scholarly journals Statistical tests of young radio pulsars with/without supernova remnants: implying two origins of neutron stars

2021 ◽  
Vol 508 (1) ◽  
pp. 279-286
Author(s):  
Xiang-Han Cui ◽  
Cheng-Min Zhang ◽  
Di Li ◽  
Jian-Wei Zhang ◽  
Bo Peng ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
Statistical Tests ◽  
High Energy ◽  
Iron Core ◽  
Cumulative Number ◽  
Radio Pulsars ◽  
Surface Magnetic Field ◽  
Spin Period ◽  
Two Samples ◽  
Energy Emissions

ABSTRACT The properties of the young pulsars and their relations to the supernova remnants (SNRs) have been the interesting topics. At present, 383 SNRs in the Milky Way Galaxy have been published, which are associated with 64 radio pulsars and 46 pulsars with high-energy emissions. However, we noticed that 630 young radio pulsars with the spin periods of less than half a second have been not yet observed the SNRs surrounding or nearby them, which arises a question of that could the two types of young radio pulsars with/without SNRs hold the distinctive characteristics? Here, we employ the statistical tests on the two groups of young radio pulsars with (52) and without (630) SNRs to reveal if they share the different origins. Kolmogorov–Smirnov (K–S) and Mann–Whitney–Wilcoxon (M–W–W) tests indicate that the two samples have the different distributions with parameters of spin period (P), derivative of spin period ($\dot{P}$), surface magnetic field strength (B), and energy loss rate ($\dot{E}$). Meanwhile, the cumulative number ratio between the pulsars with and without SNRs at the different spin-down ages decreases significantly after $\rm 10\!-\!20\, kyr$. So we propose that the existence of the two types of supernovae (SNe), corresponding to their SNR lifetimes, which can be roughly ascribed to the low- and high-energy SNe. Furthermore, the low-energy SNe may be formed from the $\rm 8\!-\!12\, M_{\odot }$ progenitor, e.g. possibly experiencing the electron capture, while the main-sequence stars of $\rm 12\!-\!25\, M_{\odot }$ may produce the high-energy SNe probably by the iron core collapse.

scholarly journals X-rays from Radio Pulsars: The Portable Supernova Remnants

1983 ◽  
Vol 101 ◽  
pp. 471-484 ◽  
Author(s):  
David J. Helfand
Keyword(s):  
Neutron Stars ◽  
Supernova Remnants ◽  
High Energy ◽  
Particle Accelerator ◽  
High Energy Particle ◽  
X Rays ◽  
Radio Pulsars ◽  
High Energy Radiation ◽  
Origin And Evolution ◽  
Supernova Explosions

Neutron stars are the longest-lived remnants of supernova explosions. As a reservoir of thermal energy remaining from the explosion and generated by frictional coupling between core and crust, as a storehouse of magnetic and rotational kinetic energy which allows the star to act as a high energy particle accelerator, and as the source of a deep gravitational potential which can generate heat from infalling matter, neutron stars remain capable of producing high energy radiation for a Hubble time. We review here the results of an extensive survey of supernova remnants and radio pulsars with the imaging instruments on board the Einstein Observatory and discuss the implications of these results for pulsar physics and for the origin and evolution of galactic neutron stars.

Temporal evolution of isolated pulsars; Age-Tau problem

2014 ◽  
Vol 23 (10) ◽  
pp. 1450083 ◽  
Author(s):  
Pinar Kutukcu ◽  
Askin Ankay
Keyword(s):  
Magnetic Field ◽  
Supernova Remnants ◽  
Period Change ◽  
Spin Axis ◽  
Radio Pulsars ◽  
Spin Period ◽  
Decay Times ◽  
Dipole Magnetic Field ◽  
Order Of Magnitude ◽  
Surface Dipole

