Initial Blast Wave Research Articles

Supersonic jet by blast wave focusing

A supersonic jet of Mach number M = 4.5 in air is produced experimentally at the apex of a miniature 150 × 50 × 5 mm converging section with a 2 × 5 mm opening by the principle of blast wave amplification through focusing. An initial plane blast wave of M = 2.4 in the convergence section is generated by the exploding wire technique. The profile of the convergence section is specially tailored to smoothly transform a plane blast wave into a perfectly cylindrical arc, imploding at the apex of the section. The cylindrical form of the imploding shock delivers maximum shock amplification in the two-dimensional test section and maximum subsequent jet flow velocity behind the shock front. Blast wave propagation in the convergence chamber as well as jet generation through a 2 mm opening at the apex into the adjacent exhaust chamber is optically captured by a high-speed camera using the shadowgraph method. Visualizing the flow provided a distinct advantage not only for obtaining detailed information on the flow characteristics but also for validating the numerical scheme which further enhanced the analysis. Experimental images together with the numerical analysis deliver detailed information on the blast wave propagation and focusing as well as subsequent jet initiation and development. One of the main advantages of the described method apart from being simple and robust is the effective focusing of low initial input energy levels of just around 500 Joules, resulting in production of supersonic jets in a small confined chamber.

Ocular biomechanics due to ground blast reinforcement

Background and objectiveBomb blast injuries exerts a shearing force on the air-tissue interfaces, causing devastating ocular injury from the blast wave. Improvised explosive devices (IEDs) are usually placed at different heights from the ground to induce more severe injury through ground blast reinforcement (GBR). However, there is still a lack of knowledge of the role of GBR and IED height from the ground on ocular biomechanics, and how they can affect the intraocular pressure (IOP) in the eye. This study aimed to estimate the IOP due to frontal IED explosion at different heights from the ground using a fluid-structure interaction model with and without GBR effects. MethodsA 2 kg IED was placed within 5 m of the victim at 5 different heights from the ground, including 0, 0.42, 0.85, 1.27, and 1.70 m. Two different blast formulations were used to simulate the IED explosion: (a) spherical airburst, with no amplification of the initial shock wave due to interaction with the ground-surface, and (b) hemispherical surface-burst, where the initial blast wave is immediately reflected and reinforced by the ground (GBR). ResultsResults revealed that the blast wave due to GBR reaches to the skull prior to the IED blast itself. The GBR also reached to the skull ∼ 0.6 ms earlier when the IED was on the ground compared to the height of 1.70 m. The highest and lowest IOPs of ∼ 17,000 and ∼ 15,000 mmHg were observed at the IED heights of 1.70 and 0 m from the ground considering GBR. However, when the role of the GBR is ignored, IOP of ∼ 9,000 mmHg was observed regardless of the IED height from the ground. The deformation in the apex of the cornea was higher when considering the GBR (∼ 0.75 cm) versus no GBR (∼ 0.65 cm). Considering GBR led to higher stresses and strains in the sclera. ConclusionsWhen the role of GBR was ignored, the results showed similar patterns and magnitudes of stresses and deformations in the skull and eye regardless of the height of the IED from the ground, which was not the case when GBR was considered. The findings of this study suggest the critical role of GBR in ocular blast simulations.

