A<i>CHANDRA</i>X-RAY SURVEY OF EJECTA IN THE CASSIOPEIA A SUPERNOVA REMNANT

Hwang, U.; Laming, J. M.

doi:10.1088/0004-637x/746/2/130

Cited by 169 publications

(271 citation statements)

References 104 publications

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“…It was observed in the upper TeV by Milagro with a significance of 3σ (Abdo et al 2009b). Figure 16 shows the predicted muon neutrino spectra after considering oscillations for these two SNRs and Cas A (Hwang & Laming 2012;Araya & Cui 2010;Abdo et al 2010a). The 90% C.L.…”

Section: Implications For Models Of Astrophysical Neutrinosmentioning

confidence: 90%

SEARCH FOR TIME-INDEPENDENT NEUTRINO EMISSION FROM ASTROPHYSICAL SOURCES WITH 3 yr OF IceCube DATA

Aartsen

Abbasi

Abdou

et al. 2013

ApJ

104

129

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We present the results of a search for neutrino point sources using the IceCube data collected between 2008 April and 2011 May with three partially completed configurations of the detector: the 40-, 59-, and 79-string configurations. The live-time of this data set is 1040 days. An unbinned maximum likelihood ratio test was used to search for an excess of neutrinos above the atmospheric background at any given direction in the sky. By adding two more years of data with improved event selection and reconstruction techniques, the sensitivity was improved by a factor of 3.5 or more with respect to the previously published results obtained with the 40-string configuration of IceCube. We performed an all-sky survey and a dedicated search using a catalog of a priori selected objects observed by other telescopes. In both searches, the data are compatible with the background-only hypothesis. In the absence of evidence for a signal, we set upper limits on the flux of muon neutrinos. For an E −2 neutrino spectrum, the observed limits are (0.9-5) × 10 −12 TeV −1 cm −2 s −1 for energies between 1 TeV and 1 PeV in the northern sky and (0.9-23.2) × 10 −12 TeV −1 cm −2 s −1 for energies between 10 2 TeV and 10 2 PeV in the southern sky. We also report upper limits for neutrino emission from groups of sources that were selected according to theoretical models or observational parameters and analyzed with a stacking approach. Some of the limits presented already reach the level necessary to quantitatively test current models of neutrino emission.

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Section: Implications For Models Of Astrophysical Neutrinosmentioning

confidence: 90%

SEARCH FOR TIME-INDEPENDENT NEUTRINO EMISSION FROM ASTROPHYSICAL SOURCES WITH 3 yr OF IceCube DATA

Aartsen

Abbasi

Abdou

et al. 2013

ApJ

104

129

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“…To the southeast, iron-rich ejecta extend beyond the Bright Ring and into the plateau. The jets and extended iron-rich structure are likely the result of an asymmetric explosion of the progenitor (see, e.g., Hughes et al 2000;Hwang & Laming 2012). The light echo data also indicate an asymmetric explosion (Rest et al 2011).…”

Section: General Background On Cas Amentioning

confidence: 97%

“…We can also compare the density of the unshocked ejecta to the hydrodynamic model of Hwang & Laming (2012). Their ejecta model assumes a uniform density core surrounded by a power-law envelope.…”

Section: Comparison With Theoretical Expectations For Density and Massmentioning

confidence: 99%

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The Density and Mass of Unshocked Ejecta in Cassiopeia a Through Low Frequency Radio Absorption

