Gas Disks and Supermassive Black Holes in Nearby Radio Galaxies

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for the gravitational potential from the stars and prospective nuclear black holes in each galaxy. In this chapter we present the techniques used to create model velocity profiles for each set of observations including the stars, and black holes with masses of 0, 1 × 10 8 M⊙ and 9 × 10 8 M⊙. We go on to discuss the models for each galaxy and compare the predicted kinematic signatures including the presence of supermassive black holes to the observed gas velocity profiles presented in Chapter 3. An important drawback of the approach of measuring black hole masses by using gas kinematics is that the gas dynamics may be affected by many non-gravitational sources and the gravitational motions may not be settled into a coplanar thin disk. We describe any such motions as ‘unsettled’. In §4.4.3 we will discuss some non- gravitational sources of kinetic energy in the gas and the consequences of unsettled motions for the determination of black hole masses. We do not produce model fits for each galaxy because, as we will see, a large proportion of the gas motion can not be described by simple circular-thin-disk rotation, rendering such fits difficult constrain and impossible to interpret meaningfully. 148
4.2 Thin disk models with and without a black hole We have created model velocity profiles assuming that the emission line gas that we observe originates from a thin rotating circular disk in each nucleus. This assumption matches our findings that the gas can be explained by a rotating system as we showed in Chapter 3; however, the large velocity dispersions that we measure indicate that the assumption that the disk is thin may not be very reliable. Yet for the purposes of modeling this assumption is necessary: to enable first steps to be made and to give us some handle on explanations of the nuclear gas dynamics. We use modeling techniques very similar to those described by van der Marel & van den Bosch (1998) and Verdoes Kleijn et al. (2002b) to generate velocity profiles along the observed slits for gas sitting in the gravitational potential generated by the stellar population of the galaxy and including (i) no black hole, (ii) a 1 × 10 8 M⊙ black hole and (iii) a 9×10 8 M⊙ black hole, and taking into account the instrumental PSF. These values of black hole mass are in the range typically conjectured for the nuclei of galaxies of this size, and we would not expect to resolve black holes of less than ∼ 1 ×10 8 M⊙ at the distances of the majority of the galaxies in our sample. We assume that the galaxy is at a distance D = v/H0, where v is the mean recessional 149
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Gas Disks and Supermassive Black Ho
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Abstract Gas Disks and Supermassive
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Contents 1 Introduction 1 1.1 Radio
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4.2.3 Stellar luminosity densities
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List of Tables 1.1 Properties of va
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5.1 Weighted mean kinematic paramet
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2.12 Optical continuum image of the
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4.14 Data-Model residuals with vary
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Acknowledgments First I would like,
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Chapter 1 Introduction The relation
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1.1 Radio galaxies A radio galaxy c
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This thesis focuses on a sample of
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et al., 2000; Tomita et al., 2000;
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larger than the generally expected
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most reliable is, of course, by the
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galaxies were obtained with the Fai
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• What connections can be found b
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Table 1.2. Reliable black hole mass
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Figure 1.2 An example of a FR-I (le
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Figure 1.4 From Martel et al. (2000
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Figure 1.6 The famous cartoon by Ph
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M BH (M Sun) 10 10 10 9 10 8 10 7 1
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dish flux density measurements at 1
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2.2.1 Radio properties Radio observ
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scribed by Verdoes Kleijn et al. (1
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Table 2.2. Multiwavelength Fluxes o
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0.5" Figure 2.1 Optical continuum i
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0.5" Figure 2.11 Optical continuum
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Chapter 3 STIS spectroscopy of the
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spectra in a future paper. We inclu
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3.2.1 Data Reduction We used the st
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λvac − λair λair = 6.4328 × 1
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line flux of the Hα line and colum
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3.3.3 Quantifying error sources The
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and velocity dispersions (dominated
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slits were aligned to a mean of the
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windows. The central kinematic and
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(slit one) than the central positio
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(see key in Figure 3.1 for an expla
