M94 as a Unique Testbed for Black Hole Mass Estimates and AGN Activity at Low Luminosities

Table 4

Ionizing and emission-line power.

	log𝐿H𝛼^a	log𝑄H𝛼^a	𝐿𝑖=𝐿H𝛼^b	𝑄𝑖=𝑄H𝛼^c
Palomar	>37.7	>49.3	<93	<2.75
Bok	37.5	49.0	165.9	4.9
MMTO	37.5	49.2	104.7	3.1
𝐻𝑆𝑇-STIS, narrow	36.8	48.4	759	22.4
𝐻𝑆𝑇-STIS, broad	37.9	49.5	57.5	1.6
PCA tomography	38.8	50.3	8.7	0.25

athe luminosities are measured in ergs⁻¹ and the photon rates in s⁻¹.
bthe minimum energy balance condition for AGN ionization is given by𝐿_𝑖/𝐿_H𝛼≳180 (when a fraction of 10% of ionizing photons photons is absorbed by the line-emitting gas).
cthe minimum photon balance condition for AGN ionization is given by 𝑄_𝑖/𝑄_H𝛼>2.2 for the narrow line regions, and 𝑄_𝑖/𝑄_H𝛼≳0.25 for the broad component.