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January 1998

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Volume 15, Number 1

SPACE TE LESCOPE SCIENCE INSTITUTE
Highlights of this issue:

Newsletter
Cycle 7-NICMOS Proposal Augmentation
Brett S. Blacker and C. Megan Urry, STScI blacker@stsci.edu, cmu@stsci.edu

· Cycle 7-NICMOS Accepted Programs
-- page 16

· Report of the Independent Science Review
-- page 22

· STScI Mourns Chris Skinner
-- page 3

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s you probably know by now, NICMOS is anticipated to have a useful lifetime of about 1.6 years, ~1/3 of the lifetime expected prior to launch. An Independent Science Review (ISR) committee met in May, 1997, to develop recommendations on the appropriate response to the shortened lifetime (see page 22). From their recommendations, STScI proceeded with a plan which will allow us to recover most of the anticipated observing time: · Increase the allocation of observing time for NICMOS to between 40 and 50% of the total HST observing time through December 1998, the assumed end of useful NICMOS observations. · Issue a special Call for NICMOS proposals to augment the current Cycle 7 program. · Allow for at least limited NICMOS Camera 3 use, via special observing campaigns if necessary. To meet the recommendations of the ISR and to have ~10% of the new Cycle 7-NICMOS programs available for scheduling in January of 1998, a highly compressed proposal review schedule was developed. The Cycle 7NICMOS Call for Proposals was issued on July 9, 1997; the Phase I deadline was September 5, 1997; the review panels and the TAC met the week of October 5 - 10, 1997; and the Phase I notifications occurred on October 23, 1997. To meet this ambitious schedule and to continue our Phase I process improvement, several changes were implemented, including:

· The notification for the Call for Proposals was issued by postcard and email, with the documentation was posted on the STScI Web pages. Hardcopies were mailed to libraries and institutions only, to others it was available upon request. · Proposers were required to submit their proposals electronically; no paper copies were accepted. In the preceding review, ~80% of the programs were submitted in this fully electronic fashion. · In place of the traditional written feedback to proposers, we provided a Comments Table based directly on the selection criteria described in the Call for Proposals. This simple Table, which is similar to those used in some other NASA reviews, focused the panelists on the key issues, provided uniform feedback across all panels, and reduced the level of effort by panelists and STScI staff, thus shortening the notification time by several weeks. 449 proposals were submitted for review, with requests for 6473 orbits from 415 GO proposals, and for 3065 targets from 34 SNAP proposals. For comparison, in Cycle 7 (September 1996), 388 NICMOS proposals were submitted for review, with requests totaling 7735 orbits from 362 GO proposals and 3345 targets from 26 SNAP proposals. In the present Cycle 7-NICMOS, proposals were received from 17 countries and from 31 states as well as the District of Columbia and Puerto Rico. 121 GO proposals totaling 1873 orbits were submitted by

ESA Members as well as 5 SNAPshot proposals for 340 targets. Following the review, 75 GO proposals were awarded a total of 1041 orbits and 8 SNAPshot programs were given 473 targets. The approved programs are listed on page 16 in this Newsletter as well as posted on the "Observing with HST" Web page located at:
http://www.stsci.edu/observing/ observing.html.

The Abstract and Exposure Catalogs for the approved Phase I proposals can be found on the "Proposing with HST" web page located at:
http://www.stsci.edu/observing/ proposing.html.

As noted above, the Cycle 7NICMOS Panels and TAC met during the week of October 5 - 10, at STScI. The 49 members who reviewed the proposals among the seven subdisciplinary panels, as well as the TAC chair, Anneila Sargent of the California Institute of Technology, and the five TAC at-large members, are listed elsewhere in this Newsletter. All of us owe these scientists enormous gratitude for participating in this review and for recommending the Cycle 7-NICMOS Augmentation Program to the STScI Director. The Science Program Selection Office is always interested in hearing from the communTMity on ways to improve the process. If you have any thoughts or comments that you would like to share, please send them to spso@stsci.edu.


