Matched-filtering Line Search Methods Applied to Suzaku Data
Matched-filtering Line Search Methods Applied to Suzaku Data
复制标题
应用于朱雀数据的匹配过滤行搜索方法
DOI：
10.1093/pasj/psw091
复制
发表时间：
2016
影响因子：
2.3
通讯作者：
T. Ohashi
中科院分区：
文献类型：
--
作者：
N. Miyazaki;S. Yamada;T. Enoto;M. Axelsson;T. Ohashi
发射和吸收线的详细搜索和评估其上限进行朱雀数据。该方法利用匹配滤波的方法，以最大限度地提高信噪比为一个给定的能量分辨率，这可能适用于许多类型的线搜索。我们首先将其应用于已知的活动星系核光谱，已被报道有超快流出，并发现我们的结果是一致的，与以前的研究结果在103 σ水平。我们继续在两颗明亮的磁星4U 0142+61和1 RXS J1708−4009中寻找发射和吸收特征，并将滤波方法应用于朱雀数据。我们发现，即使使用长期的朱雀观测或将其光谱分为自旋相位，也没有任何来源显示出任何显着的线特征。发射/吸收线的等效宽度的上限被限制为在0.1keV处为几eV，在0.10keV处为几百eV。这加强了以前的报告，持续明亮的磁星在软X射线中不显示质子回旋吸收特征，即使它们存在，它们也会比X射线CCD的检测限更宽或更弱。
A detailed search for emission and absorption lines and an assessment of their upper limits are performed for Suzaku data. The method utilizes a matched-filtering approach to maximize the signal-to-noise ratio for a given energy resolution, which could be applicable to many types of line search. We first applied it to well-known active galactic nuclei spectra that have been reported to have ultra-fast outflows, and find that our results are consistent with previous findings at the ∼3σ level. We proceeded to search for emission and absorption features in two bright magnetars 4U 0142+61 and 1RXS J1708−4009, applying the filtering method to Suzaku data. We found that neither source showed any significant indication of line features, even using long-term Suzaku observations or dividing their spectra into spin phases. The upper limits on the equivalent width of emission/absorption lines are constrained to be a few eV at ∼1 keV and a few hundreds of eV at ∼10 keV. This strengthens previous reports that persistently bright magnetars do not show proton cyclotron absorption features in soft X-rays and, even if they exist, they would be broadened or much weaker than below the detection limit of X-ray CCD.