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:

http://www.nasa.gov/chandra
and
http://chandra.si.edu

Materials Science poster session

The NSF funded Materials Research Science & Engineering Center (MRSEC) received its 5 year review on Oct 11-12, 2012 when a panel of 5 scientists and 2 NSF officials visited Brandeis and kicked the tires of our Center. The highlight of the review was lunch between the panelists and 20 MRSEC graduates students and postdocs and the poster session, shown here, in which 30 posters describing research in the Center was presented to the panel. The four MRSEC thrusts were represented in the poster session: Active Matter, Chiral Self-Assembly, Oscillating Chemical Dynamics, and Confined Polymers, plus posters on our Seeds and Facilities. Join us again in Spring for our on-campus retreat.
 
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Memorandum of Understanding between the Brandeis Materials Research Science and Engineering Center (MRSEC) and the Robot Research Initiative (RRI), Chonnam National University, South Korea

 

Dr. Jong-Oh Park (left) and Dr. Seth Fraden pause in front of the MOU banner during the inauguration ceremony.

On August 10, 2012 Dr. Jong-Oh Park and Dr. Sukho Park, Director and Principal Investigator of the Robot Research Initiative (RRI), respectively, visited Brandeis as part of an inauguration ceremony of the Memorandum of Understanding (MOU) between the Brandeis Materials Research Science and Engineering Center (MRSEC) (Director: Seth Fraden, PhD) and the RRI (Director: Jong-Oh Park, Dr.-Ing). The RRI is a world leader in the field of robotics, focusing on microscale engineering applications and surgery, while the Brandeis MRSEC program focusses on biomaterials and active matter. The two institutions have agreed to work together to transform cutting-edge biophysical science into engineering applications for drug delivery.

Collaboration between the two institutions was first established on March 1, 2012, with a three-year subcontract (KRW  120,000,000 / yr) awarded to the MRSEC by the RRI for the development of micro-swimming robots based on synthetic cilia (PI: Dongshin Kim, co-PI: Zvonimir Dogic). Dr. Fraden welcomed the new Memorandum, saying that it would fortify the collaboration efforts of both institutions.

As part of the exchange program laid out by the MOU, Dr. Sukho Park is planning to visit Brandeis in 2013 to spend a year working on the development of micro-actuators based on microtubules and active hydrogels. There are opportunities for the exchange of students between our two universities.

Baskaran Wins NSF-CAREER award to pursue research on active fluids

Dr. Aparna Baskaran of the Physics Department has been awarded the prestigious CAREER grant from the National Science Foundation that is a highly competitive development grant for early career tenure track faculty members. This grant will fund the research ongoing in Dr. Baskaran’s group on dynamics in active materials. Active materials are a novel class of complex fluids that are driven out of equilibrium at the level of individual entities. Examples of such systems include bacterial suspensions, cytoskeletal filaments interacting with motor proteins and inanimate systems such as self-propelled phoretic colloidal particles. The theoretical challenge in understanding these systems lies in the fact that, unlike traditional materials, we no longer have the scaffold of equilibrium on which to base the theoretical framework.  At the practical front, these materials exhibit novel properties not seen in regular materials.  Further, they form the physical framework of biological systems  in that regulatory mechanisms modulate the mechanical properties of this material in response to environmental stimuli.  Dr. Baskaran’s research in this field will be done in collaboration with the groups of Dr. Michael Hagan, Dr. Zvonimir Dogic and Dr. Bulbul Chakraborty. It will enhance and complement the MRSEC research activities in the active materials thrust.

Figure Caption : Videos of example systems for active materials. A) A fish school exhibiting complex collective swimming. B) Swarming at the edge of an E. Coli Bacterial Colony. C) Cytoplasmic streaming inside the yolk of a fertilized cell.

Graduate Student Andreas Rauch awarded Outstanding Teaching Fellow in Physics

Graduate student Andreas Rauch has been awarded the Outstanding Teaching Fellow award in Physics based on his overall teaching excellence, student and course instructor evaluations, and letters from faculty.  According to Professor John Wardle, Chair of the Physics Department, “Andreas’ several years of teaching math in German schools has helped make him one of the best and most experienced Teaching Fellows I have known. This award is very well deserved.”  Andreas has been a teaching fellow in Physics 29a, Electronics Laboratory with Professor Larry Kirsch; Physics 25b, Astrophysics with Professor John Wardle; Physics 19b, Physics Laboratory II with Professor Zvonimir Dogic; and Physics 31a, Quantum Theory I with Professor Matthew Headrick.

Four other teaching fellows in the sciences will also be recognized at this year’s TF Award reception on May 6:

Mark Bezpalko (Chemistry)
Ryan Broderick (Mathematics)
Xiaochuan Cai (Chemistry)
Fan Zhao (Chemistry)

Keith Cheveralls ’09, Daniel Beller ’10, and Netta Engelhardt ’11 awarded NSF Graduate Research Fellowships

Former physics majors Keith Cheveralls ’09 and Daniel Beller ’10 and current physics major Netta Engelhardt ’11 have been awarded the prestigious National Science Foundation Graduate Research Fellowship. The fellowship recognizes and supports outstanding graduate students in the US who have demonstrated exceptional promise in science research. Keith is currently a first year graduate student at UC Berkeley; while at Brandeis he did his senior thesis with Professor Jane Kondev and was a co-author on a paper that appeared last year in the Proceedings of the National Academy of Sciences. Dan, a first year graduate student at the University of Pennsylvania, completed his senior thesis at Brandeis with Professor Zvonimir Dogic and Professor Robert Meyer.  Currently, Dan is conducting research on liquid crystals in the group of Professor Randall Kamien at UPenn. Netta is currently doing her senior thesis with Professor Matthew Headrick, and is planning to attend graduate school in physics next year.

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