Returning to New Zealand: SOFIA Travels to Christchurch for a Seventh and Final Time

By Maggie McAdam

After a two-year hiatus, SOFIA has returned to Christchurch, New Zealand, for a long deployment. About once a year, SOFIA temporarily moves its operating home to better observe celestial objects in the Southern Hemisphere.

SOFIA at Christchurch International Airport
SOFIA taxiing on the ramp at Christchurch International Airport in 2017. Image Credit: NASA/SOFIA/Waynne Williams

There is always a high demand from the SOFIA scientific community to observe the southern skies, and SOFIA has been working to meet those needs. This year, we already deployed once to Santiago, Chile, for a quick, two-week deployment to observe the Large Magellanic Cloud. Now SOFIA is heading back to New Zealand for the seventh and final time.

“We are thrilled to be returning to Christchurch to continue to study and discover the infrared universe,” said Naseem Rangwala, the SOFIA project scientist.

SOFIA has made 12 deployments over its operational lifetime, generally leaving Palmdale, California, to observe celestial objects and phenomena not visible from its home skies. We observed occultations in Florida and New Zealand, as well as atomic oxygen in Earth’s atmosphere, stellar feedback, and magnetic fields from German soil.

Christchurch is often SOFIA’s home-away-from-home when deploying overseas. This time, SOFIA plans to conduct 32 flights to observe a wide range of celestial objects and phenomena, like cosmic magnetic fields, stellar feedback, and cosmic rays, using two instruments, HAWC+ and GREAT.

Probing the Magnetic Universe

Milky Way galactic center, looking like a band of red clouds against a starry background.
While in New Zealand, SOFIA will observe magnetic fields in our galaxy, the Milky Way, pictured here from a previous study with another SOFIA instrument. Image credit: NASA/SOFIA/JPL-Caltech/ESA/Herschel.

Sticking relatively close to our cosmic home, SOFIA will start by investigating our galaxy, the Milky Way. A team of researchers is mapping the magnetic fields within the Milky Way’s central regions. These data will complement a previous Legacy Program that made mid-infrared images of the Milky Way. This work is similar to other cosmic magnetic field studies that map the shape and strength of this invisible force in other galaxies. SOFIA can detect cosmic magnetic fields on many scales, including star formation scales, especially along filaments.

SOFIA will also be looking at magnetic fields in filaments of material in our galaxy. These filaments are thread-like structures full of cold gas and dust. Most stars form in these dark rivers of material. A team of scientists will be investigating how magnetic fields play a role in star formation in filaments.

Stars Blowing Bubbles and a Barometer for Cosmic Rays

Deployment crew and staff stand in front of the SOFIA aircraft, all wearing neon yellow high-vis vests and jackets.
SOFIA in Christchurch, New Zealand, during its 2019 deployment with the staff and crew of the observatory. Image credit: NASA/Waynne Williams.

After HAWC+ finishes up probing the magnetic universe, SOFIA’s operations team will swap the instrument for the German PI-led GREAT instrument. GREAT does a wide variety of studies including looking at stellar feedback – how some stars can affect the regions around them. Young massive stars create huge winds that blow out into the surrounding dusty material, sometimes blowing celestial bubbles. As they do this, the stellar winds plow into the material and sometimes can trigger or quench star formation. Scientists want to understand when and why star formation is turned on or off.

GREAT, like the radio in your car, can be tuned to be sensitive to specific signals. During the New Zealand deployment, it will be set to register hydride molecules. These molecules were some of the first types that formed in our universe, and, even now, they are sometimes created in other environments. When scientists detect hydrides, they can use them as sensitive barometers for the presence of cosmic rays, high energy particles that travel close to the speed of light.

Hydride molecules form in very specific circumstances, and, usually, scientists can determine their production rate. At the same time, these molecules are quite delicate and can easily be destroyed by passing cosmic rays. Understanding the balance between their production and destruction can provide clues to the abundance of cosmic rays.

Scientists have measured the cosmic rays produced by our Sun and understand them very well, but do not fully understand cosmic rays that originate from outside our solar system. Using hydride molecules, researchers will investigate how abundant cosmic rays are in environments outside our solar system.

A Strong Finish

Arc-shaped patch with gold border and SOFIA text in gold with the telescope mirror in place of the O. The patch reads "New Zealand 2022, NASA, DLR, USRA, DSI" and shows SOFIA flying over New Zealand with the Milky Way and the fours stars of the Southern Cross constellation in the background sky.
2022 Deployment patch graphic. Image credit: NASA/SOFIA/Cheryse Triano.

Many of the key celestial objects for astronomers, like the center of the Milky Way, are either visible only from the Southern Hemisphere or more easily observed from these latitudes. Three years after SOFIA achieved first light in 2010, the observatory made its first trip to New Zealand. Now, nine years later and with six previous trips to Christchurch, this will be SOFIA’s last international deployment.

NASA and DLR recently announced the conclusion of the SOFIA mission. SOFIA will operate for the rest of fiscal year 2022, before entering an orderly shutdown process on October 1, 2022.

