31 research outputs found

    AGN number fraction in galaxy groups and clusters at z < 1.4 from the Subaru Hyper Suprime-Cam survey

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    One of the key questions on active galactic nuclei (AGN) in galaxy clusters is how AGN could affect the formation and evolution of member galaxies and galaxy clusters in the history of the Universe. To address this issue, we investigate the dependence of AGN number fraction (fAGNf_{\rm AGN}) on cluster redshift (zclz_{\rm cl}) and distance from the cluster center (R/R200R/R_{\rm 200}). We focus on more than 27,000 galaxy groups and clusters at 0.1<zcl<1.40.1 < z_{\rm cl} < 1.4 with more than 1 million member galaxies selected from the Subaru Hyper Suprime-Cam. By combining various AGN selection methods based on infrared (IR), radio, and X-ray data, we identify 2,688 AGN. We find that (i) fAGNf_{\rm AGN} increases with zclz_{\rm cl} and (ii) fAGNf_{\rm AGN} decreases with R/R200R/R_{\rm 200}. The main contributors to the rapid increase of fAGNf_{\rm AGN} towards high-zz and cluster center are IR- and radio-selected AGN, respectively. Those results indicate that the emergence of the AGN population depends on the environment and redshift, and galaxy groups and clusters at high-zz play an important role in AGN evolution. We also find that cluster-cluster mergers may not drive AGN activity in at least the cluster center, while we have tentative evidence that cluster-cluster mergers would enhance AGN activity in the outskirts of (particularly massive) galaxy clusters.Comment: 16 pages, 21 figures, and 2 tables, accepted for publication in PAS

    Optical IFU Observations of GOALS Sample with KOOLS-IFU on Seimei Telescope: Initial results of 9 U/LIRGs at z<z < 0.04

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    We present ionized gas properties of 9 local ultra/luminous infrared galaxies (U/LIRGs) at z<z < 0.04 through IFU observations with KOOLS-IFU on Seimei Telescope. The observed targets are drawn from the Great Observatories All-sky LIRG Survey (GOALS), covering a wide range of merger stages. We successfully detect emission lines such as Hβ\beta, [OIII]λ\lambda5007, Hα\alpha, [NII]λλ\lambda\lambda6549,6583, and [SII]λλ\lambda\lambda6717,6731 with a spectral resolution of RR = 1500-2000, which provides (i) spatially-resolved (\sim200-700 pc) moment map of ionized gas and (ii) diagnostics for active galactic nucleus (AGN) within the central \sim3--11 kpc in diameter for our sample. We find that [OIII] outflow that is expected to be driven by AGN tends to be stronger (i) towards the galactic center and (ii) as a sequence of merger stage. In particular, the outflow strength in the late-stage (stage D) mergers is about 1.5 times stronger than that in the early-state (stage B) mergers, which indicates that galaxy mergers could induce AGN-driven outflow and play an important role in the co-evolution of galaxies and supermassive black holes.Comment: 12 pages, 8 figures, and 2 tables, accepted for publication in PAS

    Possible interpretations of the joint observations of UHECR arrival directions using data recorded at the Telescope Array and the Pierre Auger Observatory

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    Effect of Vehicle-to-Grid on generation scheduling: in case of a collection of public holidays on the Japanese calendar

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    With the increase in the amount of photovoltaic power generation (PV) introduced, measures to respond to PV output fluctuations by Vehicle to Grid (V2G), which connects storage batteries of electric vehicles (EV) to the power system, have been studied. Since the usage status of many car changes on weekdays and holidays, the effects of V2G may be evaluated more accurately by considering weekly operation in addition to daily operation. In this study, we will quantitatively evaluate the effects of considering EVs that can be used for the weekly operation of a power supply group, including hydropower plants, in case of a collection of public holidays on the Japanese calendar

    Scenario analysis of balancing capacity market based on unit commitment

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    In 2021, it is scheduled for the creation of the balancing capacity market that can procurement and trade more flexible adjustment power than before, and the detailed design of the system is currently underway. As the number of providers of adjustment power increases as a result of marketization and broadening of the area, not only the reduction of procurement costs but also transparency and fairness of procurement are expected. In this paper, we propose the method to analysis scenarios of the balancing market based on Unit Commitment (UC) that considers the range of adjustment power secured in the regulation capacity market and quantitatively evaluate the effect of the adjustment power on the UC

    Protective Effects of Inulin on Stress-Recurrent Inflammatory Bowel Disease

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    Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the digestive tract and is closely associated with the homeostasis of the gut microbiota. Inulin, as a natural prebiotic, displays anti-inflammatory activity and maintains equilibrium of the intestinal microbiota. In this study, our research aimed to explore the potential of inulin in enhancing intestinal immunity and reducing inflammation in stress-recurrent IBD. In this study, a co-culture intestinal epithelium model and a stress-recurrent IBD mouse model was used to examine the protective effects of inulin. It was observed that inulin digesta significantly reduced pro-inflammatory cytokine expression (CXCL8/IL8 and TNFA) and increased MUC2 expression in intestinal epithelial cells. In vivo, our findings showed that Inulin intake significantly prevented IBD symptoms. This was substantiated by a decrease in serum inflammatory markers (IL-6, CALP) and a downregulation of inflammatory cytokine (Il6) in colon samples. Additionally, inulin intake led to an increase in short-chain fatty acids (SCFAs) in cecal contents and a reduction in the expression of endoplasmic reticulum (ER) stress markers (CHOP, BiP). Our results highlight that inulin can improve stress-recurrent IBD symptoms by modulating microbiota composition, reducing inflammation, and alleviating ER stress. These findings suggested the therapeutic potential of inulin as a dietary intervention for ameliorating stress-recurrent IBD
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