The pairwise velocity difference of over 2000 BHB stars in the Milky Way halo

Models of hierarchical galaxy formation predict that the extended stellar halos of galaxies like our Milky Way show a great deal of sub-structure, arising from disrupted satellites. Spatial sub-structure is directly observed, and has been quantified, in the Milky Way＇s stellar halo. Phase-space conservation implies that there should be sub-structure in position-velocity space. Here, we aim to quantify such position-velocity sub-structure, using a state-of-the art data set having over 2000 blue horizontal branch （BHB） stars with photometry and spectroscopy from SDSS. For stars in dynamically cold streams （＂young＂ streams）, we expect that pairs of objects that are physically close also have similar velocities. Therefore, we apply the well-established ＂pairwise velocity difference＂ （PVD） statistic （｜ △Vlos ｜） （△r）, where we expect （｜ △Vlos ｜） to drop for small separations At. We calculate the PVD for the SDSS BHB sample and find 〈｜ △Vlos ｜〉（△r） ≈ const., i.e. no such signal. By making mock-observations of the simulations by Bullock ＆ Johnston and applying the same statistic, we show that for individual, dynamically young streams, or assemblages of such streams, （｜ △Vlos ｜） drops for small distance separations At, as qualitatively expected. However, for a realistic complete set of halo streams, the pair-wise velocity difference shows no signal, as the simulated halos are dominated by ＂dynamically old＂ phase-mixed streams. Our findings imply that the sparse sampling and the sample sizes in SDSS DR6 are still insufficient to use the position-velocity sub-structure for a stringent quantitative data-model comparison. Therefore, alternate statistics must be explored and much more densely sampled surveys, dedicated to the structure of the Milky Way, such as LAMOST, are needed.

从阐释学视角看文化意象的翻译——从“the Milky Way”译法之争谈起

文化的差异性造就了文化意象的独特性，文化意象的翻译也逐渐成了文学翻译中一个重要的课题，足以引起翻译研究者的重视。作者首先扼要介绍赵景深译“牛奶路”之争，撇开其中的政治原因以及翻译责任感等因素，从阐释学角度解读文化意象不同翻译的现象，最后提出对文化意象翻译的个人见解。目的是从阐释学角度分析文化意象的理解以及翻译，希望能给译学界广大同仁提供一个新的视角。

Periodic Signals of the Milky Way Concealed in Terrestrial Sedimentary Basin Fills and in Planetary Magmatism?

Long periodic geodynamic processes with durations between 150 and 600 Million years appear to be in phase with similar galactic cycles, caused by the path of the solar system through the spiral arms of the Milky Way. This path is assumed by some authors to cause climate change due to cosmic ray fluctuations, affecting the cloud formation and the related albedo of the Earth, which periodically lead to glaciations every 150 Ma. With the glaciations, the sea level fluctuates accordingly. Subsequently, the varying sizes of shallow seas are causing periodic changes of the Moon’s?tidal dissipation, which affects presumably other geodynamic processes on the Earth. The Moon?may therefore synchronize directly or indirectly long periodic Phanerozoic cycles (sea level, orogeny, magmatism, sedimentation, etc.) with the Milky Way. As sea level fluctuations, orogeny, sedimentation and magmatism can be described as members of a geodynamic feedback system;no apparent reasons appear to be required to assign a cause of the cyclicity to agents outside of the?galactic-climatically synchronized Earth-Moon system. However, recent observations of young?volcanism on the near Earth terrestrial planets may require a new understanding. Magmatic/volcanic episodes on Venus, Mars and Mercury as well as on the Earth’s Moon are apparently contemporaneous thermal events accompanying increased magmatic/volcanic activities on the?Earth,?following a 300 myr cycle. Therefore, a collateral galactic thermal source within the Milky Way?appears to be needed that only affects the interior of the planets without any recognizable direct?effect on life and geology on the Earth. The search for such a source may lead to astrophysical?questions, related to a spiral arm affected distribution of dark energy, dark matter or even specific?neutrino sources. However, all possible astrophysical answers are outside of the author’s competence.

Arm Tangents and the Spiral Structure of the Milky Way—The Age Gradient

From the Sun, a look at the edge of each spiral arm in our Milky Way (seen tangentially, along the line of sight) can yield numerous insights. Using different arm tracers (dust, masers, synchrotron emission, CO gas, open star clusters), we observe here for the first time an age gradient (about 12 ± 2 Myrs/kpc), much as predicted by the density wave theory. This implies that the arm tracers are leaving the dust lane at a relative speed of about 81 ± 10 km/s. We then compare with recent optical data obtained from the Gaia satellite, pertaining to the spiral arms.

