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1.
We investigate the influence of close neighbor galaxies on the properties of supernovae (SNe) and their host galaxies using 56 SNe located in pairs of galaxies with different levels of star formation (SF) and nuclear activity. The statistical study of SN hosts shows that there is no significant difference between morphologies of hosts in our sample and the larger general sample of SN hosts in the Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8). The mean distance of type II SNe from nuclei of hosts is greater by about a factor of 2 than that of type Ibc SNe. The distributions and mean distances of SNe are consistent with previous results compiled with the larger sample. For the first time it is shown that SNe Ibc are located in pairs with significantly smaller difference of radial velocities between components than pairs containing SNe Ia and II. We consider this as a result of higher star formation rate (SFR) of these closer systems of galaxies. SN types are not correlated with the luminosity ratio of host and neighbor galaxies in pairs. The orientation of SNe with respect to the preferred direction toward neighbor galaxy is found to be isotropic and independent of kinematical properties of the galaxy pair.  相似文献   

2.
The observational cosmology with distant Type Ia supernovae (SNe) as standard candles claims that the Universe is in accelerated expansion, caused by a large fraction of dark energy. In this paper we investigate the SN Ia environment, studying the impact of the nature of their host galaxies on the Hubble diagram fitting. The supernovae (192 SNe) used in the analysis were extracted from Joint-Light-curves-Analysis (JLA) compilation of high-redshift and nearby supernovae which is the best one to date. The analysis is based on the empirical fact that SN Ia luminosities depend on their light curve shapes and colors. We confirm that the stretch parameter of Type Ia supernovae is correlated with the host galaxy type. The supernovae with lower stretch are hosted mainly in elliptical and lenticular galaxies. No significant correlation between SN Ia colour and host morphology was found. We also examine how the luminosities of SNe Ia change depending on host galaxy morphology after stretch and colour corrections. Our results show that in old stellar populations and low dust environments, the supernovae are slightly fainter. SNe Ia in elliptical and lenticular galaxies have a higher α (slope in luminosity-stretch) and β (slope in luminosity-colour) parameter than in spirals. However, the observed shift is at the 1-σ uncertainty level and, therefore, can not be considered as significant. We confirm that the supernova properties depend on their environment and that the incorporation of a host galaxy term into the Hubble diagram fit is expected to be crucial for future cosmological analyses.  相似文献   

3.
We investigate the history of galactic feedback and chemical enrichment within a sample of 15 X-ray bright groups of galaxies, on the basis of the inferred Fe and Si distributions in the hot gas and the associated metal masses produced by core-collapse and Type Ia supernovae (SNe). Most of these cool-core groups show a central Fe and Si excess, which can be explained by prolonged enrichment by SN Ia and stellar winds in the central early-type galaxy alone, but with tentative evidence for additional processes contributing to core enrichment in hotter groups. Inferred metal mass-to-light ratios inside r 500 show a positive correlation with total group mass but are generally significantly lower than in clusters, due to a combination of lower global intracluster medium (ICM) abundances and gas-to-light ratios in groups. This metal deficiency is present for products from both SN Ia and SN II, and suggests that metals were either synthesized, released from galaxies or retained within the ICM less efficiently in lower mass systems. We explore possible causes, including variations in galaxy formation and metal release efficiency, cooling out of metals, and gas and metal loss via active galactic nuclei (AGN) – or starburst-driven galactic winds from groups or their precursor filaments. Loss of enriched material from filaments coupled with post-collapse AGN feedback emerges as viable explanations, but we also find evidence for metals to have been released less efficiently from galaxies in cooler groups and for the ICM in these to appear chemically less evolved, possibly reflecting more extended star formation histories in less massive systems. Some implications for the hierarchical growth of clusters from groups are briefly discussed.  相似文献   

