There are numerous types of extended radio sources that are produced by dual-jetted outflows associated with supermassive black hole systems, including FRI and FRII sources [
20,
21,
22]. The classification of large extended radio sources into two categories was proposed by Fanaroff and Riley in 1974 [
20], which are, thus, referred to as “FRI” and “FRII” sources. The radio emission is produced by a population of relativistic electrons in the presence of a magnetic field. FRI and FRII extended radio sources have a broad range of radio power and a broad range of morphological characteristics. The “supermassive black hole system” is taken to include the black hole; the material in the immediate vicinity of the black hole, which is referred to as the “accretion disk”; and the dual-jetted outflow. The dual-jetted outflow produces an extended radio source, that is, a radio source that is as large as or larger than the host galaxy.
FRII sources, also known as “classical doubles,” subdivide into numerous categories. Ref. [
23] identified five primary and three secondary types of FRII radio-source structure, for a total of eight FRII source types. For example, Refs. [
23,
24,
25] refer to the extended radio-emitting region that lies between the host supermassive black hole and each of the two ends of the extended radio source as the “radio bridge”, and this nomenclature is adopted here. Note that the “radio bridge” is sometimes referred to as “radio lobes”.
Of the five primary and three secondary types of FRII radio bridge structure [
23], only one exhibits a long, straight radio bridge with no distortions. This is the type 1 FRII source. These type 1 FRII sources exhibit a quite regular, cylindrical, cigar-shaped radio-bridge structure. Each of the remaining seven FRII categories exhibits various types of radio-bridge distortions. Following up on this, Ref. [
26] defined FRIIa sources as those with a radio-bridge distortion of any type and FRIIb sources as those with regular, cylindrical, cigar-shaped radio bridges—that is, type 1 FRII sources are referred to here as FRIIb sources, and the seven remaining FRII types defined by [
23] are referred to as FRIIa sources.
All of the radio sources discussed in this paper are FRIIb radio sources with a regular “cigar-shaped” radio bridge structure. It was found that the FRII type is strongly correlated with the radio power and that only the most powerful radio sources exhibited very regular “cigar-shaped” radio bridges, that is, are FRIIb sources [
25,
27]. The characteristics of FRIIb sources make them ideal for the studies presented here, and their properties are described in
Section 2.1. The radio-source properties indicate that the forward region of the source is moving into the ambient gas supersonically and producing a collisionless shock, indicating that the equations of strong shock physics can be applied to this region [
13], as discussed in
Section 2.2. The source characteristics indicate that FRIIb radio galaxies can be used to determine and study the cosmological model that describes our universe, as described in
Section 2.3. These studies allowed the total outflow lifetime to be empirically determined in a model-independent manner and independent of assumptions regarding minimum energy conditions, as described in
Section 2.2,
Section 2.3 and
Section 2.4. The relationship between the total outflow lifetime and black hole mass is discussed in
Section 2.5. The luminosity in directed kinetic energy can be combined with the outflow lifetime to determine the total energy transported from the supermassive black hole via the jetted outflow over the source lifetime, which is studied relative to black hole mass in
Section 2.6. The results presented in
Section 2.6 suggest a second method of studying the relationship between total outflow lifetime and black hole mass, which is presented in
Section 2.7. The results preseneted in
Section 2.6 also suggest a relationship between the luminosity in directed kinetic energy (also referred to as the ”beam power”) and the total black hole mass, as described in
Section 2.8. Finally, the total outflow lifetime is compared with the age of the universe at the redshift of each source to empirically determine the radio source selection function, which is presented in
Section 2.9.
2.1. FRIIb Radio Sources
The FRIIb sources discussed and studied here are type 1 FRII sources, as defined in [
23] and studied in detail in [
23,
24,
25,
28,
29,
30], for example. These are the most powerful FRII sources and have 178 MHz radio powers greater than about
, with radio powers obtained from radio flux densities using a standard LCDM cosmological model. Thus, FRIIb radio sources have radio powers that are greater than about
W/Hz at 178 MHz for a standard value of
. (Note that in work carried out a few decades ago, the standard cosmological model was an open, empty universe, and in that cosmological model, the 178 MHz power cut translates to about
.) They are selected from the 3CRR survey [
31].
