Quasar Absorption Lines

Quasar Absorption Lines

COSMIC HISTORY IN A QSO RAINBOW:
Like a core sample drilling its way through the entire Universe itself, the light from a distant quasars interacts with the gaseous components between and within the galaxies over almost the whole history of the Cosmos (over the redshift range 0 to 5). This light sensitively records its every interaction with the gas in the form of absorption lines in the spectra of the quasars. These lines provide a wealth of information, allowing us to study the detailed physical conditions in the gas, such as its temperatures, ionization conditions, chemical content, and dynamical motions (kinematics). Since this record is preserved over the redshift range 0 to 5, we also can study the detailed cosmic evolution, including the evolution in the intensity of the ultraviolet background radiation and cosmic chemical evolution. In practice, then, astronomers who study quasar absorption lines are spectroscopists who analyze the spectral features using atomic physics and a broad knowledge of ionization physics, chemical yields from stars, and structure growth of the Universe.
Click here for a cartoon-like schematic of a quasar spectrum and its absorption lines.

PERSONNEL:
Individuals involved in this type of research are Prof. Jane Charlton, Dr. Chris Churchill, and Mr. Rajib Ganguly. Other local collaborators include Prof. Mike Eracleous, and Prof. Niel Brandt, as well as several undergraduate students. You also can check out the Home Page of the Penn State Quasar Absorption Line Group. A synopsis of Research Highlights on the so-called Mg II absorbers is also available.

SLIDE SHOWS:
Peruse our AAS poster papers...

(1) Jane Charlton's Introduction to the Field, which was an Invited talk at the Winter 1997 AAS Meeting Toronto.

(2) The discovery of a population of "weak" Mg II absorbers.

(3) The properties of the population of "weak" Mg II absorbers.

(4) Low Metallicity Lyman alpha Clouds.

(5) The High Ionization Components of Galactic Gas: C IV Absorption.

(6) The Multiphase Ionization in Three Galaxies at z~1.

FUTURE PLANS:
In the coming years, there are a plethora of opportunities for graduate students and undergraduate students alike, including Ph.D dissertaion projects and senior thesis projects. At Penn State, we will be in a unique position in our field for the next half decade due to our access and planning with the 9-meter Hobby Eberly Telescope (HET).
Future plans are centered around a large survey of high redshift (2 < z < 4) Mg II absorbers using a new near-IR spectrograph, the JCAM, currently being built at Penn State for the HET. With JCAM, we can also obtain the infrared spectra of high redshift galaxies (useful because this is the observed band to which many of the strong, important, diagnostic features are redshifted). Studies of the metallicity evolution in the so-called damped Lymna-alpha systems (DLAs) can also be studied to z=5 using Cr II and Zn II absorption lines. We also plan to use the high resolution spectrograph, HRS, on the HET for many projects, including a full-blown survey of the high ionization kinematics, ionization, and chemical conditions in ~150 galaxies from z=1 to z=4 covering the epochs over which the bulk of the activity in galaxy evolution is thought to have occured.

WANT TO LEARN MORE?
If you have questions about opportunities in quasar absorption line research at Penn State, please feel free to contact Prof. Jane Charlton (charlton@astro.psu.edu) or Dr. Chris Churchill (cwc@astro.psu.edu)

Back to the Penn State Astronomy Research Page.

Web page by Chris Churchill and Jane Charlton
Last update: December 1999