Download or read book Low Mass SN Ia and the Late Light Curve written by Stirling A. Colgate and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low Mass SN Ia and the Late Light Curve written by and published by . This book was released on 1995 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: The late bolometric light curves of type Ia supernovae, when measured accurately over several years, show an exponential decay with a 56d half-life over a drop in luminosity of 8 magnitudes (10 half-lives). The late-time light curve is thought to be governed by the decay of Co56, whose 77d half-life must then be modified to account for the observed decay time. Two mechanisms, both relying upon the positron fraction of the Co56 decay, have been proposed to explain this modification. One explanation requires a large amount of emission at infra-red wavelengths where it would not be detected. The other explanation has proposed a progressive transparency or leakage of the high energy positrons (Colgate, Petschek and Kriese, 1980). For the positrons to leak out of the expanding nebula at the required rate necessary to produce the modified 56d exponential, the mass of the ejecta from a one foe (1051 erg in kinetic energy) explosion must be small, M{sub ejec} = 0.4M{sub {circle_dot}} with M{sub ejec} (proportional to) KE{sup 0.5}. Thus, in this leakage explanation, any reasonable estimate of the total energy of the explosion requires that the ejected mass be very much less than the Chandrasekhar mass of 1.4M{sub {circle_dot}}. This is very difficult to explain with the ''canonical'' Chandrasekhar-mass thermonuclear explosion that disintegrates the original white dwarf star. This result leads us to pursue alternate mechanisms of type Ia supernovae. These mechanisms include sub-Chandrasekhar thermonuclear explosions and the accretion induced collapse of Chandrasekhar mass white dwarfs. We will summarize the advantages and disadvantages of both mechanisms with considerable detail spent on our new accretion induced collapse simulations. These mechanisms lead to lower Ni56 production and hence result in type Ia supernovae with luminosities decreased down to (approximately) 50% that predicted by the ''standard'' model.
Download or read book Thermonuclear Supernovae written by P. Ruiz-Lapuente and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 891 pages. Available in PDF, EPUB and Kindle. Book excerpt: All theoretical and observational topics relevant to the understanding of the thermonuclear (Type Ia) supernova phenomenon are thoroughly and consistently reviewed by a panel including the foremost experts in the field. The book covers all aspects, ranging from the observations of SNe Ia at all stages and all wavelengths to the 2D and 3D modelling of thermonuclear flames in very dense plasmas. Scenarios for close binary evolution leading to SNe Ia are discussed. Particular emphasis is placed on the homogeneity vs. diversity of SNe Ia and on their use as standard candles to measure cosmological parameters. The book reflects the recent and very significant progress made in both the modelling of the explosions and in the observational field.
Download or read book Handbook of Supernovae written by Athem W. Alsabti and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectral Observations and Analyses of Low Redshift Type Ia Supernovae written by Jeffrey Michael Silverman and published by . This book was released on 2011 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt: The explosive deaths of stars, known as a supernovae (SNe), have been critical to our understanding of the Universe for centuries. From the first evidence of a changing Universe beyond the Moon (Brahe1573) to the first evidence of the accelerating expansion of the Universe (Riess et al. 1998; Perlmutter et al. 1999), SNe - and often a specific subclass of SNe called Type Ia SNe (SNe Ia) - have been integral to astronomical research. An introduction to SNe, their importance in astronomy, and how we observe them is given in Chapter 1. How SNe Ia explode, what progenitor systems give rise to them, and how different initial conditions affect the observed outcomes of these objects are understood only at a relatively basic level. In other words, a detailed understanding of the physics behind SNe Ia is still lacking. One way astronomers can begin to solve these problems, and others involving SNe Ia, is to obtain and analyze a large, self-consistent dataset of SN Ia observations. This is the goal of the Berkeley SN Ia Program (BSNIP) which comprises the majority of this Thesis. In the second Chapter, I present the full BSNIP sample which consists of 1298 