Millimeter VLBI with ALMAand Its User Support
ALMA/45m/ASTE Users Meeting 20162016/Dec/19-20, Mitaka

Kazuhiro Hada
Mizusawa VLBI Observatory, NAOJ
(A member of the Event Horizon Telescope Consortium)

Millimeter VLBI with ALMA
• Utilize the ALMA as a single large (~84m) dishby phasing up the individual ALMA antennas• Incorporate the phased ALMA into existing
global VLBI networks at mm wavelengths• Dramatic boosts in sensitivity (x10), uvcoverage, and N-S angular resolution (x2) of themmVLBI networks• Ultra-high-resolution (a few 10s µas) studies ofAGN/SMBHs/compact radio sources• Opened in Cycle-4, offered in Band-3 andBand-6. (also Band-7 planned in future)

ALMA Phasing Ready for VLBI.
The ALMA Phasing Project (APP)
ALMA Phasing System observation from August 2015:"

Example of ALMA phasing in Aug/2015 (Band 3)•IRAM-ALMA 1.3mm- Band 3 "- 25 phased antennas"- Baselines <1.4 km"- dual polarization (XX, YY)"
- 4 ✕ 1.875 GHz bands"- Phasing efficiency ~90%"2π"

Led by MIT-Haystack, promoted incollaboration with NRAO, MPIfR,
ASIAA, NAOJ, CfA etc• APP-CSV campaign started in Jan/2015. Five CSV campaigns to date
• Confirmed several successfulintercontinental fringes at 3mm/1mm• Ready for Cycle-4 use

mean ϕrms ~ 9 degrees"

5 minutes"

Several Successful Campaigns
1.3mm VLBI Fringes to multiple site

3mm and 1.3mm VLBI offered to thcommunity in Cycle 4.
Talk by Lynn Matthews.

NRAO/AUI/NSF

Millimeter VLBI networks in Cycle 4

SMT

3mm (Band-3): Global Millimeter VLBI Array (GMVA): ~70µas
1mm (Band-6): Event Horizon Telescope (EHT): ~30µasVLBI with ALMA in Cycle 4:Proposal constraints•••

Band-3 & Band-6
Non-standard mode
Up to 5% of ALMA Cy4 time, shared between Band-3 and Band-6– Only Grade-A proposals accepted•

Up to 37 phased 12m antennas– Equivalent to a single 73m diameter antenna with SEFD~100Jy•

Targets should have correlated flux densities of:– >500mJy on intra-ALMA (1km) baselines– >50mJy on intercontinental (~5000km) baselines••••

Declination range -45°<Dec<45° recommended
Recording rate: 2Gbps (Band-3), 32Gbps (Band-6)
Full-Stokes OK (XY to LR through the “PolConvert” software)
In addition to submitting a usual ALMA proposal, VLBI programs mustalso submit the same proposal to the GMVA (Band-3) or the EHTConsortium (Band-6)

Cycle 4 outcome•••Submitted: 10 (Band-6), 12 (Band-3)– From non-EHT community: 1
Accepted: 6 (Band-6), 3 (Band-3)– From non-EHT community: 0
Band 3 (3 accepted):

ALMA Cy4 SelecIon StaIsIcs– “Imaging the Global Magnetic-field Structure Near SgrA*: 3-mm VLBI with GMVA+ALMA”– “Probing the active collimation region of the relativistic jet in 3C 273”
– “Understanding jet formation and testing the binary SMBH system in OJ287”•Band 6 (6 accepted):– “Imaging the Shadow of a Supermassive Black Hole: Event Horizon Telescope
Observations of SgrA*”– “Imaging the Black Hole Shadow and Jet Launching Region of M87”
– “Zooming into the heart of the closest radio galaxy:1mm VLBI observations of Centaurus A”– “Imaging the candidate binary SMBH in OJ287”– “Looking into the throat of the magnetized gamma-ray blazar 3C279”– “Pinpointing the Highly Magnetized Twin-Jet Base Near a Supermassive Black Hole”

“Imaging the Shadow of a Supermassive Black Hole:
Event Horizon Telescope Observations of SgrA*”
PI: The EHT Consortium• The nearest SMBH (1Rs = 10µas)• Physics of BH accretion, test GR M87• B-field structure in accretion flow

aging theBlack Holeand Shadow
Jet Launching
Region“Imagingthe Shadow
BlackHoleandof M87

Jet Launching
PI: The EHTRegion
consortium of M87”
PI: The EHT Consortium

VLBA image at 7 mmJet
Counter-Jet
BH

B-fieldJet
PdBI

Central region of M 87(GRMHD simulation)

SMT
JCMT/SMACounter-JetPVLMTALMA/APEX

100 RsModelwithout ALMA

EHT array 2017with ALMA

5.2 Rs• The nearest SMBH with powerful relativistic jets
1. ProjectOverview.
(top)
Image of M87 at 7 mm with the VLBA. Upper Insets show particle dens
• Physicsof BH
outflows
agnetic field lines threading a simulated jet (Moscibrodzka+ 2016) and the 2017 EHT array as viewed fr• ModelB-fieldstructure
in 230jet launchingregionEHT reconstructions. The model image is ba(bottom)
imageof M87 atGHz with simulated

ALMA-VLBI user support• So far, the calibration/analysis procedure of ALMAVLBI data has not been fully established yet– Fringe fitting, phased-ALMA properties, amplitude,polarization, imaging etc.
– Software: AIPS, CASA, HOPS ?
– Data delivery to users (when, how)
– Data archival policy• The EHT Consortium (incl. Miz-VLBI Observatory)
will learn and establish standard data processing
pathways using the Cycle-4 data
– Band 6: April/4-15/2017– Band 3: prior to April/4/2017• User-friendly documentation, manual

Towards Cycle-5• The proposal submission procedure will besimilar to Cy4 (probably): requires two steps– Band-3: Feb/1/2017 to GMVA & Apr/2017 to ALMA– Band-6: Apr/2017 to ALMA and also to EHTC

• The ALMA-VLBI mode is open to the wholeastronomy community– not just for the EHT community!

• If you are interested in (but not familiar withVLBI), please feel free to contact us. We are
happy to support you.