1. Subaru and Gemini high-spatial-resolution 20um imaging of nearby LIRGs
Masa Imanishi
（今西　昌俊）
NAOJ (Subaru Telescope)
Subaru
Gemini-S

2. ULIRGs:>1012Lo Luminous infrared galaxies（LIRGs） L(IR) > 1011 Lo
(Normal spiral ~ 1010 Lo)
optical IR
(U)LIRGs IR
optical
M100（Sbc）
Luminous energy source is hidden behind dust

3. (U)LIRGs Luminous energy sources behind dust > 10kpc
L(IR) > 1011Lo
Luminous energy sources behind dust
Starburst
> 10kpc
AGN
Mass accretion onto
supermassive
blackholes（>106 Mo）
< 1pc

4. (U)LIRGs: important at high-z
Caputi et al. 2007 2
ULIRG
LIRG 1
ULIRG
Le Floc’h et al. 2005
LIRG 1
LIRG
ULIRG

5. AGNs in (U)LIRGs are buried
Veilleux+99
Sy2
NLR
AGNs obscured by
torus-shaped dust
HII LI
Sy2
Detectable via optical spectroscopy
(U)LIRGs have a large amount
of nuclear gas and dust
Buried AGNs are elusive
>70% (U)LIRGs = non-Sy
Veilleux+99;Yuan+10

6. IR spectroscopy AKARI 2.5-5um Normal SB Buried AGN ★ Extreme SB (?)
PAH
Normal SB
Buried AGN
AGN ★ SB
Extreme SB (?)

7. ★ Thompson+05 Emission surface brightness Buried AGN E = 6-40% Mc2 SB
>>1013 Lo / kpc2
M82 SB
1011 Lo / kpc2
<1013 Lo / kpc2
M42
HII-region core
Supported by
Eddington-limited
SB theory
Thompson+05

8. If >>1013 Lo / kpc2, then buried AGN
Ground-based large 8-10m telescope
is better than space satellites ( m)
PAH contamination
small
Diffraction-limited image achieved
Stable PSF
Why 20um?

9. Imanishi+11 Subaru COMICS Diffraction-limited images
are usually achieved
20um
compact
extended
Standard star
size<0.2”
1012 Lo / kpc2
Mitsubishi-
pattern
>3*1013 Lo / kpc2
Imanishi+11

10. Imanishi+11 Gemini-S/T-ReCS Diffraction-limited images
are usually achieved
20um
extended
Standard star
compact
<1012 Lo / kpc2
size<0.25”
Diffraction
ring
>2*1013 Lo / kpc2
Imanishi+11

11. Super star cluster NGC 5253 (d=4Mpc) Gemini-S T-ReCS 20um
~1013 Lo / kpc2
Imanishi+11 submitted

12. IR spectroscopy vs imaging (I)
(z=0.016)
extended SB
~1012 Lo / kpc2
(z=0.025)

13. IR spectroscopy vs imaging (II)
B-AGN
(z=0.058)
compact
>1013 Lo / kpc2
(z=0.055)

14. Distant ULIRGs (z>0.1)
>0.5*1013 Lo/kpc2
Need higher-spatial-resolution of TMT/MICHI

15. Summary Imanishi+11 submitted (accepted soon)
B-AGN and SB are distinguishable, based on
20um emission surface brightness, if z < 0.06
Generally agree with IR spectroscopic
energy diagnostic method
Imanishi+11 submitted (accepted soon)

16. End