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R Aquarii and Gamma Ray Astronomy R水瓶座与伽马射线天文学
Pub Date : 2018-06-06 DOI: 10.22323/1.315.0062
K. Tanabe, Y. Motizuki
In the Antarctic Ice core there exist many nitrate ion concentration spikes due to gamma ray. A part of the ice core extracted from the Japanese Antarctic station named Dome Fuji,corresponding with 11th century, shows three set of spikes.The first two possibly coincide with SN1006 and SN1054.The third one is probably due to the symbiotic binary R Auarii's outbursts (1073 and 1074AD)that were recorded in the ancient Korean documents as a "guest star". Moreover,there exist several nitrate ion spikes corresponding with other centuries. Some of the spikes without any historical records are possibly due to the gamma-ray from invisible or missing SNe or other (classical novae or symbiotic star )outbursts.
在南极冰芯中,由于伽马射线的作用,存在许多硝酸盐离子浓度峰值。从日本“富士圆顶”南极站提取的部分冰芯与11世纪相对应,显示出三组尖峰。前两个可能与SN1006和SN1054一致。第三个可能是共生双星金牛座R的爆发(公元1073年和1074年),在古代朝鲜文献中被记录为“客座星”。此外,还存在几个与其他世纪相对应的硝酸盐离子峰。一些没有任何历史记录的峰值可能是由于不可见或缺失的SNe或其他(经典新星或共生恒星)爆发的伽马射线。
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引用次数: 0
Search for CVs in wide-field narrow-band photometric survey 搜索宽视场窄带光度测量中的cv
Pub Date : 2018-06-06 DOI: 10.22323/1.315.0010
J. Abril, A. Ederoclite, L. Schmidtobreick
Cataclysmic Variables (CVs) are binary systems made of a white dwarf which is accreting mass from a less evolved companion. Depending on the physical properties of the system, the observational characteristics of CVs can be very diverse. Nevertheless, as we learned from projects like the Sloan Digital Sky Survey, CVs occupy the same locus of quasars in color-color diagrams, hence their discovery can be quite challenging. In this paper, we expose how the filter set of the J-PLUS project can help to efficiently separate CVs from other objects (mostly quasars) and even get their type. Through simulations and real data, we explain how accurate the method is and identify the following steps to finally get the first complete unbiased magnitude-limited sample of Cataclysmic Variables to date, a fundamental data set to be able to study the evolution of this type of objects.
大变星(cv)是由一颗白矮星从一颗进化程度较低的伴星那里吸积质量而形成的双星系统。根据系统的物理性质,cv的观测特征可以非常多样化。然而,正如我们从像斯隆数字巡天这样的项目中了解到的那样,cv在彩色图中占据了类星体的相同位置,因此它们的发现可能相当具有挑战性。在本文中,我们揭示了J-PLUS项目的过滤集如何帮助有效地从其他对象(主要是类星体)中分离cv,甚至获得它们的类型。通过模拟和实际数据,我们解释了该方法的准确性,并确定了以下步骤,以最终获得迄今为止第一个完全无偏的灾变数量级有限样本,这是能够研究这类对象演变的基本数据集。
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引用次数: 0
Photometry of OV Bootis at the Early Stage of 2017 Outburst 2017年爆发初期OV牧蹄星的光度测定
Pub Date : 2018-06-06 DOI: 10.22323/1.315.0044
K. Tanabe, H. Akazawa, N. Fukuda
We report our photometric observational results during the early stage of 2017 outburst of an ultra short orbital period cataclysmic variable star OV Bootis. From the obtained light curve, its period of the hump-like modulation is quite close to its orbital one This result suggests us that this variable star is thought to be neither WZ Sge-type nor SU UMa-type dwarf nova ,taking into account the absence of rebrightening.