“We are committed to delivering a strong finish for this unique astrophysics mission, from a place of strength and pride, by giving our scientific community as much data as possible from the Southern Hemisphere,” Dr. Rangwala said. Moving forward, SOFIA’s data will be available in NASA’s public archives for astronomers worldwide to use.

SOFIA is a joint project of NASA and the German Space Agency at DLR. DLR provides the telescope, scheduled aircraft maintenance, and other support for the mission. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California.

Are Magnetic Fields Moving the Clouds in Cygnus-X?

by Anashe Bandari

Hidden behind a dark band of dust known as the Great Rift, the Cygnus-X star formation region is more than a bit of a mystery. Astronomers haven’t quite figured out what the molecular clouds in Cygnus-X are doing, and why, but observations from the Stratospheric Observatory for Infrared Astronomy (SOFIA) may help.

These mysteries relate to the fact that Cygnus-X is a difficult region to study. Two of its clouds – DR21 and W75N – clearly have separate gas velocities, but which cloud is in front of the other, and whether or not the two clouds are colliding, are open questions. Dan Clemens, an astronomer at Boston University, is the principal investigator on a project using SOFIA to examine Cygnus-X and the effects of magnetic fields on its clouds and cloud filaments. Details of these studies were presented at the June 2022 meeting of the American Astronomical Society.

Cygnus-X northeast region with segments showing the magnetic field orientations and curves highlighting filaments and sub-filaments.
Cygnus-X northeast region. Background image was constructed from Herschel SPIRE 250um in red, Herschel PACS 70um in green, and Spitzer MIPS 24um in blue. Red polygon indicates region surveyed for near-infrared, H-band (1.6um) stellar polarizations. Cyan segments indicate the magnetic field orientations derived from those NIR polarizations. Dashed white curves highlight filaments and sub-filaments cataloged by Hennemann et al. (2012) and new filaments and subfilaments from this study. The green polygon shows the DR21 Ridge region surveyed using SOFIA HAWC+ E-band (214um) polarization and the inscribed smaller magenta polygon shows the corresponding HAWC+ A-band (52um) polarization surveyed region. Credit: Herschel/Spitzer/SOFIA/Hennemann et al./Clemens et al.

“You can think of it as a pasta bowl with all these threads going in,” said Clemens. “Which pasta is in front of which pasta? Are there separate piles of pasta, or are they interacting piles of pasta that cause stars to form?”

On top of this, the presence of magnetic fields adds further complexity. What these magnetic fields are doing – whether they are passive participants in the clouds’ dynamics or helping to direct mass flows – is a question the SOFIA data may help answer by looking at small-scale filaments within the clouds.

Using SOFIA’s High-resolution Airborne Wideband Camera Plus (HAWC+), Clemens and his team zoomed in on Cygnus-X to look at the polarizations of the filaments at far-infrared wavelengths. These polarizations indicate the directions of the small-scale magnetic fields in the region, which the researchers use to determine the role the fields are playing.

“We want to ascertain the nature of the magnetic fields along these filaments, where they begin, and where they end,” Clemens said.  “This will help test our best star formation models and notions.”

Most modern theories of star formation hint that magnetic fields may be channeling gas flows within molecular clouds toward a central hub, where massive star formation occurs. The SOFIA observations will reveal the magnetic fields in filaments within the clouds, helping to verify the idea that fine, weak magnetic fields can control how stars form.

According to the team’s analysis, there appear to be four distinct layers of gas and dust between us and the northern region of Cygnus-X. Whether or not these layers are interacting will affect their understanding of SOFIA’s magnetic field data. As such, Clemens and his collaborators will need to determine which cloud is in front of the other, and if they are going to collide, before the SOFIA data – and supporting wider-field, ground-based, near-infrared data – describing the magnetic fields can be effectively interpreted.

SOFIA is a joint project of NASA and the German Space Agency at DLR. DLR provides the telescope, scheduled aircraft maintenance, and other support for the mission. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California. SOFIA achieved full operational capability in 2014, and the mission will conclude no later than Sept. 30, 2022. SOFIA will continue its regular operations until then, including science flights and a deployment to New Zealand this summer.

Small Molecules Have Big Impacts in Interstellar Clouds

by Anashe Bandari

“One of the key goals, when you think about modern astronomy, considers the life cycle of molecular material,” said Arshia Jacob, an astronomer at Johns Hopkins University. Diffuse atomic gas becomes dense molecular gas, which ultimately forms stars and stellar systems, and continues to evolve over time. Though astronomers understand much of this process, there are a lot of missing pieces.

Jacob is the lead author on a recent paper characterizing the interstellar medium in the Milky Way using SOFIA, the Stratospheric Observatory for Infrared Astronomy, to fill in some of these missing pieces. By studying six hydrides, which are molecules or molecular ions in which one or more hydrogen atoms are bound to a heavier atom through shared electron pairs, Jacob and her collaborators hope to better understand how molecular clouds form and evolve.

