Summer 2001 • Volume 18, Number 2

SPACE TELESCOPE SCIENCE INSTITUTE Highlights of this Issue:

¥ Interview with Bruce Margon —page 5 ¥ Cosmology’s Heart of Darkness —page 7 ¥ Hubble Status & Prospects —page 17

New Proposal Opportunities in Cycle 11 Duccio Macchetto, [email protected], Georges Meylan, Letizia Stanghellini, Roeland van der Marel, & Robert Williams

he Call for Proposals for Cycle (NICMOS) will be revived during Complementing the evolving tech- 11 has been released in early SM3B through the installation of a nical capabilities of the telescope, TJune, with the proposal dead- cryocooler, which should restore its STScI is offering several new proposal line set for Friday, 7 September 2001, detectors to full sensitivity. This will opportunities in Cycle 11. At the 8:00 pm EDT. Cycle 11 will bring provide Hubble with a renewed near- request of NASA, STScI convened a many new exciting opportunities for IR capability, the power of which was committee with members from the scientific research. We are launching recently illustrated by the ground- astronomical community to develop the Hubble Treasury Program for large breaking study of a supernova at red- plans to optimize the scientific return projects producing multiple-use data shift 1.7 using NICMOS observations from HST in its second decade of sets and a Hubble Theory Program to extracted from the HST data archive. operations. This Hubble Second Decade improve the basis for interpreting HST The Wide Field Planetary Camera 2 Committee recommended that a new observations. Cycle 11 also offers the (WFPC2), the Space Telescope Imaging program be created to stimulate science most powerful combination of instru- Spectrograph (STIS), and the Fine from HST that might not naturally be ments since the launch of Hubble. We Guidance Sensor (FGS) will also contin- encouraged by the existing process, and encourage our community to take full ue to be available during Cycle 11. The in particular, to stimulate the creation advantage of this competitive opportu- upcoming cycle will therefore provide of important data sets that one would nity for time on Hubble at its best. Hubble with the broadest and most sen- regret not to have obtained when HST All programmatic and technical sitive capabilities since it was launched. continued page 4 information for proposers, as well as specific guidelines for proposal prepa- ration, are available electronically Meg Urry from the STScI announcement web Leaves STScI site, http://www.stsci.edu/ftp/propos- er/cycle11/announce.html. Questions We thank Meg Urry can be addressed to the STScI Help for her outstanding Desk (email: [email protected]; phone: leadership of the Hubble 410-338-1082). science program selection The next servicing mission (SM3B) process in the past years. is currently scheduled to occur in Meg is leaving STScI for a early 2002, well before the nominal professorship at Yale, and start of Cycle 11 in July 2002. The we all wish her all the best Shuttle astronauts will install the in her future endeavors! Advanced Camera for Surveys (ACS), which consists of three electronic cameras and a complement of filters and dispersers. ACS will increase HST’s discovery efficiency—defined as the product of detector efficiency and field of view—by a factor of ten. It is expected that the Near Infrared Camera and Multi-Object Spectrometer Newsletter • Space Telescope Science Institute

DIRECTOR’S PERSPECTIVE

Steven Beckwith

Big Problems, Big Time

colleague recently sat in my office and explained how he had put in two proposals for HST time, one for 70 orbits and another for 50 orbits, specifically to avoid the dreaded “triple-digit” request. It turns out he was misinformed. The Achances of getting an HST program approved in Cycle 10 were actually better (statistically) for 100+ orbit proposals than for proposals between 50 and 99 orbits, thanks in large part to Meg Urry and her innovative approach to structuring the HST peer review. No matter, he got the time anyway (sometimes you beat the odds), but it pointed out a problem we astronomers have with big programs. A similar concern for size arose in a conversation about measuring the acceleration of the universe using distant supernovae as standard candles in a classic Hubble diagram. HST is capable of finding supernovae at redshifts as large as 2, as Ron Gilliland, Adam Riess, and their colleagues recently demonstrated to wide acclaim (Gilliland et al. 1999, Ap.J., 521, 30; Riess et al 2001, Ap. J., in press, astro-ph/1014455). Supernovae at redshifts between 1 and 2 record the universe’s expansion history in that important epoch and can help us decide if they really are standard candles. If we built up a sample of a few tens of such supernovae, we might begin to tease out that history sufficiently well to distinguish between various forms of quintessence and determine whether the dark energy was Einstein’s cosmological constant or something else that now dominates the cosmos. HST could conceivably prove that the universe was quintessential—oh, what a press release that would make! It would cost a few hundred orbits of HST observing time, about 10% of a year’s allocation, about the amount that the Director has at his discretion. But since less than 10% of the fields observed are likely to have supernovae at any time, the low yield would make it difficult to get the time through peer review. Our colleagues in particle physics would wonder what the problem is. They are used to directing enormous enterprises aimed at getting one physical constant or one new particle critical to testing a prevailing theory. There is little doubt that a clear proof of dark energy and a demonstration that it is the cosmological constant, say, and not some other form would be a profound intellectual achievement for astrophysics. But in our present system of time allocation, a few hundred orbits all at once are difficult to come by even with the new TAC procedures. We tend to divide up our resources so as to satisfy the largest number of people. Yet keeping our science vital by demonstrating the capability and will to resolve big problems is also a matter of interest to us all. Programs above some threshold can sometimes solve several scientific problems at once, although they are rarely proposed. A workshop at the Institute in March brought together astronomers with many different interests to examine how a large survey with the new Advanced Camera for Surveys (ACS) might address different fields of astronomy. Groups interested in the evolu- tion of galaxies, active galactic nuclei, the measurement of cosmological parameters, mapping dark matter, and measuring Galactic structure met separately to propose surveys that would address the major questions in their respective areas. Remarkably, almost every group came up with separate surveys that, except for minor details, looked the same. An epiphany occurred on the final day when we all realized that a single large survey might address simultaneously the burning questions in at least four fields of extra-galactic astronomy. I suspect similar synergisms exist between other fields not present at that workshop. It is apparent that there is important science requiring hundreds of orbits of HST. Much of this science will need to be done rather soon after the new instruments are installed during future servicing missions. The charge transfer efficiency of CCD detectors deteriorates on orbit over a few years as a result of radiation exposure. Programs requiring the greatest sensitivity should be done at the outset. Of course, almost all programs push our instruments to their limits. Yet it would be hard to argue that a program to measure the cosmological constant, say, or to pick out the faintest galaxies in the deepest HST field, is of only passing interest and should wait until everyone has had a chance to look at his or her favorite targets. We need to do some things now because they have far-reaching implications for astronomy or physics. Largely for this reason, we introduce the Hubble Treasury Program in the Call for Proposals for Cycle 11. The Treasury Program is patterned after the SIRTF Legacy program, for which the goal is to gather large data sets of lasting importance to astronomy and which need an up-front investment of a lot of telescope time. Because these programs are a public resource, there will not be proprietary rights to the data. The successful teams will have to produce data products in short order for all scientists to share. Through the Treasury Program, we hope to tackle some of the big problems as a community. continued page 3

2 Summer 2001

The ACS High-Latitude Survey Workshop Harry Ferguson, [email protected]

he Advanced Camera for colors, sizes, and clustering properties survey would address compelling Surveys (ACS) will improve of objects in the distant universe to needs in many subdisciplines of Tthe survey efficiency of HST test theories of galaxy formation. astronomy. There was also great by roughly a factor of ten. ACS Image shear statistics and the enthusiasm for going forward with an images of “clean” lines of sight at incidence of multiply-imaged sources ultradeep field, pushing roughly a high Galactic latitude are likely to be could test cosmological models and factor of 10 deeper than the HDF at of great utility for a wide variety of hierarchical structure models. The optical wavelengths. science investigations. A workshop statistics of point sources could in A strawman wide-area survey was held at STScI March 22-23, 2001 principle provide information on would have 1-2 orbits depth in the to stimulate discussion of science Galactic structure and baryonic dark Sloan g', r', i', and z' filters and would goals and observational strategies for matter. High redshift supernovae could cover a total of 1000-2000 square such high-latitude surveys using ACS. place constraints on cosmological arcminutes divided over 5-10 fields. The ACS survey workshop had two parameters and on the evolution of Such a survey would complement the aims. First, to gather interested supernova rates with look-back time. capabilities of the wide-field multi- astronomers from diverse fields to To place workshop initiatives in object spectrographs coming online at discuss science goals and identify context, outlines of the ACS GTO Keck and the VLT, as well as covering areas where observing requirements program and the default program of areas compatible with deep surveys might overlap. Second, to explore parallel observations were presented. from SIRTF and Chandra. Such a interest and possible strategies for a Complementary high-latitude surveys survey would provide high-resolution public ACS survey—akin to the Hubble from other facilities or at other wave- morphologies and accurate photome- Deep Fields—that could be carried out lengths were reviewed. The technical try for samples of galaxies one to two using Director’s Discretionary Time. characteristics of ACS and scheduling orders of magnitude larger than exist- A series of talks highlighted the issues were discussed. ing surveys, enabling a much more major scientific issues that could be After splinter groups firmed up precise mapping of galaxy evolution addressed with ACS surveys. Topics observing requirements and priorities from redshifts z>3 to the present day. included cosmology, galaxy evolution, in different scientific areas, the discus- If the PSF is stable enough, such a high-redshift supernovae, active sion centered on two possible kinds survey would also provide a measure- galaxies, and Galactic structure. ACS of surveys. There was remarkable ment of cosmic shear due to weak survey images could determine the consensus that a wide-area, multi-band continued page 6

Big Problems from page 2

Discovering supernovae at redshifts beyond 1 is a tricky problem. The low yield of a dedicated search program would mean that more than 90% of the data would be useless for the proposed science. We can tackle this problem by making our programs multipurpose, a bit like the survey described above. We need to search for supernovae in deep images of the sky which we take for other purposes: to study distant galaxies, to measure gravitational lenses, or to follow gamma-ray bursters, for example. If we split the observations of each field into two sessions separated by about a month, we could find supernovae that erupt in those fields while also getting useful data for an entirely different program. No observations would be wasted, and we would discover some supernovae well-suited to measuring the geometry of the universe. Because it is important to develop this methodology, the Institute is starting a pilot program to leverage approved observa- tions calling for deep I band images of high latitude fields. We will observe these fields twice and look for supernovae in distant galaxies. It will take some experiments to figure out the best methods for rejecting false positive signals Ð from transient hot pixels, for example Ð and to refine our knowledge of the yield per observation. By the time ACS and NICMOS are available next year, we will be well placed to measure the magnitudes and colors of distant supernovae throughout their light curves, using them as standard candles to map out the geometry of spacetime. As you prepare your observing proposals for Cycle 11 this fall, consider dual-use science. You may find that dual-purpose observa- tions will have an irresistible appeal to the TAC, especially in cases where the primary science is below the cutoff for approval.

