CO J=2-1 Observations toward the Supernova Remnant G54.1+0.3

We present 12CO J = 2-1 line observations of G54.1+0.3, a composite supernova remnant with a mid-infrared (MIR) loop surrounding the central pulsar wind nebula (PWN). We mapped an area of 12' x 9' around the PWN and its associated MIR loop. We confirm two velocity components that had been proposed to be possibly interacting with the PWN/MIR-loop; the +53 km/s cloud that appears in contact with the eastern boundary of the PWN and the +23 km/s cloud that has CO emission coincident with the MIR loop. We have not found a direct evidence for the interaction in either of these clouds. Instead, we detected an 5'-long arc-like cloud at +15-+23 km/s with a systematic velocity gradient of ~3 km/s/arcmin and broad-line emitting CO gas having widths (FWHM) of <7 km/s in the western interior of the supernova remnant. We discuss their association with the supernova remnant.Comment: 9 pages, 13 figures, accepted for publication in the Journal of the Korean Astronomical Society (JKAS

Infrared Excess and Molecular Gas in Galactic Supershells

We have carried out high-resolution observations along one-dimensional cuts through the three Galactic supershells GS 064-01-97, GS 090-28-17, and GS 174+02-64 in the HI 21 cm and CO J=1-0 lines. By comparing the HI data with IRAS data, we have derived the distributions of the I_100 and tau_100 excesses, which are, respectively, the 100 mum intensity and 100 mum optical depth in excess of what would be expected from HI emission. We have found that both the I_100 and tau_100 excesses have good correlations with the CO integrated intensity W_CO in all three supershells. But the I_100 excess appears to underestimate H_2 column density N(H_2) by factors of 1.5-3.8. This factor is the ratio of atomic to molecular infrared emissivities, and we show that it can be roughly determined from the HI and IRAS data. By comparing the tau_100 excess with W_CO, we derive the conversion factor X = N(H_2)/W_CO = 0.26-0.66 in the three supershells. In GS 090-28-17, which is a very diffuse shell, our result suggests that the region with N(H_2) < 3*10^20 cm^-2 does not have observable CO emission, which appears to be consistent with previous results indicating that diffuse molecular gas is not observable in CO. Our results show that the molecular gas has a 60/100 mum color temperature T_d lower than the atomic gas. The low value of T_d might be due either to the low equilibrium temperature or to the lower abundance of small grains, or a combination of both.Comment: Latex file, 13 pages, 7 postscript figures, uses jkas32.sty Accepted for publication in Jour. of Korean Astron. Societ

End-point resummation in squark decays

We study soft and collinear gluon emission in squark decays to quark--neutralino pair, at next-to-next-to-leading logarithmic (NNLL) accuracy in the end-point region, using Soft Collinear Effective Theory (SCET), and at next-to-leading (NLO) fixed order in the rest of the phase space. As a phenomenological case study we discuss the impact of radiative corrections on the simultaneous measurements of squark and neutralino masses at a linear $e^{+}e^{-}$ collider based on $\sqrt{s} = 3$ TeV Compact Linear Collider (CLIC). Since the majority of mass measurement techniques are based on edges in kinematic distributions, and these change appreciably when there is additional QCD radiation in the final state, the knowledge of higher-order QCD effects is required for precise mass determinations.Comment: 31 pages and 7 figure

Infrared Supernova Remnants and their Infrared to X-ray Flux Ratios

Recent high-resolution infrared space missions have revealed supernova remnants (SNRs) of diverse morphology in infrared (IR) dust emission that is often very different from their X-ray appearance. The observed range of infrared-to-X-ray (IRX) flux ratios of SNRs are also wide. For a sample of 20 Galactic SNRs, we obtain their IR and X-ray properties and investigate the physical causes for such large differences. We find that the observed IRX flux ratios ($R_{IRX.obs}$) are related to the IRX morphology, with SNRs with the largest $R_{IRX,obs}$ showing anticorrelated IRX morphology. By analyzing the relation of $R_{IRX,obs}$ to X-ray and IR parameters, we show that the $R_{IRX,obs}$ of some SNRs agree with theoretical ratios of SNR shocks in which dust grains are heated and destroyed by collisions with plasma particles. For the majority of SNRs, however, $R_{IRX,obs}$ values are either significantly smaller or significantly larger than the theoretical ratios. The latter SNRs have relatively low dust temperatures. We discuss how the natural and/or environmental properties of SNRs could have affected the IRX flux ratios and the IRX morphology of these SNRs. We conclude that the SNRs with largest $R_{IRX,obs}$ are probably located in dense environment and that their IR emission is from dust heated by shock radiation rather than by collisions. Our result suggests that the IRX flux ratio, together with dust temperature, can be used to infer the nature of unresolved SNRs in external galaxies.Comment: 30 pages, 9 figures, Accepted for publication in the Astrophysical Journal on February 11, 201