Green and red swirls of nebulae are seen over a field of bright blue stars with W3 glowing white. Two spectra are laid over the background image, one green, one red.
W3, one of the 25 Milky Way regions the HyGAL project will study, is seen as the glowing white area in the upper right of this image of the Heart and Soul Nebulae, taken by NASA’s Wide-field Infrared Survey Explorer (WISE). SOFIA looked at the abundances of six hydride molecules in W3, the spectra of two of which are shown in the box at left. Image credit: Nebulae: NASA/JPL-Caltech/UCLA; Spectra: Jacob et al.

Hydrides are useful to astronomers because they are very sensitive tracers of different phases of the interstellar medium, and their chemistry is relatively straightforward. Moreover, hydride observations provide measurements of the amount of material present.

The multi-investigator SOFIA project Hydrides in the Galaxy (HyGAL) uses a diverse selection of hydride molecules, allowing different processes to be monitored while complementing other observations. For example, one of the hydrides studied, argonium, can only form in regions that are almost purely atomic gas, so detecting argonium is indicative of a low molecular content in its surrounding environment. Other hydride molecules can indicate the presence of dense gas, intense cosmic radiation, turbulence, and more.

“Hydrides are small, but we can understand so much from them. Small molecules, big impact,” Jacob said.

In the first stage of the project, the group compared the hydride abundances in three regions of the Milky Way: two star-forming regions, W3(OH) and W3 IRS5, and a young stellar object, NGC 7538 IRS1. Though the average properties of these first three sources are similar, the full HyGAL project plans to study a total of 25 regions. With the remaining 22 sources covering distances from the inner galaxy all the way to the outer galaxy, they expect vastly different results.

“The sources are very different: Some of them are older, some have more chemical enrichment, some are younger and still forming stars,” Jacob said. “All of these will affect the nature of molecules that are formed, like their abundances, for example.”

Moving away from the galactic center, the transitions from atomic to molecular gas change, and the cosmic ray ionization rates vary vastly, which will result in differences in the ratios of molecules present and other properties. This will help astronomers understand the diversity of environments within the Milky Way.

“Imagine you’re moving into a cloud. At each stage, you’re seeing different molecules, reflecting changes in the cloud properties as it gets denser,” Jacob said. “Through this project, we’re filling in the properties of this transition.”

Currently, there have only been a handful of bright sources emitting a broad range of radiation that have been studied in this way, all concentrated in the inner galaxy. The SOFIA data will more than double the existing data, providing additional answers about the structure, dynamics, and chemistry of these clouds and where the dense material comes from.

SOFIA is the only facility presently capable of accessing the frequency range necessary for these observations at the required resolution. The German REceiver Astronomy at Terahertz Frequencies (GREAT) instrument aboard SOFIA allows five frequencies to be monitored simultaneously, each tuned to five of the six hydrides in question to determine the makeup of the cloud sources. These are complemented by studies at radio wavelengths with observatories such as the Karl G. Jansky Very Large Array near Socorro, New Mexico.

“The idea is to give us not only information about the sources themselves, but also information about the different spiral arms they cross, making this truly a study over galactic scales,” Jacob said.

SOFIA is a joint project of NASA and the German Space Agency at DLR. DLR provides the telescope, scheduled aircraft maintenance, and other support for the mission. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California. SOFIA achieved full operational capability in 2014, and the mission will conclude no later than Sept. 30, 2022. SOFIA will continue its regular operations until then, including science flights and a deployment to New Zealand this summer.

SOFIA Watches a Binary Star System’s Eclipse

by Anashe Bandari

With its observations of a special pair of stars at a special moment in their lives, the Stratospheric Observatory for Infrared Astronomy (SOFIA) is shedding new light on stardust.

Over an interval of 387 days, a giant star in the constellation Aquarius periodically has a dramatic change in its brightness. This is because the star falls into a category called Mira variables, which pulsate over long periods and surround themselves in a shell of dust.

But this isn’t just any Mira variable. The star is one of two in a binary star system known as R Aquarii, where it has a companion white dwarf. The two orbit one another, and the white dwarf crosses in front of the Mira variable every 43.6 years, causing an eclipse from the perspective of a viewer on Earth.

This composite image of R Aquarii resembles a ring of fire over a black field, with a glowing purple “S” flowing through it. Near the center of the image, in the middle of the ring and the “S” wave, is a twinkle of bright white, which is the Mira variable in R Aquarii.
This composite image of R Aquarii resembles a ring of fire over a black field, with a glowing purple “S” flowing through it. Near the center of the image, in the middle of the ring and the “S” wave, is a twinkle of bright white, which is the Mira variable in R Aquarii. The white dwarf is very faint and contributes very little to the optical emission. However, the purple wave is the result of a jet that is powered by the white dwarf accreting dust produced by the Mira variable. The smokey red circles are evidence of explosive events that occurred several hundred years ago. Overlain atop the composite image of R Aquarii is a set of five plots indicating the energy emitted by the system. SOFIA acquired four of the data sets, while the strong purple plot is data from the Infrared Space Observatory from 1996, when R Aquarii’s emission was strongest. The strength also depends on the phase of the binary star system’s eclipse, so it does not increase each successive year, exactly: the flux fell between 2018 and 2019. Credit: NASA/CSC/SAO/STScI/Palomar Observatory/DSS/NSF/NRAO/VLA/LCO/IMACS/MMTF/Sankrit et al.

