Lei Qian

Lei Qian
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Astrophysics of Galaxies (10)
 
Astrophysics (3)
 
Instrumentation and Methods for Astrophysics (3)
 
Solar and Stellar Astrophysics (2)
 
Cosmology and Nongalactic Astrophysics (1)
 
General Relativity and Quantum Cosmology (1)
 
Physics - Accelerator Physics (1)
 
High Energy Astrophysical Phenomena (1)

Publications Authored By Lei Qian

2017Apr
Authors: Derek Ward-Thompson, Kate Pattle, Pierre Bastien, Ray S. Furuya, Woojin Kwon, Shih-Ping Lai, Keping Qiu, David Berry, Minho Choi, Simon Coudé, James Di Francesco, Thiem Hoang, Erica Franzmann, Per Friberg, Sarah F. Graves, Jane S. Greaves, Martin Houde, Doug Johnstone, Jason M. Kirk, Patrick M. Koch, Jungmi Kwon, Chang Won Lee, Di Li, Brenda C. Matthews, Joseph C. Mottram, Harriet Parsons, Andy Pon, Ramprasad Rao, Mark Rawlings, Hiroko Shinnaga, Sarah Sadavoy, Sven van Loo, Yusuke Aso, Do-Young Byun, Eswariah Chakali, Huei-Ru Chen, Mike C. -Y. Chen, Wen Ping Chen, Tao-Chung Ching, Jungyeon Cho, Antonio Chrysostomou, Eun Jung Chung, Yasuo Doi, Emily Drabek-Maunder, Stewart P. S. Eyres, Jason Fiege, Rachel K. Friesen, Gary Fuller, Tim Gledhill, Matt J. Griffin, Qilao Gu, Tetsuo Hasegawa, Jennifer Hatchell, Saeko S. Hayashi, Wayne Holland, Tsuyoshi Inoue, Shu-ichiro Inutsuka, Kazunari Iwasaki, Il-Gyo Jeong, Ji-hyun Kang, Miju Kang, Sung-ju Kang, Koji S. Kawabata, Francisca Kemper, Gwanjeong Kim, Jongsoo Kim, Kee-Tae Kim, Kyoung Hee Kim, Mi-Ryang Kim, Shinyoung Kim, Kevin M. Lacaille, Jeong-Eun Lee, Sang-Sung Lee, Dalei Li, Hua-bai Li, Hong-Li Liu, Junhao Liu, Sheng-Yuan Liu, Tie Liu, A-Ran Lyo, Steve Mairs, Masafumi Matsumura, Gerald H. Moriarty-Schieven, Fumitaka Nakamura, Hiroyuki Nakanishi, Nagayoshi Ohashi, Takashi Onaka, Nicolas Peretto, Tae-Soo Pyo, Lei Qian, Brendan Retter, John Richer, Andrew Rigby, Jean-François Robitaille, Giorgio Savini, Anna M. M. Scaife, Archana Soam, Motohide Tamura, Ya-Wen Tang, Kohji Tomisaka, Hongchi Wang, Jia-Wei Wang, Anthony P. Whitworth, Hsi-Wei Yen, Hyunju Yoo, Jinghua Yuan, Chuan-Peng Zhang, Guoyin Zhang, Jianjun Zhou, Lei Zhu, Philippe André, C. Darren Dowell, Sam Falle, Yusuke Tsukamoto

We present the first results from the B-fields In STar-forming Region Observations (BISTRO) survey, using the Sub-millimetre Common-User Bolometer Array 2 (SCUBA-2) camera, with its associated polarimeter (POL-2), on the James Clerk Maxwell Telescope (JCMT) in Hawaii. We discuss the survey's aims and objectives. We describe the rationale behind the survey, and the questions which the survey will aim to answer. Read More

We present 2.5-square-degree C$_{2}$H N=1-0 and N$_2$H$^+$ J=1-0 maps of the $\rho$ Ophiuchi molecular cloud complex. These are the first large-scale maps of the $\rho$ Ophiuchi molecular cloud complex with these two tracers. Read More

In order to ensure the beam quality and meet the requirements introduced by the BEPCII storage ring, the beam energy feedback system has been developed at the exit of the linac. This paper describes the implementation and commissioning of this system in detail. The energy feedback system consists of an energy measurement unit, an application software and an execution unit. Read More

