CDS publication tips

Why distribute your data through VizieR?

Which type of data can you send to VizieR?

1. Tables

2. Special cases: "Associated data", i.e.time series, spectra or images

How to send the above data?

Why distribute your data through VizieR?

• Data preservation
• Discovery : take advantage of the VizieR services allowing discovery, and a good data visibility
  
• Data access: VizieR assigns meta-data that enable discovery and data reuse.
  • VizieR data are available through the Virtual Observatory (VO)
    • load tables using TOPCAT or Aladin
    • load spectra using CASSIS or Splat
    • load images in Aladin
  • Query tables using ADQL/SQL with TAPVizieR
  • The VizieR Photometry viewer is another output using tables for which filters are assigned to create SEDs
• Simbad: VizieR tables with astronomical objects can be processed in SIMBAD. But What is SIMBAD? .

Which type of data can you send to VizieR?

1. Tables

Type of formats: machine-readable tables, csv, tsv, aligned ASCII files or FITS files are welcome.

The new submit web application allows different formats for tables including FITS and helps you to ingest your data.

If you choose a FITS format, you can previously test that your FITS table can be properly read by popular tools such as fitsview and topcat: fv or TOPCAT.

Here is a checklist of important data that should be associated to the table:

• An explanation is given for all the columns (at least a clear label; at best, few words of explanation)

• The unit is given for all the columns (when relevant)

• For tables with sources, there are as accurate as possible coordinates

  • A bonus would be to have their uncertainty

  • Another bonus would be to have their wavelength

• As recommended by the IAU, a non-altered name is given for the sources (in addition to the coordinates)

  • It is really much better to stick to the same name for an object from a table to another

• One column is homogeneous, i.e. not mixed with different measures having different units or errors mixed with limit values or flags.

• If the measures come from other papers, the reference(s) to the papers should be explicitly given using the bibcode.

2. Associated data : images, time-series, spectra

Acceptable /reusable file formats for associated data are (as above for tables) but also the following:

In order to index FITS formats as accurately as possible, several basic metadata are needed, usually readily provided by the telescope software and data processing pipelines such as IRAF and MIDAS, as fits header keywords.

As a good practice, any FITS header should provide:

• WCS projections for positions and spectral range, using
• standard FITS keywords described in the NASA FITS description.

For the sake of clarity and simplicity, we ask the authors, whenever possible, to stick to the "1 item = 1 file" rule, i.e. 1 star spectrum per file, for instance. In this simplest context, fits files should ideally also have only 1 hdu.

An automatic, supervised detection of the metadata is available in the new VizieR submit page. It resolves the most popular projections, data reduction software (IRAF, MIDAS) headers and recognizes FITS keywords given in the NASA FITS description.

A small checklist for providing correct headers:

• Positions

  • target name
  • coordinates: full WCS is recommended including the projection, the center ... (FITS cards: CRVAL, CDELT, CDi_j, CTYPE, CUNIT, CRPIX..)

• Wavelength(s) of observations

  • full WCS recommended including units (ex: IRAF WAT cards)

• Observation date

• Telescope : instrument and Facility

If your associated data are correctly described, then they are provided through the vizier associated data web page and through the Virtual Observatory (CASSIS, Splat, Aladin).

How to send the above data?

Submission page: http://cdsarc.u-strasbg.fr/viz-bin/Submit or using the beta submit interface.

In case of upload difficulties, please contact the staff at CDS (cats@cdsarc.u-strasbg.fr).

FTP deposit or e-mail : see the Publication support page (http://cds.u-strasbg.fr/vizier/submit.htx#ToC3)

-- EmmanuellePerret - 2016-05-25