76 research outputs found
GALAXY CRUISE: Spiral and ring classifications for 700K bright galaxies at z=0.01-0.3
This paper presents a morphology classification catalog of spiral and ring
features of 687,859 magnitude-limited galaxies at =0.01-0.3 (r<20 mag) based
on the Third Public Data Release of the Hyper Suprime-Cam Subaru Strategic
Program. We employ two deep learning classifiers to determine the spiral and
ring structures separately based on GALAXY CRUISE Data Release 1, which is
dedicated to Hyper Suprime-Cam data. The number of spiral and ring galaxies
contain 385,449 and 33,993 sources, respectively, which constitute and
of the sample. A notable result of this study is the construction of a
large sample of ring galaxies utilizing high-quality imaging data delivered by
the Subaru Hyper Suprime-Cam. However, the accurate identification of ring
galaxies remains difficult at a limited seeing resolution. Additionally, we
confirm that most spiral galaxies are located on the star-forming main
sequence, whereas ring galaxies preferentially reside in the green valley at
stellar mass of 1E10.5-11 solar mass. Furthermore, decreasing fractions of
spiral and ring galaxies are observed toward the centers of the galaxy
clusters. The obtained morphology catalog is publicly available on the GALAXY
CRUISE website.Comment: 17 pages, 14 figures, 3 table
Enhanced Star Formation of Less Massive Galaxies in a Proto-Cluster at z=2.5
We investigate a correlation between star-formation rate (SFR) and stellar
mass for Halpha emission line galaxies (HAEs) in one of the richest
proto-clusters ever known at z~2.5, USS 1558-003 proto-cluster. This study is
based on a 9.7-hour narrow-band imaging data with MOIRCS on the Subaru
telescope. We are able to construct a sample, in combination with additional
H-band data taken with WFC3 on Hubble Space Telescope (HST), of 100 HAEs
reaching the dust-corrected SFRs down to 3 Msun/yr and the stellar masses down
to Msun. We find that while the star-forming galaxies with
> Msun are located on the universal SFR-mass main sequence
irrespective of the environment, less massive star-forming galaxies with
< Msun show a significant upward scatter from the main sequence in
this proto-cluster. This suggests that some less massive galaxies are in a
starburst phase, although we do not know yet if this is due to environmental
effects.Comment: 5 pages, 3 figures, 1 table, accepted for publication in the ApJ
Letter
Line-of-sight structure of troughs identified in Subaru Hyper Suprime-Cam Year 3 weak lensing mass maps
We perform the weak lensing mass mapping analysis to identify troughs, which
are defined as local minima in the mass map. Since weak lensing probes
projected matter along the line-of-sight, these troughs can be produced by
single voids or multiple voids projected along the line-of-sight. To scrutinise
the origins of the weak lensing troughs, we systematically investigate the
line-of-sight structure of troughs selected from the latest Subaru Hyper
Suprime-Cam (HSC) Year 3 weak lensing data covering .
From a curved sky mass map constructed with the HSC data, we identify 15
troughs with the signal-to-noise ratio higher than and address their
line-of-sight density structure utilizing redshift distributions of two galaxy
samples, photometric luminous red galaxies observed by HSC and spectroscopic
galaxies detected by Baryon Oscillation Spectroscopic Survey. While most of
weak lensing signals due to the troughs are explained by multiple voids aligned
along the line-of-sight, we find that two of the 15 troughs potentially
originate from single voids at redshift . The single void
interpretation appears to be consistent with our three-dimensional mass mapping
analysis. We argue that single voids can indeed reproduce observed weak lensing
signals at the troughs if these voids are not spherical but are highly
elongated along the line-of-sight direction.Comment: 14 pages, 12 figures, submitted to MNRA
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