The NASA/ESA/CSA James Webb Space Telescope has topped itself once again, delivering on its promise to push the boundaries of its observations closer to cosmic dawn with the confirmation of a bright galaxy that existed 280 million years after the Big Bang.
By now Webb has established that it will eventually surpass virtually every benchmark it sets in these early years, but the newly confirmed galaxy, MoM-z14, holds intriguing clues to the Universe’s historical timeline and just how different a place the early Universe was than astronomers expected.
“With Webb, we are able to see galaxies farther than ever have before. We find that the early Universe looks nothing like what we predicted, which is both challenging and exciting,” said Rohan Naidu of the Massachusetts Institute of Technology’s (MIT) Kavli Institute for Astrophysics and Space Research, lead author of a paper on galaxy MoM-z14 published in the Open Journal of Astrophysics.
Due to the expansion of the Universe that is driven by dark energy, discussion of physical distances and 'years ago' becomes tricky when looking this far. Using Webb’s NIRSpec (Near-Infrared Spectrograph) instrument, astronomers confirmed that MoM-z14 has a cosmological redshift [1] of 14.44, meaning that its light has been travelling through (expanding) space, being stretched and 'shifted' to longer, redder wavelengths, for about 13.5 of the Universe’s estimated 13.8 billion years of existence.
“We can estimate the distance of galaxies from images, but it’s really important to follow up and confirm with more detailed spectroscopy so that we know exactly what we are seeing, and when,” said Pascal Oesch of the University of Geneva in Switzerland, co-principal investigator of the survey.
MoM-z14 is one of a growing group of surprisingly bright galaxies in the early Universe – 100 times more than theoretical studies predicted before the launch of Webb, according to the research team.
“There is a growing chasm between theory and observation related to the early Universe, which presents compelling questions to be explored going forward,” said Jacob Shen, a postdoctoral researcher at MIT and a member of the research team.
One place researchers and theorists can look for answers is the oldest population of stars in the Milky Way galaxy. A small percentage of these stars have shown high amounts of nitrogen, which is also showing up in some of Webb’s observations of early galaxies, including MoM-z14.
“We can take a page from archeology and look at these ancient stars in our own galaxy like fossils from the early Universe, except in astronomy we are lucky enough to have Webb seeing so far that we also have direct information about galaxies during that time. It turns out we are seeing some of the same features, like this unusual nitrogen enrichment,” said Rohan.
With galaxy MoM-z14 existing only 280 million years after the Big Bang, there was not enough time for generations of stars to produce such high amounts of nitrogen in the way that astronomers would expect. One theory the researchers note is that the dense environment of the early Universe resulted in supermassive stars capable of producing more nitrogen than any stars observed in the local Universe.
The galaxy MoM-z14 also shows signs of clearing out the thick, primordial hydrogen fog of the early Universe in the space around itself. One of the reasons Webb was originally built was to define the timeline for this “clearing” period of cosmic history, which astronomers call reionization. This is when early stars produced light of high enough energy to break through the dense hydrogen gas of the early Universe and begin travelling through space, eventually making its way to Webb, and us. Galaxy MoM-z14 provides another clue for mapping out the timeline of reionization, work that was not possible until Webb lifted the veil on this era of the Universe.
Even before Webb’s launch, there were hints that something very unanticipated happened in the early Universe, when the NASA/ESA Hubble Space Telescope discovered the bright galaxy GN-z11 400 million years after the Big Bang. Webb confirmed the galaxy’s distance – at the time the most distant ever. From there Webb has continued to push back farther and farther in space and time, finding more surprisingly bright galaxies like GN-z11.
As Webb continues to uncover more of these unexpectedly luminous galaxies, it’s clear that the first few were not a fluke. As Webb continues to uncover more of these unexpectedly luminous galaxies, it’s clear that the first few were not a fluke. “It’s an incredibly exciting time, with Webb revealing the early Universe like never before and showing us how much there still is to discover” added Yijia Li, a graduate student at the Pennsylvania State University and a member of the research team.
Notes
[1] The Universe is expanding, and that expansion stretches light traveling through space in a phenomenon known as cosmological redshift. The greater the redshift, the greater the distance the light has traveled.More information
Webb is the largest, most powerful telescope ever launched into space. Under an international collaboration agreement, ESA provided the telescope’s launch service, using the Ariane 5 launch vehicle. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission and for the procurement of the launch service by Arianespace. ESA also provided the workhorse spectrograph NIRSpec and 50% of the mid-infrared instrument MIRI, which was designed and built by a consortium of nationally funded European Institutes (The MIRI European Consortium) in partnership with JPL and the University of Arizona.
Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).
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