Multiwavelength Observations of a New Redback Millisecond Pulsar 4FGL J1910.7−5320
Multiwavelength Observations of a New Redback Millisecond Pulsar 4FGL J1910.7−5320
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DOI：
10.3847/1538-4357/acae8a
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发表时间：
2022-12
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通讯作者：
Ka-Yui Au;J. Strader;S. Swihart;L. Lin;A. Kong;J. Takata;C. Hui;T. Panurach;I. Molina;E. Aydi;K. Sokolovsky;Kwan-Lok Li
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作者：
Ka-Yui Au;J. Strader;S. Swihart;L. Lin;A. Kong;J. Takata;C. Hui;T. Panurach;I. Molina;E. Aydi;K. Sokolovsky;Kwan-Lok Li
我们提出了对一个未识别的费米大面积望远镜（LAT）源4FGL J1910.7−5320的多波长观测研究，这是一个新的候选红背毫秒脉冲星双星。在4FGL J1910.7−5320的4FGL 95%误差区域，我们发现了一个可能的双星，其轨道周期为8.36小时，由卡塔琳娜实时瞬变巡天（Catalina实时瞬变巡天）提供，并由SOAR望远镜的光谱学证实。这个光源是最近由TRAPUM项目独立发现的红背脉冲星，证实了我们的预测。我们用黑体模型拟合了4FGL J1910.7 - 5320的光谱能量分布，通过假设伴星以半径R = 0.7 R☉填充其罗氏叶，推断出其最大距离为4.1 kpc。利用12.6 ks钱德拉x射线观测，我们确定了4FGL J1910.7−5320的x射线对应体，其光谱可以用光子指数为1.0±0.4的吸收幂定律描述。光谱硬x射线发射显示了轨道变异性的初步证据。利用超过12年的Fermi-LAT数据，我们改进了γ射线源的位置，光学候选点仍然在68%的位置误差范围内。除了4FGL J1910.7−5320外，我们还在另一个未知费米源4FGL J2029.5−4237的4FGL目录95%误差区域内发现了一个周期信号为4.28 hr的可变光源。然而，在钱德拉的11.7 ks观测中，γ射线源没有明显的x射线对应，3σ通量上限为2.4 × 10−14 erg cm−2 s−1 （0.3-7 keV）。此外，光源在我们更新的费米- lat 95%误差圈之外。这些观测事实都表明，这颗新的红背毫秒脉冲星为伽马射线源4FGL J1910.7 - 5320提供动力，而4FGL J2029.5 - 4237不太可能是4.28小时变量的γ射线对应体。
We present the study of multiwavelength observations of an unidentified Fermi Large Area Telescope (LAT) source, 4FGL J1910.7−5320, a new candidate redback millisecond pulsar binary. In the 4FGL 95% error region of 4FGL J1910.7−5320, we find a possible binary with a 8.36 hr orbital period from the Catalina Real-Time Transient Survey, confirmed by optical spectroscopy using the SOAR telescope. This optical source was recently independently discovered as a redback pulsar by the TRAPUM project, confirming our prediction. We fit the optical spectral energy distributions of 4FGL J1910.7−5320 with a blackbody model, inferring a maximum distance of 4.1 kpc by assuming that the companion fills its Roche lobe with a radius of R = 0.7 R ☉. Using a 12.6 ks Chandra X-ray observation, we identified an X-ray counterpart for 4FGL J1910.7−5320, with a spectrum that can be described by an absorbed power law with a photon index of 1.0 ± 0.4. The spectrally hard X-ray emission shows tentative evidence for orbital variability. Using more than 12 yr of Fermi-LAT data, we refined the position of the γ-ray source, and the optical candidate still lies within the 68% positional error circle. In addition to 4FGL J1910.7−5320, we find a variable optical source with a periodic signal of 4.28 hr inside the 4FGL catalog 95% error region of another unidentified Fermi source, 4FGL J2029.5−4237. However, the γ-ray source does not have a significant X-ray counterpart in an 11.7 ks Chandra observation, with a 3σ flux upper limit of 2.4 × 10−14 erg cm−2 s−1 (0.3–7 keV). Moreover, the optical source is outside our updated Fermi-LAT 95% error circle. These observational facts all suggest that this new redback millisecond pulsar powers the gamma-ray source 4FGL J1910.7−5320 while 4FGL J2029.5−4237 is unlikely the γ-ray counterpart to the 4.28 hr variable.