We present new upper limits for black hole masses in extremely late type spiral galaxies. We confirm that this class of galaxies has black holes with masses less than 106 , if any. We also derive new upper limits for nuclear star cluster masses in massive galaxies with previously determined black hole masses. We use the newly derived upper limits and a literature compilation to study the low mass end of the global-to-nucleus relations. We find the following. (1) The - relation cannot flatten at low masses, but may steepen. (2) The - relation may well flatten in contrast. (3) The -Sersic relation is able to account for the large scatter in black hole masses in low-mass disk galaxies. Outliers in the -Sersic relation seem to be dwarf elliptical galaxies. When plotting versus we find three different regimes: (a) nuclear cluster dominated nuclei, (b) a transition region, and (c) black hole-dominated nuclei. This is consistent with the picture, in which black holes form inside nuclear clusters with a very low-mass fraction. They subsequently grow much faster than the nuclear cluster, destroying it when the ratio / grows above 100. Nuclear star clusters may thus be the precursors of massive black holes in galaxy nuclei. 1. Introduction Supermassive black holes (BHs) are thought to be ubiquitous in the nuclei of massive galaxies. The discovery of a number of tight correlations between the global properties of galaxies and the properties of their nuclei (e.g., [1–3]) has led astronomers to realize that the evolution of galaxies may be closely linked to their nuclear properties. However, the nuclei of galaxies do not only host massive BHs but also host massive star clusters, commonly called nuclear star clusters (NCs). (Note that we here make the distinction between nucleus, that is, the location at the very center, and nuclear star cluster. Often the NC has been called nucleus or stellar nucleus in the past, but this seems ambiguous to us). The overall nucleation frequency is around 75% over all Hubble types ([4–6], hereafter B02), but NCs seem to be absent in the most massive galaxies [5, 7]. NCs typically have stellar velocity dispersions of 15– , effective radii of a few parsecs, and dynamical masses of ~106–107 (B02 [8, 9]). Moreover, they show stellar populations of multiple ages [10–12], pointing towards them having a complex formation history. This might be related to their special location in the galaxy, as on average, NCs appear to sit at the photometric centre of their host galaxy [6, 13]. We recently showed that for bulgeless galaxies their location
References
[1]
L. Ferrarese and D. Merritt, “A fundamental relation between supermassive black holes and their host galaxies,” Astrophysical Journal Letters, vol. 539, no. 1, pp. L9–L12, 2000.
[2]
K. Gebhardt, R. Bender, G. Bower et al., “A relationship between nuclear black hole mass and galaxy velocity dispersion,” Astrophysical Journal Letters, vol. 539, no. 1, pp. L13–L16, 2000.
[3]
N. H？ring and H.-W. Rix, “On the black hole mass-bulge mass relation,” Astrophysical Journal Letters, vol. 604, no. 2, pp. L89–L92, 2004.
[4]
C. M. Carollo, M. Stiavelli, and J. Mack, “Spiral galaxies with WFPC2. II. The nuclear properties of 40 objects,” Astronomical Journal, vol. 116, no. 1, pp. 68–84, 1998.
[5]
P. C？té, S. Piatek, L. Ferrarese et al., “The ACS virgo cluster survey. VIII. The nuclei of early-type galaxies,” Astrophysical Journal, vol. 165, no. 1, pp. 57–94, 2006.
[6]
T. B？ker, S. Laine, R. P. Van Der Marel et al., “A Hubble Space Telescope census of nuclear star clusters in late-type spiral galaxies. I. Observations and image analysis,” Astronomical Journal, vol. 123, no. 3, pp. 1389–1410, 2002.
[7]
A. W. Graham, C. A. Onken, E. Athanassoula, and F. Combes, “An expanded Mbh-σ diagram, and a new calibration of active galactic nuclei masses,” Monthly Notices of the Royal Astronomical Society, vol. 412, no. 4, pp. 2211–2228, 2011.
