LOFAR Meeting - Bologna, Sept 2016
Leiden Observatory
Close collaboration with HELP (Herschel Extragalactic Legacy Project - PI S. Oliver)
Collecting and matching all publicly available imaging
Will include photometric redshifts and multi-wavelength physical modelling for all Herschel fields
PanSTARRS optical (grizy)
UKIRT Hemisphere near-IR (J)
WISE mid-IR (3.4um/4.5um)
PanSTARRs 3pi survey coverage
DECALS: -20° < δ < +30°
HyperSuprimeCam Survey
Brammer et al. (2008)
Arnouts et al. (1999)
Ilbert et al. (2006)
Bender et al. (2001)
Bolzonella et al. (2000)
Feldmann et al. (2006)
Benitez (2000)
Total citations: ~2800
Additional rest-frame errors
Corrections to the observed zeropoints
Brammer et al. (2008)
Dust
AGB Stars?
PAH/Dust emission/AGN?
Brammer et al. (2008)
Benitez (2000)
(aka machine learning)
Euclid: ~1.5 billion galaxies
LSST: ~10 billion galaxies
Estimated time to run EAZY on all sources (on a desktop machine):
~2+ years (Euclid)
~14+ years (LSST)
Sanchez et al. (2014)
Weak Lensing requirements:
Scatter
Bias
i.e. a representative subset of your sample with spectroscopic redshifts
Neural Networks
Self-organizing Maps (SOMs)
Deep learning
Support Vector Machines (SVM)
Naive Bayes
Gaussian Processes
Generalized Linear Models
Bayesian Network
k-Nearest Neighbour
Boosted Decision Trees
Randomised Forests
Relevance vector machines
Radial basis function networks
Normalised inner product nearest neighbour
Directional neighbourhood fitting
Voronoi tesselation density estimator
Non-conditional density estimation
Dahlen et al. (2012)
7/11 submitted photo-z estimates significantly overconfident for 1-sigma errors
Wittman et al. (2016)
See also Bordoloi et al. (2010)
Dahlen et al. (2012)
= Median of all photo-z estimates
= Median of best 5 photo-z estimates
See also Carrasco Kind & Brunner (2014)
Also works for diff. templates with the same code
Masters et al. (2015)
Masters et al. (2015)
Masters et al. (2015)
Targeted spectroscopic follow-up of unexplored colour space (Underway): ~< 10k spectra
Ongoing spectroscopic surveys:
(e.g. VANDELS/HETDEX)
New massively multiplexed spectroscopic surveys -
Subaru/PFS and WHT/WEAVE in the North: ~1m+ spectra
Faint X-ray sources better fit by 'normal' galaxies
Salvato et al. (2009/11)
* Carrasco Kind and Brunner (2014)
Bayesian model combination/averaging (BMC/BMA)*
Spectroscopic sample (Bootes)
AGN/QSO Templates
Stellar Templates
(ML estimates)
EAZY
SWIRE
'Atlas'
Stellar only
Stellar + AGN
Stellar + AGN
Duncan et al. (in prep)
EAZY
SWIRE
'Atlas'
Stellar only
Stellar + AGN
Stellar + AGN
Duncan et al. (in prep)
Fixed redshift bin
0.4 < z < 0.8
1. Full multi-wavelength optical photometry in Tier-2/Tier-3 fields will be available through HELP
2. Optimised photometric redshifts will also be available as and when each field is completed by HELP
3. For all but the highest luminosity sources, photo-z accuracy should be comparable to normal galaxies (more work required)
But...these luminous sources will be targeted by WEAVE