Blazar Research at Boston University

Institute for Astrophysical Research

                                                                              People in the Blazar Research Group

1222+216 light curves1222+216 on
kpc scales

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: 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.

Above right: 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 Jansky Very Large Array. The Very Long Baseline Array is an instrument of the Long Baseline Observatory, which is a facility of the National Science Foundation operated by Associated Universities, Inc.
The Jansky Very Large Array is an instrument of the National Radio Astronomy Observatory, which is a facility of the National Science Foundation operated by Associated Universities, Inc.

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

VLBI Images of Selected Gamma-ray Bright Blazars at 86 GHz from the Global mm-VLBI Array (GMVA)

MOBPOL: Multi-Optical-Band Polarization of blazars: research program started in 2016

General Description of Our Research on Blazars    

TEMZ computer model for variability of flux, polarization, and spectral energy distribution of blazars            

Prof. Alan Marscher's textbook on cosmology for non-science majors: From Nothing to Everything: The Story of Our Universe

Fermi10 Blog (March 2018) on Gamma-ray Blazar Research, author's version
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, aka Alan Marscher

Dr. Alan Marscher                                      Dr. Svetlana Jorstad

Professor of Astronomy                                       Senior Research Scientist



Dr. Manasvita Joshi, Research Scientist Dr. Monasvita Joshi photo



        Mason Keck        

Mr. Mason Keck, Graduate Student


                                 Melissa Hallum   Ms. Melissa Hallum, Graduate Student


        Zachary Weaver

Mr. Zachary Weaver, Graduate Student

                                 Karen Williamson Ms. Karen Williamson, Research Technician


            Mr. Muhammad Zain Mobeen, 4th-year Undergraduate Student


Mr. John Hunter, 3rd-Year Undergraduate Student

        Karen Williamson

            Ms. Katya Leidig, 2nd-year Undergraduate Student

Photo of undergradudate Leeya Pressburger

Ms. Leeya Pressburger, 1st-Year Undergraduate Student



If you have any questions about the BU Blazar Research Group, please send e-mail to Prof. Marscher.