Issue |
A&A
Volume 399, Number 1, February III 2003
|
|
---|---|---|
Page(s) | 91 - 97 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20021772 | |
Published online | 05 February 2003 |
Chandra detection of hotspot and knots of 3C 303
1
Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan
2
Institute of Space and Astronautical Science, Sagamihara, Kanagawa, Japan
3
Laboratory for High Energy Astrophysics, NASA/GSFC, Greenbelt, MD, USA
4
Department of Earth and Space Science, Osaka University, Osaka, Japan
5
Landessternwarte Heidelberg, Königstuhl, Heidelberg, Germany
Corresponding author: J. Kataoka, kataoka@hp.phys.titech.ac.jp
Received:
17
October
2002
Accepted:
27
November
2002
We report the detection at X-rays of the radio/optical hotspot and
knots of 3C 303 from a short (15 ksec) Chandra exposure in 2001
March. The X-ray morphology is similar to that of the radio/optical
emission with peaks in the X-ray emission found at 5.5'' (knot B), 9''
(knot C) and 17'' (hotspot) from the core of 3C 303.
Despite the limited signal-to-noise ratio of the short Chandra
exposure, the X-ray photon spectrum was measured for the hotspot.
We construct the spectral energy distribution (SED) and find that
the X-ray flux is well below the extrapolation of the radio-to-optical
continuum, which we interpret as resulting from the production of X-rays
via inverse Compton scattering of both synchrotron photons (SSC) and
cosmic microwave background photons (EC/CMB).
The magnetic field strength, region size, and the maximum energy
of electrons are self-consistently determined for the hotspot
to be G,
cm,
and
.
This implies a magnetic field strength a factor of ~30
below the equipartition value;
G.
The origin of this large departure from equipartition is still uncertain,
but the discrepancy is reduced if the plasma in the hotspot is
moving with mildly relativistic speeds.
Our observation of 3C 303, as well as recent Chandra detections of
large scale jets and hotspots in a number of radio galaxies,
confirm that particles are accelerated very efficiently in radio galaxies.
Key words: galaxies: active / galaxies: individual: 3C 303 / galaxies: jets / X-rays: galaxies
© ESO, 2003
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.