Martin Gaskell

Theory Group and Extragalactic Group


Contact Information:



Research Interests


    My main area of study is the theory and observations of the violent processes going on around supermassive black holes in quasars and active galactic nuclei (AGNs).  These black holes have masses of up to 10 billion times the mass of our sun, and include the most powerful, compact, steady-state energy sources in the universe.  The principle goals of my research are (a) to understand what AGNs are like and just how they generate their tremendous energy, and (b) to understand the cosmological evolution of supermassive black holes and their co-relationships with their host galaxies.  This research involves things ranging from theoretical calculations on computers to getting data from the Hubble Space Telescope, a variety of X-ray satellites (such as Chandra, RXTE, and Swift), and from all sorts of ground-based telescopes.  One of my long-term interests has been using the variability of the radiation from AGNs to probe what is going on around the supermassive black holes, and in doing this I work with many astronomers around the world.  Other things I have worked on in addition to supermassive black holes include supernova explosions, stellar populations in normal galaxies, and astronomical instrumentation.


For a non-technical description of some of my supermassive black hole research click here.



    B.S. - Edinburgh University, Scotland

    M.S. & Ph.D. - University of California at Santa Cruz


Recent published and submitted papers (2009-2010):

(present or former student co-authors are followed by an asterisk)


Gaskell, C. M. Off-Axis Energy Generation in Active Galactic Nuclei: Explaining Broad-Line Profiles, Spectropolarimetric Observations, and Velocity-Resolved Reverberation Mapping, submitted to Astrophysical Journal.


Gaskell, C. M. An Improved [O III] Line Width to Stellar Velocity Dispersion Calibration: Curvature, Scatter, and Lack of Evolution in the Black-Hole Mass Versus Stellar Velocity Dispersion Relationship, submitted to Astrophys. J.


Gaskell, C. M. & Goosmann, R. W. Line Shifts, Broad-Line Region Inflow, and the Feeding of AGNs, submitted to Astrophys. J.


Gaskell, C. M., Klimek, E. S.*, and Nazarova, L. S. NGC 5548: the AGN Energy Budget Problem and the Geometry of the Broad-Line Region and Torus, submitted to Astrophys. J.


Gaskell, C. M. and Benker, A. J.* Reddening and Ultraviolet Extinction Curves from Hubble Space Telescope Spectra, submitted to Astrophys. J.


Gaskell, C. M., Goosmann, R. W., Merkulova, N. I., Shakhovskoy, N. M., and Shoji, M.* Discovery of Polarization Reverberation in NGC 4151 submitted to Astrophys. J.


Gaskell, C. M. The origin of the relationship between black hole mass and host galaxy bulge luminosity in The First Stars and Galaxies: Challenges for the Next Decade, AIP Conf. Proc. 1294, 261 (2010).


Gaskell, C. M. Accurate AGN Black Hole Masses and the Scatter in the MBH-Lbulge Relationship, in Co-Evolution of Central Black Holes and Galaxies, IAU Symp., 267, 203 (2010).


Denney, K. D.*, . . . Brokofsky, D. J., . . . Doroshenko, V. T., . . . Efimov, Y. S., . . . Gaskell, C. M., . . . Hedrick, C. H.*, . . . Klimek, E. S.*, Kruse, A. K.*, . . . Petersen, E. A.*, . . . Sergeev, S. G. . . . Watkins, A. E.*, et al. Reverberation Mapping Measurements of Black Hole Masses in Six Local Seyfert Galaxies Astrophys. J., 721, 7111 (2010).


Gaskell, C. M. Close supermassive binary black holes, Nature, 463, E1 (2010).


Gaskell, C. M. What broad-line regions tell us about how active galactic nuclei work (invited review) New Astron. Rev., 53, 140 (2009)


Chatterjee, R.* , Marscher, A. P., . . . Benker A. J.*, . . . Brokofsky, D. J.*, Campbell, J. S.*, Chonis, T. S.* , Gaskell, C. M., . . . Hedrick, C. H.*, . . . Klimek, E. S.*, Kruse, A. K.*, Shoji, M.*, Petersen, E. A.*, Peterson, B. W.* . . . Watkins, A. E.*, and Wheeler, K.* The Disk-Jet Connection in the Radio Galaxy 3C 120, Astrophys. J., 704, 1689 (2009).


Denney, K. D.*, Peterson, B. M., . . . Brokofsky, D. J.*, . . . Gaskell, C. M., Hedrick, C. H.*, . . . Klimek, E. S.*, Kruse, A. K.*, . . . Petersen, E. A., . . . Watkins, A. E.*, et al., Diverse Broad Line Region Kinematic Signatures From Reverberation Mapping, Astrophys. J. Letts., 704, L80 (2009).


Denney, K. S.*, . . . Brokofsky, D. J.*, . . . Gaskell, C. M., Hedrick, C. H.*, . . . Klimek, E. S.*, Kruse, A. K.*, . . . Petersen, E. A.*, . . . Watkins, A. E.*, et al. A Revised Broad-Line Region Radius and Black Hole Mass for the Narrow-Line Seyfert 1 NGC 4051, Astrophys. J., 702, 1353 (2009).


Bochkarev, N. G. & Gaskell, C. M. The Accuracy of Supermassive Black Hole Masses Determined by the Single-Epoch Spectrum (Dibai) Method Astron. Letts. 35, 287 (2009)


Breedt, E.*, Arevalo, P., McHardy, I. M., Uttley, P., Sergeev, S. G., Minezaki, T., Yoshii,Y., Gaskell, C. M., Cackett, E., Horne, K., & Koshida, S., Long-Term Optical and X-ray Variability of the Seyfert Galaxy Markarian 79 Mon. Not. Roy. Astron. Soc.394, 427 (2009).


For older publications and a more complete listing of recent publications see: ADS


Teaching - Ast. 301 webpage



- Fellow of Royal Astronomical Society (RAS).

- Member of Space and High Energy Astrophysics Commission (Commission 44) of the International Astronomical Union (IAU).

- Member American Astronomical Society (AAS).

- Member High Energy Astrophysics Division (HEAD).

- Five-time finalist for Association of Students of the University of Nebraska annual Outstanding Educator Award

- Nine-time recipient of University of Nebraska Teaching Council and Parents Association Certificate of Recognition for Contributions to Students.

- Mortar Board Professor of the Month (twice)

- Kappa Delta Educator of the Month

- Listed in Who's Who, Who's Who of American Men and Women of Science, and Who's Who of American Educators


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