K(2 K(2 m) Version of m) Version of JASMINEJASMINE

and its Scienceand its Science

Advantage in Bulge Science Advantage in Bulge Science andand

Potential By-products from Idle TimePotential By-products from Idle Time

T. Nakajima (NAOJ)T. Nakajima (NAOJ)

Demand from InstrumentationDemand from Instrumentation

Radiation cooling at L2 point sets telescope envRadiation cooling at L2 point sets telescope environmental temperature down to about 50K.ironmental temperature down to about 50K.

Since the operating temperature of CCDs is aboSince the operating temperature of CCDs is about 150K, they must to warmed up!ut 150K, they must to warmed up! 　　　　　　　　　　　　　　　　 　　　　　　 ----- Detectors are heat source----- Detectors are heat sources.s.

The operating temperature of HgCdTe NIR arraThe operating temperature of HgCdTe NIR arrays is about 70K. ys is about 70K. 　　　　 　　　　　 　Better matching with environmental temperaturBetter matching with environmental temperature.e.

Abstract of K (2 Abstract of K (2 m) Sciencem) Science Main advantage of JASMINE-KMain advantage of JASMINE-K

A. astrometric accuracy of Bulge stars with Av>6 is better A. astrometric accuracy of Bulge stars with Av>6 is better compared with that at z band (0.9 compared with that at z band (0.9 m).m).

B. Since, AB. Since, AZZ ~ 4 A ~ 4 AK , K , QSO/AGN count is much greater at QSO/AGN count is much greater at K. They behave as fixed positional references.K. They behave as fixed positional references.

By-productsBy-products More than 1 / 4 of the mission period should be used for otMore than 1 / 4 of the mission period should be used for ot

her purposes such as NIR deep survey due to the Bulge-Suher purposes such as NIR deep survey due to the Bulge-Sun coincidence.n coincidence.

At high Galactic latitudes, the limit of galaxy count is set bAt high Galactic latitudes, the limit of galaxy count is set by confusion to K = 24 ~ 25.y confusion to K = 24 ~ 25.

An example of science program: A search for QSOs beyonAn example of science program: A search for QSOs beyond z = 7.d z = 7.

Main advantages for bulge starsMain advantages for bulge stars Bulge GiantsBulge Giants

Intrinsic SEDs are red.Intrinsic SEDs are red. Combining the SED and extinction, astrometric errCombining the SED and extinction, astrometric err

or given by or given by σσ~ ~ /D/√N, is smaller at K than z for /D/√N, is smaller at K than z for Av > 6. Av > 6.

Background QSO countBackground QSO count If we estimate the QSO number count in JASMINIf we estimate the QSO number count in JASMIN

E field of 200 sq. deg from extinction-free high latE field of 200 sq. deg from extinction-free high latitude QSO counts, a meaningful number of them aritude QSO counts, a meaningful number of them are expected. e expected.

Identification of these QSOs prior to the mission, aIdentification of these QSOs prior to the mission, and long-exposures of these QSO fields at the missind long-exposures of these QSO fields at the mission will necessary.on will necessary.

Relative astrometric accuracy of BulRelative astrometric accuracy of Bulge giants between z and Kge giants between z and K

K is better

if

σz/σK>1.

Range of QSO countRange of QSO countin 200 sq deg JASMINE fieldin 200 sq deg JASMINE field

Assumptions: Av=0. fAssumptions: Av=0. fνν~ ~ νν-1-1 for QSOs. for QSOs. UV – excess selected quasars (large U-B, or u-g) UV – excess selected quasars (large U-B, or u-g)

PG quasars w/ correction n(K<11.8) < 3.4.PG quasars w/ correction n(K<11.8) < 3.4. LBQS n(K<14) ~ 200, n(K<13)~125, n(K<12) ~ 3. LBQS n(K<14) ~ 200, n(K<13)~125, n(K<12) ~ 3.

Fainter and more distant QSOs from SDSSFainter and more distant QSOs from SDSS Including narrow-line QSOs/AGNsIncluding narrow-line QSOs/AGNs n(K<13.8) > 4.0. (SDSS misses brightest ones.)n(K<13.8) > 4.0. (SDSS misses brightest ones.)

Variability selection Variability selection n(K<15.4) ~ 1000 (SDSS, n(K<15.4) ~ 1000 (SDSS, σσvar var > > 0.03 mag)0.03 mag) n(K<16.3) > 400 (MACHO,LMC,+color)n(K<16.3) > 400 (MACHO,LMC,+color)

Extragalactic astronomy during the Extragalactic astronomy during the idle time of Bulge observationsidle time of Bulge observations

How to utilize 1 / 4 of astrometry idle time?How to utilize 1 / 4 of astrometry idle time? Taking advantage of a wide FOV Taking advantage of a wide FOV

(0.7x0.7deg).(0.7x0.7deg). Advantage of NIR imaging from space.Advantage of NIR imaging from space.

The zodiacal background has its minimum in NIR, The zodiacal background has its minimum in NIR, since its a valley between scattered Sun light in the since its a valley between scattered Sun light in the visible and thermal dust emission in MIR.visible and thermal dust emission in MIR.

Telescope thermal emission is negligible at L2.Telescope thermal emission is negligible at L2. Re-ionization era (z=10~17) can be probed at rest-Re-ionization era (z=10~17) can be probed at rest-

frame UV at K band. frame UV at K band.

Sensitivity at K (Point source)Sensitivity at K (Point source)

Lrest

(Lsun)

Age of Univ.

rest

(m)

K band (5 kpc extended sourcK band (5 kpc extended sourcee ））

H (1.6) band (Point sourceH (1.6) band (Point source ））

H(1.6) band (5kpc extended H(1.6) band (5kpc extended sourcesource ））

Sky at K (Vega) > 23 Sky at K (Vega) > 23

Cumulative galaxy count (Eg. Minowa et al. 2Cumulative galaxy count (Eg. Minowa et al. 2006)006) 1 galaxy in 10 square arcsec. (1 in 3”x3”) at K~23.1 galaxy in 10 square arcsec. (1 in 3”x3”) at K~23. Since galaxies are extended, better resolution (largSince galaxies are extended, better resolution (larg

er telescope) does not necessarily remedy the confer telescope) does not necessarily remedy the confusion problem. --- there may be more than one galausion problem. --- there may be more than one galaxy for each line of sight at K>25.xy for each line of sight at K>25.

In one quarter of the mission life of JASMINIn one quarter of the mission life of JASMINE, 5,000 ~ 10,000 sq. deg. will be surveyed.E, 5,000 ~ 10,000 sq. deg. will be surveyed.

Conceivable New Science ProgramsConceivable New Science Programs

QSO/AGN survey up to z ~ 13 (H dropout).QSO/AGN survey up to z ~ 13 (H dropout). My empirical number count estimation in 10,000 sq. deg.My empirical number count estimation in 10,000 sq. deg. 3 for M3 for M145145 < -26 (10 < -26 (101212 Lsun) between z=10 & 13. Lsun) between z=10 & 13.

6 for M6 for M145145 < -25 (3x10 < -25 (3x101111 Lsun) between z=10 & 13. Lsun) between z=10 & 13. Foreground ISM study or locating high density regions.Foreground ISM study or locating high density regions.

Wide-filed galaxy count down to K=24Wide-filed galaxy count down to K=24

and/orand/or Extragalactic NIR background radiation, Extragalactic NIR background radiation,

if superposition of faint galaxies is inevitable.if superposition of faint galaxies is inevitable.