AGN hosts at z < 0.05 are not predominantly fueled by galactic bars

Presentation of Galaxy Zoo 2 research at the National Astronomy Meeting (NAM2014) in Portsmouth, UK. Jun 24, 2014

Transcript

1. AGN hosts at z < 0.05 are not predominantly fueled by galactic bars Kyle Willett University of Minnesota, USA NAM 2014 with: Melanie Galloway Lucy Fortson Karen Masters Kevin Schawinski Carie Cardamone Edmond Cheung and the GZ2 volunteers @kwwillett
2. What controls the number of disk galaxies with actively accreting black holes (AGN)?
3. Previous studies of the bar-AGN relationship have conflicting results Numerical simulations do predict bar-driven fueling, with efficiency proportional to bar strength (Athanassoula 92, Friedli+93; Regan+04) Athanassoula 92
4. Previous studies of the bar-AGN relationship have conflicting results Bars do efficiently drive gas toward the centers of galaxies, as traced by central star formation (Heckman 80, Hummel+90, Ho+97, Hunt+99, Hao+09, Ellison+11, Cheung+2013) Numerical simulations do predict bar-driven fueling, with efficiency proportional to bar strength (Athanassoula 92, Friedli+93; Regan+04) Ellison+11
5. Previous studies of the bar-AGN relationship have conflicting results Bars do efficiently drive gas toward the centers of galaxies, as traced by central star formation Hummel+90, Ho+97, Hunt+99, Hao+09, Ellison+11, Cheung+2013) Numerical simulations do predict bar-driven fueling, with efficiency proportional to bar strength (Athanassoula 92, Friedli+93; Regan+04) Some observational studies detected increased bar fractions in AGN hosts. (Ho+97; Laurikainen+04; Hao+09; Oh+12, Alonso+13) Other work, however, found no such relationship. (Mulchaey+97; Marquez+00; Martini +03; Lee+12) Lee+12 Oh+12
6. Willett et al. (2013); http://data.galaxyzoo.org and DR10 The Galaxy Zoo 2 project provides detailed morphological classifications for more than 300,000 galaxies in the SDSS
7. pbar = 0.00 pbar = 0.35 pbar = 0.65 pbar = 0.11 pbar = 0.55 pbar = 1.00 pbar = 1.00 pbar = 0.25 pbar = 0.55
8. AGN LINER comp SF
9. AGN LINER comp SF
10. AGN LINER comp SF
11. ➢ Both AGN and bars are more common in galaxies with high mass and red colors ! ➢ Must analyze differences between barred and unbarred AGN fractions at fixed mass and color 1.0 1.5 2.0 2.5 3.0 3.5 All Disks N=19,756 1.0 1.5 2.0 2.5 3.0 Barred Disks N=8,186 9.0 9.5 10.0 10.5 11.0 1.0 1.5 2.0 2.5 3.0 Unbarred Disks N=11,570 9.0 9.5 10.0 10.5 11.0 11.5 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 Stellar Mass log(M/M ) 0.0(u r) colour AGN fraction
12. 9.0 9.5 10.0 10.5 11.0 11.5 Stellar Mass log(M/M ) 1.0 1.5 2.0 2.5 3.0 3.5 0.0(u r) colour 0.10 0.08 0.06 0.04 0.02 0.00 0.02 0.04 0.06 0.08 0.10 barred AGN fraction unbarred AGN fraction
13. 9.0 9.5 10.0 10.5 11.0 11.5 Stellar Mass log(M/M ) 1.0 1.5 2.0 2.5 3.0 3.5 0.0(u r) colour 0.10 0.08 0.06 0.04 0.02 0.00 0.02 0.04 0.06 0.08 0.10 barred AGN fraction unbarred AGN fraction µ > 6 ⇥ 10 3, = 4 ⇥ 10 2 p > 95% 0.0 0.2 0.4 0.6 0.8 1.0 Fraction of bins Greater unbarred AGN fraction Greater barred AGN fraction
14. 9.5 10.0 10.5 11.0 11.5 Stellar Mass log(M/M ) 1.5 1.0 0.5 0.0 0.5 1.0 1.5 2.0 2.5 Eddington Ratio log(L[OIII ] /MBH [M /L ]) 1.5 2.0 2.5 3.0 3.5 0.0(u r) colour Barred Unbarred p = 0.16
15. ➢ Using visual classifications of disks from Galaxy Zoo 2, there is a small increase in the AGN fraction at fixed mass and color when a strong bar is present (1.5 σ). ! ➢ The Eddington ratio of the central black hole is unaffected by the presence of a galactic bar. ! ➢ While bars do influence the secular evolution of galaxies, bar-driven fueling is likely only one of several mechanisms taking place in the AGN. Urry & Padovani (1995)