========================================================================
              Microlensing optical depth and event rate 
                 in the OGLE-IV Galactic plane fields

  P. Mroz, A. Udalski, M. K. Szymanski, I. Soszynski, P. Pietrukowicz,
    S. Kozlowski, J. Skowron, R. Poleski, K. Ulaczyk, M. Gromadzki, 
                  K. Rybicki, P. Iwanek, and M. Wrona
                  
========================================================================

pmroz@astro.caltech.edu

The directory structure is as follows:

README          - this file

table_A1.txt    - electronic version of Table A1 (basic information
                  about analyzed fields)

table_B1.txt    - electronic version of Table B1 (best-fitting 
                  parameters of the analyzed microlensing events)

table_B2.txt    - electronic version of Table B2 (possible microlensing
                  events)

table_C1.txt    - electronic version of Table C1 (surface density 
                  of stars in the OGLE GVS fields)

data/           - calibrated I-band photometry of individual events
data.tar.gz     - gzipped phot/ directory

data_c/         - calibrated I-band photometry of possible microlensing
                  events
data_c.tar.gz   - gzipped phot_c/ directory

eff21/          - event detection efficiencies in individual fields
                  (for sources brighter than I=21)
eff21.tar.gz    - gzipped eff21/ directory

eff20/          - event detection efficiencies in individual fields
                  (for sources brighter than I=20)
eff20.tar.gz    - gzipped eff21/ directory

Format of the photometry files:
------------------------------------------------------------------------
 Bytes  Format Units   Description
------------------------------------------------------------------------
  1- 13 F13.5  HJD     Heliocentric Julian Date
 15- 20 F6.3   mag     I magnitude
 22- 26 F5.3   mag     Magnitude error
------------------------------------------------------------------------

The I-band photometry is calibrated to the standard system. 
The uncertainties were corrected using the Skowron et al. (2016)'s 
method.

Format of the detection efficiency files:
------------------------------------------------------------------------
 Bytes  Format Units   Description
------------------------------------------------------------------------
  1-  5 F5.3   ---     Minimal log(t_E)
  7- 11 F5.3   ---     Maximal log(t_E)
 13- 20 F8.6   ---     Detection efficiency
------------------------------------------------------------------------