Russian Space-VLBI missions: results and prospects

Sergey Likhachev (On behalf of Astro Space Center, Lebedev Physical Institute Russian Academy of

Sciences), and Alexangr Alferov (Scientific Secretary of RAS Space Council)

*Horsehead image captured by Herschel telescope

Radioastron Mission

The aim of the mission is to use the space telescope to investigate the Universe with the extraordinary high angular resolution up to 8 micro arc seconds at the shortest wavelength 1.35 cm.

“Radioastron” is the largest space radio telescope in the world, forming the largest ever space-ground interferometer.

Tests in Lavockin Assotiation, Summer, 2011

July 18, 2011

6:31 Moscow time, Baykanoor.

Launch of the observatory.

Radioastron Orbit

Antenna diameter [m] 10

Apogee height [km] 350,000

Orbital period 9.5 days

Polarization LC/RC

Data downlink 128 Mbit/s

Observing frequencies [Ghz]

0.2 -- 22

Highest resolution [microarcsec]

8

Puschino, Russia 22 m Green Bank, USA

43 m

Ground tracking stations

Urumqi China Tidbinbilla Australia Shanghai China Parks Australia

Onsala Sweden

Noto Italy

Jodrell Bank UK

ATCA Australia

Hart Africa Robledo Spain Torun Poland

Scientific Data Transferring from Ground Telescopes

Effelsberg Germany

Arecibo Puerto Rico

GBT USA Medicina Italy Westerbork Netherlands Yebes Spain

Badary Russia

Zelenchuk Russia

Svetloe Russia Usuda Japan

Structure of Data Processing Center

Computer clusterSw

itch

10 G

b

Server

On-linestorage for collection

and checking information 600TB

Tape library

node 1

node 2

node 3

node 4

node 5

node 6

node 7

node 8

node 9

node 10

Archive on HDD 2000 TB

Computer of operator

Storage for data processing 80 TB

Archive on tape2000 TB

Storage for results of processing 120 TB

Server for checking information

Main Pulsar Results in Radioastron Mission With "Radioastron" was obtained the spatial distribution of the interstellar medium inhomogeneities in the direction of the pulsars: B1919 + 21, B0950 + 08, B0329 + 54, B0531 + 21. For the first time with ultra-high resolution, was discovered a sub-structure in scattering disk of these pulsars. Published статья Astrophysical Journal, 2014

Scattering disk for PSR 0329+54 was resolved by direct observations at long baselines with angular diameter of 5 mas Published Astrophysical Journal, 2016

Giant pulses from Crab pulsar First time Space-VLBI observations of giant pulses from B0531+21 pulsar. Observed significant change in CCF shape for space-ground baselines. At 92 cm scattering disk is being resolved on ground-ground baselines. Rudnitskiy A.G., Popov M.V., Soglasnov V.A., “Preliminary results of giant pulse investigations from Crab pulsar with Radioastron.”, Proceedings of Science, EVN 2014 (065) Rudnitskiy A.G., Popov M.V., Soglasnov V.A., Karuppusamy R., Astronomy Reports, 2016, 93

Radioastron mission main results. Pulsar 1641-45

An image of pulsar B1641-46 scattered by interstellar medium.

• For the first time in the history of radio astronomy space-ground interferometer detected water in

extragalactic mega maser (18.12.2014.). • Baseline projection Radioastron – Green Bank (USA) - 2 Earth diameters. • Galaxy NGC4258, z = 0.00149, distance 24 millions of light years.

Mega maser is located in the accretion disk gas around the black hole.

Radioastron mission main results. NGC4258 galaxy

Radioastron Angular Super-Resolution

Baseline projections:

L-band: 27.1xED, (345 000 km), Source: 0048-097

С-band: 23.1xED, (295 000 km), Source: 0716+714

K-band: 15.5xED, (190 000 km), Source: 0851+202

Comparison with Ground VLBI (3C84, 5 GHz)

with “Radioastron” without “Radioastron” 13

Current Radioastron Correlation Results

• Data from 2130 sessions have been successfully correlated. Fringes on Space-Ground baselines were found in 703 observations.

• For now, data processing rate in "Radioastron" mission is about 160 sessions per month, observation rate is 80-120 experiments per month. Thus, ASC correlator performance is enough to correlate all the data in "Radioastron" project.

The first 10-m space telescope

for the FIR, submm and mm range (diffraction limited 80µm) for cosmology and astrophysics deployable and adjustable on orbit mechanically cooled (<10K) with post-cryo life orbit around L2 Lagrange point lifetime: 10 years; at cryo >3 years dual operation modes:

• S-VLBI for 0.3 – 17 mm • Single dish for 0.02 – 3 mm

Mission has been approved and supported by RSA Spacecraft in Phase-B Science payload in Phase-A Launch date : 2025

Millimetron Mission

SWAS 1998

IRAS ISO 1995

Spitzer AKARI 2006

Herschel

WISE

SPICA 2025

All Sky Survey

JWST 2018

1983 2014

2003

2009 SOFIA

2011

The satellites addressed to measure CMB

COBE

WMAP Planck

1989 2001 2009

Odin

2001

2009

Sky

Surve

y

Spectrum Survey

Mmtron 2025 +

SPICA 2025

Evolution of the FIR/Submm/Mm Instruments for Space Science

Millimetron Orbit

• Orbit period – 365 days (L2). • Baseline – 1 500 000 km, max. • Time of oscillation around L2 is

about half of a year. • MM antenna view angle opening

is+/- 75 deg in ecliptic latitude and longitude.

1.0E-04 4.8E-05

1.4Е-6

1.0E-07

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

1.0E-02

1.0E-01

1.0E+00A

ng

ula

r R

esol

uti

on (

arcs

ec)

VSOP VSOP2

Radioastron Millimetron

Millimetron

unprecedented high angular resolution in observing mode as S-VLBI element

Mmtron

ALMA

0235+164

Capabilities of the Millimetron

ALMA

EHT

Antenna Mock-Up (ISS-Reshetnev, Russia, 2014)

19

20

Conclusions

• The Russian Federation has the technology create unfolding space antennas of large diameter ("Radioastron" and "Millimetron“ missions).

• The Russian Federation has the technology of space-ground interferometer scientific data processing and analysis.

• Mission "Radioastron" yielded scientific results that are unique in modern radio astronomy.

Thank you for your attention!