FRIIb radio sources include only the most powerful FRII sources. For comparison, the LOFAR sample of 23,344 radio loud AGN includes fewer than about a hundred FRIIb sources, so only a small fraction—less than about 0.4%—of the those sources have 150 MHz radio powers typical of FRIIb sources, that is, have radio powers greater than about
W/Hz [
32]. This means that general conclusions reached with the LOFAR study do not apply to FRIIb sources. The radio sources and results discussed here are largely consistent with those obtained by [
33], including the conclusion that individual sources do not exhibit self-similar behavior. Ref. [
33] states the following: “We find that throughout the lifetime of an individual source its axial ratio steadily increases thus, for an individual source its expansion is not self-similar”.
In comparing the properties of the radio bridges of FRIIb sources with other studies, the results obtained by Daly et al. [
27] are quite instructive. In that work, each of 11 FRIIb radio galaxies was rotated into a horizontal position, and the properties of cross-sectional slices of the bridge were studied as a function of distance from the hotspot region, including the cross-sectional radio surface brightness profile, the width of the bridge, the radio emissivity as a function of the position across each slice, the first and second moments of the slice surface brightness, the mean surface brightness, the minimum-energy magnetic field strength, and the mean pressure of the relativistic plasma. These studies indicate that for FRIIb sources, the region in the immediate vicinity of the radio hotspots produces most of the total radio power of the source, and the radio bridge has a roughly constant radio surface brightness, emissivity, and bridge width. The results are consistent with the description of the sources as summarized in
Section 2.2 and
Section 2.3 and are consistent with the results of similar studies by Leahy et al. [
25].
The structure of the radio bridges of FRIIb radio galaxies indicate that the hotspot region, that is, each end of the “cigar-shaped” radio bridge, is moving into the ambient gas supersonically (e.g., [
24,
25,
27,
28,
29,
30,
34,
35]). Indeed, the shape of the radio bridge was used to infer the Mach number with which the radio bridge length increases, as well as the properties of the ambient gas [
34,
35], as discussed in
Section 2.2.
Refs. [
24,
25] conclude that the reason for radio bridge distortions exhibited by FRIIa sources (including four standard types and three complex types) is most likely the backflow of relativistic plasma in the radio bridge region. These authors conclude that backflow is not important for FRIIb sources and, thus, that the rate of growth of each source, referred to as the “lobe propagation velocity,” (
), as indicated by a radio spectral aging analysis, could be used to determine how rapidly the radio bridge length increases for FRIIb sources. Similar results have been obtained by other groups, such as Carilli et al. [
28], who studied the well-known FRIIb source Cygnus A.
The properties of the 31 radio galaxies discussed in
Section 2.3 are described by [
36]. The sample includes the 11 radio galaxies presented by Kharb et al. [
37], with details on individual source properties presented by O’Dea et al. [
30] and the 19 radio galaxies previously studied in [
38,
39,
40]. For some studies, source 3C427.1 was removed, as discussed by Daly et al. [
41]; these studies include 30 rather than 31 sources.
The determination of radio source parameters often depends upon the assumed underlying cosmological model. The effects of adopting different cosmological models is included in these studies, as discussed in
Section 2.3.
2.2. The Strong Shock Method
The radio bridge structure of FRIIb sources indicates that the hotspot region at the end of each side of the cigar-shaped radio bridge is moving into the ambient gas supersonically (e.g., [
23,
24,
25,
28,
29,
30,
33]), and is producing a collisionless shock, which is mediated by the magnetic field that permeates the plasma (e.g., [
13]). This means that the equations of strong shock physics can be applied to the region just behind the hotspot region (i.e., in the direction toward the supermassive black hole) (e.g., [
13,
28,
30,
34,
35,
42,
43]).
