microlensing photometry

June 1 2022. 

ATLAS covers sky to 19.5 at 5 sigma. That's an uncertainty of 20% or 0.2 mag. The all-sky, nightly coverage from multiple sites makes this an excellent resource for microlensing. 

Microlensing surveys: 
OGLE, Las Campanas in Chile, has been shut down for years due to COVID
MOA in New Zealand 
KMTNET has telescopes in Chile, South Africa, Australia. 

Web sites with microlensing events (note the anomalous ones are arguably the most interesting)

MOA: http://www.massey.ac.nz/~iabond/moa/alert2022/alert.php 
KMTNET: https://kmtnet.kasi.re.kr/ulens/.   and https://kmtnet.kasi.re.kr/ulens/event/2022/ 
OGLE: http://ogle.astrouw.edu.pl/ogle4/ews/ews.html  

Galactic bulge reanalysis and compendium from OGLE: https://aasnova.org/2022/05/20/a-massive-reanalysis-of-microlensing-events/

MOA anomaly events http://iral2.ess.sci.osaka-u.ac.jp/~moa/anomaly/ 

ATLAS forced photometry server: https://fallingstar-data.com/forcedphot/ 

Some examples: 

KMT-2022-BLG-0061, difference request

JT says 2022 observations from Chile aren't in the forced photometry data, and that the Hawaii telescope stayed in the N after early calendar 2022. So need to look back into previous years. 

Brighter ones do better:

Converting to magnitudes, for the more pedestrian among us: 

m_AB=-2.5log10(Jy) + 8.90. 

ATLAS started operation mid-2015, so it's appropriate to compile a list of events from calendar 2015 to 2022. That spans both OGLE (until 2020) and MOA, not sure about KMT. 

MOA to OGLE correspondences: https://www.massey.ac.nz/~iabond/moa/alert2016/moa2ogle.php

MKTnet telescopes go fainter. Use their event catalogs from online data set. 

text file columns: 

name,  DiscoveryField,  Class(1=clear, 2=probable), RA, DEC, MJDcenter, duration (days), impact parameter ~ 1/Amplification, Iband1, Iband2, Iband3, Ctype (??), Amplification, other names

Tasks: 

1) construct aggregated event list that spans years when ATLAS observed Galactic plane.

                                        DONE- had to clean up changes in data format between years, for KMT alert files, and delete a few incomplete records. KMTevents.txt has around 15,000 candidate bulge events.

                                        event file sorted from bright to faint: KMTeventsSorted.txt 

2) for each event, do a query on forced photometry difference photometry for duration spanning 10 event duration times on either side of event center.
3) construct database of event photometry.  We should extract both regular and difference image forced photometry. 

Things we can do: 1) fill in gaps from Chile and S Africa
                                2) use multi-band data to plot c vs. o fluxes, investigate blending and chromaticity. 
                                3) added information for anomalous events, temporal coverage. 

stress in paper-

MJD coverage, esp for planets. example is MOA-2019-BLG-055 / OGLE-2019-BLG-0109. planet excursion. No planet indication in OGLE data, but it is there in MOA data. 

blue is ATLAS, red is MOA, orange is OGLE

public server for photometry

CWS notes from Paris 2022 microlensing meeting

schedule is https://bit.ly/ulens25-schedule

planetary excursion of short duration, perhaps in halo, AT2021uey Makiko Ben 

xallarap example is OGLE-2017-BLG-0114

another xallarap example is OGLE-2019-BLG-0825, 5.5 day period xallarap

See P. Rota et al 2021 for xallrap example,  

K2-2016-BLG-0001

Roman launch Sept 2026 is current best-guess

0.1 arcsec pixels, 8 filters, 0.43 to 2.4 microns. 

Need to connect with Rachael Street about Omega project and all-sky microlensing

GAIA ends 2025, to 20.5 mag

one mas at 18th for DR3

GAIA 20 FNR is interetsing event

Gaia Microlensing data:

363 events from https://arxiv.org/abs/2206.06121, used the Ex. 1 query in appendix B (which downloads the entire catalog) at https://gea.esac.esa.int/archive/

Note: used the event duration from the level 0 fit as the event duration (paczynski0_te).

also downloaded planet excursion RA Dec: 324.545 26.46656 for event AT2021uey (below is the plot of the data):

Quality Cuts and Compilation of Sources

Overall, for KMT events 15434 sources out of 15689 in the text file KMTeventsSorted.txt.

For Gaia events 286 sources out of 363 sources in the arXiv were found (77 had no data to download).

Additionally, we have AT2021uey, reported by Makiko Ban • Astronomical25
Observatory, University of Warsaw at Paris ulensing workshop

This gives a total of 15721 light curves (although I need to request AT2021uey over a wider range of dates).

As far as overlapping sources go, 72 of the 363 Gaia sources have a KMT event within 2 arcsec and with a peak within 100 days of the Gaia peak, meaning they are presumably the same source (although interestingly 3 of these have two KMT events that match. Also, if we instead look within 3 tau of the Gaia event duration we have 77 sources matching KMT events (and four sources matching two KMT events)). However, the difference of a couple arcsec can lead to differences of 0.5 mag (need to quantify this more).

All Gaia and KMT events were uploaded to /n/stubbs_lab/Lab/Microlensing/ATLAS_events_cuts and then there was an extra column added, 0 for a bad point, 1 for a good point, with the cut being:

1. $\sigma_{ABmag}<$0.5, 
2. PSF-fit $\chi^2/DOF <$3.0,
3. Sky $>$ 15 mag per sq arc sec.

The relevant notebook used to do this is in /n/stubbs_lab/Users/eurbach.

Not sure how to deal with the overlapping sources between Gaia and KMT (they also have slightly different peak durations and dates) and also I am looking at error more generally by looking at light curves offset by 20 arcsec in RA.

However, very few events have many good points with SNR > 5 within 3 tau of center. Of the 286 Gaia curves, 62 have more than one point of SNR > 5 within 3 tau of center, and 32 have more than five points with SNR > 5 within 5 tau of center. 161 have at least one 'good' point within 3 tau of center, and 125 have at least 5 good points within 3 tau of center.

For the KMT events, there are 2101 events with one point with SNR > 5 within 3 tau of center and 896 events with more than five points with SNR > 5 within 3 tau of center. 13062 have at least one 'good' point within 3 tau of center, and 10037 have at least 5 good points within 3 tau of center.

We have decided to use the cutoff for inclusion as 3 good events within 3t of center. There are 12213 in KMT and 154 in Gaia + AT2021uey is 12368 events.

Of those, for Gaia: 88 events have 1+ points with SNR > 5, 44 have 3 or more points with SNR > 5

for KMT,  3411 events have 1+ points with SNR > 5, 1576 have 3 or more points with SNR > 5

Questions to answer:

1. How many good points (and/or points with high SNR) are needed to include in the database?