J/ApJS/216/12 OGLE-III Galactic bulge microlensing events (Wyrzykowski+, 2015)
OGLE-III microlensing events and the structure of the Galactic bulge.
Wyrzykowski L., Rynkiewicz A.E., Skowron J., Kozlowski S., Udalski A.,
Szymanski M.K., Kubiak M., Soszynski I., Pietrzynski G., Poleski R.,
Pietrukowicz P., Pawlak M.
<Astrophys. J. Suppl. Ser., 216, 12 (2015)>
=2015ApJS..216...12W 2015ApJS..216...12W
ADC_Keywords: Gravitational lensing ; Milky Way
Keywords: catalogs; Galaxy: bulge; Galaxy: structure;
gravitational lensing: micro
Abstract:
We present and study the largest and most comprehensive catalog of
microlensing events ever constructed. The sample of standard
microlensing events comprises 3718 unique events from 2001-2009 with
1409 events that had not been detected before in real-time by the
Early Warning System of the Optical Gravitational Lensing Experiment.
The search pipeline uses machine learning algorithms to help find rare
phenomena among 150 million objects and to derive the detection
efficiency. Applications of the catalog can be numerous, from
analyzing individual events to large statistical studies of the
Galactic mass, kinematics distributions, and planetary abundances. We
derive maps of the mean Einstein ring crossing time of events spanning
31 deg2 toward the Galactic center and compare the observed
distributions with the most recent models. We find good agreement
within the observed region and we see the signature of the tilt of the
bar in the microlensing data. However, the asymmetry of the mean
timescales seems to rise more steeply than predicted, indicating
either a somewhat different orientation of the bar or a larger bar
width. The map of events with sources in the Galactic bulge shows a
dependence of the mean timescale on the Galactic latitude, signaling
an increasing contribution from disk lenses closer to the plane
relative to the height of the disk. Our data present a perfect set for
comparing and enhancing new models of the central parts of the Milky
Way and creating a three-dimensional picture of the Galaxy.
Description:
The data used in this work were photometry of 150 million objects
toward more than 31deg2 of the Galactic bulge observed in almost
74000 frames, i.e., about 11000 billion data points. We selected 91
fields out of all 177 ever observed by the Optical Gravitational
Lensing Experiment (OGLE) Udalski et al. (2008AcA....58...69U 2008AcA....58...69U) in its
third phase from 2001 July until 2009 May, which had at least 250
observations. We use the re-reduced data obtained after the end of
OGLE-III. For the final sample of microlensing events, we additionally
produced new photometry which took into account the exact position of
each event on the difference imaging technique (DIA, Wozniak 2000,
J/AcA/50/421) image (see section 2).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 86 3560 OGLE-III standard events of class A
table2.dat 263 3560 Markov Chain Monte-Carlo (MCMC) microlensing
parameters for 3560 standard OGLE-III microlensing
events of class A
table3.dat 71 158 *OGLE-III candidate standard events (class B)
table4.dat 27 36 Mean Time-scale Bins for OGLE-III Events
--------------------------------------------------------------------------------
Note on table3.dat: Apart from the fully automatized search procedure for
finding microlensing events, we also applied a separate search for standard
events for which the full blended fit was not converging, i.e., when the
minimalization procedure was not finding any solutions or was returning
unphysical values for parameters, and events rejected during other stages of
constructing of class A. From a sample of light curves rejected at the
prefiltering stage, we selected those for which χ2µ4/dof the for
the non-blended model was smaller than 2.5 if the baseline was fainter than
16mag, and χ2µ4/dof<5 for I0µ4<16. To ensure that only
high-quality events passed through that filter, we also required that the peak
be covered with at least 10 data points and selected only those events with
significant amplification, i.e., with I0µ4<1 in the non-blended model.
There were about 300 candidates that were then visually inspected, and an
additional sample of 158 "class B" standard events was selected.
