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Archive Historical Help content

 

This page contains FAQs and tutorials that have become obsolete. It can be useful for users who store obsolete content (like tables or files) in their computers.

FAQs

 

Deletion date Question Answer
2024/09/06 Why are the column names of my uploaded table formatted to lowercase? The ADQL language is case-insensitive (unless double quotes are used; see Sects. 2 and 2.1.7 of the ADQL 2.1 recommendation standard). Because of this, if a table uploaded by a user contains column names with uppercase letters, the Gaia ESA Archive will automatically convert them to lowercase letters. To learn how to upload a table to the Archive please take a look at this tutorial.

 

Tutorials

 

DR3 EPOCH PHOTOMETRY (prior to GACS 3.6)

The serialisation of the epoch photometry in INDIVIDUAL data structure served before GACS 3.6 was based on the IVOA Time series cube data model. No metadata was added into the file header, and all the information was repeated through the output table so each row was self-contained. The table fields and their associated metadata is summarised in the table below, where the fields added by the Archive (and not included in the DPAC/RAW data model) are highlighted with bold fonts:

Field

Unit

Data type

UCD

UTYPE

source_id

 

long

meta.id;meta.main

 

transit_id

 

long

meta.id

 

band

 

string

instr.bandpass

ssa:DataID.Bandpass

time

d

double

time.epoch

 

mag

mag

double

phot.mag;em.opt

 

flux

'electron'.s**-1

double

phot.flux;stat.mean

 

flux_error

'electron'.s**-1

double

stat.error;phot.flux;em.opt

 

flux_over_error

 

double

stat.snr;phot.flux;em.opt

 

rejected_by_photometry

 

boolean

meta.code.status

 

rejected_by_variability

 

boolean

meta.code.status

 

other_flags

 

long

meta.code.status

 

solution_id

 

long

meta.version

 

 

Descriptions for the added fields:

band: Photometric band. Values: G (per-transit combined SM-AF flux), BP (blue photometer integrated flux), and RP (red photometer integrated flux).

rejected_by_photometry: Rejected by DPAC photometric processing. Unavailable or rejected by DPAC photometric processing, or negative (unphysical) flux.

other flags: Additional processing flags. This field contains extra information on the data used to compute the fluxes and their quality. It provides debugging information that may be safely ignored for many general purpose applications. The field is a collection of binary flags, whose values can be recovered by applying bit shifting and masking operations. Each band has different binary flags in different positions, as shown below. Bit numbering is as follows: least significant bit = 1 and most significant bit = 64.

  • G band:
    • Bit 1: SM transit rejected by photometric processing.
    • Bit 2 to 10: AF1 to AF9 transit rejected by photometric processing.
    • Bit 13: G band flux scatter larger than expected (all CCDs considered).
    • Bit 14: SM transit unavailable by photometric processing.
    • Bit 15 to 23: AF1 to AF9 transit unavailable by photometric processing.
  • BP band:
    • Bit 11: BP transit rejected by photometric processing.
    • Bit 24: BP transit photometry rejected by variability processing.
  • RP band:
    • Bit 12: RP transit rejected by photometric processing.
    • Bit 25: RP transit photometry rejected by variability processing.

 

Figure 1: excerpt from the DR3 Epoch Photometry table serialised in INDIVIDUAL structure as displayed by TOPCAT.