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New Sky Survey To Catch Exploding Stars In The Act

ptf-image

Astronomers using NERSC’s Real-Time Detection pipeline uncovered supernova SN2009av-1a in the act of exploding. At left, the image of a galaxy 800 million light-years away was created by layering observations taken by the Palomar Transient Factory camera from February 23-27. Second from left is the image captured by the PTF camera on February 28. Scientists used NERSC to digitally subtract the earlier image from the new one to expose the supernova. (Palomar Transient Factory/Dovi Poznanski, Berkeley Lab)

An innovative new sky survey called the Palomar Transient Factory (PTF) will use a 48-inch telescope together with the U.S. Department of Energy’s (DOE’s) National Energy Research Scientific Computing Center (NERSC) to discover relatively rare and fleeting cosmic events like supernovae and gamma ray bursts.  The survery is already in progress, and during the commissioning phase alone, the survey has already uncovered more than 40 supernovae.  Astronomers expect to discover thousands more each year.

“This survey is a trail blazer in many ways – it is the first project dedicated solely to finding transient events, and as part of this mission we’ve worked with NERSC to develop an automated system that will sift through terabytes of astronomical data every night to find interesting events, and have secured time on some of the world’s most powerful ground-based telescopes to conduct immediate follow up observations as events are identified,” says Shrinivas Kulkarni, a professor of astronomy and planetary science at the California Institute of Technology (Caltech), and Director of Caltech Optical Observatories. He is also principle investigator of the PTF survey.

“This truly novel survey combines the power of a wide-field telescope, a high-resolution camera, and high-performance network and computing, as well as the ability to conduct rapid follow-up observations with telescopes around the globe for the first time,” says Peter Nugent, a computational staff scientist in Berkeley Lab’s Computational Research Division (CRD) and the NERSC Analytics Group. Nugent is also the Real-time Transient Detection Lead for the PTF project.

Every night the PTF camera – a 100-megapixel machine mounted on the 48-inch Samuel Oschin Telescope at Palomar Observatory in Southern California – will automatically snap pictures of the sky, then send those images to NERSC for archiving via a high-speed network provided by DOE’s Energy Sciences Network (ESnet) and the National Science Foundation’s (NSF’s) High Performance Wireless Research and Education Network (HPWREN).

At NERSC, computers running machine-learning algorithms in the Real-time Transient Detection pipeline scour the PTF observations for “transient” sources, cosmic objects that change in brightness or position, by comparing the new observations with all of the data collected from previous nights. Within minutes after interesting event is discovered, machines at NERSC will send its coordinates to Palomar’s 60-inch telescope for follow up observations.

“We are currently uncovering one event every 12 minutes. This project will be keeping the astronomical community busy for quite a while,” says Kulkarni.

The primary target of the sky survey are Type Ia and Type II supernovae.

Because they are relatively uniform in brightness, Type Ia supernovae act as cosmic lighthouses, helping astronomers judge the distance scale of the universe. Many astronomers participating in the PTF survey are specifically searching for these phenomena.

And Type II supernovae, the kind cause by the detonation of a massive star that’s run out of fuel, blast heavy elements into interstellar space, where they eventually form new stars and planets.

“These tools are extremely valuable because they not only help us identify supernova, they uncover them while the star is in the act of exploding,” says Robert Quimby of Caltech, who is the software lead for the PTF program. “This gives us valuable information about how cosmic dust is spread across the universe.”

“It is very exciting to find so many supernovae, so early in the project. It’s like we’ve just turned on the spigot and are now waiting for the fire hose to blast,” says Quimby.

Source: Lawrence Berkeley National Labs

Comments on this entry are closed.

  • star-grazer west coast June 15, 2009, 5:23 PM

    It is interesting they are using DOE MERSC for this interesting survery. Finding a SN every 12 minutes, no doubt there will be some ‘exotic’ type SN not now known discovered. This will really increase our knowledge of what happens with exploding stars, and if lucky, stars ready to explode and see the results!!!!

  • Jon Hanford June 15, 2009, 5:34 PM

    This is awesome that large amounts of imaging data from the 48″ Schmidt ( about 100Gb/night) will will be able to be searched and analyized using supercomputers at LBNL in near real time. Objects of interest can be imaged multiple times to construct light curves, or if daylight or moonlight interferes, pass off the positional data to other observatories able to continue obtaining observations. Interesting use of supercomputers, high-speed internet connections and large, state of the art CCD detectors to scour the heavens.

  • ND June 15, 2009, 7:17 PM

    bad news for amateur SN hunters. was bound to happen.

  • Jon Hanford June 16, 2009, 11:02 AM

    Actually, amateur SN hunters have had to deal with this automated, robotic search method for several years, only with smaller telescopes or telephoto lenses (i.e. KAIT, Tim Puckett’s SN program, etc., giving traditional visual SN hunters like Rev. Robert Evans a run for the money). But it seems that amateurs are getting into robotic hunting of SNe (the recent SN 2008ha was discovered through Puckett’s program by a 14 year old girl!) and the July 2009 issue of Sky & Telescope describes an Australian amateur’s robotic SN search efforts done on the cheap from his own back porch. He’s already had solo discoveries of 2 SNe using an off-the-shelf 9.25in Celestron and a home-built CCD camera. I see a trend developing here among advanced amateurs. And that’s great :)

  • ND June 16, 2009, 11:14 AM

    ooh. home made CCD camera. need to check that issue of S&T.

  • Jon Hanford June 16, 2009, 7:41 PM

    I found all sorts of great info and links on the current configuration and PTF program at the Samuel Oschin Telescope here: http://www.astro.caltech.edu/palomar/sot.html . It’s also interesting to remember this is the 48 inch Schmidt Camera that produced the Northern Hemisphere version of the popular Palomar Observatory Sky Survey I (POSS I) and the Digital POSS II (DPOSS II) that amateurs and pros use every day. History of these surveys and links to them are also available at the above link. Great to see a groundbreaking telescope still producing state-of-the-art science :)

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