Group Velocity of the Density Waves in Galactic Disks

This letter is emphasized on the discussion of the group velocity of disturbed galactic density waves(GDW),which is one of the two most insurmountable problems in the density waves theory.In our calculation,we find that the galactic thickness has an important effect on the GDW.The dynamic time scale of GDW in our three-dimensional model can be prominently prolonged,from 36%to 60%contrasting to that of two-dimensional galactic model.However,it is still less than the lifetime of our Galaxy,which means that it is necessary to seek some other physical mechanisms to excite and sustain the GDW.

The lack of carbon stars in the Galactic bulge

In order to explain the lack of carbon stars in the Galactic bulge, we have made a detailed study of thermal pulseasymptotic giant branch （TP-AGB） stars by using a population synthesis code. The effects of the oxygen overabundance and the mass loss rate on the ratio of the number of carbon stars to that of oxygen stars in the Galactic bulge are discussed. We find that the oxygen overabundance which is about twice as large as that in the solar neighbourhood （close to the present observations） is insufficient to explain the rareness of carbon stars in the bulge. We suggest that the large mass loss rate may serve as a controlling factor in the ratio of the number of carbon stars to that of oxygen stars.

Simulation of the Galactic Cosmic Ray Shadow of the Sun

The cosmic-ray particles of TeV-regime, outside the solar system are blocked in their way to the Earth, a deficit of particles is observed corresponding to the location of the Sun known as the Sun shadow. The center of the Sun shadow is shifted from its nominal position due to the presence of magnetic fields in interplanetary space,and this shift is used indirectly as a probe to study the solar magnetic field that is difficult to measure otherwise.A detailed Monte Carlo simulation of galactic cosmic-ray propagation in the Earth-Sun system is carried out to disentangle the cumulative effects of solar, interplanetary and geomagnetic fields. The shadowing effects and the displacements results of the Sun shadow in different solar activities are reproduced and discussed.

ERRATUM:"Statistics of the Galactic Supernova Remnants"(ChJAA, 5(2), 165 [2005])

We thank Dr. Dave Green (MRAO, UK) for one comment and one identified problem in our paper. The comment is that we did not discuss selection effects of the current sample of supernova remnants, which can be found in Case & Bhattacharya (1998) and Green (2004).

Galactic Kinematics Derived From Hipparcos Proper Motions

Analyzing Hipparcos proper motions of 1352 O B5 stars, we have found a clear stellar warping motion that is a systematic rotation +3 8±1 1 kms -1 kpc -1 of stars about the axis pointing to the galactic center in the sense of increasing the inclination of the HI warp, and a remarkably large galactic rotation of (V 0) O-B5 = 268 7 ± 11 9kms -1 , compared with the IAU recommendation (V 0 = 220 ± 20kms -1 ), given the galactocentric distance of the sun R 0 = 8 5kpc. Combining Hipparcos proper motions and the radial velocity data, we have then studied the kinematics for 151 classical cepheids. The results show a contracting motion of the Galaxy in the solar neibourhood, V θ/θ/R =-2 60 ± 1 07kms -1 kps -1 , which is along the solar circle. In the present paper, we have also analyzed proper motions of 21000 K-M giants, and again we found a large galactic rotation (V 0) K-M = 252 6±9 5kms -1 .

Investigation of Galactic open cluster remnants： the case of NGC 7193

Galactic open clusters （OCs） that survive the early gas-expulsion phase are gradually de- stroyed over time by the action of disruptive dynamical processes. Their final evolutionary stages are characterized by a poorly populated concentration of stars called an open cluster remnant （OCR）. This study is devoted to assessing the real physical nature of the OCR candidate NGC 7193. GMOS/Gemini spectroscopy of 53 stars in the inner target region were obtained to derive radial velocities and at- mospheric parameters. We also employed photometric and proper motion data. The analysis method consists of the following steps： （i） analysis of the statistical resemblance between the cluster and a set of field samples with respect to the sequences defined in color-magnitude diagrams （CMDs）; （ii） a 5-dimensional iterative exclusion routine was employed to identify outliers from kinematical and posi- tional data; （iii） isochrone fitting to thes× （J - Ks） CMD of the remaining stars and the dispersion of spectral types along empirical sequences in the （J - H） × （H - Ks） diagram were checked. A group of stars was identified for which the mean heliocentric distance is compatible with that obtained via isochrone fitting and whose metallicities are compatible with each other. Fifteen of the member stars observed spectroscopically were identified together with another 19 probable members. Our results indi- cate that NGC 7193 is a genuine OCR, of a once very populous OC, for which the following parameters were derived： d = 501±46 pc, t = 2.5±1.2 Gyr, （[Fe/H]） = -0.17±0.23 and E（B-V） = 0.05±0.05. Its luminosity and mass functions show depletion of low mass stars, confirming the OCR is in a dynam- ically evolved state.

Ionization of protoplanetary disks by galactic cosmic rays,solar protons,and supernova remnants

Galactic cosmic rays and solar protons ionize the present terrestrial atmosphere,and the air showers are simulated by well-tested Monte-Carlo simulations,such as PHITS code.We use the latest version of PHITS to evaluate the possible ionization of protoplanetary disks by galactic cosmic rays（GCRs）,solar protons,and by supernova remnants.The attenuation length of GCR ionization is updated as 118 g cm^-2,which is approximately 20% larger than the popular value.Hard and soft possible spectra of solar protons give comparable and 20% smaller attenuation lengths compared with those from standard GCR spectra,respectively,while the attenuation length is approximately 10% larger for supernova remnants.Further,all of the attenuation lengths become 10% larger in the compound gas of cosmic abundance,e.g.128 g cm^-2 for GCRs,which can affect the minimum estimate of the size of dead zones in protoplanetary disks when the incident flux is unusually high.

Influence of Supernova SN Ia Rate and the Early Star Formation Rate on the Galactic Chemical Evolution

Based on the recently developed numerical approach to understand the formation and the chemical evolution of the milky-way galaxy in the solar neighborhood we study the influence of the supernova type SN Ia rates on the galactic chemical evolution. Supernova SN Ia plays an important role in producing the iron inventory of the galaxy. We also study the dependence of the chemical evolution on the star formation rate prevailing during the initial one billion years of the evolution of the galaxy. This era marks the formation of the galactic halo and the thick disk. A comparison of the elemental abundance distributions of the dwarf stars in the solar neighborhood is made among the various models simulated in the present work. In order to explain the majority of the observed elemental evolutionary trends, specifically those related with the galactic evolution of iron and oxygen, it would be essential to incorporate a major component of prompt SN Ia to the galactic evolution. The prompt SN Ia would produce significant fraction of SN Ia within the initial ~100 million years from the time of star formation. The essential requirement of prompt SN Ia would result in a significant enhancement of SN Ia rates during the earliest epoch of the galaxy. The elemental evolutionary trends also favor an enhancement in the star formation rate during the initial one billion years of the galaxy at least by a factor of three compared to the trend prevailing during the latter evolutionary time of the galaxy.

Revisiting Galactic Rotation Curves Given a Noncommutative-Geometry Background

It was shown earlier by Rahaman et al. that a noncommutative-geometry background can account for galactic rotation curves without the need for dark matter. The smearing effect that characterizes noncommutative geometry is described by means of a Gaussian distribution intended to replace the Dirac delta function. The purpose of this paper is two-fold: 1) to account for the galactic rotation curves in a more transparent and intuitively more appealing way by replacing the Gaussian function by the simpler Lorentzian distribution proposed by Nozari and Mehdipour and 2) to show that the smearing effect is both a necessary and sufficient condition for meeting the stability criterion.

Distribution of SiO and OH Maser Stars in the Galactic Plane

The observational results of the Nobeyama 45-m SiO maser survey and the Arecibo 305-m OH maser survey are assembled for an analysis of the distribution and kinematics of late-type stars in the Galactic plane. It is found that neither SiO maser stars nor OH maser stars show any concentration to the spiral arms, which imply that they do not belong to the arm population and quite possibly they are low-mass stars in late stage of evolution. A rotational curve is also derived for these objects and a few features which may be real are discussed and compared with those derived from planetary nebulae and AGB stars.

Galactic Route to the Strong Coupling Constant αs(mz) and Its Implication on the Mass Constituents of the Universe

Some fundamental physical quantities need an alternative description. We derive the word average value of interaction coupling constant αs(mz) from the observed maximum galactic rotation velocity by the simple relation , where is the velocity, at which the difference between galactic rotation velocity and Thomas precession is equal, and α is Sommerfeld’s constant. The result is in excellent agreement with the value of αs = 0.1170 ± 0.0019, recently measured and verified via QCE analysis by CERN researchers. One can formulate a reciprocity relation, connecting αs with the circle constant: . It is the merit of Preston Guynn to derive the Milky Way maximum value of the galactic rotation velocity βg, pointing to its “extremely important role in all physics”. The mass (energy) constituents of the Universe follow a golden mean hierarchy and can simply be related to the maximum of Guynn’s difference velocity respectively to αs(mz), therewith excellently confirming Bouchet’s WMAP data analysis. We conclude once more that the golden mean concept is the leading one of nature.

