GTC OSIRIS Broad Band First Data Release: Detection catalogue

Documentation

Web access

The archive system implements a very simple search interface that permits queries by coordinates/radius and or range (*) of magnitudes. The default search radius is set to 5 arcsec. The user can also select the maximum number of sources to return (with values ranging from 10 to unlimited).

The result of the query is a HTML table with all the sources found in the archive fulfilling the search criteria. Detailed information on the output fields can be obtained placing the mouse over the question mark ("?") located close to the name of the column. Results can be sorted by just clicking on the name of the column. The archive implements the SAMP (Simple Application Messaging Protocol). SAMP allows applications to communicate with each other in a seamless and transparent way for the user. This way, the results of a query can be easily transferred to other VO applications by just clicking the "Send table to VO Apps" button.

Take into account that the number of displayed columns depends on the chosen verbosity.

(*) When a range is specified in a search the user must give both a minimum and maximum value for the corresponding quantity. If only a minimum value is given, all results with values larger than that will be obtained. If only a maximum value is given, all results with values smaller than that will be obtained.

Virtual Observatory access

The Virtual Observatory (VO) is an international initiative whose primary goal is to provide an efficient access and analysis of the information hosted in astronomical archives and services. Having a VO-compliant archive is an important added value for an astronomical project to guarantee the optimum scientific exploitation of their datasets.

Our archive system has been designed following the IVOA standards and requirements. In particular, it implements the Cone Search protocol, a standard defined for retrieving records from a catalogue of astronomical sources. The query made through the Cone Search service describes a sky position and an angular distance, defining a cone on the sky. The response returns a list of astronomical sources from the catalogue whose positions lie within the cone, formatted as a VOTable.

Frequently Asked Questions

How to make a query by magnitudes?

Click "Clean".
Fill in the appropriate boxes in the "additional search fields".
Mark the "Don't use coordinates as search criterion" checkbox if you don't want to restrict by coordinates (or uncheck it otherwise).
Click "Search"

Parameters contained in the source catalogue.

Parameter	Units	Description
RAJ2000	deg	Right Ascension (J2000).
DEJ2000	deg	Declination (J2000).
eRA	arcsec	Right Ascension uncertainty (eRAJ2000 * cos DEJ2000).
eDE	arcsec	Declination uncertainty.
ID_source	-	Unique source identifier. It follows an IAU-style designation of the form "GTC - OSIRIS - BBI - DR1 - JHHMMSS.ss+DDMMSS.s", where "GTC - OSIRIS - BBI - DR1" refers to the telescope (GTC ), the instrument (OSIRIS ), the observing mode (Broad Band Image) and data release (DR1). The remaining string denotes the J2000 coordinates in sexagesimal format.
ID_detection	-	Detection identifier composed by the ID source and " n", where n is an integer going from 1 to the total number of detections of the source.
Image_url	-	URL access to the FITS image in which the detection has been made.
Xmag_psf	mag	PSF calibrated magnitude. X stands for g, r, i and z.
eXmag_psf	mag	PSF calibrated magnitude error. X stands for g, r, i and z.
Flag_psf	-	Flag for PSF calibrated magnitude. "A" stands for PSF calibrated magnitudes within the interval of magnitudes used for the photometric calibration. "B" stands for PSF calibrated magnitudes fainter than the faintest magnitude used for the photometric calibration. "C" stands for PSF calibrated magnitudes brighter than the brightest magnitude used for the photometric calibration.
Xmag_auto	mag	AUTO calibrated magnitude. X stands for g, r, i and z.
eXmag_auto	mag	AUTO calibrated magnitude error. X stands for g, r, i and z.
Flag_auto	-	Flag for AUTO calibrated magnitude. "A" stands for AUTO calibrated magnitudes within the interval of magnitudes used for the photometric calibration. "B" stands for AUTO calibrated magnitudes fainter than the faintest magnitude used for the photometric calibration. "C" stands for AUTO calibrated magnitudes brighter than the brightest magnitude used for the photometric calibration.
Xmag_aperY_inst	mag	Instrumental aperture photometry. X stands for the four g, r, i, z and Y stands for the three apertures defined in Section 4.
eXmag_aperY_inst	mag	Instrumental aperture photometric errors. X stands for g, r, i, z and Y stands for the three apertures defined in Section 4.
Xmag_model_inst	mag	Instrumental MODEL photometry. X stands for the four g, r, i, z.
eXmag_model_inst	mag	Instrumental MODEL photometric errors. X stands for the four g, r, i, z.
Elongation	-	Elongation of the detection defined as A/B.
Ellipticity	-	Ellipticity of the detection defined as 1 - B/A.
FWHM	arcsec	Full width half maximum of the detection.
SNR	-	Signal to noise ratio.
MJD	d	Modified Julian Date of the observation.
Type	-	Indicates whether the detection is point-like ("P" or "P") or extense ("E" or "E") as explained in Section 7.1.2.
cl	-	Point-like coefficient linked to each unique source. It is defined as the ratio between number of point-like ("P" or "P") detections and the total number of point-like and extense ("E" or "E") classifications of the same source (num P /num P+E ). cl equal to 1 indicates that the source has been always classified as point-like, and cl equal to 0 indicates that the source has been always classified as extense.
Flag source	-	Indicates if it is a primary (p) or secondary (s) detection, as defined in Section 7.1.3.