J/ApJ/631/906 MACHO Galactic Bulge microlensing events (Thomas+, 2005)
Galactic Bulge microlensing events from the MACHO Collaboration.
Thomas C.L., Griest K., Popowski P., Cook K.H., Drake A.J., Minniti D.,
Myer D.G., Alcock C., Allsman R.A., Alves D.R., Axelrod T.S., Becker A.C.,
Bennett D.P., Freeman K.C., Geha M., Lehner M.J., Marshall S.L.,
Nelson C.A., Peterson B.A., Quinn P.J., Stubbs C.W., Sutherland W.,
Vandehei T., Welch D.L., (the Macho Collaboration)
<Astrophys. J., 631, 906-934 (2005)>
=2005ApJ...631..906T 2005ApJ...631..906T
ADC_Keywords: Surveys ; Stars, variable ; Photometry
Keywords: catalogs - Galaxy: bulge - Galaxy: structure - gravitational lensing -
stars: dwarf novae - stars: variables: other
Abstract:
We present a catalog of 450 relatively high signal-to-noise ratio
microlensing events observed by the MACHO collaboration between 1993
and 1999. The events are distributed throughout our fields, and as
expected, they show a clear concentration toward the Galactic center.
No optical depth is given for this sample, since no blending
efficiency calculation has been performed and we find evidence for
substantial blending. In a companion paper we give optical depths for
the subsample of events on clump giant source stars, where blending is
a less significant effect. Several events with sources that may belong
to the Sagittarius dwarf galaxy are identified. For these events even
relatively low dispersion spectra could suffice to classify these
events as either consistent with Sagittarius membership or as
non-Sagittarius sources. Several unusual events, such as microlensing
of periodic variable source stars, binary lens events, and an event
showing extended source effects, are identified. We also identify a
number of contaminating background events as cataclysmic variable
stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 104 528 Event parameters
table4.dat 101 36 Parameters for non-microlensing events
table5.dat 50 50 Alternative designations of our events
lcurves.dat 314 1272 List of light-curves (header of the files)
lc/* . 1272 Individual B and R light curves
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See also:
J/ApJ/562/337 : High proper-motion stars from MACHO (Alcock+, 2001)
J/AcA/52/129 : DIA OGLE2 candidate variable stars catalog (Wozniak+ 2002)
J/MNRAS/349/1059 : OGLE variables in Galactic bar (Wray+, 2004)
Byte-by-byte Description of file: table3.dat table4.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- MACHO Event name (field.tile.seq)
16- 19 A4 --- Flag Flag on the source identification (2)
21- 22 I2 h RAh Hour of Right Ascension (J2000)
24- 25 I2 min RAm Minute of Right Ascension (J2000)
27- 31 F5.2 s RAs Second of Right Ascention (J2000)
33 A1 --- DE- Sign of the Declination (J2000)
34- 35 I2 deg DEd Degree of Declination (J2000)
37- 38 I2 arcmin DEm Arcminute of Declination (J2000)
40- 44 F5.2 arcsec DEs Arcsecond of Declination (J2000)
45- 49 F5.2 mag Vmag ? The Johnson V band magnitude at the base
51- 55 F5.2 mag V-Rc ? The (V-Rc) color index at the base
57- 62 F6.1 d t0 Time of maximum amplification
64- 69 F6.2 d that Einstein ring diameter crossing time
71- 78 E8.3 --- Amax Maximum amplification
80- 84 F5.2 --- chi2 The reduced chi2
86 A1 --- Grade Subjective grade of event (3)
88- 89 A2 --- Sel Selection criteria (4)
91-102 A12 --- Notes Additional notes (5)
104 A1 --- T5 [*] Indicates a OGLE cross-identification
in table5
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Note (2): The "!" symbol denotes clump giants. Letter superscripts denote
the same event found in multiple objects. For table3, the other event
in the pair may be present in Table 4. For table4, these events are
due to blending of flux from a real event and should be ignored for
any analysis.
Note (3): The grades are on an A-F scale (A=best).
