The central black hole in the dwarf spheroidal galaxy Leo I Not supermassive, at most an intermediate-mass candidate

Abstract

It has been recently claimed that a surprisingly massive black hole (BH) is present in the core of the dwarf spheroidal galaxy (dSph) Leo I. Based on integral field spectroscopy, this finding challenges the typical expectation of dSphs hosting BHs of intermediate-mass, since such a BH would better be classified as supermassive. Indeed, the analysis points toward Leo I harboring a BH with a lower mass limit exceeding a few $10^6{M}_{\odot }$ at $1\sigma$, and the no BH case excluded at 95\% significance. Such a value, comparable to the entire stellar mass of the galaxy, makes Leo I a unique system that warrants further investigations. Using equilibrium models based on distribution functions (DFs) depending on actions $f(\mathbf{J})$ coupled with the same integral field spectroscopy data and an extensive exploration of a very large parameter space, we demonstrate, within a comprehensive Bayesian framework of model-data comparison, that the posterior on the BH mass is flat towards the low-mass end and, thus, that the kinematics of the central galaxy region only imposes an upper limit on the BH mass of few $10^5{M}_{\odot }$ (at $3\sigma$). Such an upper limit brings back the putative BH of Leo I under the category of intermediate-mass BHs, and it is also in line with formation scenarios and expectations from scaling relations at the mass regime of dwarf galaxies.

arXiv commentAccepted for publication in A&A Letters

References in corpus (30)

• emcee: The MCMC Hammer
• The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III
• The observed properties of dwarf galaxies in and around the Local Group
• GW190521: A Binary Black Hole Merger with a Total Mass of $150M_{\odot }$
• An 800-million-solar-mass black hole in a significantly neutral Universe at redshift 7.5
• Intermediate-Mass Black Holes
• AGAMA: Action-based galaxy modelling architecture
• An Intermediate-Mass Black Hole in the Globular Cluster G1: Improved Significance from New Keck and Hubble Space Telescope Observations
• MOCCA Code for Star Cluster Simulations - IV. A new Scenario for Intermediate Mass Black Hole Formation in Globular Clusters
• New Limits on an Intermediate Mass Black Hole in Omega Centauri: II. Dynamical Models
• Dark Matter Cores and Cusps: The Case of Multiple Stellar Populations in Dwarf Spheroidals
• The Velocity Dispersion Profile of the Remote Dwarf Spheroidal Galaxy Leo I: A Tidal Hit and Run?
• A MegaCam Survey of Outer Halo Satellites. III. Photometric and Structural Parameters
• Deviations from the Local Hubble Flow. I. The Tip of the Red Giant Branch as a Distance Indicator
• The Space Motion of Leo I: Hubble Space Telescope Proper Motion and Implied Orbit
• Proper Motions, Orbits, and Tidal Influences of Milky Way Dwarf Spheroidal Galaxies
• The velocity dispersion profile of NGC 6388 from resolved-star spectroscopy: no evidence of a central cusp and new constraints on the black hole mass
• No Evidence for Intermediate-Mass Black Holes in Globular Clusters: Strong Constraints from the JVLA
• Kinematic signature of an intermediate-mass black hole in the globular cluster NGC 6388
• RUN DMC: An efficient, parallel code for analyzing Radial Velocity Observations using N-body Integrations and Differential Evolution Markov chain Monte Carlo
• Action-based distribution functions for spheroidal galaxy components
• The distance to the Leo I dwarf spheroidal galaxy from the Red Giant Branch Tip
• A centrally heated dark halo for our Galaxy
• Self-consistent models of our Galaxy
• Action-based dynamical models of dwarf spheroidal galaxies: application to Fornax
• Upper Limits on Central Black Hole Masses of Globular Clusters from Radio Emission and a Possible Black Hole Detection in the Ursa Minor Dwarf Galaxy
• Dynamical analysis of the dark matter and central black hole mass in the dwarf spheroidal Leo I
• Action-based models for dwarf spheroidal galaxies and globular clusters
• Prospects for detection of intermediate-mass black holes in globular clusters using integrated-light spectroscopy
• Extreme Tidal Stripping May Explain the Overmassive Black Hole in Leo I: a Proof of Concept

Cited by in corpus (5)

• EDGE: Dark matter core creation depends on the timing of star formation
• Leo I: the classical dwarf spheroidal galaxy with the highest dark-matter density
• The tidal features of the classical Milky Way satellites: Expected in MOND but inconsistent with cold dark matter models
• Multi-component, axisymmetric dynamical models of dSphs based on distribution functions: inferences on dark matter and intermediate-mass black holes in Draco and Ursa Minor
• Distribution functions for spheroids