There’s another thing that’s special about R Aquarii: The periastron, or the point in the orbit where the two stars are closest to each other, happens during the eclipse. This means that as the eclipse occurs – and the pair gets dimmer and dimmer, overall – the white dwarf and the Mira variable get closer and closer together. The white dwarf accretes more and more of the dust surrounding the Mira variable, and, because of this optimal geometry, we get to watch this process occur.

Since 2016, SOFIA, a joint project of NASA and the German Space Agency at DLR, has been monitoring the onset of the eclipse, which started in 2018, with periastron expected to occur in 2023. The flow of dust can be inferred at mid-infrared wavelengths, and SOFIA’s infrared camera, FORCAST, has just the right angular resolution to watch.

By combining what they know about the system – the distance between the two stars, the fact that an eclipse is ongoing, and predictions of how much dust there is – astronomers can figure out the balance between the amount of dust escaping the Mira variable and how much is being accreted by the white dwarf. These are “both very big questions,” said Ravi Sankrit, an astronomer at the Space Telescope Science Institute in Baltimore and first author on a recent paper about SOFIA’s 2018 and 2019 observations of R Aquarii.

“It’s an opportunity to see it in a unique way, because the material that’s being accreted isn’t obscured by the Mira, it’s right out in front,” added Steven Goldman, a scientist with Universities Space Research Association, based at NASA’s Ames Research Center in California’s Silicon Valley. Goldman is a co-author on the paper, which looks at how the onset of the eclipse is beginning to affect the dust surrounding the system.

Since the two stars move from being very far apart to very close to one another, their dust is constantly changing. Continued mid-infrared monitoring is required to fully understand how the dust is affected by the stars’ orbit.

“Binarity, winds, jet formation, mass loss, and accretion are fundamental astrophysics,” Sankrit said. “So, the real excitement here is that you’re getting something that is on a human timescale probing very fundamental aspects of astrophysics.”

The physics Sankrit, Goldman, and their team are uncovering is applicable to more than just R Aquarii. There are hundreds of other similar binaries, and those are just the ones we know of. These other binary systems are likely experiencing the same phenomenon but aren’t oriented correctly for us to be able to see their periastron and the changes in their surrounding dust.

SOFIA is a joint project of NASA and the German Space Agency at DLR. DLR provides the telescope, scheduled aircraft maintenance, and other support for the mission. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California. SOFIA achieved full operational capability in 2014, and the mission will conclude no later than Sept. 30, 2022. SOFIA will continue its regular operations until then, including science flights and a deployment to New Zealand this summer.

Looking to Jupiter, a Jovial Surprise

by Anashe Bandari

During flights in August 2018 and July 2019, planetary scientists used the Stratospheric Observatory for Infrared Astronomy (SOFIA), a joint project of NASA and the German Space Agency at DLR, to study the atmospheric circulation on Jupiter – for the first time during the planet’s northern winter.

Two images of Jupiter side by side. On the left is Jupiter with its red spot and swirling brown, beige, and white cloud bands. On the right is Jupiter in the same position but with only a few bands showing yellow and dark orange against an orange background, with no red spot visible.
Left: Optical image of Jupiter taken by the Hubble Space Telescope. Right: SOFIA image of Jupiter demonstrating the variation in its brightness temperature with latitude. The two images show Jupiter in approximately the same orientation. Image credit: Left: NASA/ESA; Right: NASA/SOFIA/de Pater et al., 2021

To do so, they looked at hydrogen.

Hydrogen molecules – H2 – can be arranged in two different ways, known as parahydrogen and orthohydrogen. The two orientations have distinct energies, so determining the ratio of parahydrogen to orthohydrogen can tell astronomers about the overall temperature.

The researchers looked at the concentration of parahydrogen and orthohydrogen at altitudes just above Jupiter’s main cloud deck. They discovered that, around the equator, warm gas is rising into the atmosphere. At the north and south poles, however, the opposite is occurring: Cold gas from the higher, cooler levels of the atmosphere is traveling downward.

“This gives a sense of the general circulation: rising at the equator, sinking near the poles,” said Imke de Pater, lead author on a recent paper in the Planetary Science Journal describing the observations.

Jupiter’s atmosphere had been looked at through the lens of hydrogen before – by SOFIA in 2014, and by NASA’s Voyager 1 and 2 in 1979 – but only during the northern Jovian summer. The current observations were the first ever taken during Jupiter’s northern winter, about half a Jovian year after the 2014 SOFIA studies. This comparison illustrated how Jupiter’s poles change with the seasons, showing that its far north remains cooler than its far south, regardless of time of year.

Jupiter’s northern and southern hemispheres are known to have an asymmetric aerosol distribution, so this temperature imbalance between its two poles is likely an effect of its asymmetry.

