Two Distributions Shedding Light on Type Ia Supernovae Progenitors: Delay Times and G-Dwarf Metallicities (original) (raw)
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The rate of type Ia Supernovae and the Star Formation History
AIP Conference Proceedings, 2009
The scaling of the rate of type Ia Supernovae (SNIa) with the parent galaxies' color provides information on the distribution of the delay times (DTD) of the SNIa progenitors. We show that this information appears to depend on the photometric bands used to trace the stellar age distribution and mass-to-light ratio in the parent galaxies. Using both U − V and B − K colors to constrain the star formation history, we model the SNIa rate as a function of morphological galaxy type for different DTDs. The comparison with the observed rate per unit B and K band luminosity yields consistent results, although the large error bars allow us to exclude only very flat and very narrow DTDs. The number of SNIa events per unit mass from one stellar generation results of ∼ 0.002-0.003 M −1 ⊙ .
Stellar Evolution and the Cosmologial Supernovae Rates
Galaxy Evolution: Connecting the Distant Universe with the Local Fossil Record, 1999
We present the results of the population synthesis of the population of the supernovae progenitors. Both single and double degenerate progenitors of SN Ia are considered. We compute the cosmic rate histories for SN I, SN II and both classes of SN Ia, and present them in the form of redshift and magnitude distributions. These results can be compared with observational data, allowing to estimate the star formation rate history and the cosmological parameters including baryons which cannot be estimated from analysing the Hubble diagrams of supernovae.
Monthly Notices of the Royal Astronomical Society, 2013
We compute the Type Ia supernova rates in typical elliptical galaxies by varying the progenitor models for Type Ia supernovae. To do that a formalism which takes into account the delay distribution function (DTD) of the explosion times and a given star formation history is adopted. Then the chemical evolution for ellipticals with baryonic initial masses 10 10 , 10 11 and 10 12 M ⊙ is computed, and the mass of Fe produced by each galaxy is precisely estimated. We also compute the expected Fe mass ejected by ellipticals in typical galaxy clusters (e.g. Coma and Virgo), under different assumptions about Type Ia SN progenitors. As a last step, we compute the cosmic Type Ia SN rate in an unitary volume of the Universe by adopting several cosmic star formation rates and compare it with the available and recent observational data. Unfortunately, no firm conclusions can be derived only from the cosmic SNIa rate, neither on SNIa progenitors nor on the cosmic star formation rate. Finally, by analysing all our results together, and by taking into account previous chemical evolution results, we try to constrain the best Type Ia progenitor model. We conclude that the best progenitor models for Type Ia SNe are still the single degenerate model, the double degenerate wide model, and the empirical bimodal model. All these models require the existence of prompt Type Ia supernovae, exploding in the first 100 Myr since the beginning of star formation, although their fraction should not exceed 15-20% in order to fit chemical abundances in galaxies.
Rates, progenitors and cosmic mix of Type Ia supernovae
Monthly Notices of the Royal Astronomical Society, 2008
Following an episode of star formation, Type Ia supernova events occur over an extended period of time, following a distribution of delay times (DDT). We critically discuss some empirically based DDT functions that have been proposed in recent years, some favouring very early (prompt) events, other very late (tardy) ones, and therefore being mutually exclusive. We point out that in both the cases the derived DDT functions are affected by dubious assumptions, and therefore there is currently no ground for claiming either a DDT strongly peaked at early times, or at late ones. Theoretical DDT functions are known to accommodate both prompt as well as late SN Ia events, and can account for all available observational constraints. Recent observational evidence exist that both single and double degenerate precursors may be able of producing SN Ia events. We then explore on the basis of plausible theoretical models the possible variation with cosmic time of the mix between the events produced by the two different channels, which, in principle, could lead to systematic effects on the SN Ia properties with redshift.
Delay-Time Distribution of Type-Ia Supernovae: Theory versus Observation
2010
Two formation scenarios are investigated for type Ia supernovae in elliptical galaxies: the single degenerate scenario (a white dwarf reaching the Chandrasekhar limit through accretion of matter transferred from its companion star in a binary) and the double degenerate scenario (the inspiraling and merging of two white dwarfs in a binary as a result of the emission of gravitational wave radiation). A population number synthesis code is used, which includes the latest physical results in binary evolution and allows to differentiate between certain physical scenarios (such as the description of common envelope evolution) and evolutionary parameters (such as the mass transfer efficiency during Roche lobe overflow). The thus obtained theoretical distributions of type Ia supernova delay times are compared to those that are observed, both in morphological shape and absolute number of events. The critical influence of certain parameters on these distributions is used to constrain their values. The single degenerate scenario alone is found to be unable in reproducing the morphological shape of the observational delay time distribution, while use of the double degenerate one (or a combination of both) does result in fair agreement. Most double degenerate type Ia supernovae are formed through a normal, quasi-conservative Roche lobe overflow followed by a common envelope phase, not through two successive common envelope phases as is often assumed. This may cast doubt on the determination of delay times by using analytical formalisms, as is sometimes done in other studies. The theoretical absolute number of events in old elliptical galaxies lies a factor of at least three below the rates that are observed. While this may simply be the result of observational uncertainties, a better treatment of the effects of rotation on stellar structure could mitigate the discrepancy. FIGURE 1. Graphical representation (not to scale) of the two channels typically leading to DD SNe Ia in our population code. Left panel: (conservative) RLOF phase followed by CE phase. Right panel: two successive CE phases.
