J/ApJS/194/40 Photometric Catalog of the Deep Ecliptic Survey (Buie+, 2011)
A large and faint photometric catalog on the ecliptic.
Buie M.W., Trilling D.E., Wasserman L.H., Crudo R.A.
<Astrophys. J. Suppl. Ser., 194, 40 (2011)>
=2011ApJS..194...40B 2011ApJS..194...40B
ADC_Keywords: Photometry ; Surveys ; Stars, faint
Keywords: catalogs - Kuiper belt: general - stars: general -
techniques: photometric
Abstract:
A photometric catalog, developed for the calibration of the Deep
Ecliptic Survey, is presented. The catalog contains 213272 unique
sources that were measured in V and R filters and transformed to the
Johnson-Cousins systems using the Landolt standard catalog. All of the
sources lie within 6° of the ecliptic and cover all longitudes
except for the densest stellar regions nearest the galactic center.
Seventeen percent of the sources in the catalog are derived from three
or more nights of observation. The catalog contains sources as faint
as R∼19 but the largest fraction fall in the R∼15-16 (V∼16-17)mag
range. All magnitude bins down to R=19 have a significant fraction of
objects with uncertainties ≤0.1mag.
Description:
Table 1 provides all the defined calibration field centers along with
the date each field was observed. The largest contribution was made by
the Lowell Observatory 0.8m telescope, during 2000-2006. Additional
contributions were made by the SMARTS 0.9m telescope, the University
of Arizona 1.5m Kuiper Telescope, and the Lowell Observatory 1.2m Hall
telescope. At all facilities, standard Johnson-Cousins V and R filters
were used to collect the raw photometric data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 87 2518 List of field centers
table2.dat 118 422 Nightly photometric transformation coefficients
table3.dat 76 4024119 Individual photometric measurements
table4.dat 137 213271 *Deep Ecliptic Survey (DES) photometric support
catalog
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Note on table4.dat: the catalog has one line less than announced in
the paper (213271 instead of 213272).
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See also:
J/ApJS/190/166 : Optical catalog of AKARI NEP-wide survey (Jeon+, 2010)
J/ApJS/191/222 : BLAST observations of the SEP field (Valiante+, 2010)
J/ApJS/172/583 : NEP source catalog (Hwang+, 2007)
J/PASJ/59/S529 : NEP deep survey at 11um (Lee+, 2007)
J/A+A/461/977 : Rosat North Ecliptic survey stellar population (Micela+, 2007)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Field identification (FNNNNN or FFNNNN) (1)
8- 9 I2 h RAh Hour of Right Ascension (J2000) (2)
11- 12 I2 min RAm Minute of Right Ascension (J2000) (2)
14- 19 F6.3 s RAs Second Right Ascension (J2000) (2)
21 A1 --- DE- Sign of the Declination (J2000) (2)
22- 23 I2 deg DEd Degree of Declination (J2000) (2)
25- 26 I2 arcmin DEm Arcminute of Declination (J2000) (2)
28- 32 F5.2 arcsec DEs Arcsecond of Declination (J2000) (2)
34- 43 A10 "YYYY/MM/DD" Date1 Date of observation #1 (G1)
45- 54 A10 "YYYY/MM/DD" Date2 Date of observation #2 (G1)
56- 65 A10 "YYYY/MM/DD" Date3 Date of observation #3 (G1)
67- 76 A10 "YYYY/MM/DD" Date4 Date of observation #4 (G1)
78- 87 A10 "YYYY/MM/DD" Date5 Date of observation #5 (G1)
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Note (1): Calibration field name. If the name starts with a single F, the
field is interior to a Deep Ecliptic Survey field of the same name.
If the name starts with FF, the field is specially defined to cover
one or more followup fields at non-standard locations.
Note (2): Coordinate was used for target field placement but coincides
with a 17mag star for F fields and an 18mag star for FF fields.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "YYYY/MM/DD" ObsDate UT Date of observation (G1)
12- 19 A8 --- Inst Name of instrument used (G2)
21 A1 --- Filt [RV] Name of filter (3)
23 A1 --- C1 [V] Name of first color filter (4)
25 A1 --- C2 [R] Name of second color filter (4)
27- 33 F7.5 mag Ext Atmospheric extinction (5)
35- 41 F7.5 mag e_Ext Uncertainty on the extinction (6)
43 I1 --- fE [0] Extinction fitted (0) or forced (1) (7)
45- 51 F7.4 --- CTerm Color term
53- 58 F6.4 --- e_CTerm Uncertainty on the color term (6)
60 I1 --- fC [0/1] Color term fitted (0) or forced (1) (7)
62- 69 F8.5 mag/h dtk Time dependent extinction term (6)
71- 77 F7.5 mag/h e_dtk Uncertainty on the dtk (6)
79 I1 --- fd [0/1] Term fitted (0) or forced (1) (7)
81- 93 F13.5 d JDref Reference JD time for dtk (8)
95-100 F6.3 mag ZP Photometric zero-point (9)
102-106 F5.3 mag e_ZP uncertainty on ZP (6)
108 I1 --- fZ [0] Term fitted (0) or forced (1) (7)
110-112 I3 --- Nobs Number of standard star measurements (10)
114-118 F5.2 --- chi2 Goodness of fit statistic (11)
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Note (3): Name of the Johnson filter used (either V or R)
Note (4): C1 and C2 define the standard color used in the transformation
coefficients. This color is (V-R) for all observations.
Note (5): The airmass computation used is the Tholen approximation.
