NASA Airborne Campaigns Focus on Climate Impacts in the Arctic

Flights are underway from Fairbanks, Alaska, with NASA’s C-130 Hercules aircraft to study the connection between retreating Arctic sea ice and climate change. 

Image Credit: NASA/Patrick Lynch

Over the past few decades, average global temperatures have been on the rise, and this warming is happening two to three times faster in the Arctic.

As the region’s summer comes to a close, NASA is hard at work studying how rising temperatures are affecting the Arctic.

NASA researchers this summer and fall are carrying out three Alaska-based airborne research campaigns aimed at measuring greenhouse gas concentrations near Earth’s surface, monitoring Alaskan glaciers, and collecting data on Arctic sea ice and clouds.

Observations from these NASA campaigns will give researchers a better understanding of how the Arctic is responding to rising temperatures.

Broken sea ice captured during an ARISE flight over the Arctic Ocean by one of the C-130 Hercules’s onboard cameras. 

Credit: NASA

The Arctic Radiation, IceBridge Sea and Ice Experiment (ARISE), is a new NASA airborne campaign to collect data on thinning sea ice and measure cloud and atmospheric properties in the Arctic.

The campaign was designed to address questions about the relationship between retreating sea ice and the Arctic climate.

Arctic sea ice reflects sunlight away from Earth, moderating warming in the region. Loss of sea ice means more heat from the sun is absorbed by the ocean surface, adding to Arctic warming.

In addition, the larger amount of open water leads to more moisture in the air, which affects the formation of clouds that have their own effect on warming, either enhancing or reducing it.

Changes in more than 130 Alaskan glaciers are being surveyed by scientists at the University of Alaska-Fairbanks in a DHC-3 Otter as part of NASA’s multi-year Operation IceBridge.

Image Credit: Chris Larsen, University of Alaska-Fairbanks

“ARISE will link clouds and sea ice in a way that improves our computer models of the Arctic,” said Tom Wagner, cryospheric sciences program manager at NASA Headquarters in Washington.

“Our goal is to better understand both the causes of Arctic ice loss and the connections to the overall Earth system.”

The ARISE campaign, using NASA’s C-130 Hercules aircraft from Wallops Flight Facility in Virginia, had its first science flight on Sept. 4 and has already carried out several surveys of sea ice and cloud conditions. The campaign is based in Fairbanks, Alaska.

“We are off to a great start collecting a timely and unique dataset to help better understand the potential influence of clouds on the Arctic climate as sea ice conditions change,” said William Smith, ARISE principal investigator at NASA’s Langley Research Center in Hampton, Virginia.

Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE), is a five-year airborne research campaign that uses instruments aboard NASA aircraft to measure air and surface conditions and concentrations of gases like carbon dioxide, carbon monoxide and methane.

Using NASA’s C-23 Sherpa aircraft, CARVE flies approximately two weeks per month from May to November.

Now that the mission is in its fourth year, researchers are building a detailed picture of how the land and atmosphere interact in the Arctic.

In high-latitude areas like Alaska, frozen ground known as permafrost can trap large amounts of carbon dioxide and methane produced by layers of decayed plant and animal matter.

As permafrost temperatures have been increasing faster than air temperatures in the Arctic, scientists have questioned whether these heat-trapping gases could be released into the atmosphere, increasing their global concentrations.

“The exchange of carbon between the land and the atmosphere is very important, but uncertain,” said Charles Miller, a scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, and principal investigator of CARVE.

ESO ALMA: Violent origins of disc galaxies probed

Each of the colourful objects in this image illustrates one of 30 merging galaxies. 

The contours in the individual galaxies indicate the dispersion of carbon monoxide while the color represents the motion of gas. 

Gas that is moving away from us appears red while the blue colour shows gas that is approaching. 

The contours together with the transition from red to blue indicate a gaseous disc that is rotating about the center of the galaxy. Credit: ALMA (ESO /NAOJ /NRAO) /SMA /CARMA /IRAM /J. Ueda et al.

For decades scientists have believed that galaxy mergers usually result in the formation of elliptical galaxies.

