Dust lane early-type galaxies: linking AGN and star formation

Stanislav Shabala University of Oxford

with: Yuan Sen Ting (Ecole Polytechnique) Sugata Kaviraj (Imperial/Oxford) Galaxy Zoo citizen scientists Co-evolution of galaxies and BHs

Haring & Rix 2004, ApJ 604, L89

Franceschini et al. 1999 , MNRAS 310, L5 Merger-driven star formation

Kaviraj et al. 2010, arXiv: 1001.2141 Merger-driven star formation

Kaviraj et al. 2010, arXiv: 1001.2141

Hopkins et al. 2010, ApJ 715, 202 Dust lane early type galaxies Dust lane early type galaxies

65% disturbed

32% of ETGs disturbed AGN diagnostics

Seyfert

LINER Star forming

Transion Control samples Control samples

Baldry et al. 2004, ApJ 600, 681 AGN fraction Radio AGN identification Radio luminosity functions Radio luminosity functions Radio luminosity functions Radio luminosity functions

89% BPT AGN 29% BPT AGN Starburst ages

Kaviraj 2009, MNRAS 394, 1167 Starburst ages

Kaviraj 2010 Evolutionary sequence Evolutionary sequence Stellar ages AGN ages AGN ages Minor merger Quenching of SF ≤ 150‐200 Myrs

AGN triggered ≈50‐100 Myrs Why dust lanes? Why dust lanes?

100 < t2 / Myrs < 400 Star formation rates AGN fuelling AGN fraction AGN fraction

Dust lane = Extra gas?? Summary

• Dust lane ETGs a proxy for gas-rich minor mergers – AGN fraction independent of environment – Dust origin external • Star formation  SF+AGN  AGN • Enhanced star formation and AGN activity – Dust a proxy for extra gas?

Radio AGN identification Dust masses

Milky Way internal Dust masses Dust fraction Dust fraction Dust fraction

Diffusion ‐1 tdiff ≈ R / cs ≈ few kpc / 10 km s = few 100 Myrs Dust fraction

Diffusion ‐1 tdiff ≈ R / cs ≈ few kpc / 10 km s = few 100 Myrs

Destrucon 2 dMdust/dt = (dE/dt)/vshock

= 8.8 × SFR 9  remove 10 Msun in 400 Myrs Environments IRAS detections IRAS luminosities Radio - optical matching P-D distribution