15 research outputs found
EMPRESS. IX. Extremely Metal-Poor Galaxies are Very Gas-Rich Dispersion-Dominated Systems: Will JWST Witness Gaseous Turbulent High-z Primordial Galaxies?
We present kinematics of 6 local extremely metal-poor galaxies (EMPGs) with
low metallicities () and low stellar masses
(). Taking deep medium-high resolution
() integral-field spectra with 8.2-m Subaru, we resolve the small
inner velocity gradients and dispersions of the EMPGs with H emission.
Carefully masking out sub-structures originated by inflow and/or outflow, we
fit 3-dimensional disk models to the observed H flux, velocity, and
velocity-dispersion maps. All the EMPGs show rotational velocities () of 5--23 km s smaller than the velocity dispersions
() of 17--31 km s, indicating dispersion-dominated () systems affected by inflow and/or outflow. Except
for two EMPGs with large uncertainties, we find that the EMPGs have very large
gas-mass fractions of . Comparing our results with
other H kinematics studies, we find that
decreases and increases with decreasing metallicity, decreasing
stellar mass, and increasing specific star-formation rate. We also find that
simulated high- () forming galaxies have gas fractions and dynamics
similar to the observed EMPGs. Our EMPG observations and the simulations
suggest that primordial galaxies are gas-rich dispersion-dominated systems,
which would be identified by the forthcoming James Webb Space Telescope (JWST)
observations at .Comment: Submitted to ApJ; After revisio
EMPRESS. XII. Statistics on the Dynamics and Gas Mass Fraction of Extremely-Metal Poor Galaxies
We present demography of the dynamics and gas-mass fraction of 33 extremely
metal-poor galaxies (EMPGs) with metallicities of and low
stellar masses of in the local universe. We conduct deep
optical integral-field spectroscopy (IFS) for the low-mass EMPGs with the
medium high resolution () grism of the 8m-Subaru FOCAS IFU instrument
by the EMPRESS 3D survey, and investigate H emission of the EMPGs.
Exploiting the resolution high enough for the low-mass galaxies, we derive gas
dynamics with the H lines by the fitting of 3-dimensional disk models.
We obtain an average maximum rotation velocity () of
and an average intrinsic velocity dispersion
() of for 15 spatially resolved EMPGs
out of the 33 EMPGs, and find that all of the 15 EMPGs have
suggesting dispersion dominated systems. There is a
clear decreasing trend of with the decreasing stellar
mass and metallicity. We derive the gas mass fraction () for
all of the 33 EMPGs, and find no clear dependence on stellar mass and
metallicity. These and trends should
be compared with young high- galaxies observed by the forthcoming JWST IFS
programs to understand the physical origins of the EMPGs in the local universe.Comment: 18 pages, 9 figures, accepted for publication in Ap
Development of a Japanese Version of the Formula for Calculating Periodontal Inflamed Surface Area: A Simulation Study
The periodontal inflamed surface area (PISA) is a useful indicator of periodontal status. However, its formula was based on a meta-analysis involving five countries, and racial differences in tooth root morphology could have affected the calculations. This study aimed to develop a Japanese version of the PISA and compare it with the original version. The formulas reported by a previous Japanese study calculating the amount of remaining periodontal ligament from clinical attachment measurements were used to calculate the PISA. A simulation was performed to compare the Japanese version with the original version by inputting probing pocket depth (PPD) from 1 to10 mm and by using clinical data. The PISA values in the Japanese version were larger and smaller than those in the original version for PPDs of 1–5 mm and 6–10 mm, respectively. The PISA values for the clinical data from the Japanese version were significantly higher than those from the original version. Both versions of the PISA values correlated equally well with body mass index. The Japanese version of the PISA can be used to assess the amount of inflamed periodontal tissue resulting from periodontitis in Japanese populations, taking into account racial heterogeneity in root morphologies
Uremic pleuritis diagnosed by thoracoscopic pleural biopsy in three patients undergoing maintenance hemodialysis who presented with hemorrhagic pleural effusion
EMPRESS. XIV. Strong High-ionization Lines of Young Galaxies at z = 0–8: Ionizing Spectra Consistent with the Intermediate-mass Black Holes with M BH ∼ 103–106 M ⊙
We present ionizing spectra estimated at 13.6–100 eV for 10 dwarf galaxies with strong high-ionization lines of He ii λ 4686 and [Ne v ] λ 3426 ([Ne iv ] λ 2424) at z = 0 ( z = 8) that are identified in our Keck/LRIS spectroscopy and the literature (the JWST Early Release Observations program). With the flux ratios of these high-ionization lines and >10 low-ionization lines of hydrogen, helium, oxygen, neon, and sulfur, we determine ionizing spectra consisting of stellar and nonthermal power-law radiation by photoionization modeling with free parameters of nebular properties, including metallicity and ionization parameter, canceling out abundance ratio differences. We find that all of the observed flux ratios are well reproduced by the photoionization models with the power-law index α _EUV of α _EUV ∼ (–1) − 0 and the luminosity L _EUV of L _EUV ∼ 10 ^40 –10 ^42 erg s ^−1 at ∼55–100 eV for six galaxies, while four galaxies include large systematics in α _EUV caused by stellar radiation contamination. We then compare α _EUV and L _EUV of these six galaxies with those predicted by the black hole (BH) accretion disk models and find that α _EUV and L _EUV are similar to those of the intermediate-mass BHs (IMBHs) in BH accretion disk models, albeit with possibilities of the other scenarios. Confirming these results with a known IMBH having a mass M _BH of M _BH = 10 ^5.75 M _⊙ , we find that four local galaxies and one z = 7.665 galaxy have ionizing spectra consistent with those of IMBHs with M _BH ∼ 10 ^3 –10 ^5 M _⊙