Search

Your search keyword '"Ma, Shuguo"' showing total 172 results
Start Over Author "Ma, Shuguo"
172 results on '"Ma, Shuguo"'

1. An X-Ray-dim 'Isolated' Neutron Star in a Binary?

Author

Lin, Jie, Li, Chunqian, Wang, Weiyang, Xu, Heng, Jiang, Jinchen, Yang, Daoye, Yaqup, Shahidin, Iskandar, Abdusamatjan, Ma, Shuguo, Niu, Hubiao, Esamdin, Ali, Liu, Shuai, Ramsay, Gavin, Vines, Jose I., Shi, Jianrong, and Xu, Renxin

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report the discovery of a dark companion to 2MASS J15274848+3536572 with an orbital period of 6.14 hr. Combining the radial velocity from LAMOST observations and modelling of the multiband light curve, one obtains a mass function of $\simeq 0.131~\rm M_{\odot}$, an inclination of $45.20^\circ{}^{+0.13^{\circ}}_{-0.20^{\circ}}$, and a mass ratio of $0.631^{+0.014}_{-0.003}$, which demonstrate the binary nature of the dark companion with mass of $0.98 \pm 0.03\rm M_{\odot}$ and a main-sequence K9-M0 star of $0.62 \pm 0.01~\rm M_{\odot}$. LAMOST optical spectra at a range of orbital phases reveal extra-peaked Halpha emission that suggests the presence of an accretion disk. The dark companion does not seem to be a white dwarf because of the lack of any observed dwarf nova outbursts in the long-term data archive, although a magnetic white dwarf cannot be excluded. Alternatively, we propose a scenario wherein the dark companion is a neutron star, but we have not detected radio pulsations or a single pulse from the system with the FAST (Five-hundred-meter Aperture Spherical radio Telescope), which hints at a radio-quiet compact object. If the dark companion is identified as a neutron star, it will be the nearest ( ~ 118 pc) and lightest neutron star. Furthermore, a kinematic analysis of the system's orbit in the galaxy may suggest its supernova event is associated with the radionuclide $^{60} \rm Fe$ signal observed from the deep-sea crusts. This radio-quiet and X-ray-dim nearby neutron star may resemble an XDINS (X-ray-dim isolated neutron star), but in a binary., Comment: 17 pages, 9 figures; Accepted for publication in ApJL

Published
2022
Full Text
View/download PDF

2. The Wide-field Photometric System of the Nanshan One-meter Telescope

Author

Bai, Chunhai, Feng, Guojie, Zhang, Xuan, Niu, Hubiao, Eskandar, Abdusamatjan, Pu, Guangxin, Ma, Shuguo, Liu, Jinzhong, Jiang, Xiaojun, Ma, Lu, Esamdin, Ali, and Wang, Na

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The Nanshan One-meter Wide-field Telescope (NOWT) is a prime focus system located at Nanshan Station of Xinjiang Astronomical Observatories (XAO). The field of view(FOV) was designed to 1.5 degree *1.5 degree, and Johnson-Cousins UBVRI system was chosen as the main Filter set. The telescope has been providing observation services for astronomers since Sept. 2013. Variable source searching and time-domain surveys are the main scientific goals. The system's test results are reported including linearity, dark current, bias, readout noise and gain of the CCD camera. The accurate instrumental calibration coefficients in UBVRI bands was driven with Landolt standard stars during photometric nights. Finally, the limiting magnitudes are given with signal-to-noise ratios and various exposure times for observers., Comment: 11 pages, 14 figures, 8tables

Published
2020
Full Text
View/download PDF

3. Physical Properties of H II Regions in M51 from Spectroscopic Observations

Author

Wei, Peng, Zou, Hu, Kong, Xu, Zhou, Xu, Hu, Ning, Lin, Zesen, Mao, Yewei, Lin, Lin, Zhou, Zhimin, Liu, Xiang, Ma, Shuguo, Ma, Lu, Zhong, Tuhong, Dang, Fei, Sun, Jiantao, and Lin, Xinkui

