南極活動の新しい方向性
将来のスペースとのリンク
松尾 宏
国立天文台・先端技術センター

Angular Scale of Observation
All Sky

3°10″THzGap
10 mas10 mas

910111213
Log Frequency [Hz]14

Studies in US and EU⚫ In US– Far-IR Community Workshops in 2014 and 2015

– Single Dish or Interferometry ?
– Origins Space Telescope⚫ In EU– ESPRIT, FIRI
– FP7-FISICA (Far-IR Space Interferometer Critical Assessment)– HEterodyne Receiver for Origins (HERO)The Space Infrared Interferometric
Telescope (SPIRIT)
A Far-IR Observatory for High-resolution
Imaging and Spectroscopy

Dave Leisawitz
NASA Goddard Space Flight CenterBETTII (Balloon Experimental Twin Telescope forInfrared Interferometry)

Furst et al., JATIS 2, 024001 (2016)

ESA Voyage 2050 White Papers⚫ Atmospheric characterization of terrestrial exoplanets in theMid-infrared: biosignatures, habitability & diversity– Nulling interferometer, four 2.5 m telescopes, 170 m baseline– CH4, O3, N2O, CO2, H2O⚫ Bringing high spatial resolution to the Far-infrared – A

giant leap for astrophysics– Heterodyne interferometer, five 4 m telescopes, 1 km baseline– or Deployable single dish telescope 20 m diameter– H2O, atomic lines, HD112mm

ESA Voyage 2050 White Papers⚫ TeraHertz Exploration and Zooming in for Astrophysics(THEZA)– Event Horizon Imager with two 4.4 m telescope VLBI– Less than 10 marcsec resolution⚫ The Far-Infrared Spectroscopic Surveyor (FIRSS)– Heterodyne Receivers on 1-2 m Single Dish; atomic lines⚫ Origins Space Telescope: From First Light to Life (OST)– Far-Infrared Cryogenic Telescope; H2O, atomic lines, HD112mm– Background limited observation (+ Heterodyne receivers ?)H2Oの観測
Infrared Space Observatory
Water ice feature at 43/63 mm

HD142527Malfait et al. (1999)
Pontoppidan et al. (2019)

MuFT
Multi-Fourier Transform
interferometer⚫High Dynamic Range⚫Imaging Spectrometer⚫Polarizing beam combiner

Ohta et al. Appl. Opt. 45, 2576 (2006)
Ohta et al. Appl. Opt. 46, 2881 (2007)

MuFT andHeliostat
in Nobeyama
2005

MuFT image of the sun
A. baselines sampled
B. synthesized beam
C. simulated image

D. observed image

Ohta et al.
IRMMW-THz2007

The Most Transparent Atmosphere from Dome A
Ice Feature at 7 THz[NII]
1.5 THz[OIII]
5.8 THz[OIII]
3.4 THz

August 9th 12-18h UTC, 2010
Matsuo et al., Advances in Polar Science 30, 76 (2019)

Windows for [NII], [OIII] andIce Feature

August 9th 12-18h UTC, 2010
Matsuo et al., Advances in Polar Science 30, 76 (2019)

Can we observe [OIII] 88 mm
at 3.393 THz ?

in July - August, 2010
Matsuo et al., Advances in Polar Science 30, 76 (2019)

高感度と高解像度の両立は？
⚫ ヘテロダイン受信機の量子雑音– Tｒｘ = hn/k [K] = 500 K @10 THz⚫ 結合型干渉計の基線長制限

強度干渉計の提案

Narrabri Stellar Intensity Interferometer

AT N F D a i l y As t r o n o m y
17th of August 2015Picture

Fluctuation of thermal radiation12n = n + n , where n =e

hn kT

−1n : photon occupation numberA = 2NEP = 2 P  (hn + kTB ) [ WReferences

A. Einstein (1909)
J. Mather (1984)
J.M. Lamarre (1986)
J. Zmuidzinas (2003)

Hz ]T=TB / √Bt

Photon bunchingTHz photon fluctuation
10 cm

kT 1 nW

hn 1 nW

250 K

hn 10 pW

2.5 K

B = 100 GHz

10 mm

1 mm

kT 10 pW

Antarctic THz Intensity
Interferometry

Two 30-cm THz telescopes

RecorderB > 1GHzRecorderB > 1GHz

Calculate correlation and delay

Photon Bunches fordelay time measurements⚫ Photon bunch can be a measure of delay time.
– Complex visibility can be obtained.

⚫ Large number of THz photon is expected.

100 M photons/sec from Stars and AGNs
1 Jy at 1 THz (B=100 GHz), using f10 m telescopet = 10-13 sec in 100 sec is expected.
𝛥𝑡 =THz Photons are bunched !

1𝑁 𝑁∙𝜏

N: photon ratet : integration time

Nobeyema Radioheliograph at 17 GHz
Antenna Temperature T A* [K]Amplitude
Correlation

Intensity
CorrelationSystem Temperature Tsys [K]delay

Correlation amplitude

Frequency n [Hz]Bandwidth n [Hz]Tsys11t = * [s]T A n t n
 = 2nt [rad]t ~ 5ps in 50 ms integration
Ezawa, Matsuo et al. (2015)

Background limited observation withSpace Far-IR Intensity Interferometry⚫ Quantum noise of heterodyne receivers– TQL = hn/k [K] = 150 K @ 3THz

10-14

– n = kTQLB/hn = B [photons/s]⚫ Background limit of direct detectors

Quantum Limit– NEP = 10-19 W/Hz0.5, B =100 GHz– TRX = NEP / (2k B0.5) = 10 mK

10-16
Atmospheric Limit

10-17– Background vs. Quantum limit~ 4 orders

10-18
Cosmic Background Limit
10-19

NEP [W/√Hz](approximate value)

10-15

Requirements to Detectors⚫ Sensitive to THz photons
Matsuo and Ezawa, JLTP (2016)– Photon energy ~10-21 Joule⚫ Fast responsen/n = 3– B = 1 GHz for 100 M photons/s⚫ NEP(Noise Equivalent Power)= 10-21 × (1 GHz)0.5~ 10-17 W/Hz0.5

OurTargetSPICA

Long Baseline Intensity
Interferometry• Cryogenics - AKARI, SPICA, Astro-H• VLBI technology - HALCA, Astro-G• Superconducting detectors - SMILES
RecorderB > 1GHzRecorderB > 1GHz

Calculate correlation and delay

可能なパラメータ• 望遠鏡口径– 5-10 m, Cryogenic telescopes– Origins, Millimetron• 波長帯– 10 mm – 300 mm, Far-IR, THz– Photon counting detectors• 基線長– 100 m – 100 km, VLBI technology• 角度分解能– 1 marcsec – 10 marcsec, imaging stars and planetsAngular Scale of Observation
All Sky

3°10″

10 mas

10 mas

910111213Log Frequency [Hz]14