The gamma-ray emitting region of the jet in Cyg X-3

Abstract

We study models of the gamma-ray emission of Cyg X-3 observed by Fermi. We calculate the average X-ray spectrum during the gamma-ray active periods. Then, we calculate spectra from Compton scattering of a photon beam into a given direction by isotropic relativistic electrons with a power-law distribution, both based on the Klein-Nishina cross section and in the Thomson limit. Applying the results to scattering of stellar blackbody radiation in the inner jet of Cyg X-3, we find that a low-energy break in the electron distribution at a Lorentz factor of ~ 300--1000 is required by the shape of the observed X-ray/gamma-ray spectrum in order to avoid overproducing the observed X-ray flux. The electrons giving rise to the observed \g-rays are efficiently cooled by Compton scattering, and the power-law index of the acceleration process is ~ 2.5--3. The bulk Lorentz factor of the jet and the kinetic power before the dissipation region depend on the fraction of the dissipation power supplied to the electrons; if it is ~ 1/2, the Lorentz factor is ~ 2.5, and the kinetic power is ~ 10^38 erg/s, which represents a firm lower limit on the jet power, and is comparable to the bolometric luminosity of Cyg X-3. Most of the power supplied to the electrons is radiated. The broad band spectrum constrains the synchrotron and self-Compton emission from the gamma-ray emitting electrons, which requires the magnetic field to be relatively weak, with the magnetic energy density < a few times 10^-3 of that in the electrons. The actual value of the magnetic field strength can be inferred from a future simultaneous measurement of the IR and gamma-ray fluxes.

MNRAS, in press, 13 pages

References in corpus (11)

• On the structure of relativistic collisionless shocks in electron-ion plasmas
• Gamma-ray binaries: pulsars in disguise ?
• Opening angles, Lorentz factors and confinement of X-ray binary jets
• Effects of the stellar wind on X-ray spectra of Cygnus X-3
• Discovery of the low-energy cutoff in a powerful giant radio galaxy
• The nature of the hard state of Cygnus X-3
• Spectral variability in Cygnus X-3
• Hadronic model for radio-to-TeV gamma-ray emission from PSR B1259-63
• The 2010 May Flaring Episode of Cygnus X-3 in Radio, X-Rays, and γ-Rays
• The aperiodic broad-band X-ray variability of Cygnus X-3
• Gamma-rays from anisotropic IC e^{\pm} pair cascades in microquasars: Application to Cyg X-3

Cited by in corpus (33)

• Gamma-ray binaries and related systems
• Science with e-ASTROGAM (A space mission for MeV-GeV gamma-ray astrophysics)
• A giant radio flare from Cygnus X-3 with associated Gamma-ray emission
• The MeV spectral tail in Cyg X-1 and optically-thin emission of jets
• Modelling the light curves of PSR B1259-63/LS 2883-II.The effects of anisotropic pulsar wind and Doppler-boosting
• A comprehensive study of high-energy gamma-ray and radio emission from Cyg X-3
• The hypersoft state of Cygnus X-3 - A key to jet quenching in X-ray binaries?
• Jet models for black-hole binaries in the hard spectral state
• The AGILE monitoring of Cygnus X-3: transient gamma-ray emission and spectral constraints
• Energy-dependent orbital modulation of X-rays and constraints on emission of the jet in Cyg X-3
• Discerning the $\gamma$-ray emitting region in the flat spectrum radio quasars
• The physical properties of $Fermi$-4LAC flat spectrum radio quasars
• Formation of recollimation shocks in jets of high-mass X-ray binaries
• 2006 May-July Major Radio Flare episodes in Cygnus X-3: spectro-timing analysis of the X-ray data
• Hadronic Gamma-Ray and Neutrino Emission from Cygnus X-3
• Core shift effect in blazars
• The Properties of Parsec-Scale Blazar Jets
• The jet kinetic power, distance and inclination of GRS 1915+105
• A search for very high-energy flares from the microquasars GRS 1915+105, Circinus X-1, and V4641 Sgr using contemporaneous H.E.S.S. and RXTE observations
• Jets in the soft state in Cyg X-3 caused by advection of the donor magnetic field and unification with low-mass X-ray binaries
• Compton scattering of blackbody photons by relativistic electrons
• Inverse Compton Emission from Relativistic Jets in Binary Systems
• High energy gamma-ray emission from compact galactic sources in the context of observations with the next generation Cherenkov Telescope Arrays
• Testing jet geometries and disk-jet coupling in the neutron star LMXB 4U 0614+091 with the internal shocks model
• Spectrum of jet emitting disc: Application to microquasar XTE J1118+480
• Scale invariant jets: from blazars to microquasars
• Microquasar Cyg X-3 -- a unique jet-wind neutrino factory?
• NuSTAR and XMM-Newton observations of the binary 4FGL J1405.1-6119. A $\gamma$-ray emitting microquasar?
• Galactic transient sources with the Cherenkov Telescope Array Observatory
• State-Dependent Orbital Modulation of X-rays in CYG X-3
• HAWC Search for High-Mass Microquasars
• Broadband Emission Spectra from the Cygnus X-3 Jet in the Soft Spectral State
• Synergies in extragalactic and Galactic jet research