Note (6): These uncertainties reflect a final a posteriori adjustment to
the individual standard star measurement errors to force the final
fit to have a reduced chi-squared value of 1.0
Note (7): Each term can be either fitted or forced to a known value. The
bit indicates if the term was fitted with a value of 0 or forced with
a value of 1. This information is not needed in order to evaluate the
photometric transformation.
Note (8): Mean UT time of all the fitted observations. This is used as the
reference time for the time dependant extinction calculation.
Note (9): The zero-point (Z) used to determine the transformation
coefficients following equation (1):
M=m-kX+εC-η(t-t0)X+Z
where M is the standard magnitude, m is the instrumental magnitude,
k is the extinction coefficient, X is the airmass, ε is the
color coefficient, C is the standard color for the object, η is
the time-dependent extinction coefficient, t is the time of
observation, t0 is the reference time for night. See section 3.1.
Note (10): The fitting process uses robust statistics. The number reported in
this column is the final number that were kept in the final fitting pass.
Note (11): The value reported here is the weighted reduced chi-square from
the fit using the original errors. This value is used to compute a
posteriori adjustment reflect in the transformation uncertainties.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "YYYY/MM/DD" ObsDate UT Date of observation (G1)
12- 18 A7 --- Inst Name of instrument used (G2)
20- 32 F13.5 d JD UT Julian date of measurement (3)
34- 43 F10.8 rad RArad Measured Right Ascension (J2000) (4)
45- 55 F11.8 rad DErad Measured Declination (J2000) (4)
57 A1 --- Filt [RV] Filter used for measurement
59- 61 A3 --- Col Color used for reduction (V-R) (5)
63- 69 F7.4 mag mag ? Calibrated standard magnitude (6)
71- 76 F6.4 mag e_mag ? Uncertainty on mag (7)
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Note (3): This value is the mid-time of the exposure from which the
observation was extracted; It may not match the ObsDate depending
on the longitude of the observatory.
Note (4): During the data reduction process, the positions of all sources
are independently measured on every image. These values here are the
measured positions in J2000 coordinates against the USNO-B1.0 catalog
Note (5): Standard color (V-R) used to derive the absolute photometry.
Note (6): Final measured standard magnitude of each source.
Note (7): Uncertainty on the final magnitude. Includes all sources of error
and a posteriori adjustments.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- [BTW2011] Catalog ID for source (1)
16- 25 F10.8 rad RArad Mean Right Ascension (J2000) (2)
27- 37 F11.8 rad DErad Mean Declination (J2000) (2)
39- 43 F5.3 arcsec e_RArad Uncertainty on RArad (3)
45- 49 F5.3 arcsec e_DErad Uncertainty on DErad (3)
51- 57 F7.4 mag Vmag Standard V magnitude for source (4)
59- 64 F6.4 mag e_Vmag Uncertainty on Vmag (4)
66- 72 F7.4 mag Rmag Standard R magnitude (4)
74- 79 F6.4 mag e_Rmag Uncertainty on Rmag (4)
81- 87 F7.4 mag V-R Standard V-R color index (4)
89- 94 F6.4 mag e_V-R Uncertainty on V-R (4)
96- 97 I2 --- o_Vmag Total number of V observations (5)
99-100 I2 --- o_Rmag Total number of R observations (5)
102-103 I2 --- Nbad Total of observations marked as bad (6)
105 I1 --- Vnn [1,8] Number of nights in final V average (7)
107 I1 --- Rnn [1,8] Number of nights in final R average (7)
109-115 F7.4 mag r'mag SDSS r' mag calculated from V,R (8)
117-122 F6.4 mag e_r'mag Uncertainty on r'mag (8)
124-130 F7.4 mag g'-r' SDSS g'-r' color index from V,R (8)
132-137 F6.4 mag e_g'-r' Uncertainty on g'-r' (8)
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Note (1): The object name is provided as a unique string and is built from
the measured position of the source. The sky is gridded into 3arcsec
squares and there is at most, by definition, one source per square.
The cos(dec) factor is included. Each square is assigned a number
counting eastward from 0h RA and either counting north (+) or south
(-) from the equator. Converting back the id to ra,dec gives a
position that will be within 1.5arcsec of the true object position.
Note (2): These positions are the result of an unweighted average of the
individual measured positions for the source.
Note (3): Standard deviation of the mean of all the positions averaged into
the final position. The uncertainty is converted to true arcsec on the sky.
Note (4): These measure the averaged values and uncertainties for the
sources in the Johnson/Kron-Cousins/Landolt system. The V and R
measurements are independent. The V-R color and its error are
derived from the V and R measurements and is not independent.
Note (5): This is a count of the total number of observations.
Note (6): During the averaging process, statistically unlikely measurements
are excluded automatically. This field records how many, of either
filter, are excluded.
Note (7): This is a count of the total number of nights represented in the
final average.
Note (8): The final V and R data were transformed to SDSS r and g-r with
propagation of errors.
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Global Notes:
Note (G1): Each date is a UT date that identifies a single good night of
observations. The number of dates in Table1 indicates the number of
independent nights obtained on the field. Each date appear twice in
Table2 for the two filters used.
Note (G2): The name of the instrument also identifies the telescope used.
* "PCCD" and "NASAcam" were used on the Lowell Observatory 0.8-m telescope.
* "SMARTS" is the system used at CTIO for the SMARTS telescope.
* "SITE2k" is the camera used at the Lowell Observatory 1.2-m telescope.
* "ccd21big" also known as "2KBigCCD" device is used at the
Steward Observatory 1.54m Kuiper telescope.
History:
* 01-Aug-2011: From electronic version of the journal
* 26-Sep-2011: more complete version of Table 3
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 01-Aug-2011