Superposing the Magnetic Spiral Structure of the Milky Way, on the Stellar Spiral Arms—Matching the Unique Galactic Magnetic Field Reversal Zone with Two Galactic Spiral Arm Segments

To pinpoint the peak location of the synchrotron total intensity emission in a spiral arm, we use a map of the spiralarm locations (from the observed arm tangent). Thus in a typical spiral arm in Galactic Quadrant I, we find the peak of the synchrotron radiation to be located about 220 ± 40 pc away from the inner arm edge (hot dust lane) inside the spiral arm. While most of the galactic disk has a clockwise large-scale magnetic field, we make a statistical analysis to delimitate more precisely the smaller reverse annulus with a counterclockwise galactic magnetic field. We find an annulus width of 2.1 ± 0.3 kpc (measured along the Galactic radius), located from 5.5 to 7.6 kpc from the Galactic Center). The annulus does not overlay with a single spiral arm—it encompasses segments of two different spiral arms. Using a recent delineation of the position of spiral arms, the field-reversed annulus is seen to encompass the Crux-Centaurus arm (in Galactic Quadrant IV) and the Sagittarius arm (in Galactic Quadrant I). Thus the full Sagittarius-Carina arm is composed of: 1) a Sagittarius arm (in Galactic quadrant I) with a counterclockwise magnetic field, and 2) a Carina arm (in Galactic Quadrant IV) with a clockwise magnetic field. Also the full Scutum-Crux-Centaurus arm is composed of: 1) a Scutum arm (in Galactic Quadrant I) with a clockwise magnetic field, and 2) a Crux-Centaurus arm (in Galactic Quadrant IV) with a counterclockwise magnetic field. Arm segments do not all have the same magnetic field direction. For completeness, we display 6 known magnetised advancing supershells around the Sun (within 400 pc), pushing out the interstellar magnetic field.

A Synthesis of Fundamental Parameters of Spiral Arms, Based on Recent Observations in the Milky Way

Recent advances in the position and shape of each spiral arm in the Milky Way (pitch angle, shape, number, inter-arm separation at the Sun) are evaluated and compared, and a statistical analysis yields an updated idealized Galactic map. Earlier tabular results were published in five blocks of 15 to 20 each, covering 1980 to 2007 [1-4]. This paper presents the latest two blocks, each between 15 and 20 entries of published spiral arm researches since 2008. Using this revised Galactic map, and a discussion on the width of the Sagittarius arm (major or minor or equal), an interpretation of orbital streamlines for the gas and magnetic fields is presented for 2 major arms and for 4 major arms in the Milky Way. Our interpretation for all the recent data favors the following: a four-arm non-circular spiral pattern for the Milky Way;the Sagittarius arm being likely an equal arm;the inter-arm separation at the Sun’s location converging near 3.0 kpc. We emphasize that these conclusions encompass all the data, and thus can vary somewhat from the results of data obtained from a single filter (only CO data, say).

Kinematic Structure of the Milky Way Galaxy, Near the Spiral Arm Tangents

We compare the observed radial velocity of different arm tracers, taken near the tangent to a spiral arm. A slight difference is predicted by the density wave theory, given the shock predicted at the entrance to the inner spiral arm. In many of these spiral arms, the observed velocity offset confirms the prediction of the density wave theory (with a separation between the maser velocity and the CO gas peak velocity, of about 20 km/s)—when the observed offset is bigger than the error estimates.

从Milky Way的翻译看文化意象的失落与歪曲

从赵景深对Milky Way译为"牛奶路"到该词汉译中遇到的一系列问题,反映出文学翻译中对文化意象的翻译存在着失落和歪曲现象。了解这种现象可以帮助译者在翻译过程中对原文中含有的文化意象进行充分完整的思考,找出最恰当的翻译方式。

Center of Milky Way Galaxy

In 2013, World-Universe Model (WUM) made one of the most important predictions: “Macroobjects of the World have cores made up of the discussed DM (Dark Matter) particles. Other particles, including DM and baryonic matter, form shells surrounding the cores” [1]. Prof. R. Genzel and A. Ghez confirmed this prediction: “The Discovery of a Supermassive Compact Object at the Centre of Our Galaxy” (Nobel Prize in Physics 2020). On May 12, 2022, astronomers, using the Event Horizon Telescope, released the first image of the accretion disk around the Sagittarius A* (Sgr A*) produced using a worldwide network of radio observatories made in April 2017. These observations were obtained by a global array of millimeter wavelength telescopes and analyzed by an international research team that now numbers over 300 people, which claimed that Sgr A* is a Supermassive Black Hole (SBH). In the present paper, we analyze these results in frames of WUM. Based on the totality of all accumulated experimental results for the Center of the Milky Way Galaxy we conclude that Sgr A* is the DM Core of our Galaxy.

