A Multiwavelength View of the Neutron Star Binary 1FGL J1417.7–4402: A Progenitor to Canonical Millisecond Pulsars
A Multiwavelength View of the Neutron Star Binary 1FGL J1417.7–4402: A Progenitor to Canonical Millisecond Pulsars
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DOI：
10.3847/1538-4357/aadcab
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发表时间：
2018-08
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通讯作者：
S. Swihart;J. Strader;L. Shishkovsky;L. Chomiuk;A. Bahramian;C. Heinke;J. Miller-Jones;P. Edwards-P.-Edwa
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作者：
S. Swihart;J. Strader;L. Shishkovsky;L. Chomiuk;A. Bahramian;C. Heinke;J. Miller-Jones;P. Edwards-P.-Edwa
费米γ射线源1FGL J1417.7-4407（J1417）是一个紧凑的X射线双星，它有一颗中子星星和一颗红巨星伴星，轨道周期为5.4天。这一基于光学和X射线数据的初步结论，在与光学/X射线源相同的位置（并具有相同的轨道特性）发现了一颗2.66毫秒的射电脉冲星时得到了证实。然而，这些最初的研究发现了关于吸积状态和双星其他性质的相互矛盾的证据。我们提出了J1417的新的光学，无线电和X射线观测，使我们能够更好地了解这个不寻常的系统。我们表明，一个吸积盘的主要证据之一，以前提出的复杂形态的持久Hα发射线，可以更好地解释了存在一个强大的，磁驱动的恒星风从次级和它的相互作用与脉冲星风。从VLA/ATCA观测得到的射电光谱指数与毫秒脉冲星的预期大致一致，进一步不利于吸积盘的情况。X射线观测显示了双峰轨道光变曲线的证据，类似于在一些红背毫秒脉冲星双星中观察到的，可能是由于双星内的冲击。精确的光学光变曲线拟合给出了3.1 ± 0.6 kpc的距离，由盖亚DR 2视差测量证实。在这个距离上，J1417的X射线光度为（）×1033 erg s−1，比所有已知的红背系统在旋转动力脉冲星状态下更明亮，可能是由于来自巨伴星的风。这个系统的不寻常现象和它与红背毫秒脉冲星双星不同的演化路径指向一个新的食脉冲星“蜘蛛”子类，它可能是正常场毫秒脉冲星双星的祖先。
The Fermi γ-ray source 1FGL J1417.7–4407 (J1417) is a compact X-ray binary with a neutron star primary and a red giant companion in a ∼5.4 days orbit. This initial conclusion, based on optical and X-ray data, was confirmed when a 2.66 ms radio pulsar was found at the same location (and with the same orbital properties) as the optical/X-ray source. However, these initial studies found conflicting evidence about the accretion state and other properties of the binary. We present new optical, radio, and X-ray observations of J1417 that allow us to better understand this unusual system. We show that one of the main pieces of evidence previously put forward for an accretion disk—the complex morphology of the persistent Hα emission line—can be better explained by the presence of a strong, magnetically driven stellar wind from the secondary and its interaction with the pulsar wind. The radio spectral index derived from VLA/ATCA observations is broadly consistent with that expected from a millisecond pulsar, further disfavoring an accretion disk scenario. X-ray observations show evidence for a double-peaked orbital light curve, similar to that observed in some redback millisecond pulsar binaries and likely due to an intrabinary shock. Refined optical light-curve fitting gives a distance of 3.1 ± 0.6 kpc, confirmed by a Gaia DR2 parallax measurement. At this distance the X-ray luminosity of J1417 is ( ) ×1033 erg s−1, which is more luminous than all known redback systems in the rotational-powered pulsar state, perhaps due to the wind from the giant companion. The unusual phenomenology of this system and its differing evolutionary path from redback millisecond pulsar binaries points to a new eclipsing pulsar “spider” subclass that is a possible progenitor of normal field millisecond pulsar binaries.