ASTROMETRIC MICROLENSING WITH GAIA
Łukasz Wyrzykowski (pron: Woo-cash Vi-zhi-kov-ski) Warsaw University Astronomical Observatory, Poland
Sagan Workshop, Pasadena, 10 August 2017 COLLABORATORS here Krzysztof Rybicki (PhD student) here Kasia Kruszyńska (PhD student)
Mariusz Gromadzki (postdoc)
Zuzanna Kostrzewa-Rutkowska (postdoc at SRON, NL) Alex Hamanowicz (Master student -> PhD @ ESO) Gaia Alerts team in Cambridge (UK) MICROLENSING •Gravitational lensing by compact lenses (stellar or remnants) •Mass range from Earth-like to ~100 MSun •Sources: background stars (chance: 10-6 in the Bulge, 10-8 in the LMC)
photometry (sum of images) astrometry (centroid motion)
~1 month ~1mas animationsbyS.Gaudi http://www.astronomy.ohio-state.edu/~gaudi/movies.html BLACK HOLES MICROLENSING •About 0.8% of microlensing events should be due to Black Holes! (Gould 2000) •2000 events found every year -> ~16 black holes every year!! •so, where are they?
high amplification events/finite source (rare)
✓E astrometry M = (VLT/AO, HST, Gaia) ⇡E
Earth parallax
space-based parallax (e.g., Earth-Spitzer) GAIA SPACE MISSION
19 DEC 2013 9:12 UT
GAIA FOCAL PLANE Gaia focalGAIA plane FOCAL(106 CCDs) PLANE Gaia focal plane (106 CCDs) detection astrometric photometry radial velocity and FOV measurements (dispersed (dispersed discriminationdetection astrometric photometryimages) images)radial velocity
and FOV measurements (dispersed (dispersed
discrimination images) images) AF5 AF6 RP RVS1 AF1 AF2 AF3 AF8 AF9 RVS2 RVS3
SM1 AF4 AF7
SM2 BP
AF5 AF6 RP RVS1 AF1 AF2 AF3 AF8 AF9 RVS2 RVS3 SM1 AF4 AF7 SM2 BP Camera:
0.75 deg2
WFS2
pixel size:
10x30 µm
WFS2 star <20 mag WFS1 0.42 m (59x177 mas) detected! Place window. WFS1 0.42 m AC BAM2
AC BAM1 BAM2 AL
BAM1 0.93 m AL Animation by BAM = basic angle monitor, WFS = wavefront sensor Berry Holl, Geneva 0.93 m windowsBAM = basic angle monitor, WFS = wavefront sensor observed: ~4.4 sec ~45 sec GAIA SKY SCANNING PATTERN
figure curtesy: Berry Holl, Geneva HOW TO FIND BLACK HOLES?
http://ogle.astrouw.edu.pl Gaia Science Alerts http://gsaweb.ast.cam.ac.uk/alerts
ESA space mission with 2x1.4m telescopes located in L2. Polish 1.3m dedicated telescope In operation since 2014. in Las Campanas, Chile Surveying continuously since 1992. OGLE-GAIA SKY
Number of Gaia observations after 5 years Gaia figure by Nadia Blagorodnova, OGLE fields by fields Jan Skowron OGLE by Blagorodnova, Nadia Gaia figure STELLAR-MASS BLACK HOLES OGLE3-ULENS-PAR-02 - candidate ~9MSun BH
OGLE photometry
probability distribution OGLE photometry for the proper motion from 2001-2008 based on observed PM and microlensing model
Mass, Distance estimate only STELLAR-MASS BLACK HOLES OGLE3-ULENS-PAR-02 - candidate ~9MSun BH
OGLE photometry Gaia astrometry
OGLE photometry predicted from 2001-2008 Gaia astrometry and microlensing model for similar event
Mass, Distance Rybicki in prep. ASTROMETRIC PRECISION IN GAIA 50 mas : daily calibrations 1D precision!
Astrometricsignificant0.1 delayaccuracy: formas any given sourcesingle: fortnightly observation observation to be mapped ontocalibrations the global astrometric solution (assuming 6 monthly processing windows in the intial design). The IDT includes an astrometric solution (OGA1) with precision around 10-50 mas with a systematic error of around 50mas. OGA2 !"#$%&'()*&+,-."(#'-//0+-/1'(producedfinal by First Look)precision reduces the(+)".2'*(%-+'*1*.&3 error to around(in 1002022):µas and should be available within 24h after IDT (TBC). !"#$%'($)*+",&) -!&")$,!.*/# Gaia final WFIRST
!"#$%"$&'($)*+&,!-&./'-&01&23%$&0454 G-band mag 06 H-band mag
Figure 5: Astrometric performance across-scan for a point source from a single transit as a function of G magnitude. Gould+2017
4.2 Photometric Performance
The main photometry stream from Gaia is obtained from AF CCDs and is a broad filter photom- etry called G. Another source of the photometry is based on low-resolution, dispersive, spectro- photometry using the Blue and Red Photometers (BP and RP), from which we derive GBP ,GRP magnitudes. DU17 will receive both streams of the photometry in uncalibrated form. Figure 6 shows the expected error as a function of magnitude for each field-of-view transit.
4.3 Spectroscopic Performance
The underlying low-resolution epoch spectra from BP and RP will also be available from the IDT in a raw form. The BP/RP spectrograph comprises two low-resolution fused-silica prisms. The BP disperser covers 330-680 nm with resolution 4-32 nm/pixel, while the RP covers 640-1000 nm with resolution 7-15 nm/pixel.