Extinction of Light in the Galactic Halo: First Observational Evidence of the Interaction of Light and Dark Matter

We study the distribution of quasars on the celestial sphere according to ground-based SDSS and space-based WISE and Gaia observations. All distributions as a function of galactic latitude, b, exhibit a decrease in quasar frequency well outside the dust in and near the galactic plane. We prove that the observed decrease in quasar frequency at high galactic latitudes is not accompanied by reddening, meaning that it can not be caused by dust. The scattering of light by the circumgalactic gas is negligible because the Thomson scattering cross section is very small. We conclude the observed scattering of light must be caused by dark matter in the galactic halo. We determine the mass and charge of dark matter particles. If the dark matter particle is a fermion its mass, mDMand charge eDM=δe, where e is the elementary charge are: mDM=3.2×10−2eV and δ=3.856×10−5. If however the dark matter particle is spinless then: mDM=0.511eV and δ=2.132×10−4. These values for the charge of a dark matter particle are orders of magnitude higher than the upper limit of the neutrino charge according to laboratory experiments. Consequently, dark matter particles are not charged neutrinos. Since dark matter particles are charged, they must emit and absorb electromagnetic radiation. However, PDM~δ2, or: PDM~1.487×10−9Pe, where Peis the power output of a single electron.

Preface: The LAMOST Galactic surveys and early results

By the time of this writing, the ongoing LAMOST Galactic surveys have collected approximately 4.5 million stellar spectra with signal-to-noise ratios better than 10 per pixel. This special issue is devoted to early results from the surveys, mostly based on the LAMOST Data Release 1 （DR1; Luo et al., this volume） that contains data secured by May 2013, the end of the first year of regular surveys, al- though a few studies have made use of data collected in the second year of regular surveys. LAMOST DR1 was released to the Chinese astronomical community and international partners in August 2013 and made public to the whole world in March 2015. Here we briefly review the scope and motivation, data reduction and release, as well as early results of the surveys. As the project advances, one can expect that these surveys will yield an exquisite description of the distribution, kinematics and chemistry of Galactic stellar populations, especially those within a few kpc of the Sun, a robust measurement of the local dark matter density, and, consequently, shed light on how our Galaxy, and other galaxies in general, form and evolve.

A New View of the Mass Extinctions and the Worldwide Floods

In this study, the reasons for mass extinction in Jurassic were investigated. It was shown that galactic compression led to the activation of terrestrial nuclear reactors, which in turn led to the changes in tectonic activity, volcano eruptions, LIPs, MORBs, paleoclimate change, drift of continents, narrowing of the Earth, worldwide floods, tsunami, changes in mantle and core structures, in magnetic fields and in sedimentary isotopes. It was shown that the mass extinctions occurred during worldwide floods, caused by the narrowing of the Earth at the time of galactic gravitational compression. It was shown that the average statistical altitude distribution of dinosaurs has a bimodal distribution and corresponds to permanent migrations between the plains and the hills. It has been suggested that the skeletons of dinosaurs are well preserved as a result of covering the bodies of dinosaurs with mud flows of coastal sediments and the soil layers at worldwide tsunami. It was formulated the requirement to paleontology, consisting in the obligatory registration of altitudes of the actual place of the fossils found. The simple explanation of the presence of boundaries in the structure of the Earth is given: the 40K nuclear layer corresponds to the boundary between upper and lower mantle;the 137Cs layer located on the boundary between the lower mantle and the outer core;the Th-U nuclear layer is a border between outer and inner core. The previously abstract theories of subduction and continents drift have a clear and obvious physical sense. It was shown that the standard geological table is a registration book of galactic events during Paleozoic. It is proposed to restore the structure of the galactic arms by the geological deposits on the Earth. It was suggested to create the stations on elevated hills for rescue and regeneration of biological forms in the future.