low-redshift (z greater than or equal to 0.2) optical spectra of 582 SNe Ia observed from 1989 through the end of 2008. Many of the SNe have well-calibrated light curves with measured distances as well as spectra which have been corrected for host-galaxy contamination. Most of the data were obtained using the Kast double spectrograph mounted on the Shane 3 m telescope at Lick Observatory with typical wavelength coverage of 3300-10400 A, which is significantly larger than that of most previously published SN Ia spectral datasets. I also present the BSNIP observing and reduction procedures used during the two decades over which the data were collected. In addition, I describe our spectral classification scheme (using the SuperNova IDentification code, SNID; Blondin & Tonry 2007), utilizing my newly constructed set of SNID spectral templates. These templates allow me to accurately spectroscopically classify the entire BSNIP dataset, and by doing so I am able to reclassify a handful of objects as bona fide SNe Ia and a few other objects as members of some of the peculiar SN Ia subtypes. In fact, the BSNIP dataset includes spectra of nearly 90 spectroscopically peculiar SNe Ia. I also present spectroscopic host-galaxy redshifts of some SNe Ia where these values were previously unknown. The sheer size of the BSNIP dataset and the consistency of the observation and reduction methods makes this sample unique among all other published SN Ia datasets and is complementary in many ways to the large, low-redshift SN Ia spectra presented by Matheson et al. 2008 and Blondin et al. 2011. I present measurements of spectral features of 432 low-redshift (z z x1 and c) and spectral measurements to calculate distance moduli. The residuals from these models is then compared to the standard model which only uses light-curve stretch and color. The pEW of Si II lamda 4000 is found to be a good indicator of light-curve width and the pEWs of the Mg II and Fe II complexes are relatively good proxies for color. However, a distance model only using these spectroscopic measurements performs worse than the standard model which uses only light-curve parameters. When using a distance model which combines the ratio of fluxes near 3̃600 A and 4̃300 A with both x1 and c, the Hubble residuals are decreased by 12%, which is found to be significant at the 2.4 omega level. The weighted root-mean square of the residuals using this model is 0.130 plus or minus 0.019 mag (as compared to 0.146 plus or minus 0.019 mag when using the same sample with the standard model). This Hubble diagram fit has one of the smallest scatters ever published and at the highest significance ever seen in such a study. Finally, these results are discussed with regard to how they can improve the cosmological accuracy of future, large-scale SN Ia surveys. Finally, I conclude this Thesis with an in-depth study of a quite peculiar SN Ia, not included in the BSNIP sample. Chapter 5 presents and analyzes optical photometry and spectra of the extremely luminous and slowly evolving Type Ia SN 2009dc, and offers evidence that it is a super-Chandrasekhar mass (SC) SN Ia and thus had a SC white dwarf (WD) progenitor. Optical spectra of SN 2007if, a similar object, are also shown. SN 2009dc had one of the most slowly evolving light curves ever observed for a SN Ia, with a rise time of 2̃3 d and delta m15(B) = 0.72 mag. I calculate a lower limit to the peak bolometric luminosity of 2̃.4x1043 erg s-1, though the actual value is likely almost 40% larger. Optical spectra of SNe 2009dc and 2007if obtained near maximum brightness exhibit strong C II features (indicative of a significant amount of unburned material), and the post-maximum spectra are dominated by iron-group elements. All of the spectra of SNe 2009dc and 2007if also show low expansion velocities. However, I see no strong evidence in SN 2009dc for a velocity "plateau" near maximum light like the one seen in SN 2007if (Scalzo et al. 2010). The high luminosity and low expansion velocities of SN 2009dc lead to a derived WD progenitor mass of more than 2 MSun and a 56Ni mass of about 1.4-1.7 MSun. I propose that the host galaxy of SN 2009dc underwent a gravitational interaction with a neighboring galaxy in the relatively recent past. This may have led to a sudden burst of star formation which could have produced the SC WD progenitor of SN 2009dc and likely turned the neighboring galaxy into a "post-starburst galaxy." No published model seems to match the extreme values observed in SN 2009dc, but simulations do show that such massive progenitors can exist (likely as a result of the merger of two WDs) and can possibly explode as SC SNe Ia.
