Renzo`s Rule: “For any feature in the luminosity profile there is a

Tuesday, February 28, 2012
Famaey & McGaugh (arxiv:1112.3960)
Renzo’s Rule: “For any feature in the luminosity profile there is a corresponding feature in the rotation
curve and vice versa.” (Sancisi 2004, IAU 220, 233)
McGaugh et al. (2007)
Enclosed dark matter mass
Spiral Galaxies
(Dark Matter Only)
Line fit to R > 1 kpc only
Tuesday, February 28, 2012
Strigari et al. (2008)
Line from preceding plot evaluated at 300 pc
Tuesday, February 28, 2012
Walker et al. (2010) ApJ, 717, L87
Enclosed dark matter mass
LSB galaxies
(Kuzio de Naray)
M31 dwarfs
mass @ r1/2
MW dwarfs
Tuesday, February 28, 2012
With Joe Wolf (UC Irvine)
(McGaugh & Wolf 2010, ApJ, 722, 248)
range of anisotropy
After lengthy, necessary, and gratuitously excessive
modeling of orbital anisotropy...
Estimate the circular velocity as Vc =
Tuesday, February 28, 2012
√
3σr1/2
(McGaugh & Wolf 2010, ApJ, 722, 248)
Baryonic TF relation
M31
dwarfs
Classical
dwarfs
Ultrafaint
dwarfs
deviations
Ursa Minor
Draco
akin to UF
Leo T unique among these satellite systems in having gas.
Tuesday, February 28, 2012
deviation from BTFR
deviations correlate with...
Luminosity
Effective radius
Surface brightness
Metallicity
Tuesday, February 28, 2012
Distance (or Δ-1)
Ellipticity
MV+6.4log(D)
Tidal susceptibility
Tuesday, February 28, 2012
Bellazzini et al. (2008)
deviation from BTFR
deviations correlate with...
Ellipticity
Distance
Tuesday, February 28, 2012
MOND
deviation from BTFR
dark matter
half light/tidal radius
half light/tidal radius
Stars safely within tidal radius.
Should be no tidal effects,
assuming equilibrium and
Pericenter ~ Distance (!)
Deviations set in about where
the size of the satellite becomes
comparable to the tidal radius.
Tuesday, February 28, 2012
ellipticity
deviation
γ=
!
D
r
"3/2 #
$
m 1/2
M
Tidal susceptibility depends on what you use for m.
IF L is your estimator, Fb & ε correlate with susceptibility
Tuesday, February 28, 2012
feedback
use metallicity to predict amount of baryonic mass loss
(assumes SF goes to completion; all gas expelled)
!
Mb
−[Fe/H]
fd =
1 + 0.4 × 10
fb Mvir
Tuesday, February 28, 2012
"
(Wyse, private communication)
reionization
Solid line: Crain et al. (2007)
Dashed lines: Gnedin (2011)
α = 1 (left); α = 2 (right)
Tuesday, February 28, 2012