OGLE-2 EARLY WARNING SYSTEM - 2000 EVENTS

The Early Warning System (EWS) was designed for detection of microlensing events in progress and successfully implemented during the first phase of the OGLE experiment. During 1994 and 1995 observing seasons, this system detected 8 events.

Starting May 6th, 1998, the EWS system is reimplemented for the second phase of the experiment, called OGLE-2, which is carried out using 1.3 m Warsaw Telescope at Las Campanas Observatory, Chile.

PLEASE NOTE that the OGLE-II phase ended on November 26, 2000. Observations will be resumed in early 2001 with a new mosaic CCD camera. EWS system will be reimplemented some time later.

About 30 million stars were monitored in the Galactic bulge each night. Expected rate of microlensing events is about 50 per observing season (based on preliminary results of 1997 season). Several million stars are also monitored in fields covering most of the Large and Small Magellanic Clouds, as well as in some additional fields in the Galactic disk. These fields are also subject to real time microlensing search.

The Early Warning System is fully described in Udalski et al., 1994, Acta Astron., 44, 227. In short, an alarm is triggered if a star from the constant objects database (built from previous seasons data) brightens above 3-sigma level from its base magnitude for 4 consecutive observations. Sigma levels are computed for the whole sample of stars (as a function of mean magnitude) to define which objects are constant. When such a star is found, its light curve is inspected by eye, its position on the recent CCD frames checked for bad pixels, bleeding columns etc. and if it passes these checks, it is announced as a microlensing candidate.

EWS has detected 78 candidate microlensing events in the 2000 observing season. The table given below provides interactive WWW access to the finding charts, photometry data and other information about all events. Currently ongoing events are marked with . Particularly interesting events are marked with . Events detected in the previous season(s) can also be found: 41 events in 1998, 48 events in 1999.

Microlensing events data can also be found on Anonymous FTP.

There is also a mailing list providing on-line notification on the detected events. Astronomers interested in follow-up observations and willing to receive e-mail notification, should fill out subscribe/unsubscribe form. If you have any questions or comments, send us a message.

The following table contains basic parameters of the candidate events as well as the links to the WWW pages with finding charts, light curve plots and photometric data. Photometry in Galactic bulge fields is based on preliminary absolute calibration and is accurate to about 0.05 mag. It will be refined in the near future. Microlensing light curve model fit parameters have following meaning:


