1 / 12

Radiative Efficiency and Content of Extragalactic Radio Sources

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). Radiative Efficiency / Scaling Relations.

gridley
Download Presentation

Radiative Efficiency and Content of Extragalactic Radio Sources

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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 R spectrum at t0 a b spectrum at t1 spectrum at 5t1 MS 0735.6+7421 • X-ray data (Rafferty et al. 2006): • Measure p,V • Ages: tcav (tbuoy,trefill,tcs ) X-ray Image MS 0735.6+7421 • Radio data: • Synchrotron break frequency is indicative of the age 330 MHz Radio Image

  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. 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 ink. Entrainment of heavy particles may play a role. Particle Content and Aging radio-filled cavity ghost cavity older younger

  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. 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 Lrad. Aging and Radiative Efficiencies radio-filled cavity ghost cavity older younger

  8. Scaling Relations: Pcav and Lradio • 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 (=Epart/Ee) ranges between a few and a few thousands (for equipartion assumptions). • Again, aging and entrainment may contribute to large range in k.

  10. Radio Spectra

  11. 325 and 1400 MHz Scaling Relations • P327: Scatter = 0.75 dex • P1400: Scatter = 0.83 dex

More Related