[ITAL]Chandra[/ITAL] Observations of the X-Ray Jet of 3C 273

Abstract

We report results from Chandra observations of the X-ray jet of 3C 273 during the calibration phase in 2000 January. The zeroth-order images and spectra from two 40 ks exposures with the High-Energy Transmission Grating and Low-Energy Transmission Grating ϩ Advanced CCD Imaging Spectrometer-S show a complex Xray structure. The brightest optical knots are detected and resolved in the 0.2-8 keV energy band. The X-ray morphology tracks well the optical. However, while the X-ray brightness decreases along the jet, the outer parts of the jet tend to be increasingly bright with increasing wavelength. The spectral energy distributions of four selected regions can best be explained by the inverse Compton scattering of (beamed) cosmic microwave background photons. The model parameters are compatible with equipartition and a moderate Doppler factor, which is consistent with the one-sidedness of the jet. Alternative models either imply implausible physical conditions and energetics (the synchrotron self-Compton model) or are sufficiently ad hoc to be unconstrained by the present data (synchrotron radiation from a spatially or temporally distinct particle population).

NewChandraObservations of the Jet in 3C 273. I. Softer X‐Ray than Radio Spectra and the X‐Ray Emission Mechanism

“…It is evident from the SEDs that the jet emission from radio up to X-rays cannot be explained as a single synchrotron component for any part of the jet. Except for region A, this was already known from the analysis of ROSAT data (Röser et al 2000) and of the first Chandra data sets (Marshall et al 2001;Sambruna et al 2001). Jester et al (2002 showed that a single-component synchrotron spectrum was not in fact viable for knot A, chiefly because the new multifrequency, multiconfiguration VLA data set used by them, and here, yielded substantially different radio SED shapes.…”

“…Regarding the SEDs, they came to conclusions similar to those by Röser et al (2000). Sambruna et al (2001) analyzed a smaller set of the early Chandra data and favored a beamed IC-CMB model for the emission from all parts of the jet. Marshall et al (2001) compared the optical and X-ray morphology at the Chandra resolution of 0B78 and found that the X-ray and optical emission come from the same parts of the jet and show very similar features.…”

Synthetic Observations of Simulated Radio Galaxies. I. Radio and X‐Ray Analysis

“…Most of the other LOS in the control model and the cooling model scatter The estimation of the local energy partitioning d based on B ic and B me works best in regions that are not strongly influenced by radiative aging and where the partitioning is not expected to vary strongly over short distances, such as inside jet structures. There is increasing evidence that the X-ray emission observed from some jets is Doppler-boosted IC/3K emission (e.g., Tavecchio et al 2000;Sambruna et al 2001;Celotti, Ghisellini, & Chiaberge 2001). In that case this kind of analysis could be useful still, but it would require taking beaming and boosting effects into account, which we have not done because the flows here are nonrelativistic.…”

X-rays from the jet in 3C 273: Clues from the radio–optical spectra

“…Since self-Compton scattering of the radio-optical emission can account only for a small fraction of the observed X-ray fluxes, Röser et al (2000) suggested to consider the X-rays as synchrotron emission from a second, higherenergy electron population. As an alternative, a contribution by beamed inverse Compton scattering of the cosmic microwave background has been suggested (Marshall et al 2001;Sambruna et al 2001). A distinction between these models is not possible based on the currently available X-ray data.…”