Posted on by Jason Major

Researchers Present the Sharpest Image of Pluto Ever Taken from Earth

A “speckle image” reconstruction of Pluto and its largest moon, Charon (Gemini Observatory/NSF/NASA/AURA)

Real planet, dwarf planet, KBO, who cares? What matters here is that astronomers have created the sharpest image of Pluto ever made with ground-based observations — and developed a new way to verify potential Earth-like exoplanets at the same time.

Here’s how they did it:


After taking a series of quick “snapshots” of Pluto and Charon using a recently-developed camera called the Differential Speckle Survey Instrument (DSSI), which was mounted on the Gemini Observatory’s 8-meter telescope in Hawaii, researchers combined them into a single image while canceling out the noise caused by turbulence and optical aberrations. This “speckle imaging” technique resulted in an incredibly clear, crisp image of the distant pair of worlds — especially considering that 1. it was made with images taken from the ground, 2. Pluto is small, and 3. Pluto is very, very far away.

Read: Why Pluto is No Longer a Planet

Less than 3/4 the diameter of our Moon, Pluto (and Charon, which is about half that size) are currently circling each other about 3 billion miles from Earth — 32.245 AU to be exact. That’s a long way off, and there’s still much more that we don’t know than we do about the dwarf planet’s system. New Horizons will fill in a lot of the blanks when it passes close by Pluto in July 2015, and images like this can be a big help to mission scientists who want to make sure the spacecraft is on a safe path.

“The Pluto-Charon result is of timely interest to those of us wanting to understand the orbital dynamics of this pair for the 2015 encounter by NASA’s New Horizons spacecraft,” said Steve Howell of the NASA Ames Research Center, who led the Gemini imaging study.

See images of Pluto taken by Hubble here.

In addition, the high resolution achievable through the team’s speckle imaging technique may also be used to confirm the presence of exoplanet candidates discovered by Kepler. With an estimated 3- to 4-magnitude increase in imaging sensitivity, astronomers may be able to use it to pick out the optical light reflected by a distant Earth-like world around another star.

Speckle imaging has been used previously to identify binary star systems, and with the comparative ability to “separate a pair of automobile headlights in Providence, RI, from San Francisco, CA” there’s a good chance that it can help separate an exoplanet from the glare of its star as well.

The research was funded in part by the National Science Foundation and NASA’s Kepler discovery mission, and will be published in the journal Publications of the Astronomical Society of the Pacific in October 2012. Read more here.

Main image: the first speckle reconstructed image for Pluto and Charon from which astronomers obtained not only the separation and position angle for Charon, but also the diameters of the two bodies. North is up, east is to the left, and the image section shown is 1.39 arcseconds across. Resolution of the image is about 20 milliarcseconds rms. Credit: Gemini Observatory/NSF/NASA/AURA. Inset: the Gemini North telescope on the summit of Mauna Kea. (Gemini Observatory)

Posted on by Jason Major

First Images in a New Hunt for Dark Energy

Zoomed-in image from the Dark Energy Camera of the barred spiral galaxy NGC 1365, about 60 million light-years from Earth. (Dark Energy Survey Collaboration)

The ongoing search for dark energy now has a new set of eyes: the Dark Energy Camera, mounted on the 4-meter Victor M. Blanco telescope at the National Science Foundation’s Cerro Tololo Inter-American Observatory in Chile. The culmination of eight years of planning and engineering, the phone-booth-sized 570-megapixel Dark Energy Camera has now gathered its very first images, capturing light from cosmic structures tens of millions of light-years away.

Eventually the program’s survey will help astronomers uncover the secrets of dark energy — the enigmatic force suspected to be behind the ongoing and curiously accelerating expansion of the Universe.

Zoomed-in image from the Dark Energy Camera of the Fornax cluster

“The Dark Energy Survey will help us understand why the expansion of the universe is accelerating, rather than slowing due to gravity,” said Brenna Flaugher, project manager and scientist at Fermilab.

Read more: Polar Telescope Casts New Light on Dark Energy

The most powerful instrument of its kind, the Dark Energy Camera will be used to create highly-detailed color images of  a full 1/8th of the night sky — about 5,000 square degrees — surveying thousands of supernovae, galactic clusters and literally hundreds of millions of galaxies, peering as far away as 8 billion light-years.

