The MASSIVE Survey. XX. A Triaxial Stellar Dynamical Measurement of the Supermassive Black Hole Mass and Intrinsic Galaxy Shape of Giant Radio Galaxy NGC 315
We present a new dynamical measurement of the supermassive black hole mass and intrinsic shape of the stellar halo of the massive radio galaxy NGC 315 as part of the MASSIVE survey. High signal-to-noise ratio spectra from integral-field spectrographs at the Gemini and McDonald Observatories provide...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/adee1e |
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| author | Jacob Pilawa Emily R. Liepold Chung-Pei Ma Jonelle L. Walsh Jenny E. Greene |
| author_facet | Jacob Pilawa Emily R. Liepold Chung-Pei Ma Jonelle L. Walsh Jenny E. Greene |
| author_sort | Jacob Pilawa |
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| description | We present a new dynamical measurement of the supermassive black hole mass and intrinsic shape of the stellar halo of the massive radio galaxy NGC 315 as part of the MASSIVE survey. High signal-to-noise ratio spectra from integral-field spectrographs at the Gemini and McDonald Observatories provide stellar kinematic measurements in 304 spatial bins from the central $\sim 0\mathop{.}\limits^{^{\prime\prime} }3$ out to 30 ^″ . Using ∼2300 kinematic constraints, we perform triaxial stellar orbit modeling with the TriOS code and search over ∼15,000 galaxy models with a Bayesian scheme to simultaneously measure six mass and intrinsic shape parameters. NGC 315 is triaxial and highly prolate, with middle-to-long and short-to-long axis ratios of p = 0.854 and q = 0.833, and a triaxiality parameter of T = 0.89. The black hole mass inferred from our stellar kinematics is ${M}_{{\rm{BH}}}=\left(3.0\pm 0.3\right)\times 1{0}^{9}\,{M}_{\odot }$ , which is higher than ${M}_{{\rm{BH}}}=(1.9{6}_{-0.13}^{+0.30})\times 1{0}^{9}{M}_{\odot }$ inferred from CO kinematics (scaled to our distance). When the seven galaxies with M _BH measurements from both stellar and CO kinematics are compared, we find an intrinsic scatter of 0.28 dex in M _BH from the two tracers and do not detect statistically significant biases between the two methods in the current data. The implied black hole shadow size (≈4.7 μ as) and the relatively high millimeter flux of NGC 315 makes this galaxy a prime candidate for future horizon-size imaging studies. |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-b54524c111bb42d4af202532ea18e67c2025-08-20T03:39:36ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198919810.3847/1538-4357/adee1eThe MASSIVE Survey. XX. A Triaxial Stellar Dynamical Measurement of the Supermassive Black Hole Mass and Intrinsic Galaxy Shape of Giant Radio Galaxy NGC 315Jacob Pilawa0https://orcid.org/0000-0001-7040-9117Emily R. Liepold1https://orcid.org/0000-0002-7703-7077Chung-Pei Ma2https://orcid.org/0000-0002-4430-102XJonelle L. Walsh3https://orcid.org/0000-0002-1881-5908Jenny E. Greene4https://orcid.org/0000-0002-5612-3427Department of Astronomy, University of California , Berkeley, CA 94720, USA ; jacobpilawa@berkeley.eduDepartment of Astronomy, University of California , Berkeley, CA 94720, USA ; jacobpilawa@berkeley.eduDepartment of Astronomy, University of California , Berkeley, CA 94720, USA ; jacobpilawa@berkeley.edu; Department of Physics, University of California , Berkeley, CA 94720, USAGeorge P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A&M University , College Station, TX 77843, USADepartment of Astrophysical Sciences, Princeton University , Princeton, NJ 08544, USAWe present a new dynamical measurement of the supermassive black hole mass and intrinsic shape of the stellar halo of the massive radio galaxy NGC 315 as part of the MASSIVE survey. High signal-to-noise ratio spectra from integral-field spectrographs at the Gemini and McDonald Observatories provide stellar kinematic measurements in 304 spatial bins from the central $\sim 0\mathop{.}\limits^{^{\prime\prime} }3$ out to 30 ^″ . Using ∼2300 kinematic constraints, we perform triaxial stellar orbit modeling with the TriOS code and search over ∼15,000 galaxy models with a Bayesian scheme to simultaneously measure six mass and intrinsic shape parameters. NGC 315 is triaxial and highly prolate, with middle-to-long and short-to-long axis ratios of p = 0.854 and q = 0.833, and a triaxiality parameter of T = 0.89. The black hole mass inferred from our stellar kinematics is ${M}_{{\rm{BH}}}=\left(3.0\pm 0.3\right)\times 1{0}^{9}\,{M}_{\odot }$ , which is higher than ${M}_{{\rm{BH}}}=(1.9{6}_{-0.13}^{+0.30})\times 1{0}^{9}{M}_{\odot }$ inferred from CO kinematics (scaled to our distance). When the seven galaxies with M _BH measurements from both stellar and CO kinematics are compared, we find an intrinsic scatter of 0.28 dex in M _BH from the two tracers and do not detect statistically significant biases between the two methods in the current data. The implied black hole shadow size (≈4.7 μ as) and the relatively high millimeter flux of NGC 315 makes this galaxy a prime candidate for future horizon-size imaging studies.https://doi.org/10.3847/1538-4357/adee1eGalaxiesSupermassive black holesStellar dynamicsGalaxy evolutionDark matterElliptical galaxies |
| spellingShingle | Jacob Pilawa Emily R. Liepold Chung-Pei Ma Jonelle L. Walsh Jenny E. Greene The MASSIVE Survey. XX. A Triaxial Stellar Dynamical Measurement of the Supermassive Black Hole Mass and Intrinsic Galaxy Shape of Giant Radio Galaxy NGC 315 The Astrophysical Journal Galaxies Supermassive black holes Stellar dynamics Galaxy evolution Dark matter Elliptical galaxies |
| title | The MASSIVE Survey. XX. A Triaxial Stellar Dynamical Measurement of the Supermassive Black Hole Mass and Intrinsic Galaxy Shape of Giant Radio Galaxy NGC 315 |
| title_full | The MASSIVE Survey. XX. A Triaxial Stellar Dynamical Measurement of the Supermassive Black Hole Mass and Intrinsic Galaxy Shape of Giant Radio Galaxy NGC 315 |
| title_fullStr | The MASSIVE Survey. XX. A Triaxial Stellar Dynamical Measurement of the Supermassive Black Hole Mass and Intrinsic Galaxy Shape of Giant Radio Galaxy NGC 315 |
| title_full_unstemmed | The MASSIVE Survey. XX. A Triaxial Stellar Dynamical Measurement of the Supermassive Black Hole Mass and Intrinsic Galaxy Shape of Giant Radio Galaxy NGC 315 |
| title_short | The MASSIVE Survey. XX. A Triaxial Stellar Dynamical Measurement of the Supermassive Black Hole Mass and Intrinsic Galaxy Shape of Giant Radio Galaxy NGC 315 |
| title_sort | massive survey xx a triaxial stellar dynamical measurement of the supermassive black hole mass and intrinsic galaxy shape of giant radio galaxy ngc 315 |
| topic | Galaxies Supermassive black holes Stellar dynamics Galaxy evolution Dark matter Elliptical galaxies |
| url | https://doi.org/10.3847/1538-4357/adee1e |
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