Measurable Relationship Between Bright Galaxies and Their Faint Companions in WHL J085910.0+294957, a Galaxy Cluster at z = 0.30: Vestiges of Infallen Groups?

The properties of satellite galaxies are closely related to their host galaxies in galaxy groups. In cluster environments, on the other hand, the interaction between close neighbors is known to be limited. Our goal is to examine the relationships between host and satellite galaxies in the harsh environment of a galaxy cluster. To achieve this goal, we study a galaxy cluster WHL J085910.0+294957 at z = 0.30 using deep images obtained with CQUEAN CCD camera mounted on the 2.1-m Otto Struve telescope. After member selection based on the scaling relations of photometric and structural parameters, we investigate the relationship between bright (M_i < -18) galaxies and their faint (-18 < M_i < -15) companions. The weighted mean color of faint companion galaxies shows no significant dependence (< 1 sigma to Bootstrap uncertainties) on cluster-centric distance and local luminosity density as well as the luminosity and concentration of an adjacent bright galaxy. However, the weighted mean color shows marginal dependence (~ 2.2 sigma) on the color of an adjacent bright galaxy, when the sample is limited to bright galaxies with at least 2 faint companions. By using a permutation test, we confirm that the correlation in color between bright galaxies and their faint companions in this cluster is statistically significant with a confidence level of 98.7%. The statistical significance increases if we additionally remove non-members using the SDSS photometric redshift information (~ 2.6 sigma and 99.3%). Our results suggest three possible scenarios: (1) vestiges of infallen groups, (2) dwarf capturing, and (3) tidal tearing of bright galaxies.Comment: 27 pages, 16 figures, accepted for publication in The Astrophysical Journa

A Deep Near-Infrared [Fe II]+[Si I] Emission Line Image of the Supernova Remnant Cassiopeia A

We present a long-exposure (~10 hr) image of the supernova (SN) remnant Cassiopeia A (Cas A) obtained with the UKIRT 3.8-m telescope using a narrow band filter centered at 1.644 um emission. The passband contains [Fe II] 1.644 um and [Si I] 1.645 um lines, and our `deep [Fe II]+[Si I] image' provides an unprecedented panoramic view of Cas A, showing both shocked and unshocked SN ejecta together with shocked circumstellar medium at subarcsec (~0.7 arcsec or 0.012 pc) resolution. The diffuse emission from the unshocked SN ejecta has a form of clumps, filaments, and arcs, and their spatial distribution correlates well with that of the Spitzer [Si II] infrared emission, suggesting that the emission is likely due to [Si I] line not [Fe II] line as in shocked material. The structure of the optically-invisible western area of Cas A is clearly seen for the first time. The area is filled with many Quasi-Stationary Flocculi (QSFs) and fragments of the disrupted ejecta shell. We suggest that the anomalous radio properties in this area could be due to the increased number of such dense clumps. We identified 309 knots in the deep [Fe II]+[Si I] image and classified them into QSFs and fast-moving knots (FMKs). The total H+He mass of QSFs is ~0.23 Msun, implying that the mass fraction of dense clumps in the progenitor's red-supergiant wind is 4--13%. The spatial distribution of QSFs suggests that there had been a highly asymmetric mass loss $10^4$--$10^5$ yr before the SN explosion. The mass of the [Fe II] line-emitting, shocked dense Fe ejecta is ~3x$10^{-5}$ Msun. The comparison with the ionic S-line dominated Hubble Space Telescope WFC3/IR image suggests that the outermost FMKs in the southeastern area are Fe-rich.Comment: 36 pages, 13 figures, ApJ in pres

What determines the sizes of red early-type galaxies?

