Molecular Clouds associated with the Type Ia SNR N103B in the Large Magellanic Cloud

N103B is a Type Ia supernova remnant (SNR) in the Large Magellanic Cloud (LMC). We carried out new $^{12}$CO($J$ = 3-2) and $^{12}$CO($J$ = 1-0) observations using ASTE and ALMA. We have confirmed the existence of a giant molecular cloud (GMC) at $V_\mathrm{LSR}$ $\sim$245 km s$^{-1}$ towards the southeast of the SNR using ASTE $^{12}$CO($J$ = 3-2) data at an angular resolution of $\sim$25$"$ ($\sim$6 pc in the LMC). Using the ALMA $^{12}$CO($J$ = 1-0) data, we have spatially resolved CO clouds along the southeastern edge of the SNR with an angular resolution of $\sim$1.8$"$ ($\sim$0.4 pc in the LMC). The molecular clouds show an expanding gas motion in the position-velocity diagram with an expansion velocity of $\sim5$ km s$^{-1}$. The spatial extent of the expanding shell is roughly similar to that of the SNR. We also find tiny molecular clumps in the directions of optical nebula knots. We present a possible scenario that N103B exploded in the wind-bubble formed by the accretion winds from the progenitor system, and is now interacting with the dense gas wall. This is consistent with a single-degenerate scenario.Comment: 12 pages, 1 table, 8 figures, accepted for publication in The Astrophysical Journal (ApJ

ALMA CO Observations of Supernova Remnant N63A in the Large Magellanic Cloud: Discovery of Dense Molecular Clouds Embedded within Shock-Ionized and Photoionized Nebulae

We carried out new $^{12}$CO($J$ = 1-0, 3-2) observations of a N63A supernova remnant (SNR) from the LMC using ALMA and ASTE. We find three giant molecular clouds toward the northeast, east, and near the center of the SNR. Using the ALMA data, we spatially resolved clumpy molecular clouds embedded within the optical nebulae in both the shock-ionized and photoionized lobes discovered by previous H$\alpha$ and [S II] observations. The total mass of the molecular clouds is $\sim$$800$ $M_{\odot}$ for the shock-ionized region and $\sim$$1700$ $M_{\odot}$ for the photoionized region. Spatially resolved X-ray spectroscopy reveals that the absorbing column densities toward the molecular clouds are $\sim$$1.5$-$6.0\times10^{21}$ cm$^{-2}$, which are $\sim$$1.5$-$15$ times less than the averaged interstellar proton column densities for each region. This means that the X-rays are produced not only behind the molecular clouds, but also in front of them. We conclude that the dense molecular clouds have been completely engulfed by the shock waves, but have still survived erosion owing to their high-density and short interacting time. The X-ray spectrum toward the gas clumps is well explained by an absorbed power-law or high-temperature plasma models in addition to the thermal plasma components, implying that the shock-cloud interaction is efficiently working for both the cases through the shock ionization and magnetic field amplification. If the hadronic gamma-ray is dominant in the GeV band, the total energy of cosmic-ray protons is calculated to be $\sim$$0.3$-$1.4\times10^{49}$ erg with the estimated ISM proton density of $\sim$$190\pm90$ cm$^{-3}$, containing both the shock-ionized gas and neutral atomic hydrogen.Comment: 18 pages, 4 tables, 8 figures, accepted for publication in The Astrophysical Journal (ApJ

Structure based development of novel specific inhibitors for cathepsin L and cathepsin S in vitro and in vivo

AbstractSpecific inhibitors for cathepsin L and cathepsin S have been developed with the help of computer-graphic modeling based on the stereo-structure. The common fragment, N-(L-trans-carbamoyloxyrane-2-carbonyl)-phenylalanine-dimethylamide, is required for specific inhibition of cathepsin L. Seven novel inhibitors of the cathepsin L inhibitor Katunuma (CLIK) specifically inhibited cathepsin L at a concentration of 10−7 M in vitro, while almost no inhibition of cathepsins B, C, S and K was observed. Four of the CLIKs are stable, and showed highly selective inhibition for hepatic cathepsin L in vivo. One of the CLIK inhibitors contains an aldehyde group, and specifically inhibits cathepsin S at 10−7 M in vitro

GMCs and their Type classification in M74: Toward understanding star formation and cloud evolution

We investigated the giant molecular clouds (GMCs) in M74 (NGC 628) obtained by the PHANGS project. We applied the GMC Types according to the activity of star formation: Type I without star formation, Type II with H$\alpha$ luminosity ($L_{\mathrm{H\alpha}}$) smaller than $10^{37.5} \mathrm{erg~s^{-1}}$, and Type III with $L_{\mathrm{H\alpha}}$ greater than $10^{37.5} \mathrm{erg~s^{-1}}$. In total, 432 GMCs were identified, where the individual GMC Types are 65, 203, and 164, for Type I, Type II, and Type III, respectively. The size and mass of the GMCs range from 23 - 237 pc and $10^{4.9}$ - $10^{7.1}$ M$_{\odot}$, showing a trend that mass and radius increase from Type I to II to III. Clusters younger than 4 Myr and HII regions are found to be concentrated within 150 pc of a GMC, indicating a tight association of these young objects with the GMCs. The virial ratio tends to decrease from Type I to III, indicating that Type III GMCs are most relaxed gravitationally among the three. We interpret that GMCs evolve from Type I to III, as previously found in the LMC. The evolutionary timescales of the three Types are estimated to be 2 Myr, 6 Myr, and 4 Myr, respectively, on a steady state assumption, where we assume the timescale of Type III is equal to the age of the associated clusters, indicating a GMC lifetime of 12 Myr or longer. Chevance et al. (2020) investigated GMCs using the same PHANGS dataset of M74, while these authors did not define a GMC, reaching an evolutionary picture with a 20 Myr duration of the non-star forming phase, five times longer than 4 Myr. We compare the present results with those by Chevance et al. (2020) and argue that defining individual GMCs is essential to understanding GMC evolution.Comment: 33 pages, 17 figures, 5 tables