More Like this

1. The Scatter Matters: Circumgalactic Metal Content in the Context of the M–σ Relation

   https://doi.org/10.3847/1538-4357/ad39eb  

   Sanchez, N Nicole; Werk, Jessica K; Christensen, Charlotte; Telford, O Grace; Quinn, Thomas R; Tremmel, Michael; Mead, Jennifer; Sharma, Ray S; Brooks, Alyson M (May 2024, The Astrophysical Journal)

   Abstract The interaction between supermassive black hole (SMBH) feedback and the circumgalactic medium (CGM) continues to be an open question in galaxy evolution. In our study, we use smoothed particle hydrodynamics simulations to explore the impact of SMBH feedback on galactic metal retention and the motion of metals and gas into and through the CGM of L_*galaxies. We examine 140 galaxies from the 25 Mpc cosmological volume Romulus25, with stellar masses between log(M_*/M_⊙) = 9.5–11.5. We measure the fraction of metals remaining in the interstellar medium (ISM) and CGM of each galaxy and calculate the expected mass of each SMBH based on theM_BH–σrelation (Kormendy & Ho 2013). The deviation of each SMBH from its expected mass, ΔM_BH, is compared to the potential of its host viaσ. We find that SMBHs with accreted mass aboveM_BH–σare more effective at removing metals from the ISM than undermassive SMBHs in star-forming galaxies. Overall, overmassive SMBHs suppress the total star formation of their host galaxies and more effectively move metals from the ISM into the CGM. However, we see little to no evacuation of gas from the CGM out of their halos, in contrast with other simulations. Finally, we predict that Civcolumn densities in the CGM of L_*galaxies are unlikely to depend on host galaxy SMBH mass. Our results show that the scatter in the low-mass end of the M_BH–σrelation may indicate how effective an SMBH is in the local redistribution of mass in its host galaxy. 

   more » « less
2. Regulation of Star Formation by a Hot Circumgalactic Medium

   https://doi.org/10.3847/1538-4357/acc4c7  

   Carr, Christopher; Bryan, Greg L.; Fielding, Drummond B.; Pandya, Viraj; Somerville, Rachel S. (May 2023, The Astrophysical Journal)

   Abstract Galactic outflows driven by supernovae (SNe) are thought to be a powerful regulator of a galaxy’s star-forming efficiency. Mass, energy, and metal outflows ( η M , η E , and η Z , here normalized by the star formation rate, the SNe energy, and metal production rates, respectively) shape galaxy properties by both ejecting gas and metals out of the galaxy and by heating the circumgalactic medium (CGM), preventing future accretion. Traditionally, models have assumed that galaxies self-regulate by ejecting a large fraction of the gas, which enters the interstellar medium (ISM), although whether such high mass loadings agree with observations is still unclear. To better understand how the relative importance of ejective (i.e., high mass loading) versus preventative (i.e., high energy loading) feedback affects the present-day properties of galaxies, we develop a simple gas-regulator model of galaxy evolution, where the stellar mass, ISM, and CGM are modeled as distinct reservoirs which exchange mass, metals, and energy at different rates within a growing halo. Focusing on the halo mass range from 10 10 to 10 12 M ⊙ , we demonstrate that, with reasonable parameter choices, we can reproduce the stellar-to-halo mass relation and the ISM-to-stellar mass relation with low-mass-loaded ( η M ∼ 0.1–10) but high-energy-loaded ( η E ∼ 0.1–1) winds, with self-regulation occurring primarily through heating and cooling of the CGM. We show that the model predictions are robust against changes to the mass loading of outflows but are quite sensitive to our choice of the energy loading, preferring η E ∼ 1 for the lowest-mass halos and ∼0.1 for Milky Way–like halos. 

   more » « less
3. Ejective and preventative: the IllustrisTNG black hole feedback and its effects on the thermodynamics of the gas within and around galaxies

   https://doi.org/10.1093/mnras/staa2607  

   Zinger, Elad; Pillepich, Annalisa; Nelson, Dylan; Weinberger, Rainer; Pakmor, Rüdiger; Springel, Volker; Hernquist, Lars; Marinacci, Federico; Vogelsberger, Mark (October 2020, Monthly Notices of the Royal Astronomical Society)

   null (Ed.)

