695 research outputs found
The investigation into the Ice shelf-Ocean Interaction of East Antarctica with special focusing on the Ocean Circulation
The Tenth Symposium on Polar Science/Special session: [S] Future plan of Antarctic research: Towards phase X of the Japanese Antarctic Research Project (2022-2028) and beyond, Tue. 3 Dec. / 2F Auditorium, National Institute of Polar Researc
A Search for Molecular Gas toward a BzK-selected Star-forming Galaxy at z = 2.044
We present a search for CO(3-2) emission in SDF-26821, a BzK-selected
star-forming galaxy (sBzK) at z = 2.044, using the 45-m telescope of the
Nobeyama Radio Observatory and the Nobeyama Millimeter Array. We do not detect
significant emission and derive 2 \sigma limits: the CO luminosity of L'CO <
3.1 x 10^10 K km s^{-1} pc^{-2}, the ratio of far-infrared luminosity to CO
luminosity of L_FIR/L'CO > 57 Lsun (K km s^{-1} pc^{-2})^{-1}, and the
molecular gas mass of M_H2 < 2.5 x 10^10 Msun, assuming a velocity width of 200
km s^{-1} and a CO-to-H2 conversion factor of alpha_CO=0.8 Msun (K km s^{-1}
pc^{-2})^{-1}. The ratio of L_FIR/L'CO, a measure of star formation efficiency
(SFE), is comparable to or higher than the two z ~ 1.5 sBzKs detected in
CO(2-1) previously, suggesting that sBzKs can have a wide range of SFEs.
Comparisons of far-infrared luminosity, gas mass, and stellar mass among the
sBzKs suggest that SDF-26821 is at an earlier stage of forming stars with a
similar SFE and/or more efficiently forming stars than the two z ~ 1.5 sBzKs.
The higher SFEs and specific star formation rates of the sBzKs compared to
local spirals are indicative of the difference in star formation modes between
these systems, suggesting that sBzKs are not just scaled-up versions of local
spirals.Comment: 4 pages, 4 figures, Accepted for publication in PAS
Variable Stars in the Magellanic Clouds: Results from OGLE and SIRIUS
We have performed a cross-identification between OGLE-II data and
single-epoch SIRIUS JHK survey data in the LMC and SMC. After eliminating
obvious spurious variables, we determined the pulsation periods for 9,681 and
2,927 variables in the LMC and SMC, respectively. Based on these homogeneous
data, we studied the pulsation properties and metallicity effects on period-K
magnitude (PK) relations by comparing the variable stars in the LMC and SMC.
The sample analyzed here is much larger, and we found the following new
features: (1) variable red giants in the SMC form parallel sequences on the PK
plane, just like those found by Wood (2000) in the LMC; (2) both of the
sequences A and B of Wood (2000) have discontinuities, and they occur at the
K-band luminosity of the TRGB; (3) the sequence B of Wood (2000) separates into
three independent sequences B+- and C'; (4) comparison between the theoretical
pulsation models (Wood et al. 1996) and observational data suggests that the
variable red giants on sequences C and newly discovered C' are pulsating in the
fundamental and first overtone mode, respectively; (5) the theory can not
explain the pulsation mode of sequences A+- and B+-, and they are unlikely to
be the sequences for the first and second overtone pulsators, as was previously
suggested; (6) the zero points of PK relations of Cepheids in the metal
deficient SMC are fainter than those of LMC ones by ~0.1 mag but those of SMC
Miras are brighter than those of LMC ones by ~0.13 mag, which are probably due
to metallicity effects.Comment: 9 pages, 10 figures, accepted for publication in MNRAS. High
resolution version is available at:
http://www.ioa.s.u-tokyo.ac.jp/~yita/scr/astro/papers/RefereedPaper/yitaMD250
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