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arXiv 0903.0330astro-ph.SR
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SDSS低质量白矮星脉冲星伴星的射电搜索

A Radio Search For Pulsar Companions To SDSS Low-Mass White Dwarfs

Marcel A. Agueros, Fernando Camilo, Nicole M. Silvestri, S. J. Kleinman, Scott F. Anderson, James W. Liebert

摘要:

我们用美国国家天文台绿岸望远镜(GBT)在820 MHz频率上对15颗低质量白矮星(M < 0.4 M_Sun)的脉冲星伴星进行了搜寻。这些LMWD在斯隆数字巡天(SDSS)中被光谱识别,并且在其发现数据中没有显示与伴星相关的光度过剩或光谱特征。然而,LMWD被认为是在双星系统中演化的,并且有一个更大质量的WD或中子星作为伴星。事实上,低质量X射线双星的演化模型,毫秒双星(MSP)的前身,产生了大量的LMWD(例如,Benvenuto & De Vito 2005),这表明SDSS LMWD可能有中子星伴星。在我们的数据中没有检测到令人信服的脉冲星信号。这与van Leeuwen等人(2007年)的发现一致,他们在340 MHz的射电脉动中进行了GBT搜索,从看不见的同伴到8个SDSS WD(5个仍然被认为是LMWD;其他3个现在被归类为“普通”WD)。我们讨论了我们的未检测放置在概率P_MSP的约束,即一个给定的LMWD的伴星是一个无线电脉冲星在我们的搜索的亮度和加速度限制的背景下,我们发现,P_MSP < 10 + 4 - 2%。

英文摘要:

We have conducted a search for pulsar companions to 15 low-mass white dwarfs (LMWDs; M < 0.4 M_Sun) at 820 MHz with the NRAO Green Bank Telescope (GBT). These LMWDs were spectroscopically identified in the Sloan Digital Sky Survey (SDSS), and do not show the photometric excess or spectroscopic signature associated with a companion in their discovery data. However, LMWDs are believed to evolve in binary systems and to have either a more massive WD or a neutron star as a companion. Indeed, evolutionary models of low-mass X-ray binaries, the precursors of millisecond pulsars (MSPs), produce significant numbers of LMWDs (e.g., Benvenuto & De Vito 2005), suggesting that the SDSS LMWDs may have neutron star companions. No convincing pulsar signal is detected in our data. This is consistent with the findings of van Leeuwen et al. (2007), who conducted a GBT search for radio pulsations at 340 MHz from unseen companions to eight SDSS WDs (five are still considered LMWDs; the three others are now classified as "ordinary" WDs). We discuss the constraints our non-detections place on the probability P_MSP that the companion to a given LMWD is a radio pulsar in the context of the luminosity and acceleration limits of our search; we find that P_MSP < 10 +4 -2 %.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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