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ESA UNCLASSIFIED – Releasable o he Public
7/10/2025
Johannes Sahlmann
Gaia P ojec Scien is
TITLE OF PRESENTATION
The ESA Gaia mission
and i s p omise o cool gian plane s
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Gaia e eals he o igin and e olu ion o he Milky Way
• S ella posi ions and dis ances
➡ Galac ic s uc u e
•S ella mo ions
➡ Galac ic kinema ics
• S ella pa ame e s, composi ions, ages
➡ Galac ic e olu ion
• Op ical all-sky su ey wi h 3 ins umen s:
As ome y, Pho ome y, Spec oscopy
• Gaia obse es ~1% o he s a s in he Galaxy
• Gaia su ey enables ich complemen a y science
C edi : ESA/Gaia/DPAC, S e an Payne-Wa denaa (sou ce)
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The Gaia spacec a is 10 m wide and has 2 elescopes
C edi : ESAC (sou ce)
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Gaia was launched o L2 in Decembe 2013
• 10.5 yea s o science obse a ions om July 2014 o Janua y 2025
• Gaia was cons an ly spinning and scanning he sky
• Su eying s a -like sou ces, e.g. s a s, galaxies, quasa s, as e oids, …
• Magni udes ange G ≈ 3-21
ESA/CNES/ARIANESPACE
C edi : ESA (sou ce)
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Gaia da a low om he spacec a o he ESA a chi e
Gaia conso ium incl. ESA
C edi : ESA (sou ce)C edi : ESA/ATG medialab (sou ce)
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DR3 2022
The e we e 3 in e media e Gaia da a eleases so a
•I e a i e p ocess o inc emen al da a eleases
•The e is no p op ie a y pe iod on science da a
o he Gaia collabo a ion
•h ps://www.cosmos.esa.in /web/gaia/da a
• Ea ly DR3 (2020)
• Focused P oduc Release
(5 p oduc s, 2023)
Da a imespan; Da a quali y; Da a olume; Numbe and de ail o ca alogues
DR1 2016
DR2 2018
C edi : ESA/Gaia/DPAC (sou ce)
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C edi : ESA/Gaia/DPAC, Milky Way imp ession by S e an Payne-Wa denaa (sou ce)C edi : ESA/Gaia/DPAC (sou ce)
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Gaia spacec a was passi a ed on 27 Ma ch 2025
C edi : ESA/Gaia/DPAC (sou ce)
• Gaia exhaus ed i s cold gas and
s opped science obse a ions on 15
Janua y 2025
• Gaia was pu in a heliocen ic o bi
and pe manen ly swi ched o
• ESA news elease:
h ps://www.esa.in /Enabling_Suppo
/Ope a ions/Fa ewell_Gaia!_Spacec
a _ope a ions_come_ o_an_end
•Addi ional in o ma ion:
h ps://www.cosmos.esa.in /web/gaia/
iow_20250327
h ps://www.cosmos.esa.in /web/gaia/
iow_20250929
• This is no he end o he mission
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Gaia is a e y p oduc i e science mission
C edi : ESA/Gaia/DPAC (sou ce)
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Gaia as ome y opens up a new exoplane window
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The Gaia collabo a ion is p epa ing Gaia Da a Release 4
•High quali y da a eleases: science- eady, calib a ed, and
alida ed da a p oduc s; ex ensi e documen a ion
DR1 2016 DR2 2018 DR3 2022
Gaia DR4
(planned Decembe 2026)
•5.5 yea s o da a ; ~500 TB
•New da a p oduc s
•Timese ies o all sou ces /
ins umen s
•P e iews, con en , and mo e
•New Science!
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Gaia DR4 as ome ic unce ain ies (median alue s. G)
DPAC/ CU3/
AGIS/ DPCE
eam
Pa allax P ope mo ion
expec ed imp o emen su passed o G<13 expec ed imp o emen eached o all G
Pa a y - 2024.11.19 - 10/27
P ope mo ion unce ain y
C edi : ESA/Gaia/DPAC (sou ce)
Upcoming Gaia DR4 is he “nominal mission” da a elease
• Gaia DR4 co e s 5.5 yea s (2014-2020) o Gaia da a
• Mo e da a, longe imespan, be e p ecision, highe accu acy
• >2 billion sou ces
• Mo e and new da a p oduc s, including lowe -le el da a:
•Time se ies o as ome ic da a + CCD images
•Ligh cu es: ime se ies o pho ome ic da a
•Radial eloci y ime se ies
•Time se ies o low- and high- esolu ion spec a
•New non-single-sou ce classes, sou ce en i onmen
in o ma ion, c owded ield images, and much mo e
• Gaia DR4 will lead o ano he lu y o disco e ies
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•Landing page: h ps://www.cosmos.esa.in /web/gaia/da a- elease-4
•Con en page: h ps://www.cosmos.esa.in /web/gaia/d 4
• Cu en ly incomple e lis o >100 da a ables and elease i ems. Upda es will be made g adually.