In this work, we examine the evolution of a sample of isolated pulsars connected to Galactic supernova remnants (SNRs) five of which have measured braking indices. For the pulsars in our sample without measured braking index values we have calculated the estimated braking indices adopting the supernova remnant ages as the real ages of pulsar-SNR pairs assuming short initial spin periods (10–30 ms). Some of these pulsars exhibit at least one order of magnitude differences between the characteristic pulsar ages and the ages of the SNRs they are physically connected to. We adopt an exponential B-decay model, which is the decrease in the surface dipole magnetic field component perpendicular to the spin axis, in order to explain the evolutions of such pulsars on the spin period versus the spin period change diagram. The decay can be either due to a decrease in the angle between the spin axis and the magnetic axis and/or due to a decay in the surface dipole magnetic field itself. Based on a previous work by Ankay et al. on the X-ray pulsar 1E1207-5209 we show that there are some other young isolated pulsars which experience B-decay as the predominant effect throughout their observational lifetimes. As compared to ordinary radio pulsars the magneto-dipole radiation torques are not so effective for such pulsars and the characteristic decay times are significantly shorter (about three orders of magnitude). Assuming simple exponential evolutionary tracks we give possible physical interpretations for this new class of neutron stars by examining the observational data of each pulsar-SNR pair.

scholarly journals Modelling spreading of an infection using time series by a novel family of models; fitting the time series of the confirmed cases of COVID-19 in China

2020 ◽  
Vol 9 (s1) ◽  
Author(s):  
Babak Jamshidi ◽  
Shahriar Jamshidi Zargaran ◽  
Mansour Rezaei
Keyword(s):  
Infectious Disease ◽  
Time Series ◽  
Communicable Disease ◽  
Time Series Models ◽  
Cumulative Number ◽  
The Novel ◽  
New Family ◽  
Two Samples ◽  
Almost All ◽  
Number Of Individuals

AbstractIntroductionTime series models are one of the frequently used methods to describe the pattern of spreading an epidemic.MethodsWe presented a new family of time series models able to represent the cumulative number of individuals that contracted an infectious disease from the start to the end of the first wave of spreading. This family is flexible enough to model the propagation of almost all infectious diseases. After a general discussion on competent time series to model the outbreak of a communicable disease, we introduced the new family through one of its examples.ResultsWe estimated the parameters of two samples of the novel family to model the spreading of COVID-19 in China.DiscussionOur model does not work well when the decreasing trend of the rate of growth is absent because it is the main presumption of the model. In addition, since the information on the initial days is of the utmost importance for this model, one of the challenges about this model is modifying it to get qualified to model datasets that lack the information on the first days.

scholarly journals 1.5 °C degrowth scenarios suggest the need for new mitigation pathways

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lorenz T. Keyßer ◽  
Manfred Lenzen
Keyword(s):  
Technological Change ◽  
High Speed ◽  
Large Scale ◽  
High Energy ◽  
Climate Mitigation ◽  
Intergovernmental Panel ◽  
Economic Output ◽  
Integrated Assessment Modelling ◽  
Negative Emissions ◽  
Energy Emissions

Abstract1.5  °C scenarios reported by the Intergovernmental Panel on Climate Change (IPCC) rely on combinations of controversial negative emissions and unprecedented technological change, while assuming continued growth in gross domestic product (GDP). Thus far, the integrated assessment modelling community and the IPCC have neglected to consider degrowth scenarios, where economic output declines due to stringent climate mitigation. Hence, their potential to avoid reliance on negative emissions and speculative rates of technological change remains unexplored. As a first step to address this gap, this paper compares 1.5  °C degrowth scenarios with IPCC archetype scenarios, using a simplified quantitative representation of the fuel-energy-emissions nexus. Here we find that the degrowth scenarios minimize many key risks for feasibility and sustainability compared to technology-driven pathways, such as the reliance on high energy-GDP decoupling, large-scale carbon dioxide removal and large-scale and high-speed renewable energy transformation. However, substantial challenges remain regarding political feasibility. Nevertheless, degrowth pathways should be thoroughly considered.

scholarly journals A New View on Young Pulsars in Supernova Remnants: Slow, Radio-quiet & X-ray Bright

2000 ◽  
Vol 177 ◽  
pp. 699-702 ◽  
Author(s):  
E. V. Gotthelf ◽  
G. Vasisht
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Supernova Remnants ◽  
Simple Explanation ◽  
Crab Pulsar ◽  
Radio Pulsars ◽  
Substantial Fraction ◽  
Subsequent Evolution ◽  
X Ray ◽  
Field Decay

