Possibility of Determining Intergalactic Gas Density by Radio Observations of Flares of Remote Sources

Details Possibility of Determining Intergalactic Gas Density by Radio Observations of Flares of Remote Sources Possibility of Determining Intergalactic Gas Density by Radio Observations of Flares of Remote Sources

Dec 1973

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1973natur.246..415g&link_type=abstract

Nature, Volume 246, Issue 5433, pp. 415 (1973).

Computer Science

9

Scientific paper

DETERMINATION of the mean gas concentration in intergalactic space (N mg) is an important problem which is still far from being solved. One may hope finally to determine the value of N mg in different indirect ways (see, for example, ref. 1). At the same time there is a possibility of finding N mg directly by measuring the radio signal retardation time τ(ν) = t (ν) - t (∞) for a frequency ν, where t (∞) is the time of the arrival of a signal of a rather high frequency. In a completely ionized gas the refractive index n = 1-(e 2 N/2πmν2), the group velocity u = cn and where L is the distance to the signal source assuming (1 - n)<<1 the accuracy of the expressions used is clear (for example, from ref. 2). For our Galaxy, at not very small galactic latitudes, ∫N gdl≡N g L g~(1020 to 1021) cm-2. Therefore at N mg~10-5 cm-3 the product N mg L>N g L g if L>1025 to 1026 cm. Thus, for extragalactic sources at more than 3 to 30 Mpc signal retardation in intergalactic space at N>~10-5 is greater than in the Galaxy and could be measured (I note, as an example, that at N~10-5, ν~3 × 107 Hz and L~1025, the time τ~100 s). To apply this method, which is widely used in the case of pulsars3, there must, however, exist rapidly varying and powerful extragalactic radio emission sources; these have not yet been found.

Affiliated with

Also associated with

No associations

Rating

Possibility of Determining Intergalactic Gas Density by Radio Observations of Flares of Remote Sources does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Possibility of Determining Intergalactic Gas Density by Radio Observations of Flares of Remote Sources, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Possibility of Determining Intergalactic Gas Density by Radio Observations of Flares of Remote Sources will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1312842