A Supermassive Black Hole in a Diminutive Ultracompact Dwarf Galaxy Discovered with JWST/NIRSpec+IFU

Abstract The integral-field unit mode of the Near-Infrared Spectrograph (NIRSpec+IFU) mounted on the James Webb Space Telescope has now enabled kinematic studies of smaller and less massive compact stellar systems in which to search for central massive black holes (BHs) than ever before. We present here the first such detection using NIRSpec+IFU in its highest resolution ( R ∼ 2700) mode. We report the detection of a central BH with mass <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi class="MJX-tex-calligraphic" mathvariant="script">M</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">BH</mml:mi> </mml:mrow> </mml:msub> </mml:math> = 2.1 ± 1.1 × 10 6 M ⊙ (1 σ uncertainties) in UCD736 orbiting within the Virgo galaxy cluster. Schwarzschild modeling of the 1D kinematic profile rules out a zero-mass central BH at the 3 σ level; however, two other independent modeling approaches fail to rule out a zero-mass BH at &gt;1 σ significance. The presence of such a massive BH strongly argues against a globular cluster origin of this ultracompact dwarf galaxy (UCD), and rather suggests a tidally stripped formation route from a former ≳10 9 M ⊙ dwarf galaxy host. This represents the detection of a BH in the most compact ( r h ≈ 15 pc) stellar system to date, with a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi class="MJX-tex-calligraphic" mathvariant="script">M</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">BH</mml:mi> </mml:mrow> </mml:msub> </mml:math> corresponding to ∼8% of the system’s stellar mass, roughly in line with previously reported UCD BH detections and comparable to the BH detected in the compact elliptical galaxy NGC4486B.

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Publication Details

Journal
The Astrophysical Journal Letters
Published
2025-09-18
DOI
https://doi.org/10.3847/2041-8213/ae028e
Citations
4
Primary Topic
Galaxies: Formation, Evolution, Phenomena
Type
article
Field-Weighted Citation Impact
4.62

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article

A Supermassive Black Hole in a Diminutive Ultracompact Dwarf Galaxy Discovered with JWST/NIRSpec+IFU

John P. Blakeslee, Laura Ferrarese, Chengze Liu, Misty C. Bentz et al.
4 citations
The Astrophysical Journal Letters
Galaxies: Formation, Evolution, Phenomena
4.62
article

A Supermassive Black Hole in a Diminutive Ultracompact Dwarf Galaxy Discovered with JWST/NIRSpec+IFU

John P. Blakeslee, Laura Ferrarese, Chengze Liu, Misty C. Bentz, Matthew A. Taylor, Vivienne Baldassare, Kaixiang Wang, Eugene Vasiliev, Patrick Côté, Solveig Thompson, Tyrone E. Woods, Joel Roediger, Youkyung Ko, Holger Baumgardt, Kristen C. Dage, Behzad Tahmasebzadeh, Monica Valluri, M. J. Drinkwater, Eric W. Peng, Zach Sumners, Drew Lapeer
article en
4 citations

Abstract

Abstract The integral-field unit mode of the Near-Infrared Spectrograph (NIRSpec+IFU) mounted on the James Webb Space Telescope has now enabled kinematic studies of smaller and less massive compact stellar systems in which to search for central massive black holes (BHs) than ever before. We present here the first such detection using NIRSpec+IFU in its highest resolution ( R ∼ 2700) mode. We report the detection of a central BH with mass <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi class="MJX-tex-calligraphic" mathvariant="script">M</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">BH</mml:mi> </mml:mrow> </mml:msub> </mml:math> = 2.1 ± 1.1 × 10 6 M ⊙ (1 σ uncertainties) in UCD736 orbiting within the Virgo galaxy cluster. Schwarzschild modeling of the 1D kinematic profile rules out a zero-mass central BH at the 3 σ level; however, two other independent modeling approaches fail to rule out a zero-mass BH at &gt;1 σ significance. The presence of such a massive BH strongly argues against a globular cluster origin of this ultracompact dwarf galaxy (UCD), and rather suggests a tidally stripped formation route from a former ≳10 9 M ⊙ dwarf galaxy host. This represents the detection of a BH in the most compact ( r h ≈ 15 pc) stellar system to date, with a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi class="MJX-tex-calligraphic" mathvariant="script">M</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">BH</mml:mi> </mml:mrow> </mml:msub> </mml:math> corresponding to ∼8% of the system’s stellar mass, roughly in line with previously reported UCD BH detections and comparable to the BH detected in the compact elliptical galaxy NGC4486B.

The Astrophysical Journal LettersVol. 991(1)
Herzberg Institute of Astrophysics (CA), The University of Queensland (AU), University of Calgary (CA), Georgia State University (US), Shanghai Jiao Tong University (CN), Peking University (CN), Curtin University (AU), University of Cambridge (GB), University of Massachusetts Amherst (US), University of Michigan (US), Korea Astronomy and Space Science Institute (KR), University of Surrey (GB), Kavli Institute for Theoretical Sciences (CN), Community Science and Data Center (US), NSF NOIRLab (US), International Centre for Radio Astronomy Research (AU), University of Manitoba (CA), McGill University (CA), Washington State University (US)
National Science Foundation, National Aeronautics and Space Administration, Space Telescope Science Institute, National Natural Science Foundation of China, Science and Technology Facilities Council
Openalex Percentile: Top 5%
Galaxies: Formation, Evolution, Phenomena
4.62
DOIOpen Access PDFOpenAlex
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