Astrometry of the 1572 supernova (B Cassiopeiae)

Contemporary European measurements of the Milky Way supernova of 1572 (B Cas) have been analyzed to compute a modern position for the star in 1572. This work adds to that done by previous 20th‐century authors by using a new procedure and previously unused astrometry by 16th‐century European observers. Comparison is made with earlier analyses and to modern positional data on the supernova remnant (3C 10). (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A new look at the position of the 1604 Supernova (V843 Ophiuchi)

The position of the supernova of 1604 (V843 Oph) is re‐assessed, with relevant discussion pertaining to the present‐day remnant, 3C 358. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The dynamic evolution of the Kepler supernova remnant

Two supernovae exploding events were observed visually from the same position, the north of Tian-Jiang in Wei-Suei (the north of 42 Ophiuchi), in 1604 and 1664, respectively, and were recorded in the ancient astronomical literatures of China and Korea. However, in recent years only one supernova remnant (SNR) has been identified in this position using advanced optical, radio and X-ray techniques. Some observed information for the Kepler SNR, including its non-spherically symmetric emission property with brighter north but darker south, have been shown. We conjecture that a supernova outburst in 1664 was excited by the 1604 supernova explosion at a distance of about 0.5 parsecs. The present SNR is formed from the summation of these two explosions. The dynamical evolution of the Kepler SNR is studied by means of a time-dependent, hydrodynamic code in the present paper. The density, velocity, temperature, and X-ray emission distribution of the SNR are shown, being the results of dynamic evolution for 380 years following the explosion of the supernova in 1604. Compared with present radio and X-ray observations, these numerical results may reasonably explain the observational features.     

Supernova SN 1006 in two historic Yemeni reports

We present two Arabic texts of historic observations of supernova SN 1006 from Yemen as reported by al‐Yamānī and Ibn al‐Dayba^c (14th to 16th century AD). An English translation of the report by the latter was given before (Stephenson & Green 2002), but the original Arabic text was not yet published. In addition, we present for the first time the earlier report, also from Yemen, namely by al‐Yamānī in its original Arabic and with our English translation. It is quite obvious that the report by Ibn al‐Dayba^c is based on the report by al‐Yamānī(or a common source), but the earlier report by al‐Yamānī is more detailed and in better (Arabic) language. We discuss in detail the dating of these observations. The most striking difference to other reports about SN 1006 is the apparent early discovery in Yemen in the evening of 15th of Rajab of the year 396h (i.e. AD 1006 April 17±2 on the Julian calendar), as reported by both al‐Yamānī and Ibn al‐Dayba^c, i.e. ∼1.5 weeks earlier than the otherwise earliest known reports. We also briefly discuss other information from the Yemeni reports on brightness, light curve, duration of visibility, location, stationarity, and color. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Masses and luminosities of O‐ and B‐type stars and red supergiants

Massive stars are of interest as progenitors of supernovae, i.e. neutron stars and black holes, which can be sources of gravitational waves. Recent population synthesis models can predict neutron star and gravitational wave observations but deal with a fixed supernova rate or an assumed initial mass function for the population of massive stars. Here we investigate those massive stars, which are supernova progenitors, i.e. with O‐ and early B‐type stars, and also all supergiants within 3 kpc. We restrict our sample to those massive stars detected both in 2MASS and observed by Hipparcos, i.e. only those stars with parallax and precise photometry. To determine the luminosities we calculated the extinctions from published multi‐colour photometry, spectral types, luminosity class, all corrected for multiplicity and recently revised Hipparcos distances. We use luminosities and temperatures to estimate the masses and ages of these stars using different models from different authors. Having estimated the luminosities of all our stars within 3 kpc, in particular for all O‐ and early B‐type stars, we have determined the median and mean luminosities for all spectral types for luminosity classes I, III, and V. Our luminosity values for supergiants deviate from earlier results: Previous work generally overestimates distances and luminosities compared to our data, this is likely due to Hipparcos parallaxes (generally more accurate and larger than previous ground‐based data) and the fact that many massive stars have recently been resolved into multiples of lower masses and luminosities. From luminosities and effective temperatures we derived masses and ages using mass tracks and isochrones from different authors. From masses and ages we estimated lifetimes and derived a lower limit for the supernova rate of ≈20 events/Myr averaged over the next 10 Myr within 600 pc from the sun. These data are then used to search for areas in the sky with higher likelihood for a supernova or gravitational wave event (like OB associations) (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Galilei's astronomical discoveries using the telescope and their evaluation found in a writing‐calendar from 1611

