Board on Physics and Astronomy

Christopher McKee's Remarks at the Public Release of the Astronomy and Astrophysics Survey

As Joe [Taylor] mentioned, we live in an exciting time, in which fundamental questions about the universe around us are being answered. Just in the last decade, astronomers found planets around other stars, galaxies in the process of formation, and evidence for what may be the dominant constituent of the universe, "dark energy.'' Many mysteries yet remain, and the Astronomy and Astrophysics Survey Committee has attempted to chart a path for extending our knowledge by setting priorities for new initiatives for the coming decade. These initiatives are comprehensive, covering the electromagnetic spectrum and, for the first time, part of the gravitational wave spectrum. They will address a number of fundamental questions that are ripe for progress:

What is the structure of the universe---what is it made of? How old is it? What is its fate?
What occurred at the dawn of the modern universe, when the first stars and galaxies formed? At present, we know almost nothing about this era.
How do black holes form and evolve, both those with the mass of a star and the huge ones in the centers of galaxies?
How do stars and their planetary systems form? How do individual planets, ranging from Earth-like to Jupiter-like, form and evolve?
What causes the astronomical environment---particularly the Sun and asteroids---to affect the Earth?

The highest priority for a major new initiative in the coming decade is the Next Generation Space Telescope (NGST), a worthy successor to the Hubble Space Telescope. NGST will have an 8 meter aperture, whereas Hubble has 2.4 meters; NGST will focus on the infrared region of the spectrum, whereas Hubble focuses on the optical and ultraviolet regions. The primary goal of NGST is to study the first stars and galaxies at the dawn of the modern universe. It will look farther back in time than any instrument except those devoted to the study of the cosmic microwave background. Its sensitivity and infrared capability will enable us to dramatically advance our understanding of the formation of stars and planets in our own Galaxy as well. Both the European Space Agency and the Canadian Space Agency plan to make significant contributions to this instrument.

The second priority, and the top priority for ground-based astronomy, is the Giant Segmented Mirror Telescope (GSMT), a 30 meter telescope with adaptive optics. GSMT will have the same relation to NGST that the Keck telescopes have to Hubble: its greater light-gathering power will enable it to obtain higher resolution spectra than Hubble, so that it can study the physics of distant objects with a sensitivity never before achieved. It will be a powerful instrument for studying the evolution of galaxies and the intergalactic medium. The committee recommends that technology development begin immediately so that construction can be well underway by the end of the decade. We have assumed that half of the capital cost will be borne by private or international partners.

Next, the committee recommends the Constellation X-ray Observatory, which consists of four satellites working together to probe the formation and evolution of black holes by studying the X-rays emitted as matter falls into them. Far more powerful than the recently launched Chandra X-ray Observatory, it will trace the history of the formation of the elements. It will also enable us to use the universe as a laboratory to study matter under extreme conditions on neutron stars and near black holes.

The Expanded Very Large Array (EVLA) will rejuvenate the VLA in New Mexico, which is currently the premier telescope in the world for studying the universe at centimeter wavelengths. By upgrading the VLA's technology, some of which dates back to the 1970's, and adding some dishes, the EVLA will be able to study newly forming galaxies and stars just as NGST will, but from a completely different perspective.

The Large-aperture Synoptic Survey Telescope (LSST) will open a new window on the universe, the time domain. A 6.5 meter-class, ground-based, optical telescope, it will survey the sky each week down to 24th magntitude. Over a decade, it will discover 90% of the near Earth objects larger than 300 meters and assess their threat to Earth. It will enable the discovery of thousands of supernovae. By adding the images of the sky together from week to week, it will be possible to build an image of the sky to yet fainter levels, enabling the mapping of the distribution of dark matter. The data from the LSST will be available on the internet to professional astronomers and the public alike.

The Terrestrial Planet Finder (TPF) is designed to find Earth-sized planets around nearby stars and to search for evidence of life. This is by far the most technologically challenging science mission yet attempted by NASA. The current design is for a suite of four 3.5 meter space telescopes working together as an interferometer. Operating at infrared wavelengths, which penetrate the dust in galaxies and star-forming regions, it will be able to resolve details more than 10 times finer than Hubble, and thus will be a powerful instrument for studying quasars and star-forming regions as well.

The final recommendation for a major initiative is the Single Aperture Far Infrared Observatory. A clone of NGST that will operate at far infrared wavelengths, it will improve our ability to study this region of the spectrum by orders of magnitude.

The moderate initiatives recommended by the committee will provide a rich diversity of modes for observing the universe. The highest priority among the moderate initiatives is the Telescope System Instrumentation Program, or TSIP. The U.S. is unique in the world in that the the majority of the optical telescopes in this country are private, so that they are not available to the general astronomical community. In many cases, funding is not available to outfit these telescopes with the modern instruments needed to maximize their scientific productivity. TSIP will provide money for instrumentation on the private telescopes in exchange for observing time, thereby providing powerful new instruments for U.S. astronomers, access to large private telescopes by the community, and opportunities for the training of graduate students in the construction of the new instruments.

The second priority among the moderate initiatives, and the top priority for a moderate space mission, is the Gamma-ray Large Area Space Telescope. This telescope will study the highest energy radiation--gamma rays--with a sensitivity 30 times greater than its predecessor, the EGRET instrument aboard the Compton Gamma Ray Observatory. It will study jets from supermassive black holes in the centers of distant galaxies and the origin of cosmic gamma ray bursts.

