cerro tololo inter american observatory

Cerro Tololo Trails : Early one moonlit evening car lights left a wandering trail along the road to the Chilean Cerro Tololo Inter-American Observatory. Setting stars left the wandering trails in the sky. The serene view toward the mountainous horizon was captured in a telephoto timelapse image and video taken from nearby Cerro Pachon, home to Gemini South. Afforded by the mountaintop vantage point, the clear, long sight-line passes through layers of atmosphere. The changing atmospheric refraction shifts and distorts the otherwise steady apparent paths of the stars as they set. That effect also causes the distorted appearance of Sun and Moon as they rise or set near a distant horizon. via NASA

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This composite image is a view of the colorful Helix Nebula taken with the Advanced Camera for Surveys aboard NASA’s Hubble Space Telescope and the Mosaic II Camera on the 4-meter telescope at Cerro Tololo Inter-American Observatory in Chile. The object is so large that both telescopes were needed to capture a complete view. The Helix is a planetary nebula, the glowing gaseous envelope expelled by a dying, sun-like star. The Helix resembles a simple doughnut as seen from Earth. But looks can be deceiving. New evidence suggests that the Helix consists of two gaseous disks nearly perpendicular to each other.

One possible scenario for the Helix’s complex structure is that the dying star has a companion star. One disk may be perpendicular to the dying star’s spin axis, while the other may lie in the orbital plane of the two stars. The Helix, located 690 light-years away, is one of the closest planetary nebulas to Earth.

The Hubble images were taken on November 19, 2002; the Cerro Tololo images on Sept. 17-18, 2003.

Object Name: Helix Nebula

Image Type: Astronomical

Credit: NASA, ESA, C.R. O'Dell (Vanderbilt University), M. Meixner and P. McCullough (STScI)

Time And Space

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PUNCHING ABOVE ITS WEIGHT, A BROWN DWARF LAUNCHES A PARSEC-SCALE JET

Astronomers using the SOAR telescope at the Cerro Tololo Inter-American Observatory report the discovery of a spectacular extended jet from a young brown dwarf. With masses too low to sustain hydrogen fusion in their interiors, brown dwarfs occupy the mass range between stars and giant planets. While young stars are commonly found to launch jets that extend over a light-year or more, this is the first jet with a similar extent detected from a brown dwarf. The result lends new insight into how substellar objects form.

Intrinsically faint, brown dwarfs have been more elusive and difficult to study than stars. Although they are often portrayed as exotic creatures as a result, brown dwarfs are actually far more numerous in our galaxy than stars like the Sun.

The discovery, accepted for publication in the Astrophysical Journal, supports the emerging picture that brown dwarfs form similarly to stars.

The image shows the jet, HH 1165, launched by the brown dwarf Mayrit 1701117 in the outer periphery of the 3 million year old Sigma Orionis cluster. Traced by emission from singly ionized sulfur, which appears green in the image, the jet extends 0.7 light-year (equivalent to 0.2 parsec) northwest of the brown dwarf. The emission knots along the jet reveal that the mass loss is time variable, probably a result of episodic accretion onto the brown dwarf. The red nebulosity southeast of the brown dwarf is a reflection nebula that traces the outflow cavity in the direction of the counterjet.

While outflows have been detected previously from young brown dwarfs, the earlier detections were of “microjets” 10 times smaller in extent. “Our result shows that brown dwarfs can launch parsec-scale jets similar to those from young stars,” explains Basmah Riaz, who led the study.

The image, taken with the SOAR telescope using the SOAR Adaptive Optics Module, was obtained in several hours of integration time. As described by co-author Cesar Briceno: “We could see the surprisingly extended jet emission after the first 30 minutes of integration. It was a real ‘Wow’ moment!”

For some time, astronomers have suspected that brown dwarfs form much like stars. Like stars, brown dwarfs are known to be surrounded by disks at birth and to build up their masses by accretion from molecular cloud cores. The current discovery goes a step further and shows that, like stars, brown dwarfs launch powerful jets and that they build up their mass through an unsteady, episodic process.

“The HH 1165 jet shows all the familiar hallmarks of outflows from stars: emission knots, a cavity with reflection nebulosity, and bow shocks at the ends of the flow. It checks all the boxes quite convincingly,” commented co-author Emma Whelan.

While it may seem counterintuitive that mass loss (in a jet) is an integral part of how an object grows or gains mass, this situation may arise because of excess angular momentum. When spinning skaters pull in their arms, they spin faster as a result of conservation of angular momentum. Similarly, when large, slowly rotating molecular cloud cores collapse, they may spin up too fast to squeeze down to the much smaller sizes of stars.

Riaz speculates that indeed, “Molecular cloud cores have much more angular momentum than can be contained by stars or brown dwarfs. So the system needs to lose angular momentum for the object to grow in mass. By removing angular momentum from the system, jets help solve the `angular momentum problem’ faced by stars as well as brown dwarfs.”