Type Ia Supernovae: An Examination of Potential Progenitors and the Redshift Distribution
1997
We examine the possibility that supernovae type Ia (SN Ia) are produced by white dwarfs accreting from Roche-lobe filling evolved companions, under the assumption that a strong optically thick stellar wind from accretor is able to stabilize the mass transfer. We show that if a mass transfer phase on a thermal timescale precedes a nuclear burning driven phase, then such systems (of which the supersoft X-ray sources are a subgroup) can account for about 10 % of the inferred SN Ia rate. In addition, we examine the cosmic history of the supernova rate, and we show that the ratio of the rate of SN Ia to the rate of supernovae produced by massive stars (supernovae of types II, Ib, Ic) should increase from about z = 1 towards lower redshifts.
Type-Ia Supernovae: New Clues to their Progenitors from the Delay Time Distribution
2010
Despite their prominent role in cosmography, little is yet known about the nature of type-Ia supernovae (SNe Ia), from the identity of their progenitor systems, through the evolution of those systems up to ignition and explosion, and to the causes of the environmental dependences of their observed properties. I briefly review some of those puzzles. I then focus on recent progress in reconstructing the SN Ia delay time distribution (DTD)-the SN rate versus time that would follow a hypothetical brief burst of star formation. A number of measurements of the DTD over the past two years, using different methods and based on SNe Ia in different environments and redshift ranges, are converging. At delays 1 < t < 10 Gyr, these measurements show a similar ∼ t −1 power-law shape, with similar normalizations. The DTD peaks at the shortest delays probed, but there is still some uncertainty regarding its precise shape in the range 0.1 < t < 1 Gyr. At face value, this result supports Ron Webbinks's (1984) idea of a double-degenerate progenitor origin for SNe Ia, but the numbers currently predicted by binary population synthesis models must be increased by factors of 3-10, at least. Single-degenerate progenitors may still play a role in producing short-delay SNe Ia, or perhaps all SNe Ia, if there are fundamental errors in the current modeling attempts.
The rates of type Ia supernovae
Astronomy & Astrophysics, 2005
The aim of this paper is to provide a handy tool to compute the impact of type Ia SN (SNIa) events on the evolution of stellar systems. An effective formalism to couple the rate of SNIa explosions from a single burst of star formation and the star formation history is presented, which rests upon the definition of the realization probability of the SNIa event (A Ia) and the distribution function of the delay times (f Ia (τ)). It is shown that the current SNIa rate in late type galaxies constrains A Ia to be on the order of 10 −3 (i.e. 1 SNIa every 1000 M of gas turned into stars), while the comparison of the current rates in early and late type galaxies implies that f Ia ought to be more populated at short delays. The paper presents analytical formulations for the description of the f Ia function for the most popular models of SNIa progenitors, namely Single Degenerates (Chandrasekhar and Sub-Chandrasekhar exploders), and Double Degenerates. These formulations follow entirely from general considerations on the evolutionary behavior of stars in binary systems, modulo a schematization of the outcome of the phases of mass exchange, and compare well with the results of population synthesis codes, for the same choice of parameters. The derivation presented here offers an immediate astrophysical interpretation of the shape of the f Ia functions, and have a built in parametrization of the key properties of the alternative candidates. The important parameters appear to be the minimum and maximum masses of the components of the binary systems giving rise to a SNIa explosions, the distribution of the primary mass and of the mass ratios in these systems, the distribution of the separations of the DD systems at their birth. The various models for the progenitors correspond to markedly different impact on the large scales; correspondingly, the model for the progenitor can be constrained by examining the relevant observations. Among these, the paper concentrates on the trend of the current SNIa rate with parent galaxy type. The recent data by Mannucci et al. (2005, A&A, 433, 807) favor the DD channel over the SD one, which tends to predict a too steep distribution function of the delay times. The SD scenario can be reconciled with the observations only if the distribution of the mass ratios in the primordial binaries is flat and the accretion efficiency onto the WD is close to 100%. The various models are characterized by different timescales for the Fe release from a single burst stellar population. In particular the delay time within which half of the SNIa events from such a population have occurred, ranges between 0.3 and 3 Gyr, for a wide variety of hypothesis on the progenitors.
Single and binary evolution of Population III stars and their supernova explosions
Monthly Notices of the Royal Astronomical Society, 2008
We present stellar evolution calculations for Population III stars for both single and binary star evolution. Our models include 10 M⊙ and 16.5 M⊙ single stars and a 10 M⊙ model star that undergoes an episode of accretion resulting in a final mass of 16.1 M⊙. For comparison, we present the evolution of a solar heavy element abundance model. We use the structure from late stage evolution models to calculate simulated supernova light curves. Light curve comparisons are made between accretion and non-accretion progenitor models, and models for single star evolution of comparable masses. Where possible, we make comparisons to previous works. Similar investigations have been carried out, but primarily for solar or near solar heavy metal abundance stars and not including both the evolution and supernovae explosions in one work.
Single and binary evolution of Population III stars and their supernovae explosions
We present stellar evolution calculations for Population III stars for both single and binary star evolution. Our models include 10 M and 16.5 M single stars and a 10 M model star that undergoes an episode of accretion resulting in a final mass of 16.1 M . For comparison, we present the evolution of a solar heavy element abundance model. We use the structure from late stage evolution models to calculate simulated supernova light curves. Light curve comparisons are made between accretion and non-accretion progenitor models, and models for single star evolution of comparable masses. Where possible, we make comparisons to previous works. Similar investigations have been carried out, but primarily for solar or near solar heavy metal abundance stars and not including both the evolution and supernovae explosions in one work.