Applying the equations of strong shock physics allows empirical determinations of the rate at which energy is deposited into this region, referred to as the luminosity in directed kinetic energy (
L); the ambient gas density (
); the ambient gas pressure (
); and the ambient gas temperature (
). In these empirical determinations, a term that describes the offset from minimum energy conditions of the relativistic plasma in the radio bridge region is included (e.g., [
28,
30,
34,
35,
44,
45,
46]), as described below.
For the work discussed here, the key quantities are the luminosity in directed kinetic energy,
L (also referred to as the “beam power”), and
. The luminosity in directed kinetic energy and the ambient gas density are obtained by applying the equations that are valid for a strong shock:
and the ambient gas density is obtained with
, where
is the rate at which the source length is increasing, sometimes referred to as the “lobe propagation velocity”;
is the pressure of the relativistic plasma in the post-shock region (i.e., just behind the hotspot region); and
is the half-width of the radio bridge in the post-shock region (e.g., [
13,
27,
28,
30,
34,
35,
47]). Only radio galaxies were included in the study of O’Dea et al. [
30] so as to minimize projection effects.
Both
and
depend on offsets from minimum energy conditions in the post-shock region. Numerous observations and studies indicate that the relativistic plasma in the radio bridge region is offset from minimum energy conditions. The offset from minimum energy conditions is parameterized with
, where
B is the magnetic field strength and
is the minimum energy magnetic field strength obtained as described by O’Dea et al. [
30]. Typical values of
have been indicated by numerous empirical studies [
28,
30,
34,
35,
44,
45,
46]). Results obtained with both
and
are discussed and compared in [
30,
34,
35], for example.
A key result reported by O’Dea et al. [
30] is that the
b parameter cancels out in the empirical determination of
L [
13], that is, the way that
b enters
and
cancel out since
and
for
, as described in Section 4 of [
30]. The luminosity in directed kinetic energy (
L) shown in Figures 28 and 29 of [
30] as a function of core-hotspot separation for 31 FRIIb radio galaxies, assuming values of
and
, respectively, illustrate that the luminosity in directed kinetic energy obtained with the strong shock method is not affected by offsets from minimum energy conditions.
Thus, the empirically determined the luminosity in directed kinetic energy for the 31 FRIIb radio galaxies presented by [
30] are independent of offsets from minimum energy conditions in the radio bridge and, therefore, are quite reliable. Another key result illustrated by Figures 28 and 29 [
30] is that there is no indication of a relationship between (
L) and the current radio-source size; this is also indicated by the results shown in Tables 5 and 6 of that work. This indicates that each source has a roughly constant value of
L during its lifetime. A roughly constant value of
L per source during the source lifetime is also indicated by the structural properties of the cigar-shaped radio bridges of FRIIb sources (e.g., [
25,
27]).
A constant value of
of a given source over its lifetime is also indicated by the properties of FRIIb radio sources, since there is no correlation between the lobe propagation velocity (
) and the current radio-source size (see Tables 5 and 6 and Figures 22 and 23 of [
30]). This indicates that each source has a roughly constant value of
during its lifetime. The lobe propagation velocity is also independent of redshift [
30].
The
b parameter has an enormous impact on the ambient gas density, which scales as
(see Section 8.8.1 of [
34] and Section 7.4 of [
35]). This very strong dependence allowed for a constraint on the fractional dispersion of this parameter, and values of
for
, and
for
were obtained [
34]. A conservative bound on the source-to-source dispersion of the
b parameter of
was adopted by Wellman et al. [
34]. Thus, whatever the offsets from minimum energy conditions are within the radio bridge region, this offset must have a very small source-to-source dispersion for FRIIb radio sources.
The ambient gas density as a function of distance from the host supermassive black hole indicates an empirically determined composite density profile. The empirically determined composite profile is consistent with the host supermassive black hole residing near the center of a gaseous environment, similar to clusters of galaxies at low redshift, such as the cluster that hosts Cygnus A [
28,
34,
35,
44,
45]. Ref. [
34] concludes that FRIIb sources are located at the centers of cooling flow clusters of galaxies. This is consistent with results obtained by other groups for similar sources [
28,
44,
45].
