73rd Workshop on Gravitational Waves and Numerical Relativity

Information

Date: Nov. 26 (Tue.) - Nov. 28 (Thu.), 2024
Venue: APCTP HQ, Pohang, Korea
Audience: Researchers and students in astrophysics
Number of participants: 15 Offline
Format: Long and intensive sessions from basic lecture to the latest research with a comfortable atmosphere to ask questions and discuss freely
Organizers
- Yeong-Bok Bae (Chung-Ang University)
- Young-Hwan Hyun (Chung-Ang University)
- Jinho Kim (KASI)
- Kyungmin Kim (KASI)
- Young-Min Kim (KASI)
Sponsor: APCTP, KASI
Contact
- Jinho Kim (jkim at kasi dot re dot kr)
- Young-Min Kim (ymkim715 at gmail dot com)

Program

Time Zone: Korea Standard Time (UTC+09:00)
Nov. 26 (Tue.)
- 13:00 - 13:30 [Student Session] Dongchan Kim (Chung-Ang University)
- 13:30 - 14:00 [Student Session] Minhyo Kim (SKKU)
- 14:00 - 14:30 [Student Session] Myeonghwan Oh (KNU)
- 14:30 - 15:00 [Student Session] Gyeongbin Park (PNU)
- 15:00 - 15:30 Discussion
- 15:30 - 16:00 Coffee Break
- 16:00 - 18:00 [Main Session 1] Hyeonmo Koo (UOS)
- 18:00 - [Dinner]
Nov. 27 (Wed.)
- 10:00 - 12:00 [Main Session 2] Jae-Young Kim (UNIST)
- 12:00 - 13:30 [Lunch]
- 13:30 - 15:30 [Main Session 3] Kyujin Kwak (UNIST)
- 15:30 - 16:00 Coffee Break
- 16:00 - 18:00 [Main Session 4] Jongho Park (KHU)
- 18:00 - [Dinner]
Nov. 28 (Thu.)
- 10:00 - 10:30 [Student Session 2] Jiyoon Sun (Chung-Ang University)
- 10:30 - 12:30 [Main Session 5] Kwang-Il Seon (KASI)
- 12:30 - 13:30 [Lunch]
- 13:30 - 14:30 Discussion

