NGST: The Early Days of JWST

Nearly 30 years ago Riccardo Giaconni, then the Institute Director, challenged Peter Stockman (Research Branch Head) and me (Deputy Director) to “think about the next major mission beyond Hubble.” This was still several years before the launch of Hubble, during the period after the Challenger accident when the future looked unclear. Riccardo was concerned that major missions take a very long time between inception and commissioning, longer typically than the then-expected 15-year life for Hubble. While I cannot remember the details of exactly when this took place, I can remember thinking that this was somewhat crazy given the work remaining on Hubble. But resisting Riccardo without well-formulated arguments was not likely to be successful— especially on this topic, given that Riccardo was one of the few people at that time to have done major space science missions.

 

Preparing for the first James Webb Space Telescope proposals

The integration and testing of the James Webb Space Telescope is on schedule for a nominal October 2018 launch, and recently its beautiful mirror assembly was revealed in the clean room. This means that we are now a year from the first open call for proposals for observing with Webb—namely the Early Release Science (ERS) program call—planned for May 2017. The ERS is a program awarding approximately 500 hours of observing time early in Webb Cycle 1 to exciting science programs for immediate release to the astronomical community. Following this, a call for the full Cycle 1 General Observer program will be issued in November 2017.

 

Previews of the James Webb Space Telescope:
The Frontier Fields Program

The Frontier Fields program is the latest chapter in Hubble’s hallowed tradition of deep-field initiatives. This time, by combining deep Hubble imaging with gravitational lensing, astronomers have observed the faintest sources ever studied, even fainter than those revealed in the Ultra-Deep Field. This three-year Director’s Discretionary program began in October 2013 and will conclude this coming September. Deep optical and near-infrared imaging of six galaxy clusters and six blank fields with both Hubble and Spitzer is almost complete. Supporting data have also been obtained with Chandra, Subaru, VLT, and other observatories. The ultra-faint objects revealed in the Frontier Fields are giving us a preview of the universe we will observe with the James Webb Space Telescope.

 
 
 
 
 

Nearly 30 years ago Riccardo Giaconni, then the Institute Director, challenged Peter Stockman (Research Branch Head) and me (Deputy Director) to “think about the next major mission beyond Hubble.” This was still several years before the launch of Hubble, during the period after the Challenger accident when the future looked unclear. Riccardo was concerned that major missions take a very long time between inception and commissioning, longer typically than the then-expected 15-year life for Hubble. While I cannot remember the details of exactly when this took place, I can remember thinking that this was somewhat crazy given the work remaining on Hubble. But resisting Riccardo without well-formulated arguments was not likely to be successful— especially on this topic, given that Riccardo was one of the few people at that time to have done major space science missions.

 
 

The integration and testing of the James Webb Space Telescope is on schedule for a nominal October 2018 launch, and recently its beautiful mirror assembly was revealed in the clean room. This means that we are now a year from the first open call for proposals for observing with Webb—namely the Early Release Science (ERS) program call—planned for May 2017. The ERS is a program awarding approximately 500 hours of observing time early in Webb Cycle 1 to exciting science programs for immediate release to the astronomical community. Following this, a call for the full Cycle 1 General Observer program will be issued in November 2017.

The Frontier Fields program is the latest chapter in Hubble’s hallowed tradition of deep-field initiatives. This time, by combining deep Hubble imaging with gravitational lensing, astronomers have observed the faintest sources ever studied, even fainter than those revealed in the Ultra-Deep Field. This three-year Director’s Discretionary program began in October 2013 and will conclude this coming September. Deep optical and near-infrared imaging of six galaxy clusters and six blank fields with both Hubble and Spitzer is almost complete. Supporting data have also been obtained with Chandra, Subaru, VLT, and other observatories. The ultra-faint objects revealed in the Frontier Fields are giving us a preview of the universe we will observe with the James Webb Space Telescope.

Exoplanet researchers are counting down the days until the launch of the long-awaited James Webb Space Telescope. Webb will transform our ability to unveil the atmospheres of planets transiting close to their parent stars. The community is in the process of developing tools, obtaining complementary observations, and planning for the first round of Webb observing proposals.

The JSTAC’s role, distilling its charge down to a key phrase, is to advise the Institute Director on “maximizing JWST’s scientific productivity” during its operational life. While this enunciation is simple and focused, the challenges during science operations for a mission of the complexity of JWST facing the partner agencies (NASA, ESA, and CSA) and the Institute, and an advisory committee like JSTAC, are similarly wide-ranging and complex. JSTAC members were chosen across the three-agency partnership to have extensive background with space science missions. The Institute’s Director formed the JSTAC in 2009 after consulting the partner agencies. The Institute Director appoints the JSTAC, and its 18 members include representatives from the US, European, and Canadian astronomical communities and ex-officio observers from NASA, ESA, and CSA. JSTAC submits recommendations to the Institute’s Director.

