Explanatory Notes for V-band Photometric Data
Summary data tables for the V-band photometry can be found from
The following is a description of the data columns presented.
Links to the full-resolution flux spectra can be found from the links
to individual objects or from http://james.as.arizona.edu/~psmith/Fermi/DATA/specdata.html.
Column description for the V photometry summary tables:
- (1) Object name (also see the target lists).
- (2) Date (in the Greenwich time zone)
of the observation in yyyy-mm-dd format.
- (3) Universal Time of the observation in hh:mm:ss format. This time refers to the
approximate midpoint of the observation.
- (4) Julian Day as calculated from columns (2) and (3).
- (5) The comparison star used for the
Johnson V-band differential
The identification of the star within each field can be found by
clicking on the link.
The adopted Johnson V magnitudes of the
comparison stars can be found in this
- (6) The magnitude difference in the V bandpass between the AGN
and the comparison star in the sense of AGN - Comp.
The instrumental magnitudes of the AGN and the comparison star are determined
by using a synthetic Johnson V bandpass for spectroscopic data.
A Johnson V filter is used for the photometry when SPOL is used in
- (7) The uncertainty in magnitudes for
the measurement given in column (6) based on
- (8) The apparent V magnitude of the AGN. This column is left
blank if the V magnitude of the comparison star has not been determined.
The quoted value is simply the observed apparent magnitude. No correction has
been made for either interstellar extinction or the amount
of host galaxy starlight
that falls within the observing aperture.
- (9) The uncertainty in V (8). This estimate is made by adding in
quadrature the uncertainty given in column (7) and the uncertainty quoted in
the literature for the V magnitude of the comparison star
(see the TABLE summarizing the comparison stars).
This column is left blank if the brightness of the
comparison at V has not
Please contact Paul Smith (email@example.com) if you have questions concerning these web pages.