Witnessing the transformation of a quasar host galaxy at z=1.6

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Humphrey, A (Author) Other; Roche, N (Author) Other; Gomes, JM (Author) Other; Papaderos, P (Author) Other; Villar Martin, M (Author) Other; Mercedes E Filho (Author) FEUP; Emonts, BHC (Author) Other; Aretxaga, I (Author) Other; Binette, L (Author) Other; Flaquer, BO (Author) Other; Lagos, P (Author) Other; Torrealba, J (Author) Other

Journal

Title: Monthly Notices of the Royal Astronomical Society

Vol. 447

Pages: 3322-3327

ISSN: 0035-8711

Publisher: Oxford University Press

Indexing

ISI Web of Knowledge - 4 Citations

Scopus - 4 Citations

Other information

Authenticus ID: P-00G-27B

DOI: 10.1093/mnras/stu2510

Abstract (EN): A significant minority of high-redshift radio galaxy (HzRG) candidates show extremely red broad-band colours and remain undetected in emission lines after optical 'discovery' spectroscopy. In this paper, we present deep GTC optical imaging and spectroscopy of one such radio galaxy, 5C 7.245, with the aim of better understanding the nature of these enigmatic objects. Our g-band image shows no significant emission coincident with the stellar emission of the host galaxy, but does reveal faint emission offset by similar to 3 arcsec (26 kpc) therefrom along a similar position angle to that of the radio jets, reminiscent of the 'alignment effect' often seen in the optically luminous HzRGs. This offset g-band source is also detected in several UV emission lines, giving it a redshift of 1.609, with emission line flux ratios inconsistent with photoionization by young stars or an AGN, but consistent with ionization by fast shocks. Based on its unusual gas geometry, we argue that in 5C 7.245 we are witnessing a rare (or rarely observed) phase in the evolution of quasar hosts when stellar mass assembly, accretion on to the back hole, and powerful feedback activity has eradicated its cold gas from the central similar to 20 kpc, but is still in the process of cleansing cold gas from its extended halo.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6