# Extinction Map of the Galactic center: OGLE-II Galactic bulge fields

This directory contain the extinction maps of OGLE-II Galactic bulge fields.
You can use the extinction maps (text fromat) or Perl script to get the
extinction value.

**Note: The user should be aware of the zero point of the extinction
may be non-accurate. (see the paper)

Contents:

EVImaps/sc*.map.gz           # extinction maps for bul_sc* field
                             # Columns are as follows;

# n  X  Y   E(V-I)  err   AV  err   AI  err    Nall cut VIsdev   NRC cut VIsdev  grp
#
#1   n         :  bin number
#2   X         :  x axis of bin
#3   Y         :  x axis of bin
#4,5 E(V-I) err:  Reddening and error in magnitude 
#6,7 AV     err:  V-band extinction and error in magnitude
#8 9 AI     err:  I-band extinction and error in magnitude
#10  Nall      :  Number of all stars in this bin
#11  cut       :  Number of all stars in this bin after 2 sigma clip
#12  VIsdev    :  Standard deviation in I-V color of all stars in this bin
#13  NRC       :  Number of RCG stars in this bin
#14  cut       :  Number of RCG stars in this bin after 2 sigma clip
#15  VIsdev    :  Standard deviation in I-V color of all stars in this bin
#16  grp       :  Flag. Group number to which this bin belongs for normal bin
#                 but negative value for the bin with a problem (see the text)

                             # Note these err are relative.
                             # additional zero point errors are given at the end of files
                             # E(V-I)0err= 0.0244   AV0err= 0.0480   AI0err= 0.0236
                             # Other informations such as bin size are also at the end of files


bin/radec2xy                 # Linux machine Exec. code to transform (RA,Dec) to (x,y)
bin/xsplin2                  # Linux machine Exec. code for interpolation 
bin_sun/radec2xy             # Sun   machine Exec. code to transform (RA,Dec) to (x,y)


get_EVI_xy.pl                # Perl script to get extinction by (x,y) pixel coordinate
get_EVI_xy_interp.pl         # with interpolation 
get_EVI_RADec.pl             # by (RA, Dec) coordinate. Note change the path in the script
                             # (5th line) to bin_sun/radec2xy for Sun machine
get_EVI_RADec_interp.pl      # with interpolation


#----------------------Examples how to use Perl script-----------------------------------------------
# get_EVI_xy.pl  can be used on any machine
# get_EVI_RADec.pl can be used on Linux machine and on Sun by changing the path in the script
# (5th line) to bin_sun/radec2xy 
# Scripts with interpolation can be used on Linux machine only.
# We don't recommend to use a interpolation for a lot of stars because it is slow.


get_EVI_xy.pl     1  1023.8      4096.3      # bul_sc1 (x,y)=(1023.8, 4096.3)
get_EVI_RADec.pl  1  18:02:32.5  -29:57:41   # bul_sc1 (RA, Dec)=(18:02:32.5, -29:57:41)

  #Both will give the  same answer:
   13 56   0.7240 0.0114  1.4221 0.0232  0.6981 0.0125   0.0244  0.0480  0.0236  30

  #Values represent:
   X  Y    E(V-I)  err      AV    err      AI    err     E(V-I)0err AV0err AI0err grp



get_EVI_xy_interp.pl    1 1023.8 4096.3
get_EVI_RADec_interp.pl 1 18:02:32.5 -29:57:41


  #Both will give same answer:
   13 56   0.7240 0.0114  1.4221 0.0232  0.6981 0.0125   0.0244  0.0480  0.0236  30 :ACTUAL
   13 56   0.7428 0.0114  1.4591 0.0232  0.7163 0.0125   0.0244  0.0480  0.0236  30 :INTERP


  #First line the is same as in above example.
  #Second line is with values given by interpolation.