Milky Way mass models for orbit calculations | Astronomy & Astrophysics (A&A)

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Table 2

Properties of the best-fitting Model II.

Parameter	Value	Constraint	Value		Derived quantity	Value

			Observation	Model

r_⊙ (kpc)	8.35 ± 0.08	r_⊙ (kpc)	8.33 ± 0.35	8.35	v₀ (km s^-1)	240.4
M_b (M_gal)	175 ± 28	μ_SgrA^∗ (mas yr^-1)	−6.379 ± 0.026	−6.383	m_b (10⁹ M_⊙)	4.1 ± 0.7
M_d (M_gal)	2829 ± 192	Terminal velocities from H i	See Fig. 4	See Fig. 4	m_d (10¹⁰ M_⊙)	6.6 ± 0.5
M_h (M_gal)	^a	Terminal velocities from CO	See Fig. 4	See Fig. 4	m_h (10¹² M_⊙)
b_b (kpc)	0.184 ± 0.040	Circular velocities from masers	See Fig. 4	See Fig. 4	M_{R < 50 kpc} (10¹² M_⊙)	0.46 ± 0.03
a_d (kpc)		ρ_⊙ (M_⊙ pc^-3), Σ_1.1 (M_⊙ pc^-2)	0.102 ± 0.010, 74 ± 6	0.102, 75	M_{R < 100 kpc} (10¹² M_⊙)
b_d (kpc)	0.305 ± 0.020	σ_BW (km s^-1)	117 ± 15	116	M_{R < 200 kpc} (10¹² M_⊙)
a_h (kpc)	^a ^b	χ _∗	≤0	0.80	v_esc, ⊙ (km s^-1)	575.9
					A (km s^-1 kpc^-1)	15.11
					B (km s^-1 kpc^-1)	−13.68

Notes.The quoted uncertainties for the model parameters and masses are 90%-confidence limits (see notes on Table 1 for details).

^(a)

The large uncertainties are due to a strong correlation between M_h and a_h, see Fig. 5.

^(b)

Motivated by cosmological studies, the restriction a_h ≤ 200 kpc is imposed.

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