The sizes of galaxies are known to be closely related with their masses, luminosities, redshifts and morphologies. However, when we fix these quantities and morphology, we still find large dispersions in the galaxy size distribution. We investigate the origin of these dispersions for red early-type galaxies, using two SDSS-based catalogs. We find that the sizes of faint galaxies (log(M_dyn/M_sun) -19.5, where M_r is the r-band absolute magnitude, k-corrected to z = 0.1) are affected more significantly by luminosity, while the sizes of bright galaxies (log(M_dyn/M_sun) > 11.4 or M_r < -21.4) are by dynamical mass. At fixed mass and luminosity, the sizes of low-mass galaxies (log(M_dyn/M_sun) ~ 10.45 and M_r ~ -19.8) are relatively less sensitive to their colors, color gradients and axis ratios. On the other hand, the sizes of intermediate-mass (log(M_dyn/M_sun) ~ 10.85 and M_r ~ -20.4) and high-mass (log(M_dyn/M_sun) ~ 11.25 and M_r ~ -21.0) galaxies significantly depend on those parameters, in the sense that larger red early-type galaxies have bluer colors, more negative color gradients (bluer outskirts) and smaller axis ratios. These results indicate that the sizes of intermediate- and high-mass red early-type galaxies are significantly affected by their recent minor mergers or rotations, whereas the sizes of low-mass red early-type galaxies are affected by some other mechanisms. Major dry mergers also seem to have influenced on the size growth of high-mass red early-type galaxies.Comment: 8 pages, 5 figures, accepted for publication in the Astrophysical Journal Letter

WisenetMD: Motion Detection Using Dynamic Background Region Analysis

Motion detection algorithms that can be applied to surveillance cameras such as CCTV (Closed Circuit Television) have been studied extensively. Motion detection algorithm is mostly based on background subtraction. One main issue in this technique is that false positives of dynamic backgrounds such as wind shaking trees and flowing rivers might occur. In this paper, we proposed a method to search for dynamic background region by analyzing the video and removing false positives by re-checking false positives. The proposed method was evaluated based on CDnet 2012/2014 dataset obtained at "changedetection.net" site. We also compared its processing speed with other algorithms.Comment: 8 page

Unsupervised MR Motion Artifact Deep Learning using Outlier-Rejecting Bootstrap Aggregation

Recently, deep learning approaches for MR motion artifact correction have been extensively studied. Although these approaches have shown high performance and reduced computational complexity compared to classical methods, most of them require supervised training using paired artifact-free and artifact-corrupted images, which may prohibit its use in many important clinical applications. For example, transient severe motion (TSM) due to acute transient dyspnea in Gd-EOB-DTPA-enhanced MR is difficult to control and model for paired data generation. To address this issue, here we propose a novel unsupervised deep learning scheme through outlier-rejecting bootstrap subsampling and aggregation. This is inspired by the observation that motions usually cause sparse k-space outliers in the phase encoding direction, so k-space subsampling along the phase encoding direction can remove some outliers and the aggregation step can further improve the results from the reconstruction network. Our method does not require any paired data because the training step only requires artifact-free images. Furthermore, to address the smoothing from potential bias to the artifact-free images, the network is trained in an unsupervised manner using optimal transport driven cycleGAN. We verify that our method can be applied for artifact correction from simulated motion as well as real motion from TSM successfully, outperforming existing state-of-the-art deep learning methods

A Monte Carlo Study of the Relationship between the Time Structures of Prompt Gammas and in vivo Radiation Dose in Proton Therapy

For the in vivo range verification in proton therapy, it has been tried to measure the spatial distribution of the prompt gammas generated by the proton-induced interactions with the close relationship with the proton dose distribution. However, the high energy of the prompt gammas and background gammas are still problematic in measuring the distribution. In this study, we suggested a new method determining the in vivo range by utilizing the time structure of the prompt gammas formed with the rotation of a range modulation wheel (RMW) in the passive scattering proton therapy. To validate the Monte Carlo code simulating the proton beam nozzle, axial percent depth doses (PDDs) were compared with the measured PDDs with the varying beam range of 4.73-24.01 cm. And the relationship between the proton dose rate and the time structure of the prompt gammas was assessed and compared in the water phantom. The results of the PDD showed accurate agreement within the relative errors of 1.1% in the distal range and 2.9% in the modulation width. Average dose difference in the modulation was assessed as less than 1.3% by comparing with the measurement. The time structure of prompt gammas was well-matched within 0.39 ms with the proton dose rate, and this could enable the accurate prediction of the in vivo range.Comment: 9 pages, a table, and 5 figure