The shape of the radio bridge was used to measure the Mach number with which the forward shock front (in the vicinity of the radio hotspots) propagates into the ambient medium, which can be combined with
to solve for the temperature of the ambient gas [
34]. Combining the temperature and density obtained for a sample of 12 radio galaxies and 6 radio loud quasars with redshift between 0 and 1.8, the authors of ref. [
34] found that the ambient gas density and temperature values were in good agreement with independently determined values and indicated that the sources lie near the center of a “cooling flow region,” likely at the center of a cluster or proto-cluster of galaxies. Similar results have been obtained by other groups [
28,
44,
45]. Thus, FRIIb radio sources are likely located at the center of cooling flow clusters or proto-clusters of galaxies.
Detailed studies of FRIIb sources indicate that the region in the immediate vicinity of the radio hotspots produces most of the total radio power of the source, and the radio bridge has a roughly constant radio surface brightness, emissivity, and radio bridge width [
25,
27]. The determination of each of these parameters depends upon the assumed underlying cosmological model. The effects of adopting different cosmological models was included in these studies.
2.3. Cosmological Studies
Several properties of FRIIb radio galaxies indicated that they could provide a useful tool to study and constrain cosmological models [
30,
36,
38,
40,
41,
47]. Detailed studies of FRIIb radio galaxies and radio loud quasars indicate that the radio bridge structures of radio galaxies are straight and regular, while those of radio loud quasars exhibit some distortions [
25]. In addition, studies of FRIIb radio galaxies suggest that these sources likely lie close to the plane of the sky and, thus, are not strongly affected by projection effects [
25,
48,
49,
50]. It was noted that the rate of growth of each source (
) for FRIIb radio galaxies is independent of source size and redshift, as discussed in
Section 2.2. Thus, the empirical data are consistent with a constant values of
L and
for a given FRIIb radio galaxy over its lifetime. For cosmological studies, the value of luminosity in directed kinetic energy for each side of each source was used [
30,
41].
Images of powerful classical double radio sources, referred to here as FRIIb sources, are presented in [
50]. Cygnus A, also known as 3C405, is an excellent example of an FRIIb source, and images of this source are presented in [
51].
The 30 individual FRIIb radio galaxies discussed here were drawn from the 3CRR survey of radio galaxies [
31], which is referred to as the “parent population,” (see [
36,
41] for a summary). It was noted that the source sizes of the parent population (as inferred from the angular separation between the radio core and radio hotspots on each side of each source) of the 70 galaxies in the parent population first increase with redshift, then decrease with redshift over the redshift interval from about zero to two for all reasonable cosmological models (as summarized by [
41]; see also [
38,
39,
40,
52]). The intrinsic physical source size, inferred from the core-hotspot separation, depends upon the assumed cosmological model, since the intrinsic size depends upon the angular size of the radio galaxy, the redshift of the galaxy, and the coordinate distance to that redshift (which is where the dependence on the cosmological model enters). The effect of an assumed cosmological model on the sizes of physical sources was present in all reasonable cosmological models, though the magnitudes of the changes were different for different models. Cosmological models including a cosmological constant, space curvature, dark energy, and a rolling scalar field have been studied [
36,
41].
As noted earlier, the velocity (
) with which an individual source is increasing in size was found to be independent of source size and independent of redshift [
30], where the size is measured from the location of the supermassive black hole to the hotspot on each side of each source. To reconcile the observed evolution of the mean source size of the parent population of radio galaxies with redshift with the lack of evolution of
, the ansatz that the total time the jetted outflow is produced by the supermassive black hole,
, could be written as a power law of the luminosity in directed kinetic energy, (
), was proposed, with
n related to the radio source parameter (
,
) [
47]. (Note that the is beam power,
L, is also referred to as luminosity in directed kinetic energy,
L, is also referred to as the “beam power.”) A characteristic source size (
) was defined and compared with the mean source size of the parent population as a function of redshift [
41].