Steven Beckwith Baltimore, June 7, 2001

3 Newsletter • Space Telescope Science Institute

Proposal from page 1

is ultimately decommissioned. large, homogeneous data sets, we wish A Theory proposal, like an AR (http://sso.stsci.edu/second_decade/ to stimulate more ambitious AR pro- proposal, must request a specific recommendations/index.html) In grams of direct benefit to the scientific amount of funding and must describe response to this recommendation, community. To this end we have creat- the proposed use of the funds. Award STScI has formulated the new ed the AR Legacy Program. amounts are anticipated to be similar Hubble Treasury Program. A Legacy AR proposal should per- to those for regular AR proposals, The Treasury Program is structured form a homogeneous analysis on well- although STScI does allow the sub- to provide crosscutting, public science defined data sets in the HST archive mission of more ambitious proposals data analogous to the Hubble Deep and should provide data products to for which larger amounts of funding Fields and the SIRTF Legacy pro- the scientific community (catalogs, may be justified. Theoretical research gram. A Treasury project should focus software tools, web interfaces, etc.) to should be the primary or sole empha- on the potential to solve multiple sci- allow a variety of new investigations. sis of a Theory Proposal. Analysis of entific problems with a single, coher- It is anticipated that Legacy AR pro- Archival data may be included, but ent data set. It should enable a variety posals will be larger in scope and should not be the main aim of the of compelling scientific investigations. funding than regular AR proposals. project. Funding for GO or AR Enhanced data products are an essen- They will be allowed to extend over proposals in which theoretical tial component of the Treasury multiple cycles. research is included but not predomi- Program, to encourage adding value to In all AR proposal categories, nant will remain appropriate under the data (reduced images, object cata- STScI encourages projects that com- the regular GO or AR programs. logs, collaborative observations on bine HST data with data from other Recent trends in HST funding suggest other facilities, etc.). Like the Hubble space missions or ground-based obser- that of order 5% of the total HST GO Deep Fields, the data will be non-pro- vatories, consonant with ongoing Funding might be used to support prietary, and immediately available to all. efforts to create a National Virtual Theory Proposals. Treasury projects are expected to Observatory (NVO). A more subtle change in the STScI require large numbers of orbits. They Another important change in Cycle proposal protocol is a widening in the will be reviewed by the Telescope 11 is the start of the HST Theory scope of the use of Director’s Allocation Committee (TAC) together Program, which will be funded as part Discretionary (DD) time. In the past, with ‘large’ GO proposals (>100 of the HST AR program. The Theory DD time was generally not awarded if orbits). It is anticipated the TAC will Program responds to the recommenda- the proposed observations could have award a total of up to 1200 orbits per tions of the recent Decadal Survey been anticipated as a Target of cycle to proposals in the Large and Committee, which stressed the impor- Opportunity program or could be Treasury categories (approximately tance of funding theoretical research in taken in the next regular review cycle. 1/3 of the total time expected to be conjunction with major facilities. Recognizing the limited lifetimes for available in Cycle 11). Since Treasury A Theory proposal should address a major space facilities such as HST, projects can extend over multiple topic of direct relevance to HST obser- Chandra, and SIRTF, proposals for cycles, a Treasury project requesting vational programs, and the results rapid follow-up of new discoveries 1000 orbits is conceivable. should enable new types of investiga- will now be considered even if the The emphasis in Cycle 11 will be tions using HST or HST data in the astrophysics of the phenomena do not on observations whose value will be archive. Also, funding of mission-spe- require such rapid follow-up. greatest if taken soon. STScI recently cific research will be favored over However, proposers must demonstrate organized a workshop to explore ideas research that is appropriate for a gener- that the observations will provide a for deep surveys with ACS (see relat- al theory program (e.g., the NASA critical link in the understanding of the ed article on page 3), and such surveys Office of Space Science Astrophysics phenomena and that carrying them out could certainly fit well in the Treasury Theory Program; ATP). The primary quickly is particularly important for category. However, proposals on other criterion for a Theory Proposal is that planning future observations with topics are equally encouraged. the results should enhance the value of major facilities. The primary criteria We are also adding a new proposal HST observations through broadened for DD proposals will continue to be opportunity to the Archival Research or otherwise improved interpretations. extremely high scientific merit and a (AR) program, which has been active For example, Theory projects might strong demonstration of the urgency of since the early cycles of HST. Awards develop new models or theories to the observations. for funding of ‘regular’ AR proposals refine our knowledge or improve our We wish to emphasize a number of has typically been under $100,000, understanding of specific data sets. other proposal opportunities, although with a median around $50,000. Given The results of the theoretical investiga- they were already offered in one or the rate of increase in the size of the tion should be made available to the more previous cycles. HST data archive and of the value of community in a timely fashion. 4 continued page 7 Summer 2001

An Interview with Bruce Margon Bruce Margon, [email protected]

r. Bruce Margon is the new How do you see the analogy ward to accomplish this goal are Associate Director for between the Institute science sometimes subtle. We cannot expect DScience at STScI. He is a for- staff and the faculty at a university, the community to have the time nor mer Professor and Chair of Astronomy in terms of opportunities, responsi- in most cases the specialized expertise at the University of Washington and a bilities, and pressures? to think strategically about how best to former Chair of the AURA Board of use the very valuable assets entrusted Margon: My many university col- Directors. Currently, Bruce chairs the to us, so it’s our responsibility to be leagues may not love me for saying the Structure and Evolution of the creative. Science initiatives like the following, but I have to remark that in Universe Subcommittee of NASA’s Hubble Deep Field and the recent the area of pressures, I have in my Space Science Advisory Committee program to find very distant SN are three decades since graduate school and is a member of the NGST Interim examples that come to mind. Science Working Group. His research What is Hubble’s greatest has emphasized high energy astro- achievement? What is its most physics. Bruce kindly agreed to be underrated contribution? What do interviewed for this Newsletter. you foresee as Hubble’s ultimate Your position of Associate Director mark on the history of science? for Science is a new job for both Margon: This is a bit like asking “what you and the Institute. What is your is the best movie ever made?”: there vision? What are your priorities for could hardly be a more subjective improving both Institute science query. And like most other things in and mission science? astronomy, there are few problems Margon: The role of the Institute’s where 100% of the credit goes to service to the community has always HST; inevitably other facilities have been quite clear to those both inside played major roles. With all those and outside STScI, as well it should qualifiers, I’d personally pick from a be. But the role of scientific research short list of the ubiquity of black holes within our walls has perhaps been less in galactic nuclei, the dominant role clearly articulated over the years, and of the diffuse IGM in the universal benefits from having a champion. baryon budget, and initial observations never before been surrounded by so World class research has been con- of white dwarfs in globular clusters. many consistently hardworking col- ducted at STScI virtually from the In the “underrated” category I place leagues. The pressures of very real day of its founding, both by internal several of STScI’s contributions to our deadlines—and dozens of them, large staff and often in external collabora- discipline’s modern infrastructure, and small—are far more severe than tions. It’s not in conflict with our for example the Guide Star Catalog, most university tasks. But they are service responsibilities, but indeed which habituated much of our com- nicely offset by the rewards and enhances our ability to perform them, munity to digital astrometry for the opportunities. The infrastructure for by providing an environment that first time, and SPIKE. The ultimate research and public outreach at attracts and retains the very best staff, mark on the history of science? Not STScI is simply outstanding—simply and giving us a “user’s” rather than just that big science normally does the best of any place I have been “operator’s” perspective. It’s an fulfill its promise, but the wonderful privileged to work. argument not dissimilar to why uni- energizing of science that results versities want teachers who are also What is your view of the when only scientific merit rather than performing front line research. So my relationship between the Institute institutional affiliation acts as a gate- goal is certainly not to start or enable and the community? How can we way to the best facility. And, finally, such an environment—it’s flourishing increase our value and useful- I’d have to say, it’s “Casablanca.” already—but rather to try to optimize ness to the community? In what ways do you think NGST will and enhance it, and help it evolve into Margon: We exist to serve the com- be qualitatively the same or different the Institute’s new multi-mission role. munity, period. If we ever lose track from Hubble as a phenomenon? Recruiting and retaining the best of that simple fact, we’re in trouble. young people as we transition Margon: It’s a lot easier to see the sim- But with enterprises as complex as from HST to NGST is one obvious ilarities at this stage, until the HST and NGST, the best ways for- challenge we face. continued page 8 5 Newsletter • Space Telescope Science Institute

First Spring Symposium Webcast Carol Christian, [email protected]

or the first time, scientists rotation curves. Several participants before the “Big Bang” — from a around the world could “virtually” who were unable to attend the full presentation featured on the 3rd day of Fattend the Space Telescope proceedings enjoyed the ability to the symposium. Most webcast viewers Science Institute’s Spring Symposium access the live webcast from their were located in North America, but from their offices. Using their com- offices back home. A few users at several scientists from Britain, the puters and taking advantage of new universities set up computers with Netherlands, Italy, Sweden and ‘webcasting’ technology, listeners projectors for classroom viewing. Mexico also tuned in. For some tuned in during the Dark Matter Others caught a few talks in between presentations, the webcast increased Symposium held April 2-5 to hear classes and meetings. Local users the audience by a third over the authors present the latest research on could multitask, listening to the participants who traveled to the aspects of dark matter, dark energy, presentations from their offices. Institute for the symposium. and theories of gravity. The webcast Viewers responded positively to the Our DTI group uses audio/video was arranged by the Development, webcast and provided valuable feed- streaming technology (webcasting) to Technology & Innovation (DTI) group back for improvement. One user com- broadcast conference proceedings on the at STScI, which believes webcasting mented that the symposium webcast Internet. We serve the video stream with can augment the accessibility of was “an unexpected opportunity”, but software from RealNetworks, and users astronomical research and associated remarked that a time zone difference can view each presentation with the technology for scientific, technical, caused him to lose some sleep in order free RealPlayer client. In collaboration and public audiences. to listen in. Luckily our archive contains with the Science Division at the On the first day of the conference, all the presentations for later viewing. Institute, we offered the webcast on an Dr. Renzo Sancisi was delighted to The BBC online science editor experimental basis in order to evaluate receive email from Australia and the highlighted the new theory for the the facility for future use. We wanted Netherlands in response to his talk on origin of the universe — the time continued page 9

ACS from page 3

lensing, probing smaller scales than chosen lines of sight. However, was borne out in practice with the possible with current ground-based fields at b=30¡ are not ideal for HDF, which has had an impact in surveys, and potentially identifying extragalactic work, so it is not obvi- diverse areas of astronomy unanticipated mass concentrations purely on the ous that all of the science goals can at the outset of the project. basis of their ability to bend light. be met with one survey. STScI Director Steve Beckwith With careful scheduling, the survey A strawman ultradeep survey would closed the meeting by expressing the could also be made “supernova be a single 11 square arcminute field view that the deep survey option was friendly,” identifying candidate type observed for roughly 300 orbits in more compatible with the use of Ia supernovae at z>1 for follow-up g', r', i' and z'. While there are clear Director’s Discretionary Time, both confirmation. Such a wide-area science goals, such as improving con- because the observing requirements survey would also provide vital infor- straints on faint galaxy morphology do not break the bank, and because mation on AGN demographics, partic- and on the low-surface-brightness its inherently risky nature makes it ularly in conjunction with Chandra extent of high-redshift galaxies, in less likely to succeed through the and SIRTF observations, and on the general the science motivations for normal TAC process. The shallow demographics of the host galaxies. such a deep survey are more specula- survey, on the other hand, is an There was consensus that the tive. Much of the allure of the project example of something that could be fields for a wide-area survey should is the potential that an order of magni- considered for the Treasury Program be well-studied regions of low tude in depth could bring unexpected (see related article). He encouraged extinction and low cirrus, with care discoveries or insights. History sug- the meeting participants to continue taken to avoid bright stars and bright gests that leaps of an order of magni- the dialogue and to move forward in radio sources. Studies of Galactic tude in observing capability often yield defining large, coherent surveys that structure would benefit from high- major breakthroughs, many of which could make the best use of ACS in resolution data over several carefully were not anticipated beforehand. This its early years.

