New Astronomy Reviews 47 (2003) 467–469 www.elsevier.com / locate / newastrev Discovery of X-ray jets in GPS sources a, d c * Aneta Siemiginowska , Carlo Stanghellini , Gianfranco Brunetti , Tom a b a a L. Aldcroft , Jill Bechtold , Martin Elvis , D.E. Harris a Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA b Steward Observatory, University of Arizona, Tuscon, AZ, USA c CNR, Bologna, Italy d CNR, Noto, Italy Abstract Giga-Hertz Peaked Spectrum (GPS) and Compact Steep Spectrum (CSS) sources have compact radio morphologies (,1 to 10 kpc, respectively). They have been interpreted as either young counterparts of FR I radio galaxies or as ‘frustrated’ AGN, in which the radio jets are not able to penetrate the host galaxy’s gas and dust. The high spatial resolution of Chandra allows us to study the environment of these sources within arcsec of the strong compact core. Here, we present the discovery of X-ray jets in the two GPS quasars, indicating that X-ray emission associated with relativistic plasma is present at large distances from the GPS quasar.  2003 Elsevier B.V. All rights reserved. Keywords: Quasars: individual (PKS11272145, B2 07381313); Galaxies: jets; X-rays: galaxies 1. Introduction strong X-ray emission via inverse Compton (IC) scattering of the Cosmic Microwave Background The unprecedented sub-arcsecond resolution ( Van Radiation (CMB). Both the high bulk velocity of the Speybroeck et al., 1997) of the Chandra X-ray jets and the increased energy density of the CMB 4 Observatory ( Weisskopf et al., 2002) gives us, for radiation (as (1 1 z) ) contribute to the final X-ray the first time, the opportunity to study details of the intensity so that X-rays may be a good indicator of X-ray structures in the vicinity of AGN and quasars. the large scale environment associated with quasars Discoveries of X-ray jets associated with many radio at high redshift. sources show that the jets are quite common. Recent Giga-Hertz Peaked Spectrum (GPS) and Compact X-ray observations with Chandra ( Tavecchio et al., Steep Spectrum (CSS) sources are usually compact 2000; Celotti et al., 2001; Brunetti et al., 2002, ( , 1–10 kpc; see O’Dea, 1998 for review). Only a Sambruna et al., 2002; Schwartz et al., 2000; few GPS / CSS sources show large scale Mpc radio Siemiginowska et al., 2002) have shown that if structures ( Baum et al., 1990, Stanghellini, 1997, 3 relativistic electrons with g | 10–10 are present in a Schoenmakers et al., 1999). The detection of extend- jet with high bulk velocity then it can result in a ed radio emission in the vicinity of a strong core requires high dynamic range observations. X-ray detection can reveal the presence of such structures *Corresponding author. Fax: 11-617-495-7105. and can allow for differentiation between truly E-mail address: asiemiginowska@cfa.harvard.edu (A. Siemiginowska). compact and ‘extended’ sources within the GPS / 1387-6473 / 03 / $ – see front matter  2003 Elsevier B.V. All rights reserved. doi:10.1016 / S1387-6473(03)00073-3