Sagan Workshop, Pasadena, 10 August 2017

Łukasz Wyrzykowski(pron: Woo-cash Vi-zhi-kov-ski)

Warsaw University Astronomical Observatory, Poland

ASTROMETRIC MICROLENSING WITH GAIA

Krzysztof Rybicki(PhD student)

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)

COLLABORATORShere

here

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)

anim

atio

ns b

y S.

Gau

di

photometry (sum of images) astrometry (centroid motion)

~1 month ~1mashttp://www.astronomy.ohio-state.edu/~gaudi/movies.html

•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?

BLACK HOLES MICROLENSING

M =✓E⇡E

high amplification events/finite source (rare)

astrometry (VLT/AO, HST, Gaia)

Earth parallax

space-based parallax (e.g., Earth-Spitzer)

19 DEC 2013 9:12 UT

GAIA SPACE MISSION

GAIA FOCAL PLANE

windows observed:

Gaia focal plane (106 CCDs)

detection and FOV

discrimination

astrometric measurements

photometry (dispersed

images)

radial velocity (dispersed images)

BAM = basic angle monitor, WFS = wavefront sensor W

FS1

WFS

2 B

AM

2 B

AM

1

SM

1

SM

2

AF1

AF2

AF3

AF4

AF5

AF6

AF7

AF8

AF9

BP RP

RV

S1

RV

S2

RV

S3

0.42

m

0.93 m

AC

AL

Gaia focal plane (106 CCDs)

detection and FOV

discrimination

astrometric measurements

photometry (dispersed

images)

radial velocity (dispersed images)

BAM = basic angle monitor, WFS = wavefront sensor

WFS

1

WFS

2 B

AM

2 B

AM

1

SM

1

SM

2

AF1

AF2

AF3

AF4

AF5

AF6

AF7

AF8

AF9

BP RP

RV

S1

RV

S2

RV

S3

0.42

m

0.93 m

AC

AL

star<20magdetected!

Placewindow.

Gaia focal plane (106 CCDs)

detection and FOV

discrimination

astrometric measurements

photometry (dispersed

images)

radial velocity (dispersed images)

BAM = basic angle monitor, WFS = wavefront sensor W

FS1

WFS

2 B

AM

2 B

AM

1

SM

1

SM

2

AF1

AF2

AF3

AF4

AF5

AF6

AF7

AF8

AF9

BP RP

RV

S1

RV

S2

RV

S3

0.42

m

0.93 m

AC

AL Animation by Berry Holl, Geneva

~45 sec~4.4 sec

Camera: 0.75 deg2

pixel size:10x30 µm

(59x177 mas)

GAIA FOCAL PLANE

figure curtesy: Berry Holl, Geneva

GAIA SKY SCANNING PATTERN

Gaia Science Alerts

Polish 1.3m dedicated telescope in Las Campanas, Chile Surveying continuously since 1992.

ESA space mission with 2x1.4m telescopes located in L2.In operation since 2014.

http://ogle.astrouw.edu.pl

http://gsaweb.ast.cam.ac.uk/alerts

HOW TO FIND BLACK HOLES?

Number of Gaia observations after 5 years Gai

a fig

ure

by N

adia

Bla

goro

dnov

a, O

GLE

fiel

ds b

y Ja

n Sk

owro

n

OGLE-GAIA SKY

OGLE3-ULENS-PAR-02 - candidate ~9MSun BH

OGLE photometryfrom 2001-2008 and microlensing model

Mass, Distance estimate only

STELLAR-MASS BLACK HOLES

OGLE photometry

probability distribution for the proper motion

based on observed PM

Rybicki in prep.

OGLE3-ULENS-PAR-02 - candidate ~9MSun BH

predicted Gaia astrometry for similar event

OGLE photometryfrom 2001-2008 and microlensing model

Mass, Distance

STELLAR-MASS BLACK HOLES

Gaia astrometryOGLE photometry

ASTROMETRIC PRECISION IN GAIA

significant delay for any given source observation to be mapped onto the global astrometric solution(assuming 6 monthly processing windows in the intial design). The IDT includes an astrometricsolution (OGA1) with precision around 10-50 mas with a systematic error of around 50mas. OGA2(produced by First Look) reduces the error to around 100µas and should be available within 24hafter IDT (TBC).

