The COS-Holes Survey: Connecting Galaxy Black Hole Mass with the State of the CGM

Abstract

We present an analysis of Hubble Space Telescope COS/G160M observations of C IV in the inner circumgalactic medium (CGM) of a novel sample of eight z ∼ 0, L ≈ L ^⋆ galaxies, paired with UV-bright QSOs at impact parameters ( R _proj ) between 25 and 130 kpc. The galaxies in this stellar-mass-controlled sample (log _10 M _⋆ / M _⊙ ∼ 10.2–10.9 M _⊙ ) host supermassive black holes (SMBHs) with dynamically measured masses spanning log _10 M _BH / M _⊙ ∼ 6.8–8.4; this allows us to compare our results with models of galaxy formation where the integrated feedback history from the SMBH alters the CGM over long timescales. We find that the C IV column density measurements ( N _C IV ; average log _10 N _C IV,CH = 13.94 ± 0.09 cm ^−2 ) are largely consistent with existing measurements from other surveys of N _C IV in the CGM (average log _10 N _C IV,Lit = 13.90 ± 0.08 cm ^−2 ), but do not show obvious variation as a function of the SMBH mass. By contrast, specific star formation rate (sSFR) is highly correlated with the ionized content of the CGM. We find a large spread in sSFR for galaxies with log _10 M _BH / M _⊙ > 7.0, where the CGM C IV content shows a clear dependence on galaxy sSFR but not M _BH . Our results do not indicate an obvious causal link between CGM C IV and the mass of the galaxy’s SMBH; however, through comparisons to the EAGLE, Romulus25, and IllustrisTNG simulations, we find that our sample is likely too small to constrain such causality.

Keywords

• Galaxy formation
• Circumgalactic medium
• Quasar absorption line spectroscopy