Revealing Hidden Substructures in the M_BH–σ Diagram, and Refining the Bend in the L–σ Relation

Abstract

Using 145 early-and late-type galaxies (ETGs and LTGs) with directly-measured super-massive black hole masses, M BH , we build upon our previous discoveries that: (i) LTGs, most of which have been alleged to contain a pseudobulge, follow the relation M BH ∝ M 2.16±0.32 * ,sph ; and (ii) the ETG relation M BH ∝ M 1.27±0.07 * ,sph is an artifact of ETGs with/without disks following parallel M BH ∝ M 1.9±0.2 * ,sph relations which are offset by an order of magnitude in the M BH -direction. Here, we searched for substructure in the M BH -(central velocity dispersion, σ) diagram using our recently published, multicomponent, galaxy decompositions; investigating divisions based on the presence of a depleted stellar core (major dry-merger), a disk (minor wet/dry-merger, gas accretion), or a bar (evolved unstable disk). The Sérsic and core-Sérsic galaxies define two distinct relations: M BH ∝ σ 5.75±0.34 and M BH ∝ σ 8.64±1.10 , with ∆ rms|BH = 0.55 and 0.46 dex, respectively. We also report on the consistency with the slopes and bends in the galaxy luminosity (L)-σ relation due to Sérsic and core-Sérsic ETGs, and LTGs which all have Sérsic light-profiles. Two distinct relations (superficially) reappear in the M BHσ diagram upon separating galaxies with/without a disk (primarily for the ETG sample), while we find no significant offset between barred and non-barred galaxies, nor between galaxies with/without active galactic nuclei. We also address selection biases purported to affect the scaling relations for dynamically-measured M BH samples. Our new, (morphological type)-dependent, M BH -σ relations more precisely estimate M BH in other galaxies, and hold implications for galaxy/black hole co-evolution theories, simulations, feedback, the pursuit of a black hole fundamental plane, and calibration of virial f -factors for reverberation-mapping.

A consistency test for determining whether ultracompact dwarf galaxies could be the remnant nuclei of threshed galaxies

“…-which is consistent with the symmetric M bh -σ relations inSahu et al (2019b) 3 -gives: log(M nc /M ) = (0.38 ± 0.06) log(M bh /[10 8.22 M ]) + (7.83 ± 0.20) = (0.38 ± 0.06) log(M bh /[10 7.89 M ]) + (7.70 ± 0.…”

“…However, our preferred use of the scaling relations involving the velocity dispersion may have circumvented this issue. This is because nucleated 5 early-and late-type Sérsic galaxies may follow the same M bhσ relation (Sahu et al 2019b). Whether they follow different M nc -σ relations is yet to be established.…”

WISDOM project – VII. Molecular gas measurement of the supermassive black hole mass in the elliptical galaxy NGC 7052

“…The M BH −σ e relation of Sahu et al (2019) predicts M BH = 1.0 +2.1 −0.7 × 10 9 M for NGC 7052 (assuming σ e = 266 ± 13 km s −1 , and including 0.44 dex of intrinsic scatter). Our result is in excellent agreement with this prediction, whereas the ionised-gas measurement of van der Marel & van den Bosch (1998) is significantly below it.…”

Re. I. Understanding galaxy sizes, associated luminosity densities, and the artificial division of the early-type galaxy population

“…Departures at low black hole masses, from the plane constructed by galaxies with high black hole masses, need not be a sign of different formation physics. This should be independent of the (R e -independent)-observation that the bulges of LTGs follow a different M bh -(bulge luminosity) relation than the bulges of ETGs Davis et al, 2018Davis et al, , 2019Sahu et al, 2019).…”

“…In addition, modern structural decompositions reveal multiple physical aj components in ETGs (e.g. Prieto et al, 2001;Läsker et al, 2014;Sahu et al, 2019). Nowadays, in such studies, Sérsic's model provides an accurate description of the spheroidal component of the galaxy.…”