The Earliest Merging Quasars Ever Seen

This illustration depicts two quasars in the process of merging. Using both the Gemini North telescope, one half of the International Gemini Observatory, which is supported in part by the U.S. National Science Foundation and operated by NSF NOIRLab, and the Subaru Telescope, a team of astronomers have discovered a pair of merging quasars seen only 900 million years after the Big Bang. Not only is this the most distant pair of merging quasars ever found, but also the first confirmed pair found in the period of the Universe known as Cosmic Dawn.

Studying the history of science shows how often serendipity plays a role in some of the most important discoveries. Sometimes, the stories are apocryphal, like Newton getting hit on the head with an apple. But sometimes, there’s an element of truth to them. That was the case for a new discovery of the oldest pair of merging quasars ever discovered – and it all started with a pair of red blots on a picture.

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The JWST is Re-Writing Astronomy Textbooks

The first JWST Deep Field Image, showing large distant galaxies. The telescope's observations are revealing the previously unseen and are forcing a re-write of astronomy textbooks. Image Credit: NASA, ESA, CSA, STScI

When the James Webb Space Telescope was launched at the end of 2021, we expected stunning images and illuminating scientific results. So far, the powerful space telescope has lived up to our expectations. The JWST has shown us things about the early Universe we never anticipated.

Some of those results are forcing a rewrite of astronomy textbooks.

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Dwarf Galaxies Banished the Darkness and Lit Up the Early Universe

The JWST used gravitational lensing to search for the sources of light that triggered the Epoch of Reionization and brought darkness to an end. The white hazy blobs are galaxies in Pandora's Cluster, which acts as the gravitational lens. The red objects are the distant and ancient objects magnified by the lens, some of them warped into arcs. Many of them are early dwarf galaxies, some of them responsible for the Epoch of Reionization. Image Credit: NASA/ESA/CSA JWST

During the Universe’s Dark Ages, dense primordial gas absorbed and scattered light, prohibiting it from travelling. Only when the first stars and galaxies began to shine in energetic UV light did the Epoch of Reionization begin. The powerful UV light shone through the Universe and punched holes in the gas, allowing light to travel freely.

New observations with the James Webb Space Telescope reveal how it happened. The telescope shows that faint dwarf galaxies brought an end to the darkness.

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The JWST Solves the Mystery of Ancient Light

This image shows the galaxy EGSY8p7, a bright galaxy in the early Universe where light emission is seen from, among other things, excited hydrogen atoms — Lyman-alpha emission. The galaxy was identified in a field of young galaxies studied by Webb in the CEERS survey. In the bottom two panels, Webb’s high sensitivity picks out this distant galaxy along with its two companion galaxies, where previous observations saw only one larger galaxy in its place. This discovery of a cluster of interacting galaxies sheds light on the mystery of why the hydrogen emission from EGSY8p7, shrouded in neutral gas formed after the Big Bang, should be visible at all. Image Credit: ESA/Webb, NASA & CSA, S. Finkelstein (UT Austin), M. Bagley (UT Austin), R. Larson (UT Austin), A. Pagan (STScI), C. Witten, M. Zamani (ESA/Webb)

The very early Universe was a dark place. It was packed with light-blocking hydrogen and not much else. Only when the first stars switched on and began illuminating their surroundings with UV radiation did light begin its reign. That occurred during the Epoch of Reionization.

But before the Universe became well-lit, a specific and mysterious type of light pierced the darkness: Lyman-alpha emissions.

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James Webb is a GO for Cycle 2 Observations!

Artist conception of the James Webb Space Telescope. Credit: NASA GSFC/CIL/Adriana Manrique Gutierrez

The James Webb Space Telescope (JWST) has accomplished some amazing things during its first year of operations! In addition to taking the most detailed and breathtaking images ever of iconic celestial objects, Webb completed its first deep field campaign, turned its infrared optics on Mars and Jupiter, obtained spectra directly from an exoplanet’s atmosphere, blocked out the light of a star to reveal the debris disk orbiting it, detected its first exoplanet, and spotted some of the earliest galaxies in the Universe – those that existed at Cosmic Dawn.

Well, buckle up! The Space Telescope Science Institute (STScI) has just announced what Webb will be studying during its second year of operations – aka. Cycle 2! According to a recent STScI statement, approximately 5,000 hours of prime time and 1,215 hours of parallel time were awarded to General Observer (GO) programs. The programs allotted observation time range from studies of the Solar System and exoplanets to the interstellar and intergalactic medium, from supermassive black holes and quasars to the large-scale structure of the Universe.