Now, for the the first time, researchers using the Atacama Large Millimeter/sub-millimeter Array (ALMA) and a host of other radio telescopes have found direct evidence that merging galaxies can instead form disc galaxies, and that this outcome is in fact quite common.

This surprising result could explain why there are so many spiral galaxies like the Milky Way in the Universe.

An international research group led by Junko Ueda, a Japan Society for the Promotion of Science postdoctoral fellow, has made surprising observations that most galaxy collisions in the nearby Universe, within 40 million light-years from Earth, result in so-called disc galaxies.

Disc galaxies, including spiral galaxies like the Milky Way and lenticular galaxies, are defined by pancake-shaped regions of dust and gas, and are distinct from the category of elliptical galaxies.

It has, for some time, been widely accepted that merging disc galaxies would eventually form an elliptically shaped galaxy.

During these violent interactions the galaxies do not only gain mass as they merge or cannibalise each-other, but they are also changing their shape throughout cosmic time, and therefore changing type along the way.

Computer simulations from the 1970s predicted that mergers between two comparable disc galaxies would result in an elliptical galaxy.

The simulations predict that most galaxies today are elliptical, clashing with observations that over 70% of galaxies are in fact disc galaxies.

However, more recent simulations have suggested that collisions could also form disc galaxies.


This artist’s impression shows the merger between two galaxies leading to the formation of a disc galaxy. 

Upon merging, the shape of the galaxies is disturbed by their mutual gravitational interaction and results in a galaxy with a disc structure.

Gas that is moving away from us appears red while the blue colour shows gas that is approaching. 

The contours together with the transition from red to blue indicate a gaseous disc that is rotating about the centre of the galaxy.

The movie shows the collision of two disc galaxies, but the actual shape of galaxies prior to the collision in this study is not known. Credit: NAOJ

To identify the final shapes of galaxies after mergers observationally, the group studied the distribution of gas in 37 galaxies that are in their final stages of merging.

The Atacama Large Millimeter/sub-millimeter Array (ALMA) and several other radio telescopes were used to observe emission from carbon monoxide (CO), an indicator of molecular gas.

The team's research is the largest study of molecular gas in galaxies to date and provides unique insight into how the Milky Way might have formed.

Their study revealed that almost all of the mergers show pancake-shaped areas of molecular gas, and hence are disc galaxies in the making.

Ueda explains: "For the first time there is observational evidence for merging galaxies that could result in disc galaxies. This is a large and unexpected step towards understanding the mystery of the birth of disc galaxies."

Nonetheless, there is a lot more to discover. Ueda added: "We have to start focusing on the formation of stars in these gas discs."

"Furthermore, we need to look farther out in the more distant Universe. We know that the majority of galaxies in the more distant Universe also have discs."

"We however do not yet know whether galaxy mergers are also responsible for these, or whether they are formed by cold gas gradually falling into the galaxy."

"Maybe we have found a general mechanism that applies throughout the history of the Universe."

More information: Research paper on Astro-Ph: arxiv.org/abs/1407.6873

Carbon monoxide predicts 'red and dead' future of gas guzzler galaxy

This image shows radio waves emitted from ALESS65 as observed by the Australia Telescope Compact Array (ATCA). 

Credit: Huynh et al.

Astronomers have studied the carbon monoxide in a galaxy over 12 billion light years from Earth and discovered that it's running out of gas, quite literally, and headed for a 'red and dead' future.

The galaxy, known as ALESS65, was observed by the Atacama Large Millimeter Array (ALMA) in 2011 and is one of less than 20 known distant galaxies to contain carbon monoxide.

Dr Minh Huynh from The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR) led the team on their search for galactic carbon monoxide in work published today in the Monthly Notices of the Royal Astronomical Society.

"We're familiar with carbon monoxide here on Earth as the deadly gas that can cause suffocation, but in galaxies it plays an important role in the lifecycle of stars," said Huynh.

"Out of the galaxies that we know contain carbon monoxide, less than 20 are as far away from Earth as ALESS65. Out of the billions of galaxies out there, the detections are very rare!"

Huynh, who grew up in Perth, said that at first astronomers didn't think there could be massive 'red and dead' galaxies in the distant Universe, so studying galaxies heading towards that fate is important to solve the puzzle of their existence.