Yearly calendars were a mass‐produced article in early modern times and had an enormous importance in everyday life. Besides a first part, the Calendarium with the monthly tables, they contain a second part, the astrological Prognosticum. At first, the two parts were sold separately. In the second half of the 17th century, the parts were designed as a unity and sold together. The calendars in quart format contain texts which are so interesting that historical research should give them more consideration. Such a text is found, e.g., in the second part of the calendar for 1611, written by Paul Nagel, astronomer and rector of the school in Torgau. Nagel informs about Galilei's discoveries with the telescope. The (Latin) text was written in August 1610. This text is presented and put into perspective in the scientific debates of the time about the telescope as a new invention with consequences to philosophy (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Status of the Connection between Unidentified Egret Sources and Supernova Remnants: The Case of Cta 1

In this paper we briefly comment on the observational status of the possible physical association between unidentified EGRET sources and supernova remnants (SNRs) in our Galaxy. We draw upon recent results presented in the review by Torres et al. (2003), concerning molecular gas in the vicinity of all 19 SNRs found to be positionally coincident with EGRET sources at low Galactic latitudes. In addition, we present new results regarding the supernova remnant CTA 1. Our findings disfavor the possibility of a physical connection with the nearby (in projection) EGRET source. There remains possible, however, that the compact object produced in the supernova explosion be related with the observed γ-ray flux.     

Using X‐ray observations to identify the particle acceleration mechanisms in VHE SNRs and “dark” VHE sources

Very high energy (VHE) γ‐ray observations have proven to be very successful in localizing Galactic acceleration sites of VHE particles. Observations of shell‐type supernova remnants have confirmed that particles are accelerated to VHE energies in supernova blast waves; the interpretation of the γ‐ray data in terms of hadronic or leptonic particle components in these objects relies nevertheless strongly on input from X‐ray observations. The largest identified Galactic VHE source class consists of pulsar wind nebulae, as detected in X‐rays. Many of the remaining VHE sources remain however unidentified until now. With X‐ray observations of these enigmatic “dark” objects one hopes to solve the following questions: What is the astrophysical nature of these sources? Are they predominantly electron or hadron accelerators? And what is their contribution to the overall cosmic ray energy budget? The paper aims to provide an overview over the identification status of the Galactic VHE source population. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Cluster analysis for pattern recognition in solar butterfly diagrams

We investigate to what extent the wings of solar butterfly diagrams can be separated without an explicit usage of Hale's polarity law as well as the location of the solar equator. We apply two algorithms of cluster analysis for this purpose, namely DBSCAN and C‐means, and demonstrate their ability to separate the wings of contemporary butterfly diagrams based on the sunspot group density in the diagram only. Then we apply the method to historical data concerning the solar activity in the 18th century (Staudacher data). The method separates the two wings for Cycle 2, but fails to separate them for Cycle 1. In our opinion, this finding supports the interpretation of the Staudacher data as an indication of the unusual nature of the solar cycle in the 18th century (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The origin of galactic cosmic rays

One century ago Viktor Hess carried out several balloon flights that led him to conclude that the penetrating radiation responsible for the discharge of electroscopes was of extraterrestrial origin. One century from the discovery of this phenomenon seems to be a good time to stop and think about what we have understood about Cosmic Rays. The aim of this review is to illustrate the ideas that have been and are being explored in order to account for the observable quantities related to cosmic rays and to summarize the numerous new pieces of observation that are becoming available. In fact, despite the possible impression that development in this field is somewhat slow, the rate of new discoveries in the last decade or so has been impressive, and mainly driven by beautiful pieces of observation. At the same time scientists in this field have been able to propose new, fascinating ways to investigate particle acceleration inside the sources, making use of multifrequency observations that range from the radio, to the optical, to X-rays and gamma rays. These ideas can now be confronted with data.I will mostly focus on supernova remnants as the most plausible sources of Galactic cosmic rays, and I will review the main aspects of the modern theory of diffusive particle acceleration at supernova remnant shocks, with special attention for the dynamical reaction of accelerated particles on the shock and the phenomenon of magnetic field amplification at the shock. Cosmic-ray escape from the sources is discussed as a necessary step to determine the spectrum of cosmic rays at the Earth. The discussion of these theoretical ideas will always proceed parallel to an account of the data being collected especially in X-ray and gamma-ray astronomy.In the end of this review I will also discuss the phenomenon of cosmic-ray acceleration at shocks propagating in partially ionized media and the implications of this phenomenon in terms of width of the Balmer line emission. This field of research has recently experienced a remarkable growth, in that Hα lines have been found to bear information on the cosmic-ray acceleration efficiency of supernova shocks.     

