Specifying filters

Included filters

The blendz installation includes filter response curves from several instruments. The filter_path configuration option points to the folder where these are stored by default, and so they can be specified in the filters configuration option using the following names:

SDSS

Described in Stoughton et al. (2002)

Configuration option Description
sdss/u u
sdss/g g
sdss/r r
sdss/i i
sdss/z z

Viking

Described in Edge et al. (2013)

Configuration option Description
viking/h H
viking/j J
viking/k K
viking/y Y

LSST

Described in Abell et al.(2009)

Configuration option Description
lsst/u u
lsst/g g
lsst/r r
lsst/i i
lsst/z z
lsst/y Y

HST

As packaged in BPZ (Benitez (2000) )

Configuration option Description
hst/F110W F110W
hst/F160W F160W
hst/F435W F435W
hst/F606W F606W
hst/F775W F775W
hst/F850LP F850LP

Loading custom filters

Each custom filter can be specified by a single plaintext file of two columns, wavelength (Angstroms) in the first, and the filter response in the second, separated by whitespace, e.g.

912.0  0.0329579004203
920.0  0.0332336431181
930.0  0.0335731230922
940.0  0.033939398051
950.0  0.0342922864396
960.0  0.0346317644112
970.0  0.0349582358084
980.0  0.0352716948728
990.0  0.0355717998991
1000.0  0.0358573156287
1010.0  0.0361306346606

The filter_path configuration option should point to the folder where these files are stored, and each entry in the filters configuration option should be the path (including the name and file extension) relative to filter_path, i.e., for the following folder layout:

containing_folder/
├── filters/
│   ├── instrument_one/
│   │   ├── filter_one.txt
│   │   ├── filter_two.txt
│   ├── instrument_two/
│   │   ├── filter_three.txt
│   │   ├── filter_four.txt

you should set the configuration options to:

filter_path = "containing_folder/filters"
filters = ["instrument_one/filter_one.txt", "instrument_one/filter_two.txt", \
           "instrument_two/filter_three.txt", "instrument_two/filter_four.txt"]

The default filters only don’t need file extensions as they are saved in plaintext files without file extensions.