!"#$%"$&'($)*+&,!-&./'-&01&23%$&0454 06

Astrometric accuracy: single observation

� !"#$%&'()*&+,-."(#'-//0+-/1'� (+)".2'*(%-+'*1*.&3

� !"#$%&#'($)*+",&)

� -!&")$,!.*/#

Figure 5: Astrometric performance across-scan for a point source from a single transit as a functionof G magnitude.

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 6shows 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 IDTin a raw form.

The BP/RP spectrograph comprises two low-resolution fused-silica prisms. The BP disperser covers330-680 nm with resolution 4-32 nm/pixel, while the RP covers 640-1000 nm with resolution 7-15nm/pixel.

8

50 mas : daily calibrations 0.1 mas : fortnightly calibrations final precision (in 2022):

H-band magGould+2017

WFIRSTGaia final

G-band mag

1D precision!

ASTROMETRIC PRECISION IN GAIA

significant delay for any given source observation to be mapped onto the global astrometric solution(assuming 6 monthly processing windows in the intial design). The IDT includes an astrometricsolution (OGA1) with precision around 10-50 mas with a systematic error of around 50mas. OGA2(produced by First Look) reduces the error to around 100µas and should be available within 24hafter IDT (TBC).

!"#$%"$&'($)*+&,!-&./'-&01&23%$&0454 06

Astrometric accuracy: single observation

� !"#$%&'()*&+,-."(#'-//0+-/1'� (+)".2'*(%-+'*1*.&3

� !"#$%&#'($)*+",&)

� -!&")$,!.*/#

Figure 5: Astrometric performance across-scan for a point source from a single transit as a functionof G magnitude.

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 6shows 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 IDTin a raw form.

The BP/RP spectrograph comprises two low-resolution fused-silica prisms. The BP disperser covers330-680 nm with resolution 4-32 nm/pixel, while the RP covers 640-1000 nm with resolution 7-15nm/pixel.

8

50 mas : daily calibrations 0.1 mas : fortnightly calibrations final precision (in 2022):

Gould+2017

WFIRST

Gaia final

1D precision!

Rybicki in prep.

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)

STELLAR-MASS BLACK HOLES

see Kris Rybicki’s POP

short break :)

MICROLENSING EVENTS FROM GAIA

Gai

a fig

ure

by N

adia

Bla

goro

dnov

a, O

GLE

fiel

ds b

y Ja

n Sk

owro

n

July 2016 - July 2017

16au

aA

SASS

N-1

6oe

16bn

n

16ay

e (b

in)

17ah

k17

ajg

17aq

u

17as

v

17ah

l

17bb

i

17bb

s17

bcu

17bd

k17

bdl

17be

j

17bo

l17bt

s

MICROLENSING EVENTS FROM GAIAGaia16aua (Auala)

Gaia16bnn

Gaia17bej (Bejeweled)

Gaia17aqu (Aqua)

Gaia17bbi (BB Is watching)

Gaia17bbs (BB’s sister)

see Kasia Kruszynska’s poster/POP

*Uluru

Gaia16AYErs Rock*

GAIA16AYE (AYERS ROCK)

GAIA16AYE (AYERS ROCK)More than 20,000 data points collected in multiple bands

by a network of volunteering observatories

~20 active partners, ~30000 data points collected 2014-20162017-2020: continuation under OPTICON H2020

GAIA ALERTS FOLLOW-UP NETWORK

Catching the 4th caustic exit

Model prediction Caustic exit 21 November 2 am UT

GAIA16AYE (AYERS ROCK)

Model prediction Caustic exit 21 November 2 am UT

Catching the 4th caustic exit

GAIA16AYE (AYERS ROCK)

Catching the 4th caustic exit

actual peak: 21 Nov ~16 UTModel prediction Caustic exit 21 November 2 am UT

GAIA16AYE (AYERS ROCK)

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 full-Keplerian orbital solution of the binary lens

GAIA16AYE (AYERS ROCK)

~8kpc

0.8kpc

M1 = 0.4 MSun M2 = 0.6 MSun

P = 3.4 yrs incl = 60 deg ecc = 0.473

K3 giant R=~10 RSun

2.3AU

PRELIMINARY SOLUTION

First time ever chance to detect binary astrometric microlensing!

Gaia obs moments

~3 mas

ASTROMETRY

Offset in both time and mag between Earth-based and Gaia-based observations

microlensing parallax

Gaia

ground

SPACE PARALLAX FROM GAIA?

Offset in both time and mag between Earth-based and Gaia-based observations

microlensing parallax

Gaia

groundsatellite recovered from safe mode

SPACE PARALLAX FROM GAIA?

GAIA DATA RELEASESwww.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!