This is NGC5044, a "red and dead" galaxy like ALESS65 will become in about 25 million years. 

NB:The X-Rays are shown in blue and the visible light is shown in yellow. 

Credit: X-ray: NASA /CXC /Stanford Univ /N.Werner et al; Optical: DSS

Using the Australia Telescope Compact Array (ATCA) radio telescope in NSW, Australia, Huynh and the team worked out how much carbon monoxide they could see in ALESS65 and extrapolated that out into how much fuel the galaxy has left, how much gas it has.

"All galaxies have a certain amount of fuel to make new stars," said Huynh.

"Our galaxy, the Milky Way, has about five billion years before it runs out of fuel and becomes 'red and dead', but ALESS65 is a gas guzzler and only has 10s of millions of years left, very fast in astronomical terms."

The Atacama Compact Array (ACA) forming part of the ALMA observatory. 

Credit: ALMA, ESO

The team also combined their observations of the galaxy with the original data from ALMA to work out how similar ALESS65 is to galaxies nearer to Earth.

Arp220, a nearby ‘Ultraluminous Infrared Galaxy’ similar to what ALESS65 would look like if it were closer to Earth. 

Credit: NASA, ESA, and the Hubble Team

"We were able to work out the strength of the UV radiation in ALESS65; it's similar to some 'starbursting' galaxies in the local universe, but the stars in ALESS65 are forming in much larger areas when compared to local galaxies," said Huynh.

The team will now turn their attentions to the search for carbon monoxide in another galaxy near to ALESS65, named ALESS61.

"Finding and studying carbon monoxide in more galaxies will tell us even more about how stars formed in the early days of the Universe and help solve the mystery of far away 'red and dead' galaxies" said Huynh.

More information: "Detection of molecular gas in an ALMA [CII]-identified Submillimetre Galaxy at z=4.44" Huynh et al. Monthly Notices of the Royal Astronomical Society, Published 9th of July 2014. mnrasl.oxfordjournals.org/look… 0.1093/mnrasl/slu077 . On Arxiv: arxiv.org/abs/1407.0463

New Method: Measuring Super-Massive Black Holes

Understanding the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby galaxies is one of the most active research areas in astrophysics.

In a letter to Nature, an international team of astronomers, including Marc Sarzi from the University of Hertfordshire, report the exciting discovery of a new way to measure the mass of super-massive black holes in galaxies.

By measuring the speed with which carbon monoxide molecules orbit around such black holes, this new research opens the possibility of making these measurements in many more galaxies than ever before.

Supermassive black holes and galaxies
A black hole is an object so dense that its gravity prevents anything, including light, from escaping.

Supermassive black holes can be as much as a million to a billion times more massive than our Sun, and it is believed that most, if not all galaxies including the Milky Way, contain supermassive black holes at their centres - suggesting that the evolution of black holes and galaxies is very tightly linked.

Understanding the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby galaxies is one of the most active research areas in astrophysics.

Intriguing link
Marc Sarzi, from the University of Hertfordshire's Centre for Astrophysics Research, said: "There is an intriguing link between the mass of supermassive black holes and the mass of their host galaxies, but this is based only on quite a small number of estimates.

Until now only three methods were used to measure the mass of supermassive black holes and these only work on relatively nearby galaxies.

With this new technique, we have been able to show that we can measure black hole masses much further out in the universe, which will help understanding the role that supermassive black holes played during the formation of galaxies."

Super-sharp telescope images
Tim Davis, lead author of the paper, from ESA's European Southern Observatory (ESO), commented:

"We observed carbon monoxide molecules in the galaxy we were monitoring using the Combined Array for Research in Millimeter-wave Astronomy (CARMA) telescope.

With its super-sharp images we were able to zoom right into the centre of the galaxy and observe the gas whizzing around the black hole. This gas moves at a speed which is determined by the black-hole's mass, and the distance from it. By measuring the velocity of the gas at each position, we can measure the mass of the black hole."

The CARMA observations were rather challenging, but the new ALMA (Atacama Large Millimeter/submillimeter Array) telescope currently being built in Chile will allow this new technique to be applied more routinely to hundreds of galaxies in the nearby Universe.