44 1052 4ne t 1 2 h 1 e h kt photonsm3 hz1 density

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Unformatted text preview: amount of hot, X- ray emifng gas, and using that gas to determine the mass of a cluster, one can derive the ______ of baryonic to dark maOer 5/14/13 UW, ASTR 323, SP13, Eric Agol ©2013 7 Hydrosta8c equilibrium •  For rich, spherical “relaxed” clusters, it is likely a good approxima8on to treat the hot gas as being in ___________ equilibrium dP d # ρkT & •  In this case: = = % ( !!dr dr $ µmH ' •  Rearranging: M = − kTr %∂ ln ρ + ∂ lnT ( ' * GµmH & ∂ ln r ∂ ln r ) !! € •  So, by measuring the profile of density & temperature of X- ray emifng gas in a cluster, one can diagnose the total _______ mass as a func8on of radius € 5/14/13 UW, ASTR 323, SP13, Eric Agol ©2013 8 X- ray Temperature & Density •  Temperature es8mated from X- ray spectrum: 2 lν / hν = 5.44 × 10−52 ( 4πne )T −1 /2 (hν )−1 e− hν / kT photons!m−3 Hz−1 !! •  Density es8mated from luminosity: 2 Lvol = 1.42 × 10−40 ne T 1 /2Wm−3 !! € •  X- ray telescopes measure the ______ & angular posi8on of every photon – can...
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This document was uploaded on 04/05/2014.

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