AbstractWe propose a simple explanation for the apparent dearth of radio pulsars associated with young supernova remnants (SNRs). Recent X-ray observations of young remnants have revealed slowly rotating (P∼ 10s) central pulsars with pulsed emission above 2 keV, lacking in detectable radio emission. Some of these objects apparently have enormous magnetic fields, evolving in a manner distinct from the Crab pulsar. We argue that these X-ray pulsars can account for a substantial fraction of the long sought after neutron stars in SNRs and that Crab-like pulsars are perhaps the rarer, but more highly visible example of these stellar embers. Magnetic field decay likely accounts for their high X-ray luminosity, which cannot be explained as rotational energy loss, as for the Crab-like pulsars. We suggest that the natal magnetic field strength of these objects control their subsequent evolution. There are currently almost a dozen slow X-ray pulsars associated with young SNRs. Remarkably, these objects, taken together, represent at least half of the confirmed pulsars in supernova remnants. This being the case, these pulsars must be the progenitors of a vast population of previously unrecognized neutron stars.

scholarly journals The interstellar medium in young supernova remnants: key to the production of cosmic X-rays and $\gamma $-rays

2021 ◽  
Vol 366 (6) ◽  
Author(s):  
Hidetoshi Sano ◽  
Yasuo Fukui
Keyword(s):  
Interstellar Medium ◽  
Supernova Remnants ◽  
Cosmic Ray ◽  
High Energy ◽  
X Rays ◽  
Interstellar Gas ◽  
High Energy Radiation ◽  
Dense Cores ◽  
The Relationship ◽  
Turbulent Velocity Field

AbstractWe 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 $\gamma $ 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 $\gamma $ γ -rays can be emitted from the dense cores, resulting in a spatial correspondence between the $\gamma $ γ -rays and the ISM. The current pc-scale resolution of $\gamma $ γ -ray observations is too low to resolve this correspondence. Future $\gamma $ γ -ray observations with the Cherenkov Telescope Array will be able to resolve the sub-pc-scale $\gamma $ γ -ray distribution and provide clues to the origin of these cosmic $\gamma $ γ -rays.

scholarly journals HIGH-ENERGY EMISSIONS FROM THE GAMMA-RAY BINARY LS 5039

2014 ◽  
Vol 790 (1) ◽  
pp. 18 ◽  
Author(s):  
J. Takata ◽  
Gene C. K. Leung ◽  
P. H. T. Tam ◽  
A. K. H. Kong ◽  
C. Y. Hui ◽  
...  
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Energy Emissions

scholarly journals High-Energy Emissions Induced by Air Density Fluctuations of Discharges

2018 ◽  
Vol 45 (10) ◽  
pp. 5194-5203 ◽  
Author(s):  
C. Köhn ◽  
O. Chanrion ◽  
T. Neubert
Keyword(s):  
High Energy ◽  
Density Fluctuations ◽  
Air Density ◽  
Energy Emissions

scholarly journals Low frequency radio counterparts of HESS J1731−347 a.k.a SNR G353.6−0.7

2017 ◽  
Vol 12 (S331) ◽  
pp. 201-205
Author(s):  
A. J. Nayana ◽  
Poonam Chandra
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Supernova Remnants ◽  
Low Frequency ◽  
High Energy ◽  
Spectral Indices ◽  
Thermal Radio Emission ◽  
Very High Energy ◽  
Γ Rays ◽  
Very High

AbstractHESS J1731−347 a.k.a. SNR G353.6−0.7 is one of the five known very high energy (VHE, Energy > 0.1 TeV) shell-type supernova remnants. We carried out Giant Metrewave Radio Telescope (GMRT) observations of this TeV SNR in 1390, 610 and 325 MHz bands. We detected the 325 and 610 MHz radio counterparts of the SNR G353.6−0.7 (Nayana et al. 2017). We also determined the spectral indices of individual filaments and our values are consistent with the non-thermal radio emission. We compared the radio morphology with that of VHE emission. The peak in radio emission corresponds to the faintest feature in the VHE emission. We explain this anti-correlated emission in a possible leptonic origin of the VHE γ-rays.

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