1. Infrared Space Astrometry mission for the Galactic Bulge
Naoteru Gouda
JASMINE Project Office
National Astronomical Observatory of Japan
3 Dec. 2013 1

2. §1. Galactic Bulges
§2. Surveys of the bulge of the Milky Way galaxy
(the Galactic bulge)
§3. Astrometry and Upcoming space astrometry
missions
§4. Small-JASMINE project
§5. WISH as an infrared space astrometry mission

3. §1. Galactic Bulges ：key tracers of galaxy formations
Bulges are complex!
Classical bulges: e.g. M81 [NASA]
Disk-like bulges (aka pseudo-bulges): e.g. NGC 6782 [NASA]
Box/Peanut bulges (aka pseudo-bulges):
e.g. ESO 597-G 036 [NASA]
Classical bulges
Disk-like bulges(aka pseudo-bulges)
Box/Peanut bulges(aka pseudo-bulges)
〇 stick out of disk plane
(not as flat as the disk)
〇more or less sphroidal
〇featureless: no spiral arms,
bars, rings,…
〇mostly old stars
〇kinematically hot:
dynamically supported by
stellar velocity dispersions
〇seem to be built mostly
by mergers,
fast bursts of star formation
〇 as flat as the disk
〇substructures: nuclear bars, spiral arms,
rings,…
〇young stellar populations or
ongoing star formation
〇kinematically cold:
dynamically supported by
rotation of its stars
〇seem to be built mostly via disk
instabilities: continuous, smooth process
〇stick out of the disk
〇box or peanut-like morphology
〇usually featureless
〇usually does not show young stellar
populations or star-forming regions
〇kinematically cold:
dynamically supported by
rotation of its stars
〇the inner parts of bars that grow
vertically thick due to dynamical
instabilities!
・Formations and evolutionary processes of galaxies
Key issue:
Features of each type,
origin and evolution
・Orbits of stars, phase space density
　 in complex structures of bulges

4. Co-evolutions of super massive BH s and bulges
★Supper massive BH at the galactic center Activity of the galaxy
Origin and evolution of the super massive black hole at the
Galactic center?
merging of small　and/or medium BHs?
gas accretion?
★The mass of SMBH correlates with the mass of the bulge.
(Marconi & Hunt 2003, ApJ, 589, L21)
Magorrian relation
(STScI/NASA)
Connected growth of BHs and bulges!?

5. §2. Surveys of the bulge of the MW
high-quality observational data( both kinematical and chemical) to test
the theories regarding the origin and subsequent history of the bulges
=>The Milky Way: very important target galaxy!!
It is possible to observe in the Milky Way indivisual stars in many directions and to obtain information on their 3-dimensional positions,
3-dimensional velocities and metalicity with good accuracies, which is, in, general, still not possible for galaxies outside the MW.
The Milky Way
box/peanut bulge!
COBE/Diffuse Infrared Background Experiment, etc.
Vertically thin long bar + vertically thick inner part(box/peanut)
*Bars themselves can evolve secularly through angular momentum
transport, producing different boxy/peanut and X-shaped bulges
The properties of the bar affects dynamics :
spiral arm location, resonances, gas inflow, etc.
Clarification of the Galactic bar/bulge and its origin
 Very important for studies of the formation and evolution of disk- galaxies

6. ★Surveys of the bulge of the MW are necessary and important!
VVV survey: ZYJHKs Photometry＋100 epochs in Ks
Bulge 300 sq deg.
VISTA 4.1m telescope at ESO
sensitivity:0.84 to 2.5 microns
APOGEE survey:
High-resolution H-band spectroscopic survey
2.5m telescope at the Apache Point Observatory
APOGEE-1(SDSS-III):
100,000 giants to magnitude H=12.5
Bulge stars:7000
R~ , S/N~100
Wavelength mm
velocity error 0.5 km/s
15 elements error of 0.1 dex
APOGEE-2(S) (SDSS-IV) has been proposed to NSF
The same instrument as that of APOGEE-1
will be set at Las Canpanas Observatory
~90,000stars in the bulge
Mission period:

7. ★VVV, APOGEE, BRAVA, ARGOS,・・・
Photometry, radial velocities and elemental abundances of stars in the bulge of the MW
Furthermore we need astrometric parameter:
・annual parallax
・proper motion
3-dimensional positions and velocities of stars
will be provided.