EventFieldStar NoRA (J2000)Dec (J2000) Tmax (HJD) Tmax (UT) tau Amax Dmag I0
2000-BUL-01 BUL_SC27 417748 17:48:28.86 -35:18:35.3 2451585.643 2000-02-11.14 13.980 5.097 1.768 18.477
2000-BUL-02 BUL_SC5 152125 17:50:13.30 -29:49:57.6 2451566.234 2000-01-22.73 83.321 1.958 0.729 15.075
2000-BUL-03 BUL_SC43 272803 17:35:16.42 -27:18:40.5 2451581.868 2000-02-07.37 62.973 1.852 0.669 17.563
2000-BUL-04 BUL_SC5 348855 17:50:51.07 -30:10:22.2 2451581.467 2000-02-06.97 28.123 1.362 0.335 14.990
2000-SCO-01 SCO_SC7 38447 17:03:05.58 -44:21:23.8 2451491.653 1999-11-09.15 88.623 2006.3 8.256 16.890
2000-BUL-05 BUL_SC33 540825 18:05:45.79 -28:30:52.4 2451552.902 2000-01-09.40 57.926 2.759 1.102 15.215
2000-BUL-06 BUL_SC22 77397 17:56:26.85 -30:54:27.4 2451620.938 2000-03-17.44 22.756 32.448 3.778 17.195
2000-BUL-07 BUL_SC4 321697 17:54:25.13 -29:37:49.4 2451615.292 2000-03-11.79 25.366 1.880 0.685 16.762
2000-LMC-01 LMC_SC9 4007 5:12:44.91 -69:41:28.1 2451603.828 2000-02-29.33 45.246 4.114 1.536 20.503
2000-BUL-08 BUL_SC15 362747 17:48:09.57 -23:14:00.2 2451625.050 2000-03-21.55 49.099 1.450 0.404 15.706
2000-SCO-02 SCO_SC1 131946 16:41:02.61 -44:36:02.5 2451702.030 2000-06-06.53 16.356 4.657 1.670 18.745
2000-BUL-09 BUL_SC21 166607 18:00:00.22 -28:38:18.3 2451614.779 2000-03-11.28 16.568 2.088 0.799 17.864
2000-BUL-10 BUL_SC34 451887 17:58:14.20 -28:48:22.3 2451580.552 2000-02-06.05 54.537 1.878 0.684 15.918
2000-BUL-11 BUL_SC43 357654 17:35:37.97 -27:37:14.6 2451616.062 2000-03-12.56 8.413 3.772 1.441 17.741
2000-BUL-12 BUL_SC43 244614 17:35:13.40 -27:35:18.7 2451635.963 2000-04-01.46 25.569 50.678 4.262 18.875
2000-BUL-13 BUL_SC37 401293 17:52:32.30 -29:58:46.8 2451654.364 2000-04-19.86 47.379 1.198 0.196 15.344
2000-BUL-14 BUL_SC3 91894 17:53:08.92 -29:59:02.6 2451630.075 2000-03-26.57 27.855 1.317 0.299 16.972
2000-BUL-15 BUL_SC40 443839 17:51:11.19 -33:00:57.0 2451630.712 2000-03-27.21 5.457 2.398 0.950 15.202
2000-BUL-16 BUL_SC24 145952 17:52:46.03 -32:30:23.8 2451632.039 2000-03-28.54 23.310 7.383 2.171 18.437
2000-BUL-17 BUL_SC5 230720 17:50:27.62 -30:09:29.9 2451648.932 2000-04-14.43 22.905 5.357 1.822 16.666
2000-BUL-18 BUL_SC24 233671 17:53:15.27 -32:55:35.0 2451634.760 2000-03-31.26 3.857 1.818 0.649 18.999
2000-BUL-19 BUL_SC41 308026 17:52:16.43 -33:33:58.9 2451652.438 2000-04-17.94 42.129 2.778 1.109 18.802
2000-BUL-20 BUL_SC30 289030 18:01:24.97 -28:50:41.4 2451647.327 2000-04-12.83 25.860 3.173 1.254 17.967
2000-BUL-21 BUL_SC2 423881 18:04:26.00 -28:26:31.4 2451655.508 2000-04-21.01 20.955 4.270 1.576 19.160
2000-BUL-22 BUL_SC19 47385 18:07:41.84 -27:28:25.7 2451668.036 2000-05-03.54 107.329 4.373 1.602 19.915
2000-BUL-23 BUL_SC24 435701 17:53:33.27 -32:33:29.1 2451665.599 2000-05-01.10 8.626 3.123 1.237 18.919
