利用热Sunyaev-Zel'dovich效应探测超星系团中的团间气体
Detection of intercluster gas in superclusters using the thermal Sunyaev-Zel'dovich effect
摘要：
使用热Sunyaev-Zel'dovich（tSZ）信号，我们搜索超星系团中的热气体，使用斯隆数字巡天数据发布7（SDSS/DR 7）星系。我们堆叠康普顿化y地图由普朗克协作周围的超星系团和检测的tSZ信号在6.4西格玛的意义。我们进一步寻找超星系团中的气体团间成分。为此，我们通过掩蔽普朗克tSZ、ROSAT X射线和SDSS光学巡天探测到的所有星系群/星系团，将超星系团中的团内气体去除到10^13兆太阳的总质量。我们报道了在y =（3.5 +-1.4）* 10^（-8）的超星系团中首次探测到团间气体，其显著性为2.5 sigma。假设超星系团上的星系团间气体的密度分布是一个简单的等温和平坦的分布，估计的重子密度为（Omega_gas / Omega_b）*（T_e/（8*10^6 K））= 0.067 +- 0.006 +- 0.025。这个量与温度成反比，因此从模拟和观测中得出的值，我们发现超星系团中的气体密度可能占低红移时丢失重子的17 - 52%。更好地理解气体在超星系团中的物理状态，需要准确地估计我们的测量对失踪重子的贡献。
英文摘要：
Using a thermal Sunyaev-Zel'dovich (tSZ) signal, we search for hot gas in superclusters identified using the Sloan Digital Sky Survey Data Release 7 (SDSS/DR7) galaxies. We stack a Comptonization y map produced by the Planck Collaboration around the superclusters and detect the tSZ signal at a significance of 6.4 sigma. We further search for an intercluster component of gas in the superclusters. For this, we remove the intracluster gas in the superclusters by masking all galaxy groups/clusters detected by the Planck tSZ, ROSAT X-ray, and SDSS optical surveys down to a total mass of 10^13 Msun. We report the first detection of intercluster gas in superclusters with y = (3.5 +- 1.4) * 10^(-8) at a significance of 2.5 sigma. Assuming a simple isothermal and flat density distribution of intercluster gas over superclusters, the estimated baryon density is (Omega_gas / Omega_b) * (T_e/(8*10^6 K)) = 0.067 +- 0.006 +- 0.025. This quantity is inversely proportional to the temperature, therefore taking values from simulations and observations, we find that the gas density in superclusters may account for 17 - 52 % of missing baryons at low redshifts. A better understanding of the physical state of gas in the superclusters is required to accurately estimate the contribution of our measurements to missing baryons.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
