Professor
Teaching
I have taught a number of Astronomy courses for non-majors, majors, and graduate students while at Boston University.
Nearly every year for the past decade, I have taught AS109 Cosmology, an introductory course for mostly non-science majors. I have written a textbook for the course entitled From Nothing to Everything: The Story of Our Universe, the e-book version of which you can download without charge. My effort while writing and updating the book has been partially supported by a grant from the National Science Foundation.
During most years from 1989 to 2014, I taught in the Core Curriculum of the College of Arts and Sciences. The course was CC 105, The Evolution of the Universe and the Earth. I was the lead architect of the course, but a number of other professors contributed substantially. For many years, including 2013 and 2014, I was the lead instructor of the course. In 2013-2014 I also served as an associate director of the Core program. My textbook From Nothing to Everything: The Story of Our Universe served as the text for the course in 2013 and 2014. It is being adapted for the revised Core science courses.
I compose pop songs for the course and perform them in my lectures. I have recorded, and converted to MP3 format for downloading, a number of my science songs. I also perform the songs at astronomical meetings and parties, and at the annual College of Arts and Sciences/Core Curriculum Talent Review. I have composed and recorded several dozen other songs unrelated to science as well. Most of these are available at soundclick.com.
I am the proud recipient of a 2014 Metcalf Award for Excellence in Teaching by Boston University. Earlier, in 1998, I was honored with the Gitner Award for Distinguished Teaching by the College of Arts and Sciences. In 1999, Phi Beta Kappa, Epsilon chapter of Massachusetts at Boston University bestowed honorary membership on me. In 2003, I was given the honorary title of Distinguished Member of the National Society of Collegiate Scholars.
Research
My research group studies the extremely energetic plasma jets that emanate from a class of active galactic nuclei called “blazars” (radio-bright quasars and BL Lacertae objects, whose brightness tends to be highly variable and whose continuum spectra are non-thermal). The general consensus of the field is that ultra-massive (over a billion solar masses in some cases) black holes residing at the center of many galaxies power blazars as they accrete matter from their surroundings. The black holes swallow most of the gas and dust, but expel a small fraction in winds and jets along the rotation axes, at flow speeds very close to the speed of light. Such relativistic motions create illusions of faster-than-light speeds and beams the radiation emitted such that observers viewing the jet almost along the axis measure a very high brightness that varies on timescales as short as hours. The work of my group focuses on monitoring the changing brightness at radio, infrared, optical, X-ray, and gamma-ray frequencies, linear polarization at microwave, infrared, and optical frequencies, and the evolving structure of the jet on sub-milliarcsecond scales at millimeter wavelengths. Telescopes used currently include the Fermi Gamma-ray Space Telescope, the Very Long Baseline Array (VLBA), the Swift satellite observatory, Lowell Observatory Perkins Telescope, the Liverpool Telescope, Maria Mitchell Observatory, the Calar Alto Observatory, the Crimean Astrophysical Observatory, St. Petersburg State University telescope, and a number of other telescopes. In the recent past, we have used the Hubble Space Telescope, the Chandra X-ray Observatory, the Spitzer Space Telescope, the Rossi X-ray Timing Explorer, the Herschel Space Telescope, the Herschel Space Observatory, the XMM-Newton satellite, andthe INTEGRAL satellite.
Dr. Svetlana Jorstad from my research group and I are active members of the international Event Horizon Telescope (EHT) collaboration. The EHT is an international array of high-precision radio dishes that are arranged to observe together for about a week each year to act as a Very Long Baseline Interferometer at a wavelength of about 1 mm. The wide separation of the dishes and short wavelength provide an angular resolution of about 15 microarcseconds, sufficient to make images of the regions immediately surrounding the super-massive black holes at the center of our Milky Way Galaxy and of the relatively nearby (54 million light-years), giant elliptical galaxy M87. Results from the first set of observations (spring 2017) are expected to be released to the public in spring 2019.