Modeling the mixed-morphology supernova remnant IC 443

Context. The morphology and the distribution of material observed in supernova remnants (SNRs) reflect the interaction of the supernova (SN) blast wave with the ambient environment, the physical processes associated with the SN explosion, and the internal structure of the progenitor star. IC 443 is a mixed-morphology (MM) SNR located in a quite complex environment: it interacts with a molecular cloud in the northwestern and southeastern areas and with an atomic cloud in the northeast. Aims. In this work, we aim to investigate the origin of the complex morphology and multi-thermal X-ray emission observed in SNR IC 443 through the study of the effect of the inhomogeneous ambient medium in shaping its observed structure and an exploration of the main parameters characterizing the remnant. Methods. We developed a 3D hydrodynamic (HD) model for IC 443, which describes the interaction of the SNR with the environment, parametrized in agreement with the results of the multi-wavelength data analysis. We performed an ample exploration of the parameter space describing the initial blast wave and the environment, including the mass of the ejecta, the energy and position of the explosion, as well as the density, structure, and geometry of the surrounding clouds. From the simulations, we synthesized the X-ray emission maps and spectra and compared them with actual X-ray data collected by XMM-Newton. Results. Our model explains the origin of the complex X-ray morphology of SNR IC 443 in a natural way, with the ability to reproduce, for the first time, most of the observed features, including the centrally-peaked X-ray morphology (characteristic of MM SNRs) when considering the origin of the explosion at the position where the pulsar wind nebula CXOU J061705.3+222127 was at the time of the explosion. In the model that best reproduces the observations, the mass of the ejecta and the energy of the explosion are ~7 M⊙ and ~1 × 1051 erg, respectively. From the exploration of the parameter space, we find that the density of the clouds is n > 300 cm−3 and that the age of SNR IC 443 is ~8000 yr. Conclusions. The observed inhomogeneous ambient medium is the main property responsible for the complex structure and the X-ray morphology of SNR IC 443, resulting in a very asymmetric distribution of the ejecta due to the off-centered location of the explosion inside the cavity formed by the clouds. It can be argued that the centrally peaked morphology (typical of MM SNRs) is a natural consequence of the interaction with the complex environment. A combination of high resolution X-ray observations and accurate 3D HD modeling is needed to confirm whether this scenario is applicable to other MM SNRs.

Ground-based exploding balloon noise propagating over a grass-covered field

With ground-based, impulsive acoustic sources, the initial blast wave can be followed by additional noise that is difficult to interpret. As outlined by Embelton [J. Acoust. Soc. Am. 100 (1996)], a porous ground can lead to creeping, ground, and surface waves. In a recent test on a grass-covered field, the blast noise from exploding balloons had evidence of a secondary arrival that in some cases was larger than the blast wavefront. The balloons were filled with oxy-acetylene gas and placed on the ground or in holes. The balloons were ignited, and the sound from the resulting explosions were measured at distances of 100, 130, and 160 m. At each of these stations, microphones were placed at four heights: 0.01, 1.2, 2.4, and 3.6 m. For every explosion, the blast wave amplitude increases with height, while the secondary arrival amplitude decreases with height. This variation in height can help identify the type of wave responsible for the secondary arrival. For example,the amplitude of surface waves propagating over grass exponentially decay with height. This study will help distinguish different types of acoustic signals produced by ground-based explosions, such as the Volcano Hazards Workshop in 2018.With ground-based, impulsive acoustic sources, the initial blast wave can be followed by additional noise that is difficult to interpret. As outlined by Embelton [J. Acoust. Soc. Am. 100 (1996)], a porous ground can lead to creeping, ground, and surface waves. In a recent test on a grass-covered field, the blast noise from exploding balloons had evidence of a secondary arrival that in some cases was larger than the blast wavefront. The balloons were filled with oxy-acetylene gas and placed on the ground or in holes. The balloons were ignited, and the sound from the resulting explosions were measured at distances of 100, 130, and 160 m. At each of these stations, microphones were placed at four heights: 0.01, 1.2, 2.4, and 3.6 m. For every explosion, the blast wave amplitude increases with height, while the secondary arrival amplitude decreases with height. This variation in height can help identify the type of wave responsible for the secondary arrival. For example,the amplitude of surface waves propagati...

