Leicester Astronomers Looking Ahead to First Light for Webb

Leicester astronomers and planetary scientists are among the thousands of international scientists who have been awarded time on the hotly-anticipated James Webb Space Telescope, and are expecting a flood of new scientific data in 2022.

The selection of the General Observer programmes for the telescope’s first year of science, known as Cycle 1, were announced at the end of March 2021, providing the worldwide astronomical community with the first extensive opportunities to investigate scientific targets with Webb. More than 1,000 proposals were submitted by from 44 countries for a portion of the 6,000 observing hours available in Webb’s first year. Proposals from Leicester scientists were among the 286 selected proposals, both as principal investigators (PIs) or co-investigators (co-Is).

Webb will begin taking data in 2022 after the spacecraft launches in late 2021, unfolds, travels a million miles, and checks the functioning of all of its instruments. In the following paragraphs, we highlight some of the exciting observations awarded to Leicester scientists in astronomy, exoplanets, planet formation, and Solar System science.

Astronomy

Nial Tanvir and Rhaana Starling are co-Is of a programme to map emission and absorption line metallicities in the host galaxies of Gamma Ray Bursts (GRBs) (GO2344). Gamma-ray bursts are brief flashes of high energy emission that signal the death of a massive star or merger of a compact binary. These transient events pinpoint the location of distant star-forming galaxies that are often not found by traditional surveys. They will observe ten host galaxies of gamma-ray bursts at a time in the Universe’s history known as cosmic noon, when star formation in massive galaxies was at its peak.

Paul O’Brien is a co-I on a proposal led by Andrew Levan to observe the electromagnetic counterpart of a gravitational wave event to study the production of heavy elements (GO2395). This is a Target of Opportunity proposal to be triggered should a gravitational wave event be observed during Cycle 1.

Tuomo Tikkanen and John Pye are Co-Is in the ‘PRIMER’ (Public Release IMaging for Extragalactic Research) programme led by James Dunlop (Edinburgh), one of the largest programmes in Cycle 1 (GO1837). PRIMER will provide the astronomical community with an early, large-area, homogenous, deep JWST infrared imaging survey to revolutionise our knowledge of early galaxy and black-hole formation and evolution out to the highest redshifts yet probed. The PRIMER survey is predicted to reveal around 120,000 galaxies, the majority of which are expected to be newly discovered. Tikkanen and Pye are long-standing members of the European-Consortium JWST Mid-InfraRed Instrument development team, and heavily involved in preparations for the Consortium’s ‘Guaranteed Time’ observations, which will have a close relation to the PRIMER survey.

Exoplanets and Formation

Michael Roman is co-I on a proposal to study the archetypal sub-Neptune GJ1214b, led by Jacob Bean (GO1803). They aim to observe the emission spectra from GJ1214b over a full orbit with the MIRI instrument that Leicester helped to build. Combined with near-IR observations, these will provide powerful constraints on GJ1214b’s atmospheric composition and structure, which remains obscured in transmission spectra likely owing to thick hazes.

Giovanni Rosotti is a Co-I on a proposal to use water as a tracer of pebble delivery to rocky planets, led by Andrea Banzatti (Texas State University) (GO1640). They will observe water lines in the mid infrared in a few proto-planetary discs around young stars. This water is believed to be released by pebbles, as they drift from the cold, outer regions of the discs toward the warmer regions around the star. They aim to test this hypothesis by measuring with JWST the water content in the terrestrial planet-forming region and linking it with the pebbles in the outer disc we trace through ALMA images.

Planetary Science

Leigh Fletcher is a PI on a target-of-opportunity programme (GO1424) to observe Jupiter and/or Saturn in the event of an enormous impact (like Shoemaker-Levy 9 in 1994, or the Wesley impactor in 2009), or a rare storm event. Observations will rely on triggers from the amateur community, and will occur some ~2 weeks after the impact/storm eruption to understand the atmospheric physics and chemistry at work. Both NIRSPEC and MIRI spectral cubes will be acquired. Fletcher is also co-I on a programme (GO1604) to observe Neptune in the mid-infrared with MIRI, to study how the planet’s dynamic storms affect its temperature and composition over short spans of time.

These Guest Observer programmes supplement the guaranteed-time (GTO) and early-release science (ERS) proposals in Solar System science. Specifically, Fletcher leads programmes to study Jupiter’s Great Red Spot (GTO1246), Saturn’s summer pole and rings (GTO1247), and to acquire global mid-IR maps of Uranus (GTO1248) and Neptune (GTO1249) to reveal the properties of their stratospheres for the first time. Finally, Henrik Melin and Leigh Fletcher are co-Is on an ERS programme (ERS1373) to study Jupiter’s atmosphere and satellite system as an early test of Webb’s capabilities to explore bright, extended, rotating targets.