Deblurring galaxy images with Tikhonov regularization on magnitude domain

We propose a regularization-based deblurring method that works efficiently for galaxy images. The spatial resolution of a ground-based telescope is generally limited by seeing conditions and much worse than space-based telescopes. This circumstance has generated considerable research interest in restoration of spatial resolution. Since image deblurring is a typical inverse problem and often ill-posed, solutions tend to be unstable. To obtain a stable solution, much research has adopted regularization-based methods for image deblurring, but the regularization term is not necessarily appropriate for galaxy images. Although galaxies have an exponential or Sersic profile, the conventional regularization assumes the image profiles to behave linear in space. The significant deviation between the assumption and real situation leads to blurring the images and smoothing out the detailed structures. Clearly, regularization on logarithmic, i.e. magnitude domain, should provide a more appropriate assumption, which we explore in this study. We formulate a problem of deblurring galaxy images by an objective function with a Tikhonov regularization term on magnitude domain. We introduce an iterative algorithm minimizing the objective function with a primal-dual splitting method. We investigate the feasibility of the proposed method using simulation and observation images. In the simulation, we blur galaxy images with a realistic point spread function and add both Gaussian and Poisson noises. For the evaluation with the observed images, we use galaxy images taken by the Subaru HSC-SSP. Both of these evaluations show that our method successfully recovers the spatial resolution of the images and significantly outperforms the conventional methods. The code is publicly available from the Github ( https://github.com/kzmurata-astro/PSFdeconv_amag ).Comment: 14 pages, 9 figures, accepted for publication in PASJ. The code is available at https://github.com/kzmurata-astro/PSFdeconv_ama

Scaling Behavior of Angular Dependent Resistivity in CeCoIn5_5: Possible Evidence for d-Wave Density Waves

In-plane angular dependent resistivity ADR was measured in the non-Fermi liquid regime of CeCoIn$_5$ single crystals at temperatures $T \le 20$ K and in magnetic fields $H$ up to 14 T. Two scaling behaviors were identified in low field region where resistivity shows T-linear dependence, separated by a critical angle $\theta_{c}$ which is determined by the anisotropy of CeCoIn$_5$; i.e., ADR depends only on the perpendicular (parallel) field component below (above) $\theta_c$. These scaling behaviors and other salient features of ADR are consistent with d-wave density waves

Unconventional spin density wave in Bechgaard salt (TMTSF)2NO3

Among many Bechgaard salts, TMTSF2NO3 exhibits very anomalous low temperature properties. Unlike conventional spin density wave (SDW), TMTSF2NO3 undergoes the SDW transition at \T_SDW\approx 9.5 K and the low temperature quasiparticle excitations are gapless. Also, it is known that TMTSF2NO3 does not exhibit superconductivity even under pressure, while FISDW is found in TMTSF2NO3 only for P=8.5 kbar and B>20 T. Here we shall show that both the angle dependent magnetoresistance data and the nonlinear Hall resistance of TMTSF2NO3 at ambient pressure are interpreted satisfactory in terms of unconventional spin density wave (USDW). Based on these facts, we propose a new phase diagram for Bechgaards salts.Comment: 4 pages, 4 figs, RevTe

Linear Sigma Models of H and KK Monopoles

We propose a gauged linear sigma model of k H-monopoles. We also consider the T-dual of this model describing KK-monopoles and clarify the meaning of "winding coordinate" studied recently in hep-th/0507204.Comment: 13 pages, lanlmac; V3:added argument on the nature of disk instanto

The Coffee Market in Japan

This publication presents information on Japan in the world coffee market. It includes distribution channels in Japan and consumer profiles and perceptions

Gapped optical excitations from gapless phases: imperfect nesting in unconventional density waves

We consider the effect of imperfect nesting in quasi-one-dimensional unconventional density waves in the case, when the imperfect nesting and the gap depends on the same wavevector component. The phase diagram is very similar to that in a conventional density wave. The density of states is highly asymmetric with respect to the Fermi energy. The optical conductivity at T=0 remains unchanged for small deviations from perfect nesting. For higher imperfect nesting parameter, an optical gap opens, and considerable amount of spectral weight is transferred to higher frequencies. This makes the optical response of our system very similar to that of a conventional density wave. Qualitatively similar results are expected in d-density waves.Comment: 8 pages, 7 figure

Particle trapping in merging flow junctions by fluid-solute-colloid-boundary interactions

Merging of different streams in channel junctions represents a common mixing process that occurs in systems ranging from soda fountains and bathtub faucets to chemical plants and microfluidic devices. Here, we report a spontaneous trapping of colloidal particles in a merging flow junction when the merging streams have a salinity contrast. We show that the particle trapping is a consequence of nonequilibrium interactions between the particles, solutes, channel, and the freestream flow. A delicate balance of transport processes results in a stable near-wall vortex that traps the particles. We use three-dimensional particle visualization and numerical simulations to provide a rigorous understanding of the observed phenomenon. Such a trapping mechanism is unique from the well-known inertial trapping enabled by vortex breakdown [Proc. Natl. Acad. Sci. USA 111, 4770 (2014)], or the solute-mediated trapping enabled by diffusiophoresis [Phys..Rev. X 7, 041038 (2017)], as the current trapping is facilitated by both the solute and the inertial effects, suggesting a new mechanism for particle trapping in flow networks

Particle Energization in an Expanding Magnetized Relativistic Plasma

Using a 2-1/2-dimensional particle-in-cell (PIC) code to simulate the relativistic expansion of a magnetized collisionless plasma into a vacuum, we report a new mechanism in which the magnetic energy is efficiently converted into the directed kinetic energy of a small fraction of surface particles. We study this mechanism for both electron-positron and electron-ion (mi/me=100, me is the electron rest mass) plasmas. For the electron-positron case the pairs can be accelerated to ultra-relativistic energies. For electron-ion plasmas most of the energy gain goes to the ions.Comment: 7 pages text plus 5 figures, accepted for publication by Physical Review Letter

Global AdS Picture of 1/2 BPS Wilson Loops

We study the holographic dual string configuration of 1/2 BPS circular Wilson loops in N=4 super Yang-Mills theory by using the global coordinate of AdS. The dual string worldsheet is given by the Poincare disk AdS_2 sitting at a constant global time slice of AdS_5. We also analyze the correlator of two concentric circular Wilson loops from the global AdS perspective and study the phase transition associated with the instability of annulus worldsheet connecting the two Wilson loops.Comment: 14 pages, 3 figures, v2: discussion on two branches corrected, v3: reference adde