J/AcA/52/129 DIA OGLE2 candidate variable stars catalog (Wozniak+, 2002)
Difference image analysis of the OGLE-II Bulge data.
III. Catalog of 200000 candidate variable stars.
Wozniak P.R., Udalski A., Szymanski M., Kubiak M., Pietrzynski G.,
Soszinski I., Zebrun K.
<Acta Astron., 52, 129 (2002)>
=2002AcA....52..129W 2002AcA....52..129W
ADC_Keywords: Surveys ; Stars, variable ; Photometry
Keywords: Galaxy: center - catalogs - stars: variable: general
Abstract:
We present the first edition of a catalog of variable stars from
OGLE-II Galactic bulge data covering 3 years: 1997-1999. Typically
200-300 I band data points are available in 49 fields between -11 and
+11 degrees in galactic longitude, totaling roughly 11 square degrees
in sky coverage. Photometry was obtained using the Difference Image
Analysis (DIA) software and tied to the OGLE data base with the DoPhot
package. The present version of the catalog comprises 221801 light
curves. In this preliminary work the level of contamination by
spurious detections is still about 10%. Parts of the catalog have only
crude calibration, insufficient for distance determinations. The next,
fully calibrated, edition will include the data collected in year
2000. The data is accessible via ftp, at
ftp://bulge.princeton.edu/ogle/ogle2/bulge_dia_variables
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 144 221801 Catalog of the Candidate Variables in OGLE-II
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See also:
J/AcA/50/421 : OGLE-II DIA BUL_SC1 field (Wozniak, 2000)
J/AcA/51/175 : OGLE-II DIA microlensing events (Wozniak+, 2001)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- --- [BUL_SC]
7- 8 I2 --- Field Field number (field name is BUL_SCnn) (7)
11- 14 I4 --- Vno Number of variable candidate as returned by
the pipeline in the field (7)
17- 23 F7.2 pix Xpos X template coordinate (1)
26- 32 F7.2 pix Ypos Y template coordinate (1)
35- 44 F10.6 deg RAdeg Right ascension in decimal degrees (J2000)
47- 56 F10.6 deg DEdeg Declination in decimal degrees (J2000)
59- 60 I2 h RAh Right ascension (J2000)
61 A1 --- --- [:]
62- 63 I2 min RAm Right ascension (J2000)
64 A1 --- --- [:]
65- 69 F5.2 s RAs Right ascension (J2000)
72 A1 --- DE- Declination sign (J2000)
73- 74 I2 deg DEd Declination (J2000)
75 A1 --- --- [:]
76- 77 I2 arcmin DEm Declination (J2000)
78 A1 --- --- [:]
79- 83 F5.2 arcsec DEs Declination (J2000)
85- 90 F6.3 mag Imag ?=-1.000 Mean of all magnitude values which
could be determined
92- 97 F6.3 mag e_Imag ?=-1.000 Scatter of all magnitudes used
in mean calculation
100-106 F7.1 --- Flux Reference flux
109-113 F5.2 mag mag0 Magnitude zero point
115-119 F5.2 pix Rad Distance between the centroid of the variable
and the nearest DoPhot star in the reference
image (2)
122 I1 --- VType [1/3] Type of variable (3)
125-127 I3 --- NFrames Number of frames used in centroid determination
131 I1 --- NBad Number of bad pixels in the fitting radius on
the reference image
134-136 I3 --- NGood Number of "good" flux measurements. (4)
139-141 I3 --- Nmag Number of magnitude values which could be
determined (5)
143-144 I2 --- Flags [0,31] Composition of flags (6)
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Note (1): 0.0 is the middle of the bottom left pixel.
Note (2): Used for the calculation of the reference flux and
conversion to magnitudes.
Note (3): Type of variable as follows:
1 = "transient"
2 = "continuous variable"
3 = "transient" and "continuous variable"
Note (4): A "good" point is the one for which non of the several types
of problems monitored by the pipeline occurred (flags 1-11 are set
to 0, see below)
Note (5): The ones which are not determined come from non-positive fluxes.
Note (6): Catalog flags are coded as single bits of a 4-byte integer
and listed below (the least significant bit first). This provides a
very efficient way of storing information about up to 32 conditions
that occurred or not by setting 1 or 0 for individual bits of the
binary representation. Integer value 12, e.g., means that flags 3 and
4 are true and the rest are false. For pipeline parameters relevant to
setting the flags we quote their names and actual values used in our
analysis. The flags are (the corresponding factor is in parentheses):
1 (01): crowding flag, set if within ±4 pixels of the maximum pixel
with flux f0 there is a secondary local maximum with pixel flux
f>0.15*f0*r, where r is the distance from the star centroid in
pixels
2 (02): fewer than NFrames=4 used in centroid finding
3 (04): more than NBad=0 bad pixels on the reference image within the
fitting radius of 3.0 pixels
4 (08): fraction of less than MIN_GFRA=0.5 difference flux measurements
are "good" from the total number of frames taken for the field.
A "good" point is the one for which non of the several types of
problems monitored by the pipeline occurred
(flags 1-11 in Appendix B of the paper are set to 0).
5 (16): mean magnitude and its scatter could not be calculated because
fewer than 2 individual magnitudes were defined
Note (7): the full name of a variable is
OGLE BUL-SCff Vnnnn (also called DIA)
where ff is the field number (zero-filled) and nnnn if the
number of the variable in the field.
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History:
Copied at ftp://bulge.princeton.edu/ogle/ogle2/bulge_dia_variables
References:
Wozniak, Paper I 2000AcA....50..421W 2000AcA....50..421W, Cat. J/AcA/50/421
Wozniak et al., Paper II 2001AcA....51..175W 2001AcA....51..175W Cat. J/AcA/51/175
(End) Patricia Vannier [CDS] 16-Jul-2005