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VIPERS PDR-1 data release: Photometric parent catalogs
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Columns description
===================

This table contains photometric data for the VIPERS area. Photometric
data are extracted from 1)the CFHTLS T0005 limited to apparent magnitude
i(AB) < 24.0 (after correction for Galactic extinction) and 2) the
CFHTLS T0007 data release, matched with the previous catalogue.
For further details please refer to the VIPERS survey description paper
Guzzo et al. 2013 (http://arxiv.org/abs/1303.2623), and to the PDR-1 
presentation paper Garilli et al. 2013 (http://arxiv.org/abs/1310.1008).


id_IAU and num
~~~~~~~~~~~~~~

VIPERS object name, according to IAU standards. The name is composed of
the prefix VIPERS plus the internal identification number. The internal
id number (num) is in the form
   attxxxxxx
where
    a identifies the sky area (1 for W1 and 4 for W4),
    tt identifies the CFHTLS tile number where the object is located,
    xxxxxx is the original CFHTLS ID within the tile.
The correspondence between our tile identifier and the official CFHTLS
tile name is provided in Guzzo et al. 2013.



alpha and delta
~~~~~~~~~~~~~~~

J2000 equatorial coordinates in degrees.



selmag and errselmag
~~~~~~~~~~~~~~~~~~~~

i_AB selection magnitude and error. The selection magnitude comes from
CFHTLS T0005 catalogue.



u,g,r,i,z,erru,errg,errr,erri,errz CFHTLS T0005 magnitudes and errors
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Magnitudes from the CFHTLS T0005 catalogue, supplemented by T0006
catalogue in some specific cases. See Guzzo et al. 2013, section 3 and
appendix C, for details on the tile to tile color offests, as well as
for T0005 and T0006 catalogue differences.
All magnitudes are given in the AB system, and are corrected for
Galactic extinction as follows:

    u = u_raw - 4.716 * E(B-V)
    g = g_raw - 3.654 * E(B-V)
    r = r_raw - 2.691 * E(B-V)
    i = i_raw - 1.998 * E(B-V)
    z = z_raw - 1.530 * E(B-V)

where E(B-V) is the extinction factor (color excess).
When an object has not been observed in a given band, magnitude and
error are set equal to -99. When a magnitude (and its error) could not
be measured, these values are set to 99. 



u_T07,g_T07,r_T07,i_T07,z_T07,erru_T07,errg_T07,errr_T07,erri_T07,
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
errz_T07 CFHTLS T0007 magnitudes and errors
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Magnitudes from the CFHTLS T0007 catalogue.

    - All magnitudes are corrected for Galactic extinction using the
      same prescription as the one used for the T0005 ones.
    - When an object has not been observed in a given band, magnitude
      and error are set equal to -99.
    - When a magnitude (and its error) could not be measured, these
      values are set to 99.
    - Objects observed in i band, have y magniudes set to -99.99. 

Objects observed in y band instead of i band, have i magniudes set to
-99.99.


Details on T0007-T0005 matching
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Object matching was carried out for each 1 sq deg tile using a 0.6
arcsec search radius. Almost all objects in T0005 have a unique match in
T0007 within the search radius.

For the few object for which no match has been found, T0007-like
magnitudes have been derived from T0005 in the following way

    - For each tile and each filter, using all matched objects with 
      18.0<selmag <22.5 a median T0007 to T0005 has been coomputed
    - T0007-like magnitueds are obtained by applying the offest to T0005
      magnitudes
    - Magnitude uncertainties are the original T0005 values. 


Details on i vs. y filter
^^^^^^^^^^^^^^^^^^^^^^^^^
In 7 tiles, the T0007 i-band data were taken with a modified i filter,
called y filter in the Terapix documentation.The affected tiles are:
W1_tile06, W1_tile07, W1_tile08, W1_tile16, W1_tile17, W1_tile18,
W4_tile09.

For these objects the i-band magnitude (i_T07) is set equal to -99.99,
and the y magnitude is provided (iy_T07).

For the objects in these tiles that do not have a matching counterpart
in the T0007 data, a T0007-like y magnitude has been computed starting
from the T0005 data as
    y(T0007) = i(T0005) + Delta(i,y) + slope * g(T0005)-i(T0005)

where Delta(i,y) and slope have been derived tile by tile fitting with
the above relation all matched objects with
    18.0 <selmag <22.5
and
    0 < g-i <3.5 



DeltaUG, DeltaGR, DeltaRI tile to tile color terms
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Tile-to-tile colors offsets used in the targets sample selection applied
to the CFHTLS T005 data (see Guzzo et al. 2013, section 3.1). For both
galaxy and AGN selection, the colors used to assign classFlag and
agnFlag can be obtained by applying the following corrections to the
colors derived from the magnitudes listed in the database:

    u-g_corr = u-g - DeltaUG
    g-r_corr = g-r - DeltaGR
    r-i_corr = r-i - DeltaRI


E_BV
~~~~

Extinction factor (color excess) E(B-V) derived from Schlegel's maps.


r2
~~

Radius enclosing half the object light as from CFHTLS T0005 catalogue,
measured in pixels 


r2_T07
~~~~~~

Radius enclosing half the object light as from CFHTLS T0007 catalogue,
measured in pixels 



classFlag
~~~~~~~~~

the VIPERS selection flag based on the CFHTLS T005 catalogue, where

  -99: problematic object, missing photometric data

  -88: problematic object, possibly saturated image

   -3: magnitude i < 17.5

   -2: magnitude i > 22.5

   -1: stellar like object according to the VIPERS star/galaxy
       separation criteria

    0: object with colors compatible with most galaxies at z < 0.5

    1: object with colors compatible with most galaxies at z > 0.5

See section 4 and Fig. 3 in Guzzo et al. 2013. 



agnFlag
~~~~~~~

A value equal to 1 is assigned to all AGN candidates, and equal to 0
otherwise. An object is an AGN candidate if it is stellar-like
(classFlag = -1) and exhibits colours that are clearly different from
those of the main stellar sequence (see equations 2 and 3 and Section
2.2 in Garilli et al. 2013) 



photoMask
~~~~~~~~~

Flag indicating whether the object falls within the photometric mask. 1
if the object is inside the mask, 0 if it is outside. Objects outside
the photometric mask have a less reliable photometry.



spectroMask
~~~~~~~~~~~

Flag indicating whether the object falls within the spectroscopic mask.
1 if the object is inside the mask, 0 if it is outside. Objects outside
the spectroscopic mask have not entered the mask preparation phase (see
Garilli et al. 2013 for details)


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03/10/2013