4.
Employing Eggleton’s stellar evolution code with the optically thick wind assumption, we have systematically studied the WD + He star channel of Type Ia supernovae (SNe Ia), in which a carbon–oxygen WD accretes material from a He main-sequence star or a He subgiant to increase its mass to the Chandrasekhar mass. We mapped out the parameter spaces for producing SNe Ia. According to a detailed binary population synthesis approach, we find that the Galactic SN Ia birthrate from this channel is ～0.3×10?3 yr?1, and that this channel can produce SNe Ia with short delay times (～45–140 Myr). We also find that the surviving companion stars in this channel have a high spatial velocity (>400 km/s) after the SN explosion, which could be an alternative origin for hypervelocity stars (HVSs), especially for HVSs such as US 708.  相似文献   

5.
Type Ia supernovae (SNe Ia) play an important role in astrophysics and are crucial for the studies of stellar evolution, galaxy evolution and cosmology. They are generally thought to be thermonuclear explosions of accreting carbon–oxygen white dwarfs (CO WDs) in close binaries, however, the nature of the mass donor star is still unclear. In this article, we review various progenitor models proposed in the past years and summarize many observational results that can be used to put constraints on the nature of their progenitors. We also discuss the origin of SN Ia diversity and the impacts of SN Ia progenitors on some fields. The currently favourable progenitor model is the single-degenerate (SD) model, in which the WD accretes material from a non-degenerate companion star. This model may explain the similarities of most SNe Ia. It has long been argued that the double-degenerate (DD) model, which involves the merger of two CO WDs, may lead to an accretion-induced collapse rather than a thermonuclear explosion. However, recent observations of a few SNe Ia seem to support the DD model, and this model can produce normal SN Ia explosion under certain conditions. Additionally, the sub-luminous SNe Ia may be explained by the sub-Chandrasekhar mass model. At present, it seems likely that more than one progenitor model, including some variants of the SD and DD models, may be required to explain the observed diversity of SNe Ia.  相似文献   

6.
Type Ia supernovae(SNe Ia) play an important role in studies of cosmology and galactic chemical evolution.They are believed to be thermonuclear explosions of carbon-oxygen white dwarfs(CO WDs)when their masses approach the Chandrasekar(Ch) mass limit.However,it is still not completely understood how a CO WD increases its mass to the Ch-mass limit in the classical single-degenerate(SD) model.In this paper,we studied the mass accretion process in the SD model to examine whether the WD can explode as an SN Ia.Employing the stellar evolution code called modules for experiments in stellar astrophysics(MESA),we simulated the He accretion process onto CO WDs.We found that the WD can increase its mass to the Ch-mass limit through the SD model and explosive carbon ignition finally occurs in its center,which will lead to an SN Ia explosion.Our results imply that SNe Ia can be produced from the SD model through steady helium accretion.Moreover,this work can provide initial input parameters for explosion models of SNe Ia.  相似文献   

7.
The time delay between the formation of the progenitor systems of Type Ia supernovae (SNe Ia) and their detonation is a vital discriminant between the various progenitor scenarios that have been proposed for them. We use Sloan Digital Sky Survey optical and Galaxy Evolution Explorer ( GALEX ) ultraviolet observations of the early-type host galaxies of 21 nearby SNe Ia and quantify the presence or absence of any young stellar population to constrain the minimum time delay for each supernova. We find that early-type host galaxies lack 'prompt' SNe Ia with time delays of ≲100 Myr and that ∼70 per cent SNe Ia have minimum time delays of 275 Myr–1.25 Gyr, with a median of 650 Myr, while at least 20 per cent SNe Ia have minimum time delays of at least 1 Gyr at 95 per cent confidence and two of these four SNe Ia are likely older than 2 Gyr. The distribution of minimum time delays observed matches most closely the expectation for the single-degenerate channel with a main sequence donor. Furthermore, we do not find any evidence that subluminous SNe Ia are associated with long time delays.  相似文献   

