One of the emerging themes in cosmology is “finding ways to study things we really wanted to use JWST to study.” While the potentially next great orbiting observatory has finally made it to the region from which it will be launched, you can’t count your orbiting telescopes until they have achieved first light, and as someone who planned to use the Japanese ASTRO-E telescope for my dissertation, only to see it fail to reach its intended orbit, I have somewhat dedicated my career seriously to not counting telescopes before they launch and return healthy images.

Seriously, don’t do it. That path only leads to heartache.

And for the folks who have answered calls for observing proposals, sat on science committees, and otherwise tried to plan to use the JWST for the past decade, as it has over and over remained “a couple of years” or less from launch, finding alternative ways to do their science has become a necessity.

One of JWST’s science goals was to directly observe galaxies in the early universe and answer questions about how they formed and evolved in the first few billion years. These early galaxies are too faint for the largest Earth-based telescopes to observe, and Hubble, while awesome, is actually a smallish telescope. 

Without the technology to directly observe these systems, we have to find JWST alternatives, and luckily, as we’ve discussed before, the universe provides. High-mass systems, like massive galaxy clusters, can use their mass to bend light in the same way a lens bends light, and when a bunch of light intended for other parts of the universe gets focused our way, the too faint to see can become bright enough to observe. In the past on this show, we’ve talked about a variety of individual systems used to study specific aspects of distant galaxies.

Now, a survey looks at many different gravitationally lensed galaxies to try and understand how galaxies evolved in the early universe by finding local copies. This was a two-step process. Researchers first looked at lensed systems to figure out their basic characteristics, and then they used data from the Survey for High-z Absorption Red and Dead Sources (SHARDS) to look for nearby analogs to those distant systems. According to Alex Griffiths, lead author of a new study in the Monthly Notices of the Royal Astronomical Society: Until we have the new James Webb Space telescope, we cannot observe the first galaxies ever formed, they are just too faint. So we looked for similar beasts in the nearby Universe and we dissected them with the most powerful telescopes we currently have.

In total, they identified 27 dwarf galaxies to study and found that the systems showed signs of bingeing star formation and then undergoing quiet lulls. Griffiths goes on to explain: …the start of galaxy formation is fitful, like a jerky car engine, with periods of enhanced star formation followed by sleepy intervals. It is unlikely that galaxy mergers have played a substantial role in the triggering of these bursts of star formation and it is more likely due to alternative causes that enhance gas accretion, we need to search for those alternatives.

There is still so much science we, as a research field, require a large infrared space telescope to accomplish. We hope to see JWST launch this winter and deploy successfully. Until then, we celebrate the scientists who have found alternatives to do the research they want.

More Information

University of Nottingham press release

“Emission line galaxies in the SHARDS Frontier Fields – I. Candidate selection and the discovery of bursty Hα emitters,” Alex Griffiths et al., 2021 October 21, Monthly Notices of the Royal Astronomical Society