This comparison depends rather strongly on the underlying cosmological model, as described in Section 2.1 of [
41]. Of course, obtaining the source size from the observed angular size depends linearly on the coordinate distance (
), while the characteristic source size [
]; see Equation (
3) and subsequent discussion presented in [
41]). Thus, requiring that values of
track the mean size of the parent population with redshift has a dependence of
. Requiring that the characteristic sizes of individual sources track that of the parent population as a function of redshift allows for determination of the best fit value of
n and determination of the underlying cosmological model [
36,
38,
41,
47,
52]. In each of these studies, the results consistently indicated that models which included a cosmological constant provided an excellent description of the data, and that a flat, matter-dominated universe was clearly ruled out.
The most recent constraint is obtained by fitting jointly to FRIIb radio galaxies and type Ia supernovae. The results indicate a value of
[
41], similar to and consistent with values obtained in earlier work. Thus, the ansatz expressed as
provides an excellent description of FRIIb sources, as discussed in more detail in
Section 2.4. Results obtained with FRIIb radio galaxies alone have consistently indicated a cosmological model that is in agreement with the currently accepted cosmological model for our universe [
36,
38,
40,
41,
47,
52].
2.4. The Total Lifetime of the Jetted Outflow
The method to obtain and study the total outflow lifetime for FRIIb sources is summarized in
Section 2.3; see Section 2.1 of [
41] for a more detailed description. The total jetted outflow lifetime (
) is the total time that the AGN will actively be producing collimated dual jets that terminate in the radio hotspots. For the studies of the relationship between total outflow lifetime and L discussed here, the total luminosity in directed kinetic energy is used and is taken to be the weighted sum of L from each side of each source [
53,
54].
The empirically determined values of the luminosity in directed kinetic energy (
L) and total jetted outflow lifetime (
) have no inputs related to the central black hole system, including no inputs related to the black hole or accretion disk (see
Section 2.2 and
Section 2.3). The key result for studies of the jetted outflow lifetime is that
(i.e.,
) and
where
is the total jetted outflow luminosity in directed kinetic energy, also referred to as the beam power, in units of
erg/s. For the 100 FRII sources studied by Daly [
55], the mean value and standard deviation of the luminosity in directed kinetic energy was found to be
. This range of values of
L is nearly identical to the range of values for the sources studied by O’Dea et al. [
30]. The uncertainty of
is dominated by the uncertainty of the luminosity in directed kinetic energy [
30,
53]. Given that the uncertainty of
is
(e.g., [
55]), the uncertainty of the total outflow lifetime is
. This indicates an uncertainty of
, since
. It is certainly possible that the constant of proportionality of 2.5 could have a systematic offset by up to a factor of about 1.5, as discussed by Daly et al. [
41].
The empirically determined values for the luminosity in directed kinetic energy obtained for individual sources are easily understood in the context of the jet production model of [
56] or [
57]. For example, Refs. [
54,
55,
58] showed that the empirically determined values of
L are consistent with predicted values for reasonable magnetic field strengths and black hole spin values, given the empirically determined values of black hole masses for these sources. Thus, even though the physical mechanism of jet production and the role of the magnetic field in launching the jets is quite different in these models, the equation relating
L to black hole mass, spin, and magnetic field strength are quite similar in both functional form and normalization, as discussed in detail by Daly [
55]. Accordingly, it is unlikely that the intrinsic values of
L are significantly different from the empirically determined values of
L.
The fact that the total jetted outflow lifetime of FRIIb sources is well represented as a function of only the luminosity in directed kinetic energy, which must be controlled by processes associated with the central black hole, is one indication that empirical studies of these sources can be used to understand the properties of the black hole at the center of the black hole system.
2.5. The Relationship Between the Total Lifetime of the Jetted Outflow and Black Hole Mass
The total lifetime of the jetted outflow given by Equation (
1) is obtained independent of the properties of the central region of the radio source. Thus, it is obtained independent of the black hole mass and accretion disk properties. The outflow lifetime can be compared with the mass of the host supermassive black hole to obtain the relationship between total outflow lifetime and black hole mass.
