ARISEVSOP2 Jim Ulvestad

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ARISEVSOP2 Jim Ulvestad

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Title: ARISEVSOP2 Jim Ulvestad

1
ARISE/VSOP-2Jim Ulvestad

ARISE Mission Science Drivers
Changes in Science and Mission
VSOP-2 Status
VSOP-2 Partnerships and Outlook

2
ARISE Mission

Space Very Long Baseline Interferometry mission
Proposed 25m antenna, operating at frequencies up
to 86 GHz, in elliptical orbit with apogee height
of 40,000 km
Resolution better than 20 microarcseconds
AANM cost estimate of 350 million
Biggest technical challenge was to make the 25m
aperture accurate enough to operate at 86 GHz
Deployable or inflatable antenna?
Planning assumed only 8 aperture efficiency at
86 GHz

3
ARISE Science Drivers

AANM
Supermassive black holes and relativistic jets
Maser sources in Milky Way and other galaxies
Q2C
What is the nature of dark energy?
How do cosmic accelerators work and what are they
accelerating?

4
Science Changes

Massive black holes now more closely linked to
galaxy evolution
Magnetic fields increasingly viewed as being
critical in acceleration and collimation of
relativistic cosmic jets
WMAP cosmology has greatly refined cosmological
parameters, but finding more accurate value of H0
is critical for removing degeneracies in
determination of w, Om

5
WMAP Constraints on Om, O?

WMAP alone constrains relation between Om and O?,
but does not strongly constrain their absolute
values
Knowledge of H0 to better than 5 is critical

Spergel et al. 2006
6
Constraining w by Constraining H0
Spergel et al. 2006
7
AGN Unification (Antonucci ARAA 1993)

Broad-line AGN (Type 1) if seen down the jet
axis
Narrow-Line AGN (Type 2) if seen from the side
Many new SDSS Type II AGNs

Peck, Taylor, Conway 1999

8
NGC 4258

H2O megamaser emission associated with nuclear
torus
Direct measurement of BH mass of 39 million MSun
Geometric distance of 7.4 Mpc
Can we find distances further out in the Hubble
flow, and determine the Hubble Constant to better
than 3 accuracy?

9
Spectra of H2O Maser Disks to 100 Mpc
Braatz et al., in preparation (using GBT)
10
M87 Inner Jet
M87 Base of Jet 43 GHz Global VLBI Junor,
Biretta, Livio Nature, 401, 891
VLA Images
Resolution 0.?00033?0.?00012
Black Hole / Jet Model
VLBI Image
11
Where Most X-rays ?-rays Are Emitted
clouds
X-rays ?-rays
Invisible?
Radio core
12
Mission Changes

ARISE was behind Constellation-X and LISA in NASA
roadmaps
No significant chance of flying ARISE in the next
10-15 years
JAXA has approved VSOP-2 as a full-scale
scientific mission, with planned launch in
February 2012
3.5 times the ground resolution for 22 GHz H2O
masers
At least 13 radio AGNs with resolution better
than 200 Schwarzschild radii

13
Observing Parameters
14
VSOP-2 Status

VSOP-2 approved as science mission by JAXA
Strong budget limit of 100 million, not
counting launch vehicle and some ISAS salaries
Excellent development/planning process for the
deployable antenna
Heritage from ETS-VIII, to be tested later this
year
Growing East Asian VLBI community

15
Mesh Antenna Segment in Development
16
ETS-VIII Deployment Test

ETS-VIII scheduled for launch in next six months
?/50 at 2.3 GHz
Deployment mechanism the same as VSOP-2 antenna
VSOP-2 will have additional on-orbit adjustment
mechanisms

17
VSOP-2 Partnerships/Outlook

Space VLBI inherently requires international
partnerships, and needs 3 primary U.S.
contributions
Worldwide tracking stations needed to bring down
1 Gbps science data in real time
Few-cm orbit determination needed for water maser
science and high-frequency observing
(GPSaccelerometer)
Worldwide ground radio telescopes needed to
provide significant imaging capability
U.S. telescopes are dominant for the
high-frequency science (22 and 43 GHz)
U.S. telescopes will provide most ground
baselines of at least a few thousand km

18
VSOP-2 observation
2 Gbps/Max
PC DISK
FEDEX
1 Gbps
Correlator
IP/Network
Total Data Size 2 Gbps x observing time x
Number of Antenna
IP/Network
Typical Observation Observing time 12
hours Number of antennas 11
121.6 T byte / 1 observation (12 h)
19
VSOP-2 Science Outlook

VSOP-2 is a huge observational step toward the
capabilities envisioned for ARISE, and has the
potential to deliver significant results on its
primary science goals
Determine H0 to 3-5 (depending on systematic
errors), to break degeneracy in cosmology models
Image changes in the flaring blazars seen by
GLAST
Image jet collimation within 200 Schwarzschild
radii of a number of nearby black holes
U.S. contribution to VSOP-2 will greatly improve
the fundamental science of the mission, provide
scientific access to the U.S. community, and
fulfill the AANM recommendation, for a small
fraction of the ARISE cost