In studying Jupiter, de Pater and her colleagues also saw four other objects that had entered SOFIA’s field of view and the data collected: Jupiter’s four largest moons, known collectively as its Galilean satellites – Io, Europa, Ganymede, and Callisto.

“We were surprised that we actually captured all four satellites, and could determine their brightness temperature,” de Pater said.

Thanks to this pleasant surprise, the group could clearly see how the moons’ temperatures decrease with depth in their subsurface layers. These temperature changes can eventually be used to determine the composition, density, and other properties inside the satellites.

The satellites all have unique characteristics – ranging from water ice on Europa, to heavy craters on the ancient Callisto, to extreme volcanic activity on Io – making their material makeup particularly interesting to investigate.

Jupiter and its moons are too bright to be observed by the long wavelength channels on the James Webb Space Telescope as they can saturate the instrument, and they cannot be measured from the ground due to Earth’s atmosphere blocking a large amount of mid-infrared radiation. SOFIA’s unique access to the mid-infrared, therefore, enables these measurements and provides critical information about Jupiter and its moons.

SOFIA is a joint project of NASA and the German Space Agency at DLR. DLR provides the telescope, scheduled aircraft maintenance, and other support for the mission. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California.

Make No Bones About It: SOFIA Maps the First Magnetic Fields of a Galactic Bone in Their Entirety

by Anashe Bandari

Most stars in spiral galaxies form within the galaxy’s arms. Building the “skeletons” of these galaxies are galactic bones, long filaments that outline the densest parts of the arms.

A long horizontal narrow orange cloud on a background of soupy brown and gray clouds. Magnetic field streamlines are laid over the orange cloud like stripes on a tiger's back.
A map shows the direction of magnetic fields in the G47 bone overlain atop an image of the G47 filament as seen by the Herschel Space Observatory. The red and yellow areas are high-density regions of dust and gas. Credit: G47: ESA/Herschel/PACS/SPIRE/Ke Wang et al. 2015; Polarization map: Stephens et al., 2022

At the largest scales, the magnetic fields of a galaxy follow its spiral arms. Fields in the bones were accordingly believed to be aligned with respect to the bone, but research from the Stratospheric Observatory for Infrared Astronomy (SOFIA), a joint project of NASA and the German Space Agency at DLR, hints that this is generally not the case. The magnetic fields do not follow the spiral shape of the galaxy’s arms, nor are they in general perpendicular to the bones.

“Before SOFIA, it was difficult to image magnetic fields at high resolution over the entirety of the bones,” said Ian Stephens, an astrophysicist at Worcester State University. “We are now able to get so many independent measurements of the magnetic field direction across these bones, allowing us to really delve into the importance of the magnetic field in these massive filamentary clouds.”

Stephens is part of the Filaments Extremely Long and Dark: a MAgnetic Polarization Survey (FIELDMAPS) project, the first attempt to map the magnetic field of any galactic bone in its entirety. Of the ten bones the group plans to map, the first project completed by FIELDMAPS is that of G47, a giant filamentary bone within the Milky Way that is 200 light-years in length and 5 light-years in width.

“Magnetic fields…can potentially set the rate at which stars form in a cloud. They can also guide the flow of gas, shape the bones, and affect the quantity and size of the densest pockets of gas that will eventually collapse to form stars,” Stephens said. “By mapping the orientation of the fields, we can estimate the relative importance of the magnetic field to that of gravity to quantify how much magnetic fields affect the star formation process.”

The researchers did just that and were able to determine that the magnetic fields are strong enough to prevent gas in many areas from succumbing to gravitational collapse to form stars. They found the magnetic fields in the G47 bone were complex, changing directions frequently – though in the densest areas, they trended perpendicular to the bone. This means the parallel fields from the less dense regions are feeding material into the denser regions, where fields play a key role in the star formation rate by impeding the birth of new stars.

FIELDMAPS used the HAWC+ polarimeter aboard SOFIA, which determines the alignment of dust, allowing astrophysicists to sense the direction of the magnetic field so it can be observed from afar. This enabled the largest and most detailed maps ever made of magnetic fields across galactic bones.

The group has more galactic bones to analyze, which they plan to compare with computer simulations of spiral galaxies. Together, these results will help develop a more thorough description of the role of magnetic fields in spiral galaxies’ arms.

SOFIA is a joint project of NASA and the German Space Agency at DLR. DLR provides the telescope, scheduled aircraft maintenance, and other support for the mission. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California.

Science in the Southern Hemisphere: SOFIA Deploys to Chile

versión en español

By Maggie McAdam

NASA’s Stratospheric Observatory for Infrared Astronomy, or SOFIA, landed at the Santiago International Airport on March 18, 2022. Like other deployments to the Southern Hemisphere, SOFIA is temporarily changing its base of operations from Palmdale, California, to Santiago, Chile, to observe celestial objects that can only be seen from Southern Hemisphere latitudes. NASA and its partner of the SOFIA mission, the German Space Agency at DLR, are excited to deploy to Chile for the first time.