Galactic Haloes from Self-Interacting Neutrinos

The objective of this research is to provide an explanation of galactic haloes using established particles and forces using recent theoretical developments. Light fermions, with masses on the order of 1 eV/c2, are not a leading candidate for dark matter because of their large free-streaming scale length and their violation of the Tremaine-Gunn bound. With a self-interaction of fermions, the free-streaming scaling length is reduced, and the tenets of the Tremaine-Gunn bound are not applicable. Binding of neutrinos via a feeble SU(3) force is considered as a model for such interactions. The assumed sum of masses of the three neutrino flavors is 0.07 eV/c2. The resulting form of matter for such bound neutrinos is found to be a degenerate Fermi fluid. Pressure-equilibrium approaches applied to this fluid provide cuspy solutions and match observationally-inferred profiles for galactic haloes. Such approaches also match the observed total enclosed mass for galaxies similar to the Milky Way. The computed structures are found to be stable. The hypothesis is considered in view of observationally-inferred halo-halo interactions and gives results that are consistent with the observed Bullet cluster halo interaction. The theory gives agreement with observationally-inferred properties of dark matter near earth. Questions related to interaction rates, consistency with SN1987a data, the cosmic microwave background, the issue of SU(3) interactions between neutrinos and quarks, free-streaming after neutrino decoupling, and dark-matter abundance are addressed in a companion paper.

Galactic Structure and Holography

Galactic structure, involving bulk motion of matter conserving mass and angular momentum, is analyzed in a holographic large scale structure model. In isolated galaxies, baryonic matter inhabits dark matter halos with holographic radii determined by total galactic mass. The existence of bulgeless giant spiral galaxies challenges previous models of galaxy formation. In sharp contrast, holographic analysis is consistent with the finding that 15% of a sample of 15,000 edge-on disk galaxies in the sixth SDSS data release are bulgeless. Holographic analysis also indicates that E7 ellipticals are less than 2% of elliptical galaxies.

The Absolute Proper Motion of M3 and Its Galactic Orbit

We have obtained the absolute proper motion of globular cluster M3 from measurements of 14 plates taken with the 40cm refractor at Sheshan station of Shanghai observatory, spanning epoch is about 80 years. The positions and absolute proper motions of 24 stars in ACT catalogue are used as the reference frame. The reduction was made with the central overlapping principle. The absolute proper motions of 534 stars in the region of about 1° 5×1° 5 around the cluster M3 are determined. With the new data of proper motions, the membership probabilities of the stars are determined. The mean absolute proper motions for the cluster of -0 3±0 3 mas/yr in R.A. and -3 1±0 3 mas/yr in Dec. were obtained.Combining our results with the known distance and radial velocity of the cluster, we obtained its space motions and Galactic orbits in two different three component Galactic potentials.

Mechanics of the Gyroscopic Precession and Calculation of the Galactic Mass

A spinning gyroscope precesses about the vertical due to a torque acting upon the wheel. The torque is generated by the shift of moment of force by gravity and it points to the vertical instead of the tangential direction of precession. This intuition offers an alternative and straightforward view of precession dynamics in comparison with the literature. It also presumes a dynamic balance of momentum between circular motions of the wheel spin and precession. Accordingly, the gyroscopic dynamics is then applied to the study of galactic motion of the solar system in space and the Galactic mass is calculated with the inclusion of gyroscopic effect of the solar planets. Results indicate that the gyroscopic effect of Mercury orbiting around the Sun can increase the calculated Galactic mass by 23% in comparison with the result obtained by the classic approach.

Constraints on axion-like particles from the observation of Galactic sources by the LHAASO

High-energy photons may oscillate with axion-like particles(ALPs)when they propagate through the Milky Way's magnetic field,resulting in an alteration in the observed photon energy spectrum.Ultra-high energy gamma-ray spectra,measured by the Large High Altitude Air Shower Observatory(LHAASO)up to O(1)PeV,provide a promising opportunity to investigate the ALP-photon oscillation effect.In this study,we utilize the gamma-ray spectra of four Galactic sources measured by the LHAASO,that is,the Crab Nebula,LHAASO J2226+6057,LHAASO J1908+0621,and LHAASO J1825-1326,to explore this effect.We employ the CLsmethod to set constraints on the ALP parameters.Our analysis of the observations of the four sources reveals that the ALPphoton coupling gaγis constrained to be smaller than 1.4×10^(-1)0GeV^(-1)for an ALP mass of~4×10^(-7)eV at 95%C.L.Combining the observations of the Crab Nebula from the LHAASO and other experiments,we find that the ALP-photon coupling may be set to approximately 7.5×10^(-11)GeV^(-1)for an ALP mass of~4×10^(-7)eV,which is similar to the CAST constraint.