Preliminary attempts to isolate ground-radiated noise from exploding balloons

Seismo-acoustic coupling occurs when seismic wave propagation creates air-borne acoustic signals. Research is ongoing to determine methods to distinguish between sound due to seismo-acoustic coupling and purely air-borne transmission. In a field experiment, we detonated 17 in. balloons filled with a stoichiometric oxy-acetylene mix placed both on and in the ground. We attempted to isolate ground-radiated waves by constructing a portable soundproof box to deaden air-borne sound wave. The box was constructed from mass-loaded vinyl, soundproofing composite board, liquid nails, and Green Glue. This design incorporated soundproofing through decoupling, absorption, and insulation techniques. Signals observed from a microphone placed in the box are compared with those obtained on microphones outside the box at various heights. The initial blast wave was not evident inside the box. However, the loudest sound measured in the box matches a subsequent portion of signals on microphones near the ground. Testing in a reverberation chamber is done to measure the frequency response in the transmission loss through the box. These results could suggest a viable technique for isolating ground-borne acoustic waves, which could be useful in experiments where calculating the coupling effect is impractical.

A MCREXS modelling approach for the simulation of a radiological dispersal device

Assessing the risks of radioactive dose in a radiological dispersal device (RDD) attack requires knowledge of how the radiological materials will be spread through the air surrounding the site of the detonation. Two essential parts of the accurate prediction of the behaviour of this dispersion are a characterization of the initial cloud size, directly after the blast, and detailed modelling of the behaviour of different size particulates. Capturing the transport of contaminants from the initial blast wave is integral to achieving accurate predictions, especially for regions where the blast dynamics dominates, but performing such calculations over a wide range of particle sizes and spatial scales is computationally challenging. Formulation of efficient computational techniques for such advanced models is required to provide predictive tools useful to first responders and emergency planners. In this work, a Multi-Cloud Radiological EXplosive Source (MCREXS) modelling approach for RDD is investigated. This approach combines a stochastic, particle-based, mechanistic model with a standard atmospheric dispersion model. The former is used to characterize the distribution of radioactive material near the source of the explosion, where the blast wind effects are important, while the latter is used to model the transport of the contaminant in the environment over large areas. The particle transport in the near-field of the explosion site is computed based on a Lagrangian description of the particle phase and a reconstructed-Eulerian field for the carrier phase. The information inferred from this physics-based model is then used as a starting point for a subsequent standard Gaussian puff model to calculate the dispersion of the radioactive contaminant. The predictive capabilities of the MCREXS model are assessed against the 2012 DRDC Suffield full-scale RDD experiments. The results demonstrate improved predictions relative to those performed using only a Gaussian puff calculation from an empirical initial cloud distribution.

Primary blast-induced traumatic brain injury: lessons from lithotripsy

Traumatic injury caused by explosive or blast events is traditionally divided into four mechanisms: primary, secondary, tertiary, and quaternary blast injury. The mechanisms of blast-induced traumatic brain injury (bTBI) are biomechanically distinct and can be modeled in both in vivo and in vitro systems. The primary bTBI injury mechanism is associated with the response of brain tissue to the initial blast wave. Among the four mechanisms of bTBI, there is a remarkable lack of information regarding the mechanism of primary bTBI. On the other hand, 30 years of research on the medical application of shock waves (SWs) has given us insight into the mechanisms of tissue and cellular damage in bTBI, including both air-mediated and underwater SW sources. From a basic physics perspective, the typical blast wave consists of a lead SW followed by shock-accelerated flow. The resultant tissue injury includes several features observed in primary bTBI, such as hemorrhage, edema, pseudo-aneurysm formation, vasoconstriction, and induction of apoptosis. These are well-described pathological findings within the SW literature. Acoustic impedance mismatch, penetration of tissue by shock/bubble interaction, geometry of the skull, shear stress, tensile stress, and subsequent cavitation formation are all important factors in determining the extent of SW-induced tissue and cellular injury. In addition, neuropsychiatric aspects of blast events need to be taken into account, as evidenced by reports of comorbidity and of some similar symptoms between physical injury resulting in bTBI and the psychiatric sequelae of post-traumatic stress. Research into blast injury biophysics is important to elucidate specific pathophysiologic mechanisms of blast injury, which enable accurate differential diagnosis, as well as development of effective treatments. Herein we describe the requirements for an adequate experimental setup when investigating blast-induced tissue and cellular injury; review SW physics, research, and the importance of engineering validation (visualization/pressure measurement/numerical simulation); and, based upon our findings of SW-induced injury, discuss the potential underlying mechanisms of primary bTBI.

Efficacy of visor and helmet for blast protection assessed using a computational head model

Head injury resulting from blast exposure has been identified as a challenge that may be addressed, in part, through improved protective systems. Existing detailed head models validated for blast loading were applied to investigate the influence of helmet visor configuration, liner properties, and shell material stiffness. Response metrics including head acceleration and intracranial pressures (ICPs) generated in brain tissue during primary blast exposure were used to assess and compare helmet configurations. The addition of a visor was found to reduce peak head acceleration and positive ICPs. However, negative ICPs associated with a potential for injury were increased when a visor and a foam liner were present. In general, the foam liner material was found to be more significant in affecting the negative ICP response than positive ICP or acceleration. Shell stiffness was found to have relatively small effects on either metric. A strap suspension system, modeled as an air gap between the head and helmet, was more effective in reducing response metrics compared to a foam liner. In cases with a foam liner, lower-density foam offered a greater reduction of negative ICPs. The models demonstrated the “underwash” effect in cases where no foam liner was present; however, the reflected pressures generated between the helmet and head did not translate to significant ICPs in adjacent tissue, when compared to peak ICPs from initial blast wave interaction. This study demonstrated that the efficacy of head protection can be expressed in terms of load transmission pathways when assessed with a detailed computational model.

Aeroelastic response of rocket nozzles to asymmetric thrust loading

The aeroelastic response of rocket nozzles subjected to combined axial thrust and side loads is investigated using a particular computational technique. The technique uses two-way “loose” coupling between an accurate flow solver and an accurate structural-dynamics solver to accurately capture the behavior of the internal flow, the behavior of the nozzle wall, and the interactions between the fluid-dynamic and structural-dynamic phenomena. It is shown that the technique captures the fluid-dynamic phenomena that are known to contribute to nozzle side loads, including the asymmetry in the propagation of the initial blast wave, the asymmetry in the separation lines, the pressure pulsations at the separation lines, the transition of separated flow patterns, and various flow instabilities. It is also shown that the computational technique couples the fluid-dynamic and the structural-dynamic solutions with an accuracy and a resolution that are sufficient for accurate prediction of the aeroelastic response modes in the system. The fluid-dynamics solver is validated for shock-induced flow separations in a sub-scale J-2S nozzle, while the structural-dynamic solver is validated for a typical dynamic response in a rocket nozzle. The two-way loose coupling methodology is validated for the flutter of a flat plate in supersonic flow, and the validation results are discussed and assessed with respect to the fitness of the computational technique for the prediction of the aeroelastic response of typical actual nozzle configurations. Finally, the side loads are computed for a J-2S nozzle with rigid walls and with flexible walls, and the results for the two types of walls are analyzed and compared. It is found that allowing aeroelastic coupling significantly affects the response of the nozzle and the predicted side loads. It is speculated that the computational technique investigated in this work combines all the elements required to accurately predict and simulate the aeroelastic response of a rocket nozzle to non-symmetric thrust, and that such a technique can be used to study and investigate side load phenomena in rocket nozzles in detail and also as a design tool for rocket nozzles. The technique is also speculated to be effective and appropriate for other fluid–structure interaction problems within an appropriate range of aeroelastic regimes.

