ebook img

jets in AGN PDF

59 Pages·2016·13.58 MB·English
Save to my drive
Quick download
Download
Most books are stored in the elastic cloud where traffic is expensive. For this reason, we have a limit on daily download.

Preview jets in AGN

Active Galactic Nuclei Part II: jets in AGN 3C 273 (Soldi et al. 2008) Anima6on: COSMOVISION / A. Marscher Volker Beckmann CNRS / IN2P3 Cargèse, May 25, 2016 Active Galactic Nuclei •  Active Galactic Nuclei (AGN) are efficient particle accelerators •  Jets (relativistic outflows) •  Winds (non-relativistic outflows) Credit: NASA / Ann Field (STScI) Credit: NASA / CXC / M. Weiss Jets in AGN Jets are real! Cygnus A; Carilli & Barthel (1996) 3C 273, Chandra Cen A, Fermi/LAT M87: Image courtesy of NRAO/AUI and Abdo et al. 2010 Y. Y. Kovalev, MPIfR and ASC Lebedev Centaurus A Jets appear single-sided and symmetric, visible (resolvable) from the radio to the X-ray (gamma-ray) domain Jets are ou*lows Anima1on: Lindfors et al. (2006), see Marc Türler’s website at the ISDC 3C 279 AGILE (>100 MeV), Giuliani et al. 2009 VHE MAGIC observa6on (~ TeV) Chandra X-ray image Jets in AGN •  Jets are ou*lows •  Super luminal mo6on observed (up to 40c) •  Geometric effect (Rees 1966): Mrk 421 Graphic: Beckmann & Shrader (2012) Inverse Compton 22 GHz VLBI map of 3C 279, showing apparent speed of 7.5c (Wehrle et al. 2001) Synchrotron emission •  Synchrotron emission is a strong indicator of a jet •  Fast moving, charged par6cle in magne6c field •  L (Z, B, γ, m) m /m = 1836 ! L is 3 10-7 lower for protons when p e assuming the same speed for electron and proton. Assuming same par6cle energy E (i.e. proton slower): L is lower by 9 10-14 for protons Graphic: Beckmann & Shrader (2012) Synchrotron emission in AGN jets is dominantly produced by electrons and/or positrons Lorentz factor: Protons are likely also to be accelerated, but do not contribute significantly to the synchrotron power Synchrotron emission •  Synchrotron emission depends on energy distribu6on of emikng par6cles •  Direct link between the slope p of the electron energy distribu6on and the slope α of the synchrotron spectrum (in the radio band): p = 2α + 1 •  infinite at low energies? •  Synchrotron self-absorp6on •  Synchrotron light reabsorbed by e- •  Most efficient close to cri6cal frequency of electron: Less chances to catch an electron at high E Spectrum: absorp6on coefficient (ν), B and electron popula6on isotropic… Graphic: Beckmann & Shrader (2012) Inverse Compton (IC) emission •  Rela6vis6c, charged par6cles (e.g. from plasma in jet) •  Dense photon field (e.g. from synchrotron or external field) •  Inverse Compton (IC) scauering •  quasi elas6c: Thomson scauering (E is the photon energy 1 befor the scauering, E aver the scauering) 2 ! Thomson Klein-Nishina correc6on •  Mul6ple IC scauerings possible Graphic: Beckmann & Shrader (2012) Beckmann & Shrader (2012); graphic by Marie-Luise Menzel Jets in AGN X-ray op1cal Mrk 421 γ-ray Synchrotron emission Inverse Compton Radio SED of Mrk 421 (Abdo et al. 2011, ApJ, 736, 131)

Description:
Winds (non-relativistic outflows). Credit: NASA (2006), see Marc TŘrler's website at the ISDC . Andrea Tramacere: h p://www.isdc.unige.ch/sedtool/
See more

The list of books you might like

Most books are stored in the elastic cloud where traffic is expensive. For this reason, we have a limit on daily download.