Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
6,819
result(s) for
"Supernova remnants"
Sort by:
Astroquizzical : solving the cosmic puzzles of our planets, stars and galaxies
\"Looking up at the night sky, we see not only stars twinkling in their constellations and planets caught mid-orbit but our cosmic family tree. We are here on Earth because billions of years ago the Big Bang created the atoms that, over unimaginable periods of time, formed the stars and galaxies. Generations of stars that burned, exploded, or collided long before our planet was formed created the carbon of our bodies and the iron in our blood. In Astroquizzical, astrophysicist Jillian Scudder takes readers on a curiosity-driven journey through outer space, traveling back in time from Earth to the stars and galaxies to the cosmic explosions of the Big Bang. Scudder proceeds--astroquizzically--question by question, answering and explaining such queries as \"What color is the universe?,\" \"Do all planets spin the same way?,\" and \"How many galaxies are there?\" Along the way, she proposes a series of thought experiments, including \"What would happen if we split the sun in half?\" and \"What happens to time dilation at the speed of light?\" She covers meteors, the aurora, and the Moon (Earth's cosmic companion); Jupiter's stripes and Pluto's mountains; red dwarfs, brown dwarfs, and white dwarfs; the deaths of stars and the abundance of galaxies; and much more. Striking color images illustrate astrophysical marvels.\" -- Back Cover
Book
Linking the X3D Pathway to Integral Field Spectrographs: YSNR 1E 0102.2-7219 in the SMC as a Case Study
The concept of the x3d pathway was introduced by Vogt et al. as a new approach to sharing and publishing three-dimensional structures interactively in online scientific journals. The core characteristics of the x3d pathway are that: (1) it does not rely on specific software, but rather a file format (x3d), (2) it can be implemented using fully open-source tools, and (3) article readers can access the interactive models using most main stream web browsers without the need for any additional plugins. In this article, we further demonstrate the potential of the x3d pathway to visualize data sets from optical integral field spectrographs. We use recent observations of the oxygen-rich young supernova remnant 1E 0102.2-7219 in the Small Magellanic Cloud to implement additional x3dom tools & techniques and expand the range of interactions that can be offered to article readers. In particular, we present a set of javascript functions allowing the creation and interactive handling of clip planes, effectively allowing users to take measurements of distances and angles directly from the interactive model itself.
Journal Article
The Kinematic Distances of SNR G16.7+0.1 and G15.9+0.2 by Analyzing H i Absorption Spectra
We build H i absorption spectra toward Supernova Remnant (SNRs) G16.7+0.1 and G15.9+0.2 using the THOR survey data. With the absorption spectra, we give a new distance range of 7-16 kpc for G15.9+0.2. We also resolve the near/far-side distance ambiguity of G16.7+0.1 and confirm its kinematic distance of about 14 kpc. In addition, we analyze the CO (J = 3-2) spectra toward G16.7+0.1 and find obvious CO emission at the 20 km s−1 OH 1720 MHz maser site. This supports Reynoso & Mangum suggestions that the velocity difference between the maser and southern molecular cloud is caused by the shock acceleration. We discuss the impact of the distances on other physical parameters of the two SNRs.
Journal Article
MHD lensing in inhomogeneous ISM for qualitative understanding of the morphology of supernova remnants
Morphological evolution of expanding shells of fast-mode magnetohydrodynamic (MHD) waves through an inhomogeneous ISM is investigated in order to qualitatively understand the complicated morphology of shell-type supernova remnants (SNR). Interstellar clouds with high Alfvén velocity act as concave lenses to diverge the MHD waves, while those with slow Alfvén velocity act as convex lenses to converge the waves to the focal points. By combination of various types of clouds and fluctuations with different Alfvén velocities, sizes, or wavelengths, the MHD-wave shells attain various morphological structures, exhibiting filaments, arcs, loops, holes, and focal strings, mimicking old and deformed SNRs.