On the formation of a neutron star in a close binary system

The effects on a close binary system of one component becoming a neutron star as a result of a supernova explosion are discussed in this paper. In the case of a Type I supernova, the system can remain bound in many cases of interest. For a Type II supernova, the system will probably be disrupted although in some cases a remnant of the companion to the supernova may remain in a bound orbit.Consequently, neutron stars formed in Type I supernova explosions may exist in close binary systems. Such systems may be strong X-ray emitters due to mass flow as suggested by Shklovsky. Photons with energies in the 1–50 MeV region should also be emitted.     

Evolution of the Radio Luminosities of the Tycho and Kepler Supernovae Remnants

Radio emission of the historical supernovae remnants Tycho (SNR1572) and Kepler (SNR1604) and evolution of their luminosity are considered. Measurement data of secular luminosity decrease rate, obtained earlier by the authors, were corrected with account of variation in time of the flux density of the reference sources. As a result, it is found that the SNR1604 luminosity at 1667 MHz is weakening with an annual mean rate equal to (0.2 ± 0.07)%. The corresponding rate for SNR1572 is (0.47 ± 0.05)%. Since the radio luminosity evolution, as well as energy densities of magnetic field and relativistic electrons inside SNR1604 and SNR1572 are essentially different, these remnants should be considered as different types of supernovae. Bandiera classified SN1604 as type SNIb or SNII.     

用Monte Carlo方法拟合超新星SN 1993J的早期光谱

通过把从光球辐射出来的连续谱能量分成大量的光子包，然后用MonteCarlo方法跟踪这些光子包从光球向超新星包层外运动的过程，这一方法能很好地解决超新星的光谱拟合中的谱线覆盖问题，由于同时编制了用于构造超新星包层中的密度结构和丰度分布的程序，以及大量的用于比较观测和理论拟合的绘图和支持程序，使我们的MonteCarlo光谱拟合软件包能够很好地运用于超新星的早期光谱研究。本文给出了SN1993J在1993年4月13日的观测光谱的运行实例。     

On the Spörer Minimum

In this paper we have examined the real behaviour of solar activity during the period AD 1400–1600. The results are as follows: (1) the distributions of the 20 naked-eye sunspot records are inhomogeneous. There are 2 sightings in the 15th century and 18 sightings in the 16th century; (2) the distributions of auroral records are similar to sunspot. There are 33 records in the 15th century and 315 records in the 16th century; (3) the climatic fluctuations in China shows that the period AD 1430–1520 was cold while the period AD 1520–1620 was warm. These facts clearly demonstrate that the Spörer Minimum, if it extended from AD 1460 to 1550, could be a specious results and it, if its extent was AD 1400–1510, is a real feature of solar variability in that time.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.     

Sulfur four isotope NanoSIMS analysis of comet‐81P/Wild 2 dust in impact craters on aluminum foil C2037N from NASA’s Stardust mission

Abstract– We present NanoSIMS four‐isotope S analyses of 24 comet Wild 2 dust impact residues in craters on aluminum foil C2037N returned by NASA’s Stardust mission. Except for one sample, all impact residues have normal S isotopic compositions within 2σ uncertainties of at least two S isotope ratios. This implies that most S‐rich Wild 2 dust impactors formed in the solar system. Instrumental isotope fractionation due to sample topography is the main contribution to our analytical uncertainty. One impact crater residue shows small anomalies of δ³³S = ?57 ± 17‰, and δ³⁴S = ?41 ± 17‰ (1σ uncertainties). Although this could be simply a statistical outlier or the fingerprint of a chemical isotope fractionation it is also possible that the observed anomaly results from the mixture of a cometary FeS particle with a small (150 nm diam.) presolar FeS supernova grain. This would translate into a presolar sulfide abundance of approximately 200 ppm.     