Newsletter

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Space Telescope Science Institute

Director's Perspective
Bob Williams

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he special TAC has now met and recommended the allocation of time for supplemental NICMOS programs for execution in Cycle 7 before the cryogen is depleted, amounting to 1,041 additional orbits. At the same time, the Servicing Mission Observatory Verification has also been completed, and the new instruments are now enabled for a broad range of different observing modes. The Institute is working hard on the implementation of Cycles 6 and 7 programs, and recent weekly schedules have shown NICMOS observations taking up over 50% of the available time, and STIS being scheduled more than 25% of the time, so we are already close to achieving the recommendations of the Independent Science Review in this regard. The HST data archive is growing rapidly with STIS and NICMOS data.

Two important events have taken place related to the long-range future of HST. First, the ultraviolet Cosmic Origins Spectrograph (COS), with Dr. James Green of the University of Colorado as PI, has been selected as the major new instrument to be installed in HST on the 2002 servicing mission, the final planned mission to service the telescope. Second, the Project has been successful in obtaining NASA acceptance of a long-range planning budget which provides for cheaper (<25% of current costs) operations of HST until the year 2010, i.e., five years past its previous nominal end of mission date. The Institute is collaborating with the Project on a study of how HST might be operated inexpensively in the era when the servicing missions are not the cost drivers that they are presently. Extended operation of HST for a period of eight years without a servicing mission offers opportunities and it imposes certain constraints which are important to understand. The Project is therefore requesting a study of `HST's Second Decade' which the Institute will be conducting and which will address these issues with community input and involvement. The details of the study are yet to be worked out and will be essential input for the formulation of HST operations and the science program after the last servicing mission and at a time when NGST and other Origins mission may also be operational.

HST Recent Release: M2-9 Planetary Nebula

M2-9 is a bipolar planetary nebula 2,100 light-years away in the constellation Ophiucus. This WFPC2 observation was made August 2, 1997. Credits: Bruce Balick (University of Washington), Vincent Icke (Leiden University, The Netherlands), Garrelt Mellema (Stockholm University), and NASA

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January 1998

Christopher J. Skinner

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riends and colleagues of Dr. Chris Skinner were shocked and saddened by his sudden death on October 21st 1997, while he was visiting his parents home in Norfolk from his base at the Space Telescope Science Institute. His death at the tragically early age of 34 has cut short an outstanding career in astrophysics. Chris had been recently appointed to a Lectureship in Astrophysics in the University of Sheffield's Department of Physics and was due to take this appointment up in January 1998. Chris had been a diabetic since the age of two and it appears that it was a sudden worsening of this condition which caused his death. Following his education in King's Lynn, Norfolk, Chris Skinner undertook a BSc Honors Degree in Physics and Astronomy at University College London (UCL), graduating in 1984. He then stayed at UCL in order to undertake a PhD research project with the infrared astronomy group. There he Chris Skinner in a typical pose with a established his instrumentation skills typical t-shirt from his collection. We and at the same time independently shall remember him this way. embarked on a separate collaborative project to analyze and model the At the end of 1994 he took up his infrared spectra of cool star dust shells position as an ESA staff member here that had been obtained by the IRAS at the Space Telescope Science astronomical satellite. He quickly Institute, where he was part of the team revealed himself to be a talented responsible for the successful theoretician and programmer. This commissioning of the infrared camera unique combination of expertise in both instrumentation and in theoretical modelling was to feature strongly in Christopher J. Skinner his subsequent successful June 26, 1963 -- October 21, 1997. career as a professional astronomer. Following his PhD in Astrophysics in 1987 and a subsequent NICMOS, which was installed on the postdoctoral appointment at UCL, Hubble Space Telescope by Shuttle Chris won an SERC personal Research astronauts in February of 1997. Fellowship, which he elected to hold at Chris worked very long hours to Jodrell Bank in 1990 and 1991. There characterize the properties of he embarked in an energetic program NICMOS, helping to make it the that made use of the MERLIN radio success it has become, and contributed interferometer. In addition, he essential intellectual input to underdemonstrated how useful the Jodrell standing the instrument. In his time at two-element Broad-Band radio STScI, Chris developed strong bonds Interferometer (BBI) could be. At the with the others working around him, end of 1991, Chris moved to a position and his loss is felt at a deep personal

at the Lawrence Livermore Laboratory in northern California, where he stayed for three years. There he was responsible for operating and upgrading the Berkcam 10-micron infrared camera. At the same time he initiated many successful new observing programmes which made use of this instrument on the telescopes on Mauna Kea, Hawaii.

