Quick search Find article
Quick search
Find article

ORIGIN OF THE X-RAYS AND POSSIBLE GeV-TeV EMISSION FROM THE WESTERN HOT SPOT OF PICTOR A

FREE ISSUE

Jin Zhang1,2,3, J.-M. Bai1, Liang Chen1,3 and Xian Yang1

Show affiliations


Pictor A is a nearby Fanaroff-Riley class II (FR II) radio galaxy with a bright hot spot, the western hot spot. Observation of high polarization in the optical emission of the hot spot indicates that the optical emission could be synchrotron radiation of relativistic electrons in the hot spot. These electrons may be able to produce high-energy γ-ray photons through inverse Compton scattering. We use single-zone and multizone synchrotron + synchrotron self-Compton models to fit the observed spectral energy distribution (SED) from the radio to the X-ray band of the hot spot. Our results show that in the case of a much weaker magnetic field strength than the equipartition magnetic field, both the single-zone and multizone models can fit the SED, but the multizone model significantly improves the fit. The two models predict the hot spot as a GeV-TeV source, which might be marginally detectable with Fermi/LAT and H.E.S.S. The inverse Compton scattering of cosmic microwave background is also considered, but its contribution to GeV-TeV emission is negligible. Note that under the equipartition condition, the SED can also be fitted with the multizone model, but the predicted flux at >1022 Hz is too weak to be detectable. The detection of TeV γ-rays from this FR II radio galaxy, if confirmed, would establish a new subclass of extragalactic sources in this energy regime since most of the active galactic nuclei detected to date at TeV energies are high-energy-peaked BL Lac objects.


Keywords

galaxies: individual (Pictor A); gamma rays: theory; radiation mechanisms: non-thermal; X-rays: galaxies


Dates

Issue 1 (2009 August 10)

Received 2009 March 16, accepted for publication 2009 May 28

Published 2009 July 23



  1. Origin of the X-rays and Possible GeV-TeV Emission from the Western Hot Spot of Pictor A

    Jin Zhang et al. 2009 ApJ 701 423

  2. Experimental results on hard x-ray energy emitted by a low-energy plasma focus device: a radiographic image analysis

    Marcelo Zambra et al 2009 Plasma Phys. Control. Fusion 51 125003

  3. The exponential map for the unitary group SU(2,2)

    A O Barut et al 1994 J. Phys. A: Math. Gen. 27 6799

  4. Sulfur K-edge XANES spectroscopy as a tool for understanding sulfur chemical state in anaerobic granular sludge

    E van Hullebusch et al 2009 J. Phys.: Conf. Ser. 190 012184

  5. An ultra-violet microscope for the examination of opaque objects

    B K Johnson 1934 J. Sci. Instrum. 11 384

  6. In-situ investigation of Bi thin film condensation by surface sensitive X-ray absorption spectroscopy at cryogenic temperatures

    D Lützenkirchen-Hecht et al 2009 J. Phys.: Conf. Ser. 190 012114

  7. Optical contrast in ion-implanted amorphous silicon carbide nanostructures

    S Takahashi et al 2007 J. Phys. D: Appl. Phys. 40 7492

  8. Optical indicator

    P J Kipp and Zonen 1934 J. Sci. Instrum. 11 396

  9. Resonance-induced effects in photonic crystals

    Alexander Moroz and Adriaan Tip 1999 J. Phys.: Condens. Matter 11 2503

  10. Non-tilting out-of-plane mode high-Q mechanical silicon oscillator

    O Hahtela et al 2005 J. Micromech. Microeng. 15 1848

Users also read

What's this?
This innovative new feature generates a list of articles 'also read' by other users based on them reading the original article. Article abstracts citations and references are all considered and weighted accordingly. We hope that this will help you find relevant papers for your research.

  1. X-Ray Radiation Mechanisms and Beaming Effect of Hot Spots and Knots in Active Galactic Nuclear Jets

View by subject




Export








Please login to access our web services, or create an account if you don't yet have one.

You must have cookies enabled in your web browser to be able to login.

Username
Password

Forgotten your password? Get a new one here.