SOFIA on the runway at Santiago International Airport
SOFIA arrives at the Santiago International Airport. Credit: NASA/Raphael Ko

This is SOFIA’s first visit to South America, and its first short-term deployment that will last two weeks. The team will operate from the Santiago International Airport to accomplish eight science flights. SOFIA will primarily observe the Large and Small Magellanic Clouds during the deployment, which are two galaxies that are our Milky Way’s closest galactic neighbors. Both are gravitationally bound with the Milky Way and will eventually merge with our galaxy in several billion years.

“Scientific collaboration, particularly in astronomy, has been a cornerstone of the U.S.-Chile relationship dating back to the establishment of the Observatorio de Cerro Santa Lucia in Santiago more than 170 years ago,” said Richard Glenn, the U.S. Embassy Chile Chargé d’Affaires. “NASA’s SOFIA deployment to Chile is the next exciting milestone in that relationship, bringing us closer to the stars than ever before.”

This is called a short deployment because of the shorter time in country compared to SOFIA’s long deployments, where more than 25 flights are typically planned using multiple instruments. The SOFIA team is taking a single instrument, the Far Infrared Field Imaging Line Spectrometer, or FIFI-LS, and will observe several critical Southern Hemisphere celestial targets.

“We are thrilled to deploy to Chile so we can provide more access to the Southern Hemisphere skies for our scientific community,” said Naseem Rangwala, SOFIA’s project scientist. “We are increasing our deployment tempo with a focus on efficiency and prioritized targets, and we are grateful for the opportunity to do that from Santiago.”

Since the Large Magellanic Cloud, or LMC, is so close to our galaxy, SOFIA can observe it in great detail, on relatively small astronomical scales, to help scientists better understand how stars formed in the early universe. Having the context of the physical areas in which stars form is why these LMC observations are so powerful. Scientists cannot see detailed physical structures in distant, ancient galaxies, so, instead, galaxies like the LMC are observed as local stand-ins. The planned observations are to create the first map of ionized carbon in the LMC. These observations pair well with NASA’s upcoming Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory, or GUSTO mission, and they extend the legacy of the Herschel Space Observatory.

Large Magellanic Cloud
The Large Magellanic Cloud, one of the objects SOFIA will observe during deployment. Credit: ESA/NASA/Hubble

In addition to the observations of the Large Magellanic Cloud, SOFIA will observe supernova remnants to investigate how certain types of supernovas might have contributed to the abundance of dust in the early universe. SOFIA will also attempt its first observation to measure the primordial abundance of lithium by looking into the halo of our galaxy where clouds of neutral hydrogen can be found. These clouds have been relatively undisturbed and thus directly probe the properties of pristine gas that existed in the early universe. A successful observation of lithium could have implications for our understanding of fundamental physics and the early universe because there is a significant discrepancy in lithium abundance between the big-bang theory of the evolution of the universe and the observed abundance from astronomical measurements.

SOFIA is a joint project of NASA and the German Space Agency at DLR. DLR provides the telescope, scheduled aircraft maintenance, and other support for the mission. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California.

Media inquiries regarding SOFIA’s southern deployment should be sent to the NASA Ames newsroom.


Ciencia en el hemisferio sur: SOFIA se despliega en Chile

By Maggie McAdam

El Observatorio Estratosférico para Astronomía Infrarroja de la NASA, o SOFIA, aterrizó en el Aeropuerto Internacional de Santiago el 18 de marzo de 2022. Al igual que otros despliegues en el hemisferio sur, SOFIA cambia temporalmente su base de operaciones de Palmdale, California, a Santiago de Chile, para observar objetos celestes que solo pueden verse desde latitudes del hemisferio sur. La NASA y su socio en la misión SOFIA, la Agencia Espacial Alemana (DLR por sus siglas en alemán), están entusiasmados con el primer despliegue en Chile.

SOFIA on the runway at Santiago International Airport
SOFIA llega al Aeropuerto Internacional de Santiago. Crédito: NASA/Raphael Ko

Esta es la primera visita de SOFIA a Sudamérica, y su primer despliegue a corto plazo que durará dos semanas. El equipo operará desde el Aeropuerto Internacional de Santiago para realizar ocho vuelos científicos. Durante el despliegue, SOFIA observará principalmente la Nube Grande y la Nube Pequeña de Magallanes, dos galaxias que son las vecinas más cercanas de nuestra Vía Láctea. Las dos están ligadas gravitacionalmente a la Vía Láctea y acabarán fusionándose con nuestra galaxia dentro de varios miles de millones de años.

“La colaboración científica, especialmente en el campo de la astronomía, ha sido un pilar de la relación entre Estados Unidos y Chile que comenzó con el establecimiento del Observatorio de Cerro Santa Lucía en Santiago hace más de 170 años”, dijo Richard Glenn, Encargado de Negocios de la Embajada de Estados Unidos en Chile. “El despliegue de SOFIA de la NASA en Chile es el siguiente hito emocionante en esa relación, acercándonos a las estrellas como nunca antes”.

