J/ApJ/816/42 Mass models for the Milky Way (McGaugh, 2016)
The surface density profile of the Galactic disk from the terminal velocity
curve.
McGaugh S.S.
<Astrophys. J., 816, 42 (2016)>
=2016ApJ...816...42M 2016ApJ...816...42M (SIMBAD/NED BibCode)
ADC_Keywords: Models ; Milky Way
Keywords: Galaxy: fundamental parameters; Galaxy: kinematics and dynamics;
Galaxy: structure
Abstract:
The mass distribution of the Galactic disk is constructed from the
terminal velocity curve and the mass discrepancy-acceleration
relation. Mass models numerically quantifying the detailed surface
density profiles are tabulated. For R0=8kpc, the models have stellar
mass 5<M*<6x1010M☉, scale length 2.0≤Rd≤2.9kpc, LSR
circular velocity 222≤Θ0≤233km/s, and solar circle stellar
surface density 34≤Σd(R0)≤61M☉/pc2. The present
interarm location of the solar neighborhood may have a somewhat lower
stellar surface density than average for the solar circle. The Milky
Way appears to be a normal spiral galaxy that obeys scaling relations
like the Tully-Fisher relation, the size-mass relation, and the disk
maximality-surface brightness relation. The stellar disk is maximal,
and the spiral arms are massive. The bumps and wiggles in the terminal
velocity curve correspond to known spiral features (e.g., the
Centaurus arm is a ∼50% overdensity). The rotation curve switches
between positive and negative over scales of hundreds of parsecs. The
rms amplitude <|dV/dR|2>1/2, implying that commonly neglected
terms in the Jeans equations may be nonnegligible. The spherically
averaged local dark matter density is ρ0,DM∼0.009M☉/pc3
(0.34GeV/cm3). Adiabatic compression of the dark matter halo may help
reconcile the Milky Way with the c-V200 relation expected in
ΛCDM while also helping to mitigate the too-big-to-fail
problem, but it remains difficult to reconcile the inner
bulge/bar-dominated region with a cuspy halo. We note that NGC 3521 is
a near twin to the Milky Way, having a similar luminosity, scale
length, and rotation curve.
Description:
We have applied the mass discrepancy-acceleration relation (MDAR)
calibrated by external galaxies (McGaugh 2004ApJ...609..652M 2004ApJ...609..652M,
2014Galax...2..601M 2014Galax...2..601M) to the terminal velocity curves observed in the
first (Clemens 1985ApJ...295..422C 1985ApJ...295..422C) and fourth (Luna et al.
2006ApJ...641..938L 2006ApJ...641..938L; McClure-Griffiths & Dickey 2007ApJ...671..427M 2007ApJ...671..427M)
quadrants to construct mass models for the Milky Way.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 90 468 Detailed Milky Way mass models
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See also:
J/ApJS/210/3 : SDSS bulge, disk & total stellar mass estimates (Mendel+, 2014)
J/ApJ/716/198 : The DiskMass survey. I. (Bershady+, 2010)
J/AJ/136/2563 : HI Nearby Galaxy Survey, THINGS (Walter+, 2008)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Model Model name by quadrant and bulge fraction (1)
6- 14 F9.5 kpc Rad [0.1/150] Galaxy Model Radius
16- 25 F10.5 Msun/pc2 Ddisk [0/2029] Surface Density of the stellar disk
27- 36 F10.6 km/s Vdisk [-6.1/204.2] Circular speed of the disk
gravitational potential
38- 49 F12.6 Msun/pc2 Dbulge [0/51597] Surface Density of the bulge component
51- 60 F10.6 km/s Vbulge [0/231.2] Circular speed of the bulge
gravitational potential
62- 69 F8.5 Msun/pc2 Dgas [0/15] Surface Density of gas component
71- 80 F10.6 km/s Vgas [-22.6/60.3] Circular speed of the gas
gravitational potential
82- 90 F9.5 km/s Vtot [20.4/241.1] Total rotation curve of the model
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Note (1): Milky Way models are described in table 1 (see section 3):
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Mod B/T MB Md Rd Rp Vp Vb Vf thet0 A B V I K
10+9M☉ kpc km/s km/s/kpc M☉/L☉
-----------------------------------------------------------------------------
Q1ZB 0 0 51.5 2.0 6.1 237 204 204 222 13.8 -14.0 1.38 1.20 0.60
Q1MB 0.18 10 46.6 2.0 6.1 238 206 205 224 14.0 -14.0 1.52 1.32 0.65
Q1BB 0.30 16 37.6 2.0 6.3 241 208 208 224 13.9 -14.1 1.44 1.25 0.62
Q4ZB 0 0 55.1 2.4 6.4 239 205 207 232 15.5 -13.4 1.48 1.28 0.64
Q4MB 0.21 11.5 44.2 2.4 6.4 237 203 207 232 14.7 -14.3 1.49 1.30 0.64
Q4BB 0.34 20 38.2 2.9 6.4 236 201 208 233 13.9 -15.3 1.56 1.36 0.67
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The distance to the Galactic center is assumed to be R0=8.0kpc. The total
gas mass in all models is Mg=11.8x109M☉. This includes both atomic
and molecular gas and has been corrected to include helium and metals. The
mass-to-light ratios assume that the total luminosity of the Milky Way is
LV=37.3, LI=42.9, and LK=86.5x109L☉ (Drimmel & Spergel
2001ApJ...556..181D 2001ApJ...556..181D; Flynn et al. 2006MNRAS.372.1149F 2006MNRAS.372.1149F; Just et al.
2015MNRAS.451..149J 2015MNRAS.451..149J).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 16-Mar-2016