6 Summer 2001

Proposal from page 4

It is possible to request collateral It is possible to request observing We continue to solicit proposals observing time on the Chandra time on NOAO telescopes (except in the categories of ‘calibration Observatory in an HST proposal. By Gemini) in an HST proposal, if both programs’ and ‘innovative pro- agreement with the Chandra X-ray the HST and the ground-based data grams’. The former aim at provid- Center (CXC), STScI will be able to are required to meet the science goals ing new or improved instrument award up to 400 kiloseconds of of the project. Under agreement with calibrations or calibration software, Chandra observing time. Similarly the NOAO, approximately 15-20 nights and the latter explore new ways of CXC will be able to award up to 100 per telescope per year will be made using HST. orbits of HST time to highly rated available to HST proposers on most We continue to encourage the Chandra proposals. The only criteria NOAO telescopes. This opportunity community to identify exciting HST above and beyond the usual review was considerably undersubscribed science that would be enabled by criteria are that the project have a when it was first offered in Cycle Target of Opportunity proposals with a fundamentally multi-wavelength 10, and we therefore encourage 2-day (or less) turnaround time, and to nature and that both sets of data be proposers to make best use of this submit proposals accordingly. required to meet the science goals. important opportunity.

Cosmology’s Heart of Darkness Stefano Casertano, [email protected]

ark matter—mass inferred The standard cosmology is a tripar- the hint of a supersymmetric particle— from gravity but yet invisi- tite view of the Universe, in which possible dark matter components. Dble— has played a role in normal (luminous, baryonic) matter Theoretical talks explored varia- science at least since 1845, when coexists with strange (dark, non- tions of the standard cosmology as the position of Neptune was baryonic) matter and a weird energy well as truly exotic possibilities. We inferred from the peculiar orbit of density called “dark energy”, both have known for some time that a Uranus. On a later occasion, new hypothesized. Dark energy is needed simple change in the laws of gravity physics, Einstein’s General Theory to accelerate the expansion of the can explain galaxy dynamics with no of Relativity, correctly explained universe, and is not associated with need for dark matter. However, this the perturbations of Mercury’s any observed structures. Thus, we are change has not yet been applied to orbit, and the mass of hypothetical invited by the standard cosmology the dynamics of the universe on a planet Vulcan was not required. and the observations it explains to cosmological scale. At the sympo- A recent Institute symposium accept the existence of two otherwise sium, it was suggested that variants updated the concept of “darkness” unseen and undetected major compo- of superstring theories could explain and the interplay of unseen nents of the Universe, neither of the flatness of the universe and the mass and mysterious forces to which is understood in terms of fun- apparent dark energy as a conse- explain observations. damental physics. Is this really the quence of extradimensional physics. Over 140 astronomers and physi- correct explanation? Or should we Inspired by the cross-disciplinary cists gathered at the symposium rather look for a radical change of the flavor of the symposium, theoretical “The Dark Universe: Matter, physical laws that govern cosmology? physicists indicated some possible Energy, and Gravity” on April More than half the talks were observational consequences of these 2-5, 2001. They discussed recent reviews of the astronomical evidence new theories. It was also suggested advances in observational cosmolo- solidly supporting the standard cosmol- that the remarkable coincidences gy, including evidence for a myste- ogy. Remarkably diverse, this evidence built into the standard cosmology rious “dark energy” pushing the is derived from observations of galaxies may be necessary so that universe apart while dark matter and clusters, weak lensing, supernovae, observers—we, that is—can exist, pulls it together. They struggled and the fluctuation spectrum of the cos- which is the key element of the with a key dilemma: whether the mic microwave background, and it is anthropic principle. standard cosmological model is further strengthened by a new result Two summary talks were presented, correct, despite its ad hoc “dark” presented at the Symposium (see side- from the point of view of a physicist components, or whether radically bar). Physicists described recent results in and of an astrophysicist. They cap- new laws of physics are needed to particle physics, including the non-zero tured well the dilemma at hand: on explain observations. mass of least two neutrino species and one side, the strength of the data and

continued page 11 7 Newsletter • Space Telescope Science Institute

Hot Summer for a Cool Telescope Pete Stockman, [email protected], Nino Panagia

he summer of 2001 is develop- Following several years of detailed ing as an important season for study when the design of NGST has Key NGST Level 2 Tthe Next Generation Space been in flux, the aerospace firms Requirements: Telescope (NGST), the cooled tele- competing to be the NGST prime con- scope that is Hubble’s successor and tractor will propose realistic observato- NGST Primary Mirror Area ≥ meant to observe the early universe ries that they will affirm can be built Unobscured area 25 square meters at infrared wavelengths. Feasibility within the cost and schedule constraints. study is ending; big procurements are In March 2001, NASA announced NGST Optical Throughput launched; international agreements its intention to issue a sole source At λ=0.6 µm > 50% have been reached; and science and proposal request for the Association At λ>2 µm > 88% technology efforts are proceeding of Universities for Research in apace. As its circle of involvement Astronomy (AURA) to provide the NGST Instruments: widens and momentum builds, Science Operations Center at STScI. Visible/near-infrared camera µ NGST is taking shape—as a mission, International Agreement on ¥ 0.6-5 m wavelength ¥ 16 (8m/D)**2 sq. arcmin a team, and an activity. Instrument Responsibilities In the current schedule, the con- field of view NASA, the European Space Agency struction of the NGST telescope will (ESA), and the Canadian Space Near-infrared multi-object start in spring 2004. The instruments Agency (CSA) have agreed upon their spectrograph will be installed and integrated start- respective contributions to the three ¥ 1-5 microns wavelength ing in fall 2007 for launch readiness ¥ R = 5,100, 1000 NGST science instruments, which are in December 2008. ¥ 9 (8m/D)**2 sq. arcmin a visible/near-infrared (0.6 to 5 field of view Milestones microns) camera (NIRCAM), a near- The NGST Project is formally infrared, multi-object spectrograph Mid-infrared camera/ completing its Phase A study of the (NIRSPEC), and a mid-infrared cam- spectrograph µ feasibility of the NGST mission. This era/spectrograph (MIRSPEC/CAM). ¥ 5-20+ m wavelength ¥ R=3, 1500 Based on these international agree- milestone sets the stage for the next ¥ 4 (8m/D)**2 sq. arcmin steps, establishing the detailed costs ments, important steps are now under field of view and actually developing the flight and way to determine the detailed capabil- ground segments in Phases B, C, and ities of these instruments and the indi- (D is the diameter of the D. NASA has begun the major pro- viduals and organizations that will primary mirror in meters) curements, which should be conclud- build them. ed by next winter. These procure- A team led by a U.S. Principal ments will include selection of the Investigator (PI) will develop initially, and one will be confirmed prime contractor for the NGST mis- NIRCAM, and CSA scientists will to build the instrument after Phase sion, the contractor for the Science participate. NASA will issue an A. (See accompanying article on and Mission Operations Center, and Announcement of Opportunity (AO) page 11.) In another development, Phase A studies for the main science this summer for competitive Phase continued page 10 camera (NIRCAM). A studies. Two teams will be selected

Margon from page 5

“gotchas” emerge on-orbit and show and mid-IR! But this will be a quite What do you see as the key us the differences. I for one hope that natural evolution from the wonderful aspects of the Institute’s transition the astronomer’s interaction with results we expect from SIRTF. from Hubble to NGST? NGST will appear essentially identical Another pleasant difference will be in Margon: Keep it simple, don’t reinvent to HST, so there is almost no commu- scheduling and efficiency, something unless essential, maximize the nity learning curve, but rather we leap that will impact each and every resources that maximize the scientific straight to the science. The differences? observer: we’ve waited for a very long results, and inform and enthuse the The average astronomer is going to time to leave low Earth orbit. public. Pretty basic stuff, actually. become a lot more facile in the near

8 Summer 2001

Symposium from page 6

to explore the potential of webcasting such as the Dark Matter Telescope We in DTI are continuing our stream- for the scientific community based (http://www.dmtelescope.org/) and ing experiments not only for workshops on our successful experience web- the press release material from Dr. and conferences but also for unusual casting public events. Adam Riess’s research on super- events, such as the visit of the Hubble We released the archive of the novae (http://oposite.stsci.edu/ Servicing Mission astronauts and web- live presentations and contributed pubinfo/PR/2001/09/index.html). cast tours of the Institute flight opera- viewgraphs through the DTI web- The archive complements the print- tions area and the Goddard Space Flight page (http://dti.stsci.edu) on May ed symposium proceedings planned Center Hubble Clean room. We look 3. The viewgraphs are derived from for publication later this year and forward to more ambitious trials using either an electronic presentation or opens the door to a new realm of collaborative streaming technologies, scanned hardcopy. Several authors scientific and technical electronic which will enable wider and better par- contributed links to other resources, publishing from the Institute. ticipation in conferences and workshops.