   ABSTRACT Supermassive black holes (SMBHs) that reside at the centres of galaxies can inject vast amounts of energy into the surrounding gas and are thought to be a viable mechanism to quench star formation in massive galaxies. Here, we study the $$10^{9-12.5}\, \mathrm{M_\odot }$$ stellar mass central galaxy population of the IllustrisTNG simulation, specifically the TNG100 and TNG300 volumes at z = 0, and show how the three components – SMBH, galaxy, and circumgalactic medium (CGM) – are interconnected in their evolution. We find that gas entropy is a sensitive diagnostic of feedback injection. In particular, we demonstrate how the onset of the low-accretion black hole (BH) feedback mode, realized in the IllustrisTNG model as a kinetic, BH-driven wind, leads not only to star formation quenching at stellar masses $$\gtrsim 10^{10.5}\, \mathrm{M_\odot }$$ but also to a change in thermodynamic properties of the (non-star-forming) gas, both within the galaxy and beyond. The IllustrisTNG kinetic feedback from SMBHs increases the average gas entropy, within the galaxy and in the CGM, lengthening typical gas cooling times from $$10\!-\!100\, \mathrm{Myr}$$ to $$1\!-\!10\, \mathrm{Gyr}$$, effectively ceasing ongoing star formation and inhibiting radiative cooling and future gas accretion. In practice, the same active galactic nucleus (AGN) feedback channel is simultaneously ‘ejective’ and ‘preventative’ and leaves an imprint on the temperature, density, entropy, and cooling times also in the outer reaches of the gas halo, up to distances of several hundred kiloparsecs. In the IllustrisTNG model, a long-lasting quenching state can occur for a heterogeneous CGM, whereby the hot and dilute CGM gas of quiescent galaxies contains regions of low-entropy gas with short cooling times. 

   more » « less
4. Running late: testing delayed supermassive black hole growth models against the quasar luminosity function

   https://doi.org/10.1093/mnras/stac398  

   Tillman, Megan Taylor; Wellons, Sarah; Faucher-Giguère, Claude-André; Kelley, Luke Zoltan; Anglés-Alcázar, Daniel (March 2022, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT Observations of massive galaxies at low redshift have revealed approximately linear scaling relations between the mass of a supermassive black hole (SMBH) and properties of its host galaxy. How these scaling relations evolve with redshift and whether they extend to lower-mass galaxies, however, remain open questions. Recent galaxy formation simulations predict a delayed, or ‘two-phase,’ growth of SMBHs: slow, highly intermittent BH growth due to repeated gas ejection by stellar feedback in low-mass galaxies, followed by more sustained gas accretion that eventually brings BHs on to the local scaling relations. The predicted two-phase growth implies a steep increase, or ‘kink,’ in BH-galaxy scaling relations at a stellar mass $$\rm {M}_{*}\sim 5\times 10^{10}$$ M⊙. We develop a parametric, semi-analytic model to compare different SMBH growth models against observations of the quasar luminosity function (QLF) at z ∼ 0.5−4. We compare models in which the relation between SMBH mass and galaxy mass is purely linear versus two-phase models. The models are anchored to the observed galaxy stellar mass function, and the BH mass functions at different redshifts are consistently connected by the accretion rates contributing to the QLF. The best fits suggest that two-phase evolution is significantly preferred by the QLF data over a purely linear scaling relation. Moreover, when the model parameters are left free, the two-phase model fits imply a transition mass consistent with that predicted by simulations. Our analysis motivates further observational tests, including measurements of BH masses and active galactic nuclei activity at the low-mass end, which could more directly test two-phase SMBH growth. 

   more » « less
5. The Impact of Applying Black Hole–Host Galaxy Scaling Relations to Large Galaxy Populations

   https://doi.org/10.3847/1538-4357/ade30a  

   Huber, Maggie C; Simon, Joseph; Comerford, Julia M (July 2025, The Astrophysical Journal)

   Abstract Supermassive black holes (SMBHs) with dynamically measured masses have shown empirical correlations with host galaxy properties. These correlations are often the only method available to estimate SMBH masses and gather statistics for large galaxy populations across a range of redshifts, even though the scaling relations themselves are derived from a small subset of nearby galaxies. Depending on the scaling relation used, estimated SMBH masses can vary significantly. The most widely used scaling relations are theM_BH–M_bulgeandM_BH–σrelations, whereM_bulgeis galaxy bulge mass andσis the bulge velocity dispersion. In this paper, we determine how severely the choice of scaling relation impacts SMBH mass estimates for different subsets of a large galaxy population. For this analysis, we use a sample of ∼400,000 galaxies, including 1240 Type 1 active galactic nuclei from the Sloan Digital Sky Survey. We calculate SMBH masses fromM_BH–M_bulgeandM_BH–σand compare to single-epoch virial SMBH masses from broad-line Hβ, which are derived independently of black hole–host galaxy scaling relations. We find that SMBH masses derived from the single-epoch virial relation for Hβare better reproduced byM_BH–σthanM_BH–M_bulge. Finally, in cases whereσandM_bulgecannot be measured directly, we show that it is possible to inferσfrom photometry with more accuracy than we can inferM_bulge. 

   more » « less