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Super Massive Black Holes

How do cosmic accelerators work and what are they accelerating? What collimates jets and how do jets evolve and interact with their host galaxy?. Super Massive Black Holes. M 87.

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Super Massive Black Holes

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  1. How do cosmic accelerators work and what are they accelerating? What collimates jets and how do jets evolve and interact with their host galaxy? Super Massive Black Holes M 87 • VLBI movies of AGN jets (eg M 87, blazars) provide the only way to image these amazing phenomena on scales down to the ergosphere of nearby SMBHs. • VLBA imaging surveys of >1000 AGNs! No new binary SMBHs found. • Jet acceleration ramps up over inner parsecs. Non-balistic motions common; mm-VLBI jet widths currently favor B-Znajek over B-Paine. Polarization imaging revealing jet-sheaths…extremely rich phenomenology. • “Event Horizon Telescope” VLBI can image with Rsch resolution for Sgr A* and M87; already see dramatic changes on scales of Rsch; phased-ALMA critical Outstanding synergy with Fermi g-ray telescope…same particles produce g-rays also radio photons. While g-rays may dominate energetics, but VLBI can image what’s going on; eg, evidence that SLM traced back to “core”, not BH, at time of optical and g-ray flares

  2. Do SMBHs control galaxy evolution (via AGN feedback)? How do AGN accretion disks work? • Sub-pc resolution imaging of AGN accretion disks via H2O masers (~150 now known) with 3D velocities • “Gold Standard” black hole mass measurements; test and calibrate the MBH-s relation (sM ~ few%) • Seyfert galaxy MBH~ 107 Msun fall below M-s relation • Get physical parameters of accretion disks (possibly to high-z): • limits on disk mass • T ~ 103 K and n ~ 109 cm-3 (to allow masing) • B-fields possible from Zeeman effect • Causes of warps; spiral structure? Super-Massive Black Hole Accretion Disks NGC 4258

  3. How do black holes form and evolve? Did Einstein have the last word on gravity? • VLBI parallaxes (+optical/x-ray data)  accurate binary parameters and BH spins • Directly tracing binary orbits • Some BH’s may form without a bang! • Fermi HMXRB (LSI+61o303) mystery; VLBA cometary-like pulsar-wind nebula, but no pulsations found. g-ray light curve evolving, unlike pulsar. What is going on? Stellar Black Holes Cygnus X-1

  4. What Is the kinematic and spiral structure of the Milky Way? What are the masses of its (disk, bar/bulge, halo) components? • Parallaxes/proper motions of masers in star forming regions will accurately trace spiral structure • Determine fundamental parameters, R0 and Q0 • Nearly 50 high-mass star forming region parallaxes measured with VLBA and VERA • More than ~300 22-GHz H2O and ~1000 6.7-GHz CH3OH masers known…no shortage of sources The Milky Way

  5. How do low mass and massive stars form? How do accretion disks work and drive outflows? • Parallaxes (±1%) of low-mass stars throughout the solar neighborhood; without parallaxes get poor sizes of disks (25%), L and age (50%), mass (100%) • Resolve Pleiades distance controversy (Hipparcos vs. “rest of the world”)…main-seq fitting, stellar ages & evolution • Accurate masses, luminosities and ages of YSOs • Direct imaging of disk outflows with sub-AU resolution and 3D velocity information • OH masers: full Zeeman effect (potential for 3D B-field) • VLBI masers maps synergistic with EVLA & ALMA for high-mass star formation studies Star Formation Orion Source-I

  6. Can the extragalactic distance scale be improved? What is the value of Ho (and then w)? Do fundamental constants change over cosmic time? • Rotational parallaxes (eg, M 33) allow better calibration of Cepheid P-L-metallicity relation • Direct measurement of H0 from megamaser H2O maser (Megamaser Cosmology Project): ~150 known; so far 8 good for distance measurements • Goal: 10 galaxies each with sHo ~ 10%  3% final uncertainty • Ho = 72 ± 5 km/s/Mpc for NGC 4258 (by re-cal’ing Cepheids) • Ho = 69 ± 11 km/s/Mpc for UGC 3789 (directly) • Ho = 73 ± 7 km/s/Mpc for NGC 6264 (directly) • Measuring spectral lines at high redshift test constancy of fine-structure “constant” and proton-electron mass ratio; need highest angular resolution to isolate absorption compnents Cosmological Parameters UGC 3789

  7. How Is matter distributed in the Local Group of galaxies? What is the history and fate of the Milky Way and the Local Group? What happens to SMBHs in merging galaxies? Galaxy Interactions and Mergers • Proper motion measurement of Andromeda is key to the dynamical fate of the Local Group • Measurement of the masses of the dark matter halos of Andromeda and Milky Way • OH megamasers reveal galaxy mergers; maser clumps have dynamical masses of ~106 Msun • No new binary SMBHs found in VLBA survey of over 1100 ANGs!

