Spatially-resolved Radio-to-Far-infrared SED of the Luminous Merger Remnant NGC 1614 with ALMA and VLA

We present the results of Atacama Large Millimeter/Submillimeter Array (ALMA) 108, 233, 352, and 691 GHz continuum observations and Very Large Array (VLA) 4.81 and 8.36 GHz observations of the nearby luminous merger remnant NGC 1614. By analyzing the beam (1".0 * 1".0) and uv (> 45 k{\lambda}) matched ALMA and VLA maps, we find that the deconvolved source size of lower frequency emission (< 108 GHz) is more compact (420 pc * 380 pc) compared to the higher frequency emission (> 233 GHz) (560 pc * 390 pc), suggesting different physical origins for the continuum emission. Based on an SED model for a dusty starburst galaxy, it is found that the SED can be explained by three components, (1) non-thermal synchrotron emission (traced in the 4.81 and 8.36 GHz continuum), (2) thermal free-free emission (traced in the 108 GHz continuum), and (3) thermal dust emission (traced in the 352 and 691 GHz continuum). We also present the spatially-resolved (sub-kpc scale) Kennicutt-Schmidt relation of NGC 1614. The result suggests a systematically shorter molecular gas depletion time in NGC 1614 (average {\tau}_gas of 49 - 77 Myr and 70 - 226 Myr at the starburst ring and the outer region, respectively) than that of normal disk galaxies (~ 2 Gyr) and a mid-stage merger VV 114 (= 0.1 - 1 Gyr). This implies that the star formation activities in U/LIRGs are efficiently enhanced as the merger stage proceeds, which is consistent with the results from high-resolution numerical merger simulations.Comment: 10 pages, 6 figures, accepted for publication in PAS

Study of Doubly Heavy Baryon Spectrum via QCD Sum Rules

In this work, we calculate the mass spectrum of doubly heavy baryons with the diquark model in terms of the QCD sum rules. The interpolating currents are composed of a heavy diquark field and a light quark field. Contributions of the operators up to dimension six are taken into account in the operator product expansion. Within a reasonable error tolerance, our numerical results are compatible with other theoretical predictions. This indicates that the diquark picture reflects the reality and is applicable to the study of doubly heavy baryons.Comment: 23 pages, 9 figures, minor corrections in expression

Spatially resolved CO SLED of the Luminous Merger Remnant NGC 1614 with ALMA

We present high-resolution (1".0) Atacama Large Millimeter/submillimeter Array (ALMA) observations of CO (1-0) and CO (2- 1) rotational transitions toward the nearby IR-luminous merger NGC 1614 supplemented with ALMA archival data of CO (3-2), and CO (6-5) transitions. The CO (6-5) emission arises from the starburst ring (central 590 pc in radius), while the lower-$J$ CO lines are distributed over the outer disk ($\sim$ 3.3 kpc in radius). Radiative transfer and photon dominated region (PDR) modeling reveal that the starburst ring has a single warmer gas component with more intense far-ultraviolet radiation field ($n_{\rm{H_2}}$ $\sim$ 10$^{4.6}$ cm$^{-3}$, $T_{\rm{kin}}$ $\sim$ 42 K, and $G_{\rm{0}}$ $\sim$ 10$^{2.7}$) relative to the outer disk ($n_{\rm{H_2}}$ $\sim$ 10$^{5.1}$ cm$^{-3}$, $T_{\rm{kin}}$ $\sim$ 22 K, and $G_{\rm{0}}$ $\sim$ 10$^{0.9}$). A two-phase molecular interstellar medium with a warm and cold ($>$ 70 K and $\sim$ 19 K) component is also an applicable model for the starburst ring. A possible source for heating the warm gas component is mechanical heating due to stellar feedback rather than PDR. Furthermore, we find evidence for non-circular motions along the north-south optical bar in the lower-$J$ CO images, suggesting a cold gas inflow. We suggest that star formation in the starburst ring is sustained by the bar-driven cold gas inflow, and starburst activities radiatively and mechanically power the CO excitation. The absence of a bright active galactic nucleus can be explained by a scenario that cold gas accumulating on the starburst ring is exhausted as the fuel for star formation, or is launched as an outflow before being able to feed to the nucleus.Comment: 20 pages, 19 figures, 2 tables, accepted for publication in Ap

A New Approach for Analytic Amplitude Calculations

We present a method for symbolic calculation of Feynman amplitudes for processes involving both massless and massive fermions. With this approach fermion strings in a specific amplitude can be easily evaluated and expressed as basic Lorentz scalars. The new approach renders the symbolic calculation of some complicated physical processes more feasible and easier, especially with the assistance of algebra manipulating codes for computer.Comment: LaTex, no figure, to appear in PR

Forward and Backward Private DSSE for Range Queries

Due to its capabilities of searches and updates over the encrypted database, the dynamic searchable symmetric encryption (DSSE) has received considerable attention recently. To resist leakage abuse attacks, a secure DSSE scheme usually requires forward and backward privacy. However, the existing forward and backward private DSSE schemes either only support single keyword queries or require more interactions between the client and the server. In this paper, we first give a new leakage function for range queries, which is more complicated than the one for single keyword queries. Furthermore, we propose a concrete forward and backward private DSSE scheme by using a refined binary tree data structure. Finally, the detailed security analysis and extensive experiments demonstrate that our proposal is secure and efficient, respectively