Download or read book Supernovae and Nucleosynthesis written by David Arnett and published by Princeton University Press. This book was released on 2020-11-10 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book investigates the question of how matter has evolved since its origin in the Big Bang, from the cosmological synthesis of hydrogen and helium to the generation of the complex set of nuclei that comprise our world and our selves. A central theme is the evolution of gravitationally contained thermonuclear reactors, otherwise known as stars. Our current understanding is presented systematically and quantitatively, by combining simple analytic models with new state-of-the-art computer simulations. The narrative begins with the clues (primarily the solar system abundance pattern), the constraining physics (primarily nuclear and particle physics), and the thermonuclear burning in the Big Bang itself. It continues with a step-by-step description of how stars evolve by nuclear reactions, a critical investigation of supernova explosion mechanisms and the formation of neutron stars and of black holes, and an analysis of how such explosions appear to astronomers (illustrated by comparison with recent observations). It concludes with a synthesis of these ideas for galactic evolution, with implications for nucleosynthesis in the first generation of stars and for the solar system abundance pattern. Emphasis is given to questions that remain open, and to active research areas that bridge the disciplines of astronomy, cosmochemistry, physics, and planetary and space science. Extensive references are given.
Download or read book Type Ia Supernovae written by Jens C. Niemeyer and published by Cambridge University Press. This book was released on 2000-05 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: A unique and wide-ranging review of one of the most dramatic research results in astronomy in recent decades.
Download or read book Thermonuclear Supernovae written by P. Ruiz-Lapuente and published by Springer Science & Business Media. This book was released on 1997 with total page 920 pages. Available in PDF, EPUB and Kindle. Book excerpt: All theoretical and observational topics relevant to the understanding of the thermonuclear (Type Ia) supernova phenomenon are thoroughly and consistently reviewed by a panel including the foremost experts in the field. The book covers all aspects, ranging from the observations of SNe Ia at all stages and all wavelengths to the 2D and 3D modelling of thermonuclear flames in very dense plasmas. Scenarios for close binary evolution leading to SNe Ia are discussed. Particular emphasis is placed on the homogeneity vs. diversity of SNe Ia and on their use as standard candles to measure cosmological parameters. The book reflects the recent and very significant progress made in both the modelling of the explosions and in the observational field.
Download or read book Astrophysik IV Sternsysteme Astrophysics IV Stellar Systems written by Frank K. Edmonson and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 573 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Early Universe and Observational Cosmology written by Nora Bretón and published by Springer Science & Business Media. This book was released on 2004-05-14 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spectacular experimental advances in observational cosmology have helped raise cosmology to the status of a genuine science, and it is now possible to test many speculative theoretical issues and to obtain reliable values for the key parameters defining our observable universe. This book has emerged from selected lectures given at the Mexican School on Gravitation and Mathematical Physics by leaders in their field. Conceived as both a broad survey and as topical coverage of the latest developments, it will benefit graduate students and newcomers to this field and provide researchers in the field with a modern source of reference.
Download or read book Supernovae And Stellar Evolution Proceedings Of The School And Workshop written by A Ray and published by World Scientific. This book was released on 1991-05-24 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers in this volume present a recent survey of important results in the field of supernovae and pulsars. The review articles are likely to prove valuable because of their pedagogical nature to students and other entrants in the field. For researchers already working in this field, observational results and the details of theoretical investigations presented systematically are likely to stimulate further debates regarding classification of supernovae types Ia Ib and II and their progenitors and their relationship. New results are presented.
Download or read book Physics of Binary Star Evolution written by Thomas M Tauris and published by Princeton University Press. This book was released on 2023-03-28 with total page 865 pages. Available in PDF, EPUB and Kindle. Book excerpt: A graduate-level textbook on the astrophysics of binary star systems and their evolution Physics of Binary Star Evolution is an up-to-date textbook on the astrophysics and evolution of binary star systems. Theoretical astrophysicists Thomas Tauris and Edward van den Heuvel cover a wide range of phenomena and processes, including mass transfer and ejection, common envelopes, novae and supernovae, X-ray binaries, millisecond radio pulsars, and gravitational wave (GW) sources, and their links to stellar evolution. The authors walk through the observed properties and evolution of different types of binaries, with special emphasis on those containing compact objects (neutron stars, black holes, and white dwarfs). Attention is given to the formation mechanisms of GW sources—merging double neutron stars and black holes as well as ultra-compact GW binaries hosting white dwarfs—and to the progenitors of these sources and how they are observed with radio telescopes, X-ray satellites, and GW detectors (LIGO, Virgo, KAGRA, Einstein Telescope, Cosmic Explorer, and LISA). Supported by illustrations, equations, and exercises, Physics of Binary Star Evolution combines theory and observations to guide readers through the wonders of a field that will play a central role in modern astrophysics for decades to come. 465 equations, 47 tables, and 350+ figures More than 80 exercises (analytical, numerical, and computational) Over 2,500 extensive, up-to-date references
Download or read book Supernovae and Supernova Remnants written by International Astronomical Union. Colloquium and published by Cambridge University Press. This book was released on 1996-03-21 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive and timely review of studies of supernovae and supernova remnants.