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

M51 and NGC 5195 is an interacting system that can be explored in great details with ground-based telescopes. The H II regions in M51 were observed using the 2.16 m telescope of the National Astronomical Observatories of the Chinese Academy of Sciences and the 6.5 m Multiple Mirror Telescope with spatial resolution of less than $\sim100$ pc. We obtain a total of 113 spectra across the galaxy and combine the literature data of Croxall et al. to derive a series of physical properties, including the gas-phase extinction, stellar population age, star formation rate (SFR) surface density, and oxygen abundance. The spatial distributions and radial profiles of these properties are investigated in order to study the characteristics of M51 and the clues to the formation and evolution of this galaxy. M51 presents a mild radial extinction gradient. The lower gas-phase extinction in the north spiral arms compared to the south arms are possibly caused by the past encounters with the companion galaxy of NGC 5195. A number of H II regions have the stellar age between 50 and 500 Myr, consistent with the recent interaction history by simulations in the literatures. The SFR surface density presents a mild radial gradient, which is ubiquitous in spiral galaxies. There is a negative metallicity gradient of $-0.08$ dex $R_{e}^{-1}$ in the disk region, which is also commonly found in many spiral galaxies. It is supported by the "inside-out" scenario of galaxy formation. We find a positive abundance gradient of 0.26 dex $R_{e}^{-1}$ in the inner region. There are possible reasons causing the positive gradient, including the freezing of the chemical enrichment due to the star-forming quenching in the bulge and the gas infall and dilution due to the pseudobulge growth and/or galactic interaction., Comment: 20 pages, 8 figures, 1 appendix, Accepted for publication in PASP. Comments and suggestions are welcome

Published
2020
Full Text
View/download PDF

4. TESS Observations of Seven Newly Identified High-amplitude δ Scuti Stars.

Author

Lv, Chenglong, Esamdin, Ali, Hasanzadeh, A., Ma, Shuguo, Yang, TaoZhi, and Karimov, Rivkat

Subjects
RR Lyrae stars, DISTRIBUTION (Probability theory), LIGHT curves, VARIABLE stars
Abstract

We report seven newly identified high-amplitude δ Scuti (HADS) stars. Among them, two stars (TIC 30977864 and TIC 387379145) exhibit pure radial pulsation without the excitation of non-radial modes. TIC 30977864 is classified as a double-mode HADS star, while the other four stars potentially show triple-mode HADS behavior. TIC 112682462 and TIC 255603395 closely resemble RR Lyrae stars based on their light curves, position in the period–luminosity diagram, and the period ratio diagram. However, without spectral observations, it is challenging to ascertain whether these two stars are HADS or RR Lyrae stars. TIC 281695001 exhibits a fundamental frequency amplitude smaller than that of the first overtone, suggesting the presence of intriguing phenomena that necessitate further analysis. We analyzed the relationship between metallicity and period using data provided by Netzel & Smolec. The metallicities of the 176 stars display a broad distribution ranging from −2.0 dex to 0.5 dex, with periods spanning 0.05 to 0.20 days. This random distribution of metallicities may contribute to the dispersion observed in the P1/P0 ratio. To derive more accurate conclusions, future spectroscopic observations of a larger sample of HADS stars are crucial. These observations will provide precise rotational velocities and more accurate determinations of metallicities. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

6. An X-Ray-dim “Isolated” Neutron Star in a Binary?

Author

Lin, Jie, primary, Li, Chunqian, additional, Wang, Weiyang, additional, Xu, Heng, additional, Jiang, Jinchen, additional, Yang, Daoye, additional, Yaqup, Shahidin, additional, Iskanda, Abdusamatjan, additional, Ma, Shuguo, additional, Niu, Hubiao, additional, Esamdin, Ali, additional, Liu, Shuai, additional, Ramsay, Gavin, additional, Vines, Jose I., additional, Shi, Jianrong, additional, and Xu, Renxin, additional

Published
2023
Full Text
View/download PDF

9. KIC 3440495: A Rapidly Rotating δ Scuti-γ Doradus Hybrid Pulsator in a Binary System

Author

Ma, Shuguo, primary, Esamdin, Ali, additional, Hernández, Antonio García, additional, Murphy, Simon J., additional, Lv, Chenglong, additional, Wei, Peng, additional, Rieutord, Michel, additional, Pascual-Granado, Javier, additional, Dang, Fei, additional, Niu, Hubiao, additional, Yang, TaoZhi, additional, Feng, Guojie, additional, Karimov, Rivkat, additional, and Tillayev, Yusuf, additional

Published
2022
Full Text
View/download PDF

12. KIC 5768203: A δ Sct Pulsator Modulated by Rotation and Spots

Author

Ma, Shuguo, primary, Ali, Esamdin, additional, Lv, Chenglong, additional, Wei, Peng, additional, Yang, TaoZhi, additional, Niu, Hubiao, additional, Nie, Jundan, additional, Liu, Junhui, additional, Zong, Peng, additional, Feng, Guojie, additional, and Zhang, Mengfan, additional

Published
2022
Full Text
View/download PDF

27. High catalytic activity of Au/Ce[O.sub.x]/Ti[O.sub.2](110) controlled by the nature of the mixed-metal oxide at the nanometer level

Author

Park, Joon B., Graciani, Jesus, Evans, Jaime, Stacchiola, Dario, Ma, Shuguo, Liu, Ping, Nambu, Akira, Sanz, Javier Fernandez, Hrbek, Jan, and Rodriguez, Jose A.

