TY - JOUR
T1 - Galaxy And Mass Assembly (GAMA): colour- and luminosity-dependent clustering from calibrated photometric redshifts
AU - Christodoulou, L
AU - Eminian, C
AU - Loveday, J
AU - Norberg, Peder
AU - Baldry, Ivan K
AU - Hurley, P D
AU - Driver, Simon P
AU - Bamford, Steven P
AU - Hopkins, Andrew Mark
AU - Liske, J
AU - Peacock, John A
AU - Bland-Hawthorn, Jonathan
AU - Brough, Sarah
AU - Cameron, Ewan
AU - Conselice, Christopher J
AU - Croom, Scott Martin
AU - Frenk, C S
AU - Gunawardhana, Madusha
AU - Jones, David Heath
AU - Kelvin, L
AU - Kuijken, K
AU - Nichol, Robert C
AU - Parkinson, H
AU - Pimbblet, Kevin Alan
AU - Popescu, Cristina
AU - Prescott, Matthew
AU - Robotham, A S G
AU - Sharp, Rob
AU - Sutherland, W J
AU - Taylor, Edward
AU - Thomas, D
AU - Tuffs, R
AU - van Kampen, E
AU - Wijesinghe, Dinuka
PY - 2012
Y1 - 2012
N2 - We measure the two-point angular correlation function of a sample of 4289 223 galaxies with r <19.4 mag from the Sloan Digital Sky Survey (SDSS) as a function of photometric redshift, absolute magnitude and colour down to Mr - 5 log h = -14 mag. Photometric redshifts are estimated from ugriz model magnitudes and two Petrosian radii using the artificial neural network package annz, taking advantage of the Galaxy And Mass Assembly (GAMA) spectroscopic sample as our training set. These photometric redshifts are then used to determine absolute magnitudes and colours. For all our samples, we estimate the underlying redshift and absolute magnitude distributions using Monte Carlo resampling. These redshift distributions are used in Limber s equation to obtain spatial correlation function parameters from power-law fits to the angular correlation function. We confirm an increase in clustering strength for sub-L* red galaxies compared with similar to L* red galaxies at small scales in all redshift bins, whereas for the blue population the correlation length is almost independent of luminosity for similar to L* galaxies and fainter. A linear relation between relative bias and log luminosity is found to hold down to luminosities L similar to 0.03L*. We find that the redshift dependence of the bias of the L* population can be described by the passive evolution model of Tegmark Peebles. A visual inspection of a random sample from our r <19.4 sample of SDSS galaxies reveals that about 10 per cent are spurious, with a higher contamination rate towards very faint absolute magnitudes due to over-deblended nearby galaxies. We correct for this contamination in our clustering analysis.
AB - We measure the two-point angular correlation function of a sample of 4289 223 galaxies with r <19.4 mag from the Sloan Digital Sky Survey (SDSS) as a function of photometric redshift, absolute magnitude and colour down to Mr - 5 log h = -14 mag. Photometric redshifts are estimated from ugriz model magnitudes and two Petrosian radii using the artificial neural network package annz, taking advantage of the Galaxy And Mass Assembly (GAMA) spectroscopic sample as our training set. These photometric redshifts are then used to determine absolute magnitudes and colours. For all our samples, we estimate the underlying redshift and absolute magnitude distributions using Monte Carlo resampling. These redshift distributions are used in Limber s equation to obtain spatial correlation function parameters from power-law fits to the angular correlation function. We confirm an increase in clustering strength for sub-L* red galaxies compared with similar to L* red galaxies at small scales in all redshift bins, whereas for the blue population the correlation length is almost independent of luminosity for similar to L* galaxies and fainter. A linear relation between relative bias and log luminosity is found to hold down to luminosities L similar to 0.03L*. We find that the redshift dependence of the bias of the L* population can be described by the passive evolution model of Tegmark Peebles. A visual inspection of a random sample from our r <19.4 sample of SDSS galaxies reveals that about 10 per cent are spurious, with a higher contamination rate towards very faint absolute magnitudes due to over-deblended nearby galaxies. We correct for this contamination in our clustering analysis.
UR - http://onlinelibrary.wiley.com.ezproxy.lib.monash.edu.au/doi/10.1111/j.1365-2966.2012.21434.x/pdf
U2 - 10.1111/j.1365-2966.2012.21434.x
DO - 10.1111/j.1365-2966.2012.21434.x
M3 - Article
SN - 0035-8711
VL - 425
SP - 1527
EP - 1548
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -