#author("2023-03-28T08:14:35+00:00","default:wwwadm","wwwadm")
#author("2023-04-18T04:43:50+00:00","default:wwwadm","wwwadm")
[[IoA_Seminar]]

#contents

　
* 講演リスト [#g8648f7a]

** No. 399: 28 th Mar. 2023 (Tue) 15:00 - 16:00 [#p0e922cb]
** No. 400: 6 th Apr. 2023 (Thu) 15:30-16:30 [#n2f92204]

*** Speaker: Seiji Fujimoto (UT Austin) [#oc0a379b]
*** Speaker: Doug Johnstone (Principal Research Officer, Herzberg Astronomy and Astrophysics Research Centre and President’s Science Advisor, National Research Council Canada) [#qba3fbc6]

*** Title: Exploring visible and obscured sides of the early Universe – Today and Beyond [#ge6f72fe]
*** Title: What the Variability of Embedded Protostars Tells Us about Accretion: Past, Present, and Future [#l6afbc71]

Language: English

Abstract: Understanding galaxy formation and evolution requires comprehensive
observations of radiation from distant galaxies composed of stars, gas, and
dust. In this talk, I will overview my recent and ongoing studies on
distant Universe in scales of the cosmic structure, circumgalactic and
interstellar media, and central black holes, with the optical/NIR and
submm/mm facilities such as Hubble, ALMA, and JWST. First, I will present
the results from the 100-hrs large program of the ALMA Lensing Cluster
Survey and its implication for the origin of the CIB and the hidden side of
the cosmic star-formation rate density. Next, I will talk about the Baryon
cycle in and outside of early galaxies revealed by deep ALMA and JWST
observations, and young quasars at z~5-9 reported one after another since
the JWST began its operation, along with the discovery of a rapidly growing
young quasar in a dust-enshrouded starburst at z=7.2. Finally, I will
introduce ongoing JWST and ALMA programs that I have been leading as PI and
a JWST large Lensing Cluster Survey in planning.
Abstract: The James Clerk Maxwell Telescope (JCMT) has been monitoring eight nearby
low-mass star-forming regions in the Gould Belt at submillimetre
wavelengths for over six years to search for and quantify the time
dependent brightness variability of the resident deeply embedded
protostars. Secular variability is common among these protostars; greater
than 25% of the sample show measurable long-term brightness changes and 10%
show burst behaviour lasting months to years. We interpret this secular
variability as reflecting changes in the mass accretion rate from the disk
to the protostar, as predicted by theoretical models of (proto)stellar
assembly.  For a subset of our sample we have contemporaneous mid-IR
light-curves which allow additional constraints on the conditions
responsible for the brightness variations, confirming that the
submillimetre variability is driven by changes in the dust temperature
profile of the envelope. Furthermore, we have combined, for one source,
single dish and interferometric sub-mm monitoring, which has allowed us to
unambiguously recover a time lag in the variability at larger angular
scales and use the results to confirm the envelope structure surrounding
the embedded protostar. More recently, we have added somewhat more distant
intermediate mass regions to our JCMT monitoring and collaborated with the
Maser Monitoring Organization (M2O) in follow-up of more massive protostar
candidate variables.
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