Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 1308.3719

Consequences of Mechanical and Radiative Feedback from Black Holes in Disc Galaxy Mergers

Ena Choi·Thorsten Naab·Jeremiah P. Ostriker·Peter H. Johansson·Benjamin P. Moster
View original source ↗Read source document ↗Export metadata ↓

Abstract

We study the effect of AGN mechanical and radiation feedback on the formation of bulge dominated galaxies via mergers of disc galaxies. The merging galaxies have mass-ratios of 1:1 to 6:1 and include pre-existing hot gaseous halos to properly account for the global impact of AGN feedback. Using smoothed particle hydrodynamics simulation code (GADGET-3) we compare three models with different AGN feedback models: (1) no black hole and no AGN feedback; (2) thermal AGN feedback; and (3) mechanical and radiative AGN feedback. The last model is motivated by observations of broad line quasars which show winds with initial velocities of $v_w \ge$ 10,000 km/s and also heating associated with the central AGN X-ray radiation. The primary changes in gas properties due to mechanical AGN feedback are lower thermal X-ray luminosity from the final galaxy - in better agreement with observations - and galactic outflows with higher velocity $\sim 1000$ km/s similar to recent direct observations of nearby merger remnants. The kinetic energy of the outflowing gas is a factor of $\sim$ 20 higher than in the thermal feedback case. All merger remnants with momentum-based AGN feedback with $v_w \sim 10,000$ km/s and $ε_w=2 \times 10^{-3}$, independent of their progenitor mass-ratios, reproduce the observed relations between stellar velocity dispersion and black hole mass ($M_{\rm bh} - σ$) as well as X-ray luminosity ($L_X - σ$) with $10^{37.5}$ erg/s $\lesssim L_X (0.3-8~{\rm keV}) \lesssim 10^{39.2}$ erg/s for velocity dispersions in the range of 120 km/s $\lesssim σ\lesssim$ 190 km/s. In addition, the mechanical feedback produces a much greater AGN variability. We also show that gas is more rapidly and impulsively stripped from the galactic centres driving a moderate increase in galaxy size and decrease in central density with the mechanical AGN feedback model.

Explore related subjects

astro-ph.CO

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Ena Choi, Thorsten Naab, Jeremiah P. Ostriker, Peter H. Johansson, Benjamin P. Moster. 2014-03-10. Consequences of Mechanical and Radiative Feedback from Black Holes in Disc Galaxy Mergers. https://doi.org/10.1093/mnras%2Fstu874

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Revisiting Constraints on Primordial Curvature Power Spectrum from PBH Abundances

Primordial black holes (PBHs) can form in the early Universe, during radiation domination, from the collapse of large-amplitude density perturbations shortly after horizon re-entry. This mechanism establishes an approximate one-to-one correspondence between the PBH mass and the scale of the peak in the primordial curvature perturbations. Consequently, the constraints on PBH abundances can be translated into upper limits on the amplitude of the primordial curvature power spectrum, providing an indirect probe of the last e-folds of inflation corresponding to these smaller scales. We derive constraints on the amplitude of primordial curvature power spectra with both narrow and broad peaks using up-to-date bounds on PBH abundances. Given the theoretical uncertainties in PBH formation, we systematically compare the constraints obtained using the Press-Schechter (PS) formalism and peak theory, accounting for the nonlinear relation between curvature perturbations and density contrast, and assess the impact of different window functions and the transfer function. We quantify the impact of spherical versus nonspherical collapse criteria and show that including non-sphericity significantly increases the inferred amplitude of the primordial power spectrum, reflecting the larger threshold density contrast required for PBH formation. We also find that whereas the constraints obtained using the PS formalism and peak theory remain largely similar for the monochromatic case, they differ in the case of a broad primordial power spectrum. This discrepancy underscores that current constraints remain sensitive to the choice of statistical formalism. Our consistent treatment of monochromatic and extended mass functions provides a systematic mapping based on existing methodologies, while highlighting that reducing these theoretical uncertainties is a crucial step toward probing the early Universe through PBHs.

astro-ph.CO↗
arXiv2026

Analytic and numerical study of dark matter halos in the Horndeski theory

The models of modified gravity that can explain the late-time accelerated expansion of the Universe must pass the local tests of gravity, introducing a screening mechanism so that any additional fifth force in gravity is suppressed at stellar scales. Dark matter halos, in contrast, by their extendedness in scale, may exhibit a transition of screening to small scales, providing a probe of modified gravity and the origin of the late-time acceleration. We perform comprehensive studies of dark matter halos with Vainshtein screening in the Horndeski theory. Given that dark matter is cold and a dark matter halo is spherically symmetric, we analytically clarify the conditions for the halo profile under which the Vainshtein screening works effectively. We find that the Vainshtein screening is less effective even within the Vainshtein radius as the profile approaches a core-like structure around the center of a halo, which motivates us to postulate that some features owing to the fifth force can survive during the dynamical evolution of a halo. We numerically examine our postulate by a $N$-body simulation for an isolated halo with the assumption of Newtonian two-body interactions with the spherical external fifth force. We make use of three proxies of the mass through hydrostatic dynamics, the Jeans equation, and gravitational lensing, all of which must be identical in the case of Newtonian gravity as a weak-field approximation to General Relativity. We find that these proxies can be biased relative to each other at a (quasi) equilibrium, quantitatively indicating that the fiducial model of gravity is not Newtonian. Our result affirmatively suggests that multiple mass proxies from observations are capable of testing gravity on halo scales.

astro-ph.CO↗
arXiv2026

Mock Catalogs of Strongly Lensed Gravitational Waves via a Halo Model Approach with Space-borne Detectors

Future space-borne gravitational-wave (GW) detectors, such as LISA and DECIGO, are expected to detect a large number of GW events, a fraction of which may be strongly lensed by intervening galaxies or galaxy clusters. In this work, we develop a comprehensive framework to simulate strongly lensed GWs in the context of space-borne detectors. Based on realistic astrophysical models for both the source population and the lens distribution, we construct mock catalogs of lensed GW events, referred to as \textbf{GW-LMC-Space}. Our results show that, for a four-year LISA observation, the expected number of lensed events ranges from $0$ to $131$, depending on the adopted formation model of massive black hole binaries (MBHBs). The corresponding lensing probability for MBHBs can reach up to $\sim 0.3\%$. For DECIGO, we find that the number of lensed events in a one-year observation is expected to lie in the range of $0$--$44$, with a lensing probability of $\sim 0.15\%$ for stellar-mass binary black holes (BBHs), binary neutron stars (BNSs), and neutron star--black hole binaries (NSBHs). We further show that the overlap of lensed signals is a common feature in space-borne detectors, which can significantly affect both the signal-to-noise ratio (SNR) estimation and event identification. These results highlight the importance of accounting for signal overlap in the analysis of strongly lensed GW events in future space-borne GW observations.

astro-ph.CO↗