论文标题
本地宇宙中超X射线源的普查
A census of ultraluminous X-ray sources in the local Universe
论文作者
论文摘要
使用Chandra源目录2.0和本地宇宙中新汇编的星系目录，我们在附近星系中提供了超大型X射线源（ULX）种群的人口普查。我们在309个星系中发现629个ULX候选者，距离小于40 \ mpc。前景/背景污染为$ {\ sim} 20 \％$。以恒星形成率（SFR）和恒星质量（$ m_ \ star $）平均以真正的恒星形成星系尺度的ULX人群平均规模，以至于每个星系的ULX数量为$ 0.45^{+0.06} _ { - 0.09} _ { - 0.09}} m_ \ odot \，yr^{ - 1}}} {+} 3.3^{+3.8} _ { - 3.2} \ times \ frac \ frac {m_ \ star} {\ rm m_ \ odot} $。缩放量很大程度上取决于形态类型。该分析表明，早期的螺旋星系包含额外的ulx人群，这些ULX以$ m_ \ star $缩放。我们还证实了宿主星系的金属性对ULX速率的强抗相关性。在早期型星系的情况下，我们发现具有$ M_ \ star $的ULX数量是非线性依赖性的，这被解释为恒星形成历史差异的结果。考虑到年龄和金属性效应，我们发现X射线二元种群合成模型的预测与早期型星系中观察到的ULX速率以及螺旋/不规则星系一致。
Using the Chandra Source Catalog 2.0 and a newly compiled catalogue of galaxies in the local Universe, we deliver a census of ultraluminous X-ray source (ULX) populations in nearby galaxies. We find 629 ULX candidates in 309 galaxies with distance smaller than 40\,Mpc. The foreground/background contamination is ${\sim}20\%$. The ULX populations in bona-fide star-forming galaxies scale on average with star-formation rate (SFR) and stellar mass ($M_\star$) such that the number of ULXs per galaxy is $0.45^{+0.06}_{-0.09}\times\frac{\rm SFR}{\rm M_\odot\,yr^{-1}}{+}3.3^{+3.8}_{-3.2}\times\frac{M_\star}{\rm M_\odot}$. The scaling depends strongly on the morphological type. This analysis shows that early spiral galaxies contain an additional population of ULXs that scales with $M_\star$. We also confirm the strong anti-correlation of the ULX rate with the host galaxy's metallicity. In the case of early-type galaxies we find that there is a non-linear dependence of the number of ULXs with $M_\star$, which is interpreted as the result of star-formation history differences. Taking into account age and metallicity effects, we find that the predictions from X-ray binary population synthesis models are consistent with the observed ULX rates in early-type galaxies, as well as, spiral/irregular galaxies.