Journal Article
The interstellar medium in young supernova remnants: key to the production of cosmic X-rays and γ-rays
We review recent progress in elucidating the relationship between high-energy radiation and the interstellar medium (ISM) in young supernova remnants (SNRs) with ages of ∼2000 yr, focusing in particular on RX J1713.7−3946 and RCW 86. Both SNRs emit strong nonthermal X-rays and TeV γ-rays, and they contain clumpy distributions of interstellar gas that includes both atomic and molecular hydrogen. We find that shock–cloud interactions provide a viable explanation for the spatial correlation between the X-rays and ISM. In these interactions, the supernova shocks hit the typically pc-scale dense cores, generating a highly turbulent velocity field that amplifies the magnetic field up to 0.1–1 mG. This amplification leads to enhanced nonthermal synchrotron emission around the clumps, whereas the cosmic-ray electrons do not penetrate the clumps. Accordingly, the nonthermal X-rays exhibit a spatial distribution similar to that of the ISM on the pc scale, while they are anticorrelated at sub-pc scales. These results predict that hadronic γ-rays can be emitted from the dense cores, resulting in a spatial correspondence between the γ-rays and the ISM. The current pc-scale resolution of γ-ray observations is too low to resolve this correspondence. Future γ-ray observations with the Cherenkov Telescope Array will be able to resolve the sub-pc-scale γ-ray distribution and provide clues to the origin of these cosmic γ-rays.
Journal Article
Identifying a Point-Symmetrical Morphology in the Core-Collapse Supernova Remnant W44
I identify a point-symmetrical morphology in the core-collapse supernova remnant (CCSNR) W44 compatible with shaping by three or more pairs of jets in the jittering jets explosion mechanism (JJEM). Motivated by recent identifications of point-symmetrical morphologies in CCSNRs and their match to the JJEM, I revisit the morphological classification of CCSNR W44. I examine a radio map of W44 and find the outer bright rim of the radio map to possess a point-symmetric structure compatible with shaping by two energetic pairs of opposite jets rather than an S-shaped morphology shaped by a precessing pair of jets. An inner pair of filaments might hint at a third powerful pair of jets. More pairs of jets were involved in the explosion process. This study adds to the growing evidence that the JJEM is the primary explosion mechanism of core-collapse supernovae.
Journal Article
Gamma-Ray emission from the shell of supernova remnant W44 revealed by the Fermi LAT
Recent observations of supernova remnants (SNRs) hint that they accelerate cosmic rays to energies close to ~1015 electron volts. However, the nature of the particles that produce the emission remains ambiguous. We report observations of SNR W44 with the Fermi Large Area Telescope at energies between 2 × 108 electron volts and 3 ×1011 electron volts. The detection of a source with a morphology corresponding to the SNR shell implies that the emission is produced by particles accelerated there. The gamma-ray spectrum is well modeled with emission from protons and nuclei. Its steepening above ~109 electron volts provides a probe with which to study how particle acceleration responds to environmental effects such as shock propagation in dense clouds and how accelerated particles are released into interstellar space
Publication
Far-Infrared Emission from a Late Supernova Remnant in an Inhomogeneous Medium
Interstellar dust particles are swept up during the expansion of a supernova (SN) remnant, penetrate behind the shock wave front, where they are heated and destroyed in the hot gas. This leads to a change in the emission properties of such particles. The paper considers the evolution of the infrared (IR) luminosity of an SN remnant expanding in an inhomogeneous interstellar medium with a lognormal distribution of density perturbations. The IR luminosity of the swept up interstellar dust increases rapidly during the first few thousand years after the SN explosion and reaches a maximum. It then decreases due to the destruction of particles in the hot gas and a drop in their emissivity in the cooling gas of the shell. The dependence of the evolution of the IR luminosity of the dust in the remnant on the gas density dispersion ahead of the shock wave front from the SN is shown. It was found that the band centered at 70 m can be considered as the most optimal for studying late remnants, since the maximum IR luminosity is located within its limits for a significant time (40–50 kyr). During the evolution, the dust temperature changes from 70 to 20 K and weakly depends on the level of inhomogeneity of the medium. During the radiative phase, strong lines of metal ions appear in the remnant spectra against the dust continuum. Their luminosity grows rapidly and exceeds the luminosity of dust in the continuum under the line by approximately 10–10 times. The moment of achieving high luminosity in the lines depends significantly on the inhomogeneity of the medium. The possibilities of observing IR emission both in the dust continuum and in the lines are discussed. It is expected that their ratios will allow us to estimate the magnitude of inhomogeneity of the medium in which the remnant is expanding.