Download or read book Supernovae and Stellar Wind in the Interstellar Medium written by Tatjana A. Lozinskaya and published by Springer Science & Business Media. This book was released on 1991-11-01 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: A leading stellar astronomer summarizes our understanding of supernovae and their interaction with interstellar gas, including the ambient interstellar medium, the gas ejected in the explosion itself, and the gas emitted as stellar wind. She examines the evolution of supernova remnants as they interact with the gas and considers the role of supernovae and stellar wind in the physical state of the interstellar medium. Essential reading for specialists in supernovae and stellar evolution.
Download or read book Supernova Explosions written by David Branch and published by Springer. This book was released on 2017-08-02 with total page 719 pages. Available in PDF, EPUB and Kindle. Book excerpt: Targeting advanced students of astronomy and physics, as well as astronomers and physicists contemplating research on supernovae or related fields, David Branch and J. Craig Wheeler offer a modern account of the nature, causes and consequences of supernovae, as well as of issues that remain to be resolved. Owing especially to (1) the appearance of supernova 1987A in the nearby Large Magellanic Cloud, (2) the spectacularly successful use of supernovae as distance indicators for cosmology, (3) the association of some supernovae with the enigmatic cosmic gamma-ray bursts, and (4) the discovery of a class of superluminous supernovae, the pace of supernova research has been increasing sharply. This monograph serves as a broad survey of modern supernova research and a guide to the current literature. The book’s emphasis is on the explosive phases of supernovae. Part 1 is devoted to a survey of the kinds of observations that inform us about supernovae, some basic interpretations of such data, and an overview of the evolution of stars that brings them to an explosive endpoint. Part 2 goes into more detail on core-collapse and superluminous events: which kinds of stars produce them, and how do they do it? Part 3 is concerned with the stellar progenitors and explosion mechanisms of thermonuclear (Type Ia) supernovae. Part 4 is about consequences of supernovae and some applications to astrophysics and cosmology. References are provided in sufficient number to help the reader enter the literature.
Download or read book Massive Stars written by Space Telescope Science Institute (U.S.). Symposium and published by Cambridge University Press. This book was released on 2009-11-12 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents observational and theoretical papers from world experts addressing the important role in astrophysics of massive stars.
Download or read book Bridging the Gap written by Mansi M. Kasliwal and published by Universal-Publishers. This book was released on 2012 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: For centuries, we have known that our dynamic universe is adorned by cosmic fireworks: energetic and ephemeral beacons of light from a single star that are a million (nova) to a billion (supernova) times brighter than our sun. However, it had been an age-old conundrum that the brightest nova is approximately 1000 times fainter than the faintest supernova; why should nature leave such a wide "gap"? In search of an answer, I undertook three systematic surveys for my thesis. Since I was looking for transients fainter, faster and rarer than supernovae, I focused my search on galaxies in the local universe. We now have convincing evidence of multiple, distinct populations of rare transients bridging this "gap." Perhaps, we are witnessing new stellar physics- shell detonations in ultra-compact white dwarf binaries, electron-capture supernovae, white dwarfs collapsing into neutron stars and birth of black-holes. A small number of intensively followed-up discoveries of elusive transients sets the stage for population studies with the upcoming "Large Synoptic Survey Telescope." This effort works towards building a complete inventory of transients in the local universe (d
