The unified generalized non-local theory is applied for mathematical modeling of cosmic objects. For the case of galaxies the theory leads to the flat rotation curves known from observations. The transformation of Kep...The unified generalized non-local theory is applied for mathematical modeling of cosmic objects. For the case of galaxies the theory leads to the flat rotation curves known from observations. The transformation of Kepler’s regime into the flat rotation curves for different solitons is shown. The Hubble expansion with acceleration is explained as result of mathematical modeling based on the principles of non-local physics. Peculiar features of the rotational speeds of galaxies and effects of the Hubble expansion need not in the introduction of new essence like dark matter and dark energy. The origin of difficulties consists in the total Oversimplification following from the principles of local physics.展开更多
We report two new sets of tidal debris nearby the Sagittarius （Sgr） tidal stream in the north Galactic cap （NGC） identified from the M giant stars in LAMOST DR2. The M giant stars located in the sky area of 210...We report two new sets of tidal debris nearby the Sagittarius （Sgr） tidal stream in the north Galactic cap （NGC） identified from the M giant stars in LAMOST DR2. The M giant stars located in the sky area of 210° 〈 A 〈 290°, and having a distance of 10-20 kpc and We/HI 〈 -0.75 show clear bimodality in their velocity distribution. We denote the two peaks as Vel-3＋83 for the one within a mean velocity of -3 km s^-1 with respect to that of the well observed Sgr leading tail at the same A and Ve1＋162＋26 for the other one with a mean velocity of 162km s^-1 with respect to the Sgr leading tail. Although the projected A-Vgsr relation of Vel-3＋83 is very similar to the Sgr leading tail, the opposite trend in the A-distance relation as compared to the Sgr leading tail suggests Vel-3＋83 has a different 3D direction of motion with any branch of the simulated Sgr tidal stream from Law ＆ Majewski. Therefore, we propose it is new tidal debris not related to the Sgr stream. Similarly, the other substructure Vel＋162＋26, which is the same one as the NGC group discovered by Chou et al., also moves toward a different direction with respect to the Sgr stream, implying that it may have a different origin than the Sgr tidal stream.展开更多
The abundances of long-lived radioactive elements Th and U observed in metal-poor halo stars can be used as chronometers to determine the age of individual stars, and hence set a lower limit on the age of the Galaxy a...The abundances of long-lived radioactive elements Th and U observed in metal-poor halo stars can be used as chronometers to determine the age of individual stars, and hence set a lower limit on the age of the Galaxy and hence of the universe. This radioactive dating requires the zero-decay productions of Th and U, which involves complicated r-process nucleosynthesis calculations. Several parametric r-process models have been used to calculate the initial abundance ratios of Th/Eu and U/Th, but, due to the sharp sensitivity of these models to nuclear physics inputs, the calculations have relatively large uncertainties which lead to large uncertainties in the age determinations. In order to reduce these uncertainties, we present a simple method to estimate the initial productions of Th and U, which only depends on the solar system abundances and the stellar abundances of stable r-process elements. From our calculations of the initial abundance ratios of Th/Eu and U/Th, we re-estimate the ages of those very metal-poor halo stars with published abundances of Th and U. Our age estimates are consistent, within the errors, with the other age determinations derived from r-process models, and offer useful constrains for r-process theoretical calculations. The advantages and limitations of our simple method of radioactive dating are discussed.展开更多
We used the star counts in 21 BATC fields obtained with the National Astronomical Observatories （NAOC） 60/90 cm Schmidt Telescope to study the structure of the Galactic halo. Adopting a de Vaucouleurs r1/4 law halo,...We used the star counts in 21 BATC fields obtained with the National Astronomical Observatories （NAOC） 60/90 cm Schmidt Telescope to study the structure of the Galactic halo. Adopting a de Vaucouleurs r1/4 law halo, we found that the halo is somewhat flatter （c/a - 0.4） towards the Galactic center than in the anticentre and antirotation direction （c/a 〉 0.4）. We also notice that the axial ratios are smaller （flatter） towards the low latitude fields than the high latitude fields, except for a few fields. We provide robust limits on the large-scale flattening of the halo. Our analysis shows that the axial ratio of the halo may vary with distance and the observation direction. At large Galactocentric radii, the halo may not have a smooth density distribution, but rather, it may be largely composed of overlapping streams or substructures, which provides a support for the hybrid formation model.展开更多
文摘The unified generalized non-local theory is applied for mathematical modeling of cosmic objects. For the case of galaxies the theory leads to the flat rotation curves known from observations. The transformation of Kepler’s regime into the flat rotation curves for different solitons is shown. The Hubble expansion with acceleration is explained as result of mathematical modeling based on the principles of non-local physics. Peculiar features of the rotational speeds of galaxies and effects of the Hubble expansion need not in the introduction of new essence like dark matter and dark energy. The origin of difficulties consists in the total Oversimplification following from the principles of local physics.
