A Search for Wandering Black Holes in the Milky Way with Gaia and DECaLS

Greene, Jenny E.; Lancaster, Lachlan; Ting, Yuan-Sen; Koposov, S. E.; Danieli, Shany; Huang, Song; Jiang, Fangzhou; Greco, Johnny P.; Strader, Jay

doi:10.3847/1538-4357/ac0896

Cited by 21 publications

(17 citation statements)

References 102 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another complicating factor in MBH detection is distance from the galaxy center. Both simulations (Bellovary et al 2019(Bellovary et al , 2021 and observations (Mezcua & Domínguez Sánchez 2020;Reines et al 2020;Greene et al 2021) have Figure 4. Active fractions vs. stellar mass for the typical two-mode accretion model (solid thick); for a single-mode accretion model with a flat radiative efficiency ò r = 0.1 (solid thin); for two-mode accretion with a flat X-ray bolometric correction, k bol,X = 25 (dotted); and for two-mode accretion with a luminosity-dependent bolometric correction derived from X-ray-selected AGN (Lusso et al 2012;dashed).…”

Section: Population Of Hidden Mbhsmentioning

confidence: 84%

A Hidden Population of Massive Black Holes in Simulated Dwarf Galaxies

Sharma

Brooks

Tremmel

et al. 2022

ApJ

View full text Add to dashboard Cite

We explore the characteristics of actively accreting massive black holes (MBHs) within dwarf galaxies in the Romulus25 cosmological hydrodynamic simulation. We examine the MBH occupation fraction, X-ray active fractions, and active galactic nucleus (AGN) scaling relations within dwarf galaxies of stellar mass 108 M ⊙ < M star < 1010 M ⊙ out to redshift z = 2. In the local universe, the MBH occupation fraction is consistent with observed constraints, dropping below unity at M star < 3 × 1010 M ⊙, M 200 < 3 × 1011 M ⊙. Local dwarf AGN in Romulus25 follow observed scaling relations between AGN X-ray luminosity, stellar mass, and star formation rate, though they exhibit slightly higher active fractions and number densities than comparable X-ray observations. Since z = 2, the MBH occupation fraction has decreased, the population of dwarf AGN has become overall less luminous, and as a result the overall number density of dwarf AGN has diminished. We predict the existence of a large population of MBHs in the local universe with low X-ray luminosities and high contamination from X-ray binaries and the hot interstellar medium that are undetectable by current X-ray surveys. These hidden MBHs make up 76% of all MBHs in local dwarf galaxies and include many MBHs that are undermassive relative to their host galaxy’s stellar mass. Their detection relies on not only greater instrument sensitivity but also better modeling of X-ray contaminants or multiwavelength surveys. Our results indicate that dwarf AGN were substantially more active in the past, despite having low luminosity today, and that future deep X-ray surveys may uncover many hidden MBHs in dwarf galaxies out to at least z = 2.

show abstract

Section: Population Of Hidden Mbhsmentioning

confidence: 84%

A Hidden Population of Massive Black Holes in Simulated Dwarf Galaxies

Sharma

Brooks

Tremmel

et al. 2022

ApJ

View full text Add to dashboard Cite

show abstract

“…Another complicating factor in MBH detection is distance from the galaxy center. Both simulations (Bellovary et al 2019(Bellovary et al , 2021 and observations (Reines et al 2020;Mezcua & Domínguez Sánchez 2020;Greene et al 2021) have found MBHs at large radii from the centers of dwarf galaxies. Galaxies in Romulus25 have also been found to frequently host off-center MBHs at radii > 2 kpc from the halo center (Ricarte et al 2021a,b).…”

