119242109
Molecular clumps and star formation associated with the infrared dust bubble N131
Aims. 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.
119215891
SUBMILLIMETER ARRAY AND VERY LARGE ARRAY OBSERVATIONS IN THE HYPERCOMPACT H II REGION G35.58-0.03
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.
119114895
The open cluster NGC 6823 and possible triggered star formation associated with SNR G59.5+0.1
Aims. 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. Methods. 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). Results. The CO emission forming an arc-like shape and mid-infrared 8.28 μm emission are coincident with SNR G59.5+0.1, which ‐ ‐
9281488
On Computing Upper Limits to Source Intensities
A common problem in astrophysics is determining how bright a source could be and still not be detected in an observation. Despite the simplicity with which the problem can be stated, the solution involves complicated statistical issues that require careful analysis. In contrast to the more familiar confidence bound, this concept has never been formally analyzed, leading to a great variety of often ad hoc solutions. Here we formulate and describe the problem in a self-consistent manner. Detection significance is usually defined by the acceptable proportion of false positives (background fluctuations that are claimed as detections, or Type I error), and we invoke the complementary concept of false negatives (real sources that go undetected, or Type II error), based on the statistical power of a test, to compute an upper limit to the detectable source intensity. To determine the minimum intensity that a source must have for it to be detected, we first define a detection threshold and then compute the probabilities of detecting sources of various intensities at the given threshold. The intensity that corresponds to the specified Type II error probability defines that minimum intensity and is identified as the upper limit. Thus, an upper limit is a characteristic of the detection procedure rather than the strength of any particular source. It should not be confused with confidence intervals or other estimates of source intensity. This is particularly important given the large number of catalogs that are being generated from increasingly sensitive surveys. We discuss, with examples, the differences between these upper limits and confidence bounds. Both measures are useful quantities that should be reported in order to extract the most science from catalogs, though they answer different statistical questions: an upper bound describes an inference range on the source intensity, while an upper limit calibrates the detection process. We provide a recipe for computing upper limits that applies to all detection algorithms.
118536957
Locating the inner edge of the neutron star crust using terrestrial nuclear laboratory data
Within both dynamical and thermodynamical approaches using the equation of state for neutron-rich nuclear matter constrained by the recent isospin diffusion data from heavy-ion reactions in the same subsaturation density range as the neutron star crust, the density and pressure at the inner edge separating the liquid core from the solid crust of neutron stars are determined to be $0.040 {\mathrm{fm}}^{\ensuremath{-}3}\ensuremath{\leqslant}{\ensuremath{\rho}}_{t}\ensuremath{\leqslant}0.065 {\mathrm{fm}}^{\ensuremath{-}3}$ and 0.01 MeV/${\mathrm{fm}}^{3}\ensuremath{\leqslant}{P}_{t}\ensuremath{\leqslant}0.26$ MeV/${\mathrm{fm}}^{3}$, respectively. These together with the observed minimum crustal fraction of the total moment of inertia allow us to set a new limit for the radius of the Vela pulsar significantly different from the previous estimate. It is further shown that the widely used parabolic approximation to the equation of state of asymmetric nuclear matter leads systematically to significantly higher core-crust transition densities and pressures, especially with stiffer symmetry energy functionals.
121568193
Energy determination at BEPC-II
The BEPC-II collider beam energy calibration system is discussed. The system is based on the Compton backscattering method. The expected precision of the electron and positron beam energy e determination is δ e / e ≈ 3 ⋅ 10 − 5 .
15860671
NUCLEAR CONSTRAINTS ON PROPERTIES OF NEUTRON STAR CRUSTS
The transition density ? t and pressure Pt at the inner edge separating the liquid core from the solid crust of neutron stars are systematically studied using a modified Gogny (MDI) and 51 popular Skyrme interactions within well established dynamical and thermodynamical methods. First of all, it is shown that the widely used parabolic approximation to the full equation of state (EOS) of isospin asymmetric nuclear matter may lead to huge errors in estimating the transition density and pressure, especially for stiffer symmetry energy functionals E sym(?), compared to calculations using the full EOS within both the dynamical and thermodynamical methods mainly because of the energy curvatures involved. Thus, fine details of the EOS of asymmetric nuclear matter are important for locating accurately the inner edge of the neutron star crust. Second, the transition density and pressure decrease roughly linearly with increasing slope parameter L of E sym(?) at normal nuclear matter density using the full EOS within both the dynamical and thermodynamical methods. It is also shown that the thickness, fractional mass, and moment of inertia of the neutron star crust are all very sensitive to the parameter L through the transition density ? t whether one uses the full EOS or its parabolic approximation. Moreover, it is shown that E sym(?) constrained in the same subsaturation density range as the neutron star crust by the isospin diffusion data in heavy-ion collisions at intermediate energies limits the transition density and pressure to 0.040 fm?3 ?? t ? 0.065 fm?3 and 0.01 MeV fm?3 ?Pt ? 0.26 MeV fm?3, respectively. These constrained values for the transition density and pressure are significantly lower than their fiducial values currently used in the literature. Furthermore, the mass-radius relation and several other properties closely related to the neutron star crust are studied by using the MDI interaction. It is found that the newly constrained ? t and Pt together with the earlier estimate of ?I/I>0.014 for the crustal fraction of the moment of inertia of the Vela pulsar impose a more stringent constraint of R ? 4.7 + 4.0M/M ? km for the radius R and mass M of neutron stars compared to previous studies in the literature.
119165305
INCOMPRESSIBILITY OF ASYMMETRIC NUCLEAR MATTER
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.