Nuclear	  starbursts	  and	  AGN	  fueling	  -­‐	  IR	  view	  -­‐	  Masa Imanishi(Subaru Telescope/NAOJ)	

ALMA AGN workshop	

2015 Dec 21	

Outline	
1. Our IR study
2. Related IR study
3. Implication
4. Unknowns and future work

Nuclear starbursts in the AGN torus
Sy1	  Dusty AGN torus is molecular gas rich
Sy2	  SMBH	

Nuclear starbursts may occur(Fabian+98, Wada+02, +09)

Outer	  part	  of	  the	  torus	  	  	  Gravita8onally	  more	  unstable	  Q = σ κ / π G Σgas	
Keplerian : κ ∝ r −1.5	
Flat : κ ∝ r −1	

Kishimoto+11,+09; Fritz+06: Σ(dust) ∝ r 0 ~ r -1	

Inflated dusty/molecular torus by nuclear SB	
0.2 LEdd	

0.4Myr	0	1.6Myr	

2.0Myr	

15pc	
Time evolution	

Schartmann+14 MN 445 3878 	(see also Wada12 ApJ 758 66) 	

Nuclear	  starbursts	  in	  the	  torus	  NGC1068	  Le Floch+01

Mason+07	

>100pc	  -­‐	  kpc	  scale	  ring-­‐shaped	  	  circumnuclear	  starbursts	  	  	  NGC1097	

NGC7469	
1” = 300 pc	

1” = 80 pc	

Diaz-Santos+07	

Nuclear	  starbursts	  :	  <several	  10	  pc	  (<	  1”	  at	  z	  >	  0.01)	  Slit	  spectroscopy	  Infrared	  3-­‐4	  um	  (L-­‐band)spectroscopy	  1: 3.3um PAH from starburst (not AGN)
Excellent	  probe	  for	  starburst	  PAH	  PAH	  PAH	  2: PAH is intrinsically strong (EW~0.1um)
Weak	  starburst	  detectable	  Infrared	  3-­‐4	  um	  (L-­‐band)	  spectroscopy	  	  3: Low dust extinction (0.03-0.04Av)
Nishiyama+08,09	

L(SB)	  from	  OBSERVED	  PAH	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  ||	  L(SB)	  from	  Av-­‐corrected	  UV	  For	  3	  Sy2s	  (Imanishi	  2002	  ApJ	  569	  44)	  Starbust luminosity is quantifiable
4: More sensitive than N-band (8-13um)

Observations
Infrared 3-4um (L-band) slit spectroscopy of• 32 Sy2s and 23 Sy1s (moderate-luminosity AGN)
• 30 PG QSOs (high-luminosity type-1 AGN)	  Subaru 8.2m/IRCS, IRTF 3m/SpeX

Flux (Fλ)	

Sy2s	  EW~0.1um

EW~0.01um

PAH
detected(11/32)

λ (µm)	
PAH non-detected (21/32)
Imanishi 2003 ApJ 599 918

Flux (Fλ)	

Sy1s	  EW~0.01um

EW~0.01um

PAHdetected(10/23)

λ (µm)	
PAH non-detected (13/23)
Imanishi & Wada 2004
ApJ 617 214

Origin	  of	  nuclear	  PAH	  emission	  	  • AGN / Old bulge stars (central regions)no PAH• Disk star-formation / Nuclear starbursts
Surface brightness:
PAH > 20*1039 [ergs s-1 kpc-2]
IR> 20*1042Starbursts	  PAH emission is of nuclear starbursts origin

Results	  	  !	  rest EW(3.3 PAH)<< 0.1 um

Observed nuclear 3-4 um fluxes aredominated by AGN (not starbursts)!	  L(3.3 PAH)/L(IR) << 10-3

Nuclear starbursts contributelittle to L(IR) of Seyferts

Nuclear starburst luminosity
Sy2 = Sy1 or Sy2 > Sy1 (?)
Starburst

inflate torus

L(3.3 PAH)
= nuclear starburst(Wada+02, Levenson+02)

IRAS 12um, 25um = AGN power

Sy2

L(3.3 PAH)
= nuclear starburst

Gorjian+04	  Imanishi & Wada 2004
ApJ 617 214

Nuclear N-band, radio core = AGN power

Main	  results	  (Moderate	  luminosity	  AGNs)	  L(nuclear SB) : Sy1 ~ Sy2Scenario of L(nuclear SB) : Sy2 > Sy1
Not supported	L(nuclear SB) and L(AGN) : correlated

Physical connection ?	
Nuclear SB is energetically not dominant,but physically close to AGN	PG	  QSOs	  (high-­‐luminosity	  type-­‐1	  AGN)	  PAH detected(5/30)

Composite of no-PAH
sources (Subaru/IRCS)
Imanishi+11 PASJ 63 S447	

PAH non-detected(25/30)L(3.3 PAH)
= nuclear starburst

AGN – nuclear SB connections
in a wide AGN luminosity range	

Nuclear L- or N-band = AGN power
Imanishi+11 PASJ 63 S447	MIR 8-13um (N-band) spectroscopy	