level as well as professionally throughout the Institute. All through his professional career Chris was prolific in publishing scientific papers. These covered a large range of topics, and included infrared, optical and radio observations, as well as theoretical radiative transfer modelling of molecular lines and dust emission continua. As a result Chris has made an enduring contribution to our understanding of dust discs around main sequence stars; mass loss; molecules and dust in outflows from evolved stars; and the origin of planetary nebulae. A paper on the bipolar Cygnus Egg Nebula which he first-authored, and which appeared in the journal Astronomy and Astrophysics after his death, is representative of his strengths and creative abilities, gathering a wide range of new observational data to which he applied sophisticated axisymmetric radiative transfer modelling and great physical insight to achieve an elegant new synthesis for understanding this complex system. Chris had a brilliant career in astronomy ahead of him. His untimely death is a major loss to astronomy. However, his loss is a deeper one for those who knew him personally. He always seemed to view life with amusement and certainly lived it to the full. His sense of the surreal was always evident -- for instance, Uncle Billy's bar in Hilo was always his favorite place to repair after an observing run on Mauna Kea. Chris's interest in people and in life was also evident in the many and detailed emails that he sent to his friends and colleagues -- he must have typed millions of words into this medium over the years. It is difficult to come to terms with Chris's sudden loss.

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Newsletter · Space Telescope ScienceNewslette r Space Telescope Science Institute · Institute

An Amazing Summer
The OPO Amazing Space team

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he Office of Public Outreach conducted its second annual Amazing Space workshop this summer, and it was indeed an amazing experience for all of us involved in the project. The Amazing Space workshop is a five-week program whose goal is to produce five online (K to 12) lesson/ activities that teach fundamental scientific concepts using HST data to illustrate them. These lessons are intended for classroom use; therefore the topics need to fit in with the subject matter that teachers normally present to their students. We want to provide what teachers need, want, and will use. Hence, the lesson topics we choose for the workshop address National Standards and Benchmarks (guidelines that schools follow to teach certain skills and topics in certain grades). Another important program element is providing teachers with the experience of working at a scientific institute, giving them direct contact with research scientists, and exposing them to cutting edge science. As part of this experience, five staff scientists gave talks on recent science developments.

We selected 10 teachers (two elementary school, four middle school, and four high school) for the workshop from an impressive pool of applicants. Our 10 teachers came from Baltimore City, five Maryland counties, and one Virginia county. They were selected based on their curriculum development and team and World Wide Web experience.

All For One
Through experience, we discovered that successful lesson design requires a team of experts from several disciplines. Each team consisted of two teachers, a Web programmer, a graphic artist, a science advisor from the scientific staff, and a member of OPO who acted as facilitator and general resource. The teachers offered their experience in formulating lesson ideas based on their background in pedagogical principles. The scientists provided their expertise, thus guaranteeing scientific accuracy. The graphic artists and the Web programmers provided their knowledge of page layout, Web resource creation, and the

use of appropriate colors, designs, and computer technology. It was an enlightening process to watch people from diverse backgrounds add their expertise to create one uniform science lesson. Research indicates that a good lesson must be interactive and use real data in order for it to work in the classroom. An effective classroom lesson must be modular so that a harried teacher can pick part of it to use. The activity also must fit the established curriculum and conform to education standards which the teachers must meet. We use a creative process that incorporates these characteristics into our lesson/activities.

Evaluation -- A Critical Part of Our Process
Since the end of the workshop, we in OPO have been working to complete the programming and graphics for the lessons. Once completed, the lessons will go through a rigorous review by a panel consisting of a scientist and teachers, as well as members of OPO's lesson evaluation
continued page 5

A Quick Tour of the Lessons
The path each team took was truly unique. Here is a brief description of each lesson.

Comets, Gravity, Action!
elementary school
This activity teaches the relationship of mass and gravity. To learn the principles of escape velocity, students toss projectiles into orbit to compare the gravitational fields of the Earth, a comet, and Jupiter. Another module has the students build a virtual comet by selecting ingredients such as ammonia, dirt, methane, water, and sodium. The ingredients will determine what the comet will look like. Some comets, for example, will have an ion tail; others won't.

Star Light, Star Bright
middle school
Light is broken down into its components, both visible and invisible. A lesson highlight is the module that shows students how to look at a star and tell something about its physical characteristics - just like a scientist does. The module explores the relationship between color and temperature. Students, for example, toast a robot and observe how its color changes. They also apply the information they learned about color and temperature to real images of clusters of stars observed by the HST.

