arXiv subjects

Carles Badenes

Publications and source records attributed to Carles Badenes.

126 records · Page 7Linked to original sources

arXiv2009

Twins: The Two Shortest Period Non-Interacting Double Degenerate White Dwarf Stars

We report on the detection of the two shortest period non-interacting white dwarf binary systems. These systems, SDSS J143633.29+501026.8 and SDSS J105353.89+520031.0, were identified by searching for radial velocity variations in the individual exposures that make up the published spectra from the Sloan Digital Sky Survey. We followed up these systems with time series spectroscopy to measure the period and mass ratios of these systems. Although we only place a lower bound on the companion masses, we argue that they must also be white dwarf stars. With periods of approximately 1 hour, we estimate that the systems will merge in less than 100 Myr, but the merger product will likely not be massive enough to result in a Type 1a supernova.

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arXiv2009

Typing Supernova Remnants Using X-ray Line Emission Morphologies

We present a new observational method to type the explosions of young supernova remnants (SNRs). By measuring the morphology of the Chandra X-ray line emission in seventeen Galactic and Large Magellanic Cloud SNRs with a multipole expansion analysis (using power ratios), we find that the core-collapse SNRs are statistically more asymmetric than the Type Ia SNRs. We show that the two classes of supernovae can be separated naturally using this technique because X-ray line morphologies reflect the distinct explosion mechanisms and structure of the circumstellar material. These findings are consistent with recent spectropolarimetry results showing that core-collapse SNe are intrinsically more asymmetric.

astro-ph.HE↗

arXiv2009

First Results from the Swarms Survey. SDSS 1257+5428: A Nearby, Massive White Dwarf Binary with a Likely Neutron Star or Black Hole Companion

We present the first results from SWARMS (Sloan White dwArf Radial velocity data Mining Survey), an ongoing project to identify compact white dwarf (WD) binaries in the spectroscopic catalog of the Sloan Digital Sky Survey. The first object identified by SWARMS, SDSS 1257+5428, is a single-lined spectroscopic binary in a circular orbit with a period of 4.56 hr and a semiamplitude of 322.7+-6.3 km/s. From the spectrum and photometry, we estimate a WD mass of 0.92(+0.28,-0.32) Msun. Together with the orbital parameters of the binary, this implies that the unseen companion must be more massive than 1.62(+0.20,-0.25) Msun, and is in all likelihood either a neutron star or a black hole. At an estimated distance of 48(+10,-19) pc, this would be the closest known stellar remnant of a supernova explosion.

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arXiv2009

The Stellar Ancestry of Supernovae in the Magellanic Clouds - I. the Most Recent Supernovae in the Large Magellanic Cloud

We use the star formation history map of the Large Magellanic Cloud to study the sites of the eight smallest (and presumably youngest) supernova remnants in the Cloud: SN 1987A, N158A, N49, and N63A (core collapse remnants), 0509-67.5, 0519-69.0, N103B, and DEM L71 (Type Ia remnants). The local star formation histories provide unique insights into the nature of the supernova progenitors, which we compare with the properties of the supernova explosions derived from the remnants themselves and from supernova light echoes. We find that all the core collapse supernovae that we have studied are associated with vigorous star formation in the recent past. Stars more massive than 21.5Msun are very scarce around SNR N49, implying that the magnetar SGR 0526-66 in this SNR was either formed elsewhere or came from a progenitor with a mass well below the 30Msun threshold suggested in the literature. Three of our four Ia SNRs are associated with old, metal poor stellar populations. This includes SNR 0509-67.5, which is known to have been originated by an extremely bright Type Ia event, and yet is located very far away from any sites of recent star formation, in a population with a mean age of 7.9 Gyr. The Type Ia SNR N103B, on the other hand, is associated with recent star formation, and might have had a relatively younger and more massive progenitor with substantial mass loss before the explosion. We discuss these results in the context of our present understanding of core collapse and Type Ia supernova progenitors.

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arXiv2009

The End of Amnesia: Measuring the Metallicities of Type Ia SN Progenitors with Manganese Lines in Supernova Remnants

The Mn to Cr mass ratio in supernova ejecta has recently been proposed as a tracer of Type Ia SN progenitor metallicity. We review the advantages and problems of this observable quantity, and discuss them in the framework of the Tycho Supernova Remnant. The fluxes of the Mn and Cr Kalpha lines in the X-ray spectra of Tycho observed by the Suzaku satellite suggests a progenitor of supersolar metallicity.