Este despliegue se considera corto debido al menor tiempo de permanencia en el país en comparación con los despliegues largos de SOFIA, en los que normalmente se planifican más de 25 vuelos con múltiples instrumentos. El equipo de SOFIA llevará un solo instrumento, el Espectrómetro de Línea de Imagen del Campo Infrarrojo Lejano, o FIFI-LS, y observará varios objetivos celestes críticos del hemisferio sur.

“Estamos encantados de desplegarnos en Chile para poder ofrecer a nuestra comunidad científica un mayor acceso a los cielos del hemisferio sur”, declaró Naseem Rangwala, científico del proyecto SOFIA. “Estamos aumentando nuestro ritmo de despliegue con un enfoque en la eficiencia y en los objetivos prioritarios, y estamos agradecidos por la oportunidad de hacerlo desde Santiago”.

Puesto que la Gran Nube de Magallanes, o LMC por sus siglas en inglés, está tan cerca de nuestra galaxia, SOFIA puede observarla con gran detalle, en escalas astronómicas relativamente pequeñas, para ayudar a los científicos a entender mejor cómo se formaron las estrellas en el universo primitivo. Tener el contexto de las zonas físicas en las que se forman las estrellas es la razón por la que estas observaciones de la LMC son tan potentes. Los científicos no pueden ver las estructuras físicas detalladas de las galaxias antiguas y lejanas, por lo que, en su lugar, las galaxias como la LMC se observan como sustitutos locales. Las observaciones previstas tienen por objeto crear el primer mapa del carbono ionizado en la LMC. Estas observaciones se combinan con el próximo Observatorio Espectroscópico de Terahercios ULDB Galáctico/Extra galáctico de la NASA, o misión GUSTO, y amplían el legado del Observatorio Espacial Herschel.

Large Magellanic Cloud
La Gran Nube de Magallanes, uno de los objetos que SOFIA observará durante su despliegue. Crédito: ESA/NASA/Hubble

Además de las observaciones de la Gran Nube de Magallanes, SOFIA observará restos de supernovas para investigar cómo ciertos tipos de supernovas podrían haber contribuido a la abundancia de polvo en el universo primitivo. SOFIA también intentará llevar a cabo su primera observación para medir la abundancia primordial de litio mirando en el halo de nuestra galaxia donde se encuentran las nubes de hidrógeno neutro. Estas nubes han permanecido relativamente inalteradas y, así, pueden investigar directamente las propiedades del gas prístino que existía en el universo primitivo. Una observación exitosa del litio podría tener implicaciones para nuestra comprensión de la física fundamental y del universo primitivo, ya que existe una discrepancia significativa en la abundancia de litio entre la teoría del Big Bang de la evolución del universo y la abundancia observada a partir de las mediciones astronómicas.

SOFIA es un proyecto conjunto de la NASA y la Agencia Espacial Alemana (DLR). DLR proporciona el telescopio, el mantenimiento programado para el avión y otros apoyos para la misión. El Centro de Investigación Ames de la NASA, en el Silicon Valley de California, administra el programa SOFIA, la ciencia y las operaciones de la misión en cooperación con la Asociación de Universidades de Investigación Espacial, con sede en Columbia, Maryland, y el Instituto SOFIA alemán de la Universidad de Stuttgart. El avión es mantenido y operado por el Armstrong Flight Research Center Building 703 de la NASA, en Palmdale, California.

Las preguntas de la prensa sobre el despliegue de SOFIA en el sur deben enviarse a la sala de prensa de la NASA en Ames.

SOFIA: Science Above the Clouds

This short video gives you a glimpse at our flying observatory – the Stratospheric Observatory for Infrared Astronomy, or SOFIA – and the science we do from the skies.

SOFIA is a joint project of NASA and the German Space Agency at DLR. DLR provides the telescope, scheduled aircraft maintenance, and other support for the mission. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California.

Tilted Galaxy Turns Studies Topsy-Turvy

by Anashe Bandari

Because the effects of observing a galaxy at an angle are complex, spiral galaxies are much easier to study if their orientation is just right – that is, if telescopes can see them face-on rather than at an angle. Now, observations of Caldwell 30, a spiral galaxy with a similar size and shape to our own, have begun to identify these effects.

NGC 7331 galaxy with circles showing the different sections of the galaxy.
Because NGC 7331 is viewed at an incline, there is a marked difference in the ionized carbon emission observed in different parts of the galaxy, depending on our observing perspective. Emission from within the delineated donut shape varies between the side of the galaxy that is closer to us (lower sector) and its far side (upper sector). This shows that viewing perspective has an effect on the origin of the ionized carbon emission observed. Credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona/Sutter et al., 2022

Jessica Sutter and Dario Fadda looked at the various factors that affect the detection of the ionized carbon emission – an important measurement in astronomy, as it can reveal star formation, cooling, and more – from Caldwell 30, including its angle of inclination. Because ionized carbon is so ubiquitous in astronomy, identifying its source ensures its proper usage.

