16 research outputs found

    CO Multi-line Imaging of Nearby Galaxies (COMING). III. Dynamical effect on molecular gas density and star formation in the barred spiral galaxy NGC 4303

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    We present the results of 12^{12}CO(JJ=1-0) and 13^{13}CO(JJ=1-0) simultaneous mappings toward the nearby barred spiral galaxy NGC 4303 as a part of the CO Multi-line Imaging of Nearby Galaxies (COMING) project. Barred spiral galaxies often show lower star-formation efficiency (SFE) in their bar region compared to the spiral arms. In this paper, we examine the relation between the SFEs and the volume densities of molecular gas n(H2)n(\rm{H}_2) in the eight different regions within the galactic disk with CO data combined with archival far-ultraviolet and 24 μ\mum data. We confirmed that SFE in the bar region is lower by 39% than that in the spiral arms. Moreover, velocity-alignment stacking analysis was performed for the spectra in the individual regions. The integrated intensity ratios of 12^{12}CO to 13^{13}CO (R12/13R_{12/13}) range from 10 to 17 as the results of stacking. Fixing a kinetic temperature of molecular gas, n(H2)n(\rm{H}_2) was derived from R12/13R_{12/13} via non-local thermodynamic equilibrium (non-LTE) analysis. The density n(H2)n(\rm{H}_2) in the bar is lower by 31-37% than that in the arms and there is a rather tight positive correlation between SFEs and n(H2)n(\rm{H}_2), with a correlation coefficient of 0.8\sim 0.8. Furthermore, we found a dependence of n(H2)n(\rm{H}_2) on the velocity dispersion of inter-molecular clouds (ΔV/sini\Delta V/ \sin i). Specifically, n(H2)n(\rm{H}_2) increases as ΔV/sini\Delta V/ \sin i increases when ΔV/sini<100\Delta V/ \sin i < 100 km s1^{-1}. On the other hand, n(H2)n(\rm{H}_2) decreases as ΔV/sini\Delta V/ \sin i increases when ΔV/sini>100\Delta V/ \sin i > 100 km s1^{-1}. These relations indicate that the variations of SFE could be caused by the volume densities of molecular gas, and the volume densities could be governed by the dynamical influence such as cloud-cloud collisions, shear and enhanced inner-cloud turbulence.Comment: 15 pages, 8 figures, accepted for publication in PAS

    KMT-2021-BLG-1150Lb: Microlensing planet detected through a densely covered planetary-caustic signal

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    Recently, there have been reports of various types of degeneracies in the interpretation of planetary signals induced by planetary caustics. In this work, we check whether such degeneracies persist in the case of well-covered signals by analyzing the lensing event KMT-2021-BLG-1150, for which the light curve exhibits a densely and continuously covered short-term anomaly. In order to identify degenerate solutions, we thoroughly investigate the parameter space by conducting dense grid searches for the lensing parameters. We then check the severity of the degeneracy among the identified solutions. We identify a pair of planetary solutions resulting from the well-known inner-outer degeneracy, and find that interpreting the anomaly is not subject to any degeneracy other than the inner-outer degeneracy. The measured parameters of the planet separation (normalized to the Einstein radius) and mass ratio between the lens components are (s,q)in(1.297,1.10×103)(s, q)_{\rm in}\sim (1.297, 1.10\times 10^{-3}) for the inner solution and (s,q)out(1.242,1.15×103)(s, q)_{\rm out}\sim (1.242, 1.15\times 10^{-3}) for the outer solution. According to a Bayesian estimation, the lens is a planetary system consisting of a planet with a mass Mp=0.880.36+0.38 MJM_{\rm p}=0.88^{+0.38}_{-0.36}~M_{\rm J} and its host with a mass Mh=0.730.30+0.32 MM_{\rm h}=0.73^{+0.32}_{-0.30}~M_\odot lying toward the Galactic center at a distance DL=3.81.2+1.3D_{\rm L} =3.8^{+1.3}_{-1.2}~kpc. By conducting analyses using mock data sets prepared to mimic those obtained with data gaps and under various observational cadences, it is found that gaps in data can result in various degenerate solutions, while the observational cadence does not pose a serious degeneracy problem as long as the anomaly feature can be delineated.Comment: 9 pages, 8 figure

    KMT-2022-BLG-0440Lb: A New q<104q < 10^{-4} Microlensing Planet with the Central-Resonant Caustic Degeneracy Broken

