ALMA Extended Arraydiono/meetings/EA_Development... · Essential point of the ALMA extended array...

ALMA Extended Array!

Seiji Kameno (Joint ALMA Observatory） Naomasa Nakai (Tsukuba U.) Yoichi Takeda, Kiyoto Shibasaki, Mareki Honma, Tomoya Hirota (NAOJ) Yoichi Tamura (IoA Tokyo U.)

Thermal Universe with a VLBI resolution!

7 stations in 300-km range

ALMA-AOS!ALMA-OSF!

Calama!

Zaldívar!

Llullaillaco!

Llama-Macon!

Llama-SAC!

ALMA Extended Array : EA ALMA Development Workshop 2013 July 9! /18!2!

ALMA extended array, compared w/ ALMA and VLBI ALMA VLBI

•  Dense array (10m - 15 km) •  Tb sensitivity ~10 K •  Resolution ~ 10 - 100 mas

•  Long baseline (~1000 km) •  Tb sensitivity ~108 K •  Resolution ~ 0.1 - 1 mas

Targetting dark/cold unverse Extreme resolution for non-thermal sources

ALMA extened array VLBI resolution for !Thermal emission!

Precise images than ALMA New parameter space (e.g. stellar images)


Essential point of the ALMA extended array • Stations : ~ 5 + 2 (from Llama)!• Sensitivity : σ=2 μJy@3600 sec!(20 μJy without ALMA)!• Resolution： 0.6 mas!• Tb detection limit： 5σ = 1000 K!(3000 K without ALMA)!

Thermal universe w/ VLBI resolution

300-km baseline is the upper limit for detecting thermal emission

Baseline-to-aperture ratio = aperture filling factor

7 stations in 300-km range

ALMA-AOS!

Array config.! Thermal Universe with a VLBI resolution!

Sites! Altitude! Latitude! Longitude! Dist. from ALMA!

AOS! 5000! -23.030! -67.755! 0!

OSF! 2900! -23.073! -67.980! 24 km!

Calama! 3400! -22.706! -68.428! 78 km!

Zaldívar! 3300! -24.232! -68.893! 177 km !

Llullaillaco! 4000! -25.227! -69.040! 277 km!

Llama-SAC! 4755! -24.228! -66.455! 188 km!

Llama-Macon! 4600! -24.675! -67.305! 188 km!

•  Alt.> 3000 m for 350 GHz •  Access roads •  Baseline length：24 - 300 km •  (u, v) coverage : E-W and N-S direction •  Llama project, preparing 2 stations in Argentine

ALMA-OSF!

Calama!

Zaldívar!

Llullaillaco!

Llama-Macon!

Llama-SAC!

300-km baseline is the upper limit for detecting thermal emission


AOS - OSF 24-km interferometry

Science Case 1!!Super massive black holes :! formation and fueling!



Science highlights : Black Holes

Sub-mm galaxies discovered with ASTE (Tamura+09 Nature, 459, 61)

Supermassive Black Holes (SMBHs) in galaxies

•  Sub-mm galaxies in the early Universe!•  Search for SMBHs in high-z galaxies •  Clarify Galaxy / SMBH co-evolution •  High resolution to discriminate AGN from SB

•  BH engines in nearby AGNs!•  Mass accretion process from galactic disk to BH •  Census for RIAF at sub-mm SED peak •  Imaging BH+accretion disk（as a part of sub-mm VLBI）

Evolving BH in a galaxy (artist’s impression)

SED of SgrA* RIAF disk (Yuan+03 ApJ, 598, 301)

ALMA Extended Array : EA ALMA Development Workshop 2013 July 9! /18!

Mass accretion processes from galactic disk onto SMBH

福江純「輝くブラックホール降着円盤」p.162

What is the source: Stars, Gas, or Dust?!

How does matter lose angular momentum?!

Spatial resolution imaged by AeA!

Galactic rotation ↓ BH-bound rotation

in 1-10 pc

Cen A w/ SMA : Espada+09, ApJ, 695, 116


Imaging dust torus (土居2012:AEA workshop)


Approaching the central engine of AGNs

Black-hole positioning by multifrequency core-position offset (Hada+11, Nature, 477, 185)

Radio ‘photosphere’ of the jet …frequency dependent

Hi-Fi imaging at > 40 GHz!•  High frequency to see through jets •  High dynamic range to discriminate the disk from jets •  Middle baseline (~ a few 100 km) to fill (u, v) hole in sub-mm VLBI

Simulation images : Nagakura & Takahashi (2010)

Science Case 2!!Stellar imaging and size measurements!



