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sub-mm VLBI for resolving super-massive black hole

sub-mm VLBI for resolving super-massive black hole. Mareki Honma VERA / Mizusawa VLBI observatory, NAOJ. Target : touching the event horizons of BHs. AGN core is most-likely a super-massive black hole. Yet, there is no confirmation of existence of event horizon

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sub-mm VLBI for resolving super-massive black hole

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  1. sub-mm VLBI for resolving super-massive black hole Mareki Honma VERA / Mizusawa VLBI observatory, NAOJ

  2. Target : touching the event horizons of BHs • 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!? Fukue et al 1989

  3. BH size Shadow diameter : 1~5times Schwartshild radius For imaging shadow, ~ 10μas resolution is required

  4. Angular resolution of telescopes IR cm wave mm wave optical • Wavelength – angular resolution diagram AKARI 1arcsec Connected array HST Resolution in mas VLBI SUBARU Single dish ALMA VERA 1 mas VLBA VSOP-2 Submm VLBI Sgr A* BH size λ

  5. ARO/SMT－CARMA(600km) ARO/SMT－JCMT Doeleman+(2008) • 230GHz VLBI with JCMT – SMTO – CARMA Non-imaging analysis (traditional UV distance plot) ･ 37±(16,10)Intrinsic diameter of Sgr A* ･ NondetectionontheJCMT-CARMA（3075 km）

  6. 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 …

  7. SMTO CARMA JCMT ASTE Sub-mm VLBI with ASTE (2010) Chilean station will be a key for Sgr A* observations good site & longest baselines UV coverage for Sgr A* （red: UV with ASTE） fringe spacing ~30μas

  8. Sub-mm VLBI in 2011 Mar/Apr International campaign from Mar. 28 to Apr. 5 CARMA SMTO (Pico Veleta) Hawaii (APEX) Planned Array for April 2011 obs. US array (Hawaii-CARMA-SMTO) is the core European stations may join (APEX / IRAM 30m)

  9. 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.

  10. ALMA phase-up plan • Phased-sum in baseline correlator data transfer to OSF & recording there • Japan’s part : optical-fiber transmission between ALMA – OSF Optical fiber (8 x 8Gbps) Correlator (sum-up) OSF(@2900m)

  11. 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 New laboratory for “Black Hole Physics” BH simulation Gammie & Noble

  12. Discriminating models for M87 Gaussian with 13.0-μas- radius shadow • Simple simulations how ALMA works out Ring between 15.0 - 25.5μas Simulated and observed visibilities vs. UV distance Chile baselines Chile baselines Gaussian with 38μas FWHM Disk with 30μas radius

  13. γ-ray emitting AGNs VLBI map (2 x 2 pc), at 22 GHz Nagai+(2010) • Example : 3C84, radio jet detection (VERA) after γ-ray flare (Fermi) Radio light curve SSC model for Mrk 501 (Kino+2001) γ-ray mitting region:<1000 AU cm + (sub-)mm VLBI will lead comprehensive understanding (higher resolution & lower optical depth …)

  14. Science cases around 2020 Basic 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 simulation Gammie & Noble New laboratory for “Black Hole Physics”

  15. 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

  16. 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.)

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