To test this hypothesis, the team is on the hunt for more extended jets from brown dwarfs, to understand how commonly they occur.


TOP IMAGE….The HH 1165 jet launched by a brown dwarf in the outer periphery of the Sigma Orionis cluster. Traced by emission from singly ionized sulfur, which appears green in the image, the jet extends 0.7 light-year (equivalent to 0.2 parsec) northwest of the brown dwarf.

LOWER IMAGE….Cerro Tololo Inter-American Observatory is managed by the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy Inc. (AURA) under a cooperative agreement with the National Science Foundation.

NGC 3576: The Statue of Liberty Nebula : Whats happening in the Statue of Liberty nebula? Bright stars and interesting molecules are forming and being liberated. The complex nebula resides in the star forming region called RCW 57. This image showcases dense knots of dark interstellar dust, bright stars that have formed in the past few million years, fields of glowing hydrogen gas ionized by these stars, and great loops of gas expelled by dying stars. A detailed study of NGC 3576, also known as NGC 3582 and NGC 3584, uncovered at least 33 massive stars in the end stages of formation, and the clear presence of the complex carbon molecules known as polycyclic aromatic hydrocarbons . PAHs are thought to be created in the cooling gas of star forming regions, and their development in the Suns formation nebula five billion years ago may have been an important step in the development of life on Earth. The featured image was taken at the Cerro Tololo Inter-American Observatory in Chile. via NASA

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This image of 30 Doradus, the Tarantula Nebula, in the Large Magellanic Cloud (LMC) was taken with the Curtis Schmidt telescope at Cerro Tololo Inter-American Observatory (CTIO) in Chile, as part of the Magellanic Cloud Emission Line Survey (MCELS) project. The Tarantula Nebula is a giant star-forming region, where energy from hot, young stars in the region creates dramatic voids and filaments in the surrounding gas. Located 160,000 light-years distant in the southern constellation Dorado, the LMC is considered the closest large galaxy to Earth.  Because of the proximity and low foreground absorption of the LMC, it is an ideal laboratory both for studies of individual HII regions, supernova remnants, and superbubbles, and for investigations of global properties using samples of these objects. MCELS is designed to provide uniform datasets in optical emission lines that are necessary to conduct this research. The MCELS observations toward the 30 Doradus region have been used to investigate the physical properties of the HII region, examine the physical conditions of supernova remnants in the field, and study the large-scale structure of the ionized gas.  This color image was produced using three separate exposures taken in hydrogen (red), sulfur (green), and oxygen (blue) filters. Caption: NOAO. Please read Conditions of Use before downloading. S. POINTS, C. SMITH, R. LEITON, C. AGUILERA AND NOAO/AURA/NSF

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SYMMETRY MAGAZINE
Art of Darkness
By Rashmi Shivni

The Dark Energy Survey’s art show offers a glimpse of the expanding universe.
Imagine a clear night in the mountains, away from glaring city lights. In the sky, gleaming speckles from distant stars cascade into the bright streams of the Milky Way. Almost everything in sight is part of our home galaxy.
To provide a glimpse beyond our galaxy and into an ever-expanding universe, the Department of Energy’s Fermilab is hosting the Art of Darkness, an exhibition by Dark Energy Survey collaborators. The exhibit opened Feb. 19 in the Fermilab Art Gallery and showcases images from celestial objects from DES’ Dark Energy Camera, DECam.
“We see so much information in the artwork that ends up being a small part of the whole DES footprint,” says Brian Nord, an astrophysicist and contributor to the DES art exhibit. “This showcase highlights the depth of a universe we don’t completely see with the naked eye.”
DES is a five-year survey that covers one-eighth of the sky to better describe dark energy–the force driving the universe’s accelerated expansion. The collaboration has more than 400 scientists from around 30 institutions. It uses the 570-megapixel DECam, one of the largest digital cameras in the world, perched atop the Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile.
The select few galaxies in the exhibit are from a narrow swath of the sky survey. Creating these photographs for the gallery requires an image-processing pipeline, a method of “cleaning up” the images by removing artifacts such as satellites, airplane or cosmic ray trails, or defects from the camera hardware, says Nikolay Kuropatkin, a DES computational physics software developer.
“We use this pipeline for our scientific surveys, but it turns out to be a good tool for artwork as well,” says Kuropatkin.