Science highlights : Stars

Stellar physics!

Imaging photospheres of nearby giants / supergiants!•  100 x 100 pixel images for Betelgeuse and Antares •  Flares, Prominences, CME •  Convection cells / Dynamo •  Motion of active regions •  Long-term monitor for magnetic inversion

Betelgeuse NIR image (10-mas resolution) (Kervella+09, A&A, 504, 115)

The sun imaged with the Nobeyama Radio Heliograph (180 x 180 pixel) Betelgeuse H-band image (9-mas resolution)

(Haubois+09, A&A, 508, 923) comparable w/ the sun!

NIR visibilities


ALMA stellar imaging Size measurements (photosphere imaging) of nearby Giants!

•  Stellar apparent diameter

•  Flux density

e.g. 3000 K, 300 R8@ 1 kpc → 7 mJy → 7σ detection requires 30-min integ. w/ ALMA!

Antares (700 R8, 175 pc) → 40 mas!

Stellar Radio Astronomy

← 6μJy!3σ@3600 sec!

← 60μJy !without ALMA!3σ@3600 sec!

to bring • stellar imaging capability • size measurements • distance estimation


Stellar size measurements

Size measurement of aM dwarf star

← 6μJy!3σ@3600 sec!

M dwarf @ 10 pc can be measured to determine its mass

Imaging giants@1 kpc Size measuring giants@10 kpc, main sequence@70pc

Distance determination without annual parallax

if we can estimate the linear size

- toward Galactic Center!- more than 20,000 sources!


Science goals of stellar size / imaging

•  Science goals : phase 1!•  500 supergiants to be imaged (δ < 20º, K < 6 mag, lumi. class I and II) •  1-hour / source → 500 hours •  Verify previously measured size and distance •  Establish size-spectral type-luminosity relation •  Surface activity (flares, spots, convection cells) •  Binary systems

•  Science goals : phase 2!•  20000 giants (δ < 20º, lumi. class III) •  4 sources / hour → 5000 hours •  Angular diameter → distance •  Precise galactic structure and dynamics beyond the center (NA w/ GAIA) •  Whole lifecycle of stars •  BH mass accretion by stellar dynamics

500 supergiants for phase 1!


AEA workshop on Nov. 2012

Early Universe / AGN

Requirements for better Tb (~ 100 K) sensitivity

→ shorter baseline (up to 100 km)

Steller imaging Requirements for better resolution : θ ~ 0.3 mas

• Longer baseline (~600 km) • Shorter wavelengths (~650 GHz) • Increase # of stations?

Feedbacks from science requirements are welcome!

• thermal emission from dust torus • counter / diffuse jets

• main sequence stars • convection cells • transit of planets

http://milkyway.sci.kagoshima-u.ac.jp/groups/workshopalmaextendedarray2012/

ALMA Extended Array : EA ALMA Development Workshop 2013 July 9! /18!

Summary : AEA = ALMA sensitivity + VLBI resolution Requirements

Schedule!

Cost!FY X X+1 X+2 X+3 X+4 X+5 X+6…

survey!

const-ruction!

oper.!

Site survey!

Technical development!

Infrastructure!

Antenna!

RX / Backends!

Tests!

Full Op.

• 12 m (ALMA design) x 5 antennas!• BW 16 GHz (4 GHz x 2SB x Dual pol.)!• Baseline 300 km!

Bands! 350 GHz (230 GHz, 650 GHz)

Resolution! 0.6 mas

Image sensitivity! 7σ = 10 μJy (1 hr)

Tb sensitivity! 7σ = 1000 K (1 hr)

Site candidates (need survey)

Specifications

total ~ $100M!

Stations ￥1970 M/ant×5 = ￥9850 M site 150 M, ant 1400 M, FE 300 M, BE 120 M

Computing ￥200 M

Tests ￥600 M

Managements ￥200 M


Technical Issues

•  Site survey !‣ Higher altitude / sufficient (u, v) coverage!•  Sub-mm coherence at long baselines!‣ LO distribution / individual frequency standards?!‣ Phase compensation : switching / VERA-like dual beam?!•  Fiber connection!‣  > 100 km optical fibre / VLBI recording?!•  Correlator!‣ Number of baselines, faster phase tracking, larger delay buffer!•  Calibration plan!‣ Are there good calibrators?!•  Operation planning!‣ Impacts on ALMA!•  Multi-Frequency Synthesis!

ALMA Extended Arraydiono/meetings/EA_Development... · Essential point of the ALMA extended array...

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