The clustering of z > 7 galaxies: predictions from the BLUETIDES simulation. Issue 4 (6th December 2017)

• Record Type: Journal Article
• Authors: Bhowmick, Aklant K; Di Matteo, Tiziana; Feng, Yu; Lanusse, Francois
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 474:Issue 4(2018)
• Page Start: 5393
• Page End: 5405
• Publication Date: 2017-12-06
• Subjects: galaxies: evolution -- galaxies: formation -- galaxies: haloes -- galaxies: high-redshift -- galaxies: statistics -- large-scale structure of Universe; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stx3149
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: We study the clustering of the highest z galaxies (from ∼0.1 to a few tens Mpc scales) using the BLUETIDES simulation and compare it to current observational constraints from Hubble legacy and Hyper Suprime Cam (HSC) fields (at z = 6–7.2). With a box length of 400 Mpc h −1 on each side and 0.7 trillion particles, BLUETIDES is the largest volume high-resolution cosmological hydrodynamic simulation to date ideally suited for studies of high- z galaxies. We find that galaxies with magnitude m UV < 27.7 have a bias ( b g ) of 8.1 ± 1.2 at z = 8, and typical halo masses M H ≳ 6 × 10 10 M⊙ . Given the redshift evolution between z = 8 and z = 10 [ b g ∝ (1 + z ) 1.6 ], our inferred values of the bias and halo masses are consistent with measured angular clustering at z ∼ 6.8 from these brighter samples. The bias of fainter galaxies (in the Hubble legacy field at H 160 ≲ 29.5) is 5.9 ± 0.9 at z = 8 corresponding to halo masses M H ≳ 10 10 M⊙ . We investigate directly the 1-halo term in the clustering and show that it dominates on scales r ≲ 0.1 Mpc h −1 (Θ ≲ 3 arcsec) with non-linear effect at transition scales between the one-halo and two-halo term affecting scales 0.1 Mpc h −1 ≲ r ≲ 20 Mpc h −1 (3 arcsec ≲ Θ ≲ 90 arcsec). Current clustering measurements probe down to the scales in the transition between one-halo and two-halo regime where non-linear effects are important. The amplitude of the one-halo term implies that occupation numbers for satellites in BLUETIDES are somewhat higher than standard halo occupation distributions adopted in these analyses (which predict amplitudes in the one-halo regime suppressed by a factor 2–3). That possibly implies a higher number of galaxies detected by JWST (at small scales and even fainter magnitudes) observing these fields.