Astronomers using the NASA/ESA/CSA James Webb Space Telescope have observed the Hubble Ultra Deep Field (HUDF), an area of deep space with nearly 10,000 galaxies in the constellation Fornax.
This Webb image shows the Hubble Ultra Deep Field, an area of deep space with thousands of galaxies in various shapes and sizes on a black background. Image credit: NASA / ESA / CSA / Webb / G. Östlin / P. G. Perez-Gonzalez / J. Melinder / JADES Collaboration / M. Zamani, ESA & Webb.
The original HUDF images were pioneering deep-field observations with Hubble published in 2004.
They probed more deeply than ever before and revealed a menagerie of galaxies dating back to less than a billion years after the Big Bang.
The area was subsequently observed many times by Hubble and other telescopes.
“The field shown here, known as the MIRI Deep Imaging Survey (MIDIS) region, was observed with the shortest-wavelength filter of Webb’s Mid-Infrared Instrument (MIRI) for nearly 100 hours,” the Webb astronomers said in a statement.
“This is Webb’s longest observation of an extragalactic field in one filter so far, producing one of the deepest views ever obtained of the Universe.”
“Combined with data from Webb’s Near-Infrared Camera (NIRCam), this image allows astronomers to explore how galaxies formed and evolved over billions of years.”
“These deep observations have revealed more than 2,500 sources in this tiny patch of sky.”
“Among them are hundreds of extremely red galaxies — some of which are likely massive, dust-obscured systems or evolved galaxies with mature stars that formed early in the Universe’s history.”
“Thanks to Webb’s sharp resolution, even at mid-infrared wavelengths, researchers can resolve the structures of many of these galaxies and study how their light is distributed, shedding light on their growth and evolution.”
In the new Webb image of HUDF, the colors that have been assigned to different kinds of infrared light highlight the fine distinctions astronomers can make with these deep data.
“Orange and red represent the longest mid-infrared wavelengths,” the astronomers said.
“The galaxies in these colors have extra features — such as high concentrations of dust, copious star formation, or an active galactic nucleus (AGN) at their center — which emit more of this farther infrared light.”
“Small, greenish-white galaxies are particularly distant, with high redshift.”
“This shifts their light spectrum into the peak mid-infrared wavelengths of the data, which are depicted in white and green.”
“Most of the galaxies in this image lack any such mid-infrared boosting features, leaving them most bright at shorter near-infrared wavelengths, which are depicted with blue and cyan colors.”