我们报告了2017年超短轨道周期灾难性变星OV牧夫座爆发早期的光度观测结果。从获得的光曲线来看,它的峰状调制周期与轨道周期非常接近。这一结果表明,考虑到没有再增亮,我们认为这颗变星既不是WZ sge型的,也不是SU uma型的矮新星。
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引用次数: 0
Multifrequency behavior of classical novae 经典新星的多频行为
Pub Date : 2018-06-06 DOI: 10.22323/1.315.0047
I. Hachisu, M. Kato
We review our current understanding of multiwavelength light curves of classical and recurrent novae and show how to determine the WD masses and other binary properties. We pick up PW Vul, U Sco, V745 Sco, RS Oph, and V407 Cyg as representatives of different types of light curves, examine their light curves in detail, discuss physical properties, and clarify the reason of these differences. In the rising phase, the hydrogen-rich envelope expands beyond the size of a close binary in which the companion is embedded deep inside of the photosphere. After the optical maximum, the pseud-photosphere begins to shrink and an optically thin region develops outside of the photosphere. The free-free emission dominates the flux at relatively longer wavelengths (optical and NIR), of which light curves decay along the universal decline law of $F_nu propto t^{-1.75}$ (or $t^{-1.55}$). The physical mechanism of super-Eddington phase is presented. In the presence of shock interaction between ejecta and circumstellar matter, it slows down the decay of optical flux as $F_nu propto t^{-1.0}$ as seen in the early phase of V407 Cyg. In final stages of outbursts, the wind mass-loss rate sharply drops so the slope of free-free emission decays like $F_nu propto t^{-3.5}$. Supersoft X-ray phase begins and continues until hydrogen nuclear burning ends, and after that the nova enters a cooling phase. Hard X-rays may originate from internal shocks between ejecta (or a bow shock between ejecta and the companion). The behaviors of optical-dominant, UV-dominant, and supersoft X-ray source phase have different dependences on the WD mass and envelope chemical composition, so multiwavelength observations are useful to determine the parameters such as the WD mass. Finally, we should note that the very early phase of nova outbursts remains unexplored. An X-ray flash phase is theoretically identified, but not yet successfully detected. Detections of early X-ray flashes give direct information on thermonuclear runaway.
我们回顾了我们目前对经典新星和循环新星的多波长光曲线的理解,并展示了如何确定WD质量和其他双星特性。我们选取了PW Vul, U Sco, V745 Sco, RS Oph和V407 Cyg作为不同类型光曲线的代表,详细研究了它们的光曲线,讨论了它们的物理性质,并阐明了这些差异的原因。在上升阶段,富氢包层扩展到一个紧密的双星的大小之外,其中的伴星被深嵌在光球的内部。在光学最大值之后,伪光球开始收缩,在光球外形成一个光学薄区。在相对较长的波长(光学和近红外)处,自由-自由发射占主导地位,其光曲线沿$F_nu propto t^{-1.75}$(或$t^{-1.55}$)的普遍衰减规律衰减。提出了超爱丁顿相的物理机理。在抛射物和星周物质之间存在激波相互作用的情况下,它减缓了光通量的衰减,如$F_nu propto t^{-1.0}$所见,在V407 Cyg的早期阶段。在爆发的最后阶段,风的质量损失率急剧下降,使自由-自由发射的斜率衰减,如$F_nu propto t^{-3.5}$。超软x射线阶段开始并持续到氢核燃烧结束,之后新星进入冷却阶段。硬x射线可能来自弹射体之间的内部激波(或弹射体与伴星之间的弓形激波)。光优势相、紫外优势相和超软x射线源相的行为对WD质量和包膜化学成分有不同的依赖关系,因此多波长观测有助于确定WD质量等参数。最后,我们应该注意到新星爆发的早期阶段仍未被探索。理论上已经确定了x射线闪光相位,但尚未成功检测到。对早期x射线闪光的探测提供了关于热核失控的直接信息。
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引用次数: 0
Systematic search for post period-minimum cataclysmic variables: A short review 后时期最小灾变变量的系统搜索:简要回顾
Pub Date : 2018-06-06 DOI: 10.22323/1.315.0034
V. Neustroev, C. Knigge, S. Zharikov
Standard evolutionary theory suggests that cataclysmic variables (CVs) evolve from longer to shorter orbital periods. CVs that have passed beyond the period minimum and are evolving back towards longer periods are called the period bouncers. CVs of the WZ Sge-type have been long considered as potential period-bounce candidates. However, only very few of recently discovered WZ Sge-type stars were observed spectroscopically in quiescence due to their faintness. The lack of information on many of WZ Sge-type stars does not allow us to put restrictions on their system parameters and to confirm or deny their period bounce nature. Here we present a novel, simpler yet equally valuable approach based on multicolour broadband photometry to reveal the best period bounce candidates. By adopting such an approach, we performed a pilot study of a sample of WZ~Sge-type objects and accreting WDs and have found solid evidence for very low luminosity donor stars in several of them.
