论文标题
本地卷中低质量巨人周围的矮星系丰富
The abundance of dwarf galaxies around low-mass giants in the Local Volume
论文作者
论文摘要
长期以来，卫星矮星系的丰度一直被认为是当前宇宙学模型的关键测试，导致众所周知的缺失卫星问题。模拟和观察结果的最新进展允许更详细地研究围绕宿主星系的矮星系。我们已经使用深色能量摄像机调查了附近雕塑家组的72 deg2区域 - 还包括位于该组后面的两个低质量局部体积星系NGC24和NGC45 - 以搜索迄今未发现的Dwarf Galaxies。除了先前已知的矮星系外，我们只发现了两个新的候选者，低至3 Sigma表面亮度检测极限为27.4 R MAG ARCSEC-2。这两个系统都在接近NGC24的投影中。但是，这些候选者之一可能是与背景星系相关的超湿星系。我们比较了NGC24，NGC45和其他五个精心研究的低质量巨型星系（NGC 1156，NGC2403，NGC2403，NGC5023，M33，M33和LMC）附近的已知矮星系候选候选者的数量，并在较低的模型上进行了访问，该模型是较低的模型。预期范围。这可能意味着在Lambdacdm中过度预测了Subhalos的过度预测，或者更有可能 - 由于观察到的偏见，我们缺少一些卫星成员。
The abundance of satellite dwarf galaxies has long been considered a crucial test for the current model of cosmology leading to the well-known missing satellite problem. Recent advances in both simulations and observations have allowed to study dwarf galaxies around host galaxies in more detail. We have surveyed a 72 deg2 area of the nearby Sculptor group using the Dark Energy Camera - also encompassing the two low-mass Local Volume galaxies NGC24 and NGC45 residing behind the group - to search for hitherto undetected dwarf galaxies. Apart from the previously known dwarf galaxies we have found only two new candidates down to a 3 sigma surface brightness detection limit of 27.4 r mag arcsec-2. Both systems are in projection close to NGC24. However, one of these candidates could be an ultra-diffuse galaxy associated to a background galaxy. We compared the number of known dwarf galaxy candidates around NGC24, NGC45, and five other well-studied low-mass giant galaxies (NGC 1156, NGC2403, NGC5023, M33, and the LMC) with predictions from cosmological simulations and found that for the stellar-to-halo mass models considered, the observed satellite numbers tend to be on the lower end of the expected range. This could either mean that there is an over-prediction of luminous subhalos in LambdaCDM or - and more likely - that we are missing some of the satellite members due to observational biases.
