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1.
The famous ancient supernova SN 1054 could have been too bright to be explained in the "standard" radioactive-powered supernova scenario. As an alternative attempt, we demonstrate that the spin-down of the newly born Crab pulsar could provide a sufficient energy supply to make SN 1054 visible at daytime for 23 days and at night for 653 days, where a one-zone semi-analytical model is employed. Our results indicate that SN 1054 could be a "normal" cousin of magnetar-powered superluminous supernovae. Therefore, SN 1054-like supernovae could be a probe to uncover the properties of newly born neutron stars, which provide initial conditions for studies on neutron star evolutions.  相似文献   

2.
本文给出北京天文台2.16m望远镜SN1993J光谱观测结果.  相似文献   

3.
We briefly report on our observations of SN 1979c in NGC 4321 in the period 1979 April 23 – December 27.The light curve of SN 1979c shows a hump in the period May 8 – June 5. It thus differs from a Type-I curve, but it does not completely agree with a typical Type-II curve either. Using our own and others' data, we find that, at maximum, it had an absolute photographic magnitude of ?19m.78 and a colour temperature of ～9000 K. We estimate the total energy release to be 1.6 × 1050 erg. We also note its location on a spiral arm of the parent galaxy, not far from an H-II region. From these observations, we conclude that SN 1979c is a Type-II supernova with, however, some atypical features.  相似文献   

4.
We present a deep [O  iii ]λλ4959,5007 image of the northern filamentary jet in the Crab Nebula taken with the 8.2-m Subaru telescope. Using this image and an image taken with the Kitt Peak National Observatory (KPNO) 4-m in 1988, we have computed proper motions for 35 locations in the jet. The results suggest that when compared to the main body of the remnant, the jet experienced less outward acceleration from the central pulsar's rapidly expanding synchrotron nebula. The jet's apparent expansion rate yields an undecelerated explosion date for the Crab Nebula of 1055 ± 24 CE, a date much closer to the appearance of the historic 1054 CE guest star than the 1120–1140 CE dates estimated in previous studies using filaments located within the remnant's main nebula. Our proper motion measurements suggest the jet likely formed during the 1054 supernova explosion and represents the remnant's highest velocity knots possibly associated with a suspected N–S bipolar outflow from the supernova explosion.  相似文献   

5.
We propose to use a global (wide-angle, of the order of several degrees) distribution of linearly polarized emission over the sky to detect light echoes of historical supernovae exploded in our Galaxy. The echo emission must be polarized tangential to the direction of the supernova explosion site, and its degree of polarization must exhibit a characteristic dependence on angular distance. The near infrared is an optimum spectral range for detection. A spotted structure in the shape of a ring ～5° in diameter and ～3° in width with a total brightness of ～12–13m in polarized light with a tangential orientation of the electric vector must be currently seen in the direction where Tycho Brahe observed a supernova explosion in 1572. A comparison of the expected intensity of the echo with the intensities of the zodiacal light and the atmosphere shows that it can be detected in principle during long-term observations from space and, under favorable conditions, even from the ground.  相似文献   

6.
宇宙线的起源是高能天体物理的核心问题之一.一直以来,超新星爆发被认为是能谱膝区以下宇宙线的主要来源.多波段观测表明,超新星遗迹有能力加速带电粒子至亚PeV (10~(15)eV)能量.扩散激波加速被认为是最有效的天体高能粒子加速机制之一,而超新星遗迹的大尺度激波正好为这一机制提供平台.近年来,一系列较高精度的地面和空间实验极大地推动了对宇宙线以及超新星遗迹的研究.新的观测事实挑战着传统的扩散激波加速模型以及其在银河系宇宙线超新星遗迹起源学说上的应用,深化了人们对宇宙高能现象的认识.结合超新星遗迹辐射能谱的时间演化特性,构建的时间依赖的超新星遗迹粒子加速模型,不仅能够解释200 GV附近宇宙线的能谱反常,还自然地形成能谱膝区,甚至可以将超新星遗迹粒子加速对宇宙线能谱的贡献延伸至踝区.该模型预期超新星遗迹中粒子的输运行为表现为湍流扩散,这需要未来的观测以及与粒子输运相关的等离子体数值模拟工作来进一步验证.  相似文献   

7.
A massive binary, in which the primary becomes a supernova, should leave a luminous secondary near the centre of its remnant. Contrary to expectation no statistically significant excess of OB stars is, however, found near the centres of optically visible galactic supernova remnants.  相似文献   

8.
We model the interaction of the supernova SN 1995G with a dense circumstellar (CS) gas in a thin-shell approximation. A model fit to the observed bolometric light curve combined with data on the supernova expansion velocity gives estimates for the density, mass (≈1 M⊙), and age (≈8 yr) of the CS envelope. The determined CS-envelope density is shown to be virtually independent of the assumed mass of the supernova envelope because of the high CS-gas density at which the forward shock wave is essentially radiative. The derived CS-envelope density is consistent with the Hα luminosity and with the presence of distinct Thomson scattering in the red wing of this line. The mass of the CS envelope together with its expansion velocity and age indicate that the CS envelope was ejected by the presupernova eight years before the supernova explosion through violent energy release (～6×1048 erg).  相似文献   

