分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The first B-, V-, Rc-, and Ic-band light curves of CSS J022914.4+044340 are presented and analyzed. It is found that CSS J022914.4+044340 is a low mass ratio (0.198 +- 0.005) deep (63.7 +- 7.9%) contact binary, indicating that it has been already at the end evolutionary stage of tidally-locked evolution via magnetized wind. Because of the totally eclipsing character, the photometric solutions are reliable. The temperature and the metallicity are determined from the spectroscopic data as T = 5855 +- 15 K, and [Fe/H] = -0.842 +- 0.031, respectively. Based on the parallax of Gaia EDR3, the physical parameters of CSS J022914.4+044340 are estimated as M1 = 1.44 (+0.25,-0.22) solar mass, M2 = 0.29 (+0.05,-0.05) solar mass, R1 = 1.26 (+0.08,-0.06) solar radius, R2 = 0.65 (+0.03,-0.04) solar radius, L1 = 1.718 (+0.186,-0.191) solar luminosity, L2 = 0.416 (+0.039,-0.050) solar luminosity. Combined the fraction in light of the third body via the photometric solution (54%), the luminosity of the third body is estimated as 2.705 solar luminosity. The third body may be inferred as a subgiant. Thus, it is explained that why the primary component of CSS J022914.4+044340 has higher mass among the similar systems, and why its metallicity is so poor.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The cosmic distance duality relation (DDR) is constrained from the combination of type-Ia supernovae (SNe Ia) and strong gravitational lensing (SGL) systems using deep learning method. To make use of the full SGL data, we reconstruct the luminosity distance from SNe Ia up to the highest redshift of SGL using deep learning, then it is compared with the angular diameter distance obtained from SGL. Considering the influence of lens mass profile, we constrain the possible violation of DDR in three lens mass models. Results show that in the SIS model and EPL model, DDR is violated at high confidence level, with the violation parameter $\eta_0=-0.193^{+0.021}_{-0.019}$ and $\eta_0=-0.247^{+0.014}_{-0.013}$, respectively. In the PL model, however, DDR is verified within 1$\sigma$ confidence level, with the violation parameter $\eta_0=-0.014^{+0.053}_{-0.045}$. Our results demonstrate that the constraints on DDR strongly depend on the lens mass models. Given a specific lens mass model, DDR can be constrained at a precision of $\textit{O}(10^{-2})$ using deep learning.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The cosmic distance duality relation (DDR) is constrained from the combination of type-Ia supernovae (SNe Ia) and strong gravitational lensing (SGL) systems using deep learning method. To make use of the full SGL data, we reconstruct the luminosity distance from SNe Ia up to the highest redshift of SGL using deep learning, then it is compared with the angular diameter distance obtained from SGL. Considering the influence of lens mass profile, we constrain the possible violation of DDR in three lens mass models. Results show that in the SIS model and EPL model, DDR is violated at high confidence level, with the violation parameter $\eta_0=-0.193^{+0.021}_{-0.019}$ and $\eta_0=-0.247^{+0.014}_{-0.013}$, respectively. In the PL model, however, DDR is verified within 1$\sigma$ confidence level, with the violation parameter $\eta_0=-0.014^{+0.053}_{-0.045}$. Our results demonstrate that the constraints on DDR strongly depend on the lens mass models. Given a specific lens mass model, DDR can be constrained at a precision of $\textit{O}(10^{-2})$ using deep learning.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： We use the idea of repeat measurement to determine the mean value and error of light curve solution parameters of contact binaries. Our simulation is realized by the Monte Carlo algorithm and Wilson-Devinney code. This method can obtain the systematic and random error simultaneously. Within our 48 models, the systematic errors are smaller than the random errors in most case. According to the numerical calculations, it is found that the relative errors of photometric mass ratios are less than 1% for totally eclipsing contact binaries, while they are generally between 10% and 20% for partly eclipsing ones. The effect of third light on the errors of photometric solution is also investigated. With a third light, these errors are close to 10% for totally eclipsing contact binaries. Specially, it is better to set the third light to zero in flux if that light is very faint (e.g., less than 1% contribution in luminosity), because such faint third light will bring big errors to the light curve solutions.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Selective control of light is essential for optical science and technology with numerous applications. Nanophotonic waveguides and integrated couplers have been developed to achieve selective coupling and spatial control of an optical beam according to its multiple degrees of freedom. However, previous coupling devices remain passive with an inherently linear response to the power of incident light limiting their maximal optical selectivity. Here, we demonstrate nonlinear optical selectivity through selective excitation of individual single-mode nanolasers based on the spin and orbital angular momentum of light. Our designed nanolaser circuits consist of plasmonic metasurfaces and individual perovskite nanowires, enabling subwavelength focusing of angular-momentum-distinctive plasmonic fields and further selective excitation of single transverse laser modes in nanowires. The optically selected nanolaser with nonlinear increase of light emission greatly enhances the baseline optical selectivity offered by the metasurface from about 0.4 up to near unity. Our demonstrated nonlinear optical selectivity may find important applications in all-optical logic gates and nanowire networks, ultrafast optical switches, nanophotonic detectors, and on-chip optical and quantum information processing.
分类： 天文学 >> 天文学 提交时间： 2016-11-16
Chenzhou Cui
Ce Yu
Jian Xiao
Boliang He
Changhua Li
Dongwei Fan
Chuanjun Wang
Zhi Hong
Shanshan Li
Linying Mi
Wanghui Wan1
Zihuang Cao
Jiawei Wang
Shucheng Yin
Yufeng Fan
Jianguo Wang
Sisi Yang
Yin Ling
Hailong Zhang
Junyi Chen
摘要： As the cyber-infrastructure for Astronomical research from Chinese Virtual Observatory (China-VO) project, AstroCloud has been archived solid progresses during the last one year. Proposal management system and data access system are redesigned. Several new sub-systems are developed, including China-VO PaperData, AstroCloud Statics and Public channel. More data sets and application environments are integrated into the platform. LAMOST DR1, the largest astronomical spectrum archive was released to the public using the platform. The latest progresses will be introduced.
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