--------------------------------------------------------------------------------
See also:
J/AcA/63/21 : VI light curves of Galactic LPVs (Soszynski+, 2013)
J/other/Nat/481.167 : 2002-2007 PLANET microlensing events (Assan+, 2012)
J/ApJ/711/L48 : 2008 OGLE Bulge microlensing alerts (Cohen+, 2010)
J/A+A/475/1159 : Supervised classification of var. stars (Debosscher+, 2007)
J/A+A/466/157 : Bulge Microlensing Events (Soto+, 2007)
J/A+A/454/185 : EROS-2 microlensing parameters (Hamadache+, 2006)
J/ApJ/636/240 : OGLE II microlensing parameters (Sumi+, 2006)
J/ApJ/631/906 : MACHO Galactic Bulge microlensing events (Thomas+, 2005)
J/MNRAS/343/1131 : 1998-2000 OGLE events microlensing limits (Tsapras+, 2003)
J/AcA/53/1 : OGLE eclipsing binaries in LMC (Wyrzykowski+, 2003)
J/AcA/52/217 : OGLE II. VI photometry of Galactic Bulge (Udalski+, 2002)
J/AcA/51/175 : OGLE-II DIA microlensing events (Wozniak+, 2001)
J/AcA/50/421 : OGLE-II DIA BUL_SC1 field (Wozniak, 2000)
J/AcA/50/1 : OGLE microlensing events in Galactic Bulge (Udalski+, 2000)
http://ogle.astrouw.edu.pl/ : OGLE home page
ftp://ftp.astrouw.edu.pl/ogle/ogle3/blg_tau/ : OGLE-III Galactic Bulge
Microlensing Events archive data
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Seq [1/3560] OGLE identifier; OGLEIII standard
microlensing events (ULENS)
6- 7 I2 h RAh [17/18] Hour of Right Ascension (J2000)
9- 10 I2 min RAm Minute of Right Ascension (J2000)
12- 16 F5.2 s RAs Second of Right Ascension (J2000)
18 A1 --- DE- [-] Sign of the Declination (J2000)
19- 20 I2 deg DEd [22/36] Degree of Declination (J2000)
22- 23 I2 arcmin DEm Arcminute of Declination (J2000)
25- 28 F4.1 arcsec DEs Arcsecond of Declination (J2000)
30- 32 A3 --- --- [BLG]
33- 37 F5.1 --- Field [100.1/354.4] Field identifier
39- 44 I6 --- Star [28/302120] Star number
46- 70 A25 --- EWS Early Warning System identifier (YYYY-BLG-NNN)
72- 86 A15 --- Dup Duplicate identifier (BLGFFF.F.NNNNNN)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Seq [1/3560] OGLE identifier; OGLEIII-ULENS-
6- 7 I2 h RAh [17/18] Hour of Right Ascension (J2000)
9- 10 I2 min RAm Minute of Right Ascension (J2000)
12- 16 F5.2 s RAs Second of Right Ascension (J2000)
18- 18 A1 --- DE- [-] Sign of the Declination (J2000)
19- 20 I2 deg DEd [22/36] Degree of Declination (J2000)
22- 23 I2 arcmin DEm Arcminute of Declination (J2000)
25- 28 F4.1 arcsec DEs Arcsecond of Declination (J2000)
30- 44 A15 --- OGLE The field-starno identifier (BLGFFF.F.NNNNNN;
in Simbad)
46- 56 F11.6 d t0 Heliocentric Julian Date of time of
peak maximum (HJD-2450000)
58- 65 F8.6 d e_t0 Lower uncertainty in t0
67- 74 F8.6 d E_t0 Upper uncertainty in t0
76- 85 F10.6 d tE [1.4/393.2] Einstein radius crossing time
87- 96 F10.6 d e_tE Lower uncertainty in tE
98-107 F10.6 d E_tE Upper uncertainty in tE
109-116 F8.6 --- mu0 [0/1.7] Impact parameter
118-125 F8.6 --- e_mu0 Lower uncertainty in mu0
127-134 F8.6 --- E_mu0 Upper uncertainty in mu0
136-143 F8.6 --- fS [0.001/1.8] Blending fraction (ratio of lensed
source flux to total blends' flux in the I band)
145-152 F8.6 --- e_fS Lower uncertainty in fS
154-161 F8.6 --- E_fS Upper uncertainty in fS
163-171 F9.6 mag Imag [13.1/20.8] The I band baseline magnitude
173-180 F8.6 mag e_Imag Lower uncertainty in Imag
182-189 F8.6 mag E_Imag Upper uncertainty in Imag
191-203 F13.6 --- chi2 [120/342360] The χ2 fit
205-208 I4 --- DoF [96/2535] Number of degrees of freedom
210-215 F6.3 mag Vmag [14.3/22.6]?=99.999 The V band magnitude
217-221 F5.3 mag e_Vmag [0.001/2.3]?=9.999 Uncertainty in Vmag
223-247 A25 --- EWS Early Warning System identifier (YYYY-BLG-NNN)
249-263 A15 --- Dup Duplicate identifier (BLGFFF.F.NNNNNN)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- ID [90001/90158] OGLE identifier; OGLEIII-ULENS-
7- 8 I2 h RAh [17/18] Hour of Right Ascension (J2000)
10- 11 I2 min RAm Minute of Right Ascension (J2000)
13- 17 F5.2 s RAs Second of Right Ascension (J2000)
19 A1 --- DE- [-] Sign of the Declination (J2000)
20- 21 I2 deg DEd [22/36] Degree of Declination (J2000)
23- 24 I2 arcmin DEm Arcminute of Declination (J2000)
26- 29 F4.1 arcsec DEs Arcsecond of Declination (J2000)
31- 38 A8 --- Field Field identifier (BLGFFF.F)
40- 45 I6 --- Star [3390/261307] Star number
47- 71 A25 --- EWS Early Warning System identifier (YYYY-BLG-NNN)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 F4.1 deg lbin Central galactic longitude bin
6- 9 F4.1 deg bbin Central galactic latitude bin
11- 14 F4.1 d <tE> [15.6/47.1] Mean Einstein radius crossing time
16- 19 F4.1 d <tE>c Efficiency corrected mean Einstein radius
crossing time
21- 24 F4.1 d <tE>G Gaussian smoothed mean Einstein ring crossing
time
26- 27 I2 --- Nev [6/98] Number of events
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 12-Feb-2015