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Abstract We present the demography of the dynamics and gas mass fraction of 33 extremely metal-poor galaxies (EMPGs) with metallicities of 0.015–0.195Z⊙and low stellar masses of 104–108M⊙in the local universe. We conduct deep optical integral field spectroscopy (IFS) for the low-mass EMPGs with the medium-high resolution (R= 7500) grism of the 8 m Subaru FOCAS IFU instrument by the EMPRESS 3D survey, and investigate the Hαemission of the EMPGs. Exploiting the resolution high enough for the low-mass galaxies, we derive gas dynamics with the Hαlines by the fitting of three-dimensional disk models. We obtain an average maximum rotation velocity (vrot) of 15 ± 3 km s−1and an average intrinsic velocity dispersion (σ0) of 27 ± 10 km s−1for 15 spatially resolved EMPGs out of 33 EMPGs, and find that all 15 EMPGs havevrot/σ0< 1 suggesting dispersion-dominated systems. There is a clear decreasing trend ofvrot/σ0with the decreasing stellar mass and metallicity. We derive the gas mass fraction (fgas) for all 33 EMPGs, and find no clear dependence on stellar mass and metallicity. Thesevrot/σ0andfgastrends should be compared with young high-zgalaxies observed by the forthcoming JWST IFS programs to understand the physical origins of the EMPGs in the local universe.
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This content will become publicly available on January 15, 2026
Low field electrocaloric effect at isotropic–ferroelectric nematic phase transition
Electric fields withE< 1.2 V μm−1amplitude andf< 100 Hz reduce entropy to induce isotropic–ferroelectric nematic (I–NF) phase transition corresponding to an electrocaloric effect (ECE) with an EC responsivity of ∼ 1.7 × 10−6km V−1.
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- Award ID(s):
- 2210083
- PAR ID:
- 10609436
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Soft Matter
- Volume:
- 21
- Issue:
- 3
- ISSN:
- 1744-683X
- Page Range / eLocation ID:
- 458 to 462
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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