A_{c}(r) | Cloud cross section |
A_{ji} | Radiative transition rate |
a | Damping constant |
B_{ij} | Aborption coefficient |
b_{i} | Derture coefficient for level i |
C_{ij} | Collisional excitation rate |
C(r) | Cumulative covering factor (up to distance r) |
c | Velocity of light |
c_{s} | Sound speed |
E_{l}(r) | Cumulative line flux (up to distance r) |
E_{} | Line profile |
E(t) | Emission line light curve |
E_{ij} | Energy separation of levels ij |
EW | Equivalent width |
F_{} | Monochromatic continuum flux |
f_{d} | Drag force |
f_{ij} | Oscillator strength |
G | Gravitational constant |
g_{ff} | Gaunt factor for free-free transition |
g_{G} | Gravitational acceleration |
g_{i} | Statistical weight of level i |
g_{rad} | Radiative acceleration |
h | Planck's constant |
I_{} | Radiation intensity |
J | Mean radiation intensity |
j_{c}(r) | Total cloud emission |
k | Boltzmann constant |
k() | Number of scattering factor |
k'() | Path length increase factor |
L | Integrated continuum luminosity |
L_{46} | Luminosity in 10^{46} erg s^{-1} |
L_{} | Monochromatic continuum luminosity |
L(t) | Continuum light curve |
L_{Edd} | Eddington luminosity |
M_{c} | Mass of a cloud |
M_{BH} | Mass of the central black hole |
M_{9} | M_{BH} / 10^{9} M_{} |
Accretion rate | |
Accretion rate in units of L/L_{Edd} | |
m_{e} | Electron mass |
m_{p} | Proton mass |
m_{} | Magnitude of extinction |
N | Particle number density |
N_{10} | N / 10^{10} cm^{-3} |
N_{e} | Electron density |
N_{HIM} | Density of the hot inter-cloud medium |
N_{col} | Column density |
n_{c}(r) | Number of clouds per unit volume at distance r |
n_{i} | Population of level i |
P | Pressure |
Q() | Number of scattering before escape |
R_{c} | Radius of a cloud |
r | Distance of a cloud |
r_{av} | Emissivity-weighted average radius |
r_{in} | Inner radius of the emission line region |
r_{out} | Outer radius of the emission line region |
S | Source function |
T_{C} | Compton temperature |
T_{e} | Electron temperature |
T_{ex} | Excitation temperature |
T_{HIM} | Temperature of the hot inter-cloud medium |
T_{rad} | Radiation temperature |
t_{dyn} | Dynamical time |
t_{rec} | Recombination time |
t_{sc} | Sound-crossing time |
U | Ionization parameter |
V_{c} | Volume of a cloud |
v(r) | Cloud velocity at a distance r |
v_{Doppler} | Doppler velocity |
v_{3000} | v/3000 km s^{-1} |
X_{c} | Relative continuum opacity |
X_{l} | Relative line opacity |
Z | Nuclear charge |
z | Redshift |
Recombination coefficient | |
_{T} | Temperature averaged recombination coefficient |
Escape probability | |
_{eff} | Effective escape probability |
Continuum spectral index | |
_{l}(r) | Line emission (erg s^{-1} cm^{-2}) |
_{} | Line emission coefficient |
_{} | Continuum occupation number |
_{} | Line absorption coefficient |
_{c} | Continuum absorption cross section at line center |
_{l} | Line absorption cross section at line center |
_{ij } | Wavelength of the ij transition |
_{0} | Line center wavelength |
µ | cos in a spherical coordinate system |
Frequency | |
_{0} | Threshold ionization frequency |
Mean photon frequency or mean photon energy | |
_{cut} | Cut-off frequency |
(radiation pressure) / (gas pressure) U/T | |
_{} | Continuum absorption cross section |
_{c} | Effective Compton cooling cross section |
_{es} | Electron scattering cross section |
_{h} | Effective Compton heating cross section |
Optical depth | |
_{in} | Optical depth to the inner (illuminated) face of the cloud |
_{out} | Optical depth to the outer face of the cloud |
_{} | Normalized line profile |
(t) | Transfer function |
_{ij} | Effective collision strength |
1 / t |