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arXiv2009

Star Formation Around the Youngest Supernova Remnants in the Large Magellanic Cloud: Implications for Type Ia Supernova Progenitors

We use the star formation history map of the Large Magellanic Cloud recently published by Harris & Zaritsky to study the sites of the youngest Type Ia supernova remnants. We find that most Type Ia remnants are associated with old, metal-poor stellar populations, with little or no recent star formation. These include SNR 0509-67.5 which is known to have been originated by an extremely bright SN 1991T-like event, and yet is located very far away from any star forming regions. The Type Ia remnant SNR N103B, however, is associated with vigorous star formation activity in the last 100 Myr, and might have had a relatively younger and more massive progenitor.

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arXiv2008

Secondary Fe-peak nuclei in the Tycho Supernova Remnant: A Promising Tracer of Type Ia Progenitor Metallicity

The Mn to Cr mass ratio in supernova ejecta has recently been proposed as a tracer of Type Ia SN progenitor metallicity. We review the advantages and problems of this observable quantity, and discuss them in the framework of two Galactic supernova remnants: the well known Tycho SNR and W49B, an older object that has been tentatively classified as Type Ia. The fluxes of the Mn and Cr Ka lines in the X-ray spectra of these SNRs observed by the Suzaku and ASCA satellites suggest progenitors of supersolar metallicity for both objects.

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arXiv2008

The End of Amnesia: A New Method for Measuring the Metallicity of Type Ia Supernova Progenitors Using Manganese Lines in Supernova Remnants

We propose a new method to measure the metallicity of Type Ia supernova progenitors using Mn and Cr lines in the X-ray spectra of young supernova remnants. We show that the Mn to Cr mass ratio in Type Ia supernova ejecta is tightly correlated with the initial metallicity of the progenitor, as determined by the neutron excess of the white dwarf material before thermonuclear runaway. We use this correlation, together with the flux of the Cr and Mn Kalpha X-ray lines in the Tycho supernova remnant recently detected by Suzaku (Tamagawa et al. 2008) to derive a metallicity of log(Z) = -1.32 (+0.67,-0.33) for the progenitor of this supernova, which corresponds to log(Z/Zsun)= 0.60 (+0.31,-0.60) according to the latest determination of the solar metallicity by Asplund et al. (2005). The uncertainty in the measurement is large, but metallicities much smaller than the solar value can be confidently discarded. We discuss the implications of this result for future research on Type Ia supernova progenitors.

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arXiv2008

Morphological evidence for azimuthal variations of the cosmic ray ion acceleration at the blast wave of SN 1006

Using radio, X-ray and optical observations, we present evidence for morphological changes due to efficient cosmic ray ion acceleration in the structure of the southeastern region of the supernova remnant SN 1006. SN 1006 has an apparent bipolar morphology in both the radio and high-energy X-ray synchrotron emission. In the optical, the shock front is clearly traced by a filament of Balmer emission in the southeast. This optical emission enables us to trace the location of the blast wave (BW) even in places where the synchrotron emission from relativistic electrons is either absent or too weak to detect. The contact discontinuity (CD) is traced using images in the low-energy X-rays (oxygen band) which we argue reveals the distribution of shocked ejecta. We interpret the azimuthal variations of the ratio of radii between the BW and CD plus the X-ray and radio synchrotron emission at the BW using CR-modified hydrodynamic models. We assumed different azimuthal profiles for the injection rate of particles into the acceleration process, magnetic field and level of turbulence. We found that the observations are consistent with a model in which these parameters are all azimuthally varying, being largest in the brightest regions.

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arXiv2008

The Persistence of Memory, or How the X-Ray Spectrum of SNR 0509-67.5 Reveals the Brightness of its Parent Type Ia Supernova