[8]
T. B？ker, M. Sarzi, D. E. Mclaughlin et al., “A Hubble Space Telescope census of nuclear star clusters in late-type spiral galaxies. II. Cluster sizes and structural parameter correlations,” Astronomical Journal, vol. 127, no. 1, pp. 105–118, 2004.
[9]
C. J. Walcher, R. P. Van Der Marel, D. Mclaughlin et al., “Masses of star clusters in the nuclei of bulgeless spiral galaxies,” Astrophysical Journal, vol. 618, no. 1, pp. 237–246, 2005.
[10]
J. Rossa, R. P. Van Der Marel, T. B？ker et al., “Hubble Space Telescope stis spectra of nuclear star clusters in spiral galaxies: dependence of age and mass on hubble type,” Astronomical Journal, vol. 132, no. 3, pp. 1074–1099, 2006.
[11]
A. C. Seth, J. J. Dalcanton, P. W. Hodge, and V. P. Debattista, “Clues to nuclear star cluster formation from edge-on spirals,” Astronomical Journal, vol. 132, no. 6, pp. 2539–2555, 2006.
[12]
C. J. Walcher, T. B？ker, S. Charlot et al., “Stellar populations in the nuclei of late-type spiral galaxies,” Astrophysical Journal, vol. 649, no. 2, pp. 692–708, 2006.
[13]
B. Binggeli, F. Barazza, and H. Jerjen, “Off-center nuclei in dwarf elliptical galaxies,” Astronomy and Astrophysics, vol. 359, no. 2, pp. 447–456, 2000.
[14]
N. Neumayer, C. J. Walcher, D. Andersen, S. F. Sánchez, T. B？ker, and H. -W. Rix, “Two-dimensional Hα kinematics of bulgeless disc galaxies,” Monthly Notices of the Royal Astronomical Society, vol. 413, no. 3, pp. 1875–1888, 2011.
[15]
L. Ferrarese, P. C？té, E. Dalla Bontà et al., “A fundamental relation between compact stellar nuclei, supermassive black holes, and their host galaxies,” Astrophysical Journal Letters, vol. 644, no. 1, pp. L21–L24, 2006.
[16]
E. H. Wehner and W. E. Harris, “Supermassive black holes to dwarf elliptical nuclei: a mass continuum,” Astrophysical Journal Letters, vol. 644, no. 1, pp. L17–L20, 2006.
[17]
B. G. Elmegreen, F. Bournaud, and D. M. Elmegreen, “Nuclear black hole formation in clumpy galaxies at high redshift,” Astrophysical Journal Letters, vol. 684, no. 2, pp. 829–834, 2008.
[18]
J. A. Regan and M. G. Haehnelt, “Pathways to massive black holes and compact star clusters in pre-galactic dark matter haloes with virial temperatures 10 000？K,” Monthly Notices of the Royal Astronomical Society, vol. 396, no. 1, pp. 343–353, 2009.
[19]
L. Mayer, S. Kazantzidis, A. Escala, and S. Callegari, “Direct formation of supermassive black holes via multi-scale gas inflows in galaxy mergers,” Nature, vol. 466, no. 7310, pp. 1082–1083, 2010.
[20]
V. Bromm and N. Yoshida, “The first galaxies,” Annual Review of Astronomy and Astrophysics, vol. 49, no. 1, pp. 373–407, 2011.
[21]
M. Hartmann, V. P. Debattista, A. Seth, M. Cappellari, and T. R. Quinn, “Constraining the role of star cluster mergers in nuclear cluster formation: simulations confront integral-field data,” Monthly Notices of the Royal Astronomical Society, vol. 418, no. 4, pp. 2697–2714, 2011.
[22]
T. Ebisuzaki, J. Makino, and T. G. Tsuru, “Missing link found? The "runaway" path to supermassive black holes,” Astrophysical Journal Letters, vol. 562, no. 1, pp. L19–L22, 2001.