The Day Superman Saved ST Dave Soderblom, [email protected]

he phone call came out of the the public and so wasn’t getting blue that fine February after- political support. The politi- Tnoon. In an earlier Newsletter cians asked rhetorically I had asked for stories on the history whether the ‘man on the of HST, hoping for nuggets that street’ cared or not. could help a younger generation of “I was taking the Eastern astronomers understand how our Shuttle back to New York and Space Telescope came to be conceived happened to sit next to a kid of, built, and launched. What I ended reading a Superman comic up with that day was a small gold mine. book. The little light bulb went The caller was Pete Simmons, now on. I recognized that Superman retired, living in Colorado, and still an presented technological active proponent of the telescope in advances all the time in ways space that he helped to engender. We that caught the attention and talked for a long time and I learned a imagination of a broad audience. lot of details about HST’s early days “A few calls were made, and that I hadn’t heard before. One of the the head of DC Comics came gems was his telling of how Congress to visit Grumman on Long Island to was persuaded of the public’s interest learn more. As a result, Action Comics in space astronomy. The following in December 1972 featured a fifteen- account in Simmon’s voice is based page story with a space telescope as on the notes I took that day. the centerpiece. It may look hokey “It was ‘Space Telescope’ then, long now, with Superman wiping cosmic before the ‘Hubble’ was added, and it dust from the main lens, but I got 500 was far from clear it would ever be copies and went back to Washington so that the politicians could see for Publications, Inc. National Periodical built. I [Pete Simmons] was work-  ing for Grumman, in a division that themselves that a space telescope was responsible for the Orbiting was very much in the public eye.” Astronomical Satellites (OAO series). Did Superman save the day? I had just been in Washington trying A great deal of effort was made by to convince members of Congress of many people in those days to keep the value of a bigger and better optical the concept of a large optical tele- telescope in space, but was told scope in space alive, but the Man repeatedly that it mattered little to of Steel surely played his part.

9 Newsletter • Space Telescope Science Institute

Telescope from page 8

NASA has removed the guider concept of a mid-infrared instrument plates” or aperture masks, observers function requirements from NIR- for NASA HQ review in July 2001. have obtained spectra of tens to hun- CAM. They may be provided as a Using these requirements the MISC dreds of stars, galaxies, and quasars separate item by CSA. will work with the NGST Project over fields of 1 arc minute to 1 degree NIRSPEC will be developed by (or a designated NASA center in size. NGST will be so sensitive that ESA. To support the design and team) and the ESA consortium to it will reach millions of faint galaxies development of NIRSPEC, NASA is complete Phase A technical studies per square degree, which will put over funding three technical approaches for by April 2002. The MISC will also a hundred objects in the field of remotely controlled apertures, which recommend an optimal assignment NGST’s NIRSPEC, which will be are necessary to obtain the spectra of of international responsibilities for provided by ESA. Because proven many objects simultaneously. (See design, development, and integra- ground-based solutions to multi- related article.) tion on MIRSPEC/CAM. object spectroscopy are not practical MIRSPEC/CAM will be a joint Selectable Apertures for for the cryogenic, diffraction-limited venture led by a US PI (or a NASA the NGST Multi-Object Spectrograph NGST, NASA has been seeking new center) with the participation of a ways to achieve selectable apertures Over the last twenty years, consortium of European institutions for NIRSPEC. astronomers have used multi-object coordinated by ESA. A Mid-Infrared Through internal funding and the spectrographs on ground-based tele- Steering Committee (MISC) has recent NRA, NASA has supported scopes to great advantage. Using been created to develop a prelimi- the development of three promising adjustable multi-slits, robotically nary instrument design. NASA has technologies for a selectable-aperture placed fibers, or custom drilled “plug appointed four US scien- assembly capable of pro- tists to be part of this com- viding > 100 individual mittee; the European Space apertures over a ~ 3' × 3' Agency (ESA) has provided NGST field. Two develop- four scientists from ESA ments use microelectronic member countries; and the mechanical systems Canadian Space Agency (MEMS) technology to (CSA) has designated one create arrays of mirrors that scientist. can be commanded to The MISC reflect light into or away membership includes: Fig. 1. Two types of miniature mirrors manufactured using from the spectrograph. Fig. MEMS silicon technology to provide selectable apertures 1 shows demonstration units for NIRSPEC. The two panels show demonstration units Fabio Bortoletto from STScI/GSFC and developed by GSFC (left) and Sandia Laboratory (right). Observatory of Padova Sandia Lab development Tom Green teams. Harvey Moseley Ames Research Center (GSFC) has developed Thomas Henning an alternative MEMS Friedrich-Schiller University approach, that utilizes the Sun Kwok natural strength and flexibil- University of Calgary ity of ultra-thin silicon to Pierre-Olivier Lagage make a commandable aper- Saclay ture mask. In this case, a Margaret Meixner small magnet passes over an University of Illinois array of aperture flaps and George Rieke (Chair) forces selected flaps into an University of Arizona open position (Fig. 2). The Gene Serabyn same magnet closes the Jet Propultion Laboratory flaps after the observation. Gillian Wright A joint NASA/ESA com- Royal Observatory mittee will select the most promising of these technolo- The first goal of the MISC Fig. 2. Selectable aperture MEMS technology being devel- oped by Harvey Moseley at GSFC for NIRSPEC. gies for use in NIRSPEC in is defining the science summer, 2002. requirements and instrument

10 Summer 2001

Future AO for NGST Science Investigations Hashima Hasan, NGST Program Scientist, hashima.hasan@hq.nasa.gov

he NASA Office of Space As it is currently envisaged, this AO qualified Canadian scientists on his/her Science (OSS) anticipates will solicit science investigations that investigation team. Complete details of Treleasing an Announcement involve the design and development of the Canadian contribution will be of Opportunity (AO) for Next flight instrumentation (the recommended described in the AO. Generation Space Telescope prototype is a Near Infrared Camera NASA intends to select the (NGST) Science Investigations, in (NIRCAM). The AO will also solicit instrument investigation through a the near future. Community input proposals for investigations that utilize two-step process, and the other through the NGST Interim Science data from the NGST and that also FSWG members through a one step- Working Group (ISWG) will be involve active participation in telescope process. For the instrument investi- incorporated in a draft of this AO, and facility development. The PI’s of gations, as the first step in the process which will be posted on the World all selected investigations will serve and provided that proposals of suffi- Wide Web at http://research.hq. as members of the Flight Science cient merit are available for selection, nasa.gov/code_s/future.cfm for a Working Group (FSWG). two teams will be selected and funded period of two weeks for comment The flight instrument is expected to be for a Phase A study. A down-select from the wider community before it built by a joint U.S. and Canadian team review will then occur at the end of is released in final form. The char- led by a U.S. Principal Investigator (PI). Phase A to confirm one team for the ter and membership of the ISWG The U.S. PI will be required to utilize development of the flight instrument. are posted on the Web at http:// hardware contributions from Canadian The other FSWG non-hardware ngst.gsfc.nasa.gov/iswg/. Minutes of companies worth approximately 25 M investigations selected through this the ISWG meetings will be posted $US as provided by the Canadian Space AO will not be required to undergo a as they become available. Agency, as well as include appropriately competitive Phase A study.

Cosmology from page 7

the success of the current phenomeno- Fueled by the new physics and address—new questions about cos- logical models; on the other, the unsat- new data presented, the lasting mology and how well it fostered a isfactory nature of the models and the measures of this symposium will be new level of communication many open questions that remain. how effectively it helped pose—and between astronomers and physicists.

Adam Riess of STScI presented the discovery and analysis of the most distant supernova ever found at the “Dark Universe” symposium. Supernova 1997ff, which is at redshift 1.7, was found by Ron Gilliland (STScI) and collaborators in a repeat observation of the original Hubble Deep Field. Top left: the field around the supernova with redshifts assigned to galaxies; top right: subtraction of images taken before and after the supernova. Riess and collaborators determined the light curve of the supernova from several serendipitous WFPC2 and NICMOS observations obtained at various times over several months following its explosion. Their results, presented for the first time at the symposium, strengthen the standard cosmology by removing a potential ambiguity of previous supernova results. The bottom graph shows that the brightness of the new supernova (black dot with 1-, 2-, and 3-sigma error contours) is in good agreement with the pre- diction of the standard cosmology, while it rejects the alternative explanation of dust or evolution. Together with previous supernova results (green dots with errors), the graph shows that cosmology with both dark matter and dark energy (Omega_M=0.35, Omega_Lambda=0.65) is strongly favored.

11 Newsletter • Space Telescope Science Institute

Big Improvements at the MAST Web Site Paolo Padovani (on behalf of the MAST team), [email protected]

ew design, tools, and con- These include: This results in more consistency tent have improved the web ¥ Getting Started between pages, easier maintenance, Nsite for the Multi-Mission ¥ Data Search and Retrieval and future accommodation of more Archive at the Space Telescope ¥ What’s New features, such as printer-friendly Science Institute (MAST). Now ¥ FAQ page format options and user-cus- when you visit http://archive. ¥ Data Reduction/Analysis tomized page layout. stsci.edu, you’ll find swifter naviga- ¥ Instrumentation/Operations In addition to the web site tion, easier browsing with StarView, ¥ Processing Information improvements, three new missions and a new Scrapbook feature, and ¥ Project Publications are now being offered including: the Sloan Digital Sky Survey! ¥ Papers the Sloan Digital Sky Survey (SDSS; see below), the Tuebingen Swifter Navigation ¥ Related Sites. Ultraviolet Echelle Spectrograph Most MAST web pages now offer Selecting a main menu topic often (TUES) from the ORFEUS-II mis- two menus. Along the top of each opens sub-menus of related links. Also sion, and the Guide Star Catalog page are general links to: included on the mission-specific pages version II (GSC II). is a “quick data search” option, which ¥ mission data search pages (Data) StarView Upgrades ¥ mission home pages (Missions) searches the mission database for a Recently released StarView 6.2 ¥ help contacts (Contacts) specified target name or coordinates. In the upper right corner is a site- offers users improved performance, ¥ the STScI home page (STScI) better help, and a variety of new ¥ MAST home page (MAST). wide text-search option to locate pages by topic. For example, to find features. A new combination of references to On- StarView with Visual Target Tuner The-Fly Calibration enables StarView users to search for (OTFC), type in HST observations near a position on “OTFC” and hit the sky and then to overlay the aper- return. A list of ture outlines of those observations page links contain- on a Digitized Sky Survey (DSS) ing this term will image of the field. be displayed. Existing installations will upgrade One further themselves with user permission; improvement to the new installations can be downloaded MAST home page from http://starview.stsci.edu. is the cross-wave- (Managers of centralized installa- length target tions were notified in advance of search. Users may release.) enter a target or StarView 6.2 runs under both Java coordinates, and/or 1.3 (recommended) and 1.2.2. Under select the data type Java 1.3, StarView now runs up to (image or spectra) 30% faster. and wavelength StarView help is now On the left side of each page is a second range of interest. When a target is available in three modes: menu of links. From the top MAST page, specified, the search results list the these links point to non-mission-specific first 10 observations found for each ¥ a context-sensitive help icon or cross-mission topics, such as: mission. If no target is entered, the ¥ browsable help in a separat screen returned page lists a summary of the ¥ Help With Next Step ¥ cross-mission search tools MAST missions that fit the data type ¥ frequently asked questions (FAQ) The user accesses Help With Next and selected wavelength range. ¥ software Step via the Help menu (or type The redesigned MAST web pages ¥ prepared (highly processed) data sets ^Z). This new feature analyzes your are now created dynamically, which current status and suggests your For the mission-specific pages, standard allows us to manage information likely next actions. menu items are now used when possible. content and page format separately.