9.
Kaare Aksnes  Fred Franklin 《Icarus》1984,60(1):180-188
A thorough search covering more than 3 years shows that nearly 300 observable mutual eclipses and occultations of the Galilean satellites occur between May 1985 and April 1986, marking this apparition as a very favorable one. This paper tabulates quantities needed to obtain light curves of all events, excluding only those taking place either too close to Jupiter or with the planet too near the Sun. Since observations are relatively short and easy to incorporate into photometric programs, we urge an active campaign so as to provide the accurate astrometric data required to improve ephemerides (which are of immediate interest to the Galileo mission to Jupiter) and to look for tidal effects in the motion of Io.  相似文献   

10.
ASASSN-15lh is a super luminous supernova, whose light curve is similar to that of the type Ia supernova (SN Ia). Since the luminosity of SN Ia is directly related to the decay of 56Ni, in this paper, we consider the de-excitation energy of the new nuclei, and calculate the energy generated by the decay of 56Ni in the explosive environment of ASASSN-15lh. The calculated mass of 56Ni needed by the ASASSN-15lh explosion is 31.32 M⊙. This result agrees with the estimation of the mass of 56Ni ≥ 30 M⊙ derived from the observed light curve of ASASSN-15lh. No agreement has reached for the explosion mechanism of supernova ASASSN-15lh so far. The calculation in this paper provides a reference for the further study on the progenitor and explosion mechanism of the supernova ASASSN-15lh.  相似文献   

11.
Masers at the ground-state OH satellite transitions near 1612 and 1720 MHz are occasionally found in star-forming regions, accompanying the dominant maser of OH at 1665 MHz. The satellite lines can then be valuable diagnostics of physical conditions in star-forming regions if we can first ascertain that all maser species truly arise from the same site. For this purpose, newly measured satellite line positions with subarcsecond accuracy are reported here, and compared with masers of main-line OH at 1665 MHz, with methanol masers at 6668 MHz, and with ultracompact H  ii regions. We confirm that most of the satellite-line OH masers that we have measured are associated with star-forming regions, but a few are not: several 1612-MHz masers are associated with late-type stars, and one 1720-MHz maser is associated with a supernova remnant. The 1720-MHz masers in star-forming regions are accounted for by a pumping scheme requiring high densities, and are distinctly different from those in supernova remnants where the favoured pumping scheme operates at much lower densities.  相似文献   

12.
SN 2011fe was the nearest and best-observed type Ia supernova in a generation, and brought previous incomplete datasets into sharp contrast with the detailed new data. In retrospect, documenting spectroscopic behaviors of type Ia supernovae has been more often limited by sparse and incomplete temporal sampling than by consequences of signal-to-noise ratios, telluric features, or small sample sizes. As a result, type Ia supernovae have been primarily studied insofar as parameters discretized by relative epochs and incomplete temporal snapshots near maximum light. Here we discuss a necessary next step toward consistently modeling and directly measuring spectroscopic observables of type Ia supernova spectra. In addition, we analyze current spectroscopic data in the parameter space defined by empirical metrics, which will be relevant even after progenitors are observed and detailed models are refined.  相似文献   

13.
对年轻超新星遗迹的射电观测有助于理解超新星遗迹的早期演化. 选取银河系最年轻的超新星遗迹\lk G1.9+0.3进行了研究. 收集了已有的射电流量密度测量, 转化到同一频率, 从而获得了G1.9+0.3的流量密度在过去近50 yr的演化. 发现流量密度在2008年之前几乎一直在增加, 随后开始减小, 流量密度达到峰值的年龄约为\lk 150--155 yr. 流量密度的增加可能由磁场放大或者粒子加速效率提高产生的高能电子增多导致. 根据流量密度到达峰值的年龄, 结合前人的数值模拟, 讨论了超新星抛射物的质量和超新星爆发释放的动能.  相似文献   

14.
We investigate the method by which nearby supernovae – within a few tens of pc of the solar system – can penetrate the solar system and deposit live radioactivities on earth. The radioactive isotopic signatures that could potentially leave an observable geological imprint are in the form of refractory metals; consequently, it is likely they would arrive in the form of supernova-produced dust grains. Such grains can penetrate into the solar system more easily than the bulk supernova plasma, which gets stalled and deflected near the solar system due to the solar wind plasma pressure. We therefore examine the motion of charged grains as they decouple from the supernova plasma and are influenced by the solar magnetic, radiation, and gravitational fields. We characterize the dust trajectories with analytical approximations which display the roles of grain size, initial velocity, and surface voltage. These results are verified with full numerical simulations for wide ranges of dust properties. We find that supernova dust grains traverse the inner solar system nearly undeflected, if the incoming grain velocity – which we take to be that of the incident supernova remnant – is comparable to the solar wind speeds and much larger than the escape velocity at 1 AU. Consequently, the dust penetration to 1 AU has essentially 100% transmission probability and the dust capture onto the earth should have a geometric cross section. Our results cast in a new light the terrestrial deposition of radioisotopes from nearby supernovae in the geological past. For explosions beyond ～10 pc from earth, dust grains can still deliver supernova ejecta to earth, and thus the amount of supernova material deposited is set by the efficiency of dust condensation and survival in supernovae. Turning the problem around, we use observations of live 60Fe in both deep-ocean and lunar samples to infer a conservative lower bound iron condensation efficiency of Mdust,Fe/Mtot,Fe ? 4  × 10?4 for the supernova which apparently produced these species 2–3 Myr ago.  相似文献   

