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24433bb · Jun 28, 2018

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dmu24_GAMA-15

GAMA 15 Photometric Redshifts - V1 (20180210)

GAMA15/master_catalogue_gama-15_20180119_photoz_20180210_r_optimised.fits

Key information

Masterlist used:

dmu1/dmu1_ml_GAMA-15/data/master_catalogue_gama-15_20180119.fits

Spectroscopic redshift sample used:

dmu23/dmu23_GAMA-15/data/GAMA15-specz-v2_1-PRIVATE.csv

Templates used:

  • EAZY Default
  • Atlas of Galaxy SEDs (Brown et al. 2014)
  • XMM-COSMOS Template library

Filters used:

Telescope / Instrument Filter Available Used
Subaru/HSC suprime_g Yes Yes
Subaru/HSC suprime_r Yes Yes
Subaru/HSC suprime_i Yes Yes
Subaru/HSC suprime_z Yes Yes
Subaru/HSC suprime_y Yes Yes
VST/OmegaCam omegacam_u Yes Yes
VST/OmegaCam omegacam_g Yes Yes
VST/OmegaCam omegacam_r Yes Yes
VST/OmegaCam omegacam_i Yes Yes
CTIO/DECam decam_g Yes No
CTIO/DECam decam_r Yes No
CTIO/DECam decam_z Yes No
Pan-STARRS1/Pan-STARRS1 gpc1_g Yes No
Pan-STARRS1/Pan-STARRS1 gpc1_r Yes No
Pan-STARRS1/Pan-STARRS1 gpc1_i Yes No
Pan-STARRS1/Pan-STARRS1 gpc1_z Yes No
Pan-STARRS1/Pan-STARRS1 gpc1_y Yes No
UKIRT/WFCAM ukidss_j Yes Yes
UKIRT/WFCAM ukidss_h Yes Yes
UKIRT/WFCAM ukidss_k Yes Yes
VISTA/VIRCAM vircam_z Yes Yes
VISTA/VIRCAM vircam_y Yes Yes
VISTA/VIRCAM vircam_j Yes Yes
VISTA/VIRCAM vircam_h Yes Yes
VISTA/VIRCAM vircam_k Yes Yes

Additional Machine Learning Estimates

For the main galaxy population, three additional Gaussian Process machine learning estimates were also incorporated into the Bayesian combination estimates. These were training using the combined spectroscopic sample of all three GAMA fields - with cost-sensitive learning weights calibrated for each specific field. The three sets of filters used were:

  • OmegaCam u,g,r,i
  • HyperSuprimeCam g,r,i,z,y
  • OmegaCam g,r,i + VISTA/VIRCAM J and Ks

For the AGN subset, one GP estimate was also included resulting in much better performance. This estimate used the following filters:

  • OmegaCam u,g,r,i + VISTA/VIRCAM J

Additional selections applied:

  • In order to have a fully calibrated redshift estimate, sources must have a magnitude measurement in either any of the optical r-bands.
  • Sources must also be detected in 4 bands at different wavelengths for a redshift to have been estimated (i.e. multiple r-band detections count only as one). Multiple detections in similar optical bands do not count due to the issues described below.

Field-specific issues encountered:

Initial runs including PanSTARRS and DECam observations resulted in significantly poorer results than expected given the excellent KIDS and HSC photometry available in the field. As these two datasets were found to be the main causes of the issues when used in combination with the other datasets, they were excluded resulting in excellent overall quality. Due to the

Plots for diagnostics and quality checking

Chi2 Distributions

Star-Galaxy Chi2 Comparison

Spec-z Comparison

Stats vs z

Stats vs mag

PDF Accuracy Gal

PDF Accuracy AGN