Chandra discovery of a 100 kiloparsec X-ray jet in PKS 0637-752

Citation
Da. Schwartz et al., Chandra discovery of a 100 kiloparsec X-ray jet in PKS 0637-752, ASTROPHYS J, 540(2), 2000, pp. L69-L72
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004-637X → ACNP
Volume
540
Issue
2
Year of publication
2000
Part
2
Pages
L69 - L72
Database
ISI
SICI code
0004-637X(20000910)540:2<L69:CDOA1K>2.0.ZU;2-O
Abstract
The quasar PKS 0637-752, the first celestial X-ray target of the Chandra X- Ray Observatory, has revealed asymmetric X-ray structure extending from 3" to 12" west of the quasar, coincident with the inner portion of the jet pre viously detected in a 4.8 GHz radio image (Tingay et al. 1998). At a redshi ft of z = 0.651, the jet is the largest (greater than or similar to 100 kpc in the plane of the sky) and most luminous (similar to 10(44.6) ergs s(-1) ) of the few so far detected in X-rays. This Letter presents a high-resolut ion X-ray image of the jet, from 42 ks of data when PKS 0637-752 was on-axi s and ACIS-S was near the optimum focus. For the inner portion of the radio jet, the X-ray morphology closely matches that of new Australian Telescope Compact Array radio images at 4.8 and 8.6 GHz. Observations of the parsec- scale core using the very long baseline interferometry space observatory pr ogram mission show structure aligned with the X-ray jet, placing important constraints on the X-ray source models. Hubble Space Telescope images show that there are three small knots coincident with the peak radio and X-ray e mission. Two of these are resolved, which we use to estimate the sizes of t he X-ray and radio knots. The outer portion of the radio jet and a radio co mponent to the east show no X-ray emission to a limit of about 100 times Lo wer flux. The X-ray emission is difficult to explain with models that succe ssfully account for extranuclear X-ray/radio structures in other active gal axies. We think the most plausible is a synchrotron self-Compton model, but this would imply extreme departures from the conventional minimum energy a nd/or homogeneity assumptions. We also rule out synchrotron or thermal brem sstrahlung models for the jet X-rays, unless multicomponent or ad hoc geome tries are invoked.