[23]
S. F. Portegies Zwart, H. Baumgardt, P. Hut, J. Makino, and S. L.W. McMillan, “Formation of massive black holes through runaway collisions in dense young star clusters,” Nature, vol. 428, no. 6984, pp. 724–726, 2004.
[24]
M. A. Gürkan, M. Freitag, and F. A. Rasio, “Formation of massive black holes in dense star clusters. I. Mass segregation and core collapse,” Astrophysical Journal Letters, vol. 604, no. 2, pp. 632–652, 2004.
[25]
M. Freitag, F. A. Rasio, and H. Baumgardt, “Runaway collisions in young star clusters—I. Methods and tests,” Monthly Notices of the Royal Astronomical Society, vol. 368, no. 1, pp. 121–140, 2006.
[26]
E. Gaburov, A. Gualandris, and S. Portegies Zwart, “On the onset of runaway stellar collisions in dense star clusters—I. Dynamics of the first collision,” Monthly Notices of the Royal Astronomical Society, vol. 384, no. 1, pp. 376–385, 2008.
[27]
E. Glebbeek, E. Gaburov, S. E. De Mink, O. R. Pols, and S. F.P. Zwart, “The evolution of runaway stellar collision products,” Astronomy and Astrophysics, vol. 497, no. 1, pp. 255–264, 2009.
[28]
A. V. Filippenko and L. C. Ho, “A low-mass central black hole in the bulgeless Seyfert 1 galaxy NGC 4395,” Astrophysical Journal Letters, vol. 588, no. 1, pp. L13–L16, 2003.
[29]
A. Seth, M. Agüeros, D. Lee, and A. Basu-Zych, “The coincidence of nuclear star clusters and active galactic nuclei,” Astrophysical Journal Letters, vol. 678, no. 1, pp. 116–130, 2008.
[30]
R. Sch？del, A. Eckart, T. Alexander et al., “The structure of the nuclear stellar cluster of the Milky Way,” Astronomy and Astrophysics, vol. 469, no. 1, pp. 125–146, 2007.
[31]
R. Genzel, F. Eisenhauer, and S. Gillessen, “The Galactic center massive black hole and nuclear star cluster,” Reviews of Modern Physics, vol. 82, no. 4, pp. 3121–3195, 2010.
[32]
M. Freitag, M. Atakan Gürkan, and F. A. Rasio, “Runaway collisions in young star clusters—II. Numerical results,” Monthly Notices of the Royal Astronomical Society, vol. 368, no. 1, pp. 141–161, 2006.
[33]
A. W. Graham and S. P. Driver, “A log-quadratic relation for predicting supermassive black hole masses from the host bulge sérsic index,” Astrophysical Journal Letters, vol. 655, no. 1, pp. 77–87, 2007.
[34]
J. E. Greene, C. Y. Peng, M. Kim et al., “Precise black hole masses from megamaser disks: black hole-bulge relations at low mass,” Astrophysical Journal Letters, vol. 721, no. 1, pp. 26–45, 2010.
[35]
A. V. Filippenko and W. L. W. Sargent, “Discovery of an extremely low luminosity Seyfert 1 nucleus in the dwarf galaxy NGC 4395,” Astrophysical Journal, vol. 342, pp. L11–L14, 1989.
[36]
J. C. Shields, C. J. Walcher, T. B？ker, L. C. Ho, H. -W. Rix, and R. P. Van Der Marel, “An accreting black hole in the nuclear star cluster of the bulgeless galaxy NGC 1042,” Astrophysical Journal Letters, vol. 682, no. 1, pp. 104–109, 2008.
[37]
A. J. Barth, L. E. Strigari, M. C. Bentz, J. E. Greene, and L. C. Ho, “Dynamical constraints on the masses of the nuclear star cluster and black hole in the late-type spiral galaxy NGC 3621,” Astrophysical Journal Letters, vol. 690, no. 1, pp. 1031–1044, 2009.