Of the original 31 radio galaxies studied by O’Dea et al. [
30], 19 had published supermassive black hole mass values, and these sources were studied by Daly [
54]. To increase the number of sources, the relationship between
L and the 178 MHz radio power (
P) for the sample of 31 sources mentioned above was obtained [
59]. The empirically determined relationship,
, was shown to be consistent with expectations based on the application of the strong shock method, given that the radio power is one of the factors that enters into the empirical determination of
L. Thus, it is unlikely that the empirically determined relationship between
L and
P results from a Malmquist bias due to a common dependence of these quantities on distance. To test for a Malmquist bias, the standard method of applying a partial correlation analysis was carried out using the method and code of [
60], which is described in detail by Timlin III et al. [
61]. The method is based on the application of Kendall’s partial
test, which numerically tests for a correlation between two parameters after removing the effect of a third parameter on their correlation. Following standard practice, redshift is used as a proxy for. The method was applied to the 31 sources studied by Daly et al. [
59], and the results indicate that the correlation between
L and
obtained by Daly et al. [
59] is significant at greater than about 97% confidence after removing any common dependence of these parameters on distance.
Applying the relationship between
L and
allowed the sample size to be significantly expanded, and the sample of 97 FRIIb radio sources with values of both
L and the black hole mass (
M), as presented and discussed by Daly [
62], are studied here. The black hole masses are obtained from [
63,
64], and the source types are from [
31]. Values of these quantities, plus values for three additional sources, are listed by Daly [
55]. Black hole masses and bolometric luminosities were available for 17 of the radio galaxies studied by O’Dea et al. [
30], and these sources are included in the samples studied in [
55,
62]. For the remaining sources, Equation (
1) is applied to convert
L to
.
Since the empirically determined values of
and
M are obtained independently, it is important to test for a Malmquist bias, that is, to test whether the relationship illustrated by
Figure 1 is intrinsic to the sources or is a result of a common dependence of
(or
L) and
M on distance. Applying the technique of Akritas & Siebert [
60] described above, the results indicate that the correlation between
and
M for the full sample of 97 sources is significant at greater than 99.98% confidence after removing any common dependence of these parameters on distance. The result for the sample of 55 HEG alone is significant at greater than 98.9% confidence after taking into account any common dependence on distance, and for the sample of 29 RLQ, this confidence is about 94.5%; the source types are defined in the caption of
Figure 1. Fo the sample of 13 LEG, the confidence is only 82%, which likely results from the small sample size. Thus, the correlations between the total outflow lifetime and black hole mass are reliable for the full sample of 97 sources and the sub-samples of 55 HEG and 29 RLQ.
Figure 1 illustrates the relationship between
and
M obtained for the sample of 97 sources studied; best fit parameters for the full sample and each subsample and are listed in the figure caption.
It should be noted that in the event that the outflow lifetime is set by a time scale related to a binary black hole system, the mass discussed here is that of the primary supermassive black hole, and the jetted outflow is taken to be anchored to the primary black hole, as discussed in
Section 3.2. The relationships obtained in the following sections are fully consistent with the outflow method of measuring the black hole spin and accretion disk properties of the primary supermassive black hole [
55].
2.6. Total Energy Deposited in Hotspot Region Relative to Black Hole Mass
The total energy removed from the central black hole system and deposited into the hotspot region over the lifetime of the source is
, where
L is the weighted sum of the beam power (i.e., luminosity in directed kinetic energy) from each side of the dual outflow. This total energy (
) was studied relative to the black hole mass (
M) for a sample of 19 FRIIb radio galaxies for which both
L, determined using the strong shock method (described in
Section 2.2) and
M were available [
54]. The distribution of values of
was found to have a very small dispersion. This was not the case for the sample of FRI “cavity” sources, which was found to have a very broad distribution of values, ranging from about
to about
[
54].
