Open AccessCombining rotation curves and gravitational lensing: how to measure the equation of state of dark matter in the galactic halo
Author(s) -
Faber Tristan,
Visser Matt
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.10845.x
Subject(s) - physics , galaxy rotation curve , weak gravitational lensing , dark matter , gravitational lens , astrophysics , modified newtonian dynamics , dark matter halo , galactic halo , galaxy , formalism (music) , strong gravitational lensing , gravitational potential , gravitational lensing formalism , equation of state , gravitation , halo , astronomy , quantum mechanics , art , musical , redshift , visual arts
We argue that combined observations of galaxy rotation curves and gravitational lensing not only allow the deduction of the mass profile of a galaxy, but also yield information about the pressure in the galactic fluid. We quantify this statement by enhancing the standard formalism for rotation curve and lensing measurements to a first post‐Newtonian approximation. This enhanced formalism is compatible with currently employed and established data analysis techniques, and can in principle be used to reinterpret existing data in a more general context. The resulting density and pressure profiles from this new approach can be used to constrain the equation of state of the galactic fluid, and therefore might shed new light on the persistent question of the nature of dark matter.