Query : 2021A&A...654A..79G

2021A&A...654A..79G - Astronomy and Astrophysics, volume 654A, 79-79 (2021/10-1)

Quasar clustering at redshift 6.


Abstract (from CDS):

Context. Large-scale surveys over the last years have revealed about 300 quasi-stellar objects (QSOs) at redshifts above 6. Follow-up observations have identified surprising properties, such as the very high black hole (BH) masses, spatial correlations with surrounding cold gas of the host galaxy, and high CIV-MgIIVelocity shifts. In particular, the discovery of luminous high-redshift quasars suggests that at least some BHs likely have high masses at birth and grow efficiently.
Aims. Our aim is to quantify quasar pairs at high redshift for a large sample of objects. This provides a new key constraint on a combination of parameters related to the origin and assembly for the most massive BHs: formation efficiency and clustering, growth efficiency, and the relative contribution of BH mergers.
Methods. We observed 116 spectroscopically confirmed QSOs around redshift 6 with the simultaneous seven-channel imager Gamma-ray Burst Optical/Near-infrared Detector in order to search for companions. Applying colour-colour cuts identical to those which led to the spectroscopically confirmed QSOs, we performed Le PHARE fits to the 26 best QSO pair candidates, and obtained spectroscopic observations for 11 of them.
Results. We do not find any QSO pair with a companion brighter than M1450(AB) < -26 mag within our 0.1-3.3 h–1 cMpc search radius, in contrast to the serendipitous findings in the redshift range 4-5. However, a small fraction of such pairs at this luminosity and redshift is consistent with indications from present-day cosmological-scale galaxy evolution models. In turn, the incidence of L- and T-type brown dwarfs, which occupy a similar colour space to z∼6 QSOs, is higher than expected, by a factor of 5 and 20, respectively.

Abstract Copyright: © J. Greiner et al. 2021

Journal keyword(s): early Universe - galaxies: active - quasars: general - stars: low-mass - brown dwarfs

Status at CDS : Large table(s) will be appraised for possible ingestion in VizieR.

Simbad objects: 3

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Number of rows : 3
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 DES J0454-4448 QSO 04 54 01.79 -44 48 31.1           ~ 16 0
2 BD+52 913 WD* 05 05 30.6180977592 +52 49 51.919301604 10.25 11.44 11.69 11.93 12.108 DA.8 1065 0
3 CD-30 17706 WD* 20 10 56.8486912016 -30 13 06.627142663 11.654 12.286 12.242 12.311 12.381 DA3.1 241 0

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