UMASS Dartmouth Physics Department Colloquia
When: Thursday,
September 3, 2020
6:00 PM
-
8:00 PM
Where: Online
Description: The UMASS Dartmouth Physics Department Colloquia
A weekly seminar series of fully online colloquia featuring speakers from around the globe. This week's colloquia features a series of three lightning talks lasting for the duration of 10-15 minutes each.
Date: Thursday, September 3, 2020
Time: 6:00pm
Zoom Link: https://umassd.zoom.us/j/99969043883
Talk #1
Title: Infrared Transmission and Reflection of Titan Aerosol Analogues Under Vacuum
Speaker:Ashley Lindalia Walker (Chicago State University)
Abstract:
Saturn's moon, Titan, is the only body in the solar system with a thick nitrogen atmosphere that may be similar to that of the Early Earth. Photo-chemistry in Titan's atmosphere, composed mainly of nitrogen and methane, produces incredibly complex organic materials. The purpose of this work is to understand the composition of these organic materials through the use of laboratory atmosphere simulation experiments. The Planetary HAZE Research Chamber (PHAZER) at Johns Hopkins University operated by the Hörst Lab group has been used to simulate a variety of solar system and exoplanet atmospheres including that of Titan. In this chamber, nitrogen and methane gases flow past cold plasma in order to create aerosols called “tholinsâ€; experiments such as these have been used to improve our understanding of the chemistry in Titan's atmosphere for decades. The particles generated in these experiments are deposited as thin films and then analyzed using Fourier transform infrared spectroscopy (FTIR). FTIR provides information regarding the chemical composition and optical properties of the particles and can be compared to remote sensing observations of Titan's atmosphere. We review and compare our spectral data to tholins from previous experiments to provide a better understanding on the habitability of Titan.
Talk #2
Title:Computing Remnant Mass of Binary Black Hole Mergers using EMRI Surrogate Model
Speaker:Estuti Shukla (Indian Institute of Science Education and Research Kolkata)
Abstract:
The EMRI surrogate model (Nur E. M. Rifat, Scott E. Field, Gaurav Khanna, and Vijay Varma Phys. Rev. D 101, 081502(R)) is a reduced-order surrogate model for gravitational waveforms emitted by non-spinning black hole binary systems in the large mass ratio regime. Solving Einstein's equations using numerical relativity for the high mass ratios is extremely challenging and computationally expensive. This model presents a faster and efficient alternative approach to approximate waveforms using the results from the black hole perturbation theory. In this lightning talk, I will present my ongoing research work on using the waveforms generated from this model to compute the remnant (Bondi) mass of the black hole mergers mainly for mass ratios(q) from 10 to 10,000. I shall talk about the sanity checks performed on the results obtained using other models for a smaller mass ratio (q=8) and the importance of arriving at a desirable accuracy. This would include the challenges faced while corroborating the results due to the lack of information from numerical relativity simulations for high mass ratios.
Talk #3
Title: Nodal Discontinuous Galerkin Method to Model Gravitational Waves from Extreme-Mass-Ratio Black Hole Binaries
Speaker:Manas Vishal (IISER Kolkata)
Abstract:
To compute the gravitational wave signal from an Extreme-Mass-Ratio Black Hole Binary (EMRB) system, the primary source for upcoming space-borne LISA, the key is to solve the Teukolsky equation, which is essentially a wave-equation in a black hole spacetime. Thus far, we have developed a numerical solver for the homogeneous part of the Teukolsky equation for a simplified case (scalar waves) that uses the nodal discontinuous Galerkin (dG) method. The next step involves the challenge of modeling a Dirac-delta function, which represents the smaller black hole in the binary system, as a source-term into our solver. We will incorporate the effect of this Dirac-delta through interface conditions between the sub-domains of our multi-domain dG solver.
For additional information please contact Dr. Robert Fisher (rfisher1@umassd.edu) or Dr. Renuka Rajapakse (rrajapakse@umassd.edu)
A weekly seminar series of fully online colloquia featuring speakers from around the globe. This week's colloquia features a series of three lightning talks lasting for the duration of 10-15 minutes each.
Date: Thursday, September 3, 2020
Time: 6:00pm
Zoom Link: https://umassd.zoom.us/j/99969043883
Talk #1
Title: Infrared Transmission and Reflection of Titan Aerosol Analogues Under Vacuum
Speaker:Ashley Lindalia Walker (Chicago State University)
Abstract:
Saturn's moon, Titan, is the only body in the solar system with a thick nitrogen atmosphere that may be similar to that of the Early Earth. Photo-chemistry in Titan's atmosphere, composed mainly of nitrogen and methane, produces incredibly complex organic materials. The purpose of this work is to understand the composition of these organic materials through the use of laboratory atmosphere simulation experiments. The Planetary HAZE Research Chamber (PHAZER) at Johns Hopkins University operated by the Hörst Lab group has been used to simulate a variety of solar system and exoplanet atmospheres including that of Titan. In this chamber, nitrogen and methane gases flow past cold plasma in order to create aerosols called “tholinsâ€; experiments such as these have been used to improve our understanding of the chemistry in Titan's atmosphere for decades. The particles generated in these experiments are deposited as thin films and then analyzed using Fourier transform infrared spectroscopy (FTIR). FTIR provides information regarding the chemical composition and optical properties of the particles and can be compared to remote sensing observations of Titan's atmosphere. We review and compare our spectral data to tholins from previous experiments to provide a better understanding on the habitability of Titan.
Talk #2
Title:Computing Remnant Mass of Binary Black Hole Mergers using EMRI Surrogate Model
Speaker:Estuti Shukla (Indian Institute of Science Education and Research Kolkata)
Abstract:
The EMRI surrogate model (Nur E. M. Rifat, Scott E. Field, Gaurav Khanna, and Vijay Varma Phys. Rev. D 101, 081502(R)) is a reduced-order surrogate model for gravitational waveforms emitted by non-spinning black hole binary systems in the large mass ratio regime. Solving Einstein's equations using numerical relativity for the high mass ratios is extremely challenging and computationally expensive. This model presents a faster and efficient alternative approach to approximate waveforms using the results from the black hole perturbation theory. In this lightning talk, I will present my ongoing research work on using the waveforms generated from this model to compute the remnant (Bondi) mass of the black hole mergers mainly for mass ratios(q) from 10 to 10,000. I shall talk about the sanity checks performed on the results obtained using other models for a smaller mass ratio (q=8) and the importance of arriving at a desirable accuracy. This would include the challenges faced while corroborating the results due to the lack of information from numerical relativity simulations for high mass ratios.
Talk #3
Title: Nodal Discontinuous Galerkin Method to Model Gravitational Waves from Extreme-Mass-Ratio Black Hole Binaries
Speaker:Manas Vishal (IISER Kolkata)
Abstract:
To compute the gravitational wave signal from an Extreme-Mass-Ratio Black Hole Binary (EMRB) system, the primary source for upcoming space-borne LISA, the key is to solve the Teukolsky equation, which is essentially a wave-equation in a black hole spacetime. Thus far, we have developed a numerical solver for the homogeneous part of the Teukolsky equation for a simplified case (scalar waves) that uses the nodal discontinuous Galerkin (dG) method. The next step involves the challenge of modeling a Dirac-delta function, which represents the smaller black hole in the binary system, as a source-term into our solver. We will incorporate the effect of this Dirac-delta through interface conditions between the sub-domains of our multi-domain dG solver.
For additional information please contact Dr. Robert Fisher (rfisher1@umassd.edu) or Dr. Renuka Rajapakse (rrajapakse@umassd.edu)
Contact: > See Description for contact information
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