11.3um PAH	

7	L(AGN)	

Esquej+14 ApJ 780 86	

13 um	
L(nuclear SB)	

Nuclear SB vs extended SB	
Nuclear SB : strongly correlated with L(AGN)	
L(AGN)/L(Edd)	

Extended SB:
weakly correlated	

L(SB)	

Watabe+08 ApJ 677 895	Strong correlation	

L(AGN)	

L(extended SB) 	

L(compact SB) 	

Nuclear SB vs extended SB	
Weak correlation	

L(AGN)	
Diamond Stanic+12 ApJ 746 168

NIR H- (1.65um) and K-(2.2um) spectroscopy	
Davies+07 ApJ 671 1388 	

Fλ	Stellar CO abs. feature	1.65 um	

L(AGN)

1.55	

Time delay between
nuclear SB and AGN ?
(SB regulate AGN)	

assumed	

SB age	Nuclear SB regulates L(AGN) ?	
Nuclear SB inflates
outer dusty tori
(due to energy input)

Mgas(<1pc)	

Wada+02 ApJ 566 L21
Wada+09 ApJ 702 63	

Gas accretion onto SMBH
increases by nuclear SBat outer dusty tori 	

Time (Myr)	

Q: Do we indeed understand torus?	

Fν（mJy）	

Fit nuclear MIR emission with clumpy torus model 	1	10	(um)	 100	Torus size = 1-6pc	
Ramos Almeida+14
MN 439 3847 	

Alonso-Hererro+11
ApJ 736 82	

VLTI: MIR 10um emission is compact	NGC 1068	

Circinus	~3pc	

Jaffe+04 Nature 429 47	

Tristram+07 AA 474 837	Inflated dusty/molecular torus by nuclear SB	
0.2 LEdd	

0.4Myr	0	1.6Myr	

2.0Myr	

15pc	
Time evolution	

Torus size = 10-20 pc	

Schartmann+14	
(see also Wada12)	

50-100 pc scale thick molecular gas	NIR 2um IFU (H2 line)	

dispersion	

velocity	

200 pc	

NGC 7743	

High σ/v at 50-100 pc	

Davies+14 ApJ 792 101	Dust and molecular gas usually coexist	
Inflated dust at 50-100 pc ?	

10um emission probes hot (~300K) dust 	
Smaller than the actual torus outer radius?	
Shorter λ	9.7um	

compact	

12.0um	30.2um	Schartmann+08
AA 482 67 	

ALMA high-spatial-resolution 350um image	
Garcia-Burillo+14
AA 567 A125

0.3-0.5”	

NGC 1068	

No discrete torus
emission at 350um
Even higher
resolution help?	
Veiled by extended
cool dust emission?	
Need 20-30um?	

Nuclear MIR emission = torus origin ?	
NGC 1068	
12.5um	cone	Circinus	
11um	

torus	

Jaffe+04 Nature 429 47	

Tristram+07 AA 474 837	Origin of nuclear MIR emission	
0°	

Schartmann+14	30°	60°	

90°	12um	

500um	At 12um,
torus is darkcone is bright

10um/20um flux ratio	
20um obs
TMT/MICHI ?	

TMT 30m + MICHI 10,20um	

PI:Packham	

UKIRT/UIST : 3-4um (L-band) IFU	
Seeing-limited 3.3um PAH map of>100 pc-scale circumnuclear SB	
1.5∆dec [arcsec]

10.5
0

1.5
NGC16142.51(z=0.01620.564Mpc)	
0
1.5

−0.5
1−1−1.5
210∆RA [arcsec]−1−23.3um PAH EW	
EW map: 3.3 µm PAH [nm]−16x 10∆dec [arcsec]

3.3um PAH flux	

Integrated (3.3 µm - continuum) [W/m2 /arcsec2 ]Vaisanen+12
MN 420 2209 	

80706050−0.540−1301” ~ 300pc−1.5	20210∆RA [arcsec]−1−2High-spatial-resolution, AO-assisted, 3-4um IFU is ideal	No such instrument in the world	
UKIRT/UIST decommissioned	
TMT 30m has no 3-4um (L-band) instrument	

TMT MICHI	IFU at 10um (N-band)to study 11.3um PAH

11.3PAH	
3.3PAH	

0.08” resolution	
L	IFU	N	
Sturm+00	

ALMA spatially-resolved molecular line
flux ratios in very nearby AGN	
Viti+14 AA 570 A28	0.6” x 0.5”	

NGC 1068	

Higher-spatial-resolution?	

A reliable uniquemodel needed	Summary	
AGN fueling could be explained by
AGN – nuclear starburst connection 	but	
Essential parts are still far from complete
understanding	
TMT/MICHI + ALMA may be powerful	
AGN regulate nuclear SB ?	
Nuclear SB regulate AGN?	

End