标准的进化理论认为,突变变量(cv)从较长的轨道周期进化到较短的轨道周期。已经超过周期最小值并且正在向更长的周期演变的cv被称为周期bouncer。长期以来,WZ - sge类型的简历一直被视为潜在的周期性反弹候选人。然而,在最近发现的WZ - sg型恒星中,由于亮度较弱,只有极少数在光谱上被观测到处于静止状态。由于缺乏关于许多WZ - sg型恒星的信息,我们无法对它们的系统参数加以限制,也无法确认或否认它们的周期反弹性质。在这里,我们提出了一种新颖的,更简单但同样有价值的方法,基于多色宽带光度法来揭示最佳的周期反弹候选者。通过采用这种方法,我们对WZ~ sge型天体和吸积WDs样本进行了初步研究,并在其中一些天体中发现了非常低光度的供体恒星的确凿证据。
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引用次数: 1
Old Novae: Old Glories with Bright Future 老新星:昔日辉煌,未来光明
Pub Date : 2018-06-06 DOI: 10.22323/1.315.0045
A. Ederoclite, C. Tappert, L. Schmidtobreick, N. Vogt
Classical novae are important astrophysical laboratories and are extremely relevant in several aspects of modern astronomy. A complete understanding of the nova phenomenon passes through the understanding not only of the phase where the nova is bright, but also understanding the properties of the binaries in which these events occur. This paper focusses on the properties of Cataclysmic Variables (CVs) which have harboured a nova explosion more than 30 years ago. The objects are analysed both in terms of CV population and in relation to their properties at maximum. Finally, we advice the reader on the proper steps in order to use old novae in the Gaia era.
经典新星是重要的天体物理实验室,在现代天文学的几个方面具有极其重要的意义。要全面了解新星现象,不仅要了解新星明亮的阶段,还要了解这些事件发生的双星的特性。本文主要讨论了30多年前发生新星爆炸的巨变星(cv)的性质。对这些对象进行了CV总体和其最大属性的分析。最后,我们建议读者在正确的步骤,以便在盖亚时代使用旧新星。
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引用次数: 0
Recurrent novae and long-term evolution of mass-accreting white dwarfs – toward the accurate mass retention efficiency 复发新星与质量吸积白矮星的长期演化——迈向精确的质量保持效率
Pub Date : 2017-11-05 DOI: 10.22323/1.315.0056
M. Kato, I. Hachisu, H. Saio
The mass growth rate of mass-accreting white dwarfs (WDs) is a key factor in binary evolution scenarios toward Type Ia supernovae. Many authors have reported very different WD mass increasing rates. In this review, we clarify the reasons for such divergence, some of which come from a lack of numerical techniques, usage of old opacities, different assumptions for binary configurations, inadequate initial conditions, and unrealistic mass-loss mechanisms. We emphasize that these assumptions should be carefully chosen in calculating the long-term evolution of accreting WDs. Importantly, the mass-loss mechanism is the key process determining the mass retention efficiency: the best approach involves correctly incorporating the optically thick wind because it is supported by the multiwavelength light curves of novae.
质量吸积白矮星(WDs)的质量增长速度是Ia型超新星双星演化场景的关键因素。许多作者报告了不同的WD质量增加速率。在这篇综述中,我们澄清了这种分歧的原因,其中一些是由于缺乏数值技术,使用旧的不透明,对二元结构的不同假设,不充分的初始条件,以及不现实的质量损失机制。我们强调,在计算逐渐增加的WDs的长期演变时,应谨慎选择这些假设。重要的是,质量损失机制是决定质量保持效率的关键过程:最好的方法包括正确地结合光学厚风,因为它是由新星的多波长光曲线支持的。
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引用次数: 4
X-ray and optical observations of polars 极地的x射线和光学观测
Pub Date : 2017-09-01 DOI: 10.22323/1.315.0019
H. Worpel, A. Schwope
The soft excess is a spectral feature shown by many polar cataclysmic variables, resembling a very luminous blackbody in soft X-rays. It is thought to arise from the accretion of discrete blobs of gas onto the WD, and was found in all polars discovered prior to the end of the ROSAT mission. All polars discovered since then seem to lack it, and the reason is still unknown. Here we present an XMM-Newton study of four polars discovered optically in recent years. All four lack the soft excess, and we test the hypothesis that the sought-after spectral feature might be concealed in the very soft X-ray regime unobservable by XMM-Newton.
