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!

Wilkinson 2004

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

AGN outflow

- kpc jets- Cocoons- Radio-quit AGNs

Kino, Nagai, Ito, Kawakatu

Internal Structure in shocks@kpc?

O’dea+98

3C380, VLA 15GHzKoyama, MK+ in prep

In general, it is not easy to see knots by current VLBI’s sensitivity.

core

K1

730 mas

VLBA+Y1, 1.4GHz

B amplified!?

Beyond 1-zone: K1 = compact + diffuse region? ⇒ SKA@mid/high-band => Particle acceleration

2kpc

1 arcsec=6.9 kpc

Very few reports on jet motions at ~kpc. ⇒ SKA@high-band => Relativistic Hydrodynamics

10 pc150 kpc

Krichbaum+

Motion@kpc?

VLBIs see only here.

Cygnus A

It is very difficult to detect motions at kpc jets by VLBIs/VLA.

Yaji+ 2010

Low Energy Electrons

SKA-low band will show us a new world of radio cocoon.=> True total power of jets (MK+05, Ito+08)

Chandra+VLA@330MHz

Low-energy-electrons tell us the true shape of jet-remnants (not lobes but a cocoon) because of its longer cooling time.

VLA@5GHz

LOFAR@240MHz

(C) J. McKean

“Radio-quiet” is really radio-quiet?

Observations of “radio-quiet” populations have been started (ex. Narrow Line Seyfert 1 galaxies)

Doi+ 2007

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

AGN inflow

-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

46

45 44

43 42

41

40

39

38 Log ν [Hz]

bremsstrahlung

Disk black body

Cyc-syn emission

- Size : ~ 300 Rs - Brightness temperature: Tb ~109K for ν < 20GHz- Targets : Nearby Seyferts

* ~20GHz

Log

νL

ν [e

rg/s

]

SKA

Kawaguchi +01

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

★AGN SB

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)

VLA(3-4’’)SMA (5’’)

Hirashita & Sakamoto (in preparation)

Free-Free

AGN (RIAF)ν1/3

Star burst (Free-free)

ν-0.1

SKA

0.6

VLA(0.1”): 　Beck+02

metal poor　

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

Summary