sub-mm vlbi for resolving super-massive black hole mareki honma vera / mizusawa vlbi observatory,...
TRANSCRIPT
sub-mm VLBI for resolving super-massive black hole
Mareki Honma
VERA / Mizusawa VLBI observatory, NAOJ
Target : touching the event horizons of BHs
Fukue et al 1989
•AGN core is most-likely a super-massive black hole.
•Yet, there is no confirmation of existence of event horizon
Direct detection of BH shadow is an ultimate confirmation of existence of BH. (or negative results may indicate an existence of naked singularity !?)
•New breakthrough for experimental BH physics!?
BH size
source MBH/Msun DistanceAngular
radius
Sgr A* 4 x 10^6 8 kpc 10μas
M87 3 ~ 6 x 10^9 15 Mpc 4 ~ 7μas
M104 1 x 10^9 10 Mpc 2μas
Cen A 5 x 10^7 4 Mpc 0.25μas
Shadow diameter : 1~5 times Schwartshild radiusFor imaging shadow, ~ 10μas resolution is required
Angular resolution of telescopes• Wavelength – angular resolution diagram
VSOP-2
VLBA
VERA ALMA
AKARI
SUBARUHST
cm wave IR opticalmm wave
VLBIConnectedarray
Single dish
Res
olut
ion
in m
as
λ
1 mas
1 arcsec
Submm VLBISgr A* BH size
Doeleman+(2008)
・ 37±(16,10) Intrinsic diameter of Sgr A* ・ Non detection on the JCMT-CARMA ( 3075 km )
ARO/SMT - CARMA(600km)
ARO/SMT - JCMT
Non-imaging analysis (traditional UV distance plot)
• 230GHz VLBI with JCMT – SMTO – CARMA
Sub-mm VLBI of Sgr A*
1995 Mar IRAM30m-PdB Krichbaum+ (1998)
…
2006 Mar Hawaii-SMTO-CARMA failed
2007 Mar JCMT-SMTO-CARMA Doeleman+(2008)
but IRAM/PdB failed
2009 Mar Hawaii-SMTO-CARMA
SMA phase-up Fish+(2011)
2010 Mar Hawaii-SMTO-ASTE
2011 Mar Hawaii-SMTO-CARMA-APEX-IRAM
but not fringes from Chile and Europe …
Sub-mm VLBI with ASTE (2010)Chilean station will be a key for Sgr A* observations
good site & longest baselines
JCMT
CARMA
ASTE
SMTO
UV coverage for Sgr A*( red: UV with ASTE )fringe spacing ~30μas
Sub-mm VLBI in 2011 Mar/Apr
International campaign from Mar. 28 to Apr. 5
Hawaii
CARMASMTO
(APEX)
(Pico Veleta)
Planned Array for April 2011 obs.
US array (Hawaii-CARMA-SMTO) is the coreEuropean stations may join (APEX / IRAM 30m)
Steps toward future• Re-trial with Chilean stations (ASTE/APEX) ?• Green land (ASIAA) : ALMA prototype move in 2013 ?• LMT : VLBI capability ?
• ALMA phase-up is the key (both sensitivity & imaging capability)
Proposal to NSF MRI in 2011
Haystack/ NRAO/ MPI/ NAOJ/ ASIAA etc.
Highly-ranked by NSF review and
will be funded this year.
observation from ~2015 (?)• Large (sub-)mm telescope will be very
useful.
ALMA phase-up plan• Phased-sum in
baseline correlator
data transfer to OSF
& recording there
• Japan’s part :
optical-fiber transmission
between ALMA – OSF
OSF(@2900m)
Optical fiber (8 x 8Gbps)
Correlator (sum-up)
Science cases• BH shadows : Sgr A* & M87• Jet monitor: launch/accelaration mechanism• Detailed structure of accretion disk• Time variation (Sgr A*: 15min, M87 : a few days)
of structure near BH• Rotation of hot spot/disk patch > test of General
Relativity in strong gravity field.
+ non-BH sciences
SFR/AGB masers, astrometry
(LMC/SMC, for instance)
M87 at 43G
BH simulationGammie & Noble
New laboratory for “Black Hole Physics”
Discriminating models for M87• Simple simulations how ALMA works out
Ring between 15.0 - 25.5μas Gaussian with 13.0-μas-
radius shadow
Gaussian with 38μas FWHM Disk with 30μas radius
Chilebaselines
Simulated and observedvisibilities vs. UV distance
Chilebaselines
γ-ray emitting AGNs• Example : 3C84, radio jet detection (VERA) after
γ-ray flare (Fermi)
Radio light curve
VLBI map (2 x 2 pc), at 22 GHz
Nagai+(2010)
cm + (sub-)mm VLBI will lead comprehensive understanding (higher resolution & lower optical depth …)
SSC modelfor Mrk 501(Kino+2001)
γ-ray mittingregion:<1000 AU
Science cases around 2020Basic assumption : BH shadow itself is already seen
•Jet monitor: launch/accelaration mechanism
•Detailed structure of accretion disk
•Time variation (Sgr A*: 15min, M87 : a few days)
of structure near BH
•Rotation of hot spot/disk patch > test of General
Relativity in strong gravity field.
M87 at 43G
BH simulationGammie & NobleNew laboratory for “Black Hole Physics”
role of new large telescope in Chile in VLBI
• Even if ALMA phase-up goes, machine time should be very limited (machine time is very important, e.g., for monitor). 50m(?) in Chile will expand possibility of doing VLBI.
• Combination of 50m in Chile and phase-up ALMA (50 of 12-m) equivalent to 98-m dish !!
• 50m-ALMA for short baseline obs. (30 km – 100 km?)
Providing new “longest” baseline for ALMA
> additional science cases, such as resolving nearby giant stars
Summary• Sub-mm VLBI will open up wonderful science
cases with ultra-high resolution:
resolving BH shadows, Jet launching / gamma-ray-jet connection and more…
• Large (sub-)mm telescope will be useful to expand science cases with sub-mm VLBI (e.g., monitor etc.)