Of the 19 FRIIb radio galaxies included in the studies of [
54], 17 (all but 3C 55 and3C405, also known as Cygnus A) had sufficient information to be included in the studies of [
53]; all of these sources are HEG galaxies based on their nuclear spectroscopic properties. For these 17 sources, the mean value of
indicates the mean value of the total energy carried by the jetted outflow over the total outflow lifetime relative to the supermassive black hole mass of
Each of the 17 studied sources has a total luminosity in directed kinetic energy obtained with the strong shock method. Thus, they are independent of assumptions, including assumptions regarding offsets from minimum energy conditions, as reviewed in
Section 2.2, and, as such, are quite reliable.
To study
for larger samples of HEG FRIIb sources, the relationship between
L and the 178 MHz radio power was obtained as described in
Section 2.5 and applied, which led to a sample of 55 HEG FRIIb radio galaxies with values for both
L and
M [
62]. The total outflow energy (
) was obtained and studied relative to the black hole mass (
M) for this sample by Daly [
53], which indicated a value of
Similar values with a slightly larger uncertainty are obtained for other source types; see Table 3, column 9 of [
53]. The sample of 55 HEG radio galaxies includes the 17 sources for which
L and
are obtained as described above and in
Section 2.3 and
Section 2.4.
It is remarkable that even though the FRIIb sources discussed here have a broad range of values for each of the parameters (
,
,
, and redshift (z)), they have a very small range of values of
, as illustrated in Figure 19 of [
53]. In addition, the quantity
has no evolution with redshift, as indicated by the slope listed in column (9) of Table 3 for the full sample of the 100 studied sources and as illustrated in Figure 20 of [
53].
The study reported in [
53] included a comparison of values of
obtained for 100 supermassive black holes with different nuclear spectroscopic properties. In that work, high-excitation galaxies (HEG), low-excitation galaxies (LEG), quasars (Qs), and weak radio galaxies (W) were studied. There is no statistically significant difference in the mean values of
for sources with different nuclear spectroscopic properties (see column 9 of Table 3 in [
53]). Thus, there is no correlation between the nuclear spectroscopic properties of the gas in the immediate vicinity of the supermassive black hole and the total energy extracted from the supermassive black hole system relative to the black hole’s mass, though HEG sources exhibit a smaller dispersion relative to other source types, even after accounting for the larger number of sources in the HEG sample.
This is a second indication that a process directly related to the supermassive black hole is controlling the lifetime of the dual collimated outflow, with the first indication being Equation (
1).
The facts that
appears to be a constant and that
suggest that
or
—or both. This suggests that the relationship between the total lifetime of the jetted outflow and supermassive black hole mass could be obtained from
, as discussed in
Section 2.7. It also suggests that the relationship between luminosity in directed kinetic energy and black hole mass could be obtained from
, as discussed in
Section 2.8.
2.7. The Relationship Between Jetted Outflow Lifetime and Black Hole Mass Indicated by
A direct measurement of the relationship between the total outflow lifetime and black hole mass is discussed in
Section 2.6. It is suggested there that another indication of the relationship between the total lifetime of the jetted outflow and the black hole mass can be obtained by noting that
has a small dispersion.
The relationship between the lifetime for which the large-scale jetted outflow persists and the luminosity in directed kinetic energy indicated by Equation (
1) allows Equation (
2) or (
3) to be re-written as
. Substituting in the constants, Equation (
2) or (
3) indicates that
where
is the jetted outflow lifetime in units of
yrs and
is the black hole mass in units of
.
Given that
obtained for HEG radio galaxies has a quite narrow distribution, as indicated by Equation (
3), substituting in the value of
from this equation suggests that
where the coefficient has an uncertainty of about 40%. Values of
for the 55 HEG, 29 Q, and 13 LEG, plus 3 W sources, are listed in column 9 of Table 3 of [
53], and the mean values of
for these samples are all quite similar, though the dispersion for the HEG is significantly smaller than for the other samples or for the sample of all 100 sources studied in that work. The sources studied by Daly [
53] are the same sources illustrated in
Figure 1.