# 14.7.2 epoch_photometry

Epoch photometry. Each row in this table contains the light curve for a given object in bands G, BP and RP as stored in the DataLink Massive data base. This table makes extensive use of array types. It can be obtained selecting the RAW data structure option. A flat table (sparse cube), which one photometric point per source per row can be obtained using INDIVIDUAL or COMBINED. The corresponding data model is described in class light_curve.
Note this table is not available through the main archive TAP interface, but via the Massive Data service, indexed by the VO Datalink protocol, described in Section 13.2.3.

Columns description:

solution_id : Solution Identifier (long)

All Gaia data processed by the Data Processing and Analysis Consortium comes tagged with a solution identifier. This is a numeric field attached to each table row that can be used to unequivocally identify the version of all the subsystems that where used in the generation of the data as well as the input data used. It is mainly for internal DPAC use but is included in the published data releases to enable end users to examine the provenance of processed data products. To decode a given solution ID visit https://gaia.esac.esa.int/decoder/solnDecoder.jsp

source_id : Unique source identifier (unique within a particular Data Release) (long)

A unique single numerical identifier of the source obtained from gaia_source (for a detailed description see gaia_source.source_id)

n_transits : Number of Gaia transits (short)

transit_id : Transit unique identifier (long)

For a given object, a transit comprises the different Gaia observations (SM, AF, BP, RP and RVS) obtained for each focal plane crossing.

g_transit_time : Transit averaged G band observing time (double, Time[Barycentric JD in TCB - 2455197.5 (day)])

Field-of-view transit averaged observation time in units of Barycentric JD (in TCB) in days -2,455,197.5, computed as follows. First the observation time is converted from On-board Mission Time (OBMT) into Julian date in TCB (Temps Coordonnée Barycentrique). Next a correction is applied for the light-travel time to the Solar system barycentre, resulting in Barycentric Julian Date (BJD). Finally, an offset of 2,455,197.5 days is applied (corresponding to a reference time $T_{0}$ at 2010-01-01T00:00:00) to have a conveniently small numerical value. Although the centroiding time accuracy of the individual CCD observations is (much) below 1 ms, this per-FoV observation time is averaged over typically 9 CCD observations taken in a time range of about 44 sec.

g_transit_flux : Transit averaged G band flux (double, Flux[e-/s] )

The average G flux value, a combination of individual SM-AF CCD fluxes

g_transit_flux_error : Transit averaged G band flux error (double, Flux[e-/s] )

The uncertainty flux_error on flux is the uncertainty on the weighted mean G flux of the set of SM/AF individual CCD observations for the transit. This accounts for intrinsic scatter in the data. The exact formula and further details are given in Carrasco, J. M. et al. (2017).

g_transit_flux_over_error : Transit averaged G band flux divided by its error (float)

Mean flux in the band divided by its error.

g_transit_mag : Transit averaged G band Vega magnitude (double, Magnitude[mag])

G band Vega magnitude. It is computed from the flux applying the DR2 zero-point defined in https://www.cosmos.esa.int/web/gaia/iow_20180316

g_transit_n_obs : Number of CCD observations contributing to transit averaged G band flux (byte)

Number of CCD transits contributing to the average G flux (g_flux and g_flux_error). The exact strips going into the average can be determined from statusFlag.

bp_obs_time : BP CCD transit observing time (double, Time[Barycentric JD in TCB - 2455197.5 (day)])

Observation time of the BP CCD transit in units of Barycentric JD (in TCB) in days -2,455,197.5, computed as follows. First the observation time is converted from On-board Mission Time (OBMT) into Julian date in TCB (Temps Coordonnée Barycentrique). Next a correction is applied for the light-travel time to the Solar system barycentre, resulting in Barycentric Julian Date (BJD). Finally, an offset of 2,455,197.5 days is applied (corresponding to a reference time $T_{0}$ at 2010-01-01T00:00:00) to have a conveniently small numerical value.

bp_flux : BP band flux (double, Flux[e-/s] )

The integrated BP flux value of the transit. If the BP flux has been rejected or is unavailable, the flux will be set to NaN.

bp_flux_error : BP band flux error (double, Flux[e-/s] )

The uncertainty flux_error on flux is the uncertainty on the BP flux. This is the uncertainty associated with the single BP CCD transit available for a FoV transit. It includes photon noise and all applicable calibration errors. If the BP flux has been rejected or is unavailable, the value will be set to NaN (in VOTable and FITS formats) and an empty string (in plain text CSV format).

bp_flux_over_error : BP band flux divided by its error (float)

Mean flux in the band divided by its error. If the BP flux has been rejected or is unavailable, this value will be set to NaN.