8.
Using Hurley's rapid binary stellar evolution code, we have studied the model-synthesized rate of Type la Supernovae (SNe Ia) and its influence on the chemical enrichment of the interstellar medium ejected by stellar populations. We adopt two popular scenarios, i.e.,single degenerate scenario (SD) and double degenerate scenario (DD), for the progenitors of SNe Ia to calculate the rates of SNe Ia. Rates calculated in this work agree with that of Hachisu et al. and Han & Podsiadlowski, but are different from that usually adopted in chem-ical evolution models of galaxies. We apply the rates of SNe Ia to the chemical enrichment (especially Fe enrichment), then compare the results with previous studies. As known SNe Ia slightly affect the enrichment of C, N, O and Mg elements, while significantly affect the en-richment of Fe. We find that the occurrence and the value of the Fe enrichment in our models are earlier and smaller than that commonly adopted in chemical evolution models. We also study the evolution of [Mg/Fe] ratios, which are almost reciprocals of the Fe enrichment.The study may provide constraints on the free parameters of chemical evolution models of galaxies and evolutionary population synthesis.  相似文献   

9.
The helium star donor channel for the progenitors of Type Ia supernovae   总被引：1，自引：0，他引：1  
  相似文献   

10.
GAIA is the 'super- Hipparcos ' satellite scheduled for launch in 2010 by the European Space Agency. It is a scanning satellite that carries out multi-colour, multi-epoch photometry on all objects brighter than 20th mag. We conduct detailed simulations of supernovae (SNe) detection by GAIA . Supernovae of each type are chosen according to the observed distributions of absolute magnitudes, and located in nearby galaxies according to the local large-scale structure. Using an extinction model of the Galaxy and the scanning law of the GAIA satellite, we calculate how many SNe are detectable as a function of the phase of the light curve. Our study shows that GAIA will report data on ∼21 400 SNe during the five-year mission lifetime, of which ∼14 300 are SNe Ia, ∼1400 are SNe Ib/c and ∼5700 are SNe II. Using the simulations, we estimate that the numbers caught before maximum are ∼6300 SNe Ia, ∼500 SNe Ib/c and ∼1700 SNe II. During the mission lifetime, GAIA will issue about 5 SNe alerts a day.
The most distant SNe accessible to GAIA are at a redshift   z ∼ 0.14  and so GAIA will provide a huge sample of local SNe. There will be many examples of the rarer subluminous events, over-luminous events, SNe Ib/c and SNe II-L. SNe rates will be found as a function of galaxy type, as well as extinction and position in the host galaxy. Amongst other applications, there may be about 26 SNe each year for which detection of gravitational waves is possible and about 180 SNe each year for which detection of gamma-rays is possible. GAIA 's astrometry will provide the SN position to better than milliarcseconds, offering opportunities for the identification of progenitors in nearby galaxies and for studying the spatial distribution of SNe of different types in galaxies.  相似文献   

11.
HD49798 is a hydrogen depleted subdwarf 06 star and has an X-ray pulsating companion(RX J0648.0-4418).The X-ray pulsating companion is a massive white dwarf.Employing Eggleton's stellar evolution code with the optically thick wind assumption,we find that the hot subdwarf HD 49798 and its X-ray pulsating companion could produce a type Ia supernova(SN Ia)in future evolution.This implies that the binary system is a likely candidate of an SN Ia progenitor.We also discuss the possibilities of some other WD+He star systems(e.g.V445 Pup and KPD1930+2752)for producing SNe Ia.  相似文献   

12.
In the chemical evolution of the Galaxy, Type II supernovae (SNe II)have contributed to the early metal enrichment and later Type Iasupernovae (SNe Ia) have contributed to the delayed enrichment of Fe.In principle, hypothetical pre-galactic population III objects couldcause the earliest heavy element enrichment. Here we present our twonew findings. 1) The peculiar abundance pattern among iron peakelements (Cr, Mn, Co, and Fe) in the very metal poor can be reproducedwith SN II nucleosynthesis yields without invoking the contributionfrom Pop III objects. 2) The observed chemical evolution in the solarneighborhood is well reproduced with the metallicity dependentoccurrence of SNe Ia, where SNe Ia do not occur if the iron abundanceof the progenitors is as low as [Fe/H] ≲ -1. We make theprediction that the cosmic SN Ia rate drops at z ∼ 1-2 because ofthe low-iron abundance, which can be observed with the Next GenerationSpace Telescope. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