12 continued page 13 Summer 2001

MAST from page 12

A small improvement offering big Spectra and mission. The data sets contain either a convenience is the availability of the Sky Images a la Carte calibrated spectrum or image for one or HST “Quick” form from the Quick MAST has unveiled its new several wavelength regions. button on the Button menu. Spectral/Imaging Scrapbook, a web tool The returned page displays a table that permits the user to peruse represen- with data set names, mission/ instrument Additional modifications and tative spectra or sky images from mis- name, and angular separation from user- improvements in StarView 6.2 include: sion data stored in the UV/optical/near- specified position. Following the table is ¥ retrieval compatibility with the IR MAST archives. The goal is to pro- a montage of spectra or sky images con- new on-the-fly reprocessing vide a broad view of MAST holdings tained in these data sets. Representative system at the HST archive over a wide range of wavelengths. This spectra and images have been selected tool is located at http://archive.stsci. according to a set of rules developed in ¥ capability to resubmit requests edu/scrapbook.html. an automated and unbiased way. The from outside StarView The Scrapbook user submits a request rules involved such parameters as expo- ¥ improved look-and-feel to the by entering either the name of a (non- sure lengths, dates of observations, and Cross Qualification and Export solar system) object or the coordinates grating/filter configuration. Table features of a sky region and specifies “spectra” To maximize its utility, the form page or “images.” The tool returns a page for submitting Scrapbook requests ¥ capability to store and restore with a table of selected data sets and includes three search options. The first queries to the retrieval tool for thumbnail spectra or images in several (default) option searches the TORS/ repeated queries wavelength regions. The thumbnails are TORI tables by coordinates within the ¥ capability to view links to preview pages, which in turn defined search radius. (Users may enter publications using contain links for access to data in FITS their own coordinates or use the SIM- MAST data sets format, publication links, and other BAD/NED name resolvers to obtain information about the data set. To date, coordinates.) The second option, useful A StarView/Visual Target Tuner the Scrapbook includes HST/GHRS, for objects in crowded fields, searches (VTT) interaction is now available for HST/FOS, IUE, HUT, and EUVE for the name returned by SIMBAD or Solaris 8 and Windows. In this major spectra, and HST/WFPC2 images. NED in the MAST catalog. The third upgrade option, StarView and the VTT The Scrapbook utilizes a pair of option searches in the TORS or TORI (from the Astronomer’s Proposal Tool Tables of Representative Spectra and tables for name entered by the user. project) are downloaded bundled togeth- Images (TORS, TORI) compiled from (This option accepts wildcards and is er. (To save on processing space, the MAST archive. These tables list all useful for objects with unusual designa- StarView and the VTT run from the data sets assembled to date for each tions, such as “NGC 4151-jet”.) same Java virtual machine, and therefore object or pointing from any MAST Even in its first version form, the must be installed as a bundled version.) Scrapbook can be used for a variety of Since StarView and the VTT are purposes, ranging from perusal of spec- both written in Java, they can tra (or sky regions) of particular objects, exchange information. For example, The Hubble Data Archive spectra of objects within a small area on the user can overlay the apertures of the sky (clusters of stars or galaxies), or relevant HST observations on the DSS now contains about 7.3 as a teaching device making use of the image of an arbitrary field. When the full population of objects (or pointings) StarView mode is active in the VTT, terabytes of data in about observed by the HST and other UV the user can click an aperture to high- 240,000 science data sets. The satellites. As this year proceeds, data light the associated data sets in the sets from additional missions (e.g., StarView results screen or results table. Archive ingests an average of HST/STIS, HST/NICMOS, HST/FOC, This is a significant improvement over FUSE, ORFEUS, UIT) are likely to be the old Overlay feature, which could 3 gigabytes per day. Currently, listed. Also, the Scrapbook lends itself only overlay the entire field of view to the addition of spectra and images for a single observations, instead of the researchers retrieve data from from other NASA data archiving centers. particular aperture for multiple obser- the archive at a rate In the future MAST intends to add vations, which is possible now. other functionalities to the Scrapbook or Future plans for StarView include 4 times higher, over 12 closely allied tools. These could include integration of catalog searches and high-dispersion spectra, comparison of data retrieval for all MAST missions, gigabytes per day. different data sets (overplotting, merg- including IUE and FUSE. ing), and conceivably coaddition of

continued page 15 13 Newsletter • Space Telescope Science Institute

Measuring Hubble’s Science Impact Georges Meylan, [email protected]

hen questioned about the The goals of this evaluation via metrics number of top astronomers (those with impact of the Hubble tools are fourfold: the highest numbers of publications Space Telescope (HST) on and citations) using HST and the num- W ¥ to provide a standard and astrophysics and the public in general, bers of astronomers, postdocs, and objective methodology to we may honestly answer, “Important, students funded through HST grants measure the scientific impact of course!” And depending on the versus other sources of financial support. of HST degree of enthusiasm, we may even Metrics Tools add, “Essential, fundamental, enor- ¥ to inform the astronomical The Institute will develop an initial mous, historical!” All these answers community and the funding set of semi-automated metrics tools to are true and justified by the numerous, agencies of HST benefits measure the numbers of scientific important studies based on HST data ¥ to improve the scientific output papers and related citations as a func- and published in professional journals, of HST by defining new scientific tion of time and integrated over time as for example, the case of the investi- policies and procedures for its since the launch of HST. gations related to the presence of utilization supermassive black holes in the cores The tools will be applicable to: of elliptical galaxies. Other justifica- ¥ to allow intercomparisons with ¥ any HST observing program tions come merely from the superb other ground-based and space pictures in numerous press releases, observatories ¥ any instrument on board HST such as the stunning image of the The Many Ways to and its various observing modes Eagle Nebula, not to mention the Evaluate HST Impact ¥ programs by size (small, amazing variety in the Hubble There are a number of available medium, large) gallery of planetary nebulae. parameters that can be applied to eval- ¥ programs by category (GO, That HST has already made uate the impact of HST observations Key Program, Archives, SNAP) a big impact is obvious. But can its on astronomical research. impact be described by numbers as ¥ any scientific category well as adjectives, which always The most important have a subjective flavor? Scientists two such parameters are: The tools will offer the option to normalize by the number of orbits need numbers, not only sentences. ¥ the numbers of publications based and/or the amount of funding allocat- Consequently, it is important for the on HST observations, numbers ed to a program. Space Telescopes Science Institute to which can be measured globally Figure 1 provides an example of be able to provide quantitative and per year or correlated to each such a tool applied to the 3,130 papers objective information about the scien- observing program tific effectiveness of HST in a way (2,225 refereed and 914 unrefereed) that can be presented to scientists, ¥ the numbers of citations generated based on HST observations that were scientific administrators, and govern- by each of the above papers published in the interval from HST’s launch to the end of the year 2000. ment officials (e.g., NASA, ESA, Such information can be obtained (The publication statistics come from AURA, STIC, STUC). This should be either directly from the Astrophysics the database created by the Institute possible now after a decade of HST Data System (http://adswww.har librarian, Sarah Stevens-Rayburn.) operations, observations, and publica- vard.edu/) or, at a cost, from the Institute The number of papers published tions, as long as one can identify the for Scientific Information (ISI) in per year is displayed as a function appropriate measure of impact. Philadelphia. The parameters should be of time since launch for each instru- measured as a function of time and cor- Objectives and Goals ment. These results illustrate how related with each observing program. The Institute’s Science Policies quantitative and objective informa- In addition to these two obvious Division has started a project aimed at tion allows a clear evaluation of the parameters, there are numerous secondary measuring the HST science impact. various successes and scientific ones, such as the number of high-impact The objective is to define and develop impacts of the different HST papers based on HST data, where the a methodology and a set of tools to instruments. Some impacts are high-impact papers are defined as the allow a reliable, standard way to subtle, others conspicuous. 200 papers in each calendar year with the measure, quantitatively and objective- There is more such information largest number of citations, as provided ly, the impact of HST observations on to come. astrophysical research as well as on by ISI. Available also are other parameters the public’s awareness of science. based on objective criteria, such as the

14 continued page 15 Summer 2001

Impact from page 14

Fig. 1. Example of a simple metric: the number of papers published per year based on data from each Hubble instrument. The dashed curve is unrefereed papers, the dot- ted curve is refereed papers, and the contin- uous curve is the sum. The three numbers in each panel are the time integrals of the cor- responding curves. The lower-right panel has a different scale along the ordinate axis, since it contains the sum for all instruments. FGS = Fine Guidance Sensors, GHRS = Goddard High Resolution Spectrograph, STIS = Space Telescope Infrared Spectrograph, FOC = Faint Object Spectrograph, HSP = High Speed Photometer, WFPC (WFPC1 + WFPC2) = Wide Field and Planetary Camera, FOS = Faint Object Spectrograph, NICMOS = Near Infrared Camera and Multi-Object Spectrograph

MAST from page 13 individual spectra. MAST will con- The SDSS data products available which could not be used for sult and consider community needs from MAST are: science surrounding bright stars, in prioritizing new applications. bad columns, and other defects ¥ image parameters: properties and SDSS Public Science profiles of all detected objects; ¥ flux- and wavelength-calibrated Archive Goes Live! positions, magnitudes, sizes, spectra in the range of 390-910 The public now has access to shapes and more (300 attributes nm at a resolution of R=1800 per object) the superb early data from the Researchers using the Sloan Digital Sky Survey (SDSS). ¥ spectroscopic parameters: red SDSS archive may choose to: STScI supports the distribution of shifts, line identifications and ¥ query the SDSS catalog in the first 490 square degrees, spectra-based classifications simple or advanced manner including 55,000 spectra, through (30 attributes per object) the MAST web site (http://archive. ¥ view and collect images of a stsci.edu/sdss/). ¥ three-color composite images particular object or region of sky SDSS uses a dedicated 2.5 ¥ flux vs. wavelength plots with meter telescope and a large format spectral features identified, and ¥ obtain catalog information for an CCD camera to image a planned other notations overlaid image or spectrum via the Sky- 10,000 square degrees of sky at Server (an interactive SDSS ¥ photometrically and astrometri- high Galactic latitudes in five browsing tool geared to the cally calibrated images in the five broad bands. The SDSS filters are geneal public) u', g', r', i' and z', centered at 354, wavebands (corrected frames with 477, 623, 763, and 913 nm, 0.4 arcsec pixels; binned images ¥ access the 1-D spectra with 1.6 arcsec pixels) respectively. The survey will also The imaging phase of the SDSS is yield medium resolution spectra ¥ cut-out pixel maps (atlas currently about 20% complete. The next for approximately 1 million galax- images), surrounding each object major data release, which is scheduled ies and 100,000 quasars. detected in the images for January 2003, will include all data obtained through July 2001. ¥ maps of regions (mask images) 15 Newsletter • Space Telescope Science Institute

