J/MNRAS/442/946 z~5.7 C IV absorption systems (Diaz+, 2014) ================================================================================ Large-scale environment of z~5.7 C IV absorption systems. I. Projected distribution of galaxies. Diaz C.G., Koyama Y., Ryan-Weber E.V., Cooke J., Ouchi M., Shimasaku K., Nakata F. =2014MNRAS.442..946D ================================================================================ ADC_Keywords: Galaxies, photometry Keywords: galaxies: distances and redshifts - galaxies: high-redshift - intergalactic medium - early Universe Abstract: Metal absorption systems are products of star formation. They are believed to be associated with massive star-forming galaxies, which have significantly enriched their surroundings. To test this idea with high column density CIV absorption systems at z~5.7, we study the projected distribution of galaxies and characterize the environment of CIV systems in two independent quasar lines of sight: J103027.01+052455.0 and J113717.73+354956.9. Using wide-field photometry (~80x60h^-1^ comoving Mpc), we select bright (M_UV(1350{AA})_<~-21.0mag) Lyman break galaxies (LBGs) at z~5.7 in a redshift slice {Delta}z~0.2 and we compare their projected distribution with z~5.7 narrow-band selected Lyman alpha emitters (LAEs, {Delta}z~0.08). We find that the CIV systems are located more than 10h^-1^ projected comoving Mpc from the main concentrations of LBGs and no candidate is closer than ~5h^-1^ projected comoving Mpc. In contrast, an excess of LAEs - lower mass galaxies - is found on scales of ~10h^-1^ comoving Mpc, suggesting that LAEs are the primary candidates for the source of the CIV systems. Furthermore, the closest object to the system in the field J1030+0524 is a faint LAE at a projected distance of 212h^-1^ physical kpc. However, this work cannot rule out undiscovered lower mass galaxies as the origin of these absorption systems. We conclude that, in contrast with lower redshift examples (z<~3.5), strong CIV absorption systems at z~5.7 trace low-to-intermediate density environments dominated by low-mass galaxies. Moreover, the excess of LAEs associated with high levels of ionizing flux agrees with the idea that faint galaxies dominate the ionizing photon budget at this redshift. Description: This work is based on broad-band and narrow-band photometry obtained with Suprime-Cam on the Subaru Telescope. We use broad-band Rc, i' and z' filters covering the wavelength range ~5800-10000{AA} and a custom-made NB filter to detect Ly{alpha} in emission at redshift z=5.71+/-0.04 (NBC IV, {lambda}c=8162{AA}, FWHM=100{AA}). Observations with the NBC IV, Rc and i' bands were acquired on the nights of 2011 March 07-08 and images in the z' band were obtained on 2011 March 31 and April 01. We observed two fields centred on QSOs SDSS J103027.01+052455.0 (z_em_=6.309, RA=10:30:27.01, DE=05:24:55.0), SDSS J113717.73+354956.9 (z_em_=6.01, RA=11:37:17.73, DE=35:49:56.9) (Fan et al., 2006AJ....132..117F), hereafter J1030+0524 and J1137+3549. Objects: ------------------------------------------------------------------------ RA (ICRS) DE Designation(s) ------------------------------------------------------------------------ 10 30 27.01 +05 24 55.0 SDSS J103027.01+052455.0 = QSO J1030+0524 11 37 17.73 +35 49 56.9 SDSS J113717.73+354956.9 = QSO J1137+3549 ------------------------------------------------------------------------ File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file tablee1.dat 97 33 z~5.7 Lyman break galaxies (LBGs) in J1030+0524 field tablee2.dat 97 61 z~5.7 Lyman break galaxies (LBGs) in J1137+3549 field tablee3.dat 97 23 z~6.0 i'-dropouts in J1030+0524 field tablee4.dat 97 56 z~6.0 i'-dropouts in J1137+3549 field tablee5.dat 97 45 z~5.7 Lyman alpha emitters (LAEs) in J1030+0524 field tablee6.dat 97 15 z~5.7 Lyman alpha emitters (LAEs) in J1137+3549 field -------------------------------------------------------------------------------- See also: J/PASJ/57/165 : Ly{alpha} emitters in SUBARU Deep Field (Taniguchi+, 2005) J/ApJ/648/7 : Ly{alpha} emitters at z=6.5 in Subaru Deep Field (Kashikawa+, 2006) J/ApJ/693/507 : Stars of Lyman break galaxies at z~5 (Yabe+, 2009) J/ApJ/760/128 : Ly{alpha} emission from 4 ] Limit flag on Rcmag 27- 31 F5.2 mag Rcmag Cousins R magnitude in 2" or 2.4" aperture (1) 33- 36 F4.2 mag e_Rcmag ? rms uncertainty on Rcmag 38- 39 A2 --- l_i'mag [~> ] Limit flag on imag 40- 44 F5.2 mag i'mag i' magnitude (2"or 2.4" aperture radius) (1) 46- 49 F4.2 mag e_i'mag ? rms uncertainty on imag 51- 52 A2 --- l_z'mag [~> ] Limit flag on z'mag 53- 57 F5.2 mag z'mag z' magnitude (2"or 2.4" aperture radius) (1) 59- 62 F4.2 mag e_z'mag ? rms uncertainty on z'mag 64- 65 A2 --- l_NBCiv [~> ] Limit flag on NBCiv 66- 70 F5.2 mag NBCiv Magnitude in narrow-band NBCiv filter (8162{AA}) magnitude (2" or 2.4" aperture radius) (1) 72- 75 F4.2 mag e_NBCiv ? rms uncertainty on NBCiv 77- 81 F5.2 mag z'maga z' magnitude (MAG_AUTO) 83- 86 F4.2 mag e_z'maga rms uncertainty on z'mag 88- 92 F5.3 pix rhl Half-light radius (1pix=0.2arcsec) 94- 97 F4.2 --- S/G [0/1] Stellarity index in z'-band (0=galaxy, 1=star) -------------------------------------------------------------------------------- Note (1): aperture radius = 2" for J1030+0524 field (tablee1, tablee3 and tablee5) aperture radius = 2.4" for J1137+3549 field (tablee2, tablee4 and tablee6) NBCiv = custom-made narrow-band filter to detect Ly{alpha} in emission at redshift z=5.71+/-0.04: {lambda}_c_=8162{AA}, FWHM=100{AA} -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Patricia Vannier [CDS] 03-Mar-2015