HITRAN Conference 2006

Stephen S. MurrayDeputy Director for Science

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Center for Astrophysics Brief History

HCO formed in 1839, and SAO in 1890

SAO moved to Cambridge from Washington DC in 1955

Harvard-Smithsonian CfA formed July 1973:"To put in conjunction with words Harvard and Smithsonian--as they were officially conjoined in 1973--is to designate not a place nor an assemblage of equipment, but rather a kind of astronomical personality. The two names belong together, certainly. To the extent that they have been connected with astronomy, they have meant flexibility, enterprise, international connections, an appreciation for the public interest in astronomy, a certain amount of crankiness, an indulgence toward amateurs, initiative in undertaking projects of doubtful outcome, appreciation of the personal history of scientists and the peculiar histories of scientific institutions, sophisticated naivete, hospitality toward women scientists, and genius for organization. In reading book-length histories of both institutions and in studying their current undertakings, one becomes aware that they display simultaneously the virtues of youth and old age, without the vices of either."

–...from U.S. Observatories: A Directory and Travel Guide, by H.T. Kirby-Smith

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Structure of CfA• Total Staff ~ 1000

• Science Divisions ~300 Scientists• Atomic and Molecular Physics

• Solar, Stellar and Planetary Sciences

• Theoretical Astrophysics

• High Energy Astrophysics,

• Optical and Infrared Astronomy

• Radio and Geoastronomy

• Centers

• ITAMP, CXC, TDC, MPC, CXT,

•Administrative Departments–Travel

–Human Resources

–Contracts and Grants

–Subcontracts and Procurment

–Financial Management

–Science Education (and SMG)

–Public Affairs

•Technical Services–Computation Facility

–Central Engineering

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CfA Geography

• Main Campus - 60 Garden St• Science Divisions (except RG)

• Original HCO and SAO

• Great Refractor Telescope - Shapley

• Concord Ave• RG, SMA, Receiver Lab

• Draper Labs Hampshire St• Chandra OCC

• Cambridge Discovery Park• Admin Departments, CE, CF, SMG, ...

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CfA Major Facilities

Chandra X-ray Observatory

Spitzer Space Telescope

GMT

Ground Space Future

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• Cosmic Census: Matter, Dark Matter and Dark Energy• Normal Matter - 4-5%

• Dark Matter - New Sub-atomic particles- ~25%

• Dark Energy - New Force, new physics - ~70%

Science Example

Dark Matter ~25%

~70%

Normal Matter ~4%

Visible Matter ~0.4%

Dark Matter• “Missing Mass” Zwicky 1930’s

•Clusters of Galaxies:•Galaxies move too fast (~1000 km/s or ~2 million mph)•There is not enough visiblevisible matter•Need 10-20 times more mass• Discover more mass - X-rays (1970’s)• Hot gas (100 million degrees)• Fills the cluster, but still not enough matter• 5-10 times is still “Missing”“Missing”

Coma Cluster

• X-ray gas confirmsconfirms dark matter

•Something whose gravity holds hot gas in place•There must be 5-6 times more dark matter present than what we sense

X-Ray (CXO)

•Galaxies also have dark matter halos Rubin 1960’s

• Zwicky was right!Zwicky was right!

Dark Matter and Gravity•Einstein’s General Relativity predicts that dark matter should produce gravitational lenses

• Results agree with X-ray mass

CL 0024+1654 (HST)

•What is Dark Matter?•New type of matter that exerts gravity, but does not radiate => exotic!exotic!•What’s Next?•Image more lenses in more detail to find structure in dark matter--smooth or clumpy?•Study internal motions of galaxies to map the dark matter they contain•Measure the interactions of dark matter with normal matter, if any

Lens Simulation

• We must be doing something right!

•Supernova allow us to see into the distant, and early Universe

•We have now measured the expansion rate out to distances of more than 6 billion light years.

•Hubble plot from a decade ago, made from observations out to about a billion light years.

Expansion of the Universe is Expansion of the Universe is accelerating!!!accelerating!!!

=> Dark Energy (“anti-gravity”)

Expanding Universe Edwin Hubble

•The Milky Way was not the whole Universe--we live in a Universe of galaxies.

•The Universe is expanding at a constant rate (the Hubble Constant)

BrighterCloser

Deceleration

FainterMore DistantAcceleration

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Surprise!

Finding Supernovae

• 1 Supernova (SN la) per century per galaxy• ~1/sec Universe

What’s Next?What’s Next?

•Find more supernova, especially distant ones, redshift effect means look in near IR

•What is Dark Energy?

•What is the new physics?

•Repulsive force--Anti-gravity?

Hubble Space Telescope

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Possible Reconnect to HITRAN?

• Future Optical Observatories• High precision multicolor photometry

• Derive redshift estimates • Intrinsic source luminosities

• Atmospheric corrections needed• Includes transmission and scattering• Models can be tested with spectrographic redshifts