软过剩是一个光谱特征,显示了许多极性突变变量,类似于一个非常明亮的黑体在软x射线。它被认为是由离散的气体团吸积到WD中产生的,并且在ROSAT任务结束之前发现的所有极地都发现了它。从那以后发现的所有极地似乎都缺乏它,原因仍然未知。在这里,我们介绍了xmm -牛顿对近年来光学上发现的四个极的研究。所有四种都缺乏软过剩,我们测试了一个假设,即人们追求的光谱特征可能隐藏在xmm -牛顿无法观测到的非常软的x射线区中。
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引用次数: 0
The Hot Components in the Recurrent Novae T Pyxidis, IM Norma, CI Aquilae and in the Dwarf Nova U Geminorum 旋回新星T Pyxidis, IM Norma, CI Aquilae和矮新星U Geminorum中的热成分
Pub Date : 2017-09-01 DOI: 10.22323/1.315.0058
E. Sion, P. Godon
We report on the latest results from Hubble Space Telescope (HST) far ultraviolet spectroscopy with the Cosmic Object Spectrograph (COS), of the short orbital period recurrent novae (RNe) T Pyxidis, IM Norma (the first ever FUV spectrum of this RN) and CI Aquilae, the only known recurrent novae with main sequence donors and orbital periods less than a day. The last two HST COS spectra we obtained in October, 2016 and June, 2016, reveal that the accretion rate of T Pyx has declined by 20% below its quiescent continuum flux level recorded by the IUE following the 1966 outburst, an indication that the system might not have yet reached its (new) quiescent state. Recent HST COS Spectroscopy of the cooling of the white dwarf in the prototypical dwarf nova U Geminorum is also discussed with a focus on the chemical abundances in the white dwarf photosphere.
我们报告了哈勃太空望远镜(HST)和宇宙物体光谱仪(COS)对短轨道周期复发新星(RNe) T Pyxidis, IM Norma(该RN的第一个FUV光谱)和CI Aquilae的最新结果,这是唯一已知的主序供体和轨道周期小于一天的复发新星。我们在2016年10月和2016年6月获得的最后两幅HST COS光谱显示,T Pyx的吸积速率比IUE记录的1966年爆发后的静态连续通量水平下降了20%,这表明该系统可能尚未达到(新的)静态状态。本文还讨论了典型矮新星U Geminorum中白矮星冷却的HST COS光谱,重点讨论了白矮星光球中的化学丰度。
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引用次数: 0
Long-lasting growing superhumps in SU UMa stars: QZ Vir 长期成长的超级humps在一个明星:QZ来
Pub Date : 2017-09-01 DOI: 10.22323/1.315.0014
A. Imada, Taichi Kato, K. Isogai
We report on the 2015 February-March superoutburst of the well known SU UMa-type dwarf novae QZ Vir (= T Leo). The light curve showed a unique feature in which the precursor was completely separated from the main superoutburst. During the stage between the precursor and main superoutburst, we detected superhumps with the mean period of 0.061181(42) d. Based on the amplitudes and $O - C$ analyses of superhumps, we identified the observed superhump during the faint stage as stage A superhumps. Using the orbital and stage A superhump period of QZ Vir, we derived the mass ratio to be 0.108(3). This value indicates that the system is an SU UMa-type dwarf novae evolving toward the period minimum. Here we briefly discuss that long-lasting growing superhumps can offer an opportunity to examine the evolutional status of SU UMa-type dwarf novae with moderate orbital periods, and future strategies of photometry of SU UMa-type dwarf novae.
我们报道了2015年2 - 3月著名的SU uma型矮新星QZ Vir (= T Leo)的超爆发。光曲线显示出一个独特的特征,即前驱体与主超突出完全分离。在前体和主超突出之间的阶段,我们探测到平均周期为0.061181(42)d的超级峰。根据超级峰的振幅和$O - C$分析,我们确定在微弱阶段观测到的超级峰为A级超级峰。利用QZ Vir的轨道和A级超峰周期,我们推导出质量比为0.108(3)。该值表明该系统是一颗向最小周期演化的SU - uma型矮新星。在此,我们简要地讨论了长时间生长的超级驼峰可以为研究中等轨道周期的SU - uma型矮新星的演化状态提供机会,以及SU - uma型矮新星光度测量的未来策略。
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引用次数: 0
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