학술논문
A striking relationship between dust extinction and radio detection in DESI QSOs: evidence for a dusty blow-out phase in red QSOs
Document Type
Working Paper
Author
Fawcett, V. A.; Alexander, D. M.; Brodzeller, A.; Edge, A. C.; Rosario, D. J.; Myers, A. D.; Aguilar, J.; Ahlen, S.; Alfarsy, R.; Brooks, D.; Canning, R.; Circosta, C.; Dawson, K.; de la Macorra, A.; Doel, P.; Fanning, K.; Font-Ribera, A.; Forero-Romero, J. E.; Gontcho, S. Gontcho A; Guy, J.; Harrison, C. M.; Honscheid, K.; Juneau, S.; Kehoe, R.; Kisner, T.; Kremin, A.; Landriau, M.; Manera, M.; Meisner, A. M.; Miquel, R.; Moustakas, J.; Nie, J.; Percival, W. J.; Poppett, C.; Pucha, R.; Rossi, G.; Schlegel, D.; Siudek, M.; Tarlé, G.; Weaver, B. A.; Zhou, Z.; Zou, H.
Source
Subject
Language
Abstract
We present the first eight months of data from our secondary target program within the ongoing Dark Energy Spectroscopic Instrument (DESI) survey. Our program uses a mid-infrared and optical colour selection to preferentially target dust-reddened 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% 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.
Comment: 21 pages, 17 figures, 6 tables, accepted by MNRAS
Comment: 21 pages, 17 figures, 6 tables, accepted by MNRAS