agn science with ska motoki kino (naoj) on behalf of ska-japan agn sub-wg japan-ska workshop (nov. 5...
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AGN Science with SKAAGN Science with SKA
Motoki Kino (NAOJ)On behalf of SKA-Japan AGN sub-WG
Japan-SKA workshop (Nov. 5th 2010, NAOJ)
(C) J. McKean
Cygnus A at 240 MHz with LOFAR
MembersN. Kawakatu (Tsukuba Univ., Representative)M. Kino (NAOJ, Jr. Representative) T. Kawaguchi (Tsukuba Univ.)H. Nagai (ISAS/JAXA) H. Ito (Tohoku Univ.)S. Kameno (Kagoshima Univ.) A. Doi (ISAS/JAXA)M. Imanishi (NAOJ/Subaru) M.Umemura (Tsukuba Univ.)
Outline 1.Why AGN with SKA?2.AGN outflow3.AGN inflow4.Summary
Because it will have VLBI-order resolution (D~3000km) with sub-μ Jy revel sensitivity!
Why AGN with SKA?
Points can be summarized into the following two concepts:
1. Filling the gap between VLBIs and VLA
2. Quest for very faint radio emission
- kpc jets- Cocoons- Radio-quit AGNs
Kino, Nagai, Ito, Kawakatu
Internal Structure in shocks@kpc?
3C380, VLA 15GHzKoyama, MK+ in prep
In general, it is not easy to see knots by current VLBI’s sensitivity.
Beyond 1-zone: K1 = compact + diffuse region? ⇒ SKA@mid/high-band => Particle acceleration
1 arcsec=6.9 kpc
Very few reports on jet motions at ~kpc. ⇒ SKA@high-band => Relativistic Hydrodynamics
10 pc150 kpc
VLBIs see only here.
It is very difficult to detect motions at kpc jets by VLBIs/VLA.
Low Energy Electrons
SKA-low band will show us a new world of radio cocoon.=> True total power of jets (MK+05, Ito+08)
Low-energy-electrons tell us the true shape of jet-remnants (not lobes but a cocoon) because of its longer cooling time.
(C) J. McKean
“Radio-quiet” is really radio-quiet?
Observations of “radio-quiet” populations have been started (ex. Narrow Line Seyfert 1 galaxies)
SKA’s sensitivity will allow us to detect weak radio emission from currently “radio-quiet” AGNs.=>Hint for underdeveloped jets?
By Japanese VLBI Network@8GHz
-Imaging Accretion Disk-Corona-Quest for AGNs in ULIRGs/BCDs
Kawakatu, Kawaguchi, Imanishi, Umemura, Doi, Kameno, Hirashita
9 10 11 12 13 14 15 16 17 18 19
38 Log ν [Hz]
Disk black body
- Size : ~ 300 Rs - Brightness temperature: Tb ~109K for ν < 20GHz- Targets : Nearby Seyferts
Imaging Accretion Disk-Corona
Higher freq. is preferable to resolve it. ⇒ SKA@high-band
AGN or Star-Burst in ULIRGs? Which is the energy source of ULIRGs ?Luminous energy sources behind dust @z <0.1
AGN: compact Star-Burst: extended
High surface brightness radio core emission = AGN
IR-spectroscopy study (Imanishi+06,07,08,09)
Observations with high spatial resolution avoiding free-free absorption are required. ⇒ SKA@high-band
AGNs in Blue Compact Dwarfs?
II ZW 40 (age ~ 3Myr)
Hirashita & Sakamoto (in preparation)
Star burst (Free-free)
Spectral index is the key to distinguish them. ⇒ SKA@mid-band frequency (1-15 GHz)
1. AGN outflow- kpc scale jets- Radio Bubbles: Super-sonic or sub-sonic?- Cocoons - “Radio-quiet” AGNs
2. AGN inflow- Imaging nearby Accretion Disk-Corona- Quest for AGNs at the core of ULIRGs - Quest for AGNs at the core of BCDs