David Waltz Fellowship

According to BrandeisNOW, Xiru Zhang, PhD ’91, has made a lead gift to help establish the David Waltz Fellowship at Brandeis in hopes of broadening the participation of women and minorities in the field of artificial intelligence. The gift is to honor Waltz, who died in March 2012, as a nurturing mentor, an inspiring colleague, a giving co-worker and a longtime friend. Waltz and Zhang worked together for six years Zhang pursued his doctorate in computer science (the first awarded in computer science from Brandeis, simultaneously interacting as professor-student at Brandeis and as senior scientist-research scientist at Cambridge-based Thinking Machines.

“No one had a greater influence on my academic and science research career than David Waltz,” says Zhang, “He was my mentor,  and he was also my friend.”

Read more at BrandeisNOW.

Lovett, alumni named AAAS Fellows

Professor of Biology Susan T. Lovett was elected a fellow of the American Association for the Advancement of Science. AAAS fellows will be recognized for their contributions to science and technology on 16 February 2013 during the AAAS Annual Meeting in Boston. Brandeis alumni elected as fellows are Steve Alexander (PhD ’76), Patrick Casey (PhD ’86), Rui-Ming Xu (PhD ’90) and Charles Brenner (postdoc 93-96).

Lovett, who works on DNA repair mechanisms in bacteria, has recently been profiled on Brandeis NOW.

Med School and Grad School in the Lone Star State

Wensink lab alum Mien-Chie Hung (PhD ’84), who is currently Ruth Legett Jones Distinguished Chair at  The University of Texas MD Anderson Cancer Center, will give seminar on Monday, Dec 3 at noon in Rosenstiel 118 on “Novel signaling pathways in cancer cells and their crosstalk to predict resistance for target therapy“.  He will also meet with interested students on Monday Dec. 3 in the Alumni Lounge in Usdan at 7 PM; there will be pizza.   He will talk with undergrads, prospective grad and med students about medical schools and graduate schools in Texas Medical Center including MD Anderson, UT Health Science Center and Baylor.

Record-Setting X-ray Jet Discovered

X-ray jet

X-ray jet from quasar GB 1428, located 12.4 billion light years from Earth. (X-ray: NASA/CXC/NRC/C.Cheung et al; Optical: NASA/STScI; Radio: NSF/NRAO/VLA)

On November 28, NASA posted a press release announcing the record breaking discovery of an x-ray emitting jet in a quasar at a distance of 12.4 billion light years from Earth. The discovery is published in the Astrophysical Journal Letters, and the lead author is C. (Teddy) Cheung (Brandeis PhD 2004). Co-authors include Doug Gobeille (Brandeis PhD 2011), Brandeis professor of astrophysics John Wardle, and colleagues from the Harvard-Smithsonian Center for Astrophysics. Teddy Cheung made the x-ray image, using the orbiting Chandra X-ray observatory, and Doug Gobeille made the radio image as part of his PhD research at Brandeis using the 27 antennas of the Very Large Array in New Mexico.

A jet of X-ray emitting plasma from a supermassive black hole 12.4 billion light years from Earth has been detected by NASA’s Chandra X-ray Observatory. This is the most distant X-ray jet ever observed and gives astronomers a glimpse into the explosive activity associated with the growth of supermassive black holes in the early universe. The jet was produced by a quasar named GB 1428+4217, or GB 1428 for short. Giant black holes at the centers of galaxies can pull in matter at a rapid rate producing the quasar phenomenon. The energy released as particles fall toward the black hole generates intense radiation and powerful beams of high-energy particles that blast away from the black hole at nearly the speed of light. These particle beams can interact with magnetic fields or ambient photons to produce jets of radiation.

“We’re excited about this result not just because it’s a record holder, but because very few X-ray jets are known in the early universe,” said Teddy Cheung of the National Academy of Sciences, resident at the Naval Research Laboratory in Washington DC, and lead author of the paper describing these results.

As the electrons in the jet fly away from the quasar, they move through a sea of background photons left behind after the Big Bang. When a fast-moving electron collides with one of these so-called cosmic microwave background photons, it can boost the photon’s energy into the X-ray band.

