Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectroscopic Needs for Imaging Dark Energy Experiments: Photometric
  Redshift Training and Calibration   Large sets of objects with spectroscopic redshift measurements will be needed
for imaging dark energy experiments to achieve their full potential, serving
two goals:_training_, i.e., the use of objects with known redshift to develop
and optimize photometric redshift algorithms; and_calibration_, i.e., the
characterization of moments of redshift (or photo-z error) distributions.
Better training makes cosmological constraints from a given experiment
stronger, while highly-accurate calibration is needed for photo-z systematics
not to dominate errors. In this white paper, we investigate the required scope
of spectroscopic datasets which can serve both these purposes for ongoing and
next-generation dark energy experiments, as well as the time required to obtain
such data with instruments available in the next decade. Large time allocations
on kilo-object spectrographs will be necessary, ideally augmented by infrared
spectroscopy from space. Alternatively, precision calibrations could be
obtained by measuring cross-correlation statistics using samples of bright
objects from a large baryon acoustic oscillation experiment such as DESI. We
also summarize the additional work on photometric redshift methods needed to
prepare for ongoing and future dark energy experiments.

13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th