The survey will attempt to measure the effects of dark energy on large-scale cosmic structures, as well as identify its gravitational lensing effects on light from distant galaxies. The images seen here, acquired on September 12, 2012, are just the beginning… the Dark Energy Survey is expected to begin actual scientific investigations this December.

Full Dark Energy Camera composite image of the Small Magellanic Cloud

“The achievement of first light through the Dark Energy Camera begins a significant new era in our exploration of the cosmic frontier,” said James Siegrist, associate director of science for high energy physics with the U.S. Department of Energy. “The results of this survey will bring us closer to understanding the mystery of dark energy, and what it means for the universe.”

Read more on the Symmetry Magazine article here, and you can also follow the Dark Energy Survey on Facebook here. (The Fermilab press release can be found here.)

Images: Dark Energy Survey Collaboration. Inset image: the 4-meter Blanco Telescope dome at CTIO (NOAO)

The Dark Energy Survey is supported by funding from the U.S. Department of Energy; the National Science Foundation; funding agencies in the United Kingdom, Spain, Brazil, Germany and Switzerland; and the participating DES institutions.

 

Posted on by Nancy Atkinson

With Proposed Cuts, Can the US Continue to be a Leader in Astronomy? Q & A with NOAO Director David Silva

The Kitt Peak Observatory

Last week, a report issued by the National Science Foundation’s Division of Astronomical Sciences suggested de-funding several ground-based observatories along with other money-saving strategies to help offset budget shortfalls in US astronomy which have been projected to be as much as 50%. The report recommended the closure of iconic facilities such as the Very Long Baseline Array (VLBA) and the Green Bank Radio Telescope, as well as shutting down four different telescopes at the Kitt Peak Observatory by 2017.

Universe Today talked with the Director of the National Optical Astronomy Observatory (NOAO), Dr. David Silva for his reactions to the report.

Universe Today: What is your initial reaction to the STP portfolio review:

David Silva: “It’s disappointing, but not completely unexpected. I think the biggest challenge for the overall US community is they’re going to lose access to a lot of world-class, cutting-edge facilities. This is roughly somewhere between eight hundred to a thousand nights of open access time which is going to be defunded over the next three years or so. That’s a huge culture change for US astronomy.

UT: Do you see this affecting the researchers at smaller facilities and universities the most?

Silva: Definitely. Clearly, the situation is now that if you’re at an institution that has its own facility, everything should be OK. But if you’re at an institution that does not have access to its own facility, you’re in a bad situation. So that naturally segregates the bigger universities versus the smaller universities.

I should say there is a caveat, in that we are in an era now in professional astronomy where surveys are now becoming a much stronger component of what we do. Surveys are the big wide-field surveys both from space and from the ground which are producing massive datasets that are open to everyone. So, what’s really happening is this culture change from people having to compete for one or two nights a year on a telescope to potentially working on the big datasets. So, how that transition occurs remains to be seen. But the loss of all these open access nights will definitely be a shock to the system.

UT: Do you see the new report as being overly pessimistic or do you think it’s spot on of what’s actually going to be taking place in astronomy next few years, such as in one scenario which described that only 50% of projected funding will be available?

Silva: I have no opinion on that. That was a boundary condition that the report used, and if I could predict that I would be in a different industry!

UT: Do you see any potential silver lining here, that this kind of tight funding could streamline things, or could help in the “persistent mismatch between the production rate of Ph.D.s and the number of tenure-track faculty or long-term astronomy positions” that the report talked about?

Silva: No. I think the higher-level issue is that astronomy in the last 20 years has been a field where the number of people who are professional astronomers has grown in this country because of a fortuitous funding cycle from all three of the major funding agents, NASA, NSF and the Department of Energy. But we are now in a downward cycle in funding for astronomy at the federal level and there is going to be a squeeze now. I think that one of the choices we’re going face as there is this squeeze and people begin to leave the field, how do we make sure that the those who are still in the field — especially our younger colleagues – that they are given the mentoring and nurturing and support they need to have vital careers.

But there’s a growing mismatch between the numbers of people who want funding and the funding that is available, there’s no two ways about it.

UT: Any final thoughts or things that you think are people I’m important for people to know about?