[38]
M. Gliozzi, S. Satyapal, M. Eracleous, L. Titarchuk, and C. C. Cheung, “A chandra view of NGC 3621: a bulgeless galaxy hosting an agn in its early phase?” Astrophysical Journal Letters, vol. 700, no. 2, pp. 1759–1767, 2009.
[39]
S. Satyapal, D. Vega, R. P. Dudik, N. P. Abel, and T. Heckman, “Spitzer uncovers active galactic nuclei missed by optical surveys in seven late-type galaxies,” Astrophysical Journal Letters, vol. 677, no. 2, pp. 926–942, 2008.
[40]
J. E. Greene and L. C. Ho, “A new sample of low-mass black holes in active galaxies,” Astrophysical Journal Letters, vol. 670, no. 1, pp. 92–104, 2007.
[41]
A. J. Barth, J. E. Greene, and L. C. Ho, “Low-mass seyfert 2 galaxies in the sloan digital sky survey,” Astronomical Journal, vol. 136, no. 3, pp. 1179–1200, 2008.
[42]
W. McAlpine, S. Satyapal, M. Gliozzi, C. C. Cheung, R. M. Sambruna, and M. Eracleous, “Black holes in bulgeless galaxies: an XMM-Newton investigation of NGC 3367 and NGC 4536,” Astrophysical Journal Letters, vol. 728, article 25, 2011.
[43]
K. Gebhardt, T. R. Lauer, J. Kormendy et al., “M33: a galaxy with no supermassive black hole,” Astronomical Journal, vol. 122, no. 5, pp. 2469–2476, 2001.
[44]
D. Merritt, L. Ferrarese, and C. L. Joseph, “No supermassive black hole in M33?” Science, vol. 293, no. 5532, pp. 1116–1118, 2001.
[45]
P. Erwin and D. Gadotti, “Do nuclear star clusters and supermassive black holes follow the same host-galaxy correlations?” in Proceedings of the American Institute of Physics Conference, V. P. Debattista and C. C. Popescu, Eds., vol. 1240, pp. 223–226, 2010.
[46]
J. Kormendy, R. Bender, and M. E. Cornell, “Supermassive black holes do not correlate with galaxy disks or pseudobulges,” Nature, vol. 469, no. 7330, pp. 374–376, 2011.
[47]
M. Volonteri, G. Lodato, and P. Natarajan, “The evolution of massive black hole seeds,” Monthly Notices of the Royal Astronomical Society, vol. 383, no. 3, pp. 1079–1088, 2008.
[48]
T. Di Matteo, V. Springel, and L. Hernquist, “Energy input from quasars regulates the growth and activity of black holes and their host galaxies,” Nature, vol. 433, no. 7026, pp. 604–607, 2005.
[49]
P. F. Hopkins, L. Hernquist, T. J. Cox, T. Di Matteo, B. Robertson, and V. Springel, “A unified, merger-driven model of the origin of starbursts, quasars, the cosmic X-ray background, supermassive black holes, and galaxy spheroids,” Astrophysical Journal, vol. 163, no. 1, pp. 1–49, 2006.
[50]
C. Y. Peng, “How mergers may affect the mass scaling relation between geuvitationally bound systems,” Astrophysical Journal Letters, vol. 671, no. 2, pp. 1098–1107, 2007.
[51]
E. Noyola, K. Gebhardt, M. Kissler-Patig et al., “Very large telescope kinematics for omega Centauri: further support for a central black hole,” Astrophysical Journal Letters, vol. 719, no. 1, pp. L60–L64, 2010.
[52]
K. Jahnke and A. Macciò, “The Non-causal Origin of the Black-hole-galaxy Scaling Relations,” The Astrophysical Journal, vol. 734, no. 2, article 92, 2011.