A NanoSIMS and Auger Nanoprobe investigation of an isotopically primitive interplanetary dust particle from the 55P/Tempel‐Tuttle targeted stratospheric dust collector

Abstract– An IDP nicknamed Andric, from a stratospheric dust collector targeted to collect dust from comet 55P/Tempel‐Tuttle, contains five distinct presolar silicate and/or oxide grains in 14 ultramicrotome slices analyzed, for an estimated abundance of approximately 700 ppm in this IDP. Three of the grains are ¹⁷O‐enriched and probably formed in low‐mass red giant or asymptotic giant branch (AGB) stars; the other two grains exhibit ¹⁸O enrichments and may have a supernova origin. Carbon and N isotopic analyses show that Andric also exhibits significant variations in its N isotopic composition, with numerous discrete ¹⁵N‐rich hotspots and more diffuse regions that are also isotopically anomalous. Three ¹⁵N‐rich hotspots also have statistically significant ¹³C enrichments. Auger elemental analysis shows that these isotopically anomalous areas consist largely of carbonaceous matter and that the anomalies may be hosted by a variety of components. In addition, there is evidence for dilution of the isotopically heavy components with an isotopically normal endmember; this may have occurred either as a result of extraterrestrial alteration or during atmospheric entry. Isotopically primitive IDPs such as Andric share many characteristics with primitive meteorites such as the CR chondrites, which also contain isotopically anomalous carbonaceous matter and abundant presolar silicate and oxide grains. Although comets are one likely source for the origin of primitive IDPs, the presence of similar characteristics in meteorites thought to come from the asteroid belt suggests that other origins are also possible. Indeed the distinction between cometary and asteroidal sources is somewhat blurred by recent observations of icy comet‐like planetesimals in the outer asteroid belt.     

Charge exchange in massive star‐forming regions

As a result of feedback from massive stars, via their intense winds and/or supernova explosions, massive star‐forming regions are entirely filled with hot, X‐ray emitting plasmas, which escape into the ambient ISM. As shown recently by Townsley et al. for several “extreme” cases (Carina, M17, NGC 3576, NGC 3603, 30 Dor), by way of large Chandra ACIS mosaics, extra, non‐thermal emission lines are present on top of the standard lines emitted by hot plasmas. Some of them are very close to lines characteristic of charge‐exchange reactions between the hot plasma and the cold surrounding material, suggesting that this mechanism operates on large spatial scales (several 10 pc) in star‐forming regions in general. The connection with starburst galaxies is briefly mentioned, and it is pointed out that supernovae interacting with molecular clouds may also provide a good environment to look for charge exchange processes (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Monte‐Carlo simulation of a possible correlation between the estimated luminosity distances and internal extinctions of type Ia supernovae

This paper describes a Monte Carlo simulation of type Ia supernova data. It was shown earlier that the data of SNe Ia might contain a possible correlation between the estimated luminosity distances and internal extinctions. This correlation was shown by different statistical investigations of the data. In order to remove observational biases (for example the effect of the detection limit of the observing instrument) and to test the reality of the effect found earlier we developed a simple routine which simulates extinction values, redshifts and absolute magnitudes for Ia supernovae. We pointed out that the correlation found earlier in the real data between the internal extinction and luminosity distance does not occur in the simulated sample. Furthermore, it became obvious that the detection limit of the observing devices used in supernova projects does not affect the far end of the redshift‐luminosity distance relationship of Ia supernovae. This result strengthens the earlier conclusions of the authors that SN Ia supernovae alone do not support the existence of dark energy. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Object classification at the Nearby Supernova Factory

We present the results of applying new object classification techniques to the supernova search of the Nearby Supernova Factory. In comparison to simple threshold cuts, more sophisticated methods such as boosted decision trees, random forests, and support vector machines provide dramatically better object discrimination: we reduced the number of nonsupernova candidates by a factor of 10 while increasing our supernova identification efficiency. Methods such as these will be crucial for maintaining a reasonable false positive rate in the automated transient alert pipelines of upcoming large optical surveys. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)