The first JWST Deep Field Image, showing large distant galaxies. Credit: NASA, ESA, CSA, STScI
There’s a common pattern in science. We develop some new process or tool that allows us to gather all kinds of data we’ve never had before, the data threatens to overturn all we’ve assumed about some long-established theory, and then the dust settles. Unfortunately, the early stage of this process generates a lot of sensationalism in the press. Early results from the JWST are a good example of this.
75 hours of observing time allows for this 'amateur' view of the Antennae galaxies in the constellation Corvus. Look closely to see the myriad of distant background galaxies that show up in the image, as well. Credit and copyright: Rolf Wahl Olsen.
You might think the image above of the famous Antenna Galaxies was taken by a large ground-based or even a space telescope. Think again. Amateur astronomer Rolf Wahl Olsen from New Zealand compiled a total of 75 hours of observing time to create this ultra-deep view.
“To obtain a unique deep view of the faint tidal streams and numerous distant background galaxies I gathered 75 hours on this target during 38 nights from January to June 2014,” Rolf said via email. “At times it was rather frustrating because clouds kept interrupting my sessions.”
But he persisted, and the results are stunning.
He used his new 12.5″ f/4 Serrurier Truss Newtonian telescope, which he said gathers approximately 156% the amount of light over his old 10″ f/5 telescope.
Rolf even has put together comparison shots from the Hubble Space Telescope and the Very Large Telescope of the same field of view:
Comparison images from the Hubble Space Telescope and the Very Large Telescope, compared with the 75-hour ultra-deep image by Rolf Wahl Olsen. Credit and copyright: Rolf Wahl Olsen.
And if you look even closer you can see an incredible field of distant background galaxies. “Apart from the Antennae itself, what I like most about this scene is the incredible number of distant background galaxies,” Rolf told Universe Today. “This area in Corvus seems very rich indeed. The full resolution image is worth having a look at just to see all these faint galaxies littering the background. There are many beautiful interacting pairs and groups which would be fantastic targets in themselves if they were only closer.”
Here’s a collage of some of the background galaxies that Rolf compiled: A gallery of distant background galaxies in the same field of view as the Antenna Galaxies. Credit and copyright: Rolf Wahl Olsen.
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ALMA's first light: a view of the Antennae Galaxies. Credit: ESO
There’s a new telescope in town that just opened up for business. It’s the long awaited ALMA, the Atacama Large Millimeter/submillimeter Array. Although it is still under construction, the science teams have released the first “early science” image, showing a pair of interacting galaxies called the Antenna Galaxies. ALMA’s view reveals a part of the Universe that just can’t be seen by visible-light and infrared telescopes. “From the formation of the first galaxies, stars, and planets to the merging of the first complex molecules, the science of ALMA is a vast spectrum of investigation,” said Tania Burchell, the ALMA Public Information Officer at the National Radio Astronomy Observatory, on today’s 365 Days of Astronomy podcast.
A composite image combining images of the Antenna Galaxies from ALMA and the Hubble Space Telescope. Credit: ESO, Space Science Institute
Currently, about one third of ALMA’s eventual 66 radio antennas are built and operational. The antennas are positioned just 125 meters apart on the Chajnantor plateau in northern Chile. This extremely dry and high desert sits over 5,000 meters (16,500) feet above sea level. This puts ALMA higher than any other telescope array on Earth. At this elevation, the temperatures hover around freezing all year round, and the air pressure is half that at sea level. Cold temperatures combined with little air is perfect for telescopes like ALMA.
“Even in this very early phase ALMA already outperforms all other submillimetre arrays,” said Tim de Zeeuw, Director General of ESO, the European partner in ALMA. “Reaching this milestone is a tribute to the impressive efforts of the many scientists and engineers in the ALMA partner regions around the world who made it possible.”
Historically, collecting, focusing, and imaging millimeter and submillimeter waves has been very tricky, Burchell said.
“These waves are so large that mirrors cannot focus them, and their frequencies are too high for off-the-shelf receiver technologies to process,” said said. “The warmth of a telescope’s own electronics is enough to ruin the weak cosmic mm signals that, by the time they reach us, sputter in at about a billionth of a billionth the power of a cell phone call. And as an added torment, humidity itself broadcasts at these frequencies, turning most skies into a glare of millemeter/submillimeter light.”
But ALMA is radically different from visible-light and infrared telescopes. It is an array of linked antennas acting as a single giant telescope, and it detects much longer wavelengths than those of visible light. Its images therefore look quite unlike more familiar pictures of the cosmos.
Compare images of the Antenna Galaxies, from ALMA and the Very Large Telescope:
A comparison of the views of the Antenna Galaxies, from ALMA and the VLT. Credit: ESO.
ALMA’s view reveals the clouds of dense cold gas from which new stars form. This is the best submillimeter-wavelength image ever made of the Antennae Galaxies.
Massive concentrations of gas are found not only in the hearts of the two galaxies but also in the chaotic region where they are colliding. Here, the total amount of gas is billions of times the mass of our Sun — a rich reservoir of material for future generations of stars. Observations like these open a new window on the submillimetre Universe and will be vital in helping us understand how galaxy collisions can trigger the birth of new stars. This is just one example of how ALMA reveals parts of the Universe that cannot be seen with visible-light and infrared telescopes.
