-use has become an important field of research in social and medical sciences. Time diary is the most popular method for measuring time-use that has 2 different methods of administration including yesterday and tomorrow diary. The present study aimed to compare these methods of measuring time-use. Methods: This cross-sectional comparative study was conducted on 256 under 5-yea...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society: Letters
سال: 2009
ISSN: 1745-3925,1745-3933
DOI: 10.1111/j.1745-3933.2009.00770.x