Now in its 26th year of operations, Hubble is still going strong, producing science that continues to challenge and expand our understanding of the universe. From predicting supernovae, to finding the most distant spectroscopically-confirmed galaxy, to detecting water vapor plumes above the surface of Europa, the breadth of Hubble’s science is vast and continues to grow. After 26 years and over 142,000 orbits of the Earth, Hubble is a healthy, mature, observatory, and all subsystems are operating in a nominal status; extrapolations predict mission continuation beyond 2020. In this newsletter article we provide a brief “State of the Observatory” overview of recent activities.

The Legacy ExtraGalactic UV Survey (LEGUS)

The combination of UV capability, high-angular resolution, and large field of view afforded by the Hubble Space Telescope is the foundation of the Legacy ExtraGalactic UV Survey (LEGUS), GO-13364. LEGUS, a Cycle 21 Hubble Treasury program, was designed with the main goal of providing a definite characterization of the links between star formation on two fundamental scales: those of individual stars, stellar clusters, and associations on parsec scales; and of galaxy disks on kilo-parsec scales (Calzetti et al. 2015a).

The past 5-10 years have seen major breakthroughs in our knowledge of exoplanet populations. With more than 1600 exoplanets detected by the Kepler mission, we know that our solar system is not unique in the universe, and that planets are actually relatively common: Two sun-like stars out of three have a planet smaller than Neptune within 0.75 AU [1], while every dwarf M star – which are much more numerous than stars like our Sun – hosts at least two planets within similar orbits [2].

In The Realm of Nebulae, Edwin Hubble wrote: “The history of astronomy is a history of receding horizons”, a quote which could not be more fitting to describe the story and the discoveries of the Hubble Space Telescope. During its 26 years in space, Hubble has steadily pushed our observational horizon to earlier and earlier cosmic times and transformed our view and understanding of how galaxies built up and evolved in the early universe. Starting from the Hubble Deep Field (Williams et al. 1996) and the discovery of z~4 galaxies about 12 Billion years in the past (Madau et al. 1996), HST has now found galaxies as far back as z~10, when the universe was only about 3% of its current age (e.g. Bouwens et al. 2011, Ellis et al. 2013, Oesch et al. 2014). This is a stunning achievement, and one, which few expected to be possible when HST was built and launched.

For more than two decades, Hubble’s images have engaged the public and bolstered interest in science and astronomy. Scientists and the public alike have been inspired by the fundamental questions that are often triggered by Hubble discoveries: Where do we come from? Where we are going? Are we alone? The new exhibit, Our Place in Space, is designed to capture the spirit of wonder and inspiration generated when we pause to ponder humanity’s place in the grand scheme of the cosmos. To do this in a public exhibit, we ask astronomers and artists to communicate their interpretation of where we are and belong, how our past affects us and what our future might be -- through imagery and art. The exhibit themes present humanity’s adventure in space from local exploration in the solar system out to discoveries at the edge of the universe.

In 1980, a paper by D. W. Davies pointed out that a 2.4-meter telescope like Hubble could reasonably expect to detect an exoplanet in reflected light—provided that one could integrate sufficiently long to overcome the overwhelming background caused by a host star’s point spread function (PSF), the diffraction pattern of a telescope created by the shape of the primary mirror, the support structure/secondary mirror, and any pupil plane aberrations (Davies 1980). More careful analysis of the Hubble Space Telescope’s expected optical performance showed that the roughness of the mirror and its associated aberrations made exoplanet imaging prohibitive for even the closest of stars (Brown & Burrows 1990).

STScI hosted a science workshop from October 5-7 2015 on Feedback in the Magellanic Clouds. This event focused on stellar and galactic feedback in two of our nearest dwarf-galaxy neighbors, the Large and Small Magellanic Clouds. It featured 75 registered participants, 32 posters, 13 invited talks, and a range of contributed talks and discussions.

Big data is everywhere, and astronomy is no exception. Our ability as a society to measure ever more about consumers, take ever more pictures, and send ever more messages has been mirrored in our ability to acquire ever more digital information about the cosmos. Experiments of the next decade like Large Synoptic Survey Telescope and the Square Kilometer Array are slated to ingest an unprecedented volume of astronomical data.

Data archiving is a crucial component of the operation of an astronomical observatory. Archives ensure the legacy of the observatory, and act as multipliers for its science output, by enabling science investigations unrelated to those in the proposals that obtained the data.

The Wide Field Infrared Survey Telescope (WFIRST) got its formal start in February 2016, when NASA advanced it into the mission Formulation Phase, with launch aimed for the mid 2020s. This marked the completion of several years of pre-formulation work, capped by a successful Mission Concept Review in December 2015.