Hubble Fellowship Program 2001 HUBBLE FELLOWS Howard E. Bond, [email protected] Name Host Institution ubble Postdoctoral Announcement of Opportunity, Ph.D. Institution Fellowships are awarded which will be released in late Aaron Barth Hannually to support recent summer. The application deadline UC Berkeley 1998 Caltech Ph.D.s, who will conduct research will be November 8, 2001. Applicants Elizabeth Barton in areas of observational and/or must have completed their Ph.D. Harvard 1999 U Arizona theoretical astronomy and degrees no earlier than January 1, astrophysics related to the HST 1999. The number of Hubble Fellows Martin Bureau mission. They are three-year to take up their appointments in the Austral Natl U 1999 Columbia U fellowships limited to candidates autumn of 2002 will be approximately Adam Burgasser who have received their doctoral 12. One institution, the Carnegie Caltech 2001 UCLA degrees within the past three years. Observatories (Pasadena), will be Andrew Cumming The Hubble Fellows may conduct ineligible for new Fellows in 2002 UC Berkeley 2000 UC Santa Cruz their research at a U.S. host because they accepted two new institution of their choice, subject Fellows for the current year. Mario Hamuy to the limitation of one new Hubble The Hubble Fellows come to Arizona 2001 OCIW Fellow per institution per year. Baltimore each year to present Andrew Hopkins The Hubble Fellowship selec- reports on their research projects at Sydney 1998 U Pittsburgh tion committee met most recently in the Hubble Fellows Symposium. Charles Keeton January, 2001, to consider the 124 This year’s Symposium will be held Harvard 1998 U Chicago applications that had been received October 4-5, 2001, and all interested in the autumn of 2000. The task persons are invited to attend. Jason Prochaska was made exceptionally difficult Further information about the UC San Diego 1998 OCIW by the outstanding quality of the Hubble Fellowship program is a Constance Rockosi candidate pool. vailable at our web site, http://www. Chicago 2001 U Washington The twelve new Hubble Fellows stsci.edu /stsci/hubblefellow.html, Keivan Stassun including detailed instructions for selected for 2001 are listed in Wisconsin 2000 U Wisconsin the sidebar. submitting an application and lists The Hubble Fellowship program of current and past Hubble Fellows. J. Stuart Wyithe will continue this fall with another Melbourne 2001 CfA

Institute Postdoctoral Fellowship Program Michael Fall, [email protected]

TScI supports outstanding that fellows will participate actively We plan to select another Institute young researchers through its in the scientific life of the Institute. Fellow next winter for an appointment SInstitute Postdoctoral The Fellowships include a generous to begin in the fall of 2002. Applications Fellowship Program. Institute Fellows salary, benefits, and funds for research and letters of reference will be due are selected, usually one per year, on expenses. They are intended to be on December 1, 2001. Details of the the basis of their accomplishments and equivalent to “prize fellowships” at application process will be announced promise in research in any area of other major research institutions. soon in the AAS Job Register, in astrophysics or planetary science in Current Institute Fellows are James Physics Today, and at the STScI which STScI has expertise, including Rhoads and Chris Fassnacht. Fellow- web site (http://www.stsci.edu/stsci/ theory, observation, and instrumentation. elect Oleg Gnedin will join STScI in STScI_Fellow.html). Interested per- The Institute Fellowships are for September. Recent holders of Institute sons may contact Dr. Michael Fall research alone and carry no other Fellowships include Sally Oey, Roeland for more information. responsibilities, although it is expected van der Marel, and Mark Dickinson.

16 17

INSTRUMENT NEWS Summer 2001 continued page 18 continued page keep the Hubble work- A at this time is whether the primary uncertainty It seems likely that STIS will not be restored to After a few months of relative quiet, many of us have After a few months of are all looking forward to Servicing Mission 3B in We verification, and calibration of mechanisms that verification, and calibration of mechanisms using require attention in order to switch to operation the side-2 chain. in the STIS CCD will have active temperature control future, because the side-2 thermistor used for temper- ature control of the CCD failed before launch and The suspect fuse that feeds power was not replaced. to the STIS side-1 electronics can be replaced easily during servicing, but if a short occurred, then its use The possibility of may not be possible or advisable. cross-strapping the CCD temperature control using only parts of the side-1 electronics within STIS will be investigated. In the absence of active CCD temper- ature control an on-orbit calibration program will be which are expected conducted to quantify any effects, to be quite minimal for most applications. normal science productivity for a period of 6 to 8 weeks. In the meantime observing calendars have WFPC2 observations been quickly reworked with the inclusion With replacing scheduled STIS science. had to scramble to react to the apparent blowing of a fuse had to scramble to react the STIS (see article by Paul in the power line that supplies this note, it appears that we At the writing of Goodfrooij). the STIS to service using its back- should be able to return of engineers and The team in July. up electronics sometime has once again done a remark- scientists across the project understanding the problem from able job of analyzing and the meantime, our schedulers have relatively little data. In WFPC2 prime observing time with scrambled to fill in the and have managed to keep the and SNAPshot observations, relatively high. observing efficiency ACS and should see the installation of the which January, of a mechani- reactivation of the NICMOS with installation These additions to the complement of cal cooler (NCS). the age of 12 at available instruments will result in HST, in its life- years, achieving the highest degree of capability propos- 11 time. Please feel free to inundate us with Cycle als, and we all will do our best to ing overtime to execute them. s orbit. ’ . That said, ” shift “ s facility-level ’ observing y 11 × d [email protected] [email protected] 365 ×

h ubble has been a remarkable machine, ubble has been a remarkable interruption in its with only one serious 24 spectrograph since March 1997, experienced a spectrograph since March 1997, experienced he Space Telescope Imaging Spectrograph Telescope he Space (STIS), which has been HST

The most likely explanation of the malfunction is Last fall we had a few occasions when the WFPC2 occasions when the Last fall we had a few Spectrographs Goudfrooij, Paul Hubble Status & Prospects Hubble Rodger Doxsey, malfunction on 16 May 2001. Coordinated reviews of malfunction on 16 May 2001. Coordinated have been the engineering telemetry across the event Ball conducted at Goddard Space Flight Center, Corp., and STScI in Technologies Aerospace and order to ascertain the most likely cause and to devel- op a recovery strategy. that a fuse in the power line feeding STIS has blown, and currently the most likely explanation of that would be a short circuit in STIS, which was not Attempts have been actively observing at the time. made to cycle a power relay between the fuse and STIS, which failed to restore power to STIS, elimi- nating the low-probability chance that the relay could have been inadvertently opened. Fortunately STIS has a fully independent side of electronics (hereafter referred to as side 2) to operate the instrument. Reviews are underway to define the areas within flight software, commanding, databases, testing and it does keep finding ways to keep those of us on the it does keep finding working to keep it running ground on our toes and year has seen The past and efficiently. effectively several such episodes. properly when commanded to shutter did not open intermittent, starting with a The problem was do so. and increasing slowly over August few glitches in effort An intensive analysis the next several months. at STScI, GSFC, and JPLby staff determined that a timing the likely cause was the slow eroding of WFPC2 microprocessor as components in the margin aged in the radiation environment of Hubble A flight software patch in November restored the and since then we have had no timing margins, WFPC2 further problems. In fact, this spring the achieved the milestone of its 100,000 exposure (averaging 40 per day if my math is correct).

T H Newsletter Newsletter 18

INSTRUMENT NEWS • Space Telescope Science Institute Science Telescope Space web site, tion atthecenterofCCD. losses relativetospectratakeninthedefaultloca- vide afactoroffivedecreaseinCTE-relatedcharge readout amplifier. This capabilityisexpectedtopro- spectra withthetarget positionedmuchnearerthe full implementationofthecapabilitytoacquire will beaddressedforspectroscopyinCycle11 with monitoring.SpeakingofCTEissues, these MAMA tion STIS/CCDmonitoringandwiththeNUV- discrepancies withthehighercountlevel,low-resolu- CTE-relatedcharge lossesthatfullyexplainthe to associated withthemedium-resolutionspectralead CCD, itisnowrecognizedthatthelowcountlevels est Charge Transfer Efficiency trendingfortheSTIS CCD gratingmodes.Followingavailabilityofthelat- (~1% peryear)declineinsensitivitythantheother ing modehadinrecentyearsshownaslightlylarger STIS CCDgrat- MAMA. The medium-resolutionUV STIS CCDandequivalentgratingsfortheNUV- gratingsforthe the medium-andlow-dispersionUV been resolvedbetweenderivedsensitivitytrendsfor minor butlong-standingdiscrepancyhasrecently gram alreadyunderway. WFPC2 ifthiswouldsavethescienceforapro- cases thismightmeanswitchingSTISimagingto tain highscienceproductivityfromHST. Insome attempt torespondindividuals interruption inSTISobserving,andSTScIwill observingcommunityhasbeennotifiedofthis HST efficiency canbemaintainedatahighlevel. The of SNAPshottargets, itisexpectedthatobserving Spectrographs Further informationaboutSTIScanbefoundatour In theareaofon-goingcalibrationactivities,a http://www.stsci.edu/instruments/stis/. from page17 Paul Goudfrooij,replacingJerryKriss,whohasmovedtotheNGST Division centers ofnearbyellipticalgalaxies andtheUVextinctionpropertiesofdust to workonthedefinitionanddevelopmentofscienceinstruments. Paul research tostudytheexcitation mechanism ofemission-lineregionsinthe has beenintheSTISgroupsince1996,andoverseencalibration program forthepasttwoyears.Hisresearchinterestscenteron elliptical The STISinstrumentgroupatSTScIisnowunderthenewleadership of galaxies andextragalacticglobularclusters.HeisusingSTISin hisown ’ needs andmain- lanes inellipticalgalaxies. Goudfrooij Named STIS Lead STIS Named Goudfrooij Ed Nelan, Fine GuidanceSensors R performance evenwithoutthiscalibration. unique opportunitytoevaluateFGS1r of GOproposal9167(PIBenedict)provideda ment tion ofthegeo astrometer able tofullyassessitscapabilityasawide-angle ence instru FGS1r. say, correctionstothesevalues areintheworks.) involved intrackingthestellarfringes.Needlessto the valuesassignedtoengineeringparametersthatare isrelatedto Y-axis. (Thedifference alongXand Y FGS1r X-axisandbylessthan1.1masalongthe by lessthan0.7milli-secondsofarc(mas)alongthe geometric distortioncalibration.) constant andthedatacouldbecombinedwithout and pointingwereheldconstant,thedistortionwas to thataverage.(Becausethetelescope averaged andthedatafromeachorbitwerecompared be determinedwhenseveralorbitsworthof measured. The accuracyofthesemeasurementscould ofthestarsrelativetooneanotherwereprecisely tions scope rollangleandpointing.Ineachorbittheposi- orbits,allatthesametele- for fiveconsecutiveHST and 5referencestarswereobservedinPositionmode For Benedicts The differences instarpositionswerefoundtovary ’ s fieldofview. Observationsmadeonbehalf Although FGS1rhasbeeninuseasasci- astrometric performancetobeexpectedfrom (GO) programhaveprovidedinsightintothe ecent observationsfromaGeneralObserver [email protected] because welackedthecriticalcalibra- ment sinceCycle8,wehavenotbeen metric distortionsacrosstheinstru- ’ s program,thestarEpsilonEridani continued page 19 ’ ’ s orientation s astrometric data were Summer 2001

