Dark matter (DM) is a mysterious energy component of our Universe which occupies about a quarter of its total energy density. The existence of DM is necessary for realizing our visible world, however, the detailed properties of DM are still unknown. In this talk, I will explain the motivation and...
Supermassive black holes (SMBHs), with masses ranging from 10^6 to 10^10 solar masses (Msun), are known to exist ubiquitously at the centres of galaxies. How such massive objects formed remains a major open question in astrophysics. Recent observations with the James Webb Space Telescope (JWST) have revealed SMBHs with masses...
We present 12CO(J = 1 – 0) mapping observations over ∼1/2 of the optical disk of 12 nearby galaxies from the Fundamental CO 1–0 Transition Survey of nearby galaxies (FACTS), using the ALMA Total Power array. Variations in the 12CO(J = 2 − 1)/12CO(J = 1 − 0) line ratio...
Carbon chain molecules, which consist of a series of carbon atoms, are molecules unique to interstellar space. Of the approximately 320 types of interstellar molecules discovered to date, approximately 40% are classified as carbon chain molecules. The chemistry of carbon chain molecules has been studied in low-mass star-forming regions in...
The ΛCDM paradigm has been remarkably successful in explaining the large-scale structure of the universe, from galaxy clustering to the cosmic microwave background. However, at smaller scales—both galactic and circum-galactic—observations reveal persistent discrepancies that challenge the standard model. These small-scale crises include the core-cusp problem, the missing satellites problem, the...
Over the past two decades, Herschel, ALMA, and JWST have conducted detailed spectroscopic observations of molecular and atomic lines against the dust continuum, offering insights into the interstellar medium of galaxies. To interpret these observations, it is essential to self-consistently model the radiation field, the level populations of atoms and...
Isotopic ratios provide a powerful tool for understanding the origins of materials. Thanks to recent ALMA observations with high sensitivity and high spatial resolution, not only the rings, gaps and spirals in dust continuum emission, but also various molecules, including complex organic molecules as well as many rare isotopologues have...
Supermassive black holes in galaxy cores trigger dynamical outbursts called nuclear transients. The number of such transients has been increasing, leading to discoveries of serendipitous phenomena renewing our understanding. We present spectropolarimetric observations of AT2023clx, among the most nearby nuclear transients classified as a tidal disruption event (TDE). We detected...
Dark matter (DM) is a mysterious energy component of our Universe which occupies about a quarter of its total energy density. The existence of DM is necessary for realizing our visible world, however, the detailed properties of DM are still unknown. In this talk, I will explain the motivation and...
July 2025 15 : 10 dark matter, high-energy astrophysics, and semi-analytic models
Supermassive black holes (SMBHs), with masses ranging from 10^6 to 10^10 solar masses (Msun), are known to exist ubiquitously at the centres of galaxies. How such massive objects formed remains a major open question in astrophysics. Recent observations with the James Webb Space Telescope (JWST) have revealed SMBHs with masses...
June 2025 15 : 10 black holes, early universe, and cosmological simulations
We present 12CO(J = 1 – 0) mapping observations over ∼1/2 of the optical disk of 12 nearby galaxies from the Fundamental CO 1–0 Transition Survey of nearby galaxies (FACTS), using the ALMA Total Power array. Variations in the 12CO(J = 2 − 1)/12CO(J = 1 − 0) line ratio...
May 2025 15 : 30 ALMA, molecular gas, and AGN feedback
Carbon chain molecules, which consist of a series of carbon atoms, are molecules unique to interstellar space. Of the approximately 320 types of interstellar molecules discovered to date, approximately 40% are classified as carbon chain molecules. The chemistry of carbon chain molecules has been studied in low-mass star-forming regions in...
April 2025 15 : 30 Astrochemistry, ALMA, and Nobeyama 45m radio telescope
The ΛCDM paradigm has been remarkably successful in explaining the large-scale structure of the universe, from galaxy clustering to the cosmic microwave background. However, at smaller scales—both galactic and circum-galactic—observations reveal persistent discrepancies that challenge the standard model. These small-scale crises include the core-cusp problem, the missing satellites problem, the...
February 2025 15 : 30 galactic halos, dark matter, and Milky Way
Over the past two decades, Herschel, ALMA, and JWST have conducted detailed spectroscopic observations of molecular and atomic lines against the dust continuum, offering insights into the interstellar medium of galaxies. To interpret these observations, it is essential to self-consistently model the radiation field, the level populations of atoms and...
January 2025 15 : 30 radiative transfer, molecular gas, and AGN Isotopic ratios provide a powerful tool for understanding the origins of materials. Thanks to recent ALMA observations with high sensitivity and high spatial resolution, not only the rings, gaps and spirals in dust continuum emission, but also various molecules, including complex organic molecules as well as many rare isotopologues have...
December 2024 15 : 30 protoplanetary discs, molecular gas, and ALMA Supermassive black holes in galaxy cores trigger dynamical outbursts called nuclear transients. The number of such transients has been increasing, leading to discoveries of serendipitous phenomena renewing our understanding. We present spectropolarimetric observations of AT2023clx, among the most nearby nuclear transients classified as a tidal disruption event (TDE). We detected...
November 2024 15 : 30 transients, AGN, and Subaru
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