Portal de Periódicos da CAPES

A striking relationship between dust extinction and radio detection in DESI QSOs: evidence for a dusty blow-out phase in red QSOs

2023; Oxford University Press; Volume: 525; Issue: 4 Linguagem: Inglês

10.1093/mnras/stad2603

1365-2966

V. A. Fawcett, D. M. Alexander, A. Brodzeller, A. C. Edge, D. J. Rosario, Adam D. Myers, J. Aguilar, S. P. Ahlen, R. Alfarsy, D. Brooks, Rebecca Canning, Chiara Circosta, Kyle Dawson, Axel de la Macorra, Peter Doel, Kevin Fanning, Andreu Font-Ribera, Jaime E. Forero-Romero, Satya Gontcho A Gontcho, J. Guy, C. M. Harrison, K. Honscheid, S. Juneau, R. Kehoe, Theodore Kisner, Anthony Kremin, Martin Landriau, Marc Manera, Aaron M. Meisner, R. Miquel, John Moustakas, Jundan Nie, Will J. Percival, C. Poppett, Ragadeepika Pucha, Graziano Rossi, David J. Schlegel, M. Siudek, G. Tarlé, B. A. Weaver, Zhiming Zhou, Hu Zou,

Stellar, planetary, and galactic studies

ABSTRACT We present the first eight months of data from our secondary target programme within the ongoing Dark Energy Spectroscopic Instrument (DESI) survey. Our programme uses a mid-infrared and optical colour selection to preferentially target dust-reddened quasi-stellar objects (QSOs) that would have otherwise been missed by the nominal DESI QSO selection. So far, we have obtained optical spectra for 3038 candidates, of which ∼70 per cent of the high-quality objects (those with robust redshifts) are visually confirmed to be Type 1 QSOs, consistent with the expected fraction from the main DESI QSO survey. By fitting a dust-reddened blue QSO composite to the QSO spectra, we find they are well-fitted by a normal QSO with up to AV ∼ 4 mag of line-of-sight dust extinction. Utilizing radio data from the LOFAR Two-metre Sky Survey (LoTSS) DR2, we identify a striking positive relationship between the amount of line-of-sight dust extinction towards a QSO and the radio detection fraction, that is not driven by radio-loud systems, redshift and/or luminosity effects. This demonstrates an intrinsic connection between dust reddening and the production of radio emission in QSOs, whereby the radio emission is most likely due to low-powered jets or winds/outflows causing shocks in a dusty environment. On the basis of this evidence, we suggest that red QSOs may represent a transitional ‘blow-out’ phase in the evolution of QSOs, where winds and outflows evacuate the dust and gas to reveal an unobscured blue QSO.