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Title: The MASSIVE Survey. XVII. A Triaxial Orbit-based Determination of the Black Hole Mass and Intrinsic Shape of Elliptical Galaxy NGC 2693

We present a stellar dynamical mass measurement of a newly detected supermassive black hole (SMBH) at the center of the fast-rotating, massive elliptical galaxy NGC 2693 as part of the MASSIVE survey. We combine high signal-to-noise ratio integral field spectroscopy (IFS) from the Gemini Multi-Object Spectrograph with wide-field data from the Mitchell Spectrograph at McDonald Observatory to extract and model stellar kinematics of NGC 2693 from the central ∼150 pc out to ∼2.5 effective radii. Observations from Hubble Space Telescope WFC3 are used to determine the stellar light distribution. We perform fully triaxial Schwarzschild orbit modeling using the latest TriOS code and a Bayesian search in 6D galaxy model parameter space to determine NGC 2693's SMBH mass (MBH), stellar mass-to-light ratio, dark matter content, and intrinsic shape. We findMBH=1.7±0.4×109Mand a triaxial intrinsic shape with axis ratiosp=b/a= 0.902 ± 0.009 andq=c/a=0.7210.010+0.011, triaxiality parameterT= 0.39 ± 0.04. In comparison, the best-fit orbit model in the axisymmetric limit and (cylindrical) Jeans anisotropic model of NGC 2693 preferMBH=2.4±0.6×109MandMBH=2.9±0.3×109M, respectively. Neither model can account for the non-axisymmetric stellar velocity features present in more » the IFS data.

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Award ID(s):
1814799 1817100
Publication Date:
Journal Name:
The Astrophysical Journal
Page Range or eLocation-ID:
Article No. 178
DOI PREFIX: 10.3847
Sponsoring Org:
National Science Foundation
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