达勒姆和SDSS星表中的微弱星系数

IF 3.2 Q2 ASTRONOMY & ASTROPHYSICS
Galaxies Pub Date : 2023-05-07 DOI:10.3390/galaxies11030065
J. Marr
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引用次数: 0

摘要

达勒姆星系外天文学和宇宙学目录中的K-、H-、I-、R-、B-和U-波段的星系数量计数可以使用亮区SDSS得出的光度函数(LF)参数在其整个范围内很好地拟合,并且只需要随着LF斜率(α)的变陡而适度的光度演化,除了B波段的突然急剧增加和U波段在微弱星等下的不那么急剧的增加,这需要星暴进化模型来解释过量的微弱数量。在不需要暗物质或暗能量的情况下,将哈勃膨胀视为爱因斯坦曲率的宇宙学模型在微弱幅度下需要比标准∧CDM模型更少的校正。SDSS DR17在g、i、r、u和z波段的数据被用于构建红移≤0.4和mag≤20范围内的明亮星系数计数和星系红移/密度图,这两个区域分别位于北星系帽(NGC)和南星系帽(SGC)上方,面积分别为5954和859平方度,星系总数为622121个。它们的相对密度证实了南方天空中有一个大范围的空洞,红移z≤0.15时有26%的亏空。尽管由于其在较暗星等上的不完整性而未被包括在数量计数数据集中,但将SDSS红移数量计数调查扩展到红移≤1.20的较暗和更远的星系,显示了数量计数的第二个峰值,其中有许多QSO、明亮的X射线和无线电源,以及快速恒星形成率的进化中的不规则星系。这种红移0.45–0.65的亚群体可能是B波段观察到的过量计数的原因。HST和詹姆斯·韦伯太空望远镜(JWST)最近的观测也开始揭示高密度的高红移(z>7)大质量星系,具有高紫外线和X射线发射,JWST未来的观测可能揭示早期宇宙中星系的聚集可以追溯到宇宙中的第一束光。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Faint Galaxy Number Counts in the Durham and SDSS Catalogues
Galaxy number counts in the K-, H-, I-, R-, B- and U-bands from the Durham Extragalactic Astronomy and Cosmology catalogue could be well-fitted over their whole range using luminosity function (LF) parameters derived from the SDSS at the bright region and required only modest luminosity evolution with the steepening of the LF slope (α), except for a sudden steep increase in the B-band and a less steep increase in the U-band at faint magnitudes that required a starburst evolutionary model to account for the excess faint number counts. A cosmological model treating Hubble expansion as an Einstein curvature required less correction at faint magnitudes than a standard ΛCDM model, without requiring dark matter or dark energy. Data from DR17 of the SDSS in the g, i, r, u and z bands over two areas of the sky centred on the North Galactic Cap (NGC) and above the South Galactic Cap (SGC), with areas of 5954 and 859 sq. deg., respectively, and a combined count of 622,121 galaxies, were used to construct bright galaxy number counts and galaxy redshift/density plots within the limits of redshift ≤0.4 and mag ≤20. Their comparative densities confirmed an extensive void in the Southern sky with a deficit of 26% out to a redshift z ≤ 0.15. Although not included in the number count data set because of its incompleteness at fainter magnitudes, extending the SDSS redshift-number count survey to fainter and more distant galaxies with redshift ≤ 1.20 showed a secondary peak in the number counts with many QSOs, bright X-ray and radio sources, and evolving irregular galaxies with rapid star formation rates. This sub-population at redshifts of 0.45–0.65 may account for the excess counts observed in the B-band. Recent observations from the HST and James Webb Space Telescope (JWST) have also begun to reveal a high density of massive galaxies at high redshifts (z>7) with high UV and X-ray emissions, and future observations by the JWST may reveal the assembly of galaxies in the early universe going back to the first light in the universe.
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来源期刊
Galaxies
Galaxies Physics and Astronomy-Astronomy and Astrophysics
CiteScore
4.90
自引率
12.00%
发文量
100
审稿时长
11 weeks
期刊介绍: Es una revista internacional de acceso abierto revisada por pares que proporciona un foro avanzado para estudios relacionados con astronomía, astrofísica y cosmología. Areas temáticas Astronomía Astrofísica Cosmología Astronomía observacional: radio, infrarrojo, óptico, rayos X, neutrino, etc. Ciencia planetaria Equipos y tecnologías de astronomía. Ingeniería Aeroespacial Análisis de datos astronómicos. Astroquímica y Astrobiología. Arqueoastronomía Historia de la astronomía y cosmología. Problemas filosóficos en cosmología.
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