Paul Nunez Thesis Defense 06/4/12

Thesis Defense

Paul Nuñez

Monday, June 4, 2012
3:00pm (334 JFB)

Title: Towards Optical Intensity Interferometry for High Angular Resolution Stellar Astrophysics


Most stars are detected as point sources, and recent developments in high angular resolution astronomy have enabled to image stars as extended objects with complex atmospheres and circumstellar environments. However, most neighboring stars are still beyond the angular resolution reach of current observatories.

Atmospheric Cherenkov Telescopes (ACT) are used in gamma-ray astronomy to investigate violent phenomena in the universe. However, this technique can also be used for stellar astrophysics on some isolated sources. Such is the case with the Xray binary LSI+61 303 which was detected in the TeV range. A gamma-ray attenuation model is developed and applied it to this system. This models allows to place constraints on fundamental properties of the system. However, a much better understanding of this system, and more so of nearby bright stellar systems, could be obtained with high angular resolution techniques.

Light detectors such as ACT, can be used as intensity interferometry receivers in the visible band (400 nm). Optical stellar intensity interferometry with air Cherenkov telescope arrays, composed of nearly 100 telescopes, will provide means to measure fundamental stellar parameters and also open the possibility of model-independent imaging. The phase of the complex degree of coherence is not measured in this technique. However, several model-independent phase reconstruction techniques have been developed. Here we implement a Cauchy-Riemann based algorithm to recover images from simulated data. We find that stellar images can be accurately reconstructed, and results are further improved with post-processing routines.

Finally, experimental efforts to measure intensity correlations are expounded. The functionality of analog and digital correlators is demonstrated. Intensity correlations have been measured for a simulated star emitting pseudo-thermal light, resulting in angular diameter measurements. The StarBase observatory, consisting of a pair of 3 m telescopes separated by 23 m, is described


Transit of Venus

Transit of Venus
Dr. Ben Bromley

Location: Skaggs Biology Building (ASB) Auditorium, Room 220 at the University of Utah
View Map

Talk Date: June 4, 2012, 7:00pm

Venus Transit Date: June 5, 2012

Free event open to the public.

On June 5, 2012, our sister planet Venus will pass in front of the Sun. Venus’ silhouette will appear on the Sun’s face, just for a few hours. This “transit” event is rare! It won’t happen again for more than a century. But astronomers now see distant planets transiting their own stars every day. Come learn how Venus’ transit first helped astronomers map the Solar System and find out about the mysterious “Black Drop.” Hear about the trials and tribulations of the first transit chasers and find out how today’s searches are on the verge of discovering worlds that may harbor life like our own, or creatures very different from us!


Annular Eclipse Party at South Physics

Annular Solar Eclipse party

South Physics Observatory (map)

Sunday, May 20, 2012


Follow Us

Support Us

Make A Difference

Outreach: The Department of Physics & Astronomy at the U

Community Outreach

Scholarships: The Department of Physics & Astronomy at the U

Academic Scholarships

General_Development: The Department of Physics & Astronomy at the U

Other Areas
of Support


Our Newest Program:

Crimson Laureate Society


Click to download full size.

The Department of Physics & Astronomy at the U


Science, it makes us all go


Even Our English Majors Study Physics


The Formula For The Perfect Pass


  • Department of Physics & Astronomy • 201 James Fletcher Bldg. 115 South 1400 East, Salt Lake City, UT 84112-0830
  • PHONE 801-581-6901
  • Fax 801-581-4801
  • ©2018 The University of Utah