skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The black hole mass and the stellar ring in NGC 3706

Abstract

We determine the mass of the nuclear black hole (M) in NGC 3706, an early-type galaxy with a central surface brightness minimum arising from an apparent stellar ring, which is misaligned with respect to the galaxy's major axis at larger radii. We fit new HST/STIS and archival data with axisymmetric orbit models to determine M, mass-to-light ratio (Y {sub V}), and dark matter halo profile. The best-fit model parameters with 1σ uncertainties are M=(6.0{sub −0.9}{sup +0.7})×10{sup 8} M{sub ⊙} and Υ{sub V}=6.0±0.2 M{sub ⊙} L{sub ⊙,V}{sup −1} at an assumed distance of 46 Mpc. The models are inconsistent with no black hole at a significance of Δχ{sup 2} = 15.4 and require a dark matter halo to adequately fit the kinematic data, but the fits are consistent with a large range of plausible dark matter halo parameters. The ring is inconsistent with a population of co-rotating stars on circular orbits, which would produce a narrow line-of-sight velocity distribution (LOSVD). Instead, the ring's LOSVD has a small value of |V|/σ, the ratio of mean velocity to velocity dispersion. Based on the observed low |V|/σ, our orbit modeling, and a kinematic decomposition of the ring from the bulge, we conclude that themore » stellar ring contains stars that orbit in both directions. We consider potential origins for this unique feature, including multiple tidal disruptions of stellar clusters, a change in the gravitational potential from triaxial to axisymmetric, resonant capture and inclining of orbits by a binary black hole, and multiple mergers leading to gas being funneled to the center of the galaxy.« less

Authors:
;  [1]; ;  [2];  [3];  [4];  [5]
  1. Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)
  2. Department of Astronomy, University of Texas, 1 University Station C1400, Austin, TX 78712 (United States)
  3. National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726 (United States)
  4. Universitäts-Sternwarte München, Ludwig-Maximilians-Universität, Scheinerstr. 1, D-81679 München (Germany)
  5. Institute for Advanced Study, Einstein Dr., Princeton, NJ 08540 (United States)
Publication Date:
OSTI Identifier:
22348096
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 781; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AXIAL SYMMETRY; BLACK HOLES; CAPTURE; DECOMPOSITION; DISPERSIONS; DISTANCE; DISTRIBUTION; GALAXIES; GALAXY NUCLEI; MASS; NONLUMINOUS MATTER; ORBITS; ORIGIN; SIMULATION; STARS; VELOCITY; VISIBLE RADIATION