FGS from page 18 cosmic ray flux that accompanies each solar maxi- mum. Cosmic rays produce luminescence in the These experimental results are most impressive when CCD windows, and this glow accounts for much of one considers the range in brightness of the stars that the observed dark current. We anticipate the dark were observed. At V = 3.7, Epsilon Eridani is near the current will go back to its old rate of increase once bright limit for FGS1r, while the reference stars solar maximum has passed. ranged in brightness from V = 15.6 to 16.8, i.e., near The Cycle 9 calibration program is now nearing the FGS1r faint limit. Interestingly, we see no relation completion. Most monitor observations from previous between a star’s brightness and the accuracy with cycles were continued. New calibrations included an which FGS1r measured its position: FGS1r achieves absolute calibration of CTE utilizing a series of ~1 mas per orbit astrometric precision over its full faint standards that are also being observed from dynamic range. This suggests that multi-epoch the ground. We also conducted wavelength stability observing programs should obtain parallaxes accu- checks on the narrow-band and ramp filters, as well rate to 0.3 mas even for stars as faint as V=16.8. as measurements of redleak for the UV filters. The As noted in the previous STScI Newsletter, the Cycle 10 calibration plan is currently being formulated, data for calibrating the FGS1r geometric distortion and will be similar to those in previous cycles. There were obtained in December 2000. The analysis of will also be additional studies of CTE effects on these data is currently underway at the University of extended targets, source morphology, and astrometry, Texas at Austin. Preliminary results indicate that the as well as calibrations of the PSF wings. Observers calibration will be very successful. STScI anticipates are welcomed to suggest areas where additional the final calibration to be available by mid-summer, calibrations are needed. They should be mindful that at which time the FGS1r calibration pipeline will be all calibrations must be completed before the instru- updated, and all wide angle (Position mode) astrometry ment is de-orbited in a few years. data obtained with FGS1r (and held in abeyance since Version 6.0 of the WFPC2 Instrument Handbook INSTRUMENT NEWS cycle 8) can finally be fully reduced and analyzed. will be released shortly. Changes from the previous Further information about the FGSs can be found version are minor, and mostly concern CTE, dithering at our web site, http://www.stsci.edu/instruments/fgs/. strategies, and the calibration programs. The Handbook, along with other reports mentioned above, are available at the WFPC2 web site, WFPC2 http://www.stsci.edu/instruments/wfpc2/. John Biretta, [email protected]

FPC2 has passed the 100,000-image mark and continues to perform well. WWe have not seen any new incidents of the shutter anomaly; the on-board software patch appears to have mended the problem. A recent study of the shutter’s long-term stability has revealed a marked increase in its mechanical jitter starting early last year. This has no direct impact on observations, but does underscore the presence of mechanical wear, and may have contributed to the anomaly seen last fall. A recent study of the dark current shows that the long-term increase was interrupted in early 1999, and the dark current has been nearly constant since then. (See Fig. 1.) This effect is seen in all four cameras as well as in the STIS CCD camera. We Fig. 1. Dark current evolution in WFPC2 PC1 CCD from believe this is attributable to a reduction in the 1994 to 2001.

19 Newsletter Newsletter 20

INSTRUMENT NEWS • Space Telescope Science Institute Science Telescope Space N Torsten Boeker, Petro, Larry EddieBergeron Daniela Calzetti, NICMOS given intheMarch2001STScI Newsletter. summaryof exposures below~1.7micron. A loss inlimitingmagnitudeof~0.3magforlong 7 and7Nisexpectedtobesmall,withaworst-case decrease inoverallperformancerelativetoCycles compensates fortheincreaseddarkcurrent. The impacts areexpectedtobe: 15-25 Khigherthanwiththenitrogencoolant.Themajor The operatingtemperatureofNCS/NICMOSwillbeafull be around86K. in darkcurrent(lessorabout2e-/s)isexpectedto be considered.For T>80K, indeed,theminimum the possibilityofoperatingNICMOSat~86Kwill present (seetheMarch2001STScINewsletter), er than,80Kandifthedarkcurrentexcessis able temperatureatthedetectorsisabout,orhigh- within theNICMOScryostat.Ifcoolestachiev- ing externalradiators,andthethermalgradient NCS, thetemperatureattainedbyheat-reject- asitic heatloadsontheNICMOSdewarand NCS on-orbitperformance,theamountofpar- ture dependsonanumberoffactors:theactual with abestestimateof78.5K. This tempera- K, detectors toatemperatureintherange75-82 beginning of2002. Mission 3B,whichiscurrentlyscheduledforthe cooling system(theNCS)duringServicing The instrumentwillbereactivatedwithanactive January 3,1999,whenthenitrogenwasdepleted. coolant. The instrumenthasbeeninactivesince (Cycles 7and7N),usingsolidnitrogeniceasa cessfully fromFebruary1997toJanuary1999 currently onboardHST. NICMOSoperatedsuc- In termsofsensitivity, thehigherDQEpartially 2 1 The NCSisexpectedtocooltheNICMOS . An increaseintheDQE,by~40-65%at1.1 . An increaseinthedarkcurrent,from<0.05e-/s at 2.2micron. micron, ~30-50%at1.6and20-25% e-/s (iftheexcessisnotpresent). to ~2.0e-/s(iftheexcessispresent)or~0.5 instrument andtheonlyinfraredcapability Multi-Object Spectrometer, isacryogenic ICMOS, theNear-Infrared Cameraand [email protected] T latest newscanbefoundontheNICMOSwebsite, rium.edu/origins/hubble/index.html) ing as NCS/NICMOS arebeingprepared. for supportingtheOn-Orbit Verification ofthe used intheExposure Time Calculator;andproposals tion ontheexpectedNCSperformancehavebeen the Cycle11 CallforProposals;thenewestinforma- NICMOS InstrumentHandbookwillbereleasedwith operations withNICMOS:anupdatedversionofthe webcast bytheExploratorium. patibility testing. The latteractivitieswererecently for itsfinalthermalvacuumtestandelectricalcom- ground calibrationtest, ACS wasshippedtoGSFC become available.Followingtheconclusionof be publishedasupdatesonthe ACS webpageasthey Handbook update. The majorityofinformationwill early resultswillbeincludedintheInstrument of thegroundcalibrationdataisunderwayandsome lower thanthepreviouslypublishedfigures. Analysis performanceis tor hasbeenchangedandthenear-UV figures, however, theHighResolutionChanneldetec- Channel isverysimilartothepreviouslypublished formance forthe Wide FieldChannelandSolarBlind Simulator atBall Aerospace. The instrumentper- while itwasmountedintheRefractive Aberration two weekswerespentcalibratingtheinstrument have beeninstalledandoptimized.InMarch2001, Clampin, Mark Advanced CameraforSurveys http://www.stsci.edu/instruments/nicmos/. http://www.stsci.edu/instruments/acs/. group willpostupdatesonthe mission, andCycle11 becomeavailable,the ACS moreinformation ontheinstrument,servicing as 11 CallforProposals.Duringthecomingmonths Handbook, whichwillbeissuedwiththeCycle is summarizedinanupdated ACS Instrument Cycle 11. The currentperformanceoftheinstrument a January2002launch. The ACS willbeoffered in The revivedNICMOSpromisestobeasexcit- Work isprogressingtosupportaneweraofscience Servicing Mission3Biscurrentlyscheduledfor the Mission 3B.Eachofthethreeflightdetectors fully he Advanced CameraforSurveysisnow ‘ old integrated inpreparationforServicing ’ NICMOS. Updatedexpectationsand [email protected] (http://www.explorat ’ s website, 21

INSTRUMENT NEWS Summer 2001 with the ” All About Low, “ “ or ” A can be raised to target ” Medium, “

Priorities may be changed at ” ” Medium. “ High, Low. “ “ If you have ideas for new ways in which ” only if another in the same program is send a message. ” twice during the Cycle. targets in Cycle 1. targets SNAPs on the sky Information on the duration of typical SNAP visits Details on the procedures for scheduling SNAPs distribution of requested and executed The New rules for specifying priorities for SNAP New rules for specifying ¥ ¥ ¥ ¥ Starting in Cycle 11, SNAPStarting in Cycle 11, priorities can be Of course we concentrate our effort in scheduling our effort Of course we concentrate a fresh look to see if Recently we gave SNAPs Also, starting in Cycle 11 observers may use the Also, starting in Cycle 11 For more information, please see High All About SNAPs includes: specified as default being “ from which we draw to fill in schedule gaps. from which we draw of the ordinarily manage to get 50% or more We SNAP for most requested targets programs. GO programs, treating observations on regular SNAPSNAPs as a second priority. visits must be Phase 2 program is submitted, fully defined when the and as short as and they should be constraint-free repeat SNAP do not We possible. visits if they fail. we loosen some of those constraints without could realized also We adding work in implementing them. of what that proposers might not have a good idea this gap, fill To succeeds as a SNAP. most to special requirement BETWEEN on SNAPs constrain an observation to fall within a one-week there is no As with any SNAP, calendar period. but using guarantee that an observation will occur, BETWEEN makes it possible to create monitoring images at random intervals. say, programs that gather, SNAPs. SNAPs could be made more useful for science, please bumped to http://presto. , is available at [email protected] s Associate Administrator for Space ’

s Call for Proposals for Cycle 2 introduced he Hubble Operations Division has taken he Hubble Operations observing in steps to enhance SNAPshot we want to explain and adver- and Cycle 11, ’