[53]
E. Emsellem, G. Monnet, and R. Bacon, “The multi-gaussian expansion method: a tool for building realistic photometric and kinematical models of stellar systems I. The formalism,” Astronomy and Astrophysics, vol. 285, pp. 723–738, 1994.
[54]
M. Cappellari, “Efficient multi-Gaussian expansion of galaxies,” Monthly Notices of the Royal Astronomical Society, vol. 333, no. 2, pp. 400–410, 2002.
[55]
J. Krist, Astronomical Data Analysis Software and Systems IV, vol. 77 of Astronomical Society of the Pacific Conference Series, 1995, edited by R. A. Shaw, H. E. Payne and J. J. E. Hayes.
[56]
M. Cappellari, “Measuring the inclination and mass-to-light ratio of axisymmetric galaxies via anisotropic Jeans models of stellar kinematics,” Monthly Notices of the Royal Astronomical Society, vol. 390, no. 1, pp. 71–86, 2008.
[57]
P. Serra and S. C. Trager, “On the interpretation of the age and chemical composition of composite stellar populations determined with line-strength indices,” Monthly Notices of the Royal Astronomical Society, vol. 374, no. 3, pp. 769–774, 2007.
[58]
K. Gültekin, D. O. Richstone, K. Gebhardt et al., “The M-σ and M-L relations in galactic bulges, and determinations of their intrinsic scatter,” Astrophysical Journal Letters, vol. 698, no. 1, pp. 198–221, 2009.
[59]
B. M. Peterson, M. C. Bentz, L. -B. Desroches et al., “Multiwavelength monitoring of the dwarf seyfert 1 galaxy NGC 4395. I. A reverberation-based measurement of the black hole mass,” Astrophysical Journal, vol. 632, no. 2, pp. 799–808, 2005.
[60]
A. J. Barth, L. C. Ho, R. E. Rutledge, and W. L.W. Sargent, “POX 52: a dwarf Seyfert 1 galaxy with an intermediate-mass black hole,” Astrophysical Journal Letters, vol. 607, no. 1, pp. 90–102, 2004.
[61]
M. Valluri, L. Ferrarese, D. Merritt, and C. L. Joseph, “The low end of the supermassive black hole mass function: constraining the mass of a nuclear black hole in NGC 205 via stellar kinematics,” Astrophysical Journal, vol. 628, no. 1, pp. 137–152, 2005.
[62]
T. B？ker, R. P. Van Der Marel, and W. D. Vacca, “CO band head spectroscopy of IC 342: mass and age of the nuclear star cluster 1,” Astronomical Journal, vol. 118, no. 2, pp. 831–842, 1999.
[63]
A. C. Seth, M. Cappellari, N. Neumayer et al., “The NGC 404 nucleus: star cluster and possible intermediate-mass black hole,” Astrophysical Journal Letters, vol. 714, no. 1, pp. 713–731, 2010.
[64]
K. Gebhardt, R. M. Rich, and C. H.O. Luis, “An intermediate-mass black hole in the globular cluster G1: improved significance from New Keck and Hubble Space Telescope observations,” Astrophysical Journal, vol. 634, no. 2, pp. 1093–1102, 2005.
[65]
E. Noyola, K. Gebhardt, and M. Bergmann, “Gemini and Hubble Space Telescope evidence for an intermediate-mass black hole in ω Centauri,” Astrophysical Journal Letters, vol. 676, no. 2, pp. 1008–1015, 2008.
[66]
B. Jalali, H. Baumgardt, M. Kissler-Patig et al., “A Dynamical N-body Model for the Central Region of Centauri,” http://adsabs.harvard.edu/abs/2011arXiv1111.5011J.
[67]
N. Lützgendorf, M. Kissler-Patig, E. Noyola et al., “Kinematic signature of an intermediate-mass black hole in the globular cluster NGC 6388,” Astronomy & Astrophysics, vol. 533, artilce A36, 2011.
