[ITAL]Hubble Space Telescope[/ITAL] Evidence for an Intermediate-Mass Black Hole in the Globular Cluster M15. II. Kinematic Analysis and Dynamical Modeling

Gerssen, J.; Marel, Roeland P. van der; Gebhardt, Karl; Guhathakurta, Puragra; Peterson, R. C.; Pryor, C.

doi:10.1086/344584

Cited by 249 publications

(318 citation statements)

References 68 publications

Supporting

Mentioning

296

Contrasting

Unclassified

Order By: Relevance

“…For example, Gerssen et al (2002) found in their study of M 15 that the necessity for a black hole was diminished when a varying M/L was assumed, which in this case was obtained from FokkerPlanck simulations. These simulations predicted a rise in the central M/L, mainly caused by the segregation of stellar remnants near the centre.…”

Section: Jeans Modellingmentioning

confidence: 96%

See 1 more Smart Citation

MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397

Kamann

Husser

Brinchmann

et al. 2016

A&A

View full text Add to dashboard Cite

We present a detailed analysis of the kinematics of the Galactic globular cluster NGC 6397 based on more than ∼18 000 spectra obtained with the novel integral field spectrograph MUSE. While NGC 6397 is often considered a core collapse cluster, our analysis suggests a flattening of the surface brightness profile at the smallest radii. Although it is among the nearest globular clusters, the low velocity dispersion of NGC 6397 of <5 km s −1 imposes heavy demands on the quality of the kinematical data. We show that despite its limited spectral resolution, MUSE reaches an accuracy of 1 km s −1 in the analysis of stellar spectra. We find slight evidence for a rotational component in the cluster and the velocity dispersion profile that we obtain shows a mild central cusp. To investigate the nature of this feature, we calculate spherical Jeans models and compare these models to our kinematical data. This comparison shows that if a constant mass-to-light ratio is assumed, the addition of an intermediate-mass black hole with a mass of 600 M brings the model predictions into agreement with our data, and therefore could be at the origin of the velocity dispersion profile. We further investigate cases with varying mass-to-light ratios and find that a compact dark stellar component can also explain our observations. However, such a component would closely resemble the black hole from the constant mass-to-light ratio models as this component must be confined to the central ∼5 of the cluster and must have a similar mass. Independent constraints on the distribution of stellar remnants in the cluster or kinematic measurements at the highest possible spatial resolution should be able to distinguish the two alternatives.

show abstract

Section: Jeans Modellingmentioning

confidence: 96%

“…To compare the model predictions of the velocity dispersion to our measurements, we used the same maximum-likelihood approach as in Gerssen et al (2002) and Kamann et al (2014). This approach has the advantage that it does not require any binning of the data.…”

Section: Jeans Modellingmentioning

confidence: 99%

MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397

Kamann

Husser

Brinchmann

et al. 2016

A&A

View full text Add to dashboard Cite

show abstract

“…However, recent observations (e.g. Gebhardt et al 2000;Gerssen et al 2002;Gebhardt et al 2005;Noyola et al 2008;Lützgendorf et al 2011) have shown that the velocity-dispersion profiles of some globular clusters and dwarf galaxies are consistent with hosting a massive black hole at their center.…”

Section: Introductionmentioning

confidence: 99%

Central kinematics of the globular cluster NGC 2808: upper limit on the mass of an intermediate-mass black hole

Lützgendorf

Kissler-Patig

Gebhardt

et al. 2012

A&A

View full text Add to dashboard Cite

Context. Globular clusters are an excellent laboratory for stellar population and dynamical research. Recent studies have shown that these stellar systems are not as simple as previously assumed. With multiple stellar populations as well as outer rotation and mass segregation they turn out to exhibit high complexity. This includes intermediate-mass black holes (IMBHs) which are proposed to sit at the centers of some massive globular clusters. Today's high angular resolution ground based spectrographs allow velocity-dispersion measurements at a spatial resolution comparable to the radius of influence for plausible IMBH masses, and to detect changes in the inner velocity-dispersion profile. Together with high quality photometric data from HST, it is possible to constrain black-hole masses by their kinematic signatures. Aims. We determine the central velocity-dispersion profile of the globular cluster NGC 2808 using VLT/FLAMES spectroscopy. In combination with HST/ACS data our goal is to probe whether this massive cluster hosts an IMBH at its center and constrain the cluster mass to light ratio as well as its total mass. Methods. We derive a velocity-dispersion profile from integral field spectroscopy in the center and Fabry Perot data for larger radii. High resolution HST data are used to obtain the surface brightness profile. Together, these data sets are compared to dynamical models with varying parameters such as mass to light ratio profiles and black-hole masses. Results. Using analytical Jeans models in combination with variable M/L V profiles from N-body simulations we find that the best fit model is a no black hole solution. After applying various Monte Carlo simulations to estimate the uncertainties, we derive an upper limit of the back hole mass of M BH < 1 × 10 4 M (with 95% confidence limits) and a global mass-to-light ratio of M/L V = (2.1 ± 0.2) M /L .

show abstract

“…DATA Gerssen et al (2002) present radial velocities of 64 stars obtained by the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST ). This sample of stars is characterized by very high spatial resolution; the smallest radius at which kinematic information is available in the sample (r min ) is only about 0.01 pc.…”

Section: Introductionmentioning

confidence: 99%

An Inverse Look at the Center of M15

Chakrabarty

2006

Astron J

View full text Add to dashboard Cite

The observed radial and transverse velocities of individual stars in the globular cluster M15 are used as inputs to a fully nonparametric code (CHASSIS) in order to estimate the equilibrium stellar distribution function and the threedimensional mass density profile, from which are estimated the mass-to-light ratio, enclosed mass, and velocity dispersion profiles. In particular, the paper explores the possible existence of a central black hole in M15 via several runs that use the radial velocity data set, which offers kinematic measurements closer to the center of the cluster than the proper-motion data. These runs are distinguished from each other in the choice of the initial seed for the cluster characteristics; however, the profiles identified by the algorithm at the end of each run concur with each other within error bars, thus confirming the robustness of CHASSIS. The recovered density profiles are noted to exhibit unequivocal flattening interior to about 0.0525 pc. Also, the enclosed mass profile is very close to being a power-law function of radius <0.1 pc and is not horizontal. Simplistically speaking, these trends negate the possibility of the central mass being concentrated in a black hole, the lower bound on the radius of the sphere of influence of which would be k0.041 pc had it existed. However, proper analysis suggests that the mass enclosed within the inner 0.01 pc could be in the form of a black hole of mass $10 3 M under two different scenarios, which are discussed. The line-ofsight velocity dispersion is visually found to be very similar to the observed dispersion profile. The enclosed mass and velocity dispersion profiles calculated from runs done with the proper-motion data are found to be consistent with the profiles obtained with the radial velocity data.

show abstract

[ITAL]Hubble Space Telescope[/ITAL] Evidence for an Intermediate-Mass Black Hole in the Globular Cluster M15. II. Kinematic Analysis and Dynamical Modeling

Cited by 249 publications

References 68 publications

MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397

MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397

Central kinematics of the globular cluster NGC 2808: upper limit on the mass of an intermediate-mass black hole

An Inverse Look at the Center of M15

Contact Info

Product

Resources

About