Clinical relevance of blast-related traumatic brain injury

The global war against terrorism has created new challenges for neurosurgeons, craniofacial surgeons and maxillofacial surgeons; United States military operations in Iraq and Afghanistan have resulted in the greatest incidence of head trauma since the Vietnam conflict. The more frequent use of improvised explosive devices (IED), in conjunction with increased survival from improved body armor and battlefield medicine, has contributed to the increasing number of craniomaxillofacial injuries and consequent head trauma [28]. IEDs usually contain an explosive that, during detonation, is converted into a gas that rapidly expands and forms a high-pressure wave [4]. This blast overpressure wave travels at supersonic speeds and causes primary blast injury. The subsequent blast wind that follows the initial blast wave can propel objects, leading to further harm [7, 29]. The effect of a primary blast wave on the brain remains poorly understood despite the various models and computer simulations used to predict different mechanisms of injury [5, 27]. Because 59% of the service members in Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) suffered from TBI [21], a better understanding of mechanisms underlying primary blast injury and the establishment of guidelines of care are warranted. Persistent and debilitating symptoms are often associated with mild traumatic brain injury [24], underscoring the need for improved diagnostic and therapeutic modalities. Diffuse axonal injury (DAI) is widely hypothesized to be a principle mechanism of damage and the cause of persistent cognitive defects after traumatic brain injury (TBI). Angular forces can cause shearing or stretching of axons, leading to impaired axonal transport and swelling [9]. However, further elucidation of the pathological mechanism behind blast injury and determining the ideal diagnostic method to identify this condition may help lead to greater protection for military personnel and treatments for those already suffering from this disease. The majority (85%) of reported TBI cases are undetectable with imaging (computed tomography (CT) and magnetic resonance imaging (MRI) are usually insensitive to its characteristic small lesions [1, 13]) and are classified as mild [2, 25] based on the Department of Defense (DoD) screening criteria. The DoD defines mild TBI as loss of consciousness, amnesia, mental status alteration at time of injury, and/or focal neurological deficit or peri-injury confusion/disorientation in a patient with a Glasgow Coma Scale (GCS) score of 13–15 [18]. Once diagnosed, mild TBI is a treatable disease typically associated with a very favorable prognosis [15]. As a result, the recently published results by Mac Donald and colleagues have created a sense of cautious optimism regarding the use of diffusion tensor imaging (DTI) in detecting structural brain damage in blast-exposed patients suffering from mild TBI. In their study, Mac Donald et al. enrolled 63 patients, ages 19–58, from a screened population of 122 service members. The primary goal was to establish whether or not traumatic axonal injury is a primary feature of human blastG. Appelboom : J. Han : S. Bruce : E. S. Connolly Jr. Department of Neurological Surgery, The Neurological Institute, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA

Mechanisms of Primary Blast-Induced Traumatic Brain Injury: Insights from Shock-Wave Research

Traumatic brain injury caused by explosive or blast events is traditionally divided into four phases: primary, secondary, tertiary, and quaternary blast injury. These phases of blast-induced traumatic brain injury (bTBI) are biomechanically distinct and can be modeled in both in vivo and in vitro systems. The primary bTBI injury phase represents the response of brain tissue to the initial blast wave. Among the four phases of bTBI, there is a remarkable paucity of information about the cause of primary bTBI. On the other hand, 30 years of research on the medical application of shockwaves (SW) has given us insight into the mechanisms of tissue and cellular damage in bTBI, including both air-mediated and underwater SW sources. From a basic physics perspective, the typical blast wave consists of a lead SW followed by supersonic flow. The resultant tissue injury includes several features observed in bTBI, such as hemorrhage, edema, pseudoaneurysm formation, vasoconstriction, and induction of apoptosis. These are well-described pathological findings within the SW literature. Acoustic impedance mismatch, penetration of tissue by shock/bubble interaction, geometry of the skull, shear stress, tensile stress, and subsequent cavitation formation, are all important factors in determining the extent of SW-induced tissue and cellular injury. Herein we describe the requirements for the adequate experimental set-up when investigating blast-induced tissue and cellular injury; review SW physics, research, and the importance of engineering validation (visualization/pressure measurement/numerical simulation); and, based upon our findings of SW-induced injury, discuss the potential underlying mechanisms of primary bTBI.

