GMOSAIC/GMAP  - GALEX Target Field of View Simulator    Karl Forster July 2007
====================================================

The GMOSAIC plot shows a 5 x 5 degree region of the sky centered on
the input coordinates. The field name and field center J2000 Equatorial
and Galactic coordinates are shown above the plot.

The GALEX field of view, circular with diameter 1.25 degrees, is
centered on the input coordinates and is plotted in black.

The background grayscale image shows the diffuse 100 micron emission
(MJy/sr) taken from the COBE normalized IRAS cirrus maps of Schlegel,
Finkbeiner, & Davis (1998). The maximum, minimum, and median 100
micron emission in the 5x5 region is given at the top of the page.
The graysacle is on a linear scale from the minimum (white) to maximum
(black) levels.

I100 = 0.73 MJy/sr corresponds to: E(B-V) ~ 0.015 
                                   AV ~ 0.0465 
                                   nHI ~ 9 x 10^19 cm-2 

I100 = 1.07 MJy/sr corresponds to: E(B-V) ~ 0.02
                                   AV ~ 0.062
                                   nHI ~ 1.2 x 10^20 cm-2

The positions of stars in the 5x5 degree target field are extracted
from three catalogs: TD-1 (Thompson et al. 1978), Tycho2 (Hog et
al. 2000), and SK2 (Myers et al. 2002). These positions are plotted
using 2 symbols:

Small green diamonds - stars with GALEX NUV fluxes estimated to be
                       min_nuv cts/second (see below) and so pose 
                       no threat to GALEX detectors.

Blue stars - Stars with GALEX NUV fluxes estimated to be >= min_nuv cts/s.
             The size of the stars indicates the estimated NUV count 
             rate (on a logarithmic scale). The scale for the blue 
             stars is given below the plot.

Also shown are the regions around the blue stars (hashed blue circles)
that must be avoided by the GALEX field of view to pass the star
brightness limits:

NUV Count Rate (counts/sec) / Distance from center of GALEX field 
                              of view (degrees)

   min_nuv / 0.75
     50000 / 0.88
    200000 / 1.00
    500000 / 1.50
   1000000 / 2.00
                                                         
Stars that fail any of these brightness limits are plotted in red and
the outer circle of the exclusion region is over-plotted with a red
dashed line.

min_nuv - this is a parameter that can be set when the plots are generated
          the limit is shown at the bottom of the plot as the first
          count rate where a violation can occur. The default value is 
          5000 cts/s but can be raised to 30000 cts/s.

GMAP enhancements
-----------------

When gmosaic is run using the gmap wrapper a number of additional
features may appear on the plots:

  Positions that were observed to be so bright that they caused
  detector overcountrate shutdowns are indicated by red circles of 1.2
  degree diameter with red/pink hatching. Red lines running NE-SW
  indicate NUV shutdowns, pink lines running NW-SE indicate FUV
  shutdowns.

  The Magellanic cloud exclusion regions will also appear as large red
  circles with vertical and horizontal lines on plots near the clouds.

  Planned targets in the field of view will be plotted as blue circles
  with 1.2 degree diameter and the target_id of the tiles will be
  printed centered on the blue circles.

  The positions of targets of interest (sometimes called science
  targets) can be plotted as red ellipses of varying sizes.

REFERENCES

Schlegel, D.J., Finkbeiner, D.P., & Davis, M. ApJ, 500, 525 (1998)
   "Maps of Dust IR Emission for Use in Estimation of Reddening and 
   CMBR Foregrounds"
   
Thompson, G.I., Nandy, K., Jamar, C., Monfils, A., Houziaux, L.,
Carnochan, D.J., & Wilson, R. (1978) The Science Research Council, U.K.
   "A compilation of absolute  stellar fluxes measured by the Sky Survey 
   Telescope (S2/68) aboard the ESRO satellite TD-1", 
   http://cdsweb.u-strasbg.fr/viz-bin/Cat?II/59B
   http://adsabs.harvard.edu/cgi-bin/bib_query?1982A&AS...49..427W

Hog E., Fabricius C., Makarov V.V., Urban S., Corbin T., Wycoff G., 
Bastian U., Schwekendiek P., Wicenec A., Astron. Astrophys. 355, L27 (2000)
   The Tycho-2 Catalogue of the 2.5 Million Brightest Stars, 
   http://www.astro.ku.dk/~erik/Tycho-2/

Myers et al. (2002) Goddard Space Flight Center, Flight Dynamics Division:
   SKY2000 Master Catalog, Version 4:
   http://mmfd.gsfc.nasa.gov/dist/generalProducts/attitude/ATT_SKY2KV1_aiaa_fnl.h