Rotation in Event Horizon Telescope Movies
The Event Horizon Telescope (EHT) has produced images of M87* and Sagittarius A*, and will soon produce time sequences of images, or movies. In anticipation of this, we describe a technique to measure the rotation rate, or pattern speed Ω _p , from movies using an autocorrelation technique. We valid...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acd2c8 |
| _version_ | 1797699422708039680 |
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| author | Nicholas S. Conroy Michi Bauböck Vedant Dhruv Daeyoung Lee Avery E. Broderick Chi-kwan Chan Boris Georgiev Abhishek V. Joshi Ben Prather Charles F. Gammie |
| author_facet | Nicholas S. Conroy Michi Bauböck Vedant Dhruv Daeyoung Lee Avery E. Broderick Chi-kwan Chan Boris Georgiev Abhishek V. Joshi Ben Prather Charles F. Gammie |
| author_sort | Nicholas S. Conroy |
| collection | DOAJ |
| description | The Event Horizon Telescope (EHT) has produced images of M87* and Sagittarius A*, and will soon produce time sequences of images, or movies. In anticipation of this, we describe a technique to measure the rotation rate, or pattern speed Ω _p , from movies using an autocorrelation technique. We validate the technique on Gaussian random field models with a known rotation rate and apply it to a library of synthetic images of Sgr A* based on general relativistic magnetohydrodynamics simulations. We predict that EHT movies will have Ω _p ≈ 1° per GMc ^−3 , which is of order 15% of the Keplerian orbital frequency in the emitting region. We can plausibly attribute the slow rotation seen in our models to the pattern speed of inward-propagating spiral shocks. We also find that Ω _p depends strongly on inclination. Application of this technique will enable us to compare future EHT movies with the clockwise rotation of Sgr A* seen in near-infrared flares by GRAVITY. Pattern speed analysis of future EHT observations of M87* and Sgr A* may also provide novel constraints on black hole inclination and spin, as well as an independent measurement of black hole mass. |
| first_indexed | 2024-03-12T04:08:56Z |
| format | Article |
| id | doaj.art-6b4273aa4e44477884fa70062f9ba033 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T04:08:56Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-6b4273aa4e44477884fa70062f9ba0332023-09-03T11:09:49ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0195114610.3847/1538-4357/acd2c8Rotation in Event Horizon Telescope MoviesNicholas S. Conroy0https://orcid.org/0000-0003-2886-2377Michi Bauböck1https://orcid.org/0000-0002-5518-2812Vedant Dhruv2https://orcid.org/0000-0001-6765-877XDaeyoung Lee3https://orcid.org/0000-0002-3350-5588Avery E. Broderick4https://orcid.org/0000-0002-3351-760XChi-kwan Chan5https://orcid.org/0000-0001-6337-6126Boris Georgiev6https://orcid.org/0000-0002-3586-6424Abhishek V. Joshi7https://orcid.org/0000-0002-2514-5965Ben Prather8https://orcid.org/0000-0002-0393-7734Charles F. Gammie9https://orcid.org/0000-0001-7451-8935Department of Astronomy, University of Illinois at Urbana-Champaign , 1002 West Green Street, Urbana, IL 61801, USADepartment of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, IL 61801, USA; Illinois Center for the Advanced Study of the Universe, University of Illinois at Urbana-Champaign , 1110 West Green St., Urbana, IL 61801, USADepartment of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, IL 61801, USA; Illinois Center for the Advanced Study of the Universe, University of Illinois at Urbana-Champaign , 1110 West Green St., Urbana, IL 61801, USADepartment of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, IL 61801, USAPerimeter Institute for Theoretical Physics , 31 Caroline Street North, Waterloo, ON, N2L 2Y5, Canada; Department of Physics and Astronomy, University of Waterloo , 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada; Waterloo Centre for Astrophysics, University of Waterloo , Waterloo, ON, N2L 3G1, CanadaSteward Observatory and Department of Astronomy, University of Arizona , 933 N. Cherry Ave., Tucson, AZ 85721, USA; Data Science Institute, University of Arizona , 1230 N. Cherry Ave., Tucson, AZ 85721, USA; Program in Applied Mathematics, University of Arizona , 617 N. Santa Rita, Tucson, AZ 85721, USAPerimeter Institute for Theoretical Physics , 31 Caroline Street North, Waterloo, ON, N2L 2Y5, Canada; Department of Physics and Astronomy, University of Waterloo , 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada; Waterloo Centre for Astrophysics, University of Waterloo , Waterloo, ON, N2L 3G1, CanadaDepartment of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, IL 61801, USA; Illinois Center for the Advanced Study of the Universe, University of Illinois at Urbana-Champaign , 1110 West Green St., Urbana, IL 61801, USADepartment of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, IL 61801, USA; Los Alamos National Lab, Los Alamos, NM 87545, USADepartment of Astronomy, University of Illinois at Urbana-Champaign , 1002 West Green Street, Urbana, IL 61801, USA; Department of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, IL 61801, USA; Illinois Center for the Advanced Study of the Universe, University of Illinois at Urbana-Champaign , 1110 West Green St., Urbana, IL 61801, USA; NCSA, University of Illinois at Urbana-Champaign , 1205 W. Clark St., Urbana, IL 61801, USAThe Event Horizon Telescope (EHT) has produced images of M87* and Sagittarius A*, and will soon produce time sequences of images, or movies. In anticipation of this, we describe a technique to measure the rotation rate, or pattern speed Ω _p , from movies using an autocorrelation technique. We validate the technique on Gaussian random field models with a known rotation rate and apply it to a library of synthetic images of Sgr A* based on general relativistic magnetohydrodynamics simulations. We predict that EHT movies will have Ω _p ≈ 1° per GMc ^−3 , which is of order 15% of the Keplerian orbital frequency in the emitting region. We can plausibly attribute the slow rotation seen in our models to the pattern speed of inward-propagating spiral shocks. We also find that Ω _p depends strongly on inclination. Application of this technique will enable us to compare future EHT movies with the clockwise rotation of Sgr A* seen in near-infrared flares by GRAVITY. Pattern speed analysis of future EHT observations of M87* and Sgr A* may also provide novel constraints on black hole inclination and spin, as well as an independent measurement of black hole mass.https://doi.org/10.3847/1538-4357/acd2c8Black holesMagnetohydrodynamical simulations |
| spellingShingle | Nicholas S. Conroy Michi Bauböck Vedant Dhruv Daeyoung Lee Avery E. Broderick Chi-kwan Chan Boris Georgiev Abhishek V. Joshi Ben Prather Charles F. Gammie Rotation in Event Horizon Telescope Movies The Astrophysical Journal Black holes Magnetohydrodynamical simulations |
| title | Rotation in Event Horizon Telescope Movies |
| title_full | Rotation in Event Horizon Telescope Movies |
| title_fullStr | Rotation in Event Horizon Telescope Movies |
| title_full_unstemmed | Rotation in Event Horizon Telescope Movies |
| title_short | Rotation in Event Horizon Telescope Movies |
| title_sort | rotation in event horizon telescope movies |
| topic | Black holes Magnetohydrodynamical simulations |
| url | https://doi.org/10.3847/1538-4357/acd2c8 |
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