SED Constraints on the Highest-z Blazar Jet: QSO J0906+6930

An, Hongjun; Romani, Roger W.

doi:10.3847/1538-4357/aab435

Cited by 20 publications

(15 citation statements)

References 36 publications

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“…∘ 2. These values are consistent with the parametric fitting of the spectral energy distribution 27 , where δ = 9 -.…”

Section: Doppler Boosting Parameterssupporting

confidence: 88%

“…From the inferred apparent velocity and Doppler factor, the bulk Lorentz factor Γ = 3.6 ± 0.5 and inclination angle towards the observer line of sight θ = 6.º8 ± 2.º2. These values are consistent with estimates from the parametric modeling of the spectral energy distribution 27 . The lower Lorentz factor and slower jet component are consistent with the less powerful nature of the J0906+6930 jet (jet/Eddington luminosity ~ 0.004, see Methods jet and ISM properties).…”

Section: Introductionsupporting

confidence: 88%

“…The relatively less powerful jet, in addition to clues from the radio spectrum and polarisation point to its possible nascent nature. A prominent disk emission is inferred from the modelling of the spectral energy distribution of this and three other high-z blazars 27 . This coupled with a relatively less powerful jet luminosity marks a possible transition in this source between the accretion or quasar mode and the onset of the jet or radio mode.…”

Section: Introductionmentioning

confidence: 74%

“…Based on the location of the synchrotron peak frequency νs in the spectral energy distribution, blazars are classified into low synchrotron peaked if νs < 10 14 Hz (in the infrared), intermediate synchrotron peaked if 10 14 Hz < νs < 10 15 Hz (optical -ultra-violet) and high synchrotron peaked if νs > 10 15 Hz (in the Xrays). J0906+6930 is identified as a low synchrotron peaked blazar with νs ~ 10 12 Hz 27 . Such sources are characterised by energetic jets with relatively highly superluminal (apparent) jet components.…”

Section: Introductionmentioning

confidence: 99%

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Evolving parsec-scale radio structure in the most distant blazar known

Mohan

Zhang

et al. 2020

Nat Commun

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Blazars are a sub-class of quasars with Doppler boosted jets oriented close to the line of sight, and thus efficient probes of supermassive black hole growth and their environment, especially at high redshifts.Here we report on Very Long Baseline Interferometry observations of a blazar J0906+6930 at z = 5.47, which enabled the detection of polarised emission and measurement of jet proper motion at parsec scales. The observations suggest a less powerful jet compared with the general blazar population, including lower proper motion and bulk Lorentz factor. This coupled with a previously inferred high accretion rate indicate a transition from an accretion radiative power to a jet mechanical power based transfer of energy and momentum to the surrounding gas.While alternative scenarios could not be fully ruled out, our results indicate a possibly nascent jet embedded in and interacting with a dense medium resulting in a jet bending.Here, we report the measurement of proper motion and linear polarisation in the parsec-scale jet of this high redshift blazar. We use new 15-GHz data observed with the VLBA in 2017 and 2018, archival VLBA data obtained in 2004-2005 (see details in Supplementary Table 1) and the flux densities reported by the 40 m telescope at the Owens Valley Radio Observatory (OVRO) to explore the evolution of the source morphology and infer its physical characteristics. The jet parameters (lower proper motion and bulk Lorentz factor) are inclined to support a less powerful jet, compared with the general blazar population. The jet interacts with the surrounding interstellar medium resulting in a jet bending and polarised emission.