We examine the dynamics and X-ray spectrum of the young Type Ia supernova remnant 0509-67.5 in the context of the recent results obtained from the optical spectroscopy of its light echo. Our goal is to estimate the kinetic energy of the supernova explosion using Chandra and XMM-Newton observations of the supernova remnant, thus placing the birth event of 0509-67.5 in the sequence of dim to bright Type Ia supernovae. We base our analysis on a standard grid of one-dimensional delayed detonation explosion models, together with hydrodynamic and X-ray spectral calculations of the supernova remnant evolution. From the remnant dynamics and the properties of the O, Si, S, and Fe emission in its X-ray spectrum we conclude that 0509-67.5 was originated ~400 years ago by a bright, highly energetic Type Ia explosion similar to SN 1991T. Our best model has a kinetic energy of 1.4x10E51 erg and synthesizes 0.97 Msun of 56Ni. These results are in excellent agreement with the age estimate and spectroscopy from the light echo. We have thus established the first connection between a Type Ia supernova and its supernova remnant based on a detailed quantitative analysis of both objects.

astro-ph↗

arXiv2007

Are the Models for Type Ia Supernova Progenitors Consistent with the Properties of Supernova Remnants?

We explore the relationship between the models for progenitor systems of Type Ia supernovae and the properties of the supernova remnants that evolve after the explosion. Most models for Type Ia progenitors in the single degenerate scenario predict substantial outflows during the presupernova evolution. Expanding on previous work, we estimate the imprint of these outflows on the structure of the circumstellar medium at the time of the supernova explosion, and the effect that this modified circumstellar medium has on the evolution of the ensuing supernova remnant. We compare our simulations with the observational properties of known Type Ia supernova remnants in the Galaxy (Kepler, Tycho, SN 1006), the Large Magellanic Cloud (0509-67.5, 0519-69.0, N103B), and M31 (SN 1885). We find that optically thick outflows from the white dwarf surface (sometimes known as accretion winds) with velocities above 200 km/s excavate large low-density cavities around the progenitors. Such large cavities are incompatible with the dynamics of the forward shock and the X-ray emission from the shocked ejecta in all the Type Ia remnants that we have examined.

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arXiv2006

Can Ejecta-Dominated Supernova Remnants be Typed from their X-ray Spectra? The Case of G337.2-0.7

In this paper we use recent X-ray and radio observations of the ejecta-rich Galactic supernova remnant (SNR) G337.2-0.7 to determine properties of the supernova (SN) explosion that formed this source. H I absorption measurements from the Australia Telescope Compact Array (ATCA) constrain the distance to G337.2-0.7 to lie between 2.0 +/- 0.5 and 9.3 +/- 0.3 kpc. Combined with a clear radio image of the outer blast-wave, this distance allows us to estimate the dynamical age (between 750 and 3500 years) from the global X-ray spectrum obtained with the XMM-Newton and Chandra observatories. The presence of ejecta is confirmed by the pattern of fitted relative abundances, which show Mg, Ar and Fe to be less enriched (compared to solar) than Si, S or Ca, and the ratio of Ca to Si to be 3.4 +/- 0.8 times the solar value (under the assumption of a single electron temperature and single ionization timescale). With the addition of a solar abundance component for emission from the blast-wave, these abundances (with the exception of Fe) resemble the ejecta of a Type Ia, rather than core-collapse, SN. Comparing directly to models of the ejecta and blast-wave X-ray emission calculated by evolving realistic SN Ia explosions to the remnant stage allows us to deduce that one-dimensional delayed detonation and pulsed delayed detonation models can indeed reproduce the major features of the global spectrum. In particular, stratification of the ejecta, with the Fe shocked most recently, is required to explain the lack of prominent Fe-K emission.

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arXiv2006

Constraints on the Physics of Type Ia Supernovae from the X-Ray Spectrum of the Tycho Supernova Remnant

In this paper we use high quality X-ray observations from XMM-Newton and Chandra to gain new insights into the explosion that originated Tycho's supernova 433 years ago. We perform a detailed comparison between the ejecta emission from the spatially integrated X-ray spectrum of the supernova remnant and current models for Type Ia supernova explosions. We use a grid of synthetic X-ray spectra based on hydrodynamic models of the evolution of the supernova remnant and self-consistent nonequilibrium ionization calculations for the state of the shocked plasma. We find that the fundamental properties of the X-ray emission in Tycho are well reproduced by a one-dimensional delayed detonation model with a kinetic energy of 1.2e51 erg. All the other paradigms for Type Ia explosions that we have tested fail to provide a good approximation to the observed ejecta emission, including one-dimensional deflagrations, pulsating delayed detonations and sub-Chandrasekhar explosions, as well as deflagration models calculated in three dimensions. Our results require that the supernova ejecta retain some degree of chemical stratification, with Fe-peak elements interior to intermediate mass elements. This strongly suggests that a supersonic burning front (i.e., a detonation) must be involved at some stage in the physics of Type Ia supernova explosions.