“Since the brightness of the jet in X-rays depends, among other things, on how fast the electrons are moving away from the black hole, discoveries like the jet in GB 1428 tell us something about the environment around supermassive black holes and their host galaxies not that long after the Big Bang,” said co-author Lukasz Stawarz from the Japan Aerospace Exploration Agency, in Kanagawa, Japan.

Because the quasar is seen when the universe is at an age of about 1.3 billion years, less than 10% of its current value, the cosmic background radiation is a thousand times more intense than it is now. This makes the jet much brighter, and compensates in part for the dimming due to distance.

“We’re lucky that the universe gives us this natural amplifier and lets us detect this object with relatively short exposures,” said co-author Aneta Siemiginowska, of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, “Otherwise we might miss important physical processes happening at very large distances from Earth and as far away as GB 1428.”

While there is another possible source of X-rays for the jet — radiation from electrons spiraling around magnetic field lines in the jet — the authors favor the idea that the cosmic background radiation is being boosted because the jet is so bright.

Prior to the discovery of the jet in GB 1428, the most distant X-ray jet known was 12.2 billion light years away, and another is located at about 12 billion light years, both discovered by authors of the GB 1428 paper. A very similar shaped jet in GB 1428 was also detected in radio waves with the NSF’s Very Large Array (VLA).

The particle beams that produce these three extremely distant X-ray jets appear to be moving slightly more slowly than jets from galaxies that are not as far away. This may be because the jets were less energetic when launched from the black hole or because they are slowed down more by their environment.

The researchers think the length of the jet in GB 1428 is at least 230,000 light years, or about twice the diameter of the entire Milky Way galaxy. This jet is only seen on one side of the quasar in the Chandra and VLA data. When combined with previously obtained evidence, this suggests the jet is pointed almost directly toward us. This configuration would boost the X-ray and radio signals for the observed jet and diminish those for a jet presumably pointed in the opposite direction.

Observations were also taken of GB 1428 with a set of radio telescopes at different locations around the Earth that allows details to be resolved on exceptionally small scales. They revealed the presence of a much smaller jet, about 1,900 light years long, which points in a similar direction to the X-ray jet.

This result appeared in the September 1st, 2012 issue of The Astrophysical Journal Letters. Other co-authors of the paper are Doug Gobeille from University of South Florida in Tampa, FL; John Wardle from Brandeis University in Waltham, MA; and Dan Harris and Dan Schwartz from the Harvard-Smithsonian Center for Astrophysics.

NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra Program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

More information, including images and other multimedia, can be found at:


Brandeis mathematicians in inaugural class of AMS fellows

Department members and emeritus professors named as AMS fellows.

The Math department website notes that Professors Ruth Charney, Ira Gessel, and Kiyoshi Igusa, along with emeritus professors Edgar Brown, David Buchsbaum, Harold Levine, Richard Palais, and Gerald Schwarz, have been named to the inaugural group of Fellows of the American Mathematical Society.  According to the description on the AMS website, the “Fellows of the American Mathematical Society program recognizes members who have made outstanding contributions to the creation, exposition, advancement, communication, and utilization of mathematics.” The first class was announced earlier this month. Among Brandeis alumni in this first batch of fellows, we noted Karen Uhlenbeck (PhD ’68), Jill Mesirov (PhD ’74), Ralph Cohen (PhD ’78), and Ulrike Tillmann ‘85.

COSI High Tech Alumni Leadership Conference on Nov. 2

The Brandeis Alumni Association is hosting the first-ever Computer Science (COSI) High Tech Alumni Leadership Conference. An exciting day has been planned with entrepreneurs, venture capitalists, technical directors, lead engineers, and academics who will discuss the latest advances, trends and innovations. Adam Cheyer ’88, co-founder of Siri Inc. and director of engineering at Apple, will open the program and receive the inaugural Brandeis Computer Science Entrepreneur of the Year award. For a full list of speakers, see http://alumni.brandeis.edu/web/special_programs/cosi_brandeis/cosi_speaker.html

COSI High Tech Alumni Leadership Conference
Friday, November 2, 2012
Sachar International Center, Wasserman Cinematheque
8:30 a.m.- 5:30 p.m.

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