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January 1998

Amazing Summer

from page 4

The 1997 Amazing Space Scientists
Alex Storrs
Comets, Gravity, Action!

team. The lessons are reviewed for scientific accuracy, appropriate pedagogical principles, and Web design. After the initial panel review, the lessons will be pilot-tested in local classrooms, revised as necessary, and then released on the Web. Once the lessons are released, OPO will continue to collect evaluation data via the Web as well as through local classroom observations. We estimate that all of the lessons should be on the Web site by the end of November.

Karen Schaefer
Planetary Nebulae

Anuradha Koratkar
Stars Light, Stars Bright

Dan Steinberg
No Escape: The Truth About Black Holes

Jeff Hayes & Terry Teays
How Far is Far? Determining Really Humongous Distances
If you'd like to get involved with the 1998 Amazing Space Workshop as a science advisor, please let us know.

New Evaluation Prospects
In addition to the standard evaluation program, OPO and the University of Chicago are discussing a possible collaboration to study the long-term effects of using the Web as a teaching and learning tool. The discussions have included the possibility of using the Amazing Space lessons as part of the content provided to the teachers and students who will participate in this study. The goal of this study is to learn more about the impact of technology in the classroom and how to best design Web-based science lessons to meet the needs of teachers and students.

Join the Team
You too can get involved in education! If your Web site contains information related to one of our Amazing Space lessons, provide a link to that lesson. If you are in contact with teachers through public talks, IDEAS grants, or in any other way, let them know about the Amazing Space Web site. When the lessons are posted on the Web site, please try them and let us know what you think.

Visit the "Amazing Space" Web site located at: http://www.stsci.edu/pubinfo/amazing-space.html Send your questions and/or comments to: amazing-space@stsci.edu

Death of the Red Giants: Planetary Nebulae
middle school
This lesson uses exquisite HST images of planetary nebulae as a tool to build basic skills addressed in middle school, such as sorting and organizing. Module activities include: sorting various types of nebulae by physical characteristics, arranging them in an evolutionary sequence, and coming up with names for the strange-looking nebulae. Some of the names they suggest will be posted in the lesson, along with the names of the students and their schools.

How Far is Far? Measuring Really Humongous Distances
high school
This activity is designed for astronomy and math classes. Students measure distances by applying logarithms (they're actually useful!) as well as calculating the slope and intercept of a line. One module uses Cepheid variable stars as distance indicators and establishes the necessary numerical relationship to use periods to determine distance. They then use this relationship and HST Cepheid variable data to calculate the distance to clusters of galaxies.

No Escape: The Truth About Black Holes
high school
This lesson uses graphics and HST images to trick students into learning some physics. In one module the student calculates the escape velocity for various objects and learns how to derive the equation. Another module asks the question, How many teachers do you have to stuff into a compact car until their combined gravity is so great that none of them can walk away?" This leads directly into the concept of black holes. Another module, "Black Hole Safari," will use STIS data as they become available. High school students will be asked to explain the concept of a black hole that a seventh grader would understand.

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Newsletter · Space Telescope ScienceNewslette r Space Telescope Science Institute · Institute

The Cosmic Origins Spectrograph (COS): High-Sensitivity UV Spectroscopy with HST
James C. Green and Jon A. Morse, CU/CASA jgreen@casa.colorado.edu, morsey@casa.colorado.edu

ASA recently selected the Cosmic Origins Spec trograph (COS) as a replacement instrument for the fourth HST servicing mission in 2002. COS will go into the bay currently occupied by COSTAR, which, after the 1999 servicing mission, will no longer be in use. COS is a high-throughput ultraviolet (UV) spectrograph that is optimized to observe faint point sources. COS will be, by a large factor, the most sensitive UV spectrograph ever flown aboard HST. It will bring the diagnostic power of UV spectroscopy to bear on such fundamental issues as the ionization and baryon content of the intergalactic medium and the origin of large-scale structure in the Universe; the ages, dynamics, and chemical enrichment of galaxies; and stellar and planetary origins. These science programs require having the capability to obtain moderate resolution (R > 20,000) spectroscopic observations of faint UV sources, such as distant quasars. We achieve high sensitivity in the UV by minimizing the number of reflections, which leads to an inher-