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the gas exhibits a regular rotation
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show the relationship between the t
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3.5.2 Flux ratios and ionization In
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them to the samples of LINERS by Ho
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lines. 5. Flux-unconstrained Broad
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Table 3.1. HST-STIS G750M observing
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Table 3.3. Position angles of vario
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Table 3.5. NGC 193: Measured Parame
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Table 3.7. NGC 383: Measured Parame
Page 115 and 116: Table 3.9. NGC 741: Measured Parame
Page 117 and 118: Table 3.11. NGC 2329: Measured Para
Page 121 and 122: Table 3.15. UGC 7115: Measured Para
Page 133 and 134: Table 3.27. Presence of a Nuclear B
Page 135 and 136: Table 3.29. Fits to the central pix
Page 137 and 138: Table 3.31. Comparison of broad lin
Page 139 and 140: (a) (b) (i) (ii) (c) (i) (ii) (iii)
Page 141 and 142: Intensity (erg s −1 cm −2 Å
Page 161 and 162: Difference in mean velocity on each
Page 163 and 164: Mean velocity dispersion (km s -1 )
Page 165: Chapter 4 Modeling gas in gravitati
Page 169 and 170: gas disks were computed by making a
Page 171 and 172: intensity contours are aligned conc
Page 173 and 174: 4.2.4 Dynamical models As discussed
Page 175 and 176: are described in Appendix A of van
Page 177 and 178: models integrating using 150 by 150
Page 179 and 180: models. Pronounced differences can
Page 181 and 182: NGC 383: This S0 galaxy has a nucle
Page 183 and 184: at an offset of 80 km s −1 , equi
Page 185 and 186: gas velocities are very well settle
Page 187 and 188: NGC 5141: This S0 galaxy has a nucl
Page 189 and 190: e compatible with a ∼ 9 × 10 8 M
Page 191 and 192: hole masses for these galaxies. The
Page 193 and 194: numerical approaches they made the
Page 195 and 196: In the positive offset slit of NGC
Page 197 and 198: 4.5 Conclusions In this chapter we
Page 199 and 200: low statistical significance) possi
Page 201 and 202: Table 4.2. STIS PSF Parameters. Gau
Page 203 and 204: Table 4.4. Mass to light ratio (Υ)
Page 205 and 206: Table 4.6. Black hole signatures in
Page 207 and 208: weighted 600 500 400 300 200 100 =
Page 209 and 210: weighted 600 500 400 300 200 100 =
Page 211 and 212: weighted 500 400 300 200 100 = 0. k
Page 213 and 214: weighted 500 400 300 200 100 = 37.
Page 215 and 216: weighted 500 400 300 200 100 = 50.
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weighted 600 500 400 300 200 100 =
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weighted 500 400 300 200 100 = -50.
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weighted 800 600 400 200 = 280. km
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weighted 500 400 300 200 100 = -47.
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Gas Radial Velocity (km s -1 ) 400
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Gas Radial Velocity (km s -1 ) Gas
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Gas Radial Velocity (km s -1 ) 300
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v r (km s −1 ) 5000 4800 4600 440
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v r (km s −1 ) 4700 4600 4500 440
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M BH (M Sun) 10 10 10 9 10 8 10 7 1
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We showed that the mean dispersions
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within 100 pc of the nucleus: � N
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as face on disks are approached; th
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the inclination of the dust disk. O
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where we observe smaller and larger
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on scales of 1/8 the Effective radi
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may have some connections with the
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is well correlated with σc (correl
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e primarily driven by the central e
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organized rotation. This supports t
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Table 5.1. Weighted mean kinematic
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Table 5.3. Correlations between kin
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σ100 (km s -1 −−− ) 500 400
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−−− 2 2 σ100 / ∆100 100.00
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ε 100 (km s -1 ) 250 200 150 100 5
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∆ 100 (km s -1 ) 500 400 300 200
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ε 100 (km s -1 ) 250 200 150 100 5
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V-Band I-Band VLA Peak VLBA Peak 10
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42 41 40 39 38 M87 nuclear SED 37 8
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ased on the gas kinematics? • How
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emaining galaxies may be of particu
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in nearby galaxies, and is being us
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of the features observed in the vel
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From the work presented in this dis
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Comparing samples of active and qui
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Bower, G. A., Green, R. F., Danks,
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Herrnstein, J. R., Moran, J. M., Gr
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Quataert, E., & Narayan, R. 2001, A
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Gas Disks and Supermassive Black Holes in Nearby Radio Galaxies

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