  8. How do explosions work and what do they make? How do pulsars form, evolve, and emit? What is the equation of state of neutron stars? Physics of Explosions and Ultradense Matter • Distances (parallaxes) to neutron stars are key to determining their masses and radii, which combined can place strong constraints on the equation of state of ultra-dense matter. • Proper motions indicate birth places and ages of pulsars. • With parallax & DMs can model Milky Way ne • Pulsar parallaxes sensitivity limited…need BW • For Fermi pulsars, D => L and comparing L(g-ray) vs. L(spindown), if equal, can get moment of intertia…M(r)

  9. Are planetary systems around low mass stars different from solar mass stars? What is fraction of long-period planets around low mass stars? • RIPL: targets are low-mass nearby stars; can rule out planet >10 MJ @ 1 AU in only 10 days! • Hints of planets in data. • Sensitivity limited…need more BW Exosolar Planets

  10. What is the Earth’s rotation, gravity field and internal structure? What are asteroid shapes and spins? • EOP measured using VLBA & other antennas • VLBI only technique for the fundamental celestial and terrestrial reference fames and UT1 • Quality of VLBA data improved ICRF by 60% ! • Highest precision free-core nutation measures • Measure asteroid spin/shape, using short VLBA baselines, for possible manned “landing” The Earth as a Planet, Solar System & Reference Frames

  11. How well can we locate and track interplanetary space craft? Can we improve the rather uncertain orbits of outer planets? • VLBA positioning complementary to range-Doppler tracking…need VLBI array controlled at 1 location • Demonstrated <1 nrad (<0.2 mas); VLBI is most accurate space craft tracking method • Tracking Cassini improved mass estimate of Iapetus • Measured barycenter of Saturn to ±10 mas • IKAROS (solar-sail) tracked with Australian VLBI • Future can achieve <100 m lateral positioning Space Craft Tracking

  12. What role does the VLBA play in worldwide VLBI ? • VLBA strengths: • Dedicated array/uniform data/always available • Parallax scheduling, transients… • Good high frequency performance • Near-realtime multi-frequency observations • Good (u,v) coverage/imaging/high resolution • Very flexible correlator, eg, optimum pulsar gating; multi-position correlation • EVN strengths: • Large number of antennas • Large collecting area • Good low-frequency performance • eVLBI realtime operation • VERA strengths: • Dedicated for astrometry: already 25 parallaxes • Simultaneous dual-beam observations Other VLBI Networks

  13. What role does the VLBA play in worldwide VLBI ? • HSA strengths: • Highest sensitivity (sS ~ 1 mJy) • Phased-EVLA soon • Japan/Korean (East Asian) VLBI • 13 Japanese, 3 (new) Korean, 4 Chinese ants • Australian LBA; proud of international users! • 12-m in New Zealand; • ASKAP (36 12-m) will join at L-band • Global Arrays: • MeerKAT will be a 100-m class VLBI station, plus • other African telescopes may join VLBI efforts • 3 mm-VLBI (14 antennas) studies most variable AGN emission • China’s 4 antennas joining arrays; • soon Shanghai 65-m and then FAST • Event Horizon Telescope (EHT): • Image dynamic region @ “event horizon” resolution Other VLBI Networks

  14. How can we reduce the budget deficit? Can we increase competiveness? • Increase revenues • Decrease expenses • Upgrade (or die) • Add capability (eg, 4,32,160 Gbps; C-band rcvr; wide-field correlation/surveys) • On path to SKA-high: “NAA” State of the “VLBI Union”

  15. How can we raise revenue and/or cut costs? • Fermi contribution (why not spend 10% of 8M$/yr grant program as partial support for VLBA observations) • “Sell” more geodetic/geophysical time • Spacecraft tracking • NRAO “bake sale” • “Mission projects”: decrease user support; • users help with data quality assurance • Dropping antennas absolute last resort • Array designed for optimum (u,v)-coverage over all Declinations: minimum # of antennas = 10 • 20 – 40% degradation for 8 vs 10 antennas • No obvious antenna(s) to drop: SC poor @ high-freq, but important for NS beam @ low freq • Even for astrometry only, some sources done with “inner-5” when maser spots are large What to do?

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