PROPERTIES AND KEPLERIAN ROTATION OF THE HOT CORE IRAS 20126+4104
We present Submillimeter Array (SMA) observations of the massive star-forming region IRAS 20126+4104 in the millimeter continuum and in several molecular line transitions. With the SMA data, we have detected nine molecular transitions, including deuterated hydrogen cyanide, CH{sub 3}OH, H{sub 2}CO, and HC{sub 3}N molecules, and imaged each molecular line. From the 1.3 mm continuum emission a compact millimeter source is revealed, which is also associated with H{sub 2}O, OH, and CH{sub 3}OH masers. Using a rotation temperature diagram, we derive that the rotational temperature and the column density of CH{sub 3}OH are 200 K and 3.7 Multiplication-Sign 10{sup 17} cm{sup -2}, respectively. The calculated results and analysis further indicate that a hot core coincides with IRAS 20126+4104. The position-velocity diagrams of H{sub 2}CO (3{sub 0,3}-2{sub 0,2}) and HC{sub 3}N (25-24) clearly present Keplerian rotation. Moreover, H{sub 2}CO (3{sub 0,3}-2{sub 0,2}) is found to trace the disk rotation for the first time.

title: SUBMILLIMETER ARRAY AND VERY LARGE ARRAY OBSERVATIONS IN THE HYPERCOMPACT H II REGION G35.58-0.03
abstract: The formation of hypercompact (HC) H II regions is an important stage in massive star formation. Spectral line and continuum observations can explore its dynamic conditions. We present high angular resolution observations carried out with the Submillimeter Array (SMA) and the Very Large Array (VLA) toward the HC H II region G35.58-0.03. With the 1.3?mm SMA and 1.3?cm VLA, we detected a total of about 25 transitions of 8 different species and their isotopologues (CO, CH3CN, SO2, CH3CCH, OCS, CS, H, and NH3). G35.58-0.03 consists of an HC H II core with electron temperature ?K, emission measure EM 1.9 ? 109?pc?cm?6, local volume electron density ne = 3.3 ? 105?cm?3, and a same width of radio recombination line FWHM? 43.2?km s?1 for both H30? and H38? at its intrinsic core size ~3714 AU. The H30? line shows evidence of an ionized outflow driving a molecular outflow. Based on the derived Lyman continuum flux, there should be an early-type star equivalent to O6.5 located inside the H II region. From the continuum spectral energy distribution from 3.6?cm, 2.0?cm, 1.3?cm, 1.3?mm and 0.85?mm to 0.45?mm, we distinguished the free-free emission (25% ~ 55%) from the warm dust component (75%?~ 45%) at 1.3?mm. The molecular envelope shows evidence of infall and outflow with an infall rate of 0.05 M ? yr?1 and a mass loss rate of 5.2 ? 10?3 M ? yr?1. The derived momentum (~0.05 M ? km s?1) is consistent between the infalling and outflowing gas per year. It is suggested that the infall is predominant and the envelope mass of dense core is increasing rapidly, but the accretion in the inner part might already be halted.

title: Molecular clumps and star formation associated with the infrared dust bubble N131
abstract: The aim is to explore the interstellar medium around the dust bubble N131 and search for signatures of star formation. 
Methods. We perform a multiwavelength study around the N131 with data taken from large-scale surveys of infrared observation with online archive. We present new observations of three CO J = 1 - 0 isotope variants from Purple Mountain Observatory 13.7 m telescope. We analyze the distribution of the molecular gas and dust in the environment of the N131. We use color-color diagrams to search for young stellar objects and identify exciting star candidates. 
Results. The kinematic distance of about 8.6 kpc has been adopted as the distance of the bubble N131 from the Sun in this work. We have found a ring of clouds in CO emission coincident with the shell of N131 seen in the Spitzer telescope images, and two giant elongated molecular clouds of CO emission appearing on opposite sides of the ringlike shell of N131. There is a cavity within bubble at 1.4 GHz and 24 {\mu}m. Seven IRAS point sources are distributed along the ringlike shell of the bubble N131. 15 exciting stars and 63 YSOs candidates have been found. The clustered class I and II YSOs are distributed along the elongated clouds in the line of sight.

