Table 2
Thermodynamic parameters (interstellar phase, temperature, mean hydrogen density and hydrogen mass) of the different structural components in our representation of the interstellar gas.
Component | Phase | T [K]a | nH [cm-3 b | MH [M⊙ c |
|
||||
Central cavity (CC) | ||||
Extended component | warm ionized | 7000 | 910 | 190 |
Minispiral | warm ionized | 7000 | 6200 | 12 |
Neutral streamers | atomic | 170 | 1.5 × 104 | 160 |
Central sphere | hot ionized | 1.5 × 107 | 18.5 | 0.12 |
|
||||
Circumnuclear ring (CNR) | ||||
Main molecular ring | molecular | 150 | 4.4 × 105 | 2 × 105 |
Photo-dissociated inner layer | atomic | 300 | 3.2 × 104 | 1300 |
|
||||
Sgr A East SNR | ||||
Extended component | hot ionized | 1.5 × 107 | 3.0 | 19 |
|
||||
Radio halo | ||||
Extended component | warm ionized | 7000 | 210 | 1.3 × 104 |
|
||||
Belt of molecular cloudsde | ||||
M−0.13−0.08 (SC) | molecular | 60 | 2 × 104 | 2.2 × 105 |
M−0.02−0.07 (EC) | molecular | 60 | 1.9 × 105 | |
Preshock core | 2 × 104 | 1.5 × 105 | ||
Swept-up shell | 3 × 104 | 3.8 × 104 | ||
Molecular ridge (MR) | molecular | 60 | 3 × 104 | (5.9−7.3) × 104 |
Swept-up shell | 3.8 × 104 | |||
Bridge | (2.1−3.5) × 104 | |||
Southern streamer (SS) | molecular | 60 | 3 × 104 | (1.6−3.2) × 104 |
Western streamer (WS) | molecular | 60 | 3 × 104 | 4.5 × 103 |
Northern ridge (NR) | molecular | 60 | 3 × 104 | 2.2 × 103 |
Notes.
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.
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