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arXiv2004

A Million-Second Chandra View of Cassiopeia A

We introduce a million-second observation of the supernova remnant Cassiopeia A with the Chandra X-ray Observatory. The bipolar structure of the Si-rich ejecta (NE jet and SW counterpart) is clearly evident in the new images, and their chemical similarity is confirmed by their spectra. These are most likely due to jets of ejecta as opposed to cavities in the circumstellar medium, since we can reject simple models for the latter. The properties of these jets and the Fe-rich ejecta will provide clues to the explosion of Cas A.

astro-ph↗

arXiv2003

Thermonuclear supernova explosions and their remnants: the case of Tycho

We propose to use the thermal X-ray emission from young supernova remnants (SNRs) originated in Type Ia supernovae (SNe) to extract relevant information concerning the explosion mechanism. We focus on the differences between numerical 1D and 3D explosion calculations, and the impact that these differences could have on young SNRs. We use the remnant of the Tycho supernova (SN 1572) as a test case to compare with our predictions, discussing the observational features that allow to accept or discard a given model.

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arXiv2003

Thermal X-ray emission from shocked ejecta in Type Ia Supernova Remnants. Prospects for explosion mechanism identification

The explosion mechanism behind Type Ia supernovae is a matter of continuing debate. The diverse attempts to identify or at least constrain the physical processes involved in the explosion have been only partially successful so far. In this paper we propose to use the thermal X-ray emission from young supernova remnants originated in Type Ia events to extract relevant information concerning the explosions themselves. We have produced a grid of thermonuclear supernova models representative of the paradigms currently under debate: pure deflagrations, delayed detonations, pulsating delayed detonations and sub-Chandrasekhar explosions, using their density and chemical composition profiles to simulate the interaction with the surrounding ambient medium and the ensuing plasma heating, non-equilibrium ionization and thermal X-ray emission of the ejecta. Key observational parameters such as electron temperatures, emission measures and ionization time scales are presented and discussed. We find that not only is it possible to identify the explosion mechanism from the spectra of young Type Ia Supernova Remnants, it is in fact necessary to take the detailed ejecta structure into account if such spectra are to be modeled in a self-consistent way. Neither element line flux ratios nor element emission measures are good estimates of the true ratios of ejected masses, with differences of as much as two or three orders of magnitude for a given model. Comparison with observations of the Tycho SNR suggests a delayed detonation as the most probable explosion mechanism. Line strengths, line ratios, and the centroid of the Fe Kalpha line are reasonably well reproduced by a model of this kind.

astro-ph↗

arXiv2002

Prospects for SNIa Explosion Mechanism Identification Through Supernova Remnants

We present the first results from an ongoing work aimed to use supernovae remnants to discriminate among different type Ia supernovae explosion models. We have computed the hydrodynamic interaction of supernova ejecta with the interstellar medium, obtaining the evolution of the density, temperature and ionization structure of the remnant. We have used ejecta profiles obtained from 1D hydrodynamic calculations of the different explosion mechanisms that are currently under debate. We have analyzed the best indicators that allow to discriminate among the different explosion mechanisms, taking into account the diversity of scenarios proposed for the presupernova evolution of the binary system, and the uncertain amount of electron heating in collisionless shocks.

astro-ph↗

arXiv2001

The Imprint of Presupernova Evolution on Supernovae Remnants

The evolution of type Ia supernova binary system progenitors is highly uncertain. Several evolutionary models predict that the accretion of mass onto the white dwarf is accompanied by mass ejection from the binary in the form of a powerful wind, but very few observations have been made during the initial phase of formation of supernovae remnants, when the interaction of supernova ejecta with presupernova wind could be tested. Here we present hydrodynamical simulations of supernova ejecta interaction with an ambient medium modified by presupernova wind. The structure of the ambient medium when the supernova explodes is very sensitive to the details of wind history, and the evolution of the supernova remnant can be affected during several thousand years. We have found that the forward shock expansion parameter is a good tool for discriminating between several wind models. The evolution of the supernova remnant in the presence of an ambient medium modified by interaction with pre-supernova wind cannot be described by a similarity solution. We also rule out simple models based on a circumstellar medium that merges smoothly with a uniform density ambient medium.

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