DeLaney

Kassim

Rudnick

et al. 2014

ApJ

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Characterizing the ejecta in young supernova remnants is a requisite step toward a better understanding of stellar evolution. In Cassiopeia A the density and total mass remaining in the unshocked ejecta are important parameters for modeling its explosion and subsequent evolution. Low frequency (<100 MHz) radio observations of sufficient angular resolution offer a unique probe of unshocked ejecta revealed via free-free absorption against the synchrotron emitting shell. We have used the Very Large Array plus Pie Town Link extension to probe this cool, ionized absorber at 9 and 18. 5 resolution at 74 MHz. Together with higher frequency data we estimate an electron density of 4.2 cm −3 and a total mass of 0.39 M with uncertainties of a factor of ∼2. This is a significant improvement over the 100 cm −3 upper limit offered by infrared [S iii] line ratios from the Spitzer Space Telescope. Our estimates are sensitive to a number of factors including temperature and geometry. However using reasonable values for each, our unshocked mass estimate agrees with predictions from dynamical models. We also consider the presence, or absence, of cold iron-and carbon-rich ejecta and how these affect our calculations. Finally we reconcile the intrinsic absorption from unshocked ejecta with the turnover in Cas A's integrated spectrum documented decades ago at much lower frequencies. These and other recent observations below 100 MHz confirm that spatially resolved thermal absorption, when extended to lower frequencies and higher resolution, will offer a powerful new tool for low frequency astrophysics.

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“…In particular, it might allow one to discriminate our gravitational tug-boat mechanism from scenarios like the neutrino-driven kicks discussed by Fryer & Kusenko (2006), who expect the stronger explosion (and thus enhanced explosive nucleosynthesis) in the direction of the NS motion. High-resolution spectral investigations of young SN remnants like Puppis A (Katsuda et al 2008(Katsuda et al , 2010, G11.2-0.3 (Moon et al 2009), and Cassiopeia A (Isensee et al 2010;DeLaney et al 2010;Rest et al 2011;Hwang & Laming 2012) in different wavebands may offer a promising perspective.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional neutrino-driven supernovae: Neutron star kicks, spins, and asymmetric ejection of nucleosynthesis products

Wongwathanarat

Janka

Müller

2013

A&A

267

376

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We present three-dimensional (3D) simulations of supernova explosions of nonrotating stars, triggered by the delayed neutrinoheating mechanism with a suitable choice of the core-neutrino luminosity. Our results show that asymmetric mass ejection caused by hydrodynamic instabilities can accelerate the neutron star (NS) up to recoil velocities of more than 700 km s −1 by the "gravitational tug-boat mechanism", which is sufficient to explain most observed pulsar space velocities. The associated NS spin periods for our nonrotating progenitors are about 100 ms to 8000 ms without any obvious correlation between spin and kick magnitudes or directions. This suggests that faster spins and a possible spin-kick alignment might require angular momentum in the progenitor core prior to collapse. Our simulations for the first time demonstrate a clear correlation between the size of the NS kick and anisotropic production and distribution of heavy elements created by explosive burning behind the shock. In the case of large pulsar kicks, the explosion is significantly stronger opposite to the kick vector. Therefore the bulk of the explosively fused iron-group elements, in particular nickel, are ejected mostly in large clumps against the kick direction. This contrasts with the case of low recoil velocity, where the nickelrich lumps are more isotropically distributed. Explosively produced intermediate-mass nuclei heavier than 28 Si (like 40 Ca and 44 Ti) also exhibit significant enhancement in the hemisphere opposite to the direction of fast NS motion, while the distribution of 12 C, 16 O, and 20 Ne is not affected, and that of 24 Mg only marginally. Mapping the spatial distribution of the heavy elements in supernova remnants with identified pulsar motion may offer an important diagnostic test of the kick mechanism. Unlike kick scenarios based on anisotropic neutrino emission, our hydrodynamical acceleration model predicts enhanced ejection of iron-group elements and of their nuclear precursors in the opposite direction to the NS recoil.

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ACHANDRAX-RAY SURVEY OF EJECTA IN THE CASSIOPEIA A SUPERNOVA REMNANT

Cited by 169 publications

References 104 publications

SEARCH FOR TIME-INDEPENDENT NEUTRINO EMISSION FROM ASTROPHYSICAL SOURCES WITH 3 yr OF IceCube DATA

SEARCH FOR TIME-INDEPENDENT NEUTRINO EMISSION FROM ASTROPHYSICAL SOURCES WITH 3 yr OF IceCube DATA

The Density and Mass of Unshocked Ejecta in Cassiopeia a Through Low Frequency Radio Absorption

Three-dimensional neutrino-driven supernovae: Neutron star kicks, spins, and asymmetric ejection of nucleosynthesis products

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