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Eileen Theresa Meyer

Eileen Meyer
Contact Information

meyer@umbc.edu
410-455-2534
Physics, Rm 312

Academic Page

Title

Assistant Professor

Education

Ph.D. Physics – Rice University (Houston, TX), 2012
M.S. Physics – Rice University (Houston, TX), 2008
B.S. Astrophysics – Rice University (Houston, TX), 2005

Previous Experience

Dr. Meyer was previously a postdoctoral fellow at the Space Telescope Science Institute (STScI) in Baltimore, MD, which manages the Hubble Space Telescope (HST) and upcoming James Webb Space Telescope. While at STScI, Dr. Meyer worked with the HST Proper Motions group to measure, for the first time, the superluminal motions of several nearby extragalactic jets as seen by Hubble. She also used the Very Large Array (VLA), HST, the Chandra X-ray observatory, and the Fermi gamma-ray telescope to measure the speed of jets from black holes.

Professional Interests

One of the major problems in astronomy today is understanding how galaxies first formed and evolved through cosmic time to produce the Universe as we see it today. We now know that most, probably all, massive galaxies have a super-massive black hole at their centers. As an observational astronomer, Dr. Meyer is interested in the general question of how the phenomena related to the growth of these black holes affect their wider environment. In particular, she is working to understand the physics and impact of the relativistic jets associated with the most massive black holes, which almost certainly have a major effect on their host galaxies and clusters throughout their lifetimes. At present, her work is concentrated on two fronts – analyzing the kinematics of nearby jets imaged by HST over the past two decades, and using multiwavelength (radio through gamma-ray) data to determine the emission mechanism in powerful quasar jets, a question which has huge implications for our accounting of the radiative output of these jets at TeV energies. TeV emission from jets has been suggested as a means of solving the ‘missing dwarf galaxy problem’ and may point to jets being a significant contributor to reionization.

In the field of jet proper-motions, Dr. Meyer has used archival HST imaging to map the complete velocity field of the jet in M87, showing for the first time the helical alignment of velocity vectors in the outer jet (Meyer et al. 2013, ApJ 744, L21). Dr. Meyer also won observing time on HST in cycles 21 and 22 to measure the proper motions of other nearby jets. To highlight just the most interesting of these results so far, observations of 3C 264 have revealed the first direct evidence of colliding knots leading to particle acceleration, a validation of the long-unconfirmed internal shock hypothesis (Figure at right; to appear in Nature in 2015). In the next stage of this work, Dr. Meyer and colleagues are pushing the boundaries of proper-motions measurement to jets as distant as 500 Mpc. This is enabled by a new image registration technique based on faint background galaxies

This question of the emission mechanism for high-energy radiation from jets is not a minor detail of jetted AGN. The two competing models for the X-ray emission of powerful quasar jets – synchrotron or inverse Compton – imply radically different physical conditions, and in turn, radically different environmental effects. Working with Dr. Georganopoulos and colleagues at STScI, Dr. Meyer has shown that the inverse Compton model can be ruled out using upper limits from the Fermi gamma-ray telescope, in conjunction with high-resolution radio, infrared, and optical/UV imaging (Meyer et al. 2014, ApJ 780, L27). This initial result has paved the way for new observations with the VLA, HST, and Chandra approved in the most recent cycles, which should lead us to solve the long-standing question of how jets produce X-ray emission. High-resolution imaging will be key in unraveling the mystery of outflows from black holes, and instruments like JWST, HST, and WFIRST will be at the forefront of these efforts.

Selected Publications

A kiloparsec-scale Internal Shock Collision in the Jet of a Nearby Radio Galaxy Eileen T Meyer, M. Georganopoulos, William B. Sparks, Eric Perlman, Roeland P. van der Marel, Jay Anderson, Sangmo Tony Sohn, John Biretta, Colin Norman, Marco Chiaberge
Nature (in press, 2015)

Ruling out IC/CMB X-rays in PKS 0637-752 and the Implications for TeV Emission from Large-Scale Quasar Jets
Eileen T. Meyer, M. Georganopoulos, W. B. Sparks, Leith Godfrey, Jim Lovell, Eric Perlman
The Astrophysical Journal (in press, 2015)

Fermi Rules Out the IC/CMB Model for the Large Scale Jet X-ray Emission of 3C 273
Eileen T. Meyer & Markos Georganopoulos.
The Astrophysical Journal Letters 780:2, L27 (2014)

Polarization Diagnostics for Cool Core Cluster Emission Lines
W. B. Sparks, J. E. Pringle, R. F. Carswell, G. M. Voit, M. Donahue, M. Cracraft, Eileen T. Meyer, J.H. Hough, N. Manset.
The Astrophysical Journal 780:1, 66 (2014)

Optical Proper Motion Measurements of the M87 Jet: New Results from the Hubble Space Telescope
Eileen T. Meyer, W. B. Sparks, J. A. Biretta, Jay Anderson, Sangmo Tony Sohn, Roeland P. van der Marel, Colin Norman, Masanori Nakamura.
The Astrophysical Journal Letters 744:2, L21 (2013)

A Universal Scaling for the Energetics of Relativistic Jets from Black Hole Systems
R. S. Nemmen, M. Georganopoulos, S. Guiriec, Eileen T. Meyer, N. Gehrels, R. M. Sambruna.
Science 338:6113, pp. 1445 (2012)

Collective Evidence for Inverse Compton Emission from External Photons in High-power Blazars
Eileen T. Meyer, G. Fossati, M. Georganopoulos, M. L. Lister.
The Astrophysical Journal Letters 752:1, L4 (2012)

γ-Ray and Parsec-scale Jet Properties of a Complete Sample of Blazars From the MOJAVE Program.
M. L. Lister, M. Aller, H. Aller, T. Hovatta, K. Kellermann, Y. Y. Kovalev, Eileen T. Meyer, A. B. Pushkarev, E. Ros & the MOJAVE Collaboration.
The Astrophysical Journal 742:1, 27 (2011)

From the Blazar Sequence to the Blazar Envelope: Revisiting the Relativistic Jet Dichotomy in Radio-loud Active Galactic Nuclei.
Eileen T. Meyer, G. Fossati., M. Georganopoulos, M. L. Lister.
The Astrophysical Journal 740:2, 98 (2011)

A series of optical images taken by Hubble of a 1300 lightyear-long jet from the super-massive black hole at the center of nearby elliptical galaxy NGC 3862 reveals dramatic changes over 20 years. The bright central knot in the jet appears to move with a speed seven times the speed of light, and is in the process of colliding with a slower-moving downstream knot. The subsequent brightening of both knots indicates that particle acceleration may be taking place as a result of an internal shock collision, a model which has been proposed to explain high-energy radiation from jets of black holes from a few to billions of times the mass of our sun. (from Meyer et al., 2015, Nature)

A series of optical images taken by Hubble of a 1300 lightyear-long jet from the super-massive black hole at the center of nearby elliptical galaxy NGC 3862 reveals dramatic changes over 20 years. The bright central knot in the jet appears to move with a speed seven times the speed of light, and is in the process of colliding with a slower-moving downstream knot. The subsequent brightening of both knots indicates that particle acceleration may be taking place as a result of an internal shock collision, a model which has been proposed to explain high-energy radiation from jets of black holes from a few to billions of times the mass of our sun. (from Meyer et al., 2015, Nature)