Characterizing Faint Submillimeter Galaxies with Cluster Lensing
Speaker:
徐立研 (Li-Yen Hsu)
Time:
09/09 (Sat.) 3 pm PDT, 4 pm MDT, 5 pm CDT, 6 pm EDT
09/10 (Sun.) 6 am Taiwan
Link:
part 1
part 2
Join the talk on BlueJeans: https://bluejeans.com/6366170552/
Based on
the measurements of the integrated background light from extragalactic
sources, it is known that about half of the starlight is absorbed by dust
and
re-radiated into the far-infrared (FIR). It is therefore important to
study both the unobscured and dust-obscured populations of galaxies across cosmic time for a full picture of the star formation in our universe. At
z > 1, the FIR emission from galaxies is redshifted to the submillimeter. However,
surveys made with single-dish submillimeter telescopes are confusion
limited at low fluxes (< 2 mJy at 850 micron) and can only detect
ultra-luminous galaxies. Consequently,
we have little information about fainter submillimeter galaxies (SMGs),
which are actually the major contributors to the submillimeter background
light and therefore the dominant star-formers in the dusty universe.
Determining how much these faint SMGs overlap the optically selected samples is critical to fully account for the cosmic star formation history. Observations
of massive cluster fields are the best way to study faint galaxies, thanks to
gravitational lensing. To explore the faint submillimeter population,
we have been observing nine galaxy clusters with the SCUBA-2 camera on
the James Clerk Maxwell
Telescope. We also used interferometric observations with the Karl G.
Jansky Very Large Array and the Submillimeter Array to determine the accurate positions
of our detected sources. Our observations have discovered a population of faint SMGs that are undetected in deep radio, optical, and near-infrared images. This suggests that a significant fraction of the population with
infrared luminosities < 10^12 L_sun may be hidden from optical surveys and would not be included in the UV star formation history.
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