imaginglss.model.sfdmap module

Accesing SFD98 maps.

Most code taken from https://raw.githubusercontent.com/dstndstn/tractor/master/projects/desi/common.py , replaced the transformation with ours.

class imaginglss.model.sfdmap.SFDMap(ngp_filename=None, sgp_filename=None, dustdir=None)

Bases: object

SFDMap accesses the SFD98 Map. The map file shall be given in the constructor.

Notes

Use ebv() to query the E(B-V) values.

Attributes

extinctions

(dict) These values are not useful for us, but we keep them for reference. These come from Schlafly & Finkbeiner, arxiv 1012.4804v2, Table 6, Rv=3.1 but updated (and adding DES u) via email from Schlafly, decam-data thread from 11/13/2014, “New recommended SFD coefficients for DECam.” The coefficients for the four WISE filters are derived from Fitzpatrick 1999, as recommended by Schafly & Finkbeiner, considered better than either the Cardelli et al 1989 curves or the newer Fitzpatrick & Massa 2009 NIR curve not vetted beyond 2 micron). These coefficients are A / E(B-V) = 0.184, 0.113, 0.0241, 0.00910.

static bilinear_interp_nonzero(image, x, y)

ebv(ra, dec)

Directly query the SFD map and returns E(B-V).

Parameters:

ra : array_like

RA in degrees.

dec : array_like

DEC in degrees.

Returns:

ebv : array_like

E(B-V)

extinction(filts, ra, dec, get_ebv=False)

Returns the extinction for different filters.

Do not use this function; copied from old code. Use ebv() instead.

extinctions = {'SDSS u': 4.239, 'DES u': 3.995, 'DES g': 3.214, 'DES r': 2.165, 'DES i': 1.592, 'DES z': 1.211, 'DES Y': 1.064, 'WISE W1': 0.184, 'WISE W2': 0.113, 'WISE W3': 0.0241, 'WISE W4': 0.0091}