[68]
J. Anderson and R. P. Van Der Marel, “New limits on an intermediate-mass black hole in omega centauri. I. Hubble Space Telescope photometry and proper motions,” Astrophysical Journal Letters, vol. 710, no. 2, pp. 1032–1062, 2010.
[69]
R. P. Van Der Marel and J. Anderson, “New limits on an intermediate-mass black hole in omega centauri. II. Dynamical models,” Astrophysical Journal Letters, vol. 710, no. 2, pp. 1063–1088, 2010.
[70]
H. Baumgardt, J. Makino, H. U. T. Piet, S. McMillan, and S. P. Zwart, “A dynamical model for the globular cluster G1,” Astrophysical Journal Letters, vol. 589, no. 1, pp. L25–L28, 2003.
[71]
J. E. Greene, L. C. Ho, and A. J. Barth, “Black holes in pseudobulges and spheroidals: a change in the black hole-bulge scaling relations at low mass,” Astrophysical Journal Letters, vol. 688, no. 1, pp. 159–179, 2008.
[72]
K. Ganda, R. F. Peletier, M. Balcells, and J. Falcón-Barroso, “The nature of late-type spiral galaxies: structural parameters, optical and near-infrared colour profiles and dust extinction,” Monthly Notices of the Royal Astronomical Society, vol. 395, no. 3, pp. 1669–1694, 2009.
[73]
T. Weinzirl, S. Jogee, S. Khochfar, A. Burkert, and J. Kormendy, “Bulge n and B/T in high-mass galaxies: constraints on the origin of bulges in hierarchical models,” Astrophysical Journal Letters, vol. 696, no. 1, pp. 411–447, 2009.
[74]
C. Y. Peng, L. C. Ho, C. D. Impey, and H.-W. Rix, “Detailed structural decomposition of galaxy images,” Astronomical Journal, vol. 124, no. 1, pp. 266–293, 2002.
[75]
A. W. Graham and L. R. Spitler, “Quantifying the coexistence of massive black holes and dense nuclear star clusters,” Monthly Notices of the Royal Astronomical Society, vol. 397, no. 4, pp. 2148–2162, 2009.
[76]
K. Gültekin, S. Tremaine, A. Loeb, and D. O. Richstone, “Observational Selection Effects and the M-σ Relation,” The Astrophysical Journal, vol. 738, no. 1, article 17, 2011.
[77]
C. Scorza and F. C. Van Den Bosch, “Nuclear stellar discs in early-type galaxies—II. Photometric properties,” Monthly Notices of the Royal Astronomical Society, vol. 300, no. 2, pp. 469–478, 1998.
[78]
K. Gebhardt and J. Thomas, “The black hole mass, stellar mass-to-light ratio, and Dark Halo in m87,” Astrophysical Journal Letters, vol. 700, no. 2, pp. 1690–1701, 2009.
[79]
P. J. Young, J. A. Westphal, J. Kristian, C. P. Wilson, and F. P. Landauer, “Evidence for a supermassive object in the nucleus of the galaxy M87 from SIT and CCD area photometry,” Astrophysical Journal, vol. 221, pp. 721–730, 1978.
[80]
G. A. Bower, R. F. Green, A. C. Quillen et al., “The ionization source in the nucleus of M84,” Astrophysical Journal Letters, vol. 534, no. 1, pp. 189–200, 2000.
[81]
J. L. Walsh, A. J. Barth, and M. Sarzi, “The supermassive black hole in M84 revisited,” Astrophysical Journal Letters, vol. 721, no. 1, pp. 762–776, 2010.
[82]
L. Ferrarese, H. C. Ford, and W. Jaffe, “Evidence for a massive black hole in the active galaxy NGC 4261 from bubble space telescope images and spectra,” Astrophysical Journal Letters, vol. 470, no. 1, pp. 444–459, 1996.