Citation Formats

Gültekin, Kayhan, Richstone, Douglas O., Gebhardt, Karl, Kormendy, John, Lauer, Tod R., Bender, Ralf, and Tremaine, Scott, E-mail: kayhan@umich.edu. The black hole mass and the stellar ring in NGC 3706. United States: N. p., 2014. Web. doi:10.1088/0004-637X/781/2/112.
Gültekin, Kayhan, Richstone, Douglas O., Gebhardt, Karl, Kormendy, John, Lauer, Tod R., Bender, Ralf, & Tremaine, Scott, E-mail: kayhan@umich.edu. The black hole mass and the stellar ring in NGC 3706. United States. doi:10.1088/0004-637X/781/2/112.
Gültekin, Kayhan, Richstone, Douglas O., Gebhardt, Karl, Kormendy, John, Lauer, Tod R., Bender, Ralf, and Tremaine, Scott, E-mail: kayhan@umich.edu. Sat . "The black hole mass and the stellar ring in NGC 3706". United States. doi:10.1088/0004-637X/781/2/112.
@article{osti_22348096,
title = {The black hole mass and the stellar ring in NGC 3706},
author = {Gültekin, Kayhan and Richstone, Douglas O. and Gebhardt, Karl and Kormendy, John and Lauer, Tod R. and Bender, Ralf and Tremaine, Scott, E-mail: kayhan@umich.edu},
abstractNote = {We determine the mass of the nuclear black hole (M) in NGC 3706, an early-type galaxy with a central surface brightness minimum arising from an apparent stellar ring, which is misaligned with respect to the galaxy's major axis at larger radii. We fit new HST/STIS and archival data with axisymmetric orbit models to determine M, mass-to-light ratio (Y {sub V}), and dark matter halo profile. The best-fit model parameters with 1σ uncertainties are M=(6.0{sub −0.9}{sup +0.7})×10{sup 8} M{sub ⊙} and Υ{sub V}=6.0±0.2 M{sub ⊙} L{sub ⊙,V}{sup −1} at an assumed distance of 46 Mpc. The models are inconsistent with no black hole at a significance of Δχ{sup 2} = 15.4 and require a dark matter halo to adequately fit the kinematic data, but the fits are consistent with a large range of plausible dark matter halo parameters. The ring is inconsistent with a population of co-rotating stars on circular orbits, which would produce a narrow line-of-sight velocity distribution (LOSVD). Instead, the ring's LOSVD has a small value of |V|/σ, the ratio of mean velocity to velocity dispersion. Based on the observed low |V|/σ, our orbit modeling, and a kinematic decomposition of the ring from the bulge, we conclude that the stellar ring contains stars that orbit in both directions. We consider potential origins for this unique feature, including multiple tidal disruptions of stellar clusters, a change in the gravitational potential from triaxial to axisymmetric, resonant capture and inclining of orbits by a binary black hole, and multiple mergers leading to gas being funneled to the center of the galaxy.},
doi = {10.1088/0004-637X/781/2/112},
journal = {Astrophysical Journal},
number = 2,
volume = 781,
place = {United States},
year = {Sat Feb 01 00:00:00 EST 2014},
month = {Sat Feb 01 00:00:00 EST 2014}
}
  • We present a new stellar dynamical mass measurement of the black hole in the nearby, S0 galaxy NGC 3998. By combining laser guide star adaptive optics observations obtained with the OH-Suppressing Infrared Imaging Spectrograph on the Keck II telescope with long-slit spectroscopy from the Hubble Space Telescope and the Keck I telescope, we map out the stellar kinematics on both small spatial scales, well within the black hole sphere of influence, and large scales. We find that the galaxy is rapidly rotating and exhibits a sharp central peak in the velocity dispersion. Using the kinematics and the stellar luminosity densitymore » derived from imaging observations, we construct three-integral, orbit-based, triaxial stellar dynamical models. We find the black hole has a mass of M{sub BH} = (8.1{sup +2.0}{sub -1.9}) Multiplication-Sign 10{sup 8} M{sub Sun }, with an I-band stellar mass-to-light ratio of M/L = 5.0{sup +0.3}{sub -0.4} M{sub Sun }/L{sub Sun} (3{sigma} uncertainties), and that the intrinsic shape of the galaxy is very round, but oblate. With the work presented here, NGC 3998 is now one of a very small number of galaxies for which both stellar and gas dynamical modeling have been used to measure the mass of the black hole. The stellar dynamical mass is nearly a factor of four larger than the previous gas dynamical black hole mass measurement. Given that this cross-check has so far only been attempted on a few galaxies with mixed results, carrying out similar studies in other objects is essential for quantifying the magnitude and distribution of the cosmic scatter in the black hole mass-host galaxy relations.« less
  • We present a revised measurement of the mass of the central black hole (M{sub BH} ) in the Seyfert 1 galaxy NGC 4151. The new stellar dynamical mass measurement is derived by applying an axisymmetric orbit-superposition code to near-infrared integral field data obtained using adaptive optics with the Gemini Near-infrared Integral Field Spectrograph (NIFS). When our models attempt to fit both the NIFS kinematics and additional low spatial resolution kinematics, our results depend sensitively on how χ{sup 2} is computed—probably a consequence of complex bar kinematics that manifest immediately outside the nuclear region. The most robust results are obtained whenmore » only the high spatial resolution kinematic constraints in the nuclear region are included in the fit. Our best estimates for the black hole mass and H-band mass-to-light ratio are M{sub BH} ∼ 3.76 ± 1.15 × 10{sup 7} M{sub ☉} (1σ error) and Y{sub H} ∼ 0.34 ± 0.03 M{sub ☉}/L{sub ☉} (3σ error), respectively (the quoted errors reflect the model uncertainties). Our black hole mass measurement is consistent with estimates from both reverberation mapping (3.57{sub −0.37}{sup +0.45}×10{sup 7} M{sub ⊙}) and gas kinematics (3.0{sub −2.2}{sup +0.75}×10{sup 7} M{sub ⊙}; 1σ errors), and our best-fit mass-to-light ratio is consistent with the photometric estimate of Y{sub H} = 0.4 ± 0.2 M{sub ☉}/L{sub ☉}. The NIFS kinematics give a central bulge velocity dispersion σ{sub c} = 116 ± 3 km s{sup –1}, bringing this object slightly closer to the M{sub BH}-σ relation for quiescent galaxies. Although NGC 4151 is one of only a few Seyfert 1 galaxies in which it is possible to obtain a direct dynamical black hole mass measurement—and thus, an independent calibration of the reverberation mapping mass scale—the complex bar kinematics makes it less than ideally suited for this purpose.« less