O e iew o Gaia DR4 and i s con en is public
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Gaia DR4 p e iew: as ome ic imese ies o Gaia BH3
h ps://www.cosmos.esa.in /web/gaia/iow_20240416
h ps://www.esa.in /Science_Explo a ion/Space_Science/Gaia/Sleeping_gian _su p ises_Gaia_scien is s
P elimina y as ome ic imese ies o
Gaia BH3 and an o bi - i ing no ebook
a e public:
h ps://gi hub.com/esa/gaia-bh h ee
Gaia splin e session
(Ség ansan & Delisle)
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Gaia DR4 as ome ic imese ies a e accu a e enough
o exoplane de ec ion
Gaia DR4 as ome ic imese ies “epoch_as ome y”
will con ain all indi idual CCD measu emen s (c .
gaiad 3.sso_obse a ion).
CCD-le el accu acy limi ed by calib a ion e o s o
≳80–150 µas a b igh end.
Epoch as ome y unce ain ies
✁Gaia DR4 o mal pe CCD as ome ic
unce ain ies →50 µas a G↭13
(→15 µas a e aged o e 9 CCDs)
✁Bu : o al unce ain ies limi ed by
calib a ion e o s o →80–150 µas
(30–50 µas a e aged o e 9 CCDs)
DPAC/ CU3/
AGIS/ DPCE
eam
Conclusions EAS2025 - 2025.06.26 - 5/23
C edi : ESA/Gaia/DPAC (sou ce)
As ome ic p ecision and accu acy
o indi idual CCD measu emen s
Combina ion o 9 CCD measu emen s limi ed o
≳ 30–50 µas pe Gaia Field-o -View ansi .
Pe yman+14 assumed 34 µas o G<13 s a s.
C edi : ESA (sou ce)
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Gaia as ome y opens up a new exoplane window
Gaia DR4 disco e y space
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Gaia DR4 will con ain an as ome ic exoplane
candida e ca alog
How many exoplane s will Gaia DR4 e eal?
•Numbe de ec ed by he DPAC pipelines?
•Numbe de ec able in Gaia DR4 epoch as ome y?
•Mass and pe iod ange?
•Comple eness o pu i y?
Twin bina y s a s can be as ophysical alse posi i es. Mi iga ed by e.g.
•Colou -magni ude modelling (Gaia Collab., A enou+23)
•Obse a ions (e.g. Ma cussen & Alb ech 23,
S e ánsson+25)
•Ensemble analysis (e.g. Sahlmann & Goméz 25)
Mos o he science will be done by he communi y
•Gaia DR4 as ome ic imese ies a e a gamechange
•As ome ic accele a ions o long-pe iod sys ems
•Combina ion wi h o he echniques is e y powe ul
Con ibu ions by Bouchy, G een ield,
Handley, Nowak, Pa c, Van Zand ,
Schlau man, and o he s.
Gaia splin e session
No o scale
Con i med
Exoplane s
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Gaia Da a Release 5 will cons i u e he mission’s legacy
• Gaia DR5 (10.5 yea s o da a) planned no be o e end o 2030
DR1 2016 DR2 2018 DR3 2022
Gaia DR4
(planned Decembe 2026)
•5.5 yea s o da a ; ~500 TB
•New da a p oduc s
•Timese ies o all sou ces /
ins umen s
•P e iews, con en , and mo e
•New Science!
Gaia DR5
(No be o e end 2030)
•10.5 yea s o
Gaia da a
•~1 PB in ESA
a chi e
•Gaia’s legacy
•New Science!
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Gaia and ESA esou ces a you inge ips
• Gaia gene al in o ma ion and news eleases: h ps://www.esa.in /Science_Explo a ion/Space_Science/Gaia
• In o ma ion o Gaia scien i ic communi y: h ps://www.cosmos.esa.in /web/gaia
• Recei e Gaia da a use no i ica ions by signing up o he Gaia Bulle in emailing lis :
h ps://www.cosmos.esa.in /web/gaia/bulle in
• In e es ed in boos ing he isibili y o you Gaia- ela ed esea ch wi h an ESA news elease? See
h ps://www.cosmos.esa.in /web/gaia/communica ing-you - esul s
• Please acknowledge he use o Gaia da a in you esea ch: h ps://www.cosmos.esa.in /web/gaia-use s/c edi s
•In o ma ion on ESA A chi al Resea ch Visi o P og amme: h ps://www.cosmos.esa.in /web/esdc/ isi o -
p og amme (nex deadline 10 No embe 2025)
•In o ma ion on ESA Resea ch Fellowships in Space Science: h ps://www.cosmos.esa.in /web/space-
science- acul y/oppo uni ies/ esea ch- ellowships (nex call expec ed in he hi d qua e o 2026)
