Selection bias in dynamically measured supermassive black hole samples: scaling relations and correlations between residuals in semi-analytic galaxy formation models

Abstract

Recent work has confirmed that the scaling relations between the masses of supermassive black holes and host-galaxy properties such as stellar masses and velocity dispersions may be biased high. Much of this may be caused by the requirement that the black-hole sphere of influence must be resolved for the black-hole mass to be reliably estimated. We revisit this issue with a comprehensive galaxy evolution semi-analytic model. Once tuned to reproduce the (mean) correlation of black-hole mass with velocity dispersion, the model cannot account for the correlation with stellar mass. This is independent of the model's parameters, thus suggesting an internal inconsistency in the data. The predicted distributions, especially at the low-mass end, are also much broader than observed. However, if selection effects are included, the model's predictions tend to align with the observations. We also demonstrate that the correlations between the residuals of the scaling relations are more effective than the relations themselves at constraining AGN feedback models. In fact, we find that our model, while in apparent broad agreement with the scaling relations when accounting for selection biases, yields very weak correlations between their residuals at fixed stellar mass, in stark contrast with observations. This problem persists when changing the AGN feedback strength, and is also present in the hydrodynamic cosmological simulation Horizon-AGN, which includes state-of-the-art treatments of AGN feedback. This suggests that current AGN feedback models are too weak or simply not capturing the effect of the black hole on the stellar velocity dispersion.

Detection of faint broad emission lines in type 2 AGNs – III. On the MBH-σ⋆ relation of type 2 AGNs

“…As discussed in Reines & Volonteri (2015), there is the possibility that if BH seeds are massive (e.g. M BH = 10 5 M ⊙ ) the low-mass end of the relation between BHs and galaxies flattens toward an asymptotic value, creating a characteristic "plume" of less grown BHs (see also Barausse et al 2017). …”

Testing modified gravity at cosmological distances with LISA standard sirens

“…The baryonic structures that are evolved include a chemically pristine diffuse inter-galactic medium, which is either shock heated to the virial temperature of Dark Matter halos, or flows into the halos along cold filaments [179]; a cold, chemically enriched inter-stellar medium (in both a disk and bulge component); stellar disks and bulges, forming from the inter-stellar medium (with supernova feedback included in the star formation description); nuclear star clusters, forming from in situ star formation and from the migration of globular clusters to the nuclear region [172,180]; and massive black holes, accreting from nuclear gas reservoirs (which, in turn, form after major galactic mergers or galactic disk instabilities, which trigger bursts of star formation in the bulge and inflows of gas to the nuclear region). The black holes affect the overall evolution via the feedback of their active galactic nucleus (AGN) phases, which ensures also that the observed local correlations between the properties of massive black holes and those of their galactic hosts are correctly reproduced [170,171,181].…”

Black hole – Galaxy correlations in simba

“…Nonetheless, for bulge-dominated galaxies the predicted M BH − σ relation in Simba nicely tracks observations. This agreement may be surprising because Shankar et al (2016) argued that, owing to biases in the measurements of black hole masses, the observed M BH −M relation and the M BH −σ relation are inconsistent with each other, so it is surprising that Simba can match both simultaneously, which other models have had some difficulty doing (Barausse et al 2017). A relevant aspect of Simba is that at a given M , large black holes live in higher-σ galaxies, as shown by the colour-coding in Figure 2.…”