Why does the Jeans Swindle work?

TY - JOUR

T1 - Why does the Jeans Swindle work?

AU - Falco, Martina

AU - Hansen, Steen Harle

AU - Mamon, G.A.

PY - 2013/5/1

Y1 - 2013/5/1

N2 - When measuring the mass profile of any given cosmological structure through internal kinematics, the distant background density is always ignored. This trick is often referred to as the 'Jeans Swindle'. Without this trick a divergent term from the background density renders the mass profile undefined; however, this trick has no formal justification.We show that when one includes the expansion of the Universe in the Jeans equation, a term appears which exactly cancels the divergent term from the background. We thereby establish a formal justification for using the Jeans Swindle.

AB - When measuring the mass profile of any given cosmological structure through internal kinematics, the distant background density is always ignored. This trick is often referred to as the 'Jeans Swindle'. Without this trick a divergent term from the background density renders the mass profile undefined; however, this trick has no formal justification.We show that when one includes the expansion of the Universe in the Jeans equation, a term appears which exactly cancels the divergent term from the background. We thereby establish a formal justification for using the Jeans Swindle.

U2 - 10.1093/mnrasl/sls051

DO - 10.1093/mnrasl/sls051

M3 - Journal article

SN - 0035-8711

VL - 431

SP - L6-L9

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

IS - 1

ER -