13.
In order to investigate the influence of environment on supernova (SN) production, we have performed a statistical investigation of the SNe discovered in isolated galaxies, in pairs and in groups of galaxies. 22 SNe in 18 isolated galaxies, 48 SNe in 40 galaxy members of 37 pairs and 211 SNe in 170 galaxy members of 116 groups have been selected and studied.
We found that the radial distributions of core-collapse SNe in galaxies located in different environments are similar, and consistent with those reported by Bartunov, Makarova & Tsvetkov . SNe discovered in pairs do not favour a particular direction with respect to the companion galaxy. Also, the azimuthal distributions inside the host members of galaxy groups are consistent with being isotropics. The fact that SNe are more frequent in the brighter components of the pairs and groups is expected from the dependence of the SN rates on the galaxy luminosity.
There is an indication that the SN rate is higher in galaxy pairs compared with that in groups. This can be related to the enhanced star formation rate in strongly interacting systems.
It is concluded that, with the possible exception of strongly interacting systems, the parent galaxy environment has no direct influence on SN production.  相似文献   

14.
The host galaxies of active galactic nuclei   总被引：2，自引：0，他引：2  
We examine the properties of the host galaxies of 22 623 narrow-line active galactic nuclei (AGN) with  0.02 < z < 0.3  selected from a complete sample of 122 808 galaxies from the Sloan Digital Sky Survey. We focus on the luminosity of the [O  iii ]λ5007 emission line as a tracer of the strength of activity in the nucleus. We study how AGN host properties compare with those of normal galaxies and how they depend on L [O  iii ]. We find that AGN of all luminosities reside almost exclusively in massive galaxies and have distributions of sizes, stellar surface mass densities and concentrations that are similar to those of ordinary early-type galaxies in our sample. The host galaxies of low-luminosity AGN have stellar populations similar to normal early types. The hosts of high-luminosity AGN have much younger mean stellar ages. The young stars are not preferentially located near the nucleus of the galaxy, but are spread out over scales of at least several kiloparsecs. A significant fraction of high-luminosity AGN have strong Hδ absorption-line equivalent widths, indicating that they experienced a burst of star formation in the recent past. We have also examined the stellar populations of the host galaxies of a sample of broad-line AGN. We conclude that there is no significant difference in stellar content between type 2 Seyfert hosts and quasars (QSOs) with the same [O  iii ] luminosity and redshift. This establishes that a young stellar population is a general property of AGN with high [O  iii ] luminosities.  相似文献   

15.
The distributions of supernovae of different types and subtypes along the radius and in z coordinate of galaxies have been studied. We show that among the type Ia supernovae (SNe Ia) in spiral galaxies, SNe Iax and Ia-norm have, respectively, the largest and smallest concentration to the center; the distributions of SNe Ia-91bg and Ia-91T are similar. A strong concentration of SNe Ib/c to the central regions has been confirmed. In spiral galaxies, the supernovae of all types strongly concentrate to the galactic plane; the slight differences in scale height correlate with the extent to which the classes of supernovae are associated with star formation.  相似文献   

16.
Using three-dimensional hydrodynamical simulations of isolated dwarf spheroidal galaxies (dSphs), we undertake an analysis of the chemical properties of their inner regions, identifying the respective roles played by Type Ia supernovae (SNe Ia) and Type II supernovae (SNe II). The effect of inhomogeneous pollution from SNe Ia is shown to be prominent within two core radii, with the stars forming therein amounting to ∼20 per cent of the total. These stars are relatively iron-rich and α-element depleted compared to the stars forming in the rest of the galaxy. At odds with the projected stellar velocity dispersion radial profile, the actual three-dimensional one shows a depression in the central region, where the most metal-rich (i.e. [Fe/H]-rich) stars are partly segregated. This naturally results in two different stellar populations, with an anticorrelation between [Fe/H] and velocity dispersion, in the same sense as that observed in the Sculptor and Fornax dSphs. Because the most iron-rich stars in our model are also the most α depleted, a natural prediction and test of our model is that the same radial segregation effects should exist between [α/Fe] and velocity dispersion.  相似文献   

