User:Pmarecki/Jets

Polarization
MOJAVE Paper:

Can polarization be generated by the Faraday effect? (Different propagation speeds for both polarizations.) This has already been studied (for polarization vectors; not waves (?)) by Obukhov,. It is related to the Birch rotation.

Time Variability


- very high TeV variability (minutes?)
 * Scales

Fermi:
 * Coincidences (Radio-/TeV)


 * Propagation of knots -- "superluminal motion", but .... ~4c ...standard formula for source with v=c is (apparent speed) v=c*Sin(θ)/[1-Cos(θ)]. The dependence is monotonic: 1.5c@65°, 2c@55°, 3c@35°, 4c@28°, 5c@23°, 6c@18°.


 * The orientation of the M87 jet is almost determined by the 6c apparent velocities measured in it ( Science 325 444 (2009), estimate of the angle θ to 15°-25°)

Messier_87

 * edge brightened
 * 0.5mas=70R (R=Rs)
 * current resolution ~30R (przeliczyc VLBI@ SgrA* - 30μas - oszacować mozliwosci)
 * gamma variability ~days
 * outburst Feb'08: causality arguments -- outburst in ~5R
 * correlation of all frequencies for the outburst (at the core, not at knots)
 * during the flare the centrum of the core did not move by more than ~6R -- really central object active
 * gamma cannot escape due to high probability of e+e- production
 * there was also 2005 flare
 * Main Point: TeV from the Jet Collimation region close to the BH

3C_273

 * Jet at 9c
 * variability from radio to X-ray on short time scales
 * knots
 * coincident polarization in all frequencies
 * stuidies of polarization map:
 * detailed, recent studies, particles with 10^{19} TeV
 * Faraday rotation decreases (depolarization increases) towards the core,

In this model, the bulk velocity of the jet is assumed to be highly relativistic all the way to nearly megaparsec distances, with a Doppler factor of g ~ 10. Applying the beamed IC model to a large sample of Chandra-detected quasar jets, Kataoka & Stawarz (2005) found a range of 4 < g < 16 for ~ 90% of the sources."
 * "A widely discussed hypothesis for the strong X-ray emission is relativistically enhanced inverse Compton (IC) scattering off the cosmic microwave background (CMB) photons.

Cygnus A
(large θ)


 * are superluminal motions of knots also observed?

Questions
* are emissions always more energetic closer to the object, and more-radio closer to the end of the jet?

Resources
Project MOJAVE

Project XJET