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.

Spatial Coverage

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

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.