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ently simple spectrograph design (see Figure 1). The primary channel of COS employs a large entrance aperture, concave diffraction gratings, and a curved detector. The aperture is a two-arcsecond diameter circular field stop located on the HST focal surface near the point of maximum encircled energy. There is ONE reflection between the aperture and the detector. The grating has an aspheric concave surface figure specified to compensate for spherical aberration. Holographically-generated grooves provide dispersion and correct the astigmatism. Ion-etching creates a blaze that optimizes the efficiency over a narrow range of wavelengths. Two gratings, High Dispersion Channels 1 and 2, are used to cover the 1150 to 1775 A region at high resolution (R = 20,000 to 24,000). Each high-dispersion grating covers roughly 300 е in one exposure. A third grating, the High Sensitivity Channel, covers the entire 1230 to 2050 е region at lower resolution (R = 2500 - 3500). The three gratings are mounted on a rotating mechanism, similar in concept and function to the GHRS carrousel. The

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Figure 1: Schematic of the COS primary channel (as proposed). Light is received from the HST OTA through a 2-arcsecond round aperture, is dispersed by a concave diffraction grating, and finally is recorded on a curved double delay-line MCP detector adapted from the FUSE mission.

detector is a windowless microchannel-plate array, with an opaque CsI photocathode, and a double delay-line readout that has been adapted from the FUSE mission. COS will build on the legacies of Copernicus, IUE, GHRS, FOS, STIS, and in the future, FUSE, giving HST the greatest possible grasp of faint UV targets, a capability perhaps not available from future space-based observatories for decades. COS will complement and extend the suite of HST instruments, ensuring that, as recommended in the "HST & Beyond" report, Hubble maintains a powerful UV spectroscopic capability from 2002 until the end of its mission. Combining the large entrance aperture with highefficiency first-order gratings and a windowless detector, the primary channel of COS achieves effective areas about 18 times higher than STIS modes of comparable spectral resolution (Figure 2). The science drivers for COS include problems of fundamental importance in astrophysics and cosmology which require the moderate resolution and high throughput of COS, and four unique capabilities of HST: access to ultraviolet wavelengths, large collecting area, precise pointing stability, and excellent image quality. Below we describe several scientific issues that COS observations will address. Models for the formation of largescale structure and the reionization of the IGM will be constrained by observing distant quasars to measure the He II Gunn-Peterson effect, the structure of the Lyman-alpha forest, and the D/H ratio in primordial clouds. COS will be capable of obtaining moderate-resolution UV spectra of hundreds more quasars and AGNs than existing UV instruments. The COS database of absorption-line systems will have high enough spectral resolution and adequate S/N to


January 1998

10000

COS, STIS Effective Areas

COS (HDC1, HDC2) STIS (E140M, E230M) 1000 Effective Area (cm2)

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10 Proposed Long--Off of HDC2 1 1200 1300 1400 1500 1600 Wavelength (е) 1700 1800 1900

COS, STIS Effective Areas

COS (HSC) STIS (G140L, G230L)

1000

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1200

1300

1400

1500 1600 Wavelength (е)

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Figure 2: Effective area curves (including slit losses) for the spectroscopic modes of the primary channel of COS. Curves for STIS modes of similar spectral resolution are shown for comparison. determine accurate column densities, abundances, and kinematics of intergalactic matter at epochs when the first galaxies were formed and the first heavy elements were synthesized. COS will be used to determine abundances and kinematics of hot gas in galaxy halos, the impact of violent starbursts and supernovae on interstellar and intergalactic environments, and the ages of globular clusters. The numerous quasar sight-lines accessible to COS will intersect hot galaxy halos over a large redshift range. COS spectra will constrain galaxy evolution models by mapping the production of metal-enriched gas through time. COS will also observe nearby starbursting systems over a range of metallicity. These spectra will be used to model the chemical enrichment of the interstellar medium, and as templates for deriving the properties of high-z galaxies. COS UV spectra of horizontal-branch stars in globular clusters will allow significant refinement of globular cluster age estimates. which may help to reconcile the ages of the

