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The FAST all sky HI survey(FASHI):The first release of catalog

Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 112-133页

作者： Chuan-Peng Zhang Ming Zhu Peng Jiang Cheng Cheng Jing Wang Jie Wang Jin-Long Xu Xiao-Lan Liu Nai-Ping Yu Lei Qian Haiyang Yu Mei Ai Yingjie Jing Chen Xu Ziming Liu Xin Guan Chun Sun Qingliang Yang Menglin Huang Qiaoli Hao FAST Collaboration Guizhou Radio Astronomical Observatory Guizhou UniversityGuiyang 550000China National Astronomical Observatories Chinese Academy of Sciences(CAS)Beijing 100101China Chinese Academy of Sciences South America Center for Astronomy National Astronomical ObservatoriesCASBeijing 100101China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China

The FAST All Sky HI survey(FASHI)was designed to cover the entire sky observable by the Five-hundred-meter Aperture Spherical radio Telescope(FAST),spanning approximately 22000 square degrees of declination between-14°and+66°,and in the frequency range of 1050-1450 MHz,with the expectation of eventually detecting more than 100000 HI *** August 2020 and June 2023,FASHI had covered more than 7600 square degrees,which is approximately 35%of the total sky observable by *** has a median detection sensitivity of around 0.76 m Jy beam-1and a spectral line velocity resolution of~6.4 km s-1at a frequency of~1.4 *** of now,a total of 41741 extragalactic HI sources have been detected in the frequency range 1305.5-1419.5 MHz,corresponding to a redshift limit of z■*** cross-matching FASHI sources with the Siena Galaxy Atlas(SGA)and the Sloan Digital Sky Survey(SDSS)catalogs,we found that 16972(40.7%)sources have spectroscopic redshifts and 10975(26.3%)sources have only photometric *** of the remaining 13794(33.0%)HI sources are located in the direction of the Galactic plane,making their optical counterparts difficult to identify due to high extinction or high contamination of Galactic stellar *** on current survey results,the FASHI survey is an unprecedented blind extragalactic H I *** has higher spectral and spatial resolution and broader coverage than the Arecibo Legacy Fast ALFA Survey(ALFALFA).When completed,FASHI will provide the largest extragalactic HI catalog and an objective view of HI content and large-scale structure in the local universe.

关键词： surveys redshifts galaxies telescope radio lines HI line

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The galaxy luminosity function in the LAMOST Complete Spectroscopic Survey of Pointing Area at the Southern Galactic Cap

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Research in Astronomy and Astrophysics 2019年第8期19卷 69-80页

作者： Pin-Song Zhao Hong Wu Cong Kevin Xu Ming Yang Fan Yang Yi-Nan Zhu Man I Lam Jun-Jie Jin Hai-Long Yuan Hao-Tong Zhang Shi-Yin Shen Jian-Rong Shi A-Li Luo Xue-Bing Wu Yong-Heng Zhao Yi-Peng Jing Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing100049China Chinese Academy of Sciences South America Center for Astronomy China-Chile Joint Center for AstronomyCamino El Observatorio1515Las CondesSantiagoChile IAASARS National Observatory of AthensVas.Pavlou&I.MetaxaPenteli15236Greece Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy ofSciencesShanghai200030China Department of Astronomy School of PhysicsPeking UniversityBeijing100871China School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai200240China

We present optical luminosity functions(LFs) of galaxies in the0.1 g,0.1 r,0.1 i bands, calculated using data in40 deg2 sky area of the LAMOST Complete Spectroscopic Survey of Pointing Area(LaCoSSPAr) in the Southern Galactic Cap. redshifts for galaxies brighter than r = 18.1 were obtained mainly with LAMOST. In each band, LFs derived using both parametric and non-parametric maximum likelihood methods agree well with each other. In the0.1 r band, our fitting parameters of the Schechter function are φ*=(1.65 ± 0.36) × 10-2 h3 Mpc-3, M*=-20.69 ± 0.06 mag and α =-1.12 ± 0.08,which agree with previous studies. Separate LFs are also derived for emission line galaxies and absorption line galaxies. The LFs of absorption line galaxies show a dip at0.1 r 18.5 and can be fitted well by a double-Gaussian function, suggesting a bimodality in passive galaxies.

