dispersion measure

dispersion measure

(DM) The number of electrons per unit volume, n e, integrated along the line of sight to a source:
DM = n e dl

where dl is an element of the path. It is the factor that determines, for example, the time delay (i.e. dispersion) between the arrival of radio pulses from a pulsar at two different frequencies. The value of n e in the plane of our Galaxy is typically 0.03 cm–3.

dispersion measure

[də′spər·zhən ‚mezh·ər]
(astronomy)
A quantity that describes the dispersion of a radio signal, proportional to the product of the density of interstellar electrons and the distance to the source.
References in periodicals archive ?
A promising avenue for future research is to analyze how economic policies, production technology, and competitive market environments changed at the industry level over time and determine how such changes correlate with the dispersion measures.
By calculating distance in a second way, using the FRB's dispersion measure, astronomers can get a handle on these cosmological parameters.
One of the reasons the T index is preferred is that, unlike variance and skewness, it is not a mean dependent dispersion measure allowing for comparisons between sectors.
The residuals from those models, "purged" of such effects, are then used to construct price dispersion measures which are regressed on variables related to search costs.
To complete the description of the research method we would like also to list the strengths and weaknesses of the dispersion measure.
They employ measures based on stock prices to create a dispersion measure that reflects structural shifts rather than short-term cyclical fluctuations.
The next investigation is of dispersion measures by gender to see if controlling for work experience, education, and occupation results in a more equal (less disperse) distribution of earnings between men and women.
TABLE 1 CWS for 4 Doctors CWS Dispersion Measure Dr.
In the case of dispersion measures, low compactness can be the result of a riding having to incorporate some geographically distant territory.
Using data on job vacancies, Katherine Abraham and Lawrence Katz [1986] rebut Lilien's conclusion, claiming that the positive coefficient of his dispersion measure picks up the effects of aggregate demand rather than interindustry supply disturbances, and that, therefore, aggregate-demand expansion was the appropriate policy for reducing unemployment in the 1970s.
The sum of job creation and destruction series such as those by Davis and Haltiwanger or those produced using industry data can be used as a cross-sectional dispersion measure.
Although two of the three newly discovered FRBs were discovered relatively close to the galactic plane, their dispersion measures and redshifts suggests an extragalactic origin.