8. Helical motion of a star
§3. Astrometry and Upcoming space astrometry
missions
Astrometry: Fundamental task of measuring stellar positions
Repeated measurements
2D-positions of stars in space
Trace of a star : Helical motion annual parallatic ellipse　＋　proper motion(straight line)
Helical motion of a star 8

9. Helical motions of stars
1. Apparent annual elliptical motion
*Parallactic Ellipse (annual parallax)
　　　　　　Distances of stars
2. Systematic displacement of stellar
positions
Proper motion
*Proper motion + Distance
　　　　 　　Tangential velocities of stars
Helical motions of stars
Astrometry＝＞
important information of distances and tangential velocities of stars 9

10. Residual motions from the helical motion
Very important information !!
Binary systems, Planetary systems,
Gravitational lens effects, effects of starspot, etc.
Periodic residual motions
Physical characters such as
mass of binary stars,
mass of planets etc.

11. Space Astrometry Projects
Remark:
Infrared astrometry mission
(Small-JASMINE) has
advantage in observing stars
in the Galactic bulge,
hidden by interstellar dust
in optical bands.　　　　　　　 11 11

12. *Gaia will be launched at 19th Dec. ,2013.
★Gaia(ESA’s mission)
　*Gaia will be launched at 19th Dec. ,2013.
　 *The final catalogue will be released in 2021.
*all sky survey in an optical band
　*G-band（ micron）、　6mag＜G<20mag
　　　　 *accuracies of parallax: 7~300mas(6<G<20mag)
G = V · (V-IC) · (V-IC) · (V-IC)3
(fit error of 0.05mag) 12
The predicted errors vary over the sky

13. Near the Galactic center
§4. Small-JASMINE project
Astrometric Measurement in Hw-band
(1.1mm~1.7mm)
Infrared astrometry missions have advantage in surveying the
Galactic bulge, hidden by interstellar dust in optical bands!
Accuracy:
parallax:
10 m as ~70 m as for Hw<11.5mag
*10 m as distance
　　proper motion:
10m as/yr ~70 m as/yr for Hw<11.5mag
*tangential velocity accuracy:
(if the distance is accurately determined)
position:
8 m as ~40 m as for Hw<11.5mag
photometry(Hw-band)
<0.01 mag
Survey Area:
Near the Galactic center
+ some directions toward interesting target objects
(e.g CygX-1, planeray systems, browndwarfs. star-forming regions besides the area near the center) 13

14. toward the Galactic bulge：
The Number of Objects:
toward the Galactic bulge：
<10kpc: ~120,000　　(6kpc<d<10kpc: 88,000)
（highest accuracy region 　　　　　: <10kpc :10,000, 6kpc<d<10kpc: 6,700)
Multi color photometry: J, H and Hw(astrometry)
The target launch date is around ~2019
Hw<11.5mag
＊Proposal of SJ mission to small science-satellite missions executed
by JAXA in Feb.2014.
Mission life: ~3 years
Orbits: sun synchronized orbit ~550km
Launcher: Epsilon launch vehicle(solid rocket) provided
by JAXA
Small JASMINE
Development effort of NAOJ with JAXA (Japan Aerospace eXploration Agency)
and universities in Japan 14

15. Advantage of Small-JASMINE
Small-JASMINE is a unique space astrometric measurement in Hw-band to get the accurate astrometric data for many stars in our Galactic bulge.
Survey area of
Small-JASMINE
Small-JASMINE: ~ a few 103 stars of the bulge in its small survey area (with <0.1)
Gaia: ~a few stars of the bulge in the same area as that in Small-JASMINE (with <0.1)
★Another advantage: High time resolution!!
Small-JASMINE will measure the same target every 100 minutes if the target is located towards the Galactic bulge .
If a target is located toward other direction and Small-JASMINE can measure it
in summer or winter season, Small-JASMINE measure it frequently as needed.
*Gaia can measure the same target every one or two months. 15

16. Scientific targets of Small-JASMINE
1. The origin and evolution of the Galactic bulge
　　＊3D-distributions of stellar positions and velocities in the inner part
of the bulge 　　　　
its origin and relation to
galaxy formations and evolutions
　　＊star formation history in the Galactic bulge
2. Astrophysics around the Galactic center
　　＊Formation of Super massive black hole at the Galactic center
Effect on stellar velocity distribution
　　＊Motion of star clusters the origins of star clusters,
the gravitational potential field around the Galactic center
　　＊existence of an inner bar structure effect on star formation around the center
＊Frequent and long-period monitor of SgｒA* existence of QPO
Informtion of spin of SM-BH