Mitigation of TNT and Destex explosion effects using water mist

The effects water mist has on the overpressures produced by the detonation of 50 lb equivalent of high explosives (HE) TNT and Destex in a chamber is reported. The overpressures for each charge density were measured with and without mist preemptively sprayed into the space. A droplet analyzer was placed in the chamber prior to the detonation experiments to characterize the water mist used to mitigate the explosion overpressures. The impulse, initial blast wave, and quasi-static overpressure measured in the blast mitigation experiments were reduced by as much as 40%, 36%, 35% for TNT and 43%, 25%, 33% for Destex when water mist was sprayed 60 s prior to detonation at a concentration of 70 g/m 3 and droplet Sauter Mean Diameter (SMD) 54 μm. These results suggest that current water mist technology is a potentially promising concept for the mitigation of overpressure effects produced from the detonation of high explosives.

Mechanism and emergency management of blast eye/orbital injuries

Nonconventional combat is ever-present around the world. In recent years, there has been an unprecedented increase in suicides, homicides and insurgents using improvised explosive devices such as improvised explosive devices, land mines, rocket-propelled grenades (RPG-7 to -29), thermobaric ‘enhanced-blast explosives’ and explosive-formed projectiles. All of these devices have been shown to dramatically increase eye/orbital injuries. The pathophysiology, biophysics and mechanism of primary and secondary blast-wave front effects are primary causative factors of war-induced eye injuries. This review aims to reappraise eye/orbit blast injuries, thus helping in their management and protection. Blast ocular orbital trauma includes rupture of the globe, serous retinitis, hyphema, corneoscleral lacerations, penetrating eyeball, traumatic cataracts and injury of the optic nerve, nasal–orbital–ethmoidal injuries, brain injury, maxillofacial crushed middle-third fractures and associated multisystem injuries. If the eye is significantly damaged as a result of an initial blast wave, such that it cannot be properly repaired, primary enucleation may be a reasonable option. Another instance where enucleation is possible is if a patient with a significant injury cannot obtain adequate follow-up and be monitored for signs of sympathetic ophthalmia, or in instances where other injuries prevent the patient from actively participating in the decision to save or enucleate an eye in the first 14 days after injury; as in associated head injury. Wearing a visor can protect against eye/orbital damage caused by foreign body penetration and will provide reasonable protection against blast induced eye/orbital injuries.

Numerical prediction of concrete slab response to blast loading

In this paper, a dynamic plastic damage model for concrete material has been employed to estimate responses of both an ordinary reinforced concrete slab and a high strength steel fibre concrete slab subjected to blast loading. In the concrete material model, the strength envelope is a damage-based modified piece-wise Drucker–Prager model; the strain rate effect on tension and compression are considered separately; the damage variable is based on Mazars’ damage model, which is a combination of tensile and compressive damage. The equation of state (EOS) is also a combination of the porous and solid EOS of concrete with different forms for tension and compression states. The interaction between the blast wave and the concrete slab is considered in the 3D simulation. In the first stage, the initial detonation and blast wave propagation is modelled in a 2D simulation before the blast wave reaches the concrete slab, then the results obtained from the 2D calculation are remapped to a 3D model. The calculated blast load is compared with that obtained from TM5-1300. The numerical results of the concrete slab response are compared with the explosive tests carried out in the Weapons System Division, Defence Science and Technology Organisation, Department of Defence, Australia. Repetitive applications of blast loading on slabs are also simulated and the results compared with test data.

Soft X‐Ray Spectroscopy of the Cygnus Loop Supernova Remnant

The Cygnus X-ray Emission Spectroscopic Survey (CyXESS) sounding rocket payload was launched from White Sands Missile Range on 2006 November 20 and obtained a high resolution spectrum of the Cygnus Loop supernova remnant in the soft X-rays. The novel X-ray spectrograph incorporated a wire-grid collimator feeding an array of gratings in the extreme off-plane mount which ultimately dispersed the spectrum onto Gaseous Electron Multiplier (GEM) detectors. This instrument recorded 65 seconds of usable data between 43-49.5 \AA in two prominent features. The first feature near 45 \AA is dominated by the He-like triplet of \ion{O}{7} in second order with contributions from \ion{Mg}{10} and \ion{Si}{9}-\ion{Si}{12} in first order, while the second feature near 47.5 \AA is first order \ion{S}{9} and \ion{S}{10}. Fits to the spectra give an equilibrium plasma at $\log(T)=6.2$ ($kT_e=0.14$ keV) and near cosmic abundances. This is consistent with previous observations, which demonstrated that the soft x-ray emission from the Cygnus Loop is dominated by interactions between the initial blast wave with the walls of a precursor formed cavity surrounding the Cygnus Loop and that this interaction can be described using equilibrium conditions.