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JWST Glimpses the Cosmic Dawn of the Universe

This still image shows the timeline running from the Big Bang on the right, towards the present on the left. In the middle is the Reionization Period where the initial bubbles caused the cosmic dawn. Credit: NASA SVS

The James Webb Space Telescope (JWST) continues to push the boundaries of astronomy and cosmology, the very job it was created for. First conceived during the 1990s, and with development commencing about a decade later, the purpose of this next-generation telescope is to pick up where Spitzer and the venerable Hubble Space Telescope (HST) left off – examining the infrared Universe and looking farther back in time than ever before. One of the chief objectives of Webb is to observe high-redshift (high-Z) galaxies that formed during Cosmic Dawn.

This period refers to the Epoch of Reionization, where the first galaxies emitted large amounts of ultraviolet (UV) photons that ionized the neutral hydrogen that made up the intergalactic medium (IGM), causing the Universe to become transparent. The best way to measure the level of star formation is the H-alpha emission line, which is visible in the mid-infrared spectrum for galaxies with high redshifts. Using data from the Mid-Infrared Instrument (MIRI), an international team of researchers was able to resolve the H-alpha line and observe galaxies with redshift values higher than seven (z>7) for the first time.

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JWST Shows How the Early Universe Was Furiously Forming Stars

This infrared image from NASA’s James Webb Space Telescope (JWST) was taken for the JWST Advanced Deep Extragalactic Survey, or JADES, program. It shows a portion of an area of the sky known as GOODS-South, which has been well studied by the Hubble Space Telescope and other observatories. More than 45,000 galaxies are visible here. Credits: NASA, ESA, CSA, Brant Robertson (UC Santa Cruz), Ben Johnson (CfA), Sandro Tacchella (Cambridge), Marcia Rieke (University of Arizona), Daniel Eisenstein (CfA). Image processing: Alyssa Pagan (STScI)

We can gaze out into regions in our neighbourhood of the Milky Way and find orgies of star birth. The closest region is in the Orion nebula, where astronomers have identified more than 700 young stars. They range from only 100,000 years—mere infancy for a star—to over a million years.

But we’re more than 13 billion years after the Big Bang now. What was star formation like way back when, when conditions in the Universe were so different?

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Hungry Black Hole was Already Feasting 800 Million Years After the Big Bang

Artist view of an active supermassive black hole. Credit: ESO/L. Calçada

Black holes swallow everything—including light—which explains why we can’t see them. But we can observe their immediate surroundings and learn about them. And when they’re on a feeding binge, their surroundings become even more luminous and observable.

This increased luminosity allowed astronomers to find a black hole that was feasting on material only 800 million years after the Universe began.

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Astronomers are Working on a 3D map of Cosmic Dawn

The HERA radio telescope consists of 350 dishes pointed upward to detect 21-centimeter emissions from the early Universe. Credit: HERA Partnership

The frontiers of astronomy are being pushed regularly these days thanks to next-generation telescopes and scientific collaborations. Even so, astronomers are still waiting to peel back the veil of the cosmic “Dark Ages,” which lasted from roughly 370,000 to 1 billion years after the Big Bang, where the Universe was shrouded with light-obscuring neutral hydrogen. The first stars and galaxies formed during this same period (ca. 100 to 500 million years), slowly dispelling the “darkness.” This period is known as the Epoch of Reionization, or as many astronomers call it: Cosmic Dawn.

By probing this period with advanced radio telescopes, astronomers will gain valuable insights into how the first galaxies formed and evolved. This is the purpose of the Hydrogen Epoch of Reionization Array (HERA), a radio telescope dedicated to observing the large-scale structure of the cosmos during and before the Epoch of Reionization located in the Karoo desert in South Africa. In a recent paper, the HERA Collaboration reports how it doubled the array’s sensitivity and how their observations will lead to the first 3D map of Cosmic Dawn.

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The James Webb Links Modern Green Pea Galaxies to Ancient Galaxies in the Cosmic Dawn

A trio of faint objects (circled) captured in the James Webb Space Telescope’s deep image of the galaxy cluster SMACS 0723 exhibit properties remarkably similar to rare, small galaxies called “green peas” found much closer to home. Image Credit: NASA, ESA, CSA, and STScI

When the James Webb Space Telescope lifted off from Earth on Christmas Day in 2021, it carried a lot of expectations with it. One of its scientific goals is to seek the light from the first galaxies in the Universe and to study how galaxies form and evolve.

A new paper shows that the JWST is doing just that and has found a link between the first galaxies and rare galaxies in our backyard that astronomers call “Green Pea” galaxies.

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