Subjects
Metallic oxides -- Properties, Catalysis -- Observations, Science and technology
Abstract

Mixed-metal oxides play a very important role in many areas of chemistry, physics, materials science, and geochemistry. Recently, there has been a strong interest in understanding phenomena associated with the deposition of oxide nanoparticles on the surface of a second (host) oxide. Here, scanning tunneling microscopy, photoemission, and density-functional calculations are used to study the behavior of ceria nanoparticles deposited on a Ti[O.sub.2](110) surface. The titania substrate imposes nontypical coordination modes on the ceria nanoparticles. In the Ce[O.sub.x]/Ti[O.sub.2](110) systems, the Ce cations adopt an structural geometry and an oxidation state (+3) that are quite different from those seen in bulk ceria or for ceria nanoparticles deposited on metal substrates. The increase in the stability of the [Ce.sup.3+] oxidation state leads to an enhancement in the chemical and catalytic activity of the ceria nanoparticles. The codeposition of ceria and gold nanoparticles on a Ti[O.sub.2](110) substrate generates catalysts with an extremely high activity for the production of hydrogen through the water-gas shift reaction ([H.sub.2]O + CO [right arrow] [H.sub.2] + C[O.sub.2]) or for the oxidation of carbon monoxide (2CO + [O.sub.2] [right arrow] 2C[O.sub.2]). The enhanced stability of the [Ce.sup.3+] state is an example of structural promotion in catalysis described here on the atomic level. The exploration of mixed-metal oxides at the nanometer level may open avenues for optimizing catalysts through stabilization of unconventional surface structures with special chemical activity. heterogeneous catalysis | imaging | structural properties | surface reactivity

Published
2009

29. Physical Properties of H ii Regions in M51 from Spectroscopic Observations

Author

Wei, Peng, primary, Zou, Hu, additional, Kong, Xu, additional, Zhou, Xu, additional, Hu, Ning, additional, Lin, Zesen, additional, Mao, Yewei, additional, Lin, Lin, additional, Zhou, Zhimin, additional, Liu, Xiang, additional, Ma, Shuguo, additional, Ma, Lu, additional, Zhong, Tuhong, additional, Dang, Fei, additional, Sun, Jiantao, additional, and Lin, Xinkui, additional

Published
2020
Full Text
View/download PDF

38. High catalytic activity of Au/CeO x/TiO 2(110) controlled by the nature of the mixed-metal oxide at the nanometer level

Author

Universidad de Sevilla. Departamento de Química Física, Ministerio de Ciencia e Innovación (MICIN). España, Park, Joon B., Graciani Alonso, Jesús, Evans, Jaime, Stacchiola, Dario, Ma, Shuguo, Liu, Ping, Nambu, Akira, Fernández Sanz, Javier, Hrbek, Jan, Rodríguez, José A., Universidad de Sevilla. Departamento de Química Física, Ministerio de Ciencia e Innovación (MICIN). España, Park, Joon B., Graciani Alonso, Jesús, Evans, Jaime, Stacchiola, Dario, Ma, Shuguo, Liu, Ping, Nambu, Akira, Fernández Sanz, Javier, Hrbek, Jan, and Rodríguez, José A.

Abstract

Mixed-metal oxides play a very important role in many areas of chemistry, physics, materials science, and geochemistry. Recently, there has been a strong interest in understanding phenomena associated with the deposition of oxide nanoparticles on the surface of a second (host) oxide. Here, scanning tunneling microscopy, photoemission, and density-functional calculations are used to study the behavior of ceria nanoparticles deposited on a TiO2(110) surface. The titania substrate imposes nontypical coordination modes on the ceria nanoparticles. In the CeO x/TiO 2(110) systems, the Ce cations adopt an structural geometry and an oxidation state (+3) that are quite different from those seen in bulk ceria or for ceria nanoparticles deposited on metal substrates. The increase in the stability of the Ce 3+ oxidation state leads to an enhancement in the chemical and catalytic activity of the ceria nanoparticles. The codeposition of ceria and gold nanoparticles on a TiO 2(110) substrate generates catalysts with an extremely high activity for the production of hydrogen through the water-gas shift reaction (H 2O + CO → H 2 + CO 2) or for the oxidation of carbon monoxide (2C0 + O 2→2CO 2). The enhanced stability of the Ce 3+ state is an example of structural promotion in catalysis described here on the atomic level. The exploration of mixed-metal oxides at the nanometer level may open avenues for optimizing catalysts through stabilization of unconventional surface structures with special chemical activity.

Published
2009

Catalog

Books, media, physical & digital resources
See catalog results