X‐Ray Properties of the Gigahertz Peaked and Compact Steep Spectrum Sources

Abstract

We present Chandra X-ray Observatory observations of gigahertz peaked-spectrum (GPS) and compact steep spectrum (CSS) radio sources. The Chandra sample contains 13 quasars and 3 galaxies, with measured 2Y10 keV X-ray luminosities within 10 42 Y10 46 erg s À1 . We detect all of the sources, five of which are observed in X-rays for the first time. We study the X-ray spectral properties of the sample. The measured absorption columns in the quasars are different from those in the galaxies in that the quasars show no absorption (with limits $10 21 cm À2 ), while the galaxies have large absorption columns (>10 22 cm À2 ) consistent with previous findings. The median photon index of the sources with a high signal-to-noise ratio is À ¼ 1:84 AE 0:24, which is larger than the typical index of radio-loud quasars. The arcsec resolution of the Chandra telescope allows us to investigate extended X-ray emission and to look for diffuse components and X-ray jets. We found X-ray jets in two quasars (PKS 1127À145 and B2 0738+32), and an X-ray cluster surrounding a CSS quasar (3C 186; z ¼ 1:1). We detected a possible binary structure in galaxy 0941À080 and an extended diffuse emission in galaxy PKS B1345+125. We discuss our results in the context of X-ray emission processes and radio source evolution. We conclude that the X-ray emission in these sources is most likely unrelated to a relativistic jet, although the sources' radio loudness may suggest a high radiative efficiency for the jet power in these sources.

Hi absorption in nearby compact radio galaxies

“…Siemiginowska et al 2008;Siemiginowska 2009;Ostorero et al 2010;Ostorero et al 2016, Moss et al, in prep. ).…”

NH‐NHI correlation in gigahertz‐peaked‐spectrum galaxies

“…Their radio emission is dominated by the mini-lobes, fully contained in the host galaxy interstellar medium. Although they are increasingly detected in the X-ray domain (O'Dea et al 2000;Risaliti et al 2003;Guainazzi et al 2004Guainazzi et al , 2006Vink et al 2006;Siemiginowska et al 2008;Tengstrand et al 2009), the best angular resolution currently available (∼1 ′′ with Chandra) is not sufficient to resolve the X-ray morphology of most GPS/CSOs. Therefore, the origin of their X-ray emission is still matter of debate (e.g., Siemiginowska et al 2009;Migliori 2015).…”

X‐ray emission from GPS and CSS sources

“…Detections are plotted with the solid red curve and upper limits with the dashed blue curve. The observed columns in GPS quasars reported by Siemiginowska et al (2008) are marked by a big arrow and all are below N H < 10 21 atoms cm −2 .…”

“…During the last decade there have been several efforts to increase the number of X-ray detections. Guainazzi et al (2004Guainazzi et al ( , 2006 and Vink et al (2006) present X-ray samples of GPS galaxies, Siemiginowska et al ( , 2005Siemiginowska et al ( , 2008) discuss X-ray emission in GPS/CSS quasars. Worrall et al(2004) and O'Dea et al (2006) study details of the X-ray emission in a single GPS source.…”

“…5 ′′ scale corresponding to size < 10 kpc and > 40 kpc is marked by arrows. The data points are from Guainazzi et al (2004Guainazzi et al ( , 2006, Vink et al (2006) and Siemiginowska et al (2008).…”