Magic! Where did so many galaxies in the universe come from?

A giant galaxy called the Shipyard has been discovered 11 billion light years away

A similar protocluster may have created our own Milky Way galaxy

Astronomers have discovered a giant shipyard that is the cradle of galaxies. Our own Milky Way galaxy was born in a similar cluster.

The massive structure, known as the protocluster, contains more than 60 galaxies. It's 11 billion light years away from Earth. That's so far away that scientists can only observe a portion of its 3-billion-year-old history.

In January 2021, researchers published a paper about a protocluster called G237, whose existence has now been confirmed by an international team of astronomers. The astronomers published their follow-up findings Oct. 26 in the journal Astronomy and Astrophysics.

"You can think of a protocluster like G237 as a kind of galaxy shipyard, where huge galaxies are assembled. When the universe was only 3 billion years old, only this structure existed, "study co-author Branda Frye, an associate professor of astronomy at the University of Arizona, said in a statement on the study.

According to Ferre, gravity pulls stars and other objects together to form galaxies, which tend to cluster further. But partly because the light from these clusters is too faint to be seen in visible light, scientists know very little about protoclusters.

The researchers first observed G237 in the far infrared region of the electromagnetic spectrum using the European Space Agency's Planck telescope.

Now, scientists have confirmed its existence with follow-up observations. For the observations, they used the Large Binoculars in Arizona, the Subaru Telescope in Japan, the Herschel Space Astronomy Observatory, the Spitzer Space Telescope and related archival data.

Early observations of G237 suggest that it is creating stars at an extremely high but unsustainable rate. "Every one of the 63 galaxies found so far in G237 is like a high-velocity star factory," Ferre said. It's as if galaxies are working overtime to assemble stars.

Hydrogen is an important fuel for star formation, but astronomers initially encountered a puzzling problem: the protoclusters didn't seem to have enough hydrogen to support such a high rate of star formation.

The researchers found that some of the stars they observed were born in galaxies unrelated to G237. After removing these irrelevant observations, the protocluster remains highly productive, so they believe that clusters like G237 could get enough hydrogen from the dark strips, or gas filaments. These filaments of gas link different galaxies together to create a "cosmic web". The intersection of these dark bars is where these protoclusters are born. That means protoclusters like G237 could get enough hydrogen to go on a star-making spree.

"We have completed the jigsaw puzzle of a successful galaxy shipyard that efficiently assembles galaxies and their stars, with a constant supply of energy," Ferre said.

The Spitzer Space Telescope, or Space Infrared Telescope Facility (SIRTF), was launched in 2003 and decommissioned on January 30, 2020. It is the third space telescope to serve infrared astronomy, following IRAS (1983) and ISO (1995-98). The Spitzer Space Telescope was also the first spacecraft to use Earth to track its orbit in a way that was later used by the Kepler probe.

Spitzer's mission was planned for two and a half years, and before launch scientists expected the mission to stretch to five years or more before its supply of liquid helium ran out. Spitzer actually ran out of liquid helium on May 15, 2009, to cool the telescope to the freezing temperatures needed to operate, making most of its instruments unusable. However, the two modules with the shortest wavelengths of the IRAC camera continued to operate at the same sensitivity as before the cryogenic exhaustion and continued to be used in the "Spitzer Warming Period Mission" in early 2020.

The IRAC's two shortwave modules, operating at 28.7K during the warm-phase mission, are also not expected to degrade much compared to the normal-state mission. These data, along with previous ones, are stored in the Infrared Science Archive (IRSA).

On December 18, 2003, in keeping with NASA tradition, the telescope was renamed after a successful demonstration. Most telescopes named by committees of scientists are named after famous dead scientists, but at SIRTF the scientists took a different tack and chose the name of a publicly available astronomy competition. The name comes from Lyman Spitzer, the astronomer who popularized space telescopes in the 1940s. He wrote a report for RAND in 1946 describing the advantages of an extraterrestrial observatory and how it could be achieved with existing or soon-to-be-available technology. It was because of his pioneering contributions to rocketry and astronomy, as well as "vision and leadership in articulating the benefits of realizing a space telescope program," that such a great telescope bears Spitzer's name.