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From Radio-Controlled Planes to the Cosmos – Hu Zhan
Cosmologist and co-chair of two LSST science collaborations, Hu Zhan visits the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) at the Xinglong Observing Station. The observing station is about 90 miles northeast of the NAOC headquarters in Beijing. A 4-meter reflecting Schmidt telescope with a field of view of 5 degrees, LAMOST has 4,000 fibers for spectroscopic observations.
As tenuous as a connection between television repair, radio-controlled airplanes, and the LSST may seem, Hu Zhan, cosmologist and co-chair of two LSST science collaborations, cites those two hands-on hobbies as crucial influences on his career.
“My father assembled our family’s first TV set from parts,” Hu said. “My picking up that hobby and playing with those magic parts and tools was very effective for inspiring interest in science and technology.”
As an aerospace engineering student at Beijing University of Aeronautics and Astronautics, Hu particularly enjoyed building and flying radio-controlled model planes with a team of enthusiastic fellow students. “Then R/C planes were built by hand and really required craftsmanship. Now, almost every toy store sells ready-to-fly R/C planes. Hu “admits with some embarrassment” that he owns a couple of such R/C helicopters in his collection. “I’m actually impressed by the fact that they are able to miniaturize and integrate the receiver, servos, and gyro into such a tiny space. This is in some way analogous to LSST. Transformative technology really makes the difference.”
Enthusiasm for “being part of the enterprise that is transforming the field of astronomy” led Hu to join the LSST project in 2004 when he was a postdoctoral fellow at the University of California at Davis. Following a stint as an assistant project physicist at UC Davis, he accepted a professorship at the National Astronomical Observatory of China (NAOC), where he researches, among other things, the capability of LSST to determine the properties of dark energy. He co-chairs the Large-Scale Structure/Baryon Acoustic Oscillations Science Collaboration with Eric Gawiser and the Cosmology Interest Group with Rachel Bean. He is also leading the effort to form a Chinese consortium to join LSST.
Hu is excited about both LSST’s scientific potential and its unprecedented contribution to data-intensive astronomy. “LSST will open the era of data intensive astronomy and change the way astronomical research is done,” he said. “Managing and processing 200 petabytes of data is a major computational challenge! It’s actually not so easy to grasp how difficult the task is because the concept is so abstract for many of us.”
As an example of LSST’s transformative potential, Hu described how the unprecedented sample size to be collected by LSST will affect one of his particular interests, baryon acoustic oscillations (BAO). BAO are a tiny feature in the galaxy spatial correlation function that can be used to determine cosmological distances and hence dark energy properties. “By providing a sample of four billion well-measured galaxies extending above redshift of 2.5, the LSST will be able to measure BAO far better than any existing photometry surveys. Larger sample volume means smaller errors on large scales, and higher sample density means smaller errors on small scales. Because the LSST sample is so huge, one can divide the galaxies into sub groups and measure both the correlation within each group and cross correlations between the groups. In this way, there will be many cross checks, and more information can be extracted.”
Hu considers that discovery space to be the true value of a high quality survey like the LSST. “The most exciting discoveries will be those yet to be identified.”
A native of Shanghai, Hu envisions the rapid growth of the Chinese science and technology sector having a significant positive impact on projects like LSST. “There is so much room for growth in astronomy. For example, currently there are only four astronomy departments and a handful of astronomy-related centers and institutes in Chinese universities. I wouldn’t be surprised to see the size of the Chinese astronomy community double by the time LSST goes prime. I welcome the challenge of convincing more people and institutions to commit their time and other resources to the project.”
Article written by Robert McKercher and Hu Zhan
LSST is a public-private partnership. Funding for design and development activity comes from the National Science Foundation, private donations, grants to universities, and in-kind support at Department of Energy laboratories and other LSSTC Institutional Members:
Adler Planetarium; Brookhaven National Laboratory (BNL); California Institute of Technology; Carnegie Mellon University; Chile; Cornell University; Drexel University; Fermi National Accelerator Laboratory; George Mason University; Google, Inc.; Harvard-Smithsonian Center for Astrophysics; Institut de Physique Nucléaire et de Physique des Particules (IN2P3); Johns Hopkins University; Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) – Stanford University; Las Cumbres Observatory Global Telescope Network, Inc.; Lawrence Livermore National Laboratory (LLNL); Los Alamos National Laboratory (LANL); National Optical Astronomy Observatory; National Radio Astronomy Observatory; Princeton University; Purdue University; Research Corporation for Science Advancement; Rutgers University; SLAC National Accelerator Laboratory; Space Telescope Science Institute; Texas A & M University; The Pennsylvania State University; The University of Arizona; University of California at Davis; University of California at Irvine; University of Illinois at Urbana-Champaign; University of Michigan; University of Pennsylvania; University of Pittsburgh; University of Washington; Vanderbilt University
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