A Possible New Population of Sources with Extreme X-Ray/Optical Ratios
A Possible New Population of Sources with Extreme X-Ray/Optical Ratios
复制标题
具有极端 X 射线/光学比率的可能的新光源群
DOI：
--
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
C. Urry
中科院分区：
文献类型：
--
作者：
A. Koekemoer;D. Alexander;F. Bauer;Jacqueline Bergeron;W. Brandt;E. Chatzichristou;S. Cristiani;S. M. Fall;N. Grogin;M. Livio;V. Mainieri;L. Moustakas;P. Padovani;P. Rosati;E. Schreier;C. Urry
我们描述了一种可能的新的X射线源，具有强大的检测超深钱德拉数据，但没有检测在所有在我们的深多波段大天文台起源深调查哈勃太空望远镜高级相机的调查（ACS）的图像，这代表了最高质量的光学成像获得这些领域的日期。这些极端的X射线/光学比源（EXO）的FX/Fopt值至少比其他活动星系核（AGN）的FX/Fopt值高出一个数量级，即使是那些被红化的宿主所隐藏的活动星系核。因此，我们推断出两种可能的情况：（1）如果这些源位于红移z = 6，那么与其他已知源相比，它们的宿主需要非常不亮或更红，或者（2）如果这些源位于z ~ 6-7以上，那么即使它们的Lyα发射也会红移到我们的ACS z 850滤波器的带通之外，则它们的光通量和X射线通量可以用相对正常的~L* 寄主和中等光度活动星系核来解释。
We describe a possible new class of X-ray sources that have robust detections in ultradeep Chandra data yet have no detections at all in our deep multiband Great Observatories Origins Deep Survey Hubble Space Telescope Advanced Camera for Surveys (ACS) images, which represent the highest quality optical imaging obtained to date on these fields. These extreme X-ray/optical ratio sources (EXOs) have values of FX/Fopt at least an order of magnitude above those generally found for other active galactic nuclei (AGNs), even those that are harbored by reddened hosts. We thus infer two possible scenarios: (1) if these sources lie at redshifts z ≲ 6, then their hosts need to be exceedingly underluminous or more reddened, compared with other known sources, or (2) if these sources lie above z ~ 6-7, such that even their Lyα emission is redshifted out of the bandpass of our ACS z850 filter, then their optical and X-ray fluxes can be accounted for in terms of relatively normal ~L* hosts and moderate-luminosity AGNs.