1. Radiative Efficiency and Content of Extragalactic Radio Sources Laura Bîrzan Collaborators: Brian McNamara (U. Waterloo), Paul Nulsen (CfA), Chris Carilli (NRAO), Mike Wise (U. Amsterdam)

2. Radiative Efficiency / Scaling Relations An understanding of how scales with is important in order to estimate AGN feedback across a wide range of environments and masses ( e.g., Magliocchetti & Bruggen 2007, Best et al. 2007 ). Our first attempt ( Bîrzan et al. 2004) : but with large scatter. Using the 5 GHz core radio luminosity, Merloni & Heinz (2007) find a tighter scaling relation. How does the lobe radio luminosity scale with the mechanical power?

3. Radio and X-ray: Complementary Data X-ray data ( Rafferty et al. 2006 ):  Measure p,V   Ages: t cav ( t buoy,t refill,t cs )  Radio data:  Synchrotron break frequency is indicative of the age R a b 330 MHz Radio Image MS 0735.6+7421 X-ray Image spectrum at t 1 spectrum at 5t 1 spectrum at t 0

4. The Sample 24 systems from Chandra Data Archive which show X-ray cavities ( Bîrzan et al. 2004, Rafferty et al. 2006 ). Redshift range: 0.0035 < z < 0.545 Radio sources associated with the central galaxy. VLA observations at 330 MHz, 1.4 GHz, 4.5 GHz and 8.5 GHz.

5. Particle Content and Aging Is the wide range in k due to aging?   Young sources tend to have smaller k.  But, range in age can not fully account for the range in k. Entrainment of heavy particles may play a role. olderyounger radio-filled cavity ghost cavity

6. Radiative Efficiencies (lower limit – shocks not included) Most objects: a~100 ( Nipoti & Binney 2005, Bicknell et al. 1997, De Young 1993 ).  Ghost cavities generally require higher a.  Scaling relations: Scatter = 0.65 dex Scatter = 0.31 dex for radio filled only radio-filled cavity ghost cavity

7. Aging and Radiative Efficiencies No clear trend is present. However, there is a tendency for younger objects to be radiatively efficient.  Aging contributes to scatter in the radiative- efficiencies plot, but can not account for all of it.  The scatter may also be due to entrainment, which would increase k and reduce L rad. radio-filled cavity ghost cavity olderyounger

8. Scaling Relations: P cav and L radio Including the dependence of the radiative efficiencies on C : Scatter is reduced by ≈50% (to 0.33 dex) However, need radio data at several frequencies radio-filled cavity ghost cavity

9. Conclusions The radiative efficiency is around 1%, but can be much lower. Scatter about scaling relation is large. Aging and entrainment may be important contributors. By accounting for differences in age (break frequency), scatter is reduced by ≈ 50%. k ( =E part /E e ) ranges between a few and a few thousands (for equipartion assumptions). Again, aging and entrainment may contribute to large range in k.

11. Radio Spectra

12. 325 and 1400 MHz Scaling Relations P 327 : Scatter = 0.75 dex P 1400 : Scatter = 0.83 dex