8 ASTROMETRIC PRECISION IN GAIA 50 mas : daily calibrations 1D precision!
Astrometricsignificant0.1 delayaccuracy: formas any given sourcesingle: fortnightly observation observation to be mapped ontocalibrations the global astrometric solution (assuming 6 monthly processing windows in the intial design). The IDT includes an astrometric solution (OGA1) with precision around 10-50 mas with a systematic error of around 50mas. OGA2 !"#$%&'()*&+,-."(#'-//0+-/1'(producedfinal by First Look)precision reduces the(+)".2'*(%-+'*1*.&3 error to around(in 1002022):µas and should be available within 24h after IDT (TBC). !"#$%'($)*+",&) -!&")$,!.*/# Gaia final
WFIRST
!"#$%"$&'($)*+&,!-&./'-&01&23%$&0454 06
Figure 5: Astrometric performance across-scan for a point source from a single transit as a function of G magnitude. Gould+2017
4.2 Photometric Performance
The main photometry stream from Gaia is obtained from AF CCDs and is a broad filter photom- etry called G. Another source of the photometry is based on low-resolution, dispersive, spectro- photometry using the Blue and Red Photometers (BP and RP), from which we derive GBP ,GRP magnitudes. DU17 will receive both streams of the photometry in uncalibrated form. Figure 6 shows the expected error as a function of magnitude for each field-of-view transit.
4.3 Spectroscopic Performance
The underlying low-resolution epoch spectra from BP and RP will also be available from the IDT in a raw form. The BP/RP spectrograph comprises two low-resolution fused-silica prisms. The BP disperser covers 330-680 nm with resolution 4-32 nm/pixel, while the RP covers 640-1000 nm with resolution 7-15 nm/pixel.
8 STELLAR-MASS BLACK HOLES OGLE3-ULENS-PAR-02 - candidate ~9MSun BH
Combination of ground-based photometry and Gaia astrometry for long events will yield masses of black holes accurate to ~10% percent (brightness dependent) see Kris Rybicki’s POP Rybicki in prep. short break :) MICROLENSING EVENTS FROM GAIA July 2016 - July 2017 17bcu 16aye(bin) 17bbs 17ahk 16aua 17aqu 17bbi 17asv 17bts 17ahl 17bol 17bej 17ajg 17bdl 16bnn 17bdk ASASSN-16oe Gaia figure by Nadia Blagorodnova, OGLE fields by fields Jan Skowron OGLE by Blagorodnova, Nadia Gaia figure MICROLENSING EVENTS FROM GAIA
Gaia16aua (Auala) Gaia17aqu (Aqua)
Gaia16bnn Gaia17bbi (BB Is watching)
Gaia17bej (Bejeweled) Gaia17bbs (BB’s sister)
see Kasia Kruszynska’s poster/POP Gaia16AYErs Rock*
*Uluru GAIA16AYE (AYERS ROCK) GAIA16AYE (AYERS ROCK)
More than 20,000 data points collected in multiple bands by a network of volunteering observatories GAIA ALERTS FOLLOW-UP NETWORK ~20 active partners, ~30000 data points collected 2014-2016 2017-2020: continuation under OPTICON H2020 GAIA16AYE (AYERS ROCK) Catching the 4th caustic exit
Model prediction Caustic exit 21 November 2 am UT GAIA16AYE (AYERS ROCK) Catching the 4th caustic exit
Model prediction Caustic exit 21 November 2 am UT GAIA16AYE (AYERS ROCK) Catching the 4th caustic exit
Model prediction actual peak: 21 Nov ~16 UT Caustic exit 21 November 2 am UT GAIA16AYE (AYERS ROCK) Preliminary full-Keplerian orbital solution of the binary lens
tE = 141d piE= 0.39 thetaE=3 mas mu_rel=7mas/yr q=0.57 s=1.0 fs=0.75
model by P.Mroz and J.Skowron PRELIMINARY SOLUTION
~8kpc 0.8kpc
2.3AU
M1 = 0.4 MSun K3 giant M2 = 0.6 MSun R=~10 RSun P = 3.4 yrs incl = 60 deg ecc = 0.473 ASTROMETRY First time ever chance to detect binary astrometric microlensing!
Gaia obs moments
~3 mas SPACE PARALLAX FROM GAIA?
ground
Gaia
Offset in both time and mag between microlensing Earth-based and Gaia-based observations parallax SPACE PARALLAX FROM GAIA?
satellite recovered ground from safe mode
Gaia
Offset in both time and mag between microlensing Earth-based and Gaia-based observations parallax GAIA DATA RELEASES www.cosmos.esa.int/web/gaia DR1 14 September 2016: - positions for 1 billion stars - astrometric solution for 2 million stars (TGAS) (proper motion, parallax)
DR2 April 2018: - astrometric solution for 1 biliion stars - colors, temperatures, radial velocity DR3 2020: - improved astrometry - low-resolution spectra for all objects - radial velocity, variable stars - non-single stars DR4 (Final) 2022: - Full astrometric, photometric and radial velocity catalogs - All per-epoch astrometry and photometry - Exo-planets https://gea.esac.esa.int/archive/ SUMMARY
• Gaia will soon provide 3D map of the Milky Way • all data public in 2022 (after your PhD!) • Gaia sampling in the Bulge is too poor for microlensing • but Gaia finds microlensing in the MW Disk • astrometric microlensing from Gaia only for brighter events • space parallax possible Earth — Gaia (in L2) • WFIRST should have astrometric microlensing capability — great for measuring theta_E for black hole lenses!