[83]
S. P. Rusli, J. Thomas, P. Erwin, R. P. Saglia, N. Nowak, and R. Bender, “The central black hole mass of the high-σ but low-bulge-luminosity lenticular galaxy NGC 1332,” Monthly Notices of the Royal Astronomical Society, vol. 410, no. 2, pp. 1223–1236, 2011.
[84]
N. Devereux, H. Ford, Z. Tsvetanov, and G. Jacoby, “STIS spectroscopy of the central 10 parsecs of M81: evidence for a massive black hole,” Astronomical Journal, vol. 125, no. 3, pp. 1226–1235, 2003.
[85]
M. J. Jee, J. P. Blakeslee, M. Sirianni, A. R. Martel, R. L. White, and H. C. Ford, “Principal component analysis of the time- and position-dependent point-spread function of the advanced camera for surveys,” Publications of the Astronomical Society of the Pacific, vol. 119, no. 862, pp. 1403–1409, 2007.
[86]
L. Ferrarese, P. C？té, A. Jordán et al., “The ACS Virgo Cluster survey. VI. Isophotal analysis and the structure of early-type galaxies,” Astrophysical Journal, Supplement Series, vol. 164, no. 2, pp. 334–434, 2006.
[87]
T. R. Lauer, K. Gebhardt, S. M. Faber et al., “The centers of early-type galaxies with Hubble Space Telescope. VI. Bimodal central surface brightness profiles,” Astrophysical Journal, vol. 664, no. 1, pp. 226–256, 2007.
[88]
G. De Francesco, A. Capetti, and A. Marconi, “Measuring supermassive black holes with gas kinematics: the active so galaxy NGC 3998,” Astronomy and Astrophysics, vol. 460, no. 2, pp. 439–448, 2006.
[89]
N. Cretton and F. C. Van Den Bosch, “Evidence for a massive black hole in the S0 galaxy NGC 4342,” Astrophysical Journal Letters, vol. 514, no. 2, pp. 704–724, 1999.
[90]
K. Gebhardt, D. Richstone, J. Kormendy et al., “Axisymmetric, three-integral models of galaxies: a massive black hole in NGC 3379,” Astronomical Journal, vol. 119, no. 3, pp. 1157–1171, 2000.
[91]
D. Merritt and A. Szell, “Dynamical cusp regeneration,” Astrophysical Journal, vol. 648, no. 2, pp. 890–899, 2006.
[92]
M. Koleva, P. Prugniel, S. De Rijcke, and W. W. Zeilinger, “Age and metallicity gradients in early-type galaxies: a dwarf-to-giant sequence,” Monthly Notices of the Royal Astronomical Society, vol. 417, no. 3, pp. 1643–1671, 2011.
[93]
H. Zinnecker, C. J. Keable, J. S. Dunlop, R. D. Cannon, and W. K. Griths, “The harlow-shapley symposium on globular cluster systems in galaxies,” in Proceedings of the 126th Symposium of the International Astronomical Union (IAU '88), J. E. Grindlay and A. G. D. Philip, Eds., vol. 126, p. 603, 1988.
[94]
K. C. Freeman, The Globular Cluster-Galaxy Connection, vol. 48 of Astronomical Society of the Pacific Conference Series, 1993, edited by G. H. Smith and J. P. Brodie.
[95]
K. Bekki and K. C. Freeman, “Formation of ω Centauri from an ancient nucleated dwarf galaxy in the young Galactic disc,” Monthly Notices of the Royal Astronomical Society, vol. 346, no. 2, pp. L11–L15, 2003.
[96]
T. B？ker, “Are globular clusters the remnant nuclei of progenitor disk galaxies?” Astrophysical Journal Letters, vol. 672, no. 2, pp. L111–L114, 2008.
[97]
M. Milosavljevi？, “On the origin of nuclear star clusters in late-type spiral galaxies,” Astrophysical Journal Letters, vol. 605, no. 1, pp. L13–L16, 2004.