bp_mag : BP band Vega magnitude (double, Magnitude[mag])

BP band Vega magnitude. It is computed from the flux applying the DR2 zero-point defined in https://www.cosmos.esa.int/web/gaia/iow_20180316

rp_obs_time : RP CCD transit observing time (double, Time[Barycentric JD in TCB - 2455197.5 (day)])

Observation time of the RP CCD transit in units of Barycentric JD (in TCB) in days -2,455,197.5, computed as follows. First the observation time is converted from On-board Mission Time (OBMT) into Julian date in TCB (Temps Coordonnée Barycentrique). Next a correction is applied for the light-travel time to the Solar system barycentre, resulting in Barycentric Julian Date (BJD). Finally, an offset of 2,455,197.5 days is applied (corresponding to a reference time $T_{0}$ at 2010-01-01T00:00:00) to have a conveniently small numerical value.

rp_flux : RP band flux (double, Flux[e-/s] )

The integrated RP flux value of the transit. If the RP flux has been rejected or is unavailable, the flux will be set to NaN.

rp_flux_error : RP band flux error (double, Flux[e-/s] )

The uncertainty flux_error on flux is the uncertainty on the RP flux. This is the uncertainty associated with the single RP CCD transit available for a FoV transit. It includes photon noise and all applicable calibration errors. If the RP flux has been rejected or is unavailable, the value will be set to NaN (in VOTable and FITS formats) and an empty string (in plain text CSV format).

rp_flux_over_error : RP band flux divided by its error (float)

Mean flux in the band divided by its error. If the RP flux has been rejected or is unavailable, this value will be set to NaN.

rp_mag : RP band Vega magnitude (double, Magnitude[mag])

RP band Vega magnitude. It is computed from the flux applying the DR2 zero-point defined in https://www.cosmos.esa.int/web/gaia/iow_20180316

photometry_flag_noisy_data : G band flux scatter larger than expected by photometry processing (all CCDs considered) (boolean)

photometry_flag_sm_unavailable : SM transit unavailable by photometry processing (boolean)

photometry_flag_af1_unavailable : AF1 transit unavailable by photometry processing (boolean)

photometry_flag_af2_unavailable : AF2 transit unavailable by photometry processing (boolean)

photometry_flag_af3_unavailable : AF3 transit unavailable by photometry processing (boolean)

photometry_flag_af4_unavailable : AF4 transit unavailable by photometry processing (boolean)

photometry_flag_af5_unavailable : AF5 transit unavailable by photometry processing (boolean)

photometry_flag_af6_unavailable : AF6 transit unavailable by photometry processing (boolean)

photometry_flag_af7_unavailable : AF7 transit unavailable by photometry processing (boolean)

photometry_flag_af8_unavailable : AF8 transit unavailable by photometry processing (boolean)

photometry_flag_af9_unavailable : AF9 transit unavailable by photometry processing (boolean)

photometry_flag_bp_unavailable : BP transit unavailable by photometry processing (boolean)

photometry_flag_rp_unavailable : RP transit unavailable by photometry processing (boolean)

photometry_flag_sm_reject : SM transit rejected by photometry processing (boolean)

photometry_flag_af1_reject : AF1 transit rejected by photometry processing (boolean)

photometry_flag_af2_reject : AF2 transit rejected by photometry processing (boolean)

photometry_flag_af3_reject : AF3 transit rejected by photometry processing (boolean)

photometry_flag_af4_reject : AF4 transit rejected by photometry processing (boolean)

photometry_flag_af5_reject : AF5 transit rejected by photometry processing (boolean)

photometry_flag_af6_reject : AF6 transit rejected by photometry processing (boolean)

photometry_flag_af7_reject : AF7 transit rejected by photometry processing (boolean)

photometry_flag_af8_reject : AF8 transit rejected by photometry processing (boolean)

photometry_flag_af9_reject : AF9 transit rejected by photometry processing (boolean)

photometry_flag_bp_reject : BP transit rejected by photometry processing (boolean)

photometry_flag_rp_reject : RP transit rejected by photometry processing (boolean)

variability_flag_g_reject : Average G transit photometry rejected by variability processing (boolean)

Rejected by DPAC variability processing (or variability analysis), or negative (unphysical) flux.

variability_flag_bp_reject : BP transit photometry rejected by variability processing (boolean)

Rejected by DPAC variability processing (or variability analysis), or negative (unphysical) flux.

variability_flag_rp_reject : RP transit photometry rejected by variability processing (boolean)

Rejected by DPAC variability processing (or variability analysis), or negative (unphysical) flux.