The third priority is the Laser Interferometer Space Antenna. This is unique among the recommended missions because it is designed to detect the gravitational radiation predicted by Einstein's general theory of relativity. It will observe gravitational radiation from close binaries in the Galaxy and from the coalescence of supermassive black holes in distant merging galaxies. It will be carried out jointly with the European Space Agency.

Next is the Advanced Solar Telescope. The largest optical telescope ever designed to study the Sun, it will observe solar plasmas and magnetic fields with unprecedented resolution in both space and time. It will provide fundamental data on why the Sun's luminosity varies with time. Construction will be carried out jointly with the Europeans.

The Square Kilometer Array Technology Development will prepare the way for an international radio telescope with 100 times the sensitivity of the VLA.
The Solar Dynamics Observatory will build upon the remarkable success of the SOHO mission to probe the structure of the Sun.
The Combined Array for Research in Millimeter-wave Astronomy will provide a powerful facility in the northern hemisphere to complement the Atacama Large Millimeter Array (ALMA) in the southern hemisphere.
The Energetic X-ray Imaging Survey Telescope will survey the sky for energetic X-rays emitted by black holes, neutron stars, supernova remnants, and gamma ray bursts.
The Very Energetic Radiation Imaging Telescope Array System is a set of ground-based telescopes that will observe extremely energetic gamma rays through the effect they have on the Earth's atmosphere.
The Advanced Radio Interferometer between Space and Earth will dramatically improve our ability to resolve the regions near supermassive black holes.
The Frequency Agile Solar Radiotelescope will provide unique information on the heating of the solar corona and the origin of the solar wind.
The South Pole Submillimeter Telescope will take advantage of the superb transmission of the atmosphere in Antarctica to survey the dusty universe and identify primordial galaxies.

The National Virtual Observatory is the top priority among the small initiatives. It will integrate all major astronomical data archives into a digital data base and develop the tools necessary to use this data base. It will make the flood of data from astronomical observatories available on the internet to both professional astronomers and the public. The committee recommended a number of other small initiatives as well, but these are not prioritized.

Most of the initiatives recommended by the committee are aimed at providing technologically advanced instruments to observers so that they can push back the frontiers of knowledge. In many cases, however, it is theorists who guide the choice of instrumentation, the decision of what to observe, and the interpretation of the data. The committee recommends that for most major and moderate initiatives, funding should be provided to support work on one or more challenging theoretical problems that are relevant to the initiative.

OPTIMIZING THE RETURN ON THE NATION'S INVESTMENT IN ASTRONOMY AND ASTROPHYSICS

The committee made a number of recommendations designed to ensure that our nation gets the most out of its considerable investment in astronomy and astrophysics.

The committee reaffirms the recommendations of the Bahcall Committee by endorsing the completion of the Space Infrared Telescope Facility, the Millimeter Array (now part of ALMA), the Stratospheric Observatory for Infrared Astronomy, and the Astrometric Interferometer mission (now called the Space Interferometry Mission).

To achieve the full potential of a new facility, it is essential that, prior to construction, funds must be identified for operations, renewal of its instrumentation, and for grants for data analysis and development of associated theory.

New initiatives should not be undertaken at the expense of the unrestricted grants program.

The committee recommends that all ground-based optical/infrared telescopes, whether public or private, should be viewed as a single system; the same applies to radio telescopes and to solar telescopes. Effective national organizations are needed to coordinate and ensure the success of these systems.

Cross-disciplinary, competitive reviews should be held about every 5 years for all NSF astronomy facilities, with prioritization and possible closure or privatization as standard policy.

The Department of Energy should develop a strategic plan that would facilitate coordination and cooperation with other agencies on science of mutual interest.

NASA should continue to encourage the development of a diverse range of mission sizes, including small, moderate, and major. In particular, the committee has recommended a number of moderate NASA missions for the coming decade.

The multi-wavelength, interdisciplinary studies that are often needed to understand astronomical phenomena can in some cases be done only through interagency cooperation. The committee recommends that each agency that supports astronomy and astrophysics---NASA, the NSF, and DOE--should have a strategic plan for astronomy and astrophysics, and it should have advisory committees available to evaluate possible interagency collaborations.

International cooperation enables the U.S. to participate in large "world observatories'' and to participate in major projects led by our international colleagues. International collaboration is essential for many of the initiatives recommended by the committee.

Astronomy is of great interest to both students and the general public, and as a result astronomers have the opportunity to make a significant contribution to education and outreach. The committee's most important recommendations in this area are:

Improvement of the opportunities for astronomers to engage in outreach to the K-12 community;
Establishment of partnerships between departments of astronomy and education at a few universities in order to develop exemplary science course for pre-service teachers;
Improvement in coordination among federal programs funding educational initiatives in astronomy; and
Improving the public understanding of the achievements of all NSF-funded science and facilities. Because of its broad public appeal, astronomy could provide a starting point.

Let me reiterate the sentiments expressed by my Co-Chair, Joe Taylor: We were very fortunate to have an outstanding and dedicated group of astronomers and astrophysicists who worked with us for almost two years to produce this report. The result of this effort is an ambitious vision for astronomy and astrophysics in the first decade of the new millennium. The initiatives recommended by the committee have the potential to transform our understanding of the universe.