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arXiv · 1710.04225

Decoupled Black Hole Accretion and Quenching: The Relationship Between BHAR, SFR, and Quenching in Milky Way and Andromeda-mass Progenitors Since z = 2.5

Michael J. Cowley·Lee R. Spitler·Ryan F. Quadri·Andy D. Goulding·Casey Papovich·Kim-Vy H. Tran·Ivo Labbe·Leo Alcorn·Rebecca J. Allen·Ben Forrest·Karl Glazebrook·Glenn G. Kacprzak·Glenn Morrison·Themiya Nanayakkara·Caroline M. S. Straatman·Adam R. Tomczak
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Abstract

We investigate the relationship between the black hole accretion rate (BHAR) and star-formation rate (SFR) for Milky Way (MW) and Andromeda (M31)-mass progenitors from z = 0.2 - 2.5. We source galaxies from the Ks-band selected ZFOURGE survey, which includes multi-wavelenth data spanning 0.3 - 160um. We use decomposition software to split the observed SEDs of our galaxies into their active galactic nuclei (AGN) and star-forming components, which allows us to estimate BHARs and SFRs from the infrared (IR). We perform tests to check the robustness of these estimates, including a comparison to BHARs and SFRs derived from X-ray stacking and far-IR analysis, respectively. We find as the progenit- ors evolve, their relative black hole-galaxy growth (i.e. their BHAR/SFR ratio) increases from low to high redshift. The MW-mass progenitors exhibit a log-log slope of 0.64 +/- 0.11, while the M31-mass progenitors are 0.39 +/- 0.08. This result contrasts with previous studies that find an almost flat slope when adopting X-ray/AGN-selected or mass-limited samples and is likely due to their use of a broad mixture of galaxies with different evolutionary histories. Our use of progenitor-matched samples highlights the potential importance of carefully selecting progenitors when searching for evolutionary relationships between BHAR/SFRs. Additionally, our finding that BHAR/SFR ratios do not track the rate at which progenitors quench casts doubts over the idea that the suppression of star-formation is predominantly driven by luminous AGN feedback (i.e. high BHARs).

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Michael J. Cowley, Lee R. Spitler, Ryan F. Quadri, Andy D. Goulding, Casey Papovich, Kim-Vy H. Tran, Ivo Labbe, Leo Alcorn, Rebecca J. Allen, Ben Forrest, Karl Glazebrook, Glenn G. Kacprzak, Glenn Morrison, Themiya Nanayakkara, Caroline M. S. Straatman, Adam R. Tomczak. 2017-10-11. Decoupled Black Hole Accretion and Quenching: The Relationship Between BHAR, SFR, and Quenching in Milky Way and Andromeda-mass Progenitors Since z = 2.5. https://doi.org/10.1093/mnras%2Fstx2587

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