We have developed an iterative procedure to systematically combine the millimeter and submillimeter images of OB cluster-forming molecular clouds, which were taken by ground based (CSO, JCMT, APEX, IRAM-30m) and space telescopes (Herschel, Planck). For the seven luminous ($L$$>$10$^{6}$ $L_{\odot}$) Galactic OB cluster-forming molecular clouds selected for our analyses, namely W49A, W43-Main, W43-South, W33, G10.6-0. Read More

The inner boundary of a black hole accretion disk is often set to the marginally stable circular orbit (or the innermost stable circular orbit, ISCO) around the black hole. It is important for the theories of black hole accretion disks and their applications to astrophysical black hole systems. Traditionally, the marginally stable circular orbit is obtained by considering the equatorial motion of a test particle around a black hole. Read More

The core velocity dispersion (CVD) is a potentially useful tool for studying the turbulent velocity field of molecular clouds. CVD is based on centroid velocities of dense gas clumps, thus is less prone to density fluctuation and reflects more directly the cloud velocity field. Prior work demonstrated that the Taurus molecular cloud CVD resembles the well-known Larson's linewidth-size relation of molecular clouds. Read More

We have identified outflows and bubbles in the Taurus molecular cloud based on the $\sim 100$ deg$^2$ Five College Radio Astronomy Observatory $^{12}$CO(1-0) and $^{13}$CO(1-0) maps and the Spitzer young stellar object catalogs. In the main 44 deg$^2$ area of Taurus we found 55 outflows, of which 31 were previously unknown. We also found 37 bubbles in the entire 100 deg$^2$ area of Taurus, all of which had not been found before. Read More

The Five-hundred-meter Aperture Spherical Radio Telescope (FAST) is supported by a cable-net structure, whose change in form leads to a stress range of approximately 500MPa. This stress range is more than twice the standard authorized value. The cable-net structure is thus the most critical and fragile part of the FAST reflector system. Read More

In the standard model of particle physics, photons are mass-less particles with a particular dispersion relation. Tests of this claim at different scales are both interesting and important. Experiments in territory labs and several exterritorial tests have put some upper limits on photon mass, e. Read More

Stars are born in dense cores of molecular clouds. The core mass function (CMF), which is the mass distribution of dense cores, is important for understanding the stellar initial mass function (IMF). We obtained 350 $\mu$m dust continuum data using the SHARC-II camera at the Caltech Submillimeter Observatory (CSO) telescope. Read More

Young stars form in molecular cores, which are dense condensations within molecular clouds. We have searched for molecular cores traced by $^{13}$CO $J=1\to 0$ emission in the Taurus molecular cloud and studied their properties. Our data set has a spatial dynamic range (the ratio of linear map size to the pixel size) of about 1000 and spectrally resolved velocity information, which together allow a systematic examination of the distribution and dynamic state of $^{13}$CO cores in a large contiguous region. Read More

Five-hundred-meter Aperture Spherical radio Telescope (FAST) is a Chinese mega-science project to build the largest single dish radio telescope in the world. Its innovative engineering concept and design pave a new road to realize a huge single dish in the most effective way. FAST also represents Chinese contribution in the international efforts to build the square kilometer array (SKA). Read More

It was suggested by several authors that hypothetical primordial black holes (PBHs) may contribute to the dark matter in our Galaxy. There are strong constraints based on the Hawking evaporation that practically exclude PBHs with masses m~1e15-1e16g and smaller as significant contributors to the Galactic dark matter. Similarly, PBHs with masses greater than about 1e26g are practically excluded by the gravitational lensing observation. Read More

The disk-corona evaporation model naturally interprets many observational phenomena in black hole X-ray binaries, such as the truncation of an accretion disk and the spectral state transitions. On the other hand, magnetic field is known to play an important role in transporting angular momentum and producing viscosity in accretion flows. In this work, we explicitly take the magnetic field in the accretion disk corona into account and numerically calculate the coronal structure on the basis of our two-temperature evaporation code. Read More

The linearly polarized millimeter and sub-millimeter emission in Sagittarius A* is produced within 10 Schwarzschild radii of the supermassive black hole at the Galactic Center and may originate from a hot magnetized accretion disk, where electrons are heated efficiently by turbulent plasma waves. In such a scenario, the flux density and polarization are very sensitive to the electron heating rate and the inclination angle of disk, respectively, and the major axis of the sub-millimeter intrinsic polarization, which is aligned with the rotation axis of the disk, is perpendicular to the major axis of the polarized near-infrared emission. In combination with MHD simulations, which study the properties of the magnetic field and viscous stresses, the current spectral and polarization measurements give tight constraints on the model parameters. Read More