We have calculated some properties of spin polarized strange quark matter(SQM) in a strong magnetic field at zero temperature using the MIT bag model.We showed that the equation of state of spin polarized SQM is stiff...We have calculated some properties of spin polarized strange quark matter(SQM) in a strong magnetic field at zero temperature using the MIT bag model.We showed that the equation of state of spin polarized SQM is stiffer than that for unpolarized cases.We have also computed the structural properties of a spin polarized strange quark star(SQS) and found that the presence of a magnetic field leads to a more stable SQS when compared to the structural properties of an unpolarized SQS.展开更多
Fast radio bursts(FRBs) are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron sta...Fast radio bursts(FRBs) are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova- previously thought undetectable when born in isolation- provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star's light cylinder via β-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm^(-3)pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of β-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FRB average energies(~10^(41)erg) and spectral shapes, and provide a theoretical framework for determining distances.展开更多
The accelerated expansion of the Universe was proposed through the use of Type-Ia supernovae(SNe)as standard candles.The standardization depends on an empirical correlation between the stretch/color and peak luminosit...The accelerated expansion of the Universe was proposed through the use of Type-Ia supernovae(SNe)as standard candles.The standardization depends on an empirical correlation between the stretch/color and peak luminosity of the light curves.The use of Type-Ia SNe as standard candles rests on the assumption that their properties(and this correlation)do not vary with redshift.We consider the possibility that the majority of Type-Ia SNe are in fact caused by a Quark-Nova detonation in a tight neutron-star-CO-white-dwarf binary system,which forms a Quark-Nova Ia(QN-Ia).The spin-down energy injected by the Quark-Nova remnant(the quark star)contributes to the post-peak light curve and neatly explains the observed correlation between peak luminosity and light curve shape.We demonstrate that the parameters describing QN-Ia are NOT constant in redshift.Simulated QN-Ia light curves provide a test of the stretch/color correlation by comparing the true distance modulus with that determined using SN light curve fitters.We determine a correction between the true and fitted distance moduli,which when applied to Type-Ia SNe in the Hubble diagram recovers the?M=1 cosmology.We conclude that Type-Ia SNe observations do not necessitate the need for an accelerating expansion of the Universe(if the observed SNe Ia are dominated by QNe Ia)and by association the need for dark energy.展开更多
SN 2006oz is a super-luminous supernova with a mysterious bright precursor that has resisted explanation in standard models.However,such a precursor has been predicted in the dual-shock quark nova model of super-lumin...SN 2006oz is a super-luminous supernova with a mysterious bright precursor that has resisted explanation in standard models.However,such a precursor has been predicted in the dual-shock quark nova model of super-luminous supernovae–the precursor is the supernova event while the main light curve of the super-luminous supernova is powered by the Quark-Nova(explosive transition of the neutron star to a quark star).As the supernova is fading,the Quark-Nova re-energizes the supernova ejecta,producing a"double-humped"light curve.We show that the quark nova model successfully reproduces the observed light curve of SN 2006oz.展开更多
基金supported by the Research Institute for Astronomy and Astrophysics of Maragha
文摘We have calculated some properties of spin polarized strange quark matter(SQM) in a strong magnetic field at zero temperature using the MIT bag model.We showed that the equation of state of spin polarized SQM is stiffer than that for unpolarized cases.We have also computed the structural properties of a spin polarized strange quark star(SQS) and found that the presence of a magnetic field leads to a more stable SQS when compared to the structural properties of an unpolarized SQS.
基金Suooorted by the National Natural Science Foundation of China under Grant No 10573002, and the Key Project of the Ministry of Education of China under Grant No 305001.
文摘Fast radio bursts(FRBs) are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova- previously thought undetectable when born in isolation- provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star's light cylinder via β-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm^(-3)pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of β-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FRB average energies(~10^(41)erg) and spectral shapes, and provide a theoretical framework for determining distances.
文摘The accelerated expansion of the Universe was proposed through the use of Type-Ia supernovae(SNe)as standard candles.The standardization depends on an empirical correlation between the stretch/color and peak luminosity of the light curves.The use of Type-Ia SNe as standard candles rests on the assumption that their properties(and this correlation)do not vary with redshift.We consider the possibility that the majority of Type-Ia SNe are in fact caused by a Quark-Nova detonation in a tight neutron-star-CO-white-dwarf binary system,which forms a Quark-Nova Ia(QN-Ia).The spin-down energy injected by the Quark-Nova remnant(the quark star)contributes to the post-peak light curve and neatly explains the observed correlation between peak luminosity and light curve shape.We demonstrate that the parameters describing QN-Ia are NOT constant in redshift.Simulated QN-Ia light curves provide a test of the stretch/color correlation by comparing the true distance modulus with that determined using SN light curve fitters.We determine a correction between the true and fitted distance moduli,which when applied to Type-Ia SNe in the Hubble diagram recovers the?M=1 cosmology.We conclude that Type-Ia SNe observations do not necessitate the need for an accelerating expansion of the Universe(if the observed SNe Ia are dominated by QNe Ia)and by association the need for dark energy.
基金supported by operating grants from the National Science and Engineering Research Council of Canada (NSERC)
文摘SN 2006oz is a super-luminous supernova with a mysterious bright precursor that has resisted explanation in standard models.However,such a precursor has been predicted in the dual-shock quark nova model of super-luminous supernovae–the precursor is the supernova event while the main light curve of the super-luminous supernova is powered by the Quark-Nova(explosive transition of the neutron star to a quark star).As the supernova is fading,the Quark-Nova re-energizes the supernova ejecta,producing a"double-humped"light curve.We show that the quark nova model successfully reproduces the observed light curve of SN 2006oz.
基金Supported in part by the National Natural Science Foundation of China under Grant Nos 10775069 and 10935001, and the Research Fund for the Doctoral Program of Higher Education under Grant No 200802840009.
