Warm-hot intergalactic baryons revealed
Warm-hot intergalactic baryons revealed
复制标题
温暖的星际重子揭晓
DOI：
10.1051/0004-6361:20021104
复制
发表时间：
2002
影响因子：
6.5
通讯作者：
D. Axon
中科院分区：
文献类型：
--
作者：
L. Zappacosta;F. Mannucci;R. Maiolino;R. Gilli;A. Ferrara;A. Finoguenov;N. Nagar;D. Axon
几个流行的宇宙学模型预测，本地宇宙中的大部分重子质量位于与星系超密度相关的星系和片状结构中。这种气体预计将被重力加热到106 K，因此发射软X射线。我们在高银河纬度ROSAT场中探测到了点源扣除和银河吸收校正后的弥散软X射线结构。这些扩散结构的X射线能量分布比预期的星团、星系团或活动星系核的未分辨发射要软得多，但与预期的扩散温暖的星系际介质一致。为了区分银河系或河外性质的扩散气体，我们在这一领域的多波段光学图像相关的软X-地图。我们已经发现了一个显着的超密度的星系对应的最强的扩散X射线结构。X射线峰上星系的光度红移分布在z = 0.45处超过场星系。这一结果强烈地表明，弥漫的X射线通量是由于与z = 0.45的过密星系区域相关的温暖气体的河外辐射。
Several popular cosmological models predict that most of the baryonic mass in the local universe is located in filamentary and sheet-like structures associated with galaxy overdensities. This gas is expected to be gravitationally heated to ∼10 6 K and therefore emitting in the soft X-rays. We have detected diffuse soft X-ray structures in a high Galactic latitude ROSAT field after point source subtraction and correction for Galactic absorption. These diffuse structures have an X-ray energy distribution that is much softer than expected from clusters, groups or unresolved emission from AGNs, but are consistent with that expected from a diffuse warm intergalactic medium. To discriminate between a Galactic or extragalactic nature of the diffuse gas we have correlated the soft X-map with multiband optical images in this field. We have found a significant overdensity of galaxies in correspondence with the strongest diffuse X-ray structure. The photometric redshift distribution of the galaxies over the X-ray peak has an excess over field galaxies at z ∼ 0.45. This result strongly suggests that the diffuse X-ray flux is due to extragalactic emission by warm gas associated with an overdense galaxy region at z ∼ 0.45.