“Knowing where the ionized carbon emission is coming from – whether photodissociation regions, or ionized hydrogen regions, or diffuse ionized gas – is going to affect how we might use it to trace molecular gas, star formation, or photodissociation conditions,” Sutter said. “Our observing angle may have an effect.”

From our point of view on Earth, Caldwell 30 is inclined at about 72 degrees. As a result of this inclination, Sutter and Fadda found the observed fraction of ionized carbon varies depending on which side of the galaxy is being looked at.

“That was both unexpected and semi-novel,” said Sutter, adding that it should be a significant consideration for researchers going forward, especially if they aren’t sure of the inclination of the galaxy they are studying. If the viewing angle is unknown, the contribution from various ionized carbon emission sources is hard to determine, impacting how the emission can be used in analyses.

As the only observatory capable of studying ionized carbon from within the Earth’s stratosphere for nearby galaxies, SOFIA is uniquely qualified to help clarify the role of a galaxy’s angle in its ionized carbon emission.

“One of the reasons more people haven’t looked at ionized carbon emission is because…you can’t do it from the ground. You need something at least from the stratosphere, if not in space,” Sutter said. “With SOFIA, we have some more opportunities to get these full maps.”

Looking ahead, the pair hopes to expand their analysis, which was recently published in The Astrophysical Journal, by mapping the ionized carbon emission from an additional set of galaxies using SOFIA.

SOFIA is a joint project of NASA and the German Space Agency at DLR. DLR provides the telescope, scheduled aircraft maintenance, and other support for the mission. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California.

How Magnetic Fields Help Feed a Supermassive Black Hole

by Anashe Bandari

A black hole at the center of a galaxy plays a role in the galaxy’s death, eating up their surrounding dust and gas and not leaving enough matter behind for new stars to form. Gravity alone, however, is not strong enough to account for all this material transfer on its own.

Image showing NGC 1097 with inset of the starburst ring in the center with magnetic streamlines
Gas streams outside and within the starburst ring (colorscale) of the spiral galaxy NGC 1097 follow the magnetic field, feeding the supermassive black hole with matter from the galaxy. Credit: NGC 1097: ESO/Prieto et al. (colorscale)

Theories have proposed that magnetic fields could be helping gravity in feeding black holes, spooning matter in their direction. With the help of observations from the Stratospheric Observatory for Infrared Astronomy, or SOFIA, these theories have now been confirmed. By mapping out the shape of the magnetic fields in the central region of NGC 1097, a spiral galaxy, researchers discovered the magnetic fields assist in directing dust and gas toward the supermassive black hole at the galaxy’s center.

“We can, for the first time, analyze the effect of the magnetic field in the gas flows toward [the central] star-forming regions using SOFIA and the galaxy’s center using radio polarimetric observations,” said Enrique Lopez-Rodriguez, lead author on the recent paper describing NGC 1097’s magnetic fields.

NGC 1097 has a region of intense star formation toward its center, known as a starburst ring. Because looking at magnetic fields in very dense areas is one of SOFIA’s strengths, Lopez-Rodriguez and his team used SOFIA to probe the dense regions merging into the starburst ring. This was complemented by radio polarimetric observations within the starburst ring, a different type of astronomical observation better suited for studying sparse regions.

The researchers found a striking difference in the morphology of the magnetic fields between the two regions. The SOFIA observations show the magnetic field feeding matter into the starburst ring, while the radio polarimetric observations show the magnetic field spiraling into the galaxy’s center, feeding the supermassive black hole.

Animation showing streamlines over NGC 1097
This figure shows the magnetic field orientation (streamlines) and direction (animated streamlines) in the central 1 kpc starburst ring of the spiral galaxy NGC 1097 using data from the radio polarimetric observations. Credit: Lopez-Rodriguez et al.

But despite this striking difference, the two are not fully disconnected: The study proves that the magnetic fields in the galaxy help deliver gas and dust to the black hole at its center. Altogether, the large-scale fields follow the shape of NGC 1097’s spiral arms, channeling matter from the arms to the starburst ring in its innermost regions, and from the starburst ring deeper toward the black hole, where it can eat the material up.

This confirms that it is not just gravity that helps a black hole feed on the material in its host galaxy, but magnetic fields also play a role.

“Our observations also provide evidence that the magnetic fields located in the proximity of the black holes at the center of active galaxies may be coming from the large-scale magnetic field in the host galaxy,” Lopez-Rodriguez said.

This first observation of magnetic fields nourishing black holes helps answer critical questions about how galaxies evolve, and ultimately die.

Orientations of the magnetic field within the starburst ring of NGC 1097
Orientations of the magnetic field within the starburst ring of NGC 1097. The blue lines indicate far-infrared data obtained from SOFIA, while the red and orange lines are radio polarimetric observations. The magnetic field has different configurations at far infrared wavelengths compared to radio wavelengths. Credit: Lopez-Rodriguez et al.

SOFIA is a joint project of NASA and the German Space Agency at DLR. DLR provides the telescope, scheduled aircraft maintenance, and other support for the mission. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California.