J/A+A/379/740 ESO Imaging Survey (EIS) (Arnouts+, 2001)
ESO imaging survey. Deep public survey: Multi-color optical data for the
Chandra Deep Field South.
Arnouts S., Vandame B., Benoist C., Groenewegen M.A.T., da Costa L.,
Schirmer M., Mignani R.P., Slijkhuis R.
<Astron. Astrophys. 379, 740 (2001)>
=2001A&A...379..740A 2001A&A...379..740A
ADC_Keywords: Surveys ; Galaxies, photometry
Keywords: catalogs - surveys - stars : general - galaxies : general
Abstract:
This paper presents multi-passband optical data obtained from
observations of the Chandra Deep Field South (CDF-S), located at
RA=03h32m, Dec=-27°48'. The observations were conducted at the
ESO/MPG 2.2 m telescope at La Silla using the 8kx8k Wide-Field Imager
(WFI). This data set, taken over a period of one year, represents the
first field to be completed by the ongoing Deep Public Survey (DPS)
being carried out as a part of the ESO Imaging Survey (EIS) project.
The paper describes the optical observations, the techniques
employed for un-supervised pipeline processing and the general
characteristics of the final data set. Image processing has been
performed using multi-resolution image decomposition techniques
adapted to the EIS pipeline. The automatic processing steps include
standard de-bias and flat-field, automatic removal of satellite tracks,
de-fringing/sky-subtraction, image stacking/mosaicking and astrometry.
Stacking of dithered images is carried out using pixel-based
astrometry which enables the efficient removal of cosmic rays and
image defects, yielding remarkably clean final images. The final
astrometric calibration is based on a pre-release of the GSC-II
catalog and has an estimated intrinsic accuracy of la 0.10 arcsec,
with all passbands sharing the same solution.
The data are taken in six different filters (U'UBVRI), cover an area
of about 0.25 square degrees, and reach the 5σ limiting
magnitudes of U'AB=26.0, UAB=25.7, BAB=26.4, VAB=25.4,
RAB=25.5 and IAB=24.7 mag, as measured within a 2xFWHM aperture.
The optical data covers an area of ∼0.1 square degree for which
moderately deep observations in two near-infrared bands are also
available, reaching 5σ limiting magnitudes of JAB∼23.4 and
KAB∼22.6. The current optical/infrared data also fully encompass the
region of the deep X-ray observations recently completed by the
Chandra telescope.
The optical data presented here, as well as the infrared data released
earlier, are publicly available world-wide in the form of fully
calibrated pixel and associated weight maps and source lists extracted
in each passband. These data can be requested through the URL
``http://www.eso.org/eis''.
Based on observations collected at the European Southern Observatory,
La Silla, Chile within program ESO 164.O-O561.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
up.dat 133 42087 U' band catalog (EIS product ID P_ID=35)
u.dat 133 37093 U band catalog (EIS product ID P_ID=34)
b.dat 133 74827 B band catalog (EIS product ID P_ID=28)
v.dat 133 45912 V band catalog (EIS product ID P_ID=31)
r.dat 133 65148 R band catalog (EIS product ID P_ID=30)
i.dat 133 43253 I band catalog (EIS product ID P_ID=29)
up_filt.dat 18 85 U' band filter transmission WFI U #877
u_filt.dat 18 500 U band filter transmission WFI U #841
b_filt.dat 18 500 B band filter transmission WFI B #842
v_filt.dat 18 500 V band filter transmission WFI V #843
r_filt.dat 18 500 R band filter transmission WFI R #844
i_filt.dat 18 132 I band filter transmission WFI I #854
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See also:
http://www.eso.org/eis : ESO Imaging Survey home page
J/A+A/384/81 : ESO Imaging Survey. CDF-S point sources (Hatziminaoglou+, 2002)
J/A+AS/137/75 : ESO Imaging Survey. IV. (Zaggia+, 1999)
