The actual temperature ranges, accounting for observational uncertainties, model approximations and true physical dispersion, are [in K]: central cavity:  ≈ (5000−13 000) for the warm ionized gas;  ≈(100−240) for the atomic gas;  ≈ (1.4−2.3) × 10⁷ for the hot ionized gas. CNR:  ≈ (40−300) for the molecular gas;  ≈(200−1000) for the atomic gas. Sgr A East:  ≈(1−7) × 10⁷. Radio halo:  ≈ (5000−10 000). Belt of molecular clouds:  ≈ (15−200).

The actual hydrogen density ranges, accounting for observational uncertainties, model approximations and true physical dispersion, are [in cm^-3]: central cavity:  ≈ (10³ − 2 × 10⁵) for the warm ionized gas;  ≈ (2 × 10³−3 × 10⁵) for the atomic gas;  ≈ (10−40) for the hot ionized gas. CNR:  ≈ (10⁴−2 × 10⁸) for the molecular gas;  ≈ (10⁴−2 × 10⁵) for the atomic gas. Sgr A East:  ≈ (1.5−30). Radio halo:  ≈ (10−1000). Belt of molecular clouds:  ≈ (10⁴−4 × 10⁶).

The errors in our adopted masses are estimated as follows: a factor  ~4 for the ionized components (including uncertainties in the observed emission measures, in the projected surface areas and in the line-of-sight depths); a factor  ~5 for the atomic and molecular components (including uncertainties in the measured column densities, in the tracer-to-hydrogen ratios and in the projected surface areas). For the radio halo, the error is in fact larger than a factor  ~4, as the relative contribution from warm ionized gas to the observed radio emission is itself very uncertain.

The swept-up shell is indicated twice, because it is part of both M − 0.02 − 0.07 and the molecular ridge.

The mass ranges given for the Bridge (and hence the molecular ridge) and the southern streamer correspond to the range in the line-of-sight coordinate of the center of M − 0.13-0.08, x_SC = (4−12) pc.