The [CII] and FIR properties of z > 6 radio-loud quasars

Abstract

There are only five radio-loud quasars currently known within 1 Gyr from the Big Bang (z > 6) and the properties of their host galaxies have not been explored in detail. We present a NOrthern Extended Millimeter Array (NOEMA) survey of [CII] (158 μm) and underlying continuum emission of four z > 6 radio-loud quasars, revealing their diverse properties. J0309+2717 (z = 6.10) has a bright [CII] line and underlying continuum, implying that the host galaxy is a starburst with a star-formation rate SFR = 340–1200 M⊙ yr−1. J1429+5447 (z = 6.18) has a SFR = 520 − 870 M⊙ yr−1 and its [CII] profile is consistent with two Gaussians, which could be interpreted as a galaxy merger. J1427+3312 (z = 6.12) has a moderate SFR = 30–90 M⊙ yr−1. Notably, this is a broad absorption line quasar and we searched for the presence of high-velocity outflows in the host galaxy. Although the NOEMA data tentatively reveal a broad component of the [CII] line as wide as ∼1400 km s−1, the sensitivity of our current data are not sufficient to confirm it. Finally, P172+18 (z = 6.82) is undetected in both [CII] and the continuum, implying a SFR < 22–40 M⊙ yr−1. The broad range of SFRs is similar to what is observed in radio-quiet quasars at similar redshifts. If radio jets do not significantly contribute to both [CII] and IR luminosities, this suggests there is no feedback from the jet on the star formation in the host galaxy.

The X–shooter/ALMA Sample of Quasars in the Epoch of Reionization. II. Black Hole Masses, Eddington Ratios, and the Formation of the First Quasars

“…In Figure 11, we further reinforce these findings by complementing their results with all available estimates of dynamical masses of z  5.7 hosts from the literature (Willott et al 2015(Willott et al , 2017Izumi et al 2018Izumi et al , 2019Izumi et al , 2021Pensabene et al 2020). For unresolved observations (Willott et al 2013;Mazzucchelli et al 2017;Decarli et al 2018;Yang et al 2019b;Eilers et al 2020;Andika et al 2020;Wang et al 2021a;Khusanova et al 2022), we additionally include estimates of the host galaxy masses by using the relations between M Dyn and FWHM and size of the [C II] 158 μm emitting region (where published) provided by Neeleman et al (2021).…”

“…Indeed, given the extreme brightness of the quasar emission at these wavelengths, the detection of the stellar component has proven to be prohibitive with large aperture ground-based telescopes (e.g., Targett et al 2012) and even with HST (e.g., Mechtley et al 2012;Marshall et al 2020a). On the other hand, the interstellar medium (ISM) of tens of quasar host galaxies has been detected at millimeter-wavelengths in the dust continuum and in the [C II] 158 μm emission line (e.g., Wang et al 2016bWang et al , 2019cDecarli et al 2017Decarli et al , 2018Venemans et al 2018;Wang et al 2019a;Rojas-Ruiz et al 2021;Khusanova et al 2022) and, in some cases, also in the [O III] 88 μm, [O I] 146 μm, [C I] 369 μm, CO, and water lines (e.g., Wang et al 2011aWang et al , 2011bWang et al , 2016bVenemans et al 2017a;Walter et al 2018;Novak et al 2019;Shao et al 2019;Yang et al 2019b;Wang et al 2019a;Pensabene et al 2021;Decarli et al 2022;Li et al 2022;Meyer et al 2022a;Pensabene et al 2022). In particular, Atacama Large Millimeter/submillimeter Array (ALMA) [C II] 158 μm observations at a resolution of 1 kpc are providing detailed information on star formation rates, the presence of molecular outflows, dynamical masses, and morphology of early massive galaxies hosting SMBHs (Venemans et al 2019(Venemans et al , 2020Novak et al 2020;Neeleman et al 2021;Walter et al 2022).…”

Discovery of 24 radio-bright quasars at 4.9 ≤ z ≤ 6.6 using low-frequency radio observations

“…To further study the AGN and host galaxy properties of these new high-z quasars, additional observations are necessary (see e.g. Khusanova et al 2022). The SMBH masses and broad line regions for example can be constrained by measuring the Civ and Mgii NIR lines (see e.g.…”

“…Wang et al 2013;Venemans et al 2016;Izumi et al 2019), however the fraction of extinguished quasar radiation caused by dust and whether this represents an evolutionary stage in a quasar's lifetime is still unknown. Furthermore, the FIR and millimetre emission of radio-loud quasars is likely not only caused by cold dust but also by synchrotron emission (Rojas-Ruiz et al 2021;Khusanova et al 2022).…”

The Pan-STARRS1 z > 5.6 Quasar Survey. II. Discovery of 55 Quasars at 5.6 < z < 6.5

“…The observations were carried out on 2021 December 13 with an on-source time of 7.5 hr. We reduced the data with GILDAS, 19 following the steps described in Khusanova et al (2022). We used 3C84 and LKHA101 as bandpass and flux density calibrators, respectively.…”