title: The open cluster NGC 6823 and possible triggered star formation associated with SNR G59.5+0.1
abstract: We investigate the environment in the vicinity of the supernova remnant (SNR) G59.5+0.1 and identify all the young stellar objects (YSOs) around the SNR, to derive the physical properties, obtain insight into the star-formation history, and determine whether SNR G59.5+0.1 can trigger star formation in this region.  We perform the submillimeter/millimeter observations in CO lines toward the southeast of SNR G59.5+0.1 with the KOSMA 3 m Telescope. High values of the integrated CO line-intensity ratio RICO(3−2)/ICO(2−1) is identified as one good signature of the SNR-MC (molecular cloud) interacting system. To investigate the impact of SNR G59.5+0.1 on the process of star formation, we use GLIMPSE I catalog to select YSOs (including Class I and Class II sources).  The CO emission forming an arc-like shape and mid-infrared 8.28 μm emission are coincident with SNR G59.5+0.1, which ‐

title: Outflow and accretion detections in the young stellar object IRAS 04579+4703
abstract: We present Submillimeter Array observations of the young stellar object IRAS 04579+4703 in the 1.3 mm continuum and in the 12 CO(2−1), 13 CO(2−1), and C 18 O(2−1) lines. The 1.3 mm continuum image reveals a flattened structure with a mass of 13 M � . The 12 CO(2−1) line map and position-velocity diagram, together with the broad wing (full width = 30 km s −1 )o f the 12 CO(2−1) line, clearly show that there is an outflow motion, which originates from an embedded massive YSO in this region. The lengths of the blue-shifted and red-shifted lobes are 0.14 pc and 0.13 pc, respectively. The total gas mass, average dynamical timescale, and

title: Density matrix expansion for the MDI interaction
abstract: By assuming that the isospinand momentum-dependent MDI interaction has a form similar to the Gogny-like effective two-body interaction with a Yukawa finite-range term and the momentum dependence only originates from the finite-range exchange interaction, we determine its parameters by comparing the predicted potential energy density functional in uniform nuclear matter with what has been usually given and used extensively in transport models for studying isospin effects in intermediate-energy heavy-ion collisions as well as in investigating the properties of hot asymmetric nuclear matter and neutron star matter. We then use the density matrix expansion to derive from the resulting finite-range exchange interaction an effective Skyrme-like zero-range interaction with density-dependent parameters. As an application, we study the transition density and pressure at the inner edge of neutron star crusts using the stability conditions derived from the linearized Vlasov equation for the neutron star matter.

title: Charmonium production and elliptic flow in relativistic heavy-ion collisions
abstract: Using the two-component model for charmonium production, which includes contributions from both initial hard nucleon-nucleon scattering and from regeneration in the quark-gluon plasma, we have studied the nuclear modification factor RAA and elliptic flow v2 of J= in relativistic heavy-ion collisions. For the expansion dynamics of produced hot dense matter, we have introduced a schematic fire-cylinder model with its transverse acceleration determined from the pressure gradient inside the fire-cylinder and azimuthally anisotropic expansion parameterized to reproduce measuredv2 of light hadrons. We have assumed that light hadrons freeze out at the temperature of 120 MeV while charmonia at 160 MeV, similar to the kinetic and chemical freeze-out temperatures in the statistical model, respectively. For the properties of charmonia in the quark-gluon plasma, we have used the screening mass between their charm and anticharm quarks and their dissociation cross sections given by the perturbative QCD (pQCD) in the leading order and up to the next-to-leading order, respectively. For the relaxation time of charm and anticharm quarks in the quark-gluon plasma, we have also used the one calculated in the leading order pQCD. Modeling the effect of higher-order corrections in pQCD by introducing multiplicative factors to the dissociation cross sections of charmonia and the elastic scattering cross sections of charm and anticharm quarks, we have found that this effect is small for the RAA of J= as they suppress the number of initially produced J= but enhance the number of regenerated ones. The higher-order corrections increase, however, the v2 of J= . Our results thus suggest that thev2 of J= can play an important role in discriminating between J= production from initial hard collisions and from regeneration in the quark-gluon plasma.

