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Dilip G Banhatti

Publications and source records attributed to Dilip G Banhatti.

4 recordsLinked to original sources
arXiv2017

Getting more out of V/Vm than just the mean

Banhatti (2009) set down the procedure to derive cosmological number density n(z) from the differential distribution p(x) of the fractional luminosity volume relative to the maximum volume, x \equiv V/Vm (0 \leq x \leq 1), using a small sample of 76 quasars for illustrative purposes. This procedure is here applied to a bigger sample of 286 quasars selected from Parkes half-Jansky flat-spectrum survey at 2.7 GHz (Drinkwater et al 1997). The values of n(z) are obtained for 8 values of redshift z from 0 to 3.5. The function n(z) can be interpreted in terms of redshift distribution obtained by integrating the radio luminosity function ρ(P, z) over luminosities P for the survey limiting flux density S0 = 0.5 Jy. Keywords. V/Vm - luminosity-volume - cosmological number density - redshift distribution - luminosity function - quasars [Note: This somewhat modified version was submitted to MNRaS on 14 July 2016. It was (almost) rejected, except if thoroughly revised.]

astro-ph.CO↗
arXiv2009

Effect of errors on arm asymmetry of doubles

Measured values of arm asymmetry parameter x = (theta> - theta<)/(theta> + theta<) of a double have appreciable random errors due to errors in positions of radio peaks & of the optically identified galaxy or quasar. These broaden the monotonic decreasing x-distribution g(x). In addition, finite resolution & blending of complex structure leads to errors in recognizing peaks leading to systematic overestimate of x. Thus both random & systematic errors broaden g(x), & consequently broaden the distribution p(v) of derived hotspot separation speed v, & shift its peak to larger v, since p(v) = -v.g'(v). Keywords: active galaxies - double radio sources - bilateral symmetry - arm asymmetry

astro-ph.GA↗
arXiv2009

Relation between positional & strength asymmetries of double radio sources associated with active galaxies

We bring out the identity between two ways of defining a single parameter to combine positional & strength asymmetries of extended extragalactic double radio sources associated with active galaxies. Thus, (r.s - 1)/[(1 + r).(1 + s)], combining arm ratio r (defined to be <= 1, i.e., shorter to longer arm) & strength ratio s (in the sense closer to farther, so that it may be <, > or = 1), is identical to -(1/2)[(1 - fr)/(1 + fr) - t], where fr is strength ratio defined >= 1 (i.e., stronger to weaker), & t = +/- (Q - 1)/(Q + 1), +/- signs applying respectively to doubles with closer hotspot fainter & those with closer hotspot brighter, while Q is arm ratio defined >= 1. Keywords: active galaxies - double radio sources - bilateral symmetry - arm ratio - flux ratio

astro-ph.GA↗