DEEP CHANDRA MONITORING OBSERVATIONS OF NGC 4278: CATALOG OF SOURCE PROPERTIES
DEEP CHANDRA MONITORING OBSERVATIONS OF NGC 4278: CATALOG OF SOURCE PROPERTIES
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NGC 4278 的深度钱德拉监测观测：源属性目录
DOI：
10.1088/0067-0049/181/2/605
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Brassington N
中科院分区：
文献类型：
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作者：
Brassington N
本文介绍了钱德拉ACIS-S在6个不同的观测点观测到的富含球状星团（GC）的椭圆星系NGC 4278的离散x射线源的特性，共增加了458 k的曝光。从这次深度观测中，在所有观测重叠的区域内发现了236个源，其中180个位于星系的d25椭圆内。这236个源的lx范围从3.5× 10 36 erg s−1 （3σ上限≤1× 10 37 erg s−1）到~ 2× 10 40 erg s−1，包括被归类为LINER的中心核源。根据光学数据，确定了39个X射线源与GC重合，这些源往往具有较高的X射线光度，其中10个源表现为L X> 1× 10 38 erg s−1。从x射线源测光学中，已经确定236个具有良好约束颜色的点源中的大多数具有与典型的低质量x射线二元光谱一致的值，其中29个源预计是log N-log S关系中的背景物体。在这个群体中，有103个源表现出长期的变异性，表明它们是吸积的致密天体。其中三个源已被确定为暂态候选源，另外三个可能为暂态源。光谱变化也在大多数的源群中被确定，在那里已经确定了不同范围的变异性，表明在这个星系中有许多不同的源类。
We present the properties of the discrete X-ray sources detected in our monitoring program of the globular cluster (GC) rich elliptical galaxy, NGC 4278, observed with Chandra ACIS-S in six separate pointings, resulting in a co-added exposure of 458 ks. From this deep observation, 236 sources have been detected within the region overlapped by all observations, 180 of which lie within the D 25 ellipse of the galaxy. These 236 sources range in L X from 3.5× 10 36 erg s− 1 (with 3σ upper limit⩽ 1× 10 37 erg s− 1) to∼ 2× 10 40 erg s− 1, including the central nuclear source which has been classified as a LINER. From optical data, 39 X-ray sources have been determined to be coincident with a GC, these sources tend to have high X-ray luminosity, with 10 of these sources exhibiting L X> 1× 10 38 erg s− 1. From X-ray source photometry, it has been determined that the majority of the 236 point sources that have well-constrained colors have values that are consistent with typical low-mass X-ray binary spectra, with 29 of these sources expected to be background objects from the log N–log S relation. There are 103 sources in this population that exhibit long-term variability, indicating that they are accreting compact objects. Three of these sources have been identified as transient candidates, with a further three possible transients. Spectral variations have also been identified in the majority of the source population, where a diverse range of variability has been identified, indicating that there are many different source classes located within this galaxy.