15.
Book reviews     
The possibility of the existence, around type-I supernovae, of dust shells which existed before a supernova outburst is considered. None have so far been detected observationally; and any dust around the progenitor radiating in the near infrared would evaporate at outburst. Far infrared observations of the two possible types of progenitor, R Coronae Borealis-type stars and dwarf novae, would be useful to indicate whether there is any dust around them which would survive a supernova outburst.  相似文献   

16.
The 13.7-m millimeter-wave radio telescope of Purple Mountain Observatory operates at 3200-m above the sea level near Delingha, Qinghai Province, China. Equipped with a superconducting SIS receiver, the telescope is used in the millimeter-wave band ranging from 85 to 115 GHz. An upgrade procedure is reported here which includes a superconducting SIS receiver, a new phase-locked local oscillator, a dedicated multi-line backend system, and a new control system based on industrial computer with PCI bus. With the dedicated multi-line backend system, the CO and isotopic lines around 110 GHz are obtained simultaneously. In recent years, scientific activities with this telescope have been focused on studies of Galactic molecular clouds and star formation regions, including surveys of molecular lines from IRAS sources and large-scale map of molecular clouds. Other programs include studies of the circumstellar envelope of late-type stars and interaction of Galactic supernova remnants with dense molecular gas.  相似文献   

17.
Observations of two infrared objects embedded in molecular clouds near the supernova remnant W44 are presented. W44-IRS1 offers compelling evidence that it is a star whose formation was recently induced by expansion of the supernova remnant. W44-IRS2 lies beyond the remnant, possibly apart from the region of its influence.Paper presented at the Conference on Protostars and Planets, held at the Planetary Science Institute, University of Arizona, Tucson, Arizona, between January 3 and 17, 1978.Kitt Peak National Observatory which is operated by AURA. Inc. under contract with the National Science Foundation.  相似文献   

18.
Radio observations of young supernova remnants (SNRs) can shed light on the early evolution of SNRs. We selected G1.9+0.3 which is the youngest SNR in the Milky Way Galaxy for a study. We compiled the radio flux densities currently available and converted them to the same frequency, which leaves us the evolution of the flux density for the past nearly 50 years. We found that the flux density increased before 2008 and decreased afterwards, meaning the flux density reaching the maximum at an age of about 150–155 yr. We attributed the brightening of the SNR to the increase of either magnetic field or the accelerated high energy electrons. Based on the age at which the flux density reached the peak, combined with the previous numerical simulation, we discussed the ejecta mass of the supernova and kinetic energy released by the supernova explosion.  相似文献   

19.
An account of the theory of the light curves of supernovae is presented, based on certain assumptions concerning the passage through the stellar atmosphere of powerful shock waves. The investigation is based on numerical integration of appropriate equations of gas dynamics and radiative heat-conductivity. The calculations substantially involve the ionization and recombination of hydrogen in the envelope of a supernova. Changes are traced in the curves arising from the transition from compact stars with small radius (10R ), to stars with very extensive envelopes (10000R ). The light curves for compact stars agree well with observations of the peculiar supernovae in NGC 5457, NGC 6946 and NGC 5236. The characteristics of the light curves with the passage of shock waves through the extended atmosphere coincide within an order of magnitude with observations of the supernovae of type II and type I near their maximum brightness. A powerful heat-wave propagates before the shock-front in the extensive atmosphere which gives rise to a detached supernova envelope in the form of a thin spherical layer. We investigated the condition in an ascending wave of cooling and recombination in the supernova envelope. It is shown that part of the hydrogen may recombine to attain full transparency for radiation passing through it. The observations are compared with the results of the theory of radioactive decay of the elements. This explanation of the light curves by the passage of shock waves requires energies of 1050 to 1052 ergs, which are in agreement with mechanisms of thermonuclear explosions.Translated from the Russian by E. Budding.  相似文献   

20.
The most luminous Supernova SN2006gy (more than 100 times brighter than a typical supernova) has been a challenge to explain by standard models. For example, pair-instability supernovae which are luminous enough seem to have too slow a rise, and core-collapse supernovae do not seem to be luminous enough. We present an alternative scenario involving a Quark Nova (an explosive transition of the newly born neutron star to a quark star) in which a second explosion (delayed) occurs inside the ejecta of a normal supernova. The reheated supernova ejecta can radiate at higher levels for longer periods of time primarily due to reduced adiabatic-expansion losses, unlike the standard supernova case. We find an encouraging match between the resulting light curve and that observed in the case of SN2006gy suggesting that we might have at hand the first ever signature of a Quark Nova. Successful application of our model to SN2005gj and SN2005ap is also presented.  相似文献   

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