关键词： galaxies:luminosity function,mass function galaxies:statistics galaxies:distances and redshifts

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An efficient method to identify galaxy clusters by using SuperCOSMOS,2MASS and WISE data

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Science China(Physics,Mechanics & Astronomy) 2014年第11期57卷 2168-2173页

作者： XU WeiWei WEN ZhongLue HAN JinLin National Astronomical Observatories Chinese Academy of Sciences University of Chinese Academy of Sciences

The survey data of Wide-field Infrared Survey Explorer(WISE)provide an opportunity for the identification of galaxy *** present an efficient method for detecting galaxy clusters by combining the WISE data with SuperCOSMOS and 2MASS *** performing star-galaxy separation,we calculate the number of companion galaxies around the galaxies with photometric redshifts previously estimated by the SuperCOSMOS,2MASS and WISE data.A scaled richness Rscal 30 is set as a criterion to identify *** a sky area of 275 deg2of the Sloan Digital Sky Survey Stripe 82 region,we identify 302 clusters in the redshift range of 0.1

关键词： infrared galaxy clusters redshifts

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The Photometric Maximum in Cosmicflows-2

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Journal of High Energy Physics, Gravitation and Cosmology 2018年第1期4卷 123-131页

作者： Lorenzo Zaninetti Physics Department via P. Giuria 1 Turin Italy

Based on well known photometric rules for the number of galaxies as function of the distance in Mpc we model the so called “Great Wall” which is visible on the Cosmicflows-2 catalog. The gravitational field is evalu... 详细信息

关键词： Cosmology Observational Cosmology Distances redshifts Radial Velocities Spatial Distribution of Galaxies Magnitudes and Colors Luminosities

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Doppler Boosting May Have Played No Significant Role in the Finding Surveys of Radio-Loud Quasars

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International Journal of Astronomy and Astrophysics 2012年第1期2卷 52-61页

作者： Morley B. Bell Herzberg Institute of Astrophysics National Research Council Ottawa Canada

There appears to be a fundamental problem facing Active Galactic Nuclei (AGN) jet models that require highly relativistic ejection speeds and small jet viewing angles to explain the large apparent superluminal motions seen in so many of the radio-loud quasars with high redshift. When the data are looked at closely it is found that, assuming the core component is unboosted, only a small percentage of the observed radio frequency flux density from these sources can be Doppler boosted. If the core component is boosted the percentage of boosted to unboosted flux will be higher but will still be far from the 90 percent required for Doppler boosting to have played a significant role. Without a highly directed, Doppler boosted component that dominates the observed flux, radio sources found in low-frequency finding surveys cannot be preferentially selected with small jet viewing angles. The distribution of jet orientations will then follow the sini curve associated with a random distribution, where only a very few sources (~1%) will have the small viewing angles ( 10c, and this makes it difficult to explain how around 33% of the radio-loud AGNs with high redshift can exhibit such highly superluminal motions. When the boosted component is the dominant one it can be argued that in a flux limited sample only those members with small viewing angles would be picked up while those with larger viewing angles (the un-boosted ones) would be missed. However, this is not the case when the boosted component is small and a new model to explain the high apparent superluminal motions may be needed if the redshifts of high-redshift quasars are to remain entirely cosmological.

关键词： Galaxies Distances and redshifts Galaxies Quasars General

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On Five Independent Phenomena Sharing a Common Cause

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Journal of Applied Mathematics and Physics 2014年第5期2卷 39-49页

作者： Roger Ellman The-Origin Foundation Inc. Santa Rosa CA USA

Over the past century a succession of four different independent unexplained astronomical phenomena have been discovered. They appear to be the result of a common underlying cause that also produces an unaccounted—for acceleration that is quite small, centrally directed in the system exhibiting each phenomenon, non-gravitational, distance independent, and of a common magnitude. The present paper analyzes the unexplained phenomena and proposes the underlying common cause, a common solution to the problem that they present. The four in the order of their discovery are as follows. 1) In 1933, the indication by galactic rotation curves that there is such an acceleration in galaxies but with no observable cause [hence the postulating of “Dark Matter”]. Here the acceleration is directed toward the galactic center, the dominant factor in the mechanics of galaxy rotation. 2) In 1998, the Pioneer Anomaly in which the acceleration is directed toward the Sun, the dominant factor in the mechanics of the Pioneer spacecrafts’ motion. 3) In 2008, the Flybys Anomaly for which the acceleration is directed toward the center of the Earth, the dominant factor in the mechanics of the flyby motion. 4) Also in 2008, confirmed in 2010, the Dark Flow anomaly for which the acceleration is directed toward the central origin of the overall universe, the dominant factor in the mechanics of the overall universe. In addition the common cause also modifies the earliest: 5) In the 1920’s the LeMaitre-Hubble redshifts of the light from various distant astral bodies.