Mapping IR Enhancements in Closely Interacting Spiral-Spiral Pairs. I. ISO~CAM and ISO~SWS Observations

Mid-infrared (MIR) imaging and spectroscopic observations are presented for a well defined sample of eight closely interacting (CLO) pairs of spiral galaxies that have overlapping disks and show enhanced far-infrared (FIR) emission. The goal is to study the star formation distribution in CLO pairs, with special emphasis on the role of 'overlap starbursts'. Observations were made with the Infrared Space Observatory (ISO) using the CAM and SWS instruments. The ISO~CAM maps, tracing the MIR emission of warm dust heated by young massive stars, are compared to new ground based H$\alpha$ and R-band images. We identify three possible subgroups in the sample, classified according to the star formation morphology: (1) advanced mergers (Arp~157, Arp~244 and Arp~299), (2) severely disturbed systems (Arp~81 and Arp~278), and (3) less disturbed systems (Arp~276, KPG 347 and KPG 426). Localized starbursts are detected in the overlap regions in all five pairs of subgroups (1) and (2), suggesting that they are a common property in colliding systems. Except for Arp~244, the 'overlap starburst' is usually fainter than the major nuclear starburst in CLO pairs. Star formation in 'less disturbed systems' is often distributed throughout the disks of both galaxies with no 'overlap starburst' detected in any of them. These systems also show less enhanced FIR emission, suggesting that they are in an earlier interaction stage than pairs of the other two subgroups where the direct disk collisions have probably not yet occurred.Comment: 27 pages text, 4 JPEG figures, 3 PS figures. To be accepted by ApJ. High quality figures (included in a PS file of the paper) can be found in http://spider.ipac.caltech.edu/staff/cxu/papers/ss_iso.ps.g

Local Luminosity Function at 15μm\mu m and Galaxy Evolution Seen by ISOCAM 15μm\mu m Surveys

A local luminosity function at 15$\mu m$ is derived using the bivariate (15$\mu m$ vs. 60$\mu m$ luminosity) method, based on the newly published ISOCAM LW3-band (15$\mu m$) survey of the very deep IRAS 60$\mu m$ sample in the north ecliptic pole region (NEPR). New IRAS 60$\mu m$ fluxes are obtained using the SCANPI/SUPERSCANPI software at the new ISOCAM positions of the sources in the sample. It is found to be in excellent agreement with the 15$\mu m$ local luminosity function published by Xu et al (1998), which is derived from the {\it predicted} 15$\mu m$ luminosities of a sample of IRAS 25$\mu m$ selected galaxies. Model predictions of number counts and redshift distributions based on the local luminosity function and assumptions of its evolution with the redshift are calculated and compared with the data of ISOCAM 15$\mu m$ surveys. Strong luminosity evolution on the order of $L\propto (1+z)^{4.5}$ is suggested in these comparisons, while pure density evolution can be ruled out with high confidence. The sharp peak at about 0.4mJy in the Euclidean normalized differential counts at 15$\mu m$ can be explained by the effects of MIR broadband emission features, eliminating the need for any hypothesis for a 'new population'. It is found that the contribution from the population represented by ISOCAM 15$\mu m$ sources can account for the entire IR/submm background, leaving little room for any missing 'new population' which can be significant energy sources of the IR/submm sky.Comment: 25 pages, 7 EPS figures. Accepted by Ap

Emission Features and Source Counts of Galaxies in Mid-Infrared

In this work we incorporate the newest ISO results on the mid-infrared spectral-energy-distributions (MIR SEDs) of galaxies into models for the number counts and redshift distributions of MIR surveys. A three-component model, with empirically determined MIR SED templates of (1) a cirrus/PDR component (2) a starburst component and (3) an AGN component, is developed for infrared (3--120\micron) SEDs of galaxies. The model includes a complete IRAS 25\micron selected sample of 1406 local galaxies ($z \leq 0.1$; Shupe et al. 1998a). Results based on these 1406 spectra show that the MIR emission features cause significant effects on the redshift dependence of the K-corrections for fluxes in the WIRE 25\micron band and ISOCAM 15\micron band. This in turn will affect deep counts and redshift distributions in these two bands, as shown by the predictions of two evolution models (a luminosity evolution model with $L\propto (1+z)^3$ and a density evolution model with $\rho\propto (1+z)^4$). The dips-and-bumps on curves of MIR number counts, caused by the emission features, should be useful indicators of evolution mode. The strong emission features at $\sim 6$--8\micron will help the detections of relatively high redshift ($z\sim 2$) galaxies in MIR surveys. On the other hand, determinations of the evolutionary rate based on the slope of source counts, and studies on the large scale structures using the redshift distribution of MIR sources, will have to treat the effects of the MIR emission features carefully. We have also estimated a 15\micron local luminosity function from the predicted 15\micron fluxes of the 1406 galaxies using the bivariate (15\micron vs. 25\micron luminosities) method. This luminosity function will improve our understanding of the ISOCAM 15\micron surveys.Comment: 24 pages, 14 EPS figures. Accepted by Ap