Journal Article
Radio emission from interstellar shocks: Young type Ia supernova remnants and the case of N 103B in the Large Magellanic Cloud
We investigate young type Ia supernova remnants (SNRs) in our Galaxy and neighbouring galaxies in order to understand their properties and early stage of their evolution. Here we present a radio continuum study based on new and archival data from the Australia Telescope Compact Array (ATCA) towards N 103B, a young (≤1000 yrs) spectroscopically confirmed type Ia SNR in the Large Magellanic Cloud (LMC) and proposed to have originated from a single degenerate (SD) progenitor. The radio morphology of this SNR is asymmetrical with two bright regions towards the north-west and south-west of the central location as defined by radio emission.N 103B identified features include: a radio spectral index of −0.75±0.01\\(-0.75\\pm 0.01\\) (consistent with other young type Ia SNRs in the Galaxy); a bulk SNR expansion rate as in X-rays; morphology and polarised electrical field vector measurements where we note radial polarisation peak towards the north-west of the remnant at both 5500 and 9000 MHz. The spectrum is concave-up and the most likely reason is the non-linear diffusive shock acceleration (NLDSA) effects or presence of two different populations of ultra-relativistic electrons.We also note unpolarised clumps near the south-west region which is in agreement with this above scenario. We derive a typical magnetic field strength for N 103B of 16.4 μG for an average rotation measurement of 200radm−2\\(200~\\mbox{rad}\\,\\mbox{m}^{-2}\\). However, we estimate the equipartition field to be of the order of ∼235 μG with an estimated minimum energy of Emin=6.3×1048erg\\(E_{\\mathrm{min}}=6.3\\times 10^{48}~\\mbox{erg}\\). The close (∼0.5∘\\(\\sim 0.5^{\\circ }\\)) proximity of N 103B to the LMC mid-plane indicates that an early encounter with dense interstellar medium may have set an important constrain on SNR evolution.Finally, we compare features of N 103B to six other young type Ia SNRs in the LMC and Galaxy, with a range of proposed degeneracy scenarios to highlight potential differences due to a different models. We suggest that the single degenerate scenario might point to morphologically asymmetric type Ia supernova explosions.
Journal Article
Low X-ray Efficiency of a Young High-B Pulsar PSR J1208−6238 Observed with Chandra
High magnetic field (high-B) pulsars are key sources to bridge magnetars and conventional rotation powered pulsars, and thus to understand the origin of magnetar activities. We have estimated a tight upper limit on the X-ray flux of one of the youngest high-B pulsars PSR J1208−6238 for the first time; a Chandra 10 ks observation shows no significant source. Depending on the emission models, we have the 3σ upper limit on the intrinsic 0.5–7 keV flux to 2.2–10.0×10−14 erg s−1 cm−2. Assuming the distance to the pulsar to be 3 kpc, we suggest that the conversion efficiency from the spin-down energy to the X-ray luminosity of this pulsar is almost the smallest among known high-B pulsars, and even smaller for those for a typical rotation-powered one. We also discuss possible associations of a surrounding pulsar wind nebula and a hosting supernova remnant around this high-B pulsar.
Journal Article