subaru ao high spatial resolution ir k and l band search for buried dual agns in merging galaxies n.
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Subaru AO high-spatial-resolution IR K- and L-band search for buried dual AGNs in merging galaxies

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Subaru AO high-spatial-resolution IR K- and L-band search for buried dual AGNs in merging galaxies

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  1. Subaru AO high-spatial-resolution IR K- and L-band search for buried dual AGNs in merging galaxies Masatoshi Imanishi (今西昌俊) NAOJ/Subaru Telescope Imanishi+14 ApJ 780 106

  2. Simulation (Kazantzidis) CDM galaxy formation: Gas-rich galaxy mergers common in the universe HST image

  3. Supermassive blackhole (SMBH) ubiquitous at galaxy center Gultekin+09 SMBH mass SMBH mass bulge mass NASA Multiple SMBHs common in mergers bulge mass Many dual AGNs expected, if SMBHs are active

  4. Double-peaked optical emission lines [OIII] 4959 [OIII] 5007 Dual AGN Hβ outflow jet interaction Two discrete line emitting clouds ~1%(87 / 6780 z<0.15 type-2 AGN) See also Liu+10,11, Smith+10, Pilyugin+12, Ge+12,Barrows+13 Wang+09 ApJ 705 L76

  5. Follow-up of double-peaked lines objects Fu+11b ApJ 733 103 Keck II/OSIRIS+LGS-AO H-band 10” ~30%(16/50) double nuclei Dual AGNs not required in the majority (~70%) (Jet-cloud interaction etc)

  6. Very small (<1%) dual AGN fraction in double-peaked lines dual AGN search • miss face-on SMBHs Edge-on:OK Face-on: undetectable • Buried AGNs undetectable Need observations at wavelengths of low dust extinction

  7. High-spatial-resolution imaging Sensitive to face-on multiple SMBH with small separation • radio (VLBI) Burke-Spolaor11 Miss the majority of radio-quiet AGN • X-ray 2-10 keV (Chandra; 0.5”) Miss Compton-thick (NH > 1024 cm-2) AGNs Teng+05,09,12,Iwasawa+11a,11b, Koss+12,Liu+13

  8. Our method: Subaru AO infrared imaging • Infrared K (2.2um) and L’(3.8um) Sensitive to buried AGNs, including radio-quiet ones • Subaru-AO (0.1-0.15”) Sensitive to small separation (face-on) dual AGNs at late merging stage

  9. AKARI 2.5-5um spectroscopy Imanishi+10 ApJ 721 1233 PAH Normal starbust Buried AGN Buried AGN: K-L red (~2 mag) Starburst: K-L blue (~0.5 mag) (AGN heated hot dust emission)

  10. AGN (red K-L nucleus) 28/29 (U)LIRGs show at least one AGN 10” Imanishi+14 ApJ 780 106

  11. Dual AGNs (two red K-L nuclei) 4/29 (U)LIRGs 10” Imanishi+14 ApJ 780 106

  12. Subaru AO L’(3.8um) (0.1-0.2”) Spitzer IRAC 3.6um (1”/pix) WISE 3.4um >5”

  13. Small fraction (15%) of IR buried dual AGN 1. Dust obscuration ? 2. Orbiting geometry ? 3. Non-simultaneous SMBH activation

  14. More massive SMBH is more actively mass accreting (=high Eddington ratio) AGN luminosity ratio between two nuclei Less massive SMBH has high Eddington ratio SMBH mass ratio between two nuclei Imanishi+14 ApJ 780 106

  15. Non-simultaneous SMBH activation throughout the merging phase More massive SMBH has higher Eddington ratio Imanishi+14 ApJ 780 106

  16. Summary Our Infrared K- and L-band AO imaging revealed non-simultaneous SMBH activation Even if two SMBHs are present, only one SMBH can become sufficiently luminous to be detectable as an AGN More massive SMBHs have higher Eddington ratio Can explain the observed small dual AGN fraction in merging galaxies

  17. Summary 2 SMBH activation is dominated by local conditions, rather than global galaxy properties Difficult to predict by simulation Need observational constraints Imanishi+14 ApJ 780 106

  18. End

  19. Buried AGN Lν(3-4μm) (intrinsic) = L(AGN) ν