Explanation of Two Important Empirical Relations for Galaxies

The phenomenon of “missing mass” in galaxies has triggered new theoretical exploration, forming a competition between dark matter assumption, modified Newtonian dynamics and modified gravity. Over the past forty years, various versions of the modified scenario have been proposed to simulate the effects of missing mass. These schemes replace the dynamic effect of dark matter by introducing some tiny extra force terms in the dynamic equations. Such extra forces have mainly interactions on large scales of galaxies, such as fitting the Tully-Fisher relation or asymptotically flat rotation curves. The discussion in this paper shows that the evidence of taking the modified schemes as fundamental theory is still insufficient. In this paper, we display a system of simplified galactic dynamical equations derived from weak field and low-speed approximations of Einstein field equations, and then we use it to discuss two important empirical relations in galactic dynamics, namely the Faber-Jackson relation and Tully-Fisher relation, as well as the related fundamental plane. These discussions provide a reference scheme for improving the dispersion of the empirical relations, and also provide a theoretical foundation to analyze the properties of dark matter and galactic structures.

The Unified Field

This is a Unified Field description based on the holographic Time Dilation Cosmology, TDC, model, which is an eternal continuum evolving forward in the forward direction of time, at the speed of light, c, at an invariant 1 s/s rate of time. This is the Fundamental Direction of Evolution, FDE. There is also an evolution down time dilation gradients, the Gravitational Direction of Evolution, GDE. These evolutions are gravity, which is the evolutionary force in time. Gravitational velocities are compensation for the difference in the rate of time, dRt, in a dilation field, and the dRtis equal to the compensatory velocity’s percentage of c, and is a measure of the force in time inducing the velocity. In applied force induced velocities, the dRt is a measure of the resistance in time to the induced velocity, which might be called “anti-gravity” or “negative gravity”. The two effects keep the continuum uniformly evolving forward at c. It is demonstrated that gravity is already a part of the electromagnetic field equations in way of the dRt element contained in the TDC velocity formula. Einstein’s energy formula is defined as a velocity formula and a modified version is used for charged elementary particle solutions. A time dilation-based derivation of the Lorentz force ties gravity directly to the electromagnetic field proving the unified field of gravity and the EMF. It is noted how we could possibly create gravity drives. This is followed by a discussion of black holes, proving supermassive objects, like massive black hole singularities, are impossible, and that black holes are massless Magnetospheric Eternally Collapsing Objects (MECOs) that are vortices in spacetime. .

An ACE/CRIS-observation-based Galactic Cosmic Rays heavy nuclei spectra model Ⅱ

An observation-based Galactic Cosmic Ray(GCR)spectral model for heavy nuclei is developed.Zhao and Qin[J.Geophys.Res.Space Phys.118,1837(2013)]proposed an empirical elemental GCR spectra model for nuclear charge 5≤z≤28 over the energy range^30 to 500 Me V/nuc,which is proved to be successful in predicting yearly averaged GCR heavy nuclei spectra.Based on the latest highly statistically precise measurements from ACE/CRIS,a further elemental GCR model with monthly averaged spectra is presented.The model can reproduce the past and predict the future GCR intensity monthly by correlating model parameters with the continuous sunspot number(SSN)record.The effects of solar activity on GCR modulation are considered separately for odd and even solar cycles.Compared with other comprehensive GCR models,our modeling results are satisfyingly consistent with the GCR spectral measurements from ACE/SIS and IMP-8,and have comparable prediction accuracy as the Badhwar&O’Neill 2014 model.A detailed error analysis is also provided.Finally,the GCR carbon and iron nuclei fluxes for the subsequent two solar cycles(SC 25 and 26)are predicted and they show a potential trend in reduced flux amplitude,which is suspected to be relevant to possible weak solar cycles.

A POSSIBLE MECHANISM FOR THE PRECESSION OF EXTRAGALACTIC JETS

Many jets ejected from active galactic nuclei show an inversion symmetry in shape, like the letter S, indicating that the jet is precessing about an axis. If the jet is ejected along the spin axis of the black hole in the galactic nucleus as generally accepted, then it is the