February 2004

Five (or so) Easy Problems

Douglas RichstoneUniversity of Michigan

February 2004

What is the most interesting attribute of a 30 meter space

telescope? ResolutionSpectral regimePhoton rate

February 2004

1. Long ago and far away…

4 mas is ~20 nano radians

February 2004

Physical resolution vs distance (0.1arcsec vs 4mas)

February 2004

Because the angular size distance never exceeds 1.6 GPC, the resolution of a 30 meter space telescope is better than 30 parsecs anywhere in the universe.

0.1 arcsec

February 2004

Hdf

February 2004

The HDF was observed at a resolution of about .05 arcsec (about 200 parsecs)…

The patch at left at 20 parsecs might look like the following pictures.

February 2004

Hcg87

February 2004

Hcg87big

February 2004

N1410

February 2004

“Go Deep”1

Any object in the HDF (or anywhere) can be studied with the physical resolution of current studies, of eg, the HCG 87 (or better)2 subject only to surface brightness issues.

1 Former Oakland quarterback Ken Stabler in reply to a question from President Reagan about whether to build the SSC.

2 HCG 87 is at 100 Mpc.

February 2004

2. What about those pesky black holes?

February 2004

Likely BH mass and detection length-scale

Based on the Mbh~4 law and the radius of influence ri = GM/ 2,

We show ri for various bh masses.

Sigma Bhmass R_influence

10 km/s2050100200350

843 Msun135005.3E58.4E61.35E81.3E9

0.035 pc0.14 0.883.514.143.1

February 2004

Nearby resolution

February 2004

Bhdetect distance versus M

February 2004

Black Holes

See 10^9 Msun BH anywhere- can study the evolution of the BH fundamental plane and ‘Madau Plot’ for the biggest objects in the universe.

See 1000 Msun BH anywhere in local group

Investigate cDs with stellar dynamics See intermediate mass objects in Virgo

cl.

February 2004

3. What does M31 look like?

February 2004

M31 at hst resolution.

February 2004

Resolution criterion

Y = I 2 /f*, Y~1 is resolved, y>>1 isn’t. I <~ m* + 5 log. I is mags/arcsec2

at M31, I = 24 -12.5 = 11.5 at Virgo, I = 30 -12.5 = 17.5

February 2004

M31 GST

February 2004

M31gst big

February 2004

Those central populations

In M32, and in many globular clusters, the physical collision time is not much longer than a Hubble time (in some cases much less)… find and characterize the collision products.

February 2004

4. What does our galaxy look like?

February 2004

4. The galaxy is kinematic

4 mas is 20 nanoradians This is 40au at 10kpc. - astrometry 100 km/sec ~10-4pc/yr, at 10kpc this is 10nr/yr. Can

paint the halo with proper motions vectors. Dv/dt =v2/r ~v/10^8 yr - galaxy is kinematic, not

dynamic (except very close to the center). Back to those globular clusters… get pms there and

have 5/6 of phase space.

February 2004

Its difficult to make predictions

about the future