Markos Georganopoulos1,2

David Rivas1,3

1 University of Maryland, Baltimore County2 NASA Goddard Space Flight Center

3Johns Hopkins University

SUPER-EDDINGTON JETS ARE REQUIRED TO EXPLAIN THE BRIGHTEST BLAZAR FLARES

THE CASE OF THE TEV FSRQ 4C 21.35 (PKS 1222+21)

Bolometric flare luminosity assuming isotropy: Liso=3x1048 erg s-1 (Tanaka et al. 2011)

MBH=6x108 M, Ledd=8x1046 erg s-1 (Farina et al. 2012)

Aleksic et al. 2011

Ghisellini et al. 2010 δ=Γ=20, from βapp =10-26 (Lister 2010,13)

So, during major flares, the released photons can carry a significant fractionof the Eddington Luminosity.

Focus on the most economic jets: no hadrons

Q: How much electron jet power do we need to produce that much photon power?

A: If we can ‘burn’ the leptons efficiently (fast cooling) we just need

Bur if we cannot (slow cooling) we need significantly more power

Q: What determines the cooling regime?A: The blazar location

10-20 pc, away from all photon fields (from multi-wavelength studies of Marscher’s group).

Slow cooling, super-Eddington flaring jet

Sub-pc or pc scales. Fast cooling on the UV broad line photons (0.1 pc) or Fast cooling on the IR photons of the molecularTorus (~1 pc).

In both cases the jet electron power issub-Eddington.

Q: Can the flare of PKS 1222-21 take place in the broad line region?

A: No. The MAGIC sub-TeV photons would have been absorbed due to pair production on the UV broad line region photons.

Q: So, can the flare of PKS 1222-21 take place in the molecular torus?

Then a sub-Eddington power in leptons would suffice to produce the flare.

A: We need to check if a jet that carries only radiating leptons will deceleratedue to Compton drag.

This was checked by Ghisellini & Tavecchio (2010)for the case of BLR emission and was found to be significant.

emeN

pmpN

bulk

c

U

dl

d22

2e

T

m 9

16-

Two couple equations describe Compton drag:

21

10 1)(

lll dec 2

11

0maxmax 1)( lll dec

pcUldec1

4,0041.0

Analytical solution for monoenergetic electrons with no protons :

Comparing our numerical solutionto the analytical:

Accretion luminosity: Lacc=5x1046 erg s-1 (Tavecchio et al 2011).

Even for Ljet=LEdd, the jet decelerate significantly.

It takes a 2LEdd jet to avoid significant deceleration

How much jet power do we need to avoid significant deceleration?

CONCLUSIONS:

1. Bright blazar flares carry an angle-integrated photon power that can reach a significant fraction of LEdd.

2. If such flares take place in environements without substantial external photon fields, as expected at 10-20 pc, the cooling is slow and the jet power, even just considering leptons, is super-Eddington. 3. If such flares take place in an environment like the molecular torus or the broad line region, where ample photons permeate the jet, cooling is slow and the lepton power required is equal to the angle-integrated photon power.

4. In this case, however, such a jet containing only leptons will decelerate substantially, contrary to VLBI observations that record highly superluminal motions.

5. To address this issue, a non-leptonic component is required, such that the total jet power becomes equal or higher than the Eddington luminosity.

NO MATTER WHERE BRIGHT FLARES OCCUR, THEY REQUIRE SUPER-EDDINGTON JETS