gravitational lensing: strong; galaxies: active; quasars: general; galaxies: individual: SDSS J1004+4112; galaxies: individual: PG 1115+080; galaxies: star formation; Astrophysics - Astrophysics of Galaxies; Astrophysics - High Energy Astrophysical Phenomena
Abstract :
[en] The radio quasar luminosity function exhibits an upturn around $L_{6\rm \:GHz}=10^{23}$ W Hz[SUP]-1[/SUP] that is well-modelled by a star-forming host galaxy population. This distribution leads some authors to cite star formation as the main radio emission mechanism in so-called radio-quiet quasars (RQQs). Understanding the origin of RQQ radio emission is crucial for our understanding of quasar feedback mechanisms - responsible for the regulation of star formation in the host galaxy - and for understanding galaxy evolution as a whole. By observing RQQs that have been magnified by strong gravitational lensing, we have direct access to the RQQ population out to cosmic noon, where evidence for twin mini-jets has recently been found in a sub-µJy RQQ. Here we present radio observations of two lensed RQQs using the VLA at 5 GHz, the latest objects to be observed in a sample of quadruply-imaged RQQs above -30°. In SDSS J1004+4112 we find strong evidence for AGN-related radio emission in the variability of the source. In PG 1115+080 we find tentative evidence for AGN-related emission, determined by comparing the radio luminosity with modelled dust components. If confirmed in the case of PG 1115+080, which lies on the radio-FIR correlation, the result would reinforce the need for caution when applying the correlation to rule out jet activity and when assuming no AGN heating of FIR-emitting dust when calculating star formation rates. Our programme so far has shown that the two of the faintest radio sources ever imaged show strong evidence for AGN-dominated radio emission.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Hartley, P.; SKA Observatory, Jodrell Bank, Lower Withington, Macclesfield, M13 9PL Cheshire, UK ; Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, M13 9PL Manchester, UK
Jackson, N.; Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, M13 9PL Manchester, UK
Badole, S.; Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, M13 9PL Manchester, UK
McKean, J. P.; ASTRON, Netherlands Institute for Radio Astronomy, Oude Hoogeveensedijk 4, NL-7991 PD Dwingeloo, the Netherlands ; Kapteyn Astronomical Institute, University of Groningen, PO Box 800, NL-9700AV Groningen, the Netherlands
Sluse, Dominique ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa)
Vives-Arias, H.; Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir km. 4, Torrejón de Ardoz, E-28850 Madrid, Spain)
Language :
English
Title :
Using strong lensing to understand the microJy radio emission in two radio quiet quasars at redshift 1.7