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“…∘ 2. These values are consistent with the parametric fitting of the spectral energy distribution 27 , where δ = 9 -.…”

Section: Doppler Boosting Parameterssupporting

confidence: 88%

Section: Introductionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evolving parsec-scale radio structure in the most distant blazar known

Mohan

Zhang

et al. 2020

Nat Commun

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show abstract

“…In spite of the different population statistics referenced previously, FS-RQs at high redshift appear to have very similar SEDs to those at lower redshift. For instance, the confirmed highestredshift FSRQ to date, J0906+6930 at z = 5.47, has an observed SED similar to lower-z FSRQs (An & Romani 2018). It is therefore reasonable to suppose that the large suite of lower-redshift FSRQ observations may be used to characterize the radio emission profile of such objects even at higher redshifts.…”

Section: The Radio Emission Of High-z Quasarsmentioning

confidence: 99%

Cosmological test using the high-redshift detection rate of FSRQs with the Square Kilometre Array

Leaf

Melia

2019

Monthly Notices of the Royal Astronomical Society

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We present a phenomenological method for predicting the number of Flat Spectrum Radio Quasars (FSRQs) that should be detected by upcoming Square Kilometer Array (SKA) SKA1-MID Wide Band 1 and Medium-Deep band 2 surveys. We use the Fermi Blazar Sequence and mass estimates of Fermi FSRQs, and γ-ray emitting Narrow Line Seyfert 1 galaxies, to model the radio emission of FSRQs as a function of mass alone, assuming a near-Eddington accretion rate, which is suggested by current quasar surveys at z 6. This is used to determine the smallest visible black hole mass as a function of redshift in two competing cosmologies we compare in this paper: the standard ΛCDM model and the R h = ct universe. We then apply lockstep growth to the observed black-hole mass function at z = 6 in order to devolve that population to higher redshifts and determine the number of FSRQs detectable by the SKA surveys as a function of z. We find that at the redshifts for which this method is most valid, ΛCDM predicts ∼ 30 times more FSRQs than R h = ct for the Wide survey, and ∼ 100 times more in the Medium-Deep survey. These stark differences will allow the SKA surveys to strongly differentiate between these two models, possibly rejecting one in comparison with the other at a high level of confidence.

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A Chandra survey of z ≥ 4.5 quasars

Wang

Yang

et al. 2021

Monthly Notices of the Royal Astronomical Society

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X-ray observations provide a unique probe of the accretion disk corona of supermassive black holes (SMBHs). In this paper, we present a uniform Chandra X-ray data analysis of a sample of 152 z ≥ 4.5 quasars. We firmly detect 46 quasars of this sample in 0.5-2 keV above 3 σ and calculate the upper limits of the X-ray flux of the remaining. We also estimate the power law photon index of the X-ray spectrum of 31 quasars. 24 of our sample quasars are detected in the FIRST or NVSS radio surveys; all of them are radio-loud. We statistically compare the X-ray properties of our z ≥ 4.5 quasars to other X-ray samples of AGN at different redshifts. The relation between the rest-frame X-ray luminosity and other quasar parameters, such as the bolometric luminosity, UV luminosity, or SMBH mass, show large scatters. These large scatters can be attributed to the narrow luminosity range at the highest redshift, the large measurement error based on relatively poor X-ray data, and the inclusion of radio-loud quasars in the sample. The LX − LUV relationship is significantly sub-linear. We do not find a significant redshift evolution of the LX − LUV relation, expressed either in the slope of this relation, or the departure of individual AGNs from the best-fit αOX − LUV relation (ΔαOX). The median value of the X-ray photon index is Γ ≈ 1.79, which does not show redshift evolution from z = 0 to z ∼ 7. The X-ray and UV properties of the most distant quasars could potentially be used as a standard candle to constrain cosmological models. The large scatter of our sample on the Hubble diagram highlights the importance of future large unbiased deep X-ray and radio surveys in using quasars in cosmological studies.

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SED Constraints on the Highest-z Blazar Jet: QSO J0906+6930

Cited by 20 publications

References 36 publications

Evolving parsec-scale radio structure in the most distant blazar known

Evolving parsec-scale radio structure in the most distant blazar known

Cosmological test using the high-redshift detection rate of FSRQs with the Square Kilometre Array

A Chandra survey of z ≥ 4.5 quasars

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