17.
We have observed the largest optical spectra sample of 97 blue compact galaxies. Stellar population properties of 74 star-forming BCGs of them were derived by comparing the equivalent widths of strong absorption features and continuum colors, using a method of empirical population synthesis based on star cluster sample. The results indicate that blue compact galaxies are typically age-composite stellar system, the continuum flux fractions at 5870Å due to old stellar components and young stellar components are both important for most of the galaxies. The stellar populations of blue compact galaxies present a variety of characteristics, and the contribution from different age and metallicity components is different. The star formation episodes are usually short, some galaxies maybe undergoing their first global episode of star formation, while for the most sample galaxies, older stars contribute to at most half the optical emission. Our results suggest that BCGs are old galaxies, in which star formation occurs in short intense burst separated by long quiescent phases.  相似文献   

18.
首先利用Ａｓｉａｇｏ 超新星星表对Ｉａ 超新星作了统计分析。其次用具有精确测光的Ｉａ 超新星对其均匀性及多样性进行了研究。旋涡星系中Ｉａ 超新星的产生率比椭圆星系的要高。最亮的Ｉａ 超新星只出现于晚型旋涡星系中;而旋涡星系及早型的椭圆星系都是暗Ｉａ 超新星的寄主星系。离星系中心越近Ｉａ 超新星的光度弥散有增加的趋势,但这一趋势对蓝Ｉａ 超新星不明显。利用色指数可将Ｉａ 超新星划分为蓝超新星及红超新星。蓝Ｉａ 超新星构成了相对均匀的Ｉａ 超新星样本,是较好的距离指示器;而红Ｉａ 超新星的存在则表明了Ｉａ 超新星整体多样性的特点。最后,我们还探讨了Ｉａ 超新星中碳点火的非线性问题。  相似文献   

19.
Type Ia Supernova (SN Ia) are a powerful, albeit not completely understood, tool for cosmology. Gaps in our understanding of their progenitors and detailed physics can lead to systematic errors in the cosmological distances they measure. We use UV data in two context to help further our understanding of SN Ia progenitors and physics. We analyze a set of nearly 700 light curves, and find no signature of the shock heating of a red giant companion, predicted by Kasen (Astrophys. J. 708:1025, 2010), casting doubt as to frequency of this SN Ia channel. We also use UV imaging of high redshift host galaxies of SN Ia to better understand the environments which SN Ia occur. We show that some high-z elliptical galaxies have current star formation, hindering efforts to use them as low-extinction environments. We show cosmological scatter of SN distances at large effective radii in their hosts is significantly reduced, and argue this is due to the smaller amounts of dust affecting the SN Ia. Finally, we find a two component dependence of SN distance measurements as a function of their host galaxy’s FUV-V color. This indicates that both the age and metallicity/mass of the host galaxy maybe important ingredients in measuring SN Ia distances.  相似文献   

20.
By assuming an aspherical stellar wind with an equatorial disc from a red giant, we investigate the production of Type Ia supernovae (SNe Ia) via a symbiotic channel. We estimate that the Galactic birthrate of SNe Ia via the symbiotic channel is between  1.03 × 10−3  and  2.27 × 10−5 yr−1  , while the delay time of SNe Ia has a wide range from ∼0.07 to 5 Gyr. The results are greatly affected by the outflow velocity and mass-loss rate of the equatorial disc. Using our model, we discuss the progenitors of SN 2002ic and SN 2006X.  相似文献   

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