New XMM-Newton observation of the thermally emitting isolated neutron star 2XMM J104608.7-594306
New XMM-Newton observation of the thermally emitting isolated neutron star 2XMM J104608.7-594306
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热发射孤立中子星的新 XMM-牛顿观测 2XMM J104608 7-594306
DOI：
10.1051/0004-6361/201526436
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发表时间：
2015
影响因子：
6.5
通讯作者：
Treves
中科院分区：
文献类型：
--
作者：
Turolla;Schwope;Treves
孤立的中子星星（INS）2XMM J104608.7-594306是自ROSAT时代以来通过热发射发现的仅有的两颗星之一。可能是船底座星云中前一代大质量恒星的遗迹，源的确切性质尚不清楚，它可能是银河系几类INS中唯一的一个。此外，吸收的光谱特征也已被确定。我们重新观察2XMM J104608.7-594306与XMM-Newton到更好地解释的光谱能量分布的源，确认候选的自旋周期，并可能限制脉冲星spin-down.MethodsWe使用的两个XMM-Newton观测2XMM J104608.7-594306进行详细的定时和光谱X射线分析。自旋下降率和能量的光谱特征提供估计的中子星星的磁场，这是至关重要的调查的中子星星的演化状态。结果统计上可接受的光谱拟合和有意义的物理参数的来源时，仅考虑到在能量为0.55千电子伏和1.35千电子伏的残差的光谱建模。前者可能是由于中子星星表面的不均匀温度分布造成的，或者可能与船底座星云中氧的局部过剩有关，而1.35 keV处的那个只能通过调用吸收线来令人满意地解释。在这种情况下，最适合的中子星星大气模型将氢柱密度、有效温度和源的光度限制在NH =（2.5−3.3）× 1021 cm-2、Teff=（6−10）× 105 K和LX =（1.1−7.4）× 1032 erg s-1。暗示的距离与船底座星云内（或前方）的位置一致，辐射半径与大部分表面的发射一致。非热X射线发射在源亮度的0.5%（3σ）以上的水平被排除。不幸的是，secondXMM-Newton观测证明不确定的确认（丢弃）的快速候选自旋，提供一个上限的脉冲分数的源，是非常接近的极限灵敏度检测的调制发现previous.ConclusionsIn没有一个明确的周期确定和估计的磁场，源的性质仍然开放的解释。它可能与船底座星系团和它的整体光谱特性（只有少数其他奇特的INS共享）相关联，不利于标准的进化路径或其中的源先前通过在双星系统中的吸积而再循环的路径。星星2XMM J104608.7-594306可能类似于卡尔韦拉（1 RXS J141256.0+792204），卡尔韦拉是一颗中子星星，其演化的反磁星已经被讨论过。需要更好的年龄估计和更深的无线电和γ射线限制，以进一步限制中子星星的演化状态。
ContextThe isolated neutron star (INS) 2XMM J104608.7-594306 is one of the only two to be discovered through their thermal emission since the ROSAT era. Possibly a remnant of a former generation of massive stars in the Carina nebula, the exact nature of the source is unclear, and it might be unique amongst the several classes of Galactic INSs.AimsIn a first dedicatedXMM-Newtonobservation of the source, we found intriguing evidence of a very fast spin period ofP~ 18.6 ms at the 4σconfidence level. Moreover, spectral features in absorption have also been identified. We re-observed 2XMM J104608.7-594306 withXMM-Newtonto better characterise the spectral energy distribution of the source, confirm the candidate spin period, and possibly constrain the pulsar spin-down.MethodsWe used the twoXMM-Newtonobservations of 2XMM J104608.7-594306 to perform detailed timing and spectral X-ray analysis. Both the spin-down rate and the energy of the spectral features provide estimates on the neutron star magnetic field, which are crucial for investigating the evolutionary state of the neutron star.ResultsStatistically acceptable spectral fits and meaningful physical parameters for the source are only obtained when the residuals at energies 0.55 keV and 1.35 keV are taken into account by the spectral modelling. While the former can result from the inhomogeneous temperature distribution on the surface of the neutron star or can be related to a local overabundance of oxygen in the Carina nebula, the one at 1.35 keV is only satisfactorily accounted for by invoking a line in absorption. In this case, the best-fit neutron star atmosphere models constrain the hydrogen column density, the effective temperature, and the luminosity of the source withinNH= (2.5−3.3) × 1021cm-2,Teff= (6−10) × 105K, andLX= (1.1−7.4) × 1032erg s-1. The implied distance is consistent with a location in (or in front of) the Carina nebula, and radiation radii are compatible with emission originating on most of the surface. Non-thermal X-ray emission is ruled out at levels above 0.5% (3σ) of the source luminosity. Unfortunately, the secondXMM-Newtonobservation proved inconclusive in terms of confirming (discarding) the fast candidate spin, providing an upper limit on the pulsed fraction of the source that is very close to the limiting sensitivity for detecting the modulation found previously.ConclusionsIn the absence of an unambiguous period determination and an estimate of the magnetic field, the nature of the source remains open to interpretation. Its likely association with the Carina cluster and its overall spectral properties (only shared by a handful of other peculiar INSs) disfavour a standard evolutionary path or one in which the source was previously recycled by accretion in a binary system. The star 2XMM J104608.7-594306 may be similar to Calvera (1RXS J141256.0+792204), a neutron star for which the scenario of an evolved anti-magnetar has been discussed. A better age estimate and deeper radio andγ-ray limits are required to further constrain the evolutionary state of the neutron star.
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在 2XMMp 目录中搜索热发射孤立中子星
DOI：
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发表时间：
2009
期刊：
影响因子：
--
作者：
A. Pires;C. Motch;Eduardo Janot;Strasbourg;France.;IAG;Brazil.
通讯作者：
Brazil.
SDSS 数据发布 4 中没有确认新的孤立中子星
DOI：
--
发表时间：
2011
期刊：
影响因子：
--
作者：
M. Agüeros;B. Posselt;S. Anderson;P. Rosenfield;F. Haberl;L. Homer;B. Margon;Emily Newsom;W. Voges
通讯作者：
W. Voges
来自古尔德带的年轻孤立中子星
影响因子：
6.5
作者：
S. Popov;M. Colpi;M. Prokhorov;A. Treves;R. W. A. Institute;U. Milano;Universita' dell'Insubria;U. Padova
通讯作者：
U. Padova
1E 1207.4–5209 260 ks XMM-Newton 数据的详细光谱分析以及 2.1 keV 吸收特征的意义
DOI：
10.1086/432632
发表时间：
2004
期刊：
The Astrophysical Journal
影响因子：
--
作者：
K. Mori;James C. Chonko;C. Hailey
通讯作者：
C. Hailey
DOI：
10.1016/j.cpc.2012.04.029
发表时间：
2012-04
期刊：
Comput. Phys. Commun.
影响因子：
--
作者：
D. Viganò;J. Pons;J. Miralles
通讯作者：
D. Viganò;J. Pons;J. Miralles