deletions | additions       diff --git a/figures/fig_for_inclass_nova1/caption.tex b/figures/fig_for_inclass_nova1/caption.tex  index 64e775e..290b547 100644  --- a/figures/fig_for_inclass_nova1/caption.tex  +++ b/figures/fig_for_inclass_nova1/caption.tex 
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Figure supporting an in-class exercise on understanding image values and signal-to-noise, carried out during the lab period. The exercise itself consisted of the following:  \emph{Consider the attached image of a nova observed with the millimeter telescope CARMA at 96 GHz (Panel A). Histograms of pixel values are shown in Panels B and C (Panel C is just a zoom-in of a region on Panel B); these are just like the histograms you made in DS9's \verb|Scale Parameters|. The pixel values after calibration are expressed as flux density per pixel (units of mJy/pixel). The plotted range ($-2$ to 36 mJy/pixel) includes all pixels in the image.} \noindent 1) \emph{1)  Estimate the average background value ($\bar{S}$) and explain your reasoning.\\ reasoning.}\\  \noindent 2) \emph{2)  Estimate the standard deviation of the background ($\sigma$), and explain your reasoning.\\ reasoning.}\\  \noindent 3) \emph{3)  Estimate the peak flux density of the nova ($S_{\rm max}$), and explain your reasoning.\\ reasoning.}\\  \noindent 4) \emph{4)  Astronomers usually only take detections seriously if they are 5 or more $\sigma$ significant---that is, if the detected source is at least five times brighter than the standard deviation of the background. In other words, the source's peak flux should be $S_{\rm max} > (\bar{S} + 5 \sigma$). Estimate how many sigma the peak flux density of the nova is, and show your reasoning. Would this detection be taken seriously by other astronomers? astronomers?}