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Register a new userMolecular clouds and star formation toward the Galactic plane within 216.25$^{rm o}le$ l $le$218.75$^{rm o}$ and $-$0.75$^{rm o} le$ b $le$1.25$^{rm o}$
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As a part of the Milky Way Imaging Scroll Painting (MWISP) survey, we performed a simultaneous 12CO(1-0), 13CO(1-0), C18O(1-0) mapping toward molecular clouds in a region encompassing 3.75 square degrees. We reveal three molecular clouds, the 15 km/s cloud, the 27 km/s cloud, and the 50 km/s cloud, in the surveyed region. The 50 km/s cloud is resolved with an angular resolution of around 1 for the first time. Investigating their morphology and velocity structures, we find that the 27 km/s cloud is likely affected by feedback from the stellar association Mon OB3 and the 50 km/s cloud is characterised by three large expanding molecular shells. The region is mapped in C18O (1-0) for the first time. We discover seven C18O clumps, which are likely to form massive stars, and 15 dust clumps based on the BGPS archival data. Using infrared color-color diagrams, we find 56 Class I and 107 Class II young stellar object (YSO) candidates. According to the distribution of YSO candidates, an overdensity is found around the HII region S287 and the intersection of two shells, indicative of triggering. The star formation efficiency and rate of the 27~km/s cloud are discussed. Comparing the observed values of the filament S287-main with the models of fragmentation, we suggest that turbulence controls the large scale of fragmentation in the filament while gravitational fragmentation plays an important role in the formation of YSOs on the small scale. We find that star-forming gas tends to have higher excitation temperature, higher 13CO opacity, and higher column density than non-star-forming gas, which is consistent with the point that star formation happens in denser gas and star-forming gas is heated by YSOs. Using the 1.1 mm dust emission to trace dense gas, we obtain a dense gas fraction of 2.7%-10.4% for the 27 km/s cloud.
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We compute by hand all quadratic homogeneous polynomial maps $H$ and all Keller maps of the form $x + H$, for which ${rm rk} J H = 3$, over a field of arbitrary characteristic. Furthermore, we use computer support to compute Keller maps of the form $x + H$ with ${rm rk} J H = 4$, namely: $bullet$ all such maps in dimension $5$ over fields with $frac12$; $bullet$ all such maps in dimension $6$ over fields without $frac12$. We use these results to prove the following over fields of arbitrary characteristic: for Keller maps $x + H$ for which ${rm rk} J H le 4$, the rows of $J H$ are dependent over the base field.
The kinetics and vibrational relaxation of the ${rm N}(^4S) +{rm O}_2(X^3Sigma^-_g) leftrightarrow {rm O}(^3P) + {rm NO}(X^2Pi)$ reaction is investigated over a wide temperature range based on quasiclassical trajectory simulations on 3-dimensional potential energy surfaces (PESs) for the lowest three electronic states. Reference energies at the multi reference configuration interaction level are represented as a reproducing kernel and the topology of the PESs is rationalized by analyzing the CASSCF wavefunction of the relevant states. The forward rate matches one measurement at 1575 K and is somewhat lower than the high-temperature measurement at 2880 K whereas for the reverse rate the computations are in good agreement for temperatures between 3000 and 4100 K. The temperature-dependent equilibrium rates are consistent with results from JANAF and CEA results. Vibrational relaxation rates for O + NO($ u=1$) $rightarrow$ O + NO($ u=0$) are consistent with a wide range of experiments. This process is dominated by the dynamics on the $^2$A$$ and $^4$A$$ surfaces which both contribute similarly up to temperatures $T sim 3000$ K, and it is found that vibrationally relaxing and non-relaxing trajectories probe different parts of the potential energy surface. The total cross section depending on the final vibrational state monotonically decreases which is consistent with early experiments and previous simulations but at variance with other recent experiments which reported an oscillatory cross section.
The structure of anticyclic operad on the Dendriform operad defines in particular a matrix of finite order acting on the vector space spanned by planar binary trees. We compute its characteristic polynomial and propose a (compatible) conjecture for the characteristic polynomial of the Coxeter transformation for the Tamari lattice, which is mostly a square root of this matrix.
The $^{15}{rm N}(p,gamma)^{16}{rm O}$ reaction provides a path from the CN cycle to the CNO bi-cycle and CNO tri-cycle. The measured astrophysical factor for this reaction is dominated by resonant capture through two strong $J^{pi}=1^{-}$ resonances at $E_{R}= 312$ and 962 keV and direct capture to the ground state. Recently, a new measurement of the astrophysical factor for the $^{15}{rm N}(p,gamma)^{16}{rm O}$ reaction has been published [P. J. LeBlanc {it et al.}, Phys. Rev. {bf C 82}, 055804 (2010)]. The analysis has been done using the $R$-matrix approach with unconstrained variation of all parameters including the asymptotic normalization coefficient (ANC). The best fit has been obtained for the square of the ANC $C^{2}= 539.2$ fm${}^{-1}$, which exceeds the previously measured value by a factor of $approx 3$. Here we present a new $R$-matrix analysis of the Notre Dame-LUNA data with the fixed within the experimental uncertainties square of the ANC $C^{2}=200.34$ fm${}^{-1}$. Rather than varying the ANC we add the contribution from a background resonance that effectively takes into account contributions from higher levels. Altogether we present 8 fits, five unconstrained and three constrained. In all the fits the ANC is fixed at the previously determined experimental value $C^{2}=200.34$ fm${}^{-1}$. For the unconstrained fit with the boundary condition $B_{c}=S_{c}(E_{2})$, where $E_{2}$ is the energy of the second level, we get $S(0)=39.0 pm 1.1 $ keVb and normalized ${tilde chi}^{2}=1.84$, i.e. the result which is similar to [P. J. LeBlanc {it et al.}, Phys. Rev. {bf C 82}, 055804 (2010)]. From all our fits we get the range $33.1 leq S(0) leq 40.1$ keVb which overlaps with the result of [P. J. LeBlanc {it et al.}, Phys. Rev. {bf C 82}, 055804 (2010)]. We address also physical interpretation of the fitting parameters.
We present a new picture that the $alpha$-linear-chain structure for ${^{12}{rm C}}$ and ${^{16}{rm O}}$ has one-dimensional $alpha$ condensate character. The wave functions of linear-chain states which are described by superposing a large number of Brink wave functions have extremely large overlaps of nearly $100%$ with single Tohsaki-Horiuchi-Schuck-Ropke (THSR) wave functions, which were proposed to describe the $alpha$ condensed gas-like states. Although this new picture is different from the conventional idea of the spatial localization of $alpha$ clusters, the density distributions are shown to have localized $alpha$-clusters which is due to the inter-$alpha$ Pauli repulsion.
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