Note (4): Selection criteria are:
c = for our clump-like selection criteria
e = for events found by eye
a = for events found via the alert system
b = for events from the binary paper
Note (5): Additional notes as follows:
bin = suspected binary lensing event
R<>B = Red and blue light curves differ
var = suspected variable star
cv = Likely cataclysmic variable
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- MACHO Event name (field.tile.seq)
17- 31 A15 --- Ogle OGLE designation
34- 50 A17 --- OGLE OGLE name as in Simbad (1)
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Note (1):
DIA BUL_SCNN NNNN designations from Wozniak et al. 2002, Cat. J/AcA/52/129
BUL_SCNN NNNN designations from Udalski et al. 2000AcA....50....1U 2000AcA....50....1U
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Byte-by-byte Description of file: lcurves.dat
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Bytes Format Units Label Explanations
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1- 21 A21 --- FileName Name of the file in subdirectory lc
23 A1 --- Band [rb] Red (r) or blue (b) band
25- 38 A14 --- MACHO Event name (field.tile.seq)
40- 45 F6.3 mag Red (or blue) median magnitude of star in
instrumental magnitudes (1)
47- 48 I2 --- cat Bitmapped analysis code lightcurve
category (2)
50- 56 F7.2 pix Xpos X position
58- 64 F7.2 pix Ypos Y position
66- 74 F9.5 --- Red (or blue) average error in A-1 units
76- 82 F7.5 --- r Robust red (or blue) average error (robust
means removing 10% highest and lowest points)
84- 89 F6.1 d tfilt Time of filter maximum (rough idea of where
lightcurve peaks, in MACHO days)
90- 98 F9.4 --- chi2w Chi2/degree-of-freedom of fit to constant
lightcurve
99-108 E10.9 --- chi2r Robust chi2/dof fit to constant star
110-112 I3 --- nhip Number of 2σ high points under
(triggered) filter area
114-124 F11.6 d that Duration of microlensing fit
(time to cross Einstein ring diameter)
126-133 F8.3 d te Duration of fit microlensing fit
(time above A=1.1)
135-144 E10.4 --- A1max ? Peak A-1 for mlc fit (joint red/blue fit)
146-157 F12.6 d t0 Time of mlc fit peak (JD-2448623.5)
159-166 F8.6 --- A0 Baseline Offset in microlensing fit
168-174 F7.4 --- chi2dof Chi2/dof for microlensing fit to data
(4 fit dof)
177-187 E11.8 --- probfit The log(probability) of getting chi2 above
189-197 E9.4 --- delc2 Difference between microlensing fit chi2 and
chi2 of fit to constant star
200-204 F5.1 --- fnhip Number of 1-sigma high points under fit peak
(i.e. with fit A>1.1)
209-217 F9.5 --- fachrom Logprob of achromaticity under peak
(fit to B-R=0)
219-224 I6 --- befaft Coded number of points before and after fit
peak 1000*(# before peak) + (# after peak)
226-236 F11.6 --- crdrej Fraction of points rejected due to sodophot
crowding measure
238-245 F8.4 --- pchi2 Chi2/dof under fit peak (A>1.1)
247-249 I3 --- pnum Number of points (red +blue) under fit peak
(A>1.1)
251-253 I3 --- pnumf Number of points on falling side of fit
lightcurve (A>1.1)
255-265 E11.7 --- probin log(prob) of chi2 of mlc fit for points
within 4 that of peak
267-277 E11.7 --- probout log(prob) of chi2 of mlc fit for points
farther than 4 that of peak
279-285 F7.3 deg RAdeg Right ascension in decimal degrees (J2000)
287-294 F8.4 deg DEdeg Declination in decimal degrees (J2000)
296-303 I8 --- version [20020430] Date of version of analysis code:
year-month-day
305-312 F8.5 --- magcor Correction to red (or blue) median magnitude:
use to find original sodophot magnitude
before bad observations were removed.
314 I1 --- icalib Not used
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Note (1):
Kron-Cousins' R band is approximately given by:
Rmag = b-0.18(b-r)+23.70
Johnson's V band is approximately given by:
Vmag = r+0.18(b-r)+23.41
where r and b are the instrumental magnitudes used in these files
Note (2): bitmapped analysis code lightcurve category:
≥10 level 1 microlensing,
≥20 level 1.5 microlensing,
≥30 level 2 microlensing:
one's place bitmap:
001 = passes standard variable search,
010 = eclipsing binary search,
86 = passes correlation variable search
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Byte-by-byte Description of file (#): lc/*
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Bytes Format Units Label Explanations
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3- 11 F9.4 d Time Date in MACHO days from
JD=2448623.5 (Jan 2, 1992)
14- 28 F15.10 --- A-1 ?=-99. A-1 (NOT magnitude!)
((flux/(median flux)) -1)
32- 43 F12.8 --- eA-1 ?=-99. Error in A-1 (NOT magnitude)
46- 50 I5 --- obsid MACHO observation number
53- 59 F7.3 pix seeing Seeing (1pix=0.63arcsec)
61- 69 E9.4 --- sky Coded value fit sky
74- 78 F5.3 --- airmass Airmass
81- 83 I3 --- version [-99] Version (not used)
86- 88 I3 --- type ?=-99 Encoded dophot photometry type (1)
90- 93 I4 --- dsky Coded version of
(sky-)/(template amplitude)
96- 98 I3 --- psfc2 ?=-99 Coded version of chi2 of fit to
point spread function
101-103 I3 --- crd ?=-99 Coded crowding flag
106-108 I3 --- cosm ?=-99 Coded cosmic ray hit flag
111-113 I3 --- miss ?=-99 Coded number of missing pixels in PSF
118 I1 --- pier [0/1] observation with telescope west (0)
or east (1) of pier
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Note (1): Encoded dophot photometry type:
1 = bright unsplit star, 9 = unconverged
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 25-Aug-2006