We present radial profiles of luminosity-weighted age (age
Quenching of star formation in the central galaxies of cosmological halos is thought to result from energy released as gas accretes onto a supermassive black hole. The same energy source also appears to lower the central density and raise the cooling time of baryonic atmospheres in massive halos, thereby limiting both star formation and black hole growth, by lifting the baryons in those halos to greater altitudes. One predicted signature of that feedback mechanism is a nearly linear relationship between the central black hole’s mass (
- Award ID(s):
- 2106575
- PAR ID:
- 10480746
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 960
- Issue:
- 1
- ISSN:
- 0004-637X
- Format(s):
- Medium: X Size: Article No. 28
- Size(s):
- Article No. 28
- Sponsoring Org:
- National Science Foundation
More Like this
-
Abstract L ) and ΔΣSFRfor various populations of high- and low-mass central and satellite galaxies in the TNG100 cosmological simulation. Using these profiles, we investigate the impact of intrinsic and environmental factors on the radial distribution of star formation. For both central galaxies and satellites, we investigate the effects of black hole mass, cumulative active galactic nucleus (AGN) feedback energy, morphology, halo mass, and local galaxy overdensity on the profiles. In addition, we investigate the dependence of radial profiles of the satellite galaxies as a function of the redshifts at which they joined their hosts, as well as the net change in star-forming gas mass since the satellites joined their host. We find that high-mass (M *> 1010.5M ⊙) central and satellite galaxies show evidence of inside-out quenching driven by AGN feedback. Effects from environmental processes only become apparent in averaged profiles at extreme halo masses and local overdensities. We find that the dominant quenching process for low-mass galaxies (M *< 1010M ⊙) is environmental, generally occurring at low halo mass and high local galaxy overdensity for low-mass central galaxies and at high host halo masses for low-mass satellite galaxies. Overall, we find that environmental processes generally drive quenching from the outside-in. -
Abstract Semianalytic models (SAMs) systematically predict higher-stellar mass scatter at a given halo mass than hydrodynamical simulations and most empirical models. Our goal is to investigate the physical origin of this scatter by exploring modifications to the physics in the SAM
Dark Sage . We design two black hole formation models that approximate results from theIllustrisTNG 300-1 hydrodynamical simulation. In the first model, we assign a fixed black hole mass of 106M ⊙to every halo that reaches 1010.5M ⊙. In the second model, we disregard any black hole growth as implemented in the standardDark Sage model. Instead, we force all black hole masses to follow the medianz = 0 black hole mass–halo mass relation inIllustrisTNG 300-1 with an imposed fixed scatter. We find that each model on its own does not significantly reduce the scatter in stellar mass. To explore the effects of active galactic nucleus (AGN) feedback in addition to black hole seeding, we replace the native Dark Sage AGN feedback model with a simple model where we turn off cooling for galaxies with black hole masses above 108M ⊙. With the additional modification in AGN feedback, we find that the supermassive black hole seeding and fixed conditional distribution models create a significant reduction in the scatter in stellar mass at halo masses between 1011–14M ⊙. These results suggest that AGN feedback in SAMs acts in a qualitatively different way than feedback implemented in cosmological simulations. Either or both may require substantial modification to match the empirically inferred scatter in the stellar mass–halo mass relation. -
Abstract The scaling of galaxy properties with halo mass suggests that feedback loops regulate star formation, but there is no consensus yet about how those feedback loops work. To help clarify discussions of galaxy-scale feedback, Paper I presented a very simple model for supernova feedback that it called the minimalist regulator model. This follow-up paper interprets that model and discusses its implications. The model itself is an accounting system that tracks all of the mass and energy associated with a halo’s circumgalactic baryons—the central galaxy’s atmosphere. Algebraic solutions for the equilibrium states of that model reveal that star formation in low-mass halos self-regulates primarily by expanding the atmospheres of those halos, ultimately resulting in stellar masses that are insensitive to the mass-loading properties of galactic winds. What matters most is the proportion of supernova energy that couples with circumgalactic gas. However, supernova feedback alone fails to expand galactic atmospheres in higher-mass halos. According to the minimalist regulator model, an atmospheric contraction crisis ensues, which may be what triggers strong black hole feedback. The model also predicts that circumgalactic medium properties emerging from cosmological simulations should depend largely on the specific energy of the outflows they produce, and we interpret the qualitative properties of several numerical simulations in light of that prediction.
-
Abstract We present measurements of black hole masses and Eddington ratios (
λ Edd) for a sample of 38 bright (M 1450< −24.4 mag) quasars at 5.8 ≲z ≲ 7.5, derived from Very Large Telescope/X–shooter near–IR spectroscopy of their broad Civ and Mgii emission lines. The black hole masses (on average,M BH∼ 4.6 × 109M ⊙) and accretion rates (0.1 ≲λ Edd≲ 1.0) are broadly consistent with that of similarly luminous 0.3 ≲z ≲ 2.3 quasars, but there is evidence for a mild increase in the Eddington ratio abovez ≳ 6. Combined with deep Atacama Large Millimeter/submillimeter Array (ALMA) observations of the [CII ] 158μ m line from the host galaxies and VLT/MUSE investigations of the extended Lyα halos, this study provides fundamental clues to models of the formation and growth of the first massive galaxies and black holes. Compared to local scaling relations,z ≳ 5.7 black holes appear to be over-massive relative to their hosts, with accretion properties that do not change with host galaxy morphologies. Assuming that the kinematics of theT ∼ 104K gas, traced by the extended Lyα halos, are dominated by the gravitational potential of the dark matter halo, we observe a similar relation between black hole mass and circular velocity as reported forz ∼ 0 galaxies. These results paint a picture where the first supermassive black holes reside in massive halos atz ≳ 6 and lead the first stages of galaxy formation by rapidly growing in mass with a duty cycle of order unity. The duty cycle needs to drastically drop toward lower redshifts, while the host galaxies continue forming stars at a rate of hundreds of solar masses per year, sustained by the large reservoirs of cool gas surrounding them. -
Abstract We have simulated the collapse and evolution of the core of a solar-metallicity 40
M ⊙star and find that it explodes vigorously by the neutrino mechanism, despite its very high “compactness.” Within ∼1.5 s of explosion, a black hole forms. The explosion is very asymmetrical and has a total explosion energy of ∼1.6 × 1051erg. At black hole formation, its baryon mass is ∼2.434M ⊙and gravitational mass is 2.286M ⊙. Seven seconds after black hole formation, an additional ∼0.2M ⊙is accreted, leaving a black hole baryon mass of ∼2.63M ⊙. A disk forms around the proto−neutron star, from which a pair of neutrino-driven jets emanates. These jets accelerate some of the matter up to speeds of ∼45,000 km s−1and contain matter with entropies of ∼50. The large spatial asymmetry in the explosion results in a residual black hole recoil speed of ∼1000 km s−1. This novel black hole formation channel now joins the other black hole formation channel between ∼12 and ∼15M ⊙discovered previously and implies that the black hole/neutron star birth ratio for solar-metallicity stars could be ∼20%. However, one channel leaves black holes in perhaps the ∼5–15M ⊙range with low kick speeds, while the other leaves black holes in perhaps the ∼2.5–3.0M ⊙mass range with high kick speeds. However, even ∼8.8 s after core bounce the newly formed black hole is still accreting at a rate of ∼2 × 10−2M ⊙s−1, and whether the black hole eventually achieves a significantly larger mass over time is yet to be determined.