17. Scientific targets of Small-JASMINE
3. Compact celestial objects
＊Determination of orbit element of X-ray binaries and g-ray binaries
 Big revolution! physics of accretion disk and jets, etc.
　　　*a good candidate of X-ray bursts：Cyg X-1:(l=71°, b=+3°)
period:5.6 days( unmeasurable by Gaia)
companion star: mv~9mag , change of the position: 40~50μas measurable
by Small-JASMINE *
*the Galactic ridge X-ray dim point sources
CVs(cataclysmic variables, symbiotic star) or late-type stars
4. Extra-planets
＊detection of planets by astrometric method
(e.:g. primary star low-mass star(late M-dwarf, brawn dwarf): H-10mag,V=16-18mag)
5. Gravitational lens: Search of Wormholes!?
6. Stellar physics, Star formation
＊3-Ddistribution of inter -stellar dust
＊annual parallax and proper motions of Mira-type variable stars in the bulge
Good candidates of g-ray bursts: LS5039,　J1018,　LSI+61

18. Small-JASMINE for these scientific targets
Information of radial velocities , chemical composition and photometry (in other bands) is complementary to
Small-JASMINE for these scientific targets
in the Galaxy.
Cooperation with APOGEE-S and VVV is
very strong synergy
for studies of the Galactic bulge.
MOU for　powerful scientific collaboration
between APOGEE-2(S), SDSS-IV collaboration and Small-JASMINE has been concluded.

19. Design of Small-JASMINE instrument
Optics design: Modified Korsch System (3mirrors)
Material: Synthetic Silica
Aperture size: m
Focal length: m
Field of view: 0.6 degree degree
Detector:
Hw-band: HgCdTe(H4RG), Number of detectors: 1
pixel size:10mm
the number of pixels:
potential well:100,000
read-out noise :30e
J, H-bands
for photometry
Structure model of
the mission system (JAXA) 19

20. Integration System Design task of the integration system
Satellite system
-Compatibility of the bus system
-Control system of the pointing of
the telescope
-Thermal structure
commission the task to companies
 prospects are almost good
Small-JASMINE　Ｓａｔｅｌｌｉｔｅ　ｓｙｓｙｔｅｍ
Ｍｉｓｓｉｏｎ　system
Ｂｕｓ　system
Ｔｈｅｒｍａｌ　ｃｏｎｔｒｏｌ
Ｓｔｒｕｃｔｕｒｅ
Ｔｅlｅｍｅｔｒｙ
Ｄａｔａ　ｈａｎｄｌｉｎｇ
Electronic power
Attitude control
2nd propulsion
第53回　宇宙科学技術連合講演会 20 20

21. We need astrometric measurements for
★Small-JASMINE will provide many interesting results in wide fields of astronomy and astrophysics.
We need astrometric measurements for
the Galactic bulge survey with larger area
which overs the whole region of the bulge
than the survey area of the Small-JASMINE.
however

22. §5 . WISH as an infrared space astrometry mission
WISH：wide survey with accurate measurements in infrared bands
WISH has high possibility to play a role as an infrared astrometry
mission for the Galactic bulge
astrometric measurements with achievement of ~10mas accuracy
WISH
Pointing stability（70mas/3sec) of the telescope and thermal stability(~0.1K/30h) of the instruments are required in the design of the WISH satellite.
Required stability of the pointing of the telescope for WISH　(70mas/300sec) is
sufficient enough to achieve 10μas precisions of asttrometric measurements.
*The Galactic bulge survey with area of 6°(b)×16°(l)
*Precisions of ~10μas（K<11mag)
*necessary observation time:
0.6years/5years(1.4months/1year:
20days in spring and 20days in autumn)
*option: survey area of 3°(b)×16°(l)
0.3years/5years

23. Our JASMINE team is willing to contribute to the WISH
mission for the resolution of technical issues, the development
of the satellite, and data analysis
if WISH will play a role as an infrared astrometry mission
for the Galactic bulge!!
We hope that the WISH mission will be successful.

24. Thank you for your attention.
Jasmine
Thank you for your attention.