基金supported by the Strategic Priority Research Program “The Emergence of Cosmological Structures” of the Chinese Academy of Sciences(Grant No.XDB09000000)the National Key Basic Research Program of China(2014CB845700)+2 种基金the National Natural Science Foundation of China(NSFC,Grant Nos.11373032,11333003and U1231119)the NSFC(Grant Nos.11173044 and 11503066)the Shanghai Natural Science Foundation(14ZR1446900)
文摘We report two new sets of tidal debris nearby the Sagittarius （Sgr） tidal stream in the north Galactic cap （NGC） identified from the M giant stars in LAMOST DR2. The M giant stars located in the sky area of 210° 〈 A 〈 290°, and having a distance of 10-20 kpc and We/HI 〈 -0.75 show clear bimodality in their velocity distribution. We denote the two peaks as Vel-3＋83 for the one within a mean velocity of -3 km s^-1 with respect to that of the well observed Sgr leading tail at the same A and Ve1＋162＋26 for the other one with a mean velocity of 162km s^-1 with respect to the Sgr leading tail. Although the projected A-Vgsr relation of Vel-3＋83 is very similar to the Sgr leading tail, the opposite trend in the A-distance relation as compared to the Sgr leading tail suggests Vel-3＋83 has a different 3D direction of motion with any branch of the simulated Sgr tidal stream from Law ＆ Majewski. Therefore, we propose it is new tidal debris not related to the Sgr stream. Similarly, the other substructure Vel＋162＋26, which is the same one as the NGC group discovered by Chou et al., also moves toward a different direction with respect to the Sgr stream, implying that it may have a different origin than the Sgr tidal stream.
基金Supported by the National Natural Science Foundation of China.
文摘The abundances of long-lived radioactive elements Th and U observed in metal-poor halo stars can be used as chronometers to determine the age of individual stars, and hence set a lower limit on the age of the Galaxy and hence of the universe. This radioactive dating requires the zero-decay productions of Th and U, which involves complicated r-process nucleosynthesis calculations. Several parametric r-process models have been used to calculate the initial abundance ratios of Th/Eu and U/Th, but, due to the sharp sensitivity of these models to nuclear physics inputs, the calculations have relatively large uncertainties which lead to large uncertainties in the age determinations. In order to reduce these uncertainties, we present a simple method to estimate the initial productions of Th and U, which only depends on the solar system abundances and the stellar abundances of stable r-process elements. From our calculations of the initial abundance ratios of Th/Eu and U/Th, we re-estimate the ages of those very metal-poor halo stars with published abundances of Th and U. Our age estimates are consistent, within the errors, with the other age determinations derived from r-process models, and offer useful constrains for r-process theoretical calculations. The advantages and limitations of our simple method of radioactive dating are discussed.
基金the National Natural Science Foundation of China
文摘We used the star counts in 21 BATC fields obtained with the National Astronomical Observatories （NAOC） 60/90 cm Schmidt Telescope to study the structure of the Galactic halo. Adopting a de Vaucouleurs r1/4 law halo, we found that the halo is somewhat flatter （c/a - 0.4） towards the Galactic center than in the anticentre and antirotation direction （c/a 〉 0.4）. We also notice that the axial ratios are smaller （flatter） towards the low latitude fields than the high latitude fields, except for a few fields. We provide robust limits on the large-scale flattening of the halo. Our analysis shows that the axial ratio of the halo may vary with distance and the observation direction. At large Galactocentric radii, the halo may not have a smooth density distribution, but rather, it may be largely composed of overlapping streams or substructures, which provides a support for the hybrid formation model.