Dr. Jorstad and I are also part of the Imaging X-ray Polarimetry Explorer (IXPE) mission, as members of the Technical Working Group on Blazars and Radiogalaxies, which I chair. IXPE is a joint mission of NASA and the Italian Space Agency designed to measure the polarization of cosmic sources at photon energies from 2 to 8 keV.
My group also engages in a theoretical program focused on the radiative processes that occur in the jets of blazars. The main goal is to provide models that can be used to interpret multifrequency monitoring observations of blazars in the hopes of figuring out the physics of jets: what produces them (what evidence can we obtain that it is really an accreting supermassive black hole?), what focuses and accelerates their flows to speeds very close to the velocity of light (twisting magnetic fields, gas pressure, or radiation pressure?), what accelerates the electrons to ultrarelativistic energies (shock waves – transverse to the jet axis or oblique? turbulence?), and what processes affect the emission (bends in the jet, accelerations in the flow, precession?).
Administration
From 2017 to 2019, I served as Associate Chair of the Astronomy Department at Boston University. In 2015-16, I served as Acting Chair of the Astronomy Department.
From 2011 to 2015, I served as the Director of the Institute for Astrophysical Research at Boston University. The IAR promotes research, education, and public outreach in astrophysics at BU. It also administers external funding grants in astrophysics as well as Boston University’s partnership with Lowell Observatory for use of the 1.8-meter-diameter Perkins Telescope outside Flagstaff, Arizona.
Between 2003 and 2007, I served as the Director of the Center for Excellence & Innovation in Teaching (CEIT) at Boston University. The CEIT operates a variety of programs designed to assist instructors who wish, for example, to improve their classroom performance, modernize their teaching techniques (e.g., through use of the web), or administer their courses more effectively.
From January 1999 to June 2003 I served as an Associate Dean in the College of Arts and Sciences at Boston University (half-time), with primary responsibility for faculty issues. Among my main duties were design and oversight of the College web site, running of orientation programs for new graduate teaching fellows and new “adjunct” faculty, coordination of continuing programs of language instruction for international graduate teaching fellows, identifying physical problems in classrooms that need to be fixed and acting as a liaison between instructors and Media Group, formation of a panel to determine recipients of College teaching awards, compilation of grading statistics in Arts and Sciences courses, and providing guidance to departmental chairs and to faculty.
I served as chairman of the Department of Astronomy from 1986 to 1997. During that time, the size of the academic faculty grew from 8 to 15 members, while that of the research faculty increased from 1 to 7.
Service: Committee Work
I have served on a number of professional committees. These include, among a number of others:
- Editorial Board of journal Vestnik of St. Petersburg (Russia) State University (2013-2018)
- NASA Fermi Space Telescope Users Group (2003-2007 and as chair 2009 – 2012)
- Panel on the future of VLBI in the US (2003)
- External oversight committee for the VERITAS telescope, which detects TeV-energy photons from cosmic sources via atmospheric Cherenkov radiation (2003 – present)
- National Academy of Sciences Decadal Survey of Astronomy and Astrophysics, Panel on Radio, Millimeter, and Submillimeter Astronomy (1998-2000 and 2004-05)
- National Science Foundation Advisory Committee on Astronomical Sciences (1988-92)
- NASA Compton Gamma Ray Observatory Users Committee (1995-98)
- AUI Visiting Committee for the National Radio Astronomy Observatory (1992-95, chair in 1995)
- National Radio Astronomy Observatory Users Committee (1984-87, 1990-93)
- ARISE Space VLBI (proposed NASA mission) Scientific Working Group (chair, 1998-present)
- Secretary-Treasurer, High Energy Astrophysics Division of the American Astronomical Society (1997-99)
- Associated Universities for Research in Astronomy board (1993-94)
I have served on a number of University committees as well, including the College of Arts & Sciences Academic Policy Committee (1988-90, chair in 1988-89, and again from 2017 to 2020)