Gravitational Wave Physics at CGWA


Faculty and students from the Center for Gravitational Wave Astronomy (CGWA) have been members of the LIGO Scientific Collaboration (LSC) since 1999. Since then CGWA faculty and students have been engaged in activities related to operations, characterization, and data analyses for the LIGO detectors and the LSC.


Associate Professor Volker Quetschke and his group, including Gregorio Tellez, Andrea Tellez, Darkhan Tuyenbayev, and Oliver Puncken, have been involved in the development of core technologies and instrumentation of the LIGO detector. His group has contributed to the development and improvement of the Advanced LIGO (aLIGO) laser system, the electro-optic modulators, the aLIGO input-optics, and the in-vacuum intensity stabilization. During Advanced LIGO commissioning he worked on the calibration of the gravitational wave response using photon calibrators. Quetschke serves as the Chair of the Lasers and Auxiliary Optics working group of the LSC currently working to develop the next generation detector.

Associate Professor Malik Rakhmanov joined the LIGO project in 1995 when he was a graduate student at Caltech. His PhD advisor was Prof. Barry Barish, director of the LIGO Laboratory, and his academic mentors were Prof. Kip Thorne and Ron Drever, the pioneers of this field who together with Prof. Rai Weiss at MIT founded LIGO. Over the next two decades Rakhmanov participated in all major stages of the development of LIGO. During the design stage, he conducted research to model the interferometer dynamics. During the construction stage he traveled to the detector sites to install the hardware. Finally, during the detection stage he participated in LIGO data analysis developing new algorithms for searches of gravitational waves, working in collaboration with many CGWA colleagues. Rakhmanov’s contributions include modeling of LIGO dynamics, commissioning of the detectors, and development of core algorithms for the data analysis pipelines.

CGWA Affiliate Faculty Rick Savage is a scientist at the LIGO Hanford Observatory and works closely with CGWA faculty and students. CGWA students Sergio Cantu, Andrea Tellez, Forrest Shriver, Pablo Daveloza, Gregorio Tellez, and Darkhan Tuyenbayev worked with Savage, directly contributing to the success of LIGO. One aspect of LIGO that has been most impacted by the contributions of the UTRGV students is calibration, with UTRGV students playing key roles in the development of the LIGO photon calibrators. UTRGV students have also played key roles in installation, commissioning, and operation during Advanced LIGO’s first observing.

Data Analysis

Professor Joe Romano and his students analyze LIGO data looking for evidence of a stochastic background of gravitational waves. A stochastic gravitational-wave background shows up in the data as a random signal; it is basically gravitational-wave "confusion noise" produced by signals that overlap with one another or are too weak to be individually resolved. Such a signal is expected to be produced by gravitational waves that were generated shortly after the Big Bang or by population of inspiralling and merging black holes.

Professor Soma Mukherjee has been a member of the LIGO Scientific Collaboration (LSC) since its inception in 1998 with her two most important contributions in the areas of detector noise analysis and the search for gravitational wave signals from supernovae. Supernovae are rare astronomical events that occur during the last stage of a massive star's life, marked by dramatic and catastrophic destruction explosion. Mukherjee's research group, including Oscar Valdez, Lauro Salazar, and Joseph Mittelstaedt, has developed a new, highly sensitive search method, operating on LIGO science data. With their collaborators at the Embry-Riddle Aeronautical University in Arizona, this is one of the biggest supernova groups in the LSC. Mukherjee with collaborators and students Robert Stone, Shihan Weeratunga, Papia Rizwan, Wenhui Wang, Satzhan Sitmukhambetov, and Hunter Gabbard, have made many 'first-in-the field' contributions to the area of LIGO noise reduction. They have shown how to get rid of sharp noise features called 'violin modes' and how to classify different types of noise signatures that cannot be discerned otherwise, by using highly sophisticated methods.

Professor Soumya Mohanty works on the processing of data from the LIGO detectors using sophisticated signal processing algorithms as a key step in the detection of a gravitational wave signal. Mohanty and Rakhmanov at UTRGV with collaborators Sergey Klimenko and Guenakh Mitlselmakher at the University of Florida, Gainesville showed how data from the two LIGO detectors could be combined to find a gravitational wave signal as well as the position of its astrophysical source on the sky. Mohanty has been involved in pioneering several new algorithms in the area of gravitational wave data analysis. Students and postdocs supervised by Mohanty have similarly made many notable contributions in the area of data analysis. These not only include work related to ground-based detectors such as LIGO, but also future spaced-based detectors and a new approach currently under development for Pulsar Timing Arrays (PTA), in which UTRGV happens to be one of the pioneering institutions.

Research Assistant Professor Joey Shapiro Key is involved in LIGO data analysis searches for gravitational wave signals from unexpected sources. With LSC colleagues she contributes to the search for coincident signals in the two LIGO detectors and measures the structure and characteristics of the signal to determine if it could have come from a gravitational wave source. This work requires a good understanding of the LIGO detectors and their sources of noise as well as sophisticated data analysis techniques to characterize gravitational wave signals with minimal signal assumptions. Her work in parameter estimation for gravitational wave astronomy applies to ground based, space based, and pulsar timing array searches for gravitational waves.

Electromagnetic Followup Observations

Professor and CGWA Director Mario Diaz and his students have participated in activities related to LIGO detector characterization and calibration. He also leads an effort to follow up LIGO discoveries with optical telescopes to try to catch the optical counterpart of these events, scanning the areas in the sky where the gravitational wave source is localized. The study of electromagnetic counterparts of gravitational wave events helps to better understand the nature of the source. The Transient Optical Robotic Observatory of the South (TOROS) telescope is operated by UTRGV faculty and international collaborators and is located in Northwestern Argentina in the mountains of the Atacama dessert.

Education and Outreach

CGWA Director of Education and Outreach Joey Shapiro Key leads the CGWA local, national, and international education and outreach efforts in gravitational wave astronomy. In Brownsville CGWA hosts monthly public telescope viewing at Resaca de la Palma State Park, monthly Science Cafe events at El Hueso de Fraile in downtown Brownsville, Physics Circus performances for schools and community groups, and the annual Rio Grande Science and Arts (RiSA) Festival. CGWA faculty host undergraduate physics students from across the country and local high school teachers for summer research in our NSF funded Research Experience for Undergraduates (REU) and Research Experience for Teachers (RET) programs. Key serves as the Chair of the LIGO Education and Public Outreach (EPO) Committee and leads the Celebrating Einstein art+science collaboration to celebrate Einstein and his ideas through art, music, and dance.