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Colloquia are not recorded.
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Ayumi TakahashiKanagawa University
Date: Friday 11 September 2026Time: 3pm - 4pm (ADT)Venue: AT 101
Most galaxies have supermassive black holes at their center. These black holes might have co-evolved with their host galaxies, interacting with each other across cosmic history. We can identify supermassive black holes as active galactic nuclei (AGN) and quasars, which are among the most consistently bright objects in the universe. Beyond redshift 6, quasars with black holes exceeding 1 billion solar masses have been found; these observational findings pose a challenge to our understanding of how black holes grew from their seeds within such a short timescale. We would like to keep track of this investigation. However, such massive black holes have already matured and lost the memory of their early growth. Meanwhile, theoretical models imply that black holes can only grow by a factor of a few under sub-Eddington accretion, and that super- or high-Eddington accretion is a key parameter for black hole growth. Low black hole mass, high-Eddington ratio sources would represent the missing piece in the black hole growth pathway. Narrow-line Seyfert 1 galaxies are known to be low-mass, high-Eddington accretion objects in the local universe, and they, along with their bright analogs (narrow-line Type-1 quasars; NLQ1s), may represent such a population at high redshift as well.
We therefore launched the NLS1/NLQ1 search project using the Subaru Prime Focus Spectrograph (PFS). PFS is a massively multiplexed fiber spectrograph installed at the prime focus of the 8.2-meter Subaru Telescope. This instrument covers optical and near-infrared wavelengths with ~2400 science fibers distributed over a 1.3 deg2 field of view. Since this class has traditionally been identified using the Hβ and [OIII] lines, statistical studies of NLS1s at z>2 remain largely unexplored due to the observational limitations of ground-based telescopes. To extend a comprehensive understanding of this population to the more distant universe, we searched for broad-line AGNs (quasars) whose rest-frame UV spectral shapes resemble those of local NLS1 galaxies, utilizing the Lyα line profile. As a result, four NLQ1s at 2.5 - 6.1 were identified, and this z~6 object is one of the most distant NLS1 candidates. This is the first science result from the PFS-SSP (Subaru Strategic Program) project. I will introduce the current status of Subaru/PFS and this NLS1/NLQ1 search project.
Karina CaputiGroningen
Date: Friday 18 September 2026Time: 3pm - 4pm (ADT)Venue: AT 101
SMHr-IL: A Tool for High-Resolution Integrated Light Spectroscopy
Charli SakariSan Francisco State University
Date: Friday 25 September 2026Time: 3pm - 4pm (ADT)Venue: AT 101
Evidence for the First Globular Cluster Stellar Stream beyond the Milky Way
Julie Kiel HolmCopenhagen
Date: Friday 2 October 2026Time: 3pm - 4pm (ADT)Venue: AT 101
Caffe AP
Date: Friday 9 October 2026Time: 3pm - 4pm (ADT)Venue: AT 101
Lily WhitlerCambridge
Date: Friday 16 October 2026Time: 3pm - 4pm (ADT)Venue: AT 101
Rogier WindhorstArizona State University
Inside the nucleus, inside the stars : Experimental constrains on X-ray Bursts and proton-rich nucleosynthesis with MUSIC
Eilens Lopez-SaavedraArgonne National Laboratory
Date: Friday 30 October 2026Time: 3pm - 4pm (ADT)Venue: AT 101
Understanding dense stellar environments with gravitational wave catalogs
Aditya VijaykumarCanadian Institute for Theoretical AstrophysicsChicago
Date: Friday 6 November 2026Time: 3pm - 4pm (AST)Venue: AT 101
Fall Break - No TalkFriday 13 November
Jason HesselsMcGill University
Date: Friday 20 November 2026Time: 3pm - 4pm (AST)Venue: AT 101
TBA
Date: Friday 27 November 2026Time: 3pm - 4pm (AST)Venue: AT 101
Ruben SandapanAcadia University
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