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    We present the observations and analysis of a high-magnification microlensing planetary event, KMT-2022-BLG-0440, for which the weak and short-lived planetary signal was covered by both the KMTNet survey and follow-up observations. The binary-lens models with a central caustic provide the best fits, with a planet/host mass ratio, q=0.75q = 0.75--1.00×1041.00 \times 10^{-4} at 1σ1\sigma. The binary-lens models with a resonant caustic and a brown-dwarf mass ratio are both excluded by Δχ2>70\Delta\chi^2 > 70. The binary-source model can fit the anomaly well but is rejected by the ``color argument'' on the second source. From Bayesian analyses, it is estimated that the host star is likely a K or M dwarf located in the Galactic disk, the planet probably has a Neptune-mass, and the projected planet-host separation is 1.90.7+0.61.9^{+0.6}_{-0.7} or 4.61.7+1.44.6^{+1.4}_{-1.7} au, subject to the close/wide degeneracy. This is the third q<104q < 10^{-4} planet from a high-magnification planetary signal (A65A \gtrsim 65). Together with another such planet, KMT-2021-BLG-0171Lb, the ongoing follow-up program for the KMTNet high-magnification events has demonstrated its ability in detecting high-magnification planetary signals for q<104q < 10^{-4} planets, which are challenging for the current microlensing surveys.Comment: MNRAS accepte

    OGLE-2019-BLG-0825: Constraints on the Source System and Effect on Binary-lens Parameters arising from a Five Day Xallarap Effect in a Candidate Planetary Microlensing Event

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    We present an analysis of microlensing event OGLE-2019-BLG-0825. This event was identified as a planetary candidate by preliminary modeling. We find that significant residuals from the best-fit static binary-lens model exist and a xallarap effect can fit the residuals very well and significantly improves χ2\chi^2 values. On the other hand, by including the xallarap effect in our models, we find that binary-lens parameters like mass-ratio, qq, and separation, ss, cannot be constrained well. However, we also find that the parameters for the source system like the orbital period and semi major axis are consistent between all the models we analyzed. We therefore constrain the properties of the source system better than the properties of the lens system. The source system comprises a G-type main-sequence star orbited by a brown dwarf with a period of P5P\sim5 days. This analysis is the first to demonstrate that the xallarap effect does affect binary-lens parameters in planetary events. It would not be common for the presence or absence of the xallarap effect to affect lens parameters in events with long orbital periods of the source system or events with transits to caustics, but in other cases, such as this event, the xallarap effect can affect binary-lens parameters.Comment: 19 pages, 7 figures, 6 tables. Accepted by A

    An Artificial Metallolyase with Pliable 2-His-1-Carboxylate Facial Triad for Stereoselective Michael Addition

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    We repurposed the metal-binding site of a cupin superfamily protein into the 2-his-1-carboxylate facial triad, which is one of the common motifs in natural non-heme enzymes, to construct artificial metalloenzymes that can catalyze new-to-nature reactions. Cu2+-H52A/H58E variant catalyzed the stereoselective Michael addition reaction and was found to bear a flexible metal-binding site in the high-resolution crystal structure. Furthermore, the H52A/H58E/F104W mutant accommodated a water molecule, which was supported by Glu58 and Trp104 residues via hydrogen bonding, presumably leading to high stereoselectivity. Thus, the 2-his-1-carboxylate facial triad was confirmed to be a versatile and promising metal-binding motif for abiological and canonical biological reactions

    DataSheet_1_Circulating plasmablasts and follicular helper T-cell subsets are associated with antibody-positive autoimmune epilepsy.docx

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    Autoimmune epilepsy (AE) is an inflammatory disease of the central nervous system with symptoms that have seizures that are refractory to antiepileptic drugs. Since the diagnosis of AE tends to rely on a limited number of anti-neuronal antibody tests, a more comprehensive analysis of the immune background could achieve better diagnostic accuracy. This study aimed to compare the characteristics of anti-neuronal antibody-positive autoimmune epilepsy (AE/Ab(+)) and antibody-negative suspected autoimmune epilepsy (AE/Ab(-)) groups. A total of 23 patients who met the diagnostic criteria for autoimmune encephalitis with seizures and 11 healthy controls (HC) were enrolled. All patients were comprehensively analyzed for anti-neuronal antibodies; 13 patients were identified in the AE/Ab(+) group and 10 in the AE/Ab(-) group. Differences in clinical characteristics, including laboratory and imaging findings, were evaluated between the groups. In addition, the immunophenotype of peripheral blood mononuclear cells (PBMCs) and CSF mononuclear cells, particularly B cells and circulating Tfh (cTfh) subsets, and multiplex assays of serum and CSF were analyzed using flow cytometry. Patients with AE/Ab(+) did not show any differences in clinical parameters compared to patients with AE/Ab(-). However, the frequency of plasmablasts within PBMCs and CSF in patients with AE/Ab(+) was higher than that in patients with AE/Ab(-) and HC, and the frequency of cTfh17 cells and inducible T-cell co-stimulator (ICOS) expressing cTfh17 cells within cTfh subsets was higher than that in patients with AE/Ab(-). Furthermore, the frequency of ICOShighcTfh17 cells was positively correlated with that of the unswitched memory B cells. We also found that IL-12, IL-23, IL-6, IL-17A, and IFN-γ levels were elevated in the serum and IL-17A and IL-6 levels were elevated in the CSF of patients with AE/Ab(+). Our findings indicate that patients with AE/Ab(+) showed increased differentiation of B cells and cTfh subsets associated with antibody production. The elevated frequency of plasmablasts and ICOS expressing cTfh17 shift in PBMCs may be indicative of the presence of antibodies in patients with AE.</p
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