X-Ray

Far -Infrared

Images, Maps, Spectra and SEDs

PKS0023-26

Spitzer IRS spectra, strong starburst tracing PAH features can be seen in this mid-infrared spectrum.

Dicken et al. (in preperation)

N

E

0.322

00 25 49.18

-26 02 12.8

NLRG

CSS

-

Notes

    This powerful (log P5 GHz= 27.33 W Hz−1), compact steep spectrum radio source (D = 2.9 kpc: Tzioumis et al. 2002), is identified with an mv= 19.5 galaxy (Prestage & Peacock 1983; Wall & Peacock 1985). The double lobed radio source has a maximum size of ∼680 mas (∼4.25 kpc), aligned along PA −34° (Tzioumis et al. 2002). Spectroscopically it is classified as an NLRG and its emission-line spectrum has intermediate ionization with relatively strong [OII]λ3727 and [NI]λ5199 emission (Tadhunter et al. 1993; Morganti et al. 1997). The optical continuum displays a large UV excess with low UV polarization (P_UV < 2.0 per cent) and no sign of broad permitted lines.  Details of the kinematics and ionization of the emission line gas in this source are discussed in Holt et al. (2008, MNRAS, 387, 639) and Holt et al. (2009, MNRAS, 400, 589) respectively.

    The host galaxy of PKS0023-26 shares a common envelope with two early-type galaxies at projected distances of 5.8 arcsec (26 kpc) to the NE (C1) and 6.9 arcsec (31 kpc) to the SW (C2). Analysis of our VLT/FORS spectrum along PA51 demonstrates that the companion galaxies have a similar redshift to PKS0023-26 (z_nuc = 0.321955 ± 0.000014), as does a further early-type galaxy 25.8 arcsec (116 kpc) to the NW (C3), which falls within the slit for our PA145 VLT/FORS1 spectra. Based on measurements of the detected Hβ absorption features, the redshifts of C1, C2 and C3 are z_C1 = 0.32499 ± 0.00015, z_C2 = 0.32282 ± 0.00033 and z_C3 = 0.32318 ± 0.00028, corresponding to velocity shifts relative to the rest frame of the nucleus of PKS0023- 26 of +690 ± 34, +200 ± 75 and +280 ± 60 km s−1, respectively. In fact, the field shows several early-type galaxies close (in projection) to PKS0023-26, suggesting that it lies at the heart of a rich cluster of galaxies. However, perhaps the most interesting feature of the image is the extraordinary amorphous structure that lies between PKS0023-26 and its two closest companions. This appears to be crossed by dust lanes, and may comprise regions of active star formation within the extended halo of the galaxy. Although the halo structure is too faint to study in detail with our existing spectroscopic observations, our deep spectrum of the brighter core of the galaxy reveals a YSP with a relatively young age (<0.05 Gyr: Holt et al. 2007). The presence of significant star formation activity in PKS0023-26 has also been confirmed by Dicken et al. (2009, 2011) using the identification of strong PAH features, infrared excess and cool mid- to far-infrared colours.

Gemini/GMOS-S: median filtered image

4996 MHz, Merlin radio map