Hubble Space Telescope’s Deep Field revealed thousands of galaxies in a seemingly empty spot in the sky. Now, the James Webb Space Telescope has taken deep field observations to the next level with its COSMOS-Web survey, revealing 25,000 galaxies in just six pictures, the first from this new survey.
“It’s incredibly exciting to get the first data from the telescope for COSMOS-Web,” said principal investigator Jeyhan Kartaltepe, from the Rochester Institute of Technology’s School of Physics and Astronomy, in press release. “Everything worked beautifully and the data are even better than we expected. We’ve been working really hard to produce science quality images to use for our analysis and this is just a drop in the bucket of what’s to come.”
The NASA/European Space Agency (ESA)/Canadian Space Agency (CSA) James Webb Space Telescope (JWST) mission continues to dazzle and amaze with every image it beams back to Earth, and a recent observation depicting not one, not two, but three images of the same galaxy has been no different, as they proudly tweeted on February 28, 2023.
In the first data taken last summer with the Near Infrared Camera (NIRCam) on the new James Webb Space Telescope, astronomers found six galaxies from a time when the Universe was only 3% of its current age, just 500-700 million years after the Big Bang. While its incredible JWST saw these galaxies from so long ago, the data also pose a mystery.
These galaxies should be mere infants, but instead they resemble galaxies of today, containing 100 times more stellar mass than astronomers were expecting to see so soon after the beginning of the Universe. If confirmed, this finding calls into question the current thinking of galaxy formation and challenges most models of cosmology.
Astronomers have studied the star formation process for decades. As we get more and more capable telescopes, the intricate details of one of nature’s most fascinating processes become clearer. The earliest stages of star formation happen inside a dense veil of gas and dust that stymies our observations.
But the James Webb Space Telescope sees right through the veil in its images of nearby galaxies.
Humanity is in a back-and-forth relationship with nature. First, we thought we were at the center of everything, with the Sun and the entire cosmos rotating around our little planet. We eventually realized that wasn’t true. Over the centuries, we’ve found that though Earth and life might be rare, our Sun is pretty normal, our Solar System is relatively non-descript, and even our galaxy is one of the billions of spiral galaxies, a type that makes up 60% of the galaxies in the Universe.
But the Illustris TNG simulation shows that the Milky Way is special.
In the 1970s, astronomers discovered that the persistent radio source at the center of our galaxy was a supermassive black hole (SMBH). Today, this gravitational behemoth is known as Sagittarius A* and has a mass roughly 4 million times that of the Sun. Since then, surveys have shown that SMBHs reside at the center of most massive galaxies and play a vital role in star formation and galactic evolution. In addition, the way these black holes consume gas and dust causes their respective galaxies to emit a tremendous amount of radiation from their Galactic Centers.
These are what astronomers refer to as Active Galactic Nuclei (AGN), or quasars, which can become so bright that they temporarily outshine all the stars in their disks. In fact, AGNs are the most powerful compact steady sources of energy in the Universe, which is why astronomers are always trying to get a closer look at them. For instance, a new study led by the University of California, Santa Cruz (UCSC) indicates that scientists have substantially underestimated the amount of energy emitted by AGN by not recognizing the extent to which their light is dimmed by dust.
Using telescopes that study the sky in the microwave part of the electromagnetic spectrum, astronomers have successfully mapped the structure of the magnetic field of the Milky Way galaxy. While magnetic fields are difficult to measure in space, an international team of astronomers used the Teide Observatory on Tenerife in the Canary Islands to conduct 10 years of observations.
For the first time this week, photos from the James Webb Space Telescope (JWST) revealed that stellar bars were present in some galaxies as far back as 11 billion years ago. Stellar bars are a defining feature of about two-thirds of all spiral galaxies in the Universe, including our own Milky Way. The discovery has implications for astronomers’ understanding of galactic evolution, indicating that bars form very quickly and may persist for much of a galaxy’s lifespan, influencing its shape and structure.
Although dark matter is a central part of the standard cosmological model, it’s not without its issues. There continue to be nagging mysteries about the stuff, not the least of which is the fact that scientists have found no direct particle evidence of it. Despite numerous searches, we have yet to detect dark matter particles. So some astronomers favor an alternative, such as Modified Newtonian Dynamics (MoND) or modified gravity model. And a new study of galactic rotation seems to support them.
Studying the large-scale structure of our galaxy isn’t easy. We don’t have a clear view of the Milky Way’s shape and features like we do of other galaxies, largely because we live within it. But we do have some advantages. From within, we’re able to carry out close-up surveys of the Milky Way’s stellar population and its chemical compositions. That gives researchers the tools they need to compare our own galaxy to the many millions of others in the Universe.
This week, an international team of researchers from the USA, UK, and Chile released a paper that does just that. They dug through a catalogue of ten thousand galaxies produced by the Sloan Digital Sky Survey, searching for galaxies with similar attributes to our own.
They discovered that the Milky Way has twins – many of them – but just as many that are only superficially similar, with fundamental differences buried in the data. What they discovered has implications for the future evolution of our own galaxy.