A Rebrightening of the Radio Nebula Associated with the 2004 December 27 Giant Flare from SGR 1806-20

The 2004 December 27 giant γ-ray flare detected from the magnetar SGR 1806-20 created an expanding radio nebula that we have monitored with the Australia Telescope Compact Array and the Very Large Array. These data indicate that there was an increase in the observed flux ~25 days after the initial flare that lasted for ~8 days, which we believe is the result of ambient material swept up and shocked by this radio nebula. For a distance to SGR 1806-20 of 15 kpc, using the properties of this rebrightening, we infer that the initial blast wave was dominated by baryonic material of mass M 1024.5 g. For an initial expansion velocity v ~ 0.7c (as derived in an accompanying paper), we infer that this material had an initial kinetic energy E 1044.5 ergs. If this material originated from the magnetar itself, it may have emitted a burst of ultra-high-energy (E > 1 TeV) neutrinos far brighter than that expected from other astrophysical sources.

SNe heating and the chemical evolution of the intra-cluster medium

We compute the chemical and thermal history of the intra-cluster medium in rich and poor clusters under the assumption that supernovae (I, II) are the major responsible both for the chemical enrichment and the heating of the intra-cluster gas. We assume that only ellipticals and S0 galaxies contribute to the enrichment and heating of the intra-cluster gas through supernova driven winds and explore several prescriptions for describing the feedback between supernovae and the interstellar medium in galaxies. We then integrate the chemical and energetical contributions from single cluster galaxies over the cluster luminosity function and derive the variations of these quantities as functions of the cosmic time. We reach the following conclusions: (i) while type II supernovae dominates the chemical enrichment and energetics inside the galaxies, type Ia supernovae play a predominant role in the intra-cluster medium, (ii) galaxy models, which reproduce the observed chemical abundances and abundance ratios in the intra-cluster medium, predict a maximum of 0.3–0.4 keV per particle of energy input, a result obtained by assuming that type Ia supernovae contribute 100% of their initial blast wave energy whereas type II supernovae contribute only a few percents of their initial energy.

Copernicus - Soft X-ray emission from certain features of the Cygnus Loop

view Abstract Citations (14) References (21) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Copernicus: soft X-ray emission from certain features of the Cygnus Loop. Charles, P. A. ; Culhane, J. L. ; Zarnecki, J. C. Abstract Observations made with the MSSL 0.5-1.5 keV X-ray telescope on board Copernicus of several features of previous X-ray maps of the Cygnus Loop, including the prominent filaments (NGC 6992-5) in the northeastern part and a region in the northern part containing some scattered filaments and a small peak in the radio emission, are discussed. A thermal continuous spectrum is used to fit the satellite data to the X-ray maps, and emission fluxes and spectra are calculated for the filamentary regions. The results tend to confirm the existence of the previously mapped bright X-ray emitting regions, and support Stevens' interpretation that an encounter between the initial blast wave from the supernova and an inhomogeneous interstellar medium has caused the discrepancy between the observed optical filament velocities and the implied shock velocities necessary for the observed X-ray emission. Publication: The Astrophysical Journal Pub Date: February 1975 DOI: 10.1086/181734 Bibcode: 1975ApJ...196L..19C Keywords: Astronomical Maps; Cygnus Constellation; Oao 3; Satellite Observation; X Ray Sources; Interstellar Radiation; Radio Emission; Radio Spectra; Satellite-Borne Instruments; Spaceborne Astronomy; Spaceborne Telescopes; Supernovae; Thermal Radiation; X Ray Telescopes; Astrophysics full text sources ADS |