2000-BUL-24 BUL_SC27 554610 17:48:49.20 -35:25:28.5 2451683.554 2000-05-19.05 22.708 1.248 0.241 14.203
2000-BUL-25 BUL_SC37 645044 17:52:58.69 -29:34:22.2 2451685.691 2000-05-21.19 13.399 3.331 1.306 16.449
2000-BUL-26 BUL_SC3 478487 17:53:47.38 -30:05:26.2 2451705.657 2000-06-10.16 33.731 1.594 0.506 14.045
2000-BUL-27 BUL_SC4 274100 17:54:26.55 -29:51:05.7 2451681.489 2000-05-16.99 14.472 3.819 1.455 18.557
2000-BUL-28 BUL_SC34 358528 17:58:13.12 -29:09:14.3 2451678.314 2000-05-13.81 8.541 6132.3 9.469 16.977
2000-BUL-29 BUL_SC37 463341 17:52:44.65 -29:39:57.0 2451698.297 2000-06-02.80 19.739 3.708 1.423 17.067
2000-BUL-30 BUL_SC30 454605 18:01:30.89 -28:59:26.7 2451780.789 2000-08-24.29 65.706 1.638 0.536 15.572
2000-BUL-31 BUL_SC12 430062 18:16:33.27 -24:14:22.7 2451743.240 2000-07-17.74 28.227 7.637 2.207 15.498
2000-BUL-32 BUL_SC14 73292 17:46:37.46 -23:08:57.8 2451725.975 2000-06-30.48 55.005 1.127 0.130 16.490
2000-BUL-33 BUL_SC17 597331 18:11:28.29 -26:15:05.8 2451730.172 2000-07-04.67 36.774 6.975 2.109 16.991
2000-BUL-34 BUL_SC43 384214 17:35:36.03 -27:23:18.1 2451710.771 2000-06-15.27 15.495 3.520 1.366 17.762
2000-BUL-35 BUL_SC41 467827 17:52:24.55 -33:30:04.3 2451702.910 2000-06-07.41 8.907 75.181 4.690 18.469
2000-BUL-36 BUL_SC20 371199 17:59:08.14 -28:32:57.0 2451712.371 2000-06-16.87 23.629 1.135 0.137 16.067
2000-BUL-37 BUL_SC14 235123 17:47:00.44 -23:09:48.7 2451714.101 2000-06-18.60 13.317 1.693 0.572 17.633
2000-BUL-38 BUL_SC3 318561 17:53:19.20 -29:57:33.9 2451716.200 2000-06-20.70 - - - 17.870
2000-BUL-39 BUL_SC22 371120 17:56:43.74 -30:22:23.7 2451719.628 2000-06-24.13 13.365 1.312 0.295 17.099
2000-BUL-40 BUL_SC17 404893 18:11:12.40 -26:24:10.3 2451785.386 2000-08-28.89 57.705 1.876 0.683 16.542
2000-BUL-41 BUL_SC4 65601 17:54:09.41 -29:53:36.9 2451767.256 2000-08-10.76 26.467 1.910 0.703 13.897
2000-BUL-42 BUL_SC31 111306 18:01:52.14 -28:32:36.5 2451749.183 2000-07-23.68 41.472 1.227 0.222 13.540
2000-BUL-43 BUL_SC7 20290 18:08:43.04 -32:24:39.5 2451898.843 2000-12-20.34 173.611 27493.9 11.098 13.752
2000-BUL-44 BUL_SC19 656772 18:08:18.42 -27:07:16.2 2451745.711 2000-07-20.21 35.096 1.481 0.426 17.968
2000-BUL-45 BUL_SC7 68991 18:08:46.39 -32:03:00.8 2451771.488 2000-08-14.99 67.315 5.024 1.753 19.199
2000-BUL-46 BUL_SC4 746833 17:54:55.36 -29:24:59.8 2451750.626 2000-07-25.13 - - - 17.951
2000-BUL-47 BUL_SC4 489287 17:54:42.92 -29:44:12.1 2451751.267 2000-07-25.77 7.888 1.209 0.206 16.329
2000-BUL-48 BUL_SC30 636963 18:01:44.80 -28:58:03.5 2451775.713 2000-08-19.21 18.853 2.970 1.182 15.764
2000-BUL-49 BUL_SC20 274481 17:59:17.80 -29:02:51.4 2451751.456 2000-07-25.96 14.799 1.533 0.464 17.770
2000-BUL-50 BUL_SC33 257733 18:05:28.41 -29:00:46.2 2451774.396 2000-08-17.90 20.728 1.340 0.318 15.827
2000-BUL-51 BUL_SC3 457322 17:53:41.85 -30:15:22.3 2451762.731 2000-08-06.23 18.823 1.513 0.450 17.479