Cosmic Contributions to the Deposition of Petroleum Source Rocks: Review and Analysis

The development of globally distributed Phanerozoic petroleum source rocks is concentrated on time intervals, which correlate convincingly with climatic driven glaciation epochs of Earth’s history, repeated every 150 million years, and during sea level high stands and maxima of global magmatism with a period of 300 million years. The 150 million year periodicity appears to be related to the path of the solar system through the spiral arms of the Milky Way and the 300 million year periodicity to changes of the spiral system. The spiral arms are preferred birth places of new stars, of which the larger ones have only smaller lifespans. Their preliminary deaths ended with explosions and selectively with the development of so-called white dwarfs, neutron stars or black holes. The times of the explosions of intermediate (sun-like) stars can be determined by measuring the present brightness of the dwarfs. Not surprisingly the last two maxima of recordable near solar system star explosions took place during the presumably spiral arms driven glacial epochs in Eocene to present and Upper Jurassic times. Such near solar system star explosions may have been the source of intense neutrino showers, cosmic rays and star dust. This dust contained all kinds of chemical elements, including phosphorus and uranium. Such cosmic phosphorus may have supported, through fertilizing, the distribution of life on Earth additionally to local phosphorus resources via bloom of biota in lakes and oceans and the enhanced growth of plants on land across all climatic zones. Subsequently it maintained the development of petroleum source rocks of all organic matter types within black shales and coals. Via the distribution of remnants of exploding stars—mainly white dwarfs, but neutron stars and black holes have to be counted as well—a cosmic contribution can therefore casually linked to the deposition of petroleum source rocks on Earth, not only purely correlatively by their contemporaneous appearances.

The LEGUE disk targets for LAMOST's pilot survey

We describe the target selection algorithm for the low latitude disk por- tion of the LAMOST Pilot Survey, which aims to test systems in preparation for the LAMOST spectroscopic survey. We use the PPMXL astrometric catalog, which provides positions, proper motions, B/R/I magnitudes （mostly） from USNO-B and d/H/Ks from the Two Micron All Sky Survey （2MASS） as well. We chose eight plates along the Galactic plane, in the region 0° 〈 α° 〈 67° and 42° 〈 δ 〈 59°, which cover 22 known open clusters with a range of ages. Adjacent plates may have some small overlapping area. Each plate covers an area of 2.5° in radius, with its cen- tral star （for the Shack-Hartmann guider） brighter than 8th magnitude. For each plate, we create an input catalog in the magnitude range 11.3 〈 Imag 〈 16.3 and Bmag available from PPMXL. The stars are selected to satisfy the requirements of the fiber positioning system and have a uniform distribution in the I vs. B - I color-magnitude diagram. Our final input catalog consists of 12 000 objects on each of eight plates that are observable during the winter observing season from the Xinglong Station of the National Astronomical Observatory of China.

Frequency Decay through Electromagnetic Radiation Absorption and Re-Emission by Inter-Galactic Dark Matter as an Alternate Explanation for the Hubble Constant

There is an alternate cause for the decay rate defined by Edwin Hubble’s Cosmological Constant Theory. It can be proposed because inward motion is observed in the local Galaxies||Star groups around the Milky Way. The recession velocity of Galaxies farther out of is reasoned entirely from the increasing redshift in the frequency. The smaller the image of observed Galaxy/Cluster objects, the greater the downward shift in frequency of all Electro-Magnetic signals [EM]. An alternate cause for that downward shift could be through the absorption and re-emission through matter, leading to the absorption of some fraction of the energy quanta. There is nowhere in our Local Universe that is both absolutely devoid of matter and the continual formation of objects of all scales. If redshift was because of space expansion, it would increase the distance that signal had to travel. So a signal from GN-z11 stellar structure at 13.4 billion light years [LY] would take 13.4 billion years to travel. Assuming 13.8 billion years since the Big Bang would mean GN-z11 object travelled 13.4 billion LY in 400 million years. A current value for the Hubble constant is: H0=(67.8 ± 0.77) km s -1 Mpc -1 a frequency is shift of 67.8/c over a single Mpc. An alternate expression would be a shift factor 2.261560E-5 over a distance of 3.08567E22 m or a redshift of 7.32923E-28 over a metre because of passage through a medium. Dark matter is a currently accepted phenomenon. It is proposed that properties include redshift’s all normal matters that are put upon EM||Boson signals at the fraction stated above. The signal reduction|| frequency distortion happens at a quantum level for each occurrence, and so is not detectable until passage through millions of LY of Dark Matter. Support for this alternate supposition is reasoned from the fact that the M31 Galaxy and the NGC 300 Galaxy are at distances inconsistent with their Hubble recession velocity.