title: Transition density and pressure in hot neutron stars
abstract: Using the momentum-dependent effective interaction (MDI) for nucleons, we have studied the transition density and pressure at the boundary between the inner crust and the liquid core of hot neutron stars. We find that their values are larger in neutrino-trapped neutron stars than in neutrino-free neutron stars. Furthermore, both are found to decrease with increasing temperature of a neutron star as well as increasing slope parameter of the nuclear symmetry energy, except that the transition pressure in neutrino-trapped neutron stars for the case of small symmetry energy slope parameter first increases and then decreases with increasing temperature. We have also studied the effect of the nuclear symmetry energy on the critical temperature above which the inner crust in a hot neutron star disappears and found that with increasing value of the symmetry energy slope parameter, the critical temperature decreases slightly in neutrino-trapped neutron stars but first decreases and then increases in neutrino-free neutron stars.

title: INCOMPRESSIBILITY OF ASYMMETRIC NUCLEAR MATTER
abstract: Using an isospin- and momentum-dependent modified Gogny (MDI) interaction, the Skyrme-Hartree-Fock (SHF) approach, and a phenomenological modified Skyrme-like (MSL) model, we have studied the incompressibility Ksat(δ) of isospin asymmetric nuclear matter at its saturation density. Our results show that in the expansion of Ksat(δ) in powers of isospin asymmetry δ, i.e., Ksat(δ) = K0 + Ksat,2δ2 + Ksat,4δ4 + O(δ6), the magnitude of the 4th-order Ksat,4 parameter is generally small. The 2nd-order Ksat,2 parameter thus essentially characterizes the isospin dependence of the incompressibility of asymmetric nuclear matter at saturation density. Furthermore, the Ksat,2 can be expressed as in terms of the slope parameter L and the curvature parameter Ksym of the symmetry energy and the third-order derivative parameter J0 of the energy of symmetric nuclear matter at saturation density, and we find the higher order J0 contribution to Ksat,2 generally cannot be neglected. Also, we have found a linear correlation between Ksym and L as well as between J0/K0 and K0. Using these correlations together with the empirical constraints on K0 and L, the nuclear symmetry energy Esym(ρ0) at normal nuclear density, and the nucleon effective mass, we have obtained an estimated value of Ksat,2 = -370 ± 120 MeV for the 2nd-order parameter in the isospin asymmetry expansion of the incompressibility of asymmetric nuclear matter at its saturation density.

title: Specific viscosity of neutron-rich nuclear matter from a relaxation time approach
abstract: The specific viscosity of neutron-rich nuclear matter is studied from the relaxation time approach using an isospin- and momentum-dependent interaction and the nucleon-nucleon cross sections taken as those from the experimental data modified by the in-medium effective masses as used in the isospin-dependent BoltzmannUehling-Uhlenbeck (IBUU) transport model calculations. The relaxation time of neutrons is larger while that of protons is smaller in neutron-rich nuclear matter compared with that in symmetric nuclear matter, and this leads to a larger specific viscosity in neutron-rich nuclear matter. In addition, the specific viscosity decreases with increasing temperature because of more frequent collisions and weaker Pauli blocking effect at higher temperatures. At lower temperatures the specific viscosity increases with increasing density due to the Pauli blocking effect, while at higher temperatures it slightly decreases with increasing density as a result of smaller in-medium effective masses at higher densities.