260 likes | 501 Views
Spitzer. AKARI. AGN-starburst connections. AKARI infrared 2-5um spectroscopy of nearby luminous infrared galaxies. Subaru Telescope/NAOJ. Masa Imanishi. 2012 Feb 28 Second AKARI conference. optical. (U)LIRGs. IR. IR. optical. Luminous energy source is hidden behind dust.
E N D
Spitzer AKARI AGN-starburst connections AKARI infrared 2-5um spectroscopy of nearby luminous infrared galaxies Subaru Telescope/NAOJ Masa Imanishi 2012 Feb 28 Second AKARI conference
optical (U)LIRGs IR IR optical Luminous energy source is hidden behind dust Luminous infrared galaxies(LIRGs) Sanders & Mirabel 96 L(IR) > 1011 Lo ULIRGs:>1012Lo M100(Sbc) (Normal spiral ~ 1010 Lo)
> kpc Starburst AGN Mass accretion onto supermassive blackholes(>106 Mo) < 1pc LIRGs : LIR>1011Lo ULIRGs : >1012Lo Luminous energy sources behind dust
NLR (U)LIRGs have a large amount of nuclear gas and dust Buried AGNs are elusive >70% (U)LIRGs = non-Sy Veilleux+99 AGNs in (U)LIRGs are buried Sy2 AGNs obscured by torus-shaped dust HII LI Sy2 Detectable via optical spectroscopy Hopkins+06 Veilleux+99;Yuan+10
Buried AGN AGN+SB Starburst(SB) featureless 3.3um PAH EW(PAH)<<100nm EW(PAH)~100nm 3.4um/3.1um 1. Infrared spectral shape PAH PAHs are excited in starburst PDRs but destroyed near an AGN
(U)LIRG core <500pc Mixed dust model Foreground screen dustmodel 1-exp(-Tau) exp(-Tau) Tau Dust absorption feature: weak strong (Imanishi+06,07) 2. Dust absorption feature strength starburst Buried AGN
2.5-5 um AKARI z<0.3 ULIRG Buried AGN AGN+SB SB PAH 3.3um Bare 3.4um PAH 3.3um Bare 3.4um Ice 3.1um PAH strong (SB): Dust abs. weak PAH weak (AGN): Dust abs. strong wavelength Imanishi+08,10b
Spitzer z<0.3 ULIRG 5-35 um AGN+SB SB Buried AGN PAH PAH 18um 18um 9.7um 9.7um 9.7um PAH PAH 18um 18um 9.7um 9.7um 9.7um PAH strong: Silicate Abs. weak PAH weak: Silicate Abs. strong wavelength Imanishi+07,09,10a
LIRG(<1012 Lo) (spatially extended) AKARI SB 2.5-5 um slitless spectroscopy Buried AGN Seyfert Imanishi+10b wavelength
Buried AGNs (B-AGN) increase with LIR LIRG B-AGN fraction ULIRG L(IR) Results nearby(z<0.3) >130 sources Opical non-Seyfert (U)LIRGs Luminous buried AGNs >30% Optical non-Sy (U)LIRGs only
B-AGN luminosity (extinction-corrected) ~10-50% of L(IR) L(B-AGN) L(IR)
SFR AGN/SB SB B-AGN L(IR) B-AGN vs SB connections are luminosity dependent see also Nardini+10 low M(star) high M(star)
z=0 Big bang AGN weak B-AGN Galaxy down-sizing More massive galaxies have finished major SF at higher-z Cowie+96 Link (?) high-z low-z Luminosity-dependent B-AGN - SB connections
Summary Buried AGNs are common in non-Sy LIRGs B-AGN vs SB connections are L-dependent Imanishi+08 PASJ 60 S489 (AKARI) Imanishi+10b ApJ 721 1233 (AKARI2) Imanishi+07 ApJS 171 72 (Spitzer) Imanishi 09 ApJ 694 751 (Spitzer2) Imanishi+10a ApJ 709 801 (Spitzer3)
AKARI 2.5-5um 3. Continuum slope SB unobscured AGN obscured AGN
L(PAH-derived SB) ~10-100% of L(IR) L(SB) from PAH L11.3PAH L(IR)
3.3PAH Brα SFR(Brα) SFR(3.3PAH) PAH = good SB indicator SFR(Brα) ~ SFR(3.3PAH) A3.3PAH = Av/30 Nishiyama+09 A3.3PAH < 1 mag for Av < 30 mag Imanishi+10b
LIRG(<1012 Lo) (spatially extended) AKARI SB 2.5-5 um slitless spectroscopy Buried AGN Seyfert Imanishi+10b wavelength
★ SB Possibility of extreme SB ? Exceptionally centrally-concentrated SB HII-region only (no PDRs, no molecular gas)
Buried AGN E = 6-40% Mc^2 >>10^13 Lo/kpc^2 10^11 Lo/kpc^2 <10^13 Lo/kpc^2 M42 M82 SB HII-region core Emission surface brightness SB ★ SB E = 0.5% Mc^2
SB : < 10^13 Lo/kpc^2 Supported by theory Eddington-limited SB At T<150K, <10^13Lo/kpc^2 Tcolor of ULIRGs = 60-80K Thompson et al. 2005
z<0.15 ULIRG Subaru 3-4 um Buried AGN AGN+SB SB PAH 3.3um Bare 3.4um PAH 3.3um Ice 3.1um Bare 3.4um PAH strong (SB): Dust abs. weak PAH weak (AGN): Dust abs. strong wavelength Imanishi+06
2.5-5 um z>0.15 ULIRG AKARI SB AGN+SB PAH strong (SB): Dust abs. weak PAH weak (AGN): Dust abs. strong wavelength Imanishi+08
starburst (extended) ULIRG (compact) (z=0.058) 10^12Lo/kpc^2 size<0.2” >10^14Lo/kpc^2 Subaru COMICS Diffraction-limited images are usually achieved 20um Standard star Mitsubishi- patten