Information on Service 'Gravitational arc candidates in the CFHTLS-Archive-Research Survey CARS'

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Candidate gravitational arcs in the 37 deg^2 of CFHTLS-Archive-Research Survey (CARS). The data include their post-stamp images, astrometry, photometry (u*,g',r',i'), geometric properties (length, length-to-width ratio, profile curvature, area), and photometric redshifts. The arc candidates were selected booth with an automatic arcfinder, based on a tailored image segmentation and a color selection, and by visually inspecting the survey.

For a list of all services and tables belonging to this service's resource, see Information on resource 'Gravitational arc candidates in the CFHTLS-Archive-Research Survey CARS'

Overview

You can access this service using:

This service is published as follows:

local means it is listed on our front page, ivo_managed means it has a record in the VO registry.

Input Fields

The following fields are available to provide input to the service (with some renderers, some of these fields may be unavailable):

NameTable Head DescriptionUnitUCD
arc_length Arc length Length of the arc (see paper for construction). deg phys.angSize;src
carsfield CARS field CARS field identifier N/A meta.id;obs.field
DEC Delta (ICRS) Declination (ICRS decimal) deg pos.eq.dec
hscs_pos Position/Name Coordinates (as h m s, d m s or decimal degrees), or SIMBAD-resolvable object N/A N/A
hscs_sr Search radius Search radius in arcminutes N/A N/A
MAXREC Match limit Maximum number of records returned. Pass 0 to retrieve service parameters. N/A N/A
RA Alpha (ICRS) Right Ascension (ICRS decimal) deg pos.eq.ra
RESPONSEFORMAT Output Format File format requested for output. N/A meta.code.mime
SR Search Radius Search radius deg N/A
VERB Verbosity Exhaustiveness of column selection. VERB=1 only returns the most important columns, VERB=2 selects the columns deemed useful to the average user, VERB=3 returns a table with all available columns. N/A N/A
z_lens Lens z Photometric redshift of the lens (from CARS catalog). N/A src.redshift.phot

Default Output Fields

The following fields are contained in the output by default. More fields may be available for selection; these would be given below in the VOTable output fields.

NameTable Head DescriptionUnitUCD
_r Dist. Distance to cone center deg pos.distance
arc_area Area Area of the arc (see paper for construction). deg**2 phys.angSize;src
arc_curv Curvature Curvature of the arc (see paper for construction). deg**-1 src.morph.param
arc_l_w L/W Length to width ratio for the arc (see paper for construction). N/A phys.size;arit.ratio
arc_length Arc length Length of the arc (see paper for construction). deg phys.angSize;src
carsfield CARS field CARS field identifier N/A meta.id;obs.field
catnr Ext. id Catalog number of previously known arcs N/A meta.id.cross
dej2000 Dec Declination of the center, ICRS deg pos.eq.dec;meta.main
gprime mag_g arc g' aperture magnitude (based on segmentation) mag phot.mag;em.opt.V
img_g g band image CARS image in the g band. N/A meta.ref.url
img_i i band image CARS image in the i band. N/A meta.ref.url
img_r r band image CARS image in the r band. N/A meta.ref.url
img_u u band image CARS image in the u band. N/A meta.ref.url
iprime mag_i arc i' aperture magnitude (based on segmentation) mag phot.mag;em.opt.I
matid Id Identification number within carsarcs Note d N/A meta.id;meta.main
preview Preview Preview image N/A meta.ref.url
qual_ass Quality Quality assessment Note q N/A meta.code.qual
raj2000 RA Right ascension of the center, ICRS deg pos.eq.ra;meta.main
rprime mag_r arc r' aperture magnitude (based on segmentation) mag phot.mag;em.opt.R
uprime mag_u arc u' aperture magnitude (based on segmentation) mag phot.mag;em.opt.U
z_lens Lens z Photometric redshift of the lens (from CARS catalog). N/A src.redshift.phot

VOTable Output Fields

The following fields are available in VOTable output. The verbosity level is a number intended to represent the relative importance of the field on a scale of 1 to 30. The services take a VERB argument. A field is included in the output if their verbosity level is less or equal VERB*10.

NameTable Head DescriptionUnitUCD Verb. Level
matid Id Identification number within carsarcs Note d N/A meta.id;meta.main 1
raj2000 RA Right ascension of the center, ICRS deg pos.eq.ra;meta.main 1
dej2000 Dec Declination of the center, ICRS deg pos.eq.dec;meta.main 1
arc_length Arc length Length of the arc (see paper for construction). deg phys.angSize;src 1
arc_l_w L/W Length to width ratio for the arc (see paper for construction). N/A phys.size;arit.ratio 1
preview Preview Preview image N/A meta.ref.url 5
z_lens Lens z Photometric redshift of the lens (from CARS catalog). N/A src.redshift.phot 5
qual_ass Quality Quality assessment Note q N/A meta.code.qual 5
_r Dist. Distance to cone center deg pos.distance 10
carsfield CARS field CARS field identifier N/A meta.id;obs.field 15
arc_curv Curvature Curvature of the arc (see paper for construction). deg**-1 src.morph.param 15
arc_area Area Area of the arc (see paper for construction). deg**2 phys.angSize;src 15
uprime mag_u arc u' aperture magnitude (based on segmentation) mag phot.mag;em.opt.U 15
gprime mag_g arc g' aperture magnitude (based on segmentation) mag phot.mag;em.opt.V 15
rprime mag_r arc r' aperture magnitude (based on segmentation) mag phot.mag;em.opt.R 15
iprime mag_i arc i' aperture magnitude (based on segmentation) mag phot.mag;em.opt.I 15
catnr Ext. id Catalog number of previously known arcs N/A meta.id.cross 15
img_u u band image CARS image in the u band. N/A meta.ref.url 15
img_g g band image CARS image in the g band. N/A meta.ref.url 15
img_r r band image CARS image in the r band. N/A meta.ref.url 15
img_i i band image CARS image in the i band. N/A meta.ref.url 15
err_uprime σ(mag_u) Error in u magnitude; estimated by image noise including background subtraction uncertainty. mag stat.error;phot.mag;em.opt.U 25
err_gprime σ(mag_g) Error in g magnitude; estimated by image noise including background subtraction uncertainty. mag stat.error;phot.mag;em.opt.V 25
err_rprime σ(mag_r) Error in r magnitude; estimated by image noise including background subtraction uncertainty. mag stat.error;phot.mag;em.opt.R 25
err_iprime σ(mag_i) Error in i magnitude; estimated by image noise including background subtraction uncertainty. mag stat.error;phot.mag;em.opt.I 25
z_lens_err_plus +z Lens photometric redshift 1-sigma error taken from the CARS catalog. N/A stat.error;src.redshift.phot 25
z_lens_err_minus -z Lens photometric redshift 1-sigma error taken from the CARS catalog. N/A stat.error;src.redhshift.phot 25

Copyright, License, Acknowledgements

If you use this data, please cite the paper Maturi et al, 2014, given in the source metadata

VOResource XML (that's something exclusively for VO nerds)

Note d

The last character of the id is the detection type. This can be:

a
satisfies all criteria except color selection
b
was detected by the arcfinder but rejected by the geometrical constraints (L>15 pix, L/W<4)
c
was detected only by eye-ball checking
Note q

This flag takes the following values:

1
"unlikely": arc structures which seem physically associated to an astrophysical object, or which are relatively far from a possible lens
2
"unclear": arc structures with a very promising shape but still being of dubious origin
3
"unclear": a clear arc structure which curvature is displaced in such a way to "enclose" a possible lens cause of its origin, i.e. large ellipticals or significant concentrations of galaxies.