[98]
K. Bekki, W. J. Couch, and Y. Shioya, “Dissipative transformation of nonnucleated dwarf galaxies into nucleated systems,” Astrophysical Journal Letters, vol. 642, no. 2, pp. L133–L136, 2006.
[99]
J. Pflamm-Altenburg and P. Kroupa, “Recurrent gas accretion by massive star clusters, multiple stellar populations and mass thresholds for spheroidal stellar systems,” Monthly Notices of the Royal Astronomical Society, vol. 397, no. 1, pp. 488–494, 2009.
[100]
S. D. Tremaine, J. P. Ostriker, and L. Spitzer, “The formation of the nuclei of galaxies. I—M31,” Astrophysical Journal, vol. 196, pp. 407–411, 1975.
[101]
R. Capuzzo-Dolcetta, “The evolution of the globular cluster system in a triaxial galaxy: can a galactic nucleus form by globular cluster capture?” Astrophysical Journal Letters, vol. 415, no. 2, pp. 616–630, 1993.
[102]
D. E. Mclaughlin, “Was the compact nucleus in M87 formed by destroyed globular clusters?” Astronomical Journal, vol. 109, no. 5, pp. 2034–2037, 1995.
[103]
K. Bekki, W. J. Couch, M. J. Drinkwater, and Y. Shioya, “Cluster cannibalism and scaling relations of galactic stellar nuclei,” Astrophysical Journal Letters, vol. 610, no. 1, pp. L13–L16, 2004.
[104]
P. Miocchi, R. C. Dolcetta, P. Di Matteo, and A. Vicari, “Merging of globular clusters in inner galactic regions. I. Do they survive the tidal interaction?” Astrophysical Journal Letters, vol. 644, no. 2, pp. 940–953, 2006.
[105]
M. Agarwal and M. Milosavljevi？, “Nuclear star clusters from clustered star formation,” Astrophysical Journal Letters, vol. 729, article 35, 2011.
[106]
S. Nayakshin, M. I. Wilkinson, and A. King, “Competitive feedback in galaxy formation,” Monthly Notices of the Royal Astronomical Society, vol. 398, no. 1, pp. L54–L57, 2009.
[107]
D. Merritt, “Dynamics of galaxy cores and supermassive black holes,” Reports on Progress in Physics, vol. 69, no. 9, pp. 2513–2579, 2006.
[108]
K. Bekki and A. W. Graham, “On the transition from nuclear-cluster- to black-hole-dominated galaxy cores,” Astrophysical Journal Letters, vol. 714, no. 2, pp. L313–L317, 2010.
[109]
K. Gebhardt, J. Adams, D. Richstone et al., “The black hole mass in M87 from Gemini/NIFS adaptive optics observations,” Astrophysical Journal Letters, vol. 729, article 119, 2011.
[110]
G. A. Bower, R. F. Green, A. Danks et al., “Kinematics of the nuclear ionized gas in the radio galaxy M84 (NGC 4374),” Astrophysical Journal Letters, vol. 492, no. 2, pp. L111–L114, 1998.
[111]
K. Gebhardt, D. Richstone, S. Tremaine et al., “Axisymmetric dynamical models of the central regions of galaxies,” Astrophysical Journal Letters, vol. 583, no. 1, pp. 92–115, 2003.
[112]
M. Sarzi, H.-W. Rix, J. C. Shields et al., “Supermassive black holes in bulges,” Astrophysical Journal Letters, vol. 550, no. 1, pp. 65–74, 2001.
[113]
K. L. Shapiro, M. Cappellari, T. De Zeeuw et al., “The black hole in NGC 3379: a comparison of gas and stellar dynamical mass measurements with HST and integral-field data,” Monthly Notices of the Royal Astronomical Society, vol. 370, no. 2, pp. 559–579, 2006.