Silva: One of the opportunities that it creates on Kitt Peak is the ability to continue to move forward on our BigBOSS collaboration, which is a proposal to put a 5,000 target, multi-object spectrograph on the 4-meter Mayall telescope at Kitt Peak National Observatory, which allows you to do a large dark energy characterization experiment. The instrument is also exceptionally powerful for doing a variety of other investigations like galactic archaeology to map out kinematics in the galaxy, the chemical composition and the motions of galaxies and stars, and other very large data projects like that.

This report was actually quite supportive of that project moving forward. So even though reports recommend the NSF divest funding in the Mayall Telescope as an open-access telescope, it suggests there are ways forward to convert it from an open access platform to a survey facility. And that’s, I think, a silver lining in this. It doesn’t solve that cultural issue, but it was does mean we can continue to do high impact science with that instrument.

But I do see this as a big cultural change. A key question perhaps is, does the US have strong national observatory or not? And this report is leaning in the direction of not.

You can read an initial statement from NRAO (National Radio Astronomy Observatory) and AURA (Association of Universities for Research in Astronomy) on the AST report here, and another following statement from AURA here.

Posted on by Jason Major

Polar Telescope Casts New Light On Dark Energy And Neutrino Mass

The 10-meter South Pole Telescope in Antarctica at the Amundsen-Scott Station. (Daniel Luong-Van, National Science Foundation)

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Located at the southermost point on Earth, the 280-ton, 10-meter-wide South Pole Telescope has helped astronomers unravel the nature of dark energy and zero in on the actual mass of neutrinos — elusive subatomic particles that pervade the Universe and, until very recently, were thought to be entirely without measureable mass.

The NSF-funded South Pole Telescope (SPT) is specifically designed to study the secrets of dark energy, the force that purportedly drives the incessant (and apparently still accelerating) expansion of the Universe. Its millimeter-wave observation abilities allow scientists to study the Cosmic Microwave Background (CMB) which pervades the night sky with the 14-billion-year-old echo of the Big Bang.

Overlaid upon the imprint of the CMB are the silhouettes of distant galaxy clusters — some of the most massive structures to form within the Universe. By locating these clusters and mapping their movements with the SPT, researchers can see how dark energy — and neutrinos — interact with them.

“Neutrinos are amongst the most abundant particles in the universe,” said Bradford Benson, an experimental cosmologist at the University of Chicago’s Kavli Institute for Cosmological Physics. “About one trillion neutrinos pass through us each second, though you would hardly notice them because they rarely interact with ‘normal’ matter.”

If neutrinos were particularly massive, they would have an effect on the large-scale galaxy clusters observed with the SPT. If they had no mass, there would be no effect.

The SPT collaboration team’s results, however, fall somewhere in between.

Even though only 100 of the 500 clusters identified so far have been surveyed, the team has been able to place a reasonably reliable preliminary upper limit on the mass of neutrinos — again, particles that had once been assumed to have no mass.

Previous tests have also assigned a lower limit to the mass of neutrinos, thus narrowing the anticipated mass of the subatomic particles to between 0.05 – 0.28 eV (electron volts). Once the SPT survey is completed, the team expects to have an even more confident result of the particles’ masses.

“With the full SPT data set we will be able to place extremely tight constraints on dark energy and possibly determine the mass of the neutrinos,” said Benson.

“We should be very close to the level of accuracy needed to detect the neutrino masses,” he noted later in an email to Universe Today.

The South Pole Telescope's unique position allows it to watch the night sky for months on end. (NSF)

Such precise measurements would not have been possible without the South Pole Telescope, which has the ability due to its unique location to observe a dark sky for very long periods of time. Antarctica also offers SPT a stable atmosphere, as well as very low levels of water vapor that might otherwise absorb faint millimeter-wavelength signals.

“The South Pole Telescope has proven to be a crown jewel of astrophysical research carried out by NSF in the Antarctic,” said Vladimir Papitashvili, Antarctic Astrophysics and Geospace Sciences program director at NSF’s Office of Polar Programs. “It has produced about two dozen peer-reviewed science publications since the telescope received its ‘first light’ on Feb. 17, 2007. SPT is a very focused, well-managed and amazing project.”

The team’s findings were presented by Bradford Benson at the American Physical Society meeting in Atlanta on April 1.

Read more on the NSF press release here.