  • We study two nearby early-type galaxies, NGC 4342 and NGC 4291, that host unusually massive black holes relative to their low stellar mass. The observed black-hole-to-bulge mass ratios of NGC 4342 and NGC 4291 are 6.9{sup +3.8}{sub -2.3}% and 1.9% {+-} 0.6%, respectively, which significantly exceed the typical observed ratio of {approx}0.2%. As a consequence of the exceedingly large black-hole-to-bulge mass ratios, NGC 4342 and NGC 4291 are Almost-Equal-To 5.1{sigma} and Almost-Equal-To 3.4{sigma} outliers from the M{sub .}-M{sub bulge} scaling relation, respectively. In this paper, we explore the origin of the unusually high black-hole-to-bulge mass ratio. Based on Chandra X-raymore » observations of the hot gas content of NGC 4342 and NGC 4291, we compute gravitating mass profiles, and conclude that both galaxies reside in massive dark matter halos, which extend well beyond the stellar light. The presence of dark matter halos around NGC 4342 and NGC 4291 and a deep optical image of the environment of NGC 4342 indicate that tidal stripping, in which {approx}> 90% of the stellar mass was lost, cannot explain the observed high black-hole-to-bulge mass ratios. Therefore, we conclude that these galaxies formed with low stellar masses, implying that the bulge and black hole did not grow in tandem. We also find that the black hole mass correlates well with the properties of the dark matter halo, suggesting that dark matter halos may play a major role in regulating the growth of the supermassive black holes.« less
  • Theoretical investigations have suggested the presence of intermediate mass black holes (IMBHs, with masses in the 100-10000 M{sub sun} range) in the cores of some globular clusters (GCs). In this paper, we present the first application of a new technique to determine the presence or absence of a central IMBH in globular clusters that have reached energy equipartition via two-body relaxation. The method is based on the measurement of the radial profile for the average mass of stars in the system, using the fact that a quenching of mass segregation is expected when an IMBH is present. Here, we measuremore » the radial profile of mass segregation using main-sequence stars for the globular cluster NGC 2298 from resolved source photometry based on Hubble Space Telescope (HST/ACS) data. NGC 2298 is one of the smallest galactic globular clusters, thus not only it is dynamically relaxed but also a single ACS field of view extends to about twice its half-light radius, providing optimal radial coverage. The observations are compared to expectations from direct N-body simulations of the dynamics of star clusters with and without an IMBH. The mass segregation profile for NGC 2298 is quantitatively matched to that inferred from simulations without a central massive object over all the radial range probed by the observations, that is from the center to about two half-mass radii. Profiles from simulations containing an IMBH more massive than {approx}300-500 M{sub sun} (depending on the assumed total mass of NGC 2298) are instead inconsistent with the data at about 3{sigma} confidence, irrespective of the initial mass function and binary fraction chosen for these runs. Our finding is consistent with the currently favored formation scenarios for IMBHs in GCs, which are not likely to apply to NGC 2298 due to its modest total mass. While providing a null result in the quest of detecting a central black hole in globular clusters, the data-model comparison carried out here demonstrates the feasibility of the method which can also be applied to other globular clusters with resolved photometry in their cores.« less
  • We model the dynamical structure of M87 (NGC4486) using high spatial resolution long-slit observations of stellar light in the central regions, two-dimensional stellar light kinematics out to half of the effective radius, and globular cluster velocities out to eight effective radii. We simultaneously fit for four parameters: black hole mass, dark halo core radius, dark halo circular velocity, and stellar mass-to-light (M/L) ratio. We find a black hole mass of 6.4({+-}0.5) x 10{sup 9} M {sub sun} (the uncertainty is 68% confidence marginalized over the other parameters). The stellar M/L{sub V} = 6.3 {+-} 0.8. The best-fit dark halo coremore » radius is 14 {+-} 2 kpc, assuming a cored logarithmic potential. The best-fit dark halo circular velocity is 715 {+-} 15 km s{sup -1}. Our black hole mass is over a factor of 2 larger than previous stellar dynamical measures, and our derived stellar M/L ratio is two times lower than previous dynamical measures. When we do not include a dark halo, we measure a black hole mass and stellar M/L ratio that is consistent with previous measures, implying that the major difference is in the model assumptions. The stellar M/L ratio from our models is very similar to that derived from stellar population models of M87. The reason for the difference in the black hole mass is because we allow the M/L ratio to change with radius. The dark halo is degenerate with the stellar M/L ratio, which is subsequently degenerate with the black hole mass. We argue that dynamical models of galaxies that do not include the contribution from a dark halo may produce a biased result for the black hole mass. This bias is especially large for a galaxy with a shallow light profile such as M87, and may not be as severe in galaxies with steeper light profiles unless they have a large stellar population change with radius.« less