J/A+AS/137/83 : ESO Imaging Survey. VII. (Scodeggio+, 1999)
Byte-by-byte Description of file: b.dat i.dat r.dat u.dat up.dat v.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [EIS]
4- 22 A19 --- EIS EIS identification name (from J2000 position)
24- 25 I2 h RAh RA hour (J2000)
26 A1 --- --- [:]
27- 28 I2 min RAm RA min
29 A1 --- --- [:]
30- 34 F5.2 s RAs [0,60] RA sec
36 A1 --- DE- Sign of declination
37- 38 I2 deg DEd DEC degrees (J2000)
39 A1 --- --- [:]
40- 41 I2 arcmin DEm DEC arcminutes
42 A1 --- --- [:]
43- 46 F4.1 arcsec DEs [0,60] DEC arcseconds
48- 52 F5.2 mag Mtot ?=99.00 Total magnitude (1)
54- 60 F7.2 mag e_Mtot ?=99.00 Error in total magnitude (1)
62- 66 F5.2 mag Miso Isophotal magnitude (1)
68- 71 F4.2 mag e_Miso Error in Isophotal magnitude (1)
73- 77 F5.2 mag Maper ?=99.00 Aperture magnitude (1)
79- 84 F6.2 mag e_Maper ?=99.00 Error in Aperture magnitude (1)
86- 93 F8.2 --- S/N Signal to Noise (S/N) (2)
95- 101 F7.2 arcsec2 area Isophotal area of the objects
103- 111 F9.2 arcsec Rh Half-light radius in arcseconds
113- 116 F4.2 --- b/a Minor to major-axis ratio
118- 123 F6.2 deg PA [-90,90] Position angle
125- 128 F4.2 --- Class Stellarity index computed by SExtractor (5)
130- 131 I2 --- Flag SExtractor flags (3)
133 I1 --- f_EIS [0,2] EIS Flags (4)
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Note (1): All magnitudes are given in the AB system.
Mtot: Total magnitude as measured by SExtractor
Miso: Isophotal magnitude as measured by SExtractor
Maper: aperture magnitude (3 arcsec diameter)
The magnitudes have been corrected for Galactic extinction
taken from Schlegel et al. (1998ApJ...500..525S 1998ApJ...500..525S).
The errors are those estimated by SExtractor and include only
the shot noise of the measured source and background counts.
Only objects detected with signal to noise ≥ 3 (based on the
isophotal magnitude errors) have been included.
Note (2): Signal to Noise (S/N).
An estimate of S/N of the detection from the inverse of the errors
estimated for the isophotal magnitude
Note (3): SExtractor flags - see Bertin 1998, SExtractor User's Guide v2.0
The extraction flags are coded as a sum of powers of 2:
1 = The object has neighbors, bright and close enough to
significantly bias the photometry, or bad pixels (more
than 10% of the integrated area affected).
2 = The object was originally blended with another one.
4 = At least one pixel of the object is saturated (or very close to).
8 = The object is truncates (to close to an image boundary).
16 = Object's aperture data are incomplete or corrupted.
32 = Object's isophotal data are incomplete or corrupted.
64 = A memory overflow occurred during deblending.
128 = A memory overflow occurred during extraction.
Note (4): EIS Flags
These flags are used to identify objects in regions with very low
weight or close to bright objects. Objects detected in regions with
weight ≥ 30 % of the maximum weight (proportional to the total
integration time) and not affected by bright stars have EIS flag=0.
Objects with weight less than 30%, located at the edges of the frame,
have EIS flag=1. EIS flag=2 indicates that the object is located in a
region masked out due to the presence of a bright object.
Note (5): a value close to 1 indicates a star; a value close to zero
indicates a galaxy.
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Byte-by-byte Description of file: *_filt.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 nm Lambda Wavelength
10- 18 F9.6 % Trans Transmission
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Acknowledgements: We kindly thank Christophe Benoit and Luiz da Costa
for their help in the preparation of this document.
(End) Mark Allen [CDS] 11-Apr-2002