Blazar Research at Boston University
Institute for Astrophysical Research
People in the Blazar Research Group
Above left: Movie of the jet of gamma-ray bright quasar 1222+216 (or 4C21.35), at a redshift of 0.435 (distance of 3.8 billion light-years), so that 0.5 mas (milli-arcseconds) corresponds to 9.2 light-years. The images used to make the movie are from the Very Long Baseline Array. Colors indicate brightness. Although we think that the jet flows continously from near the black hole (which is invisible and located near the bottom of the frame), "blobs" of brightness appear and move down the jet (at speeds that appear to be faster than light - just an illusion) as the jet becomes bright in gamma rays (as observed by NASA's Fermi Gamma-ray Space Telescope) and at other frequencies.
Above middle: The same quasar but on scales of tens of thousands of light-years, showing how the jet twists.We think that the jet is really coming almost right at us, so the bends appear more dramatic than they are in 3D. False color: X-ray image from NASA's Chandra X-ray Observatory; contours: 1.4 GHz radio image from the Very Large Array. The Very Long Baseline Array and the Very Large Array are instrumenst of the National Radio Astronomy Observatory, which is a facility of the National Science Foundation operated by Associated Universities, Inc.
Above right: Brightness vs. time. Top panel: Gamma-ray (blue: Fermi; yellow: MAGIC and VERITAS); bottom panel: visible light. Red vertical dashed lines mark times when a new blob first appears in the jet.
Project VLBA-BU-BLAZAR: Roughly Monthly VLBA Images of Gamma-Ray Bright Blazars at 43 GHz with Data Files and Graphs of Gamma-ray and Visible-light Brightness Plus Visible-light Polarization vs. Time
General Description of Our Research on Blazars
Prof. Alan Marscher's textbook on cosmology for non-science majors: From Nothing to Everything: The Story of Our Universe
Prof. Alan Marscher's presentation on Jets from Black Holes in Quasars at the Northeast Astronomy Forum on Saturday April 18, 2009 (for anyone interested in black holes & quasars)
Original Science Songs by Cosmos II (including international hit "Superluminal Lover"), aka Alan Marscher
Press Release: Graduate student Nicholas MacDonald won the prize for best student talk at the May 2015 meeting of the Canadian Astronomical Society in Hamilton, Ontario. His talk on his model for "orphan" gamma-ray flares from a blob of plasma passing through a region of strong emission in the sheath of a blazar jet was accompanied by a press release.
Dr. Alan Marscher Dr. Svetlana Jorstad
Professor of Astronomy Senior Research Scientist
Dr. Manasvita Joshi, Senior Postdoctoral Associate
Dr. Mahito Sasada, Postdoctoral Fellow
Mr. Michael Malmrose, Graduate Student
Mr. Nicholas MacDonald, Graduate Student
Mr. Mason Keck, Graduate Student
Ms. Karen Williamson, Researcher
Mr. Vishal Bala, 3rd-year Undergraduate Student
Ms. Nicole Rider, Summer Undergraduate Student from U. California, Santa Cruz
Dr. Ivan Agudo, former Postdoctoral Research Associate & current Visiting Scientist
If you have any questions about the BU Blazar Research Group, please send e-mail to Prof. Marscher.