Elizabeth KlimekGraduate Student NMSUAstronomy
Since coming to NMSU, I have been a member of Chris Churchill’s Quasar Absorption Line Group.
In the grand scheme of things, I am interested in galaxy formation and evolution. In particular, I am interested in the origin and nature of coronal gas surrounding star-forming galaxies like the Milky Way.
The Baryon Cycle in High Redshift Galaxies:
I am currently working on my dissertation project, which uses cosmological simulations to study the relationship between processes in the disk and in the surrounding circumgalactic medium (CGM) of high redshift (2<z<4) galaxies. This redshift range is interesting because it is the time period leading up to the most active period of star formation in galaxies.
Understanding the cycle of baryons during this time is important for understanding galaxy formation and evolution. Gas accretion from the intergalactic medium (IGM) must pass through and interact with the multiphase circumgalactic medium (CGM), which makes up the gaseous halo component of a galaxy. The CGM itself can also serve as a reservoir of gas that could eventually cool and accrete onto the disk. Stellar feedback due to star formation drives winds that carry metals away from the disk and into the halo. If the wind speeds exceed the escape velocity of the galaxy, the outflowing gas will enrich the the IGM. However, if the wind speeds are below the escape speed, the outflowing material could either linger in the halo or rain back down onto the disk in a fountain type flow. The fate of the outflow gas thus has consequences for the evolution of the disk.
Photoionization Modeling of the Intergalactic Medium (IGM):
In a collaboration with Daniel Ceverino, I employed the photoionization code Cloudy to calculate heating and cooling rates within plane parallel cloud models having a given hydrogen density, temperature, and thickness. The resulting grid of models will be incorporated into future cosmological hydrodynamical simulations run with the ART code.
I also used Cloudy to explore the effects of shielding on the observed column densities of MgII, CIV, OVI, and FeII. Observed column densities are combined with photoionization modeling to estimate the metallicities of absorbing gas clouds in the IGM. However, most models do not account for shielding by material that is in the proximity of the observed clouds. The presence of shielding means that the cloud is exposed to a softened version of the Haardt-Madau UV background. If shielding is present but is not accounted for, the metallicity of the observed cloud wll be underestimated relative to unshielded absorbers.
Variability of Active Galactic Nuclei (AGN):
As an undergraduate at the University of Nebraska I was fortunate to have many opportunities to get involved with research and explore my interests. I started off by creating magnetic images of thin films by day and making photometric observations of AGNs by night. Ultimately deciding that the latter was more exciting, I decided to continue my AGN research with Dr. Martin Gaskell after graduating with my bachelor’s degree. While working towards my physics masters, I participated in large multi-wavelength monitoring campaigns of several AGNs by obtaining optical photometric observations. One of the purposes of such monitoring campaigns is to understand the relationship between variability in different wavelength regimes, most notably the optical, UV, and X-rays.
For my thesis project, I searched for optical microvariability (on the timescale of hours) in Narrow Line Seyfert 1 (NLS1) galaxies. I focused on this specific type of AGN because NLS1s are known to exhibit rapid, large amplitude variability in the X-rays. In stark contrast to this behavior, however, I found that intranight optical variability in these objects is rare and of low amplitude. My results suggest that the optical and the X-ray continuum each have separate production mechanisms.
Other Astronomical Interests
Although my graduate work by necessity focuses on one specific topic, I am fascinated by just about all things astronomy. Ever since the Huygens probe landed on Titan, however, I have to say that I have become a tad bit obsessed with this moon. It’s on my list of favorite objects, right behind accreting supermassive black holes and galaxy halos!
A Revised Broad-Line Region Radius and Black Hole Mass for the Narrow-Line Seyfert 1 NGC 4051
K. D. Denney et al. 2009, ApJ, 702, 1353
NGC 5548: The AGN Energy Budget Problem and the Geometry of the Broad-Line Region and Torus
C. M. Gaskell, E. Klimek, & L. Nazarova, submitted to ApJ
X-ray/ultraviolet Observing Campaign of the Markarian 279 Active Galactic Nucleus Outflow: A Close Look at the Absorbing/Emitting Gas with Chandra-LETGS
E. Costantini et al. 2007, A&A, 461, 121
Optical Variability of Narrow-Line Seyfert 1 Galaxies
E. Klimek, C. M. Gaskell, & C. H. Hedrick 2004, ApJ, 609, 69
Variability Of Active Galactic Nuclei From The Optical To X-Ray Regions
C. M. Gaskell & E. Klimek 2003, A&AT, 22, 4
Multiwavelength Monitoring of the Narrow-Line Seyfert 1 Galaxy Arakelian 564. III. Optical Observations and the Optical-UV-X-Ray Connection
O. Shemmer et al. 2001, ApJ, 561, 162
A Spectroscopic and Photometric Study of Short-Timescale Variability in NGC 5548
M. Dietrich et al. 2001, A&A, 371, 79
July 23-24, 2011: Center for Astronomy Education (CAE) Legacy Program Teaching Excellence Workshop
June 25-27, 2008: NASA Astrobiology Workshop
January 3-8, 2010: American Astronomical Society meeting
Poster: “Effects of Shielding on Metallicity Estimates in QSO Absorption Line Systems”
Klimek, E. & Churchill, C. W.
June 14-16, 2004: AGN Variability from X-Rays to Radio Waves (Conference), Crimea, Ukraine, Optical Continuum and Line Variability of NLS1s
Klimek, E., Gaskell, C., & Hedrick, C
June 14-16, 2004: AGN Variability from X-Rays to Radio Waves (Conference), Crimea, Ukraine, Optical Variability of the Three Brightest Nearby Quasars
Gaskell, C. M. et al.
January 2004: American Astronomical Society meeting, Optical Variability of Narrow-Line Seyfert 1 Galaxies
Klimek, E., Gaskell, C. M. & Hedrick, C. H.
January 2004: American Astronomical Society meeting, Optical Variability of Two High-Luminosity Radio-Quiet Quasars, PDS 456 and PHL 1811
Gaskell, C. M. et al.
January 2002: American Astronomical Society meeting, Optical Variability of the Narrow-Line Seyfert 1 Galaxy Akn 564 on Timescales from Hours to Years
Gaskell, C. M. et al.