deletions | additions       diff --git a/subsection_Faint_Images_of_the__.tex b/subsection_Faint_Images_of_the__.tex  index cb38a14..ee229b1 100644  --- a/subsection_Faint_Images_of_the__.tex  +++ b/subsection_Faint_Images_of_the__.tex 
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FIRST’s high angular resolution and faint flux density threshold (the rms is 0.15 mJy) come at a price. Some of the flux from extended sources is resolved out. This leads to a systematic underestimation of extended source flux density and a survey threshold that is a function of source size  Moreover ,the higher angular resolution achieved by a more extended antenna configuration comes at a price of lower brightness temperature sensitivity. Brightness temperature ($T_{b}$)  is a measure of the source brightness (or specific intensity - referring to frequency) irrespective of the radiation mechanism. specific intensity: $I_{v} = \frac{dE}{dAd \Omega dt dv}$ W.$m^{-2}$.$sr^{-1}$.$Hz^{-1}$  $T_{b}$ can also be thought of as the temperature of a black-body which radiates at the same specific intensity as an object at some given frequency.  $I_{v} = B_{v}(T_{b})$  where $B_{v}(T)$ is the Planck distribution brightness.  \subsubsection{FIRST and synchrotron radiation - this section is incomplete}  FIRST survey detects synchrotron radiation at the lower radio frequencies in the meter and cm wavelength range as explained in section 1.2.