关键词： Dark Matter Pioneer Anomaly Flybys Anomaly Dark Flow Anomaly redshifts

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A Possible Alternative to the Accelerating Universe IV

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Journal of Modern Physics 2017年第4期8卷 622-635页

作者： Frank R. Tangherlini P.O. Box 928211 San Diego CA 92192 USA

This work briefly reviews and extends the author’s three previous works (2015), Journal of Modern Physics, 6, 78-87, and 1360-1370;(2016), 7, 1829-1844 that propose as an alternative to the accelerating ΛCDM universe, the decelerating Einstein de Sitter (EdS) universe, in which dark energy is a different phase of dark matter located only in intergalactic space (IGS), and that instead of a negative pressure, it has an index of refraction n≈1.50, and hence a reduced speed of light c / n through it. This allows the EdS universe to expand the extra distance necessary to obtain the diminished brightness of the Type Ia supernovae. In view of the recent suggestion that the universe is not accelerating, but possibly expanding uniformly, a table is given comparing both the accelerating and uniformly expanding universes with the EdS universe supplemented by the reduced speed of light. It is shown that fitting the uniformly expanding universe leads to a smaller value of n, and hence too short an age for the EdS universe, unlike the case with fitting the accelerating universe. The main result is that the proposed reduced speed of light in the IGS predicts discordant redshifts. It is shown that the current explanation of “accidental superposition,” is most likely insufficient to explain the number of observations, and that the present proposal could make up the difference. It can be tested astronomically, as illustrated in a figure.

关键词： Dark Energy Speed of Light Expansion Comparisons Discordant redshifts

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An Analytical Solution in the Complex Plane for the Luminosity Distance in Flat Cosmology

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Journal of High Energy Physics, Gravitation and Cosmology 2016年第4期2卷 581-586页

作者： Lorenzo Zaninetti Physics Department Via P. Giuria 1 Turin Italy

We present an analytical solution for the luminosity distance in spatially flat cosmology with pressureless matter and the cosmological constant. The complex analytical solution is made of a real part and a negligible imaginary part. The real part of the luminosity distance allows finding the two parameters H0 and ΩM . A simple expression for the distance modulus for SNs of type Ia is reported in the framework of the mini-max approximation.

关键词： Cosmology Observational Cosmology Distances redshifts Radial Velocities Spatial Distribution of Galaxies

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Galaxies “Boiling off” Electrons Due to the Photo-Electric Effect Leading to a New Model of the IGM and a Possible Mechanism for “Dark Matter”

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Journal of High Energy Physics, Gravitation and Cosmology 2019年第1期5卷 181-192页

作者： Lyndon Ashmore Independent Researcher Southend UK

The Intergalactic Medium (IGM) is commonly thought to be occupied by approximately one atom of Hydrogen per cubic metre of space either as neutral Hydrogen or partially/fully ionised. This cannot be true as galaxies will “boil off” electrons from their outer surfaces by the photo-electric effect and so the IGM must be filled with electrons. UV and X-ray photons, as they leave the galaxy, can remove an electron from a Hydrogen atom at the surface of the galaxy, give it sufficient energy to escape the gravitational pull of the galaxy and go on to fill the IGM. A typical galaxy emits approximately 5×1047 X-ray photons each second. All of which pass through the outer surface of the galaxy and have sufficient energy to eject an electron and send it off to the IGM. Adding to these photons in the UV and gamma, we can see that galaxies are ejecting large amounts of electrons each second that go on to fill the IGM. Data from FRB 121102 give the value for the electron number density in the IGM as ne ≈ 0.5 m-3. Under certain conditions, an electron gas will crystallise into a Wigner-Seitz crystal. Here the electrical potential energy of repulsion between the electrons dominates their kinetic energy and the electrons form on a BCC lattice structure. The electrons oscillate, performing SHM about their lattice positions. With ne ≈ 0.5 m-3 the electrons in the IGM satisfy the energy criteria for crystallisation to occur when interacting with other electrons within a sphere far less in radius than the corresponding Debye sphere. Thus, the conditions are met for the electrons to form an “electron glass.” Since the electrons in their BCC formation are spatially coherent, light will travel through the crystals in a straight line and thus objections to “Tired Light” theories are now removed since images will neither be destroyed nor “blurred.” Charges are not created but separated, if the electrons are removed from the galaxy and sent to fill the IGM;the remaining protons are left behi

关键词： Intergalactic Medium IGM Galaxies Dark Matter redshifts CMBR Tired Light Wigner Crystals

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Sparse Formulae for the Distance Modulus in Cosmology

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Journal of High Energy Physics, Gravitation and Cosmology 2021年第3期7卷 965-992页

作者： Lorenzo Zaninetti Physics Department Turin Italy

We review the distance modulus in twelve different cosmologies: the ΛCDM model, the wCDM model, the Cardassian model, the flat case, the øCDM cosmology, the Einstein—De Sitter model, the modified Einstein—De Sitter model, the simple GR model, the flat expanding model, the Milne model, the plasma model and the modified tired light model. The above distance moduli are processed for three different compilations of supernovae and a supernovae + GRBs compilation: Union 2.1, JLA, the Pantheon and Union 2.1 + 59 GRBs. For each of the 48 analysed cases we report the relative cosmological parameters, the chi-square, the reduced chi-square, the AIC and the Q parameter. The angular distance as function of the redshift for five cosmologies is reported in the framework of the minimax approximation.

关键词： Cosmology Observational Cosmology Distances redshifts Radial Velocities Spatial Distribution of Galaxies Magnitudes and Colours Luminosities

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