First CO(17-16) emission line detected in a z > 6 quasar
Abstract
We report the serendipitous detection of the CO(17-16) emission line toward the quasar SDSSJ114816.64+525150.3 (J1148) at redshift z = 6.4 obtained with the Plateau de Bure Interferometer. The CO(17-16) line is possibly contaminated by OH+ emission, that may account for ~ 35 - 60% of the total flux observed. Photo-Dissociation and X-ray Dominated Regions (PDRs and XDRs) models show that PDRs alone cannot reproduce the high luminosity of the CO(17-16) line relative to low-J CO transitions and that XDRs are required. By adopting a composite PDR+XDR model we derive molecular cloud and radiation field properties in the nuclear region of J1148. Our results show that highly excited CO lines represent a sensitive and possibly unique tool to infer the presence of X-ray faint or obscured supermassive black hole progenitors in high-z galaxies.
Keywords
Cite
@article{arxiv.1409.4413,
title = {First CO(17-16) emission line detected in a z > 6 quasar},
author = {Simona Gallerani and Andrea Ferrara and Roberto Neri and Roberto Maiolino},
journal= {arXiv preprint arXiv:1409.4413},
year = {2015}
}
Comments
6 pages, 4 figures, accepted for publication in MNRAS Letter