Section: Population Of Hidden Mbhsmentioning

confidence: 90%

A hidden population of massive black holes in simulated dwarf galaxies

Sharma¹,

Brooks²,

Tremmel³

et al. 2022

Preprint

View full text Add to dashboard Cite

We explore the characteristics of actively accreting MBHs within dwarf galaxies in the Romulus25 cosmological hydrodynamic simulation. We examine the MBH occupation fraction, x-ray active fractions, and AGN scaling relations within dwarf galaxies of stellar mass 10 8 < M star < 10 10 M out to redshift z = 2. In the local universe, the MBH occupation fraction is consistent with observed constraints, dropping below unity at M star < 3 × 10 10 M , M 200 < 3 × 10 11 M . Local dwarf AGN in Romulus25 follow observed scaling relations between AGN x-ray luminosity, stellar mass, and star formation rate, though they exhibit slightly higher active fractions and number densities than comparable x-ray observations. Since z = 2, the MBH occupation fraction has decreased, the population of dwarf AGN has become overall less luminous, and as a result, the overall number density of dwarf AGN has diminished. We predict the existence of a large population of MBHs in the local universe with low x-ray luminosities and high contamination from x-ray binaries and the hot interstellar medium that are undetectable by current x-ray surveys. These hidden MBHs make up 76% of all MBHs in local dwarf galaxies, and include many MBHs that are undermassive relative to their host galaxy's stellar mass. Their detection relies not only on greater instrument sensitivity but on better modeling of x-ray contaminants or multi-wavelength surveys. Our results indicate dwarf AGN were substantially more active in the past despite being low-luminosity today, and indicate future deep x-ray surveys may uncover many hidden MBHs in dwarf galaxies out to at least z = 2.

show abstract

“…The presence of a wandering IMBH in the MW galaxy would cause several effects, some of which may be detectable. First, a stellar density cusp, with typical radial density profile 𝜌 ∝ 𝑟 −7/4 , is expected to form around massive black holes (Bahcall & Wolf 1976;Greene et al 2021). Although this enhanced stellar density is generally challenging to detect directly, it can bear consequences which are observable, e.g., a different spatial distributions of neutron stars compared to a model without an IMBH (Kızıltan et al 2017).…”

Section: Discussionmentioning

confidence: 99%

“…Recent studies (e.g., Bellovary et al 2010;González & Guzmán 2018;Greene et al 2021;Ricarte et al 2021b,a) suggest that IMBHs may be wandering in the MW. These objects could have originated via several mechanisms, also in a dwarf that is subsequently captured by the MW.…”

mentioning

confidence: 98%

Detectability of Wandering Intermediate-Mass Black Holes in the Milky Way Galaxy from Radio to X-rays

Seepaul¹,

Pacucci²,

Narayan³

2022

Preprint

View full text Add to dashboard Cite

Intermediate-mass black holes (IMBHs, 10 3−6 M ), are typically found at the center of dwarf galaxies and might be wandering, thus far undetected, in the Milky Way (MW). We use model spectra for advection-dominated accretion flows to compute the typical fluxes, in a range of frequencies spanning from radio to X-rays, emitted by a putative population of 10 5 M IMBHs wandering in five realistic, volume-weighted, MW environments. We predict that ∼ 27% of the wandering IMBHs can be detected in the X-ray with Chandra, ∼ 37% in the near-infrared with the Roman Space Telescope, ∼ 49% in the sub-mm with CMB-S4 and ∼ 57% in the radio with ngVLA. We find that the brightest fluxes are emitted by IMBHs passing through molecular clouds or cold neutral medium, where they are always detectable. We propose criteria to facilitate the selection of candidates in multi-wavelength surveys. Specifically, we compute the X-ray to optical ratio (𝛼 ox ) and the optical to sub-mm ratio, as a function of the accretion rate of the IMBH. We show that at low rates the sub-mm emission of IMBHs is significantly higher than the optical, UV and X-ray emission. Finally, we place upper limits on the number 𝑁 • of these objects in the MW: 𝑁 • < 2000 and 𝑁 • < 100, based on our detectability expectations and current lack of detections in molecular clouds and cold neutral medium, respectively. These predictions will guide future searches of IMBHs in the MW, which will be instrumental to understanding their demographics and evolution.

show abstract

A Search for Wandering Black Holes in the Milky Way with Gaia and DECaLS

Cited by 21 publications

References 102 publications

A Hidden Population of Massive Black Holes in Simulated Dwarf Galaxies

A Hidden Population of Massive Black Holes in Simulated Dwarf Galaxies

A hidden population of massive black holes in simulated dwarf galaxies

Detectability of Wandering Intermediate-Mass Black Holes in the Milky Way Galaxy from Radio to X-rays

Contact Info

Product

Resources

About