oldest stars in galaxies with the age of the Universe derived from recent measurements of the Hubble constant and closure parameter. The origins of stellar and planetary systems will be investigated by studying the physical processes and chemical abundances in the cold ISM. For the first time in the UV, COS will observe sight-lines toward hot, embedded stars that will probe dense, molecular regions where the star formation process begins. COS data will also provide clues to the conditions and composition of the outer solar nebula. The high sensitivity of COS will allow an order of magnitude more background stars to be observed in stellar occultation studies of planetary and cometary atmospheres. COS will break new ground with direct moderate-resolution UV observations of Pluto and Triton that will be used to detect fluorescence emission from volatile gases as these bodies both undergo rare seasonal changes during the first decade of the next century. COS will be used to observe very faint targets, taking full advantage of HST capabilities (large aperture, UV coatings, excellent pointing and image quality). COS is optimized to observe faint UV sources with spectral resolution high enough to determine the physical conditions in a broad range of astrophysical environments. Its design meets programmatic requirements for reliability and redundancy, and its simplicity and efficient operation ensure a high science return. With these capabilities, we anticipate a high degree of interest in using COS throughout the worldwide astronomical community. NASA has asked the COS team to evaluate extending the wavelength coverage of COS to include the 1800 to 3200 Angstrom region by adding a secondary channel. This channel is partially to back up the STIS near-UV spectroscopic modes and also to restore the capability to observe faint targets that has been mitigated by the high background of the STIS near-UV MAMA. Our preliminary design for
continued page 21

Effective Area (cm2)

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Newsletter · Space Telescope ScienceNewslette r Space Telescope Science Institute · Institute

The Starburst Dwarf Galaxy NGC 5253.
Daniela Calzetti, STScI, and Gerhardt R. Meurer, JHU calzetti@stsci.edu, meurer@pha.jhu.edu

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tarbursts are galaxies undergoing a major star formation event, generally in their central region. Since they are producing many massive, ionizing stars, starbursts typically have optical-infrared spectra which are dominated by the emission lines of the ionized gas. Their spectra distributions can be both bright in the ultraviolet (UV) and in the far infrared: the far infrared (FIR) radiation is emitted by the dust heated by the massive stars which are also responsible for the UV radiation. Starburst galaxies occupy an important niche in the framework of galaxy evolution, as they are the primary site of massive star formation. A significant fraction of the star formation in the local Universe appears to occur in such high-intensity episodes (Heckman 1997); starbursts are relevant for understanding the cosmic star-formation and metalenrichment histories (Madau et al. 1996), the nature of the high-redshifts galaxies (Steidel et al. 1996; Giavalisco, Steidel & Macchetto 1996), and of the faint blue galaxies at intermediate redshifts. However, a number of questions on the starburst's fundamental physics and evolution remain unanswered. To mention a few: How long does a starburst last (Calzetti 1997)? What is the star formation history of a burst, and what type of stellar population is left behind? What is the role of dust in determining the starburst's morphology (Calzetti, Kinney, & Storchi-Bergmann 1994)? To answer these questions, we turn to the nearest starbursts, to map their stellar populations, ages, dust content, and, ultimately, to disentangle their spatial and temporal evolution. The dwarf galaxy NGC 5253 is an ideal laboratory for such study. This galaxy is located in the Centaurus Group, at a distance of only 4.1 Mpc

from our own Galaxy (Sandage et al. 1994). A burst of star formation is currently taking place in the central ~20 arcsec region of this otherwise quiescent galaxy. WFPC2 images in V, I, H, and H of NGC 5253 were obtained in May 1996, and supplemented with archival UV images centered at 2600 е, in order to create a UV-optical baseline. The purpose was to study the recent star formation history of the starburst while disentangling the ages of the stellar population from the effects of dust reddening (Calzetti et al. 1997). At the distance of the galaxy, one WF pixel corresponds to 2 pc, a scale comparable with the typical size of stellar clusters (van den Bergh, Morbey & Pazder 1991). The left panel of Figure 1 shows the inner 30 x 30 arcsec of the galaxy as seen in the UV filter, while the right panel shows the same region in the I filter. The relative brightness of the various features (stars, clusters) is clearly different between the two bands, showing the combined effects of dust, reddening, and aging (thus reddening too) of the stellar population. The morphology of the ionized gas is shown in Figure 2. The ionized gas emission is a tracer of the current star formation (Kennicutt 1983), while the UV emiss