DECam is a monochromatic camera. Part of the exhibit process required Marty Murphy, an operations specialist in Fermilab’s Accelerator Division, and Nord to add color and further edit the images with an artistic eye.
Five different filters are individually placed between the telescope and camera to gather color information about the galaxy in view. Each filter corresponds to a different bandwidth, or a range of frequencies, on the electromagnetic spectrum. Those single-filter images are then combined to produce a full-color photo.
“A lot of the information in the initial pictures is lost because lots of light emits from the invisible ends of the electromagnetic spectrum,” Murphy says. “We try to bring out colors from the visible spectrum that somewhat represent what’s there and fix any discrepancies between reality and the artwork.”
This close-to-reality representation also helps scientists understand the properties of the galaxies in view. For instance, small clusters that appear red or warmer in color tell us that they are further away from us due to the expansion of the universe, says Brian Yanny, a DES data management project scientist.
“From that we can figure out how big space is and how dark energy might be affecting the size of the universe from the redshift of the object,” he says.
But the art gallery is made of more than just galaxy images. There’s a 3D print of the cosmic web derived from a computer simulation. There’s also a colorful dark matter map of the actual cosmic web that DES observes made using gravitational lensing, a distortion seen when light from background galaxies bends from a massive foreground object.
“Once you know the explanations behind the workings of the cosmos, you realize there are forces out there that make the universe beautiful,” Yanny says. “We’ve come to understand that dark matter holds the shape of spiral galaxies, which have a rapid and unstable spin. Without dark matter, we would not experience the cosmos the way we do now.”
Alongside the DECam photos are images and time-lapse videos from the Blanco Telescope and the surrounding landscapes that provide another perspective of how the very act of research helps bring out the beauty of the universe. The images (on display at Fermilab through April) come from 11 DES collaborators and were collected over the first three seasons of observations, which ended in February. DES will take data for two more years, from August to February.
“I hope the images from the camera combined with the pictures from the site can somehow merge two perspectives,” Nord says. “In essence, it’s humans looking out to the cosmos and the universe looking back at us.”

What’s the closest active galaxy to planet Earth? That would be Centaurus A, only 11 million light-years distant. Spanning over 60,000 light-years, the peculiar elliptical galaxy is also known as NGC 5128. Forged in a collision of two otherwise normal galaxies, Centaurus A’s fantastic jumble of young blue star clusters, pinkish star forming regions, and imposing dark dust lanes are seen here in remarkable detail. The colorful galaxy portrait was recorded under clear Chilean skies at the Cerro Tololo Inter-American Observatory. Near the galaxy’s center, left over cosmic debris is steadily being consumed by a central black hole with a billion times the mass of the Sun. As in other active galaxies, that process likely generates the radio, X-ray, and gamma-ray energy radiated by Centaurus A.

Image Credit & Copyright: SSRO-South (Steve Mazlin, Jack Harvey, Daniel Verschatse, Rick Gilbert) and Kevin Ivarsen (PROMPT / CTIO / UNC)

Globule Goes Chomp

The flower-like image of this star-forming region in Earth’s southern skies was imaged using a 64-megapixel Mosaic imaging camera on the National Science Foundation’s Victor M. Blanco telescope at Cerro Tololo Inter-American Observatory.

Cometary globules are isolated, relatively small clouds of gas and dust within the Milky Way. This example, called CG4, is about 1,300 light years from Earth. Its head is some 1.5 light-years in diameter, and its tail is about eight light-years long. The dusty cloud contains enough material to make several Sun-sized stars. CG4 is located in the constellation of Puppis.

The head of the nebula is opaque, but glows because it is illuminated by light from nearby hot stars. Their energy is gradually destroying the dusty head of the globule, sweeping away the tiny particles which scatter the starlight. This particular globule shows a faint red glow from electrically charged hydrogen, and it seems about to devour an edge-on spiral galaxy (ESO 257-19) in the upper left. In reality, this galaxy is more than a hundred million light-years further away, far beyond CG4. The image from the Blanco 4-meter telescope was taken in four filters, three of which are for blue, green and near-infrared light. The fourth is designed to isolate a specific color of red, known as hydrogen-alpha, which is produced by warm hydrogen gas.

Image Credit: T.A. Rector/University of Alaska Anchorage, T. Abbott and NOAO/AURA/NSF

A new Einstein Ring: Distant galaxy lensed by gravity

A multinational team of astronomers has found an Einstein Ring, a rare image of a distant galaxy lensed by gravity. The scientists, from Spain, Italy and the USA, report their discovery in Monthly Notices of the Royal Astronomical Society.

In his seminal general theory of relativity published a century ago, Albert Einstein predicted that gravity would distort the fabric of spacetime, and that light would follow curved paths as a result. Astronomers first observed this effect in 1919, by measuring the position of stars near the Sun during the 1919 total solar eclipse, and noting a slight shift resulting from the gravitational field of our nearest star. On a larger scale, light from distant galaxies is bent by black holes and massive galaxies that lie between them and Earth. The intervening objects act as lenses, creating arcs and ‘Einstein rings’ of light.

These rings are still comparatively rare and usually appear as small features in the sky. This makes them hard to see clearly, and most are observed with radio telescopes, or with the Hubble Space Telescope. Their rarity derives from the huge distances involved, and the low probability of our Galaxy, the lens galaxy and the distant galaxy all being almost exactly in line.

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