All About SNAPs schedule would be filled with GO observations, schedule would be filled SNAPs have an interesting history. The basic SNAPs have an interesting history. SNAPshot observations fill the gaps in the HST SNAPshot observations HST These days we accept 1,000 or more SNAP targets The SNAP for observer specifies a list of targets with no wasted time. In reality, the various with no wasted time. In reality, constraints placed on GO observations give rise to blank odds and ends of HST time, which creates the SNAP opportunity. Weiler, concept should probably be credited to Ed currently NASA observing schedule that inevitably appear when we observing schedule that (GO) programs. Ideally, plan General Observer the stsci.edu/uir/uir.html. tise the opportunity for SNAPtise the opportunity for to the observations A community. User Information Report, enti- new tled Science, who recognized the value of unused bits of Science, who recognized the value of unused at telescope time on Copernicus when he worked gaps Princeton in the late 1970s. He used these to late-type stars in the ultraviolet. Shortly survey after HST was launched, John Bahcall discussed Rodger similar kinds of quick, filler observations with of Doxsey and Riccardo Giacconi, then Director The first SNAPSTScI. program took images to look for lensing around quasars. SNAPshot surveys to the astronomical community. images At that time they were foreseen to be strictly gyro lasting no more than 2 to 6 minutes and under control (i.e., not using the FGSs for pointing). per cycle, and each SNAP can be as long as 30 minutes or more. SNAPs can obtain images or spectra, and there have even been SNAP programs for moving targets! which data on only a subset can still yield useful create a master list of all SNAPscience.We targets,

All about SNAPs All about Soderblom, David T Newsletter • Space Telescope Science Institute

Updated Guide Star Catalog Now Available Brian McLean, [email protected]

he Catalogs and Surveys rate coordinates, magnitudes and clas- catalog. The only proper motions pro- Branch (CASB) of the Space sifications for all objects. A database vided are those from the Tycho-2 cata- TTelescope Science Institute has called COMPASS was constructed log. It must be emphasized that this been digitizing the photographic sky to hold the GSC II data using interim release should not be used survey plates from the Palomar and Objectivity, a commercial Object- for HST guide star coordinates at UK Schmidt telescopes to produce Oriented database system. The astro- this time. The final version of the new versions of the Guide Star metric reference catalogs are the ACT catalog (GSC 2.3) with all detected Catalog (GSC II) and Digital Sky and TYCHO2, and photometry will be objects, proper motions and the Survey (DSS II). These catalogs sup- based upon CCD sequences obtained near-IR magnitudes will be available port ground- and space-based telescope for each plate. This project is expected in the summer of 2002. operations and provide a valuable sci- to be completed in 2002. The GSC II consortium is dedicat- entific resource to the astronomical With more than 998 million unique ing the catalog to the memory of Dr. community. Fig. 1 illustrates the objects in the database thus far, con- Barry M. Lasker, who passed away second-generation improvements. struction of the complete GSC II is in February 1999. Dr. Lasker, one The CASB group at STScI and the still in progress. The GSC 2.2 is an of the founders of the STScI, was Astrometry Group of the Osservatorio all-sky, magnitude-selected subset of directly responsible for the vision Astronomico di Torino, in collabora- the complete catalog designed to sup- that led to the creation of the DSS tion with the Astrophysics division of port Telescope Operations. It contains and GSC projects that have greatly ESA, the GEMINI project, and the the positions, classifications, and magni- influenced and benefited modern Space Telescope European tudes for 435,457,355 objects, and is observational astronomy. Coordinating Facility (ST-ECF) have now available to the community via The Guide Star Catalog II is a joint been working together on GSC II. It is the WWW through the MAST inter- project of the Space Telescope Science an all-sky catalog based on processing face, http://archive.stsci.edu. Institute and the Osservatorio Astro- the photographic Sky Survey plates, at This preliminary catalog contains nomico di Torino, whose participation two epochs and three bandpasses (F, J, positions, classifications and at least has been supported by the Italian IV-N), from the Palomar and UK 2 magnitudes for all object brighter Council for Research in Astronomy. Schmidt telescopes. than 18.5 in photographic F and 19.5 Additional support was provided by the GSC II will use multiple epochs in photographic J. Since bright objects European Southern Observatory, the ST- and bandpasses of the survey plates are heavily overexposed on Schmidt ECF, the International Gemini project, in order to obtain proper motion and plates, we have replaced the bright and the European Space Agency color information in addition to accu- stars with those from the Tycho-2 Astrophysics Division.

Fig. 1. Illustrations of the improve- ments in the second-generation Guide Star Catalogue (GSC II) and Digital Sky Survey (DSS II). Top: the Rosette Nebula, (originally pho- tographed by the Palomar Observatory) as digitized in the DSS I (left) and DSS II (right). The DSS II includes views of the sky at both red and blue wavelengths, providing color information on about one bil- lion deep-sky objects. Bottom: blow- up of the inset box showing the GSC I and the improved GSC II catalogs, which provides the colors, positions, and luminosities of nearly half a bil- lion stars as dim as the 19th magni- tude—over 20 times as many as the original GSC I.

22 Summer 2001

New IT Services at STScI Bob Hanisch, [email protected]

he Computing and Information ance”. Our new Mirapoint e-mail server organization, consistency of look-and- Services Division installs and is optimized for large-scale e-mail deliv- feel across STScI web sites, and better Tsupports all Institute computing ery and storage. Because it is an IMAP- integration between design and function. and networking facilities and maintains compliant server, it allows STScI staff The Future of Unix the infrastructure of the Institute’s to have complete access to e-mail with a An interdivisional study group is tak- information systems. Our current initia- variety of clients from both on- and off- ing a comprehensive look at the current tives include the following projects. site. The new Mirapoint system will also uses and future needs for Unix systems simplify system administration and at the Institute. Originally, the purpose Help Desk improve reliability of service, as it replaces An internal process improvement of this study was to evaluate total costs a hybrid system of nearly 20 mail servers. study conducted last summer led us and develop implementation strategies to restructure our user support proce- www.stsci.edu for the more widespread use of Linux. dures, with the most visible change The Institute’s web site was designed The study group quickly realized that being the creation of a new “Help more than four years ago, and both the Linux is just one of a number of pos- Desk” with dedicated staff now pro- amount and the complexity of the sible options. Considerable interest viding all day-to-day, front-line sup- information available through the site has developed in the new Mac OS X, port. After six months of operations, has increased dramatically. Last year we which has at its core the Mach kernel. the Help Desk staff is handling over began a systematic program to upgrade Staff and visitors have expressed 40% of all user questions and prob- our web site and the information man- some frustration that STScI does not lem reports. Staff and visitors at agement structure behind it. We adopted already provide general support for STScI can contact the Help Desk by a web management software package Linux. However, with an installed base phone (x4400), e-mail (cisdsupport called Zope (which is based on Python) of some 350 Sun Solaris systems, the @stsci.edu), the web (http://cisd. to support the information architecture, associated layered software, and limited stsci.edu/support/), or in person and embarked on a program of site system administration resources, we do (Room 331, 8:00am-4:30pm M-F). redesign. From an internal perspective, not intend to incorporate Linux systems the new framework will make it much into our environment until we fully New E-Mail easier to capture and provide informa- understand the cost impacts. Less Architecture and Server tion, and make it unnecessary for any- expensive hardware does not always Following a study by an e-mail one to have to hand-edit HTML. assure lower cost overall. The recom- technology evaluation team, we decid- Visitors to the STScI web site will soon mendations of the study group and a ed to centralize e-mail services for see elements of this new framework, management decision on Unix futures STScI staff using an “e-mail appli- including simplified navigation, better should come out this summer.

Calendar

Cycle 11 The Space Telescope — Call for Proposals issued June, 2001 European Coordinating Facility publishes a quarterly newsletter which, although aimed principally at Phase 1 proposals due September 7, 2001 European Space Telescope users, contains articles 8:00 PM EDT of general interest to the HST community. If you wish to be included in the mailing list, please Proposers notified December, 2001 contact the editor and state your affiliation and Phase 2 Proposals Due February, 2002 specific involvement in the Space Telescope Project. Budgets Due February, 2002 Robert Fosbury (Editor) Space Telescope — Routine Observing Begins July, 2002 European Coordinating Facility Karl Schwarzschild Str. 2 Space Telescope Users Committee October 25-26, 2001 D-85748 Garching bei München Federal Republic of Germany Servicing Mission 3B Launch January, 2002 E-Mail: [email protected] 23 Contents Contact: The Institute’s website is: http://www.stsci.edu New Proposal Opportunities in Cycle 11 ...... 1 Assistance is available at [email protected] or 800-544-8125. Director’s Perspective ...... 2 International callers can use 1-410-338-1082. The ACS High-Latitude Survey Workshop ...... 3 An Interview with Bruce Margon ...... 5 For current HST users, program information is available at: http://presto.stsci.edu/public/propinfo.html. First Spring Symposium Webcast ...... 6 Cosmology’s Heart of Darkness ...... 7 The current members of the Space Telescope Users Committee Hot Summer for a Cool Telescope ...... 8 (STUC) are: The Day Superman Saved ST ...... 9 George Miley (chair), Sterrewacht Leiden, Future AO for NGST Science Investigations ...... 11 [email protected] Big Improvements at the MAST Web Site ...... 12 Marc Davis, U.C. Berkeley Measuring Hubble’s Science Impact ...... 14 James Dunlop, Royal Obs. Edinburgh Hubble Fellowship Program ...... 16 Debbie Elmegreen, Vassar College Holland Ford, JHU Hubble Postdoctoral Fellowship Program ...... 16 Suzanne Hawley, U. Washington Updated Guide Star Catalog Now Available ...... 22 Chris Impey, U. Arizona New IT Services at STScI ...... 23 John Kormendy, U. Texas, Austin Dave Sanders, U. Hawaii Karl Stapelfeldt, JPL Instrument News John Stocke, U. Colorado Hubble Status & Prospectus ...... 17 André Vidal-Madjar, CNRS, Paris Spectrographs ...... 17 The Space Telescope Science Institute Newsletter is edited Fine Guidance Sensors (FGS) ...... 18 by Robert Brown, [email protected], who invites comments and WFPC2 ...... 19 suggestions. Near-Infrared Camera Technical Lead: Christian Lallo and Multi-Object Spectrometer (NICMOS) ...... 20 Design: John Godfrey Advanced Camera for Surveys (ACS) ...... 20 Layout: Christine Klicka Production Assistance: Pat Momberger All About SNAPs ...... 21 To record a change of address or to request receipt of the Calendar ...... 23 Newsletter, please contact Ms. Nancy Fulton ([email protected]). How to contact us ...... 24

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