Sessions

Ultralight Dark Matter
- Speaker: Hyeonmo Koo (UOS)
- Time: Nov. 26 (Tue.) 16:00 - 18:00
- Speaking Language:
- Slide Language: English
- Abstract: The cold dark matter (CDM) model used in standard cosmology fails to explain some structures on galactic scales (~kpc). Recently, as an alternative to CDM, there is growing interest in the ultra-light dark matter (ULDM) model, which consists of a pseudoscalar particle motivated by ultra-light axions. This model exhibits different dynamical behavior from CDM, allowing it to explain various phenomena that remain unresolved in our universe. In this presentation, I'm going to discuss the dynamical properties of ULDM, and how it can address specific galactic-scale issues in CDM by offering alternative explanations. Additionally, I also 'very lightly' introduce some research topics of ULDM from a general relativistic perspective.
- Slide File:
Unveiling the Universe with Radio Interferometry: From Black Hole Imaging to Multi-Messenger Astronomy
- Speaker: Jae-Young Kim (UNIST)
- Time: Nov. 27 (Wed.) 10:00 - 12:00
- Speaking Language:
- Slide Language: English
- Abstract: Radio interferometry, particularly with very long baselines, enables observations of the universe at the highest angular resolutions. This talk will review key applications of radio interferometry in studies of compact astrophysical objects, especially supermassive black holes. I will begin with an overview of the basic principles of radio interferometry and high-resolution imaging. We will then examine the Event Horizon Telescope (EHT) imaging of black hole shadows in M87* and, particularly, Sagittarius A*, which allows for precise tests of general relativity and constraints on alternative compact objects. I will also briefly review the basics of black hole accretion and outflow physics, followed by broader applications of radio interferometry to related research areas, including high-resolution imaging of nearby AGNs with the EHT, the search for compact binary supermassive black holes with VLBI, and the role of radio monitoring and follow-ups in studying neutrino-emitting jetted AGNs.
- Slide File:
Nuclear Astrophysics and Its Connection to Gravitational Waves and Numerical Relativity
- Speaker: Kyujin Kwak (UNIST)
- Time: Nov. 27 (Wed.) 13:30 - 15:30
- Speaking Language:
- Slide Language: English
- Abstract: Nuclear astrophysics (NA) has been a longstanding inter-disciplinary research subject bridging nuclear physics and astronomy. For example, NA provides fundamental knowledge for the stellar evolution. In particular, understanding the lifetime of the massive star can hint the formation of the compact binary system which eventually emits gravitational wave (GW) when they merge. This lecture introduces some basics of NA and presents some exemplary topics which show how NA is related to GW and numerical relativity.
- Slide File:
Imaging the Supermassive Black Hole at the Heart of M87 Using Global Millimeter Very Long Baseline Interferometry
- Speaker: Jongho Park (KHU)
- Time: Nov. 27 (Wed.) 16:00 - 18:00
- Speaking Language:
- Slide Language: English
- Abstract: Supermassive black holes (SMBHs) are believed to reside at the centers of most galaxies. The inflow of matter toward SMBHs often results in strong radiation and relativistic jet outflows, which can play crucial roles in the evolution of galaxies and galaxy clusters. The region where this energy is generated is too small to observe directly, and the detailed physical processes of mass accretion and jet outflows have long remained elusive. The recent advent of global Very Long Baseline Interferometry, including the Event Horizon Telescope (EHT) and the Global Millimeter VLBI Array (GMVA) in conjunction with the phased ALMA, has enabled unprecedented ultra-high resolution, allowing us to directly image the horizon-scale view of SMBHs. In this talk, I present recent breakthroughs in supermassive black hole research facilitated by the EHT and GMVA+ALMA, with a primary focus on studies of M87*. I will also discuss how numerical relativity provides a more robust test of black hole accretion and jet formation models based on the observed black hole images of M87.
- Slide File:
Introduction to Radiative Transfer Methods: Applications in Astrophysics
- Speaker: Kwang-Il Seon (KASI)
- Time: Nov. 28 (Thu.) 10:30 - 12:30
- Speaking Language:
- Slide Language: English
- Abstract:
- Slide File:
Characterizing Gravitational Waves from the Hyperbolic Encounter of Two Black Holes
- Speaker: Dongchan Kim (Chung-Ang University)
- Time: Nov. 26 (Tue.) 13:00 - 13:30
- Speaking Language:
- Slide Language: English
- Abstract:
- Slide File:
Characterization on mirror coating of future gravitational wave detector using transmission electron microscope
- Speaker: Minhyo Kim (SKKU)
- Time: Nov. 26 (Tue.) 13:30 - 14:00
- Speaking Language:
- Slide Language: English
- Abstract: The Advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO) detectors have successfully observed gravitational wave (GW) signals since the first detection in 2015. Despite this success, the capability of the detectors to observe GWs from various astronomical sources is limited by coating thermal noise (CTN), especially in the most sensitive frequency range in 100 Hz ~ 300 Hz. To enhance sensitivity, it is essential to replace the high refractive index material in the high reflective mirror coating of the test mass with the lower mechanical loss property material. In order to investigate efficiently, characterization for candidate coating materials is done using Transmission Electron Microscope (TEM) experiment. This talk will present the methods and preliminary results of characterization on the atomic structure of coating material and interfaces of actual multi-layer coating. For more information, the following papers are recommended: https://doi.org/10.1103/PhysRevLett.123.045501, https://doi.org/10.3390/coatings6040061.
- Slide File:
Estimation of very high energy gamma-ray flux produced by the magnetic Penrose process in Sgr A*
- Speaker: Myeonghwan Oh (KNU)
- Time: Nov. 26 (Tue.) 14:00 - 14:30
- Speaking Language:
- Slide Language: English
- Abstract: The Penrose process (PP) presents a theoretical mechanism for extracting energy from rotating black holes (Kerr black holes). However, its astrophysical applicability is limited due to the condition of a relative velocity between decayed fragments. In contrast, the magnetic Penrose process (MPP) overcomes this limitation and achieves maximum efficiency when a neutral particle decays near a rotating black hole. We apply this model to Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Galaxy, which likely hosts an advection-dominated accretion flow (ADAF). ADAF is hot enough for neutron production via thermonuclear reactions and supplies neutrons to polar regions of Sgr A*. Using the Wald solution for the electromagnetic field, we calculate the production rate of accelerated protons by MPP and estimate the gamma-ray flux from proton-proton interactions with the hydrogen gas at the Galactic center. Our model suggests that this gamma-ray emission may account for a meaningful fraction of the observed gamma-ray flux for energies above 10 TeV. Additionally, we estimate that at PeV energies, the accelerated protons transported to Earth contribute roughly 1-4% of the observed cosmic ray flux, assuming stationary diffusion and magnetic field strength of 100 G near Sgr A*.
- Slide File:
Impact of dynamical tides on the measurement accuracy of Neutron star tidal deformability
- Speaker: Gyeongbin Park (PNU)
- Time: Nov. 26 (Tue.) 14:30 - 15:00
- Speaking Language:
- Slide Language: English
- Abstract: Gravitational waves emitted by binary neutron stars (BNS) provide information about the internal structure of neutron stars (NSs), helping to verify dense matter equations of state. We investigate how the measurement accuracy of NS's tidal deformability can be improved by incorporating the higher-order post-Newtonian (pN) tidal corrections. We assume an aligned-spin BNS system and adopt TaylorF2 which is one of the pN waveform models. To compute the measurement errors, we use the Fisher Matrix method which is much faster than performing Monte Carlo simulations. We find that the higher-order corrections beyond 6 post-Newtonian order in adiabatic tides do not contribute largely, while the dynamical tides, describing Love number varying with binary's frequency, significantly reduce the measurement errors.
- Slide File:
Enhancing the search sensitivity for gravitational wave bursts with Gaussian mixture modelling
- Speaker: Jiyoon Sun (Chung-Ang University)
- Time: Nov. 28 (Thu.) 10:00 - 10:30
- Speaking Language:
- Slide Language: English
- Abstract:
- Slide File:

Supports

Accommodation
- If you need accommodation support, select “Full accommodation support is required” in the registration form.
Meals
- Dinner on Nov. 26
- Lunch and Dinner on Nov. 27
- Lunch on Nov. 28

Registration

Link: Google Form
Due
- Accommodation support or reservation is required: Nov. 12 (Tue.)
- No accommodation: Nov. 19 (Tue.)

Organizing Committee for Gravitational Waves and Numerical Relativity in Korea

Other articles

72nd Workshop on Gravitational Waves and Numerical Relativity

Information

71st Workshop on Gravitational Waves and Numerical Relativity

Information

70th Workshop on Gravitational Waves and Numerical Relativity

Information

69th Workshop on Gravitational Waves and Numerical Relativity

Information

68th Workshop on Gravitational Waves and Numerical Relativity

Information

67th Workshop on Gravitational Waves and Numerical Relativity

Information

66th Workshop on Gravitational Waves and Numerical Relativity

Information

65th Workshop on Gravitational Waves and Numerical Relativity

Information

64th Workshop on Gravitational Waves and Numerical Relativity

Information

Other articles

Information

Information

Information

Information

Information

Information

Information

Information

Information

links

social