银河系双星团及星团群研究进展

疏散星团是研究恒星形成和演化理论的理想实验室,然而星团的形成模式仍是一个基本但未解决的问题。为了深入探讨星团的形成与演化模式,首先需要从观测上证认出具有物理联系的双星团或星团群系统。开展双星团及星团群性质的研究可以为深入理解恒星等级成团形成的模式提供重要线索;此外,双星团与星团群为研究同一片分子云中星团的形成与演化模式提供了绝佳的机会,并有助于理解星团和母分子云在形态及运动学特性之间的联系。从双星团及星团群的样本甄选和形成机制等出发,简单介绍银河系双星团及星团群的研究历史,着重讨论了Gaia时代该领域的研究近况。

The mass of our Milky Way

We perform an extensive review of the numerous studies and methods used to determine the total mass of the Milky Way.We group the various studies into seven broad classes according to their modeling approaches.The classes include:i)estimating Galactic escape velocity using high velocity objects;ii)measuring the rotation curve through terminal and circular velocities;iii)modeling halo stars,globular clusters and satellite galaxies with the spherical Jeans equation and iv)with phase-space distribution functions;v)simulating and modeling the dynamics of stellar streams and their progenitors;vi)modeling the motion of the Milky Way,M31 and other distant satellites under the framework of Local Group timing argument;and vii)measurements made by linking the brightest Galactic satellites to their counterparts in simulations.For each class of methods,we introduce their theoretical and observational background,the method itself,the sample of available tracer objects,model assumptions,uncertainties,limits and the corresponding measurements that have been achieved in the past.Both the measured total masses within the radial range probed by tracer objects and the extrapolated virial masses are discussed and quoted.We also discuss the role of modern numerical simulations in terms of helping to validate model assumptions,understanding systematic uncertainties and calibrating the measurements.While measurements in the last two decades show a factor of two scatters,recent measurements using Gaia DR2 data are approaching a higher precision.We end with a detailed discussion of future developments in the field,especially as the size and quality of the observational data will increase tremendously with current and future surveys.In such cases,the systematic uncertainties will be dominant and thus will necessitate a much more rigorous testing and characterization of the various mass determination methods.

Gravitational Field as a Pressure Force from Logarithmic Lagrangians and Non-Standard Hamiltonians：The Case of Stellar Halo of Milky Way

Recently,the notion of non-standard Lagrangians was discussed widely in literature in an attempt to explore the inverse variational problem of nonlinear differential equations.Different forms of non-standard Lagrangians were introduced in literature and have revealed nice mathematical and physical properties.One interesting form related to the inverse variational problem is the logarithmic Lagrangian,which has a number of motivating features related to the Li′enard-type and Emden nonlinear differential equations.Such types of Lagrangians lead to nonlinear dynamics based on non-standard Hamiltonians.In this communication,we show that some new dynamical properties are obtained in stellar dynamics if standard Lagrangians are replaced by Logarithmic Lagrangians and their corresponding non-standard Hamiltonians.One interesting consequence concerns the emergence of an extra pressure term,which is related to the gravitational field suggesting that gravitation may act as a pressure in a strong gravitational field.The case of the stellar halo of the Milky Way is considered.

The first comprehensive Milky Way stellar mock catalogue for the Chinese Space Station Telescope Survey Camera

The Chinese Space Station Telescope(CSST)is a cutting-edge two-meter astronomical space telescope currently under construction.Its primary Survey Camera(SC)is designed to conduct large-area imaging sky surveys using a sophisticated seven-band photometric system.The resulting data will provide unprecedented data for studying the structure and stellar populations of the Milky Way.To support the CSST development and scientific projects related to its survey data,we generate the first comprehensive Milky Way stellar mock catalogue for the CSST SC photometric system using the TRILEGAL stellar population synthesis tool.The catalogue includes approximately 12.6 billion stars,covering a wide range of stellar parameters,photometry,astrometry,and kinematics,with magnitude reaching down to g=27.5 mag in the AB magnitude system.The catalogue represents our benchmark understanding of the stellar populations in the Milky Way,enabling a direct comparison with the future CSST survey data.Particularly,it sheds light on faint stars hidden from current sky surveys.Our crowding limit analysis based on this catalogue provides compelling evidence for the extension of the CSST Optical Survey(OS)to cover low Galactic latitude regions.The strategic extension of the CSST-OS coverage,combined with this comprehensive mock catalogue,will enable transformative science with the CSST.