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Cosmology using galaxy cluster peculiar velocities.

機(jī)譯：使用星系團(tuán)特殊速度的宇宙學(xué)。

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摘要

Future multi-frequency microwave background experiments with arcminute resolution and micro-Kelvin temperature sensitivity will be able to detect the kinetic Sunyaev-Zeldovich effect, providing a way to measure radial (line-of-sight) peculiar velocities of massive galaxy clusters. We show that measurement of cluster peculiar velocities have the potential to constrain several dark energy parameters. We also compare cluster peculiar velocities with other dark energy probes: the eventual constraints from radial peculiar velocity measurements on the dark energy parameters are comparable to constraints from supernovae measurements, and better than cluster counts and baryon acoustic oscillations; adding radial peculiar velocity to other dark energy probes improves constraints on the figure of merit by more than a factor of two.;We also study the impact of the mass-observable relation (i.e the relation between the observed Sunyaev-Zeldovich flux and the mass of the galaxy cluster) and other systematic errors on cluster radial peculiar velocities. We find that cluster radial peculiar velocities closely trace the large-scale peculiar velocity field independent of cluster mass. On the other hand, cluster radial peculiar velocity determinations are complicated by microwave emission from dusty galaxies and radio sources, which may be correlated with clusters. Systematic errors due to these factors can give substantial biases in determination of dark energy parameters, although radial peculiar velocity surveys will contain enough information that the errors can be modeled using the data itself, with little degradation in cosmological constraints.;An alternative to using the galaxy cluster radial peculiar velocity field directly is the cluster momentum distribution. Dark-matter cosmological simulations can provide the total cluster momentum distribution, while the Sunyaev-Zeldovich effect gives the baryon momentum. Thus, to better understand the cluster momentum distribution, we study the effect of quasar feedback on the baryon fraction in galaxy groups using high-resolution numerical simulations. For a sample of ten galaxy group-sized dark matter halos, the total gas fraction in the two simulations generally differs by less than 10%. We conclude that the quasar feedback do not add any significant systematic errors to the cluster momentum.;keywords: Cosmology: theory, Cosmology: Sunyaev-Zeldovich effect, cosmological parameters, galaxies: clusters, velocity, statistics.
機(jī)譯：未來具有弧分鐘分辨率和微開爾文溫度敏感性的多頻微波背景實(shí)驗(yàn)將能夠檢測(cè)出動(dòng)力學(xué)上的Sunyaev-Zeldovich效應(yīng)，從而提供了一種測(cè)量大規(guī)模星系團(tuán)的徑向（視線）速度的方法。我們表明，群集特殊速度的測(cè)量具有約束幾個(gè)暗能量參數(shù)的潛力。我們還將星團(tuán)特有的速度與其他暗能量探測(cè)器進(jìn)行了比較：暗能量參數(shù)上徑向特有速度測(cè)量的最終約束與超新星測(cè)量的約束相當(dāng)，并且優(yōu)于星團(tuán)計(jì)數(shù)和重子聲振蕩。向其他暗能量探測(cè)器中增加徑向特有速度，將對(duì)品質(zhì)因數(shù)的約束提高了兩倍以上；我們還研究了質(zhì)量可觀測(cè)關(guān)系（即觀測(cè)到的Sunyaev-Zeldovich通量與質(zhì)量之間的關(guān)系）的影響。星系團(tuán)的速度）和其他系統(tǒng)誤差對(duì)星團(tuán)徑向速度的影響。我們發(fā)現(xiàn)，簇的徑向奇特速度緊密地跟蹤了獨(dú)立于簇質(zhì)量的大規(guī)模奇特的速度場(chǎng)。另一方面，由于塵埃星系和無線電源發(fā)出的微波輻射使星團(tuán)的徑向速度異常確定，這可能與星團(tuán)相關(guān)。這些因素造成的系統(tǒng)誤差可能會(huì)在確定暗能量參數(shù)方面產(chǎn)生重大偏差，盡管徑向特殊速度調(diào)查將包含足夠的信息，使得可以使用數(shù)據(jù)本身對(duì)誤差進(jìn)行建模，而對(duì)宇宙學(xué)約束的影響很小。星系團(tuán)的徑向速度場(chǎng)直接是團(tuán)簇動(dòng)量的分布。暗物質(zhì)宇宙學(xué)模擬可以提供整個(gè)星團(tuán)的動(dòng)量分布，而Sunyaev-Zeldovich效應(yīng)可以提供重子動(dòng)量。因此，為了更好地了解星團(tuán)動(dòng)量分布，我們使用高分辨率數(shù)值模擬研究了類星體反饋對(duì)銀河系群中重子分?jǐn)?shù)的影響。對(duì)于十個(gè)星系組大小的暗物質(zhì)光環(huán)的樣本，兩次模擬中的總氣體分?jǐn)?shù)通常相差不到10％。我們得出結(jié)論，類星體反饋不會(huì)對(duì)星團(tuán)動(dòng)量增加任何明顯的系統(tǒng)誤差。關(guān)鍵詞：宇宙學(xué)：理論，宇宙學(xué)：Sunyaev-Zeldovich效應(yīng)，宇宙學(xué)參數(shù)，星系：團(tuán)簇，速度，統(tǒng)計(jì)。

著錄項(xiàng)

  • 作者

    Bhattacharya, Suman.;

  • 作者單位

    University of Pittsburgh.;

  • 授予單位 University of Pittsburgh.;
  • 學(xué)科 Physics Astronomy and Astrophysics.
  • 學(xué)位 Ph.D.
  • 年度 2008
  • 頁碼 120 p.
  • 總頁數(shù) 120
  • 原文格式 PDF
  • 正文語種 eng
  • 中圖分類
  • 關(guān)鍵詞

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