2000-BUL-52 BUL_SC39 338829 17:55:26.64 -29:37:55.9 2451752.887 2000-07-27.39 2.742 2.979 1.185 17.690
2000-BUL-53 BUL_SC28 187954 17:47:01.60 -36:47:58.5 2451759.248 2000-08-02.75 14.190 1.850 0.668 19.080
2000-BUL-54 BUL_SC41 410758 17:52:19.27 -32:57:04.8 2451767.330 2000-08-10.83 25.852 3.516 1.365 18.451
2000-BUL-55 BUL_SC30 94465 18:01:06.71 -28:52:22.6 2451783.789 2000-08-27.29 29.468 27.894 3.614 18.416
2000-BUL-56 BUL_SC35 286520 18:04:12.66 -28:01:08.4 2451785.606 2000-08-29.11 16.378 3.110 1.232 18.136
2000-BUL-57 BUL_SC40 576815 17:51:27.25 -33:06:58.4 2451775.601 2000-08-19.10 5.598 6.570 2.044 18.881
2000-BUL-58 BUL_SC43 243111 17:35:28.91 -27:34:08.7 2451775.378 2000-08-18.88 2.540 1.943 0.721 16.683
2000-BUL-59 BUL_SC21 234352 17:59:54.38 -28:25:47.2 2451779.728 2000-08-23.23 14.346 11.045 2.608 19.429
2000-BUL-60 BUL_SC22 414328 17:56:59.20 -31:03:22.3 2451832.700 2000-10-15.20 39.467 1.568 0.488 16.395
2000-BUL-61 BUL_SC33 290665 18:05:29.67 -28:51:03.3 2451858.909 2000-11-10.41 71.212 1.292 0.278 15.938
2000-BUL-62 BUL_SC30 478797 18:01:26.82 -28:52:34.9 2451799.727 2000-09-12.23 21.142 1.297 0.282 15.554
2000-BUL-63 BUL_SC41 251743 17:51:53.89 -32:59:10.8 2451808.323 2000-09-20.82 17.738 1.552 0.477 17.263
2000-BUL-64 BUL_SC32 702134 18:03:54.71 -28:34:58.8 2451795.910 2000-09-08.41 14.750 6.858 2.091 17.502
2000-BUL-65 BUL_SC39 448311 17:55:44.55 -30:05:19.6 2451838.711 2000-10-21.21 33.877 1.494 0.436 15.212
2000-BUL-66 BUL_SC4 245463 17:54:30.06 -29:57:59.2 2451806.649 2000-09-19.15 28.139 1.391 0.358 17.391
2000-BUL-67 BUL_SC39 1073 17:55:10.06 -30:10:29.5 2451808.289 2000-09-20.79 10.560 1.395 0.361 16.342
2000-BUL-68 BUL_SC34 908441 17:58:43.03 -28:50:17.2 2451811.147 2000-09-23.65 3.617 2.852 1.138 18.195
2000-BUL-69 BUL_SC14 386574 17:47:05.90 -23:09:57.2 2451820.862 2000-10-03.36 16.474 1.189 0.188 16.201
2000-BUL-70 BUL_SC24 522165 17:53:36.61 -32:59:28.9 2451814.533 2000-09-27.03 16.591 2.349 0.927 19.104
2000-BUL-71 BUL_SC19 537362 18:08:09.30 -26:49:12.5 2451844.562 2000-10-27.06 63.811 1.331 0.311 16.075
2000-BUL-72 BUL_SC40 565371 17:51:25.94 -33:09:29.2 2451826.736 2000-10-09.24 15.830 1.800 0.638 17.523
2000-BUL-73 BUL_SC3 166539 17:53:04.21 -29:43:35.2 2451830.083 2000-10-12.58 13.025 4.109 1.534 18.330
2000-BUL-74 BUL_SC31 737372 18:02:53.30 -28:23:18.3 2451836.080 2000-10-18.58 47.726 44.796 4.128 19.026
2000-BUL-75 BUL_SC23 455191 17:57:57.16 -31:16:43.2 2451862.095 2000-11-13.60 47.318 3.471 1.351 18.176

PLEASE NOTE that the OGLE-II phase ended on November 26, 2000. Observations will be resumed in early 2001 with a new mosaic CCD camera. EWS system will be reimplemented some time later.

Andrzej Udalski and Michal Szymanski

Warsaw University Observatory

Warsaw, Poland

Last updated on Wed Dec 20 09:04:05 MET 2000