scholarly journals Modeling the Local Bubble Using Multiple Supernova Remnants

1997 ◽  
Vol 166 ◽  
pp. 133-136
Author(s):  
R.K. Smith ◽  
D.P. Cox
Keyword(s):  
Interstellar Medium ◽  
Supernova Remnants ◽  
Local Interstellar Medium ◽  
Local Bubble ◽  
One Dimensional ◽  
X Ray ◽  
Hot Gas ◽  
Sky Survey ◽  
Non Equilibrium

AbstractWe have modeled the Local Bubble (LB) using a one-dimensional hydrocode (ODIN) that can simulate multiple supernova remnants, with non-equilibrium ion evolution and dust. Our model assumes that the local interstellar medium was a cool (104 K) gas approximately 5-10 Myr ago; it was then disturbed by 2 or 3 supernovae exploding within 20-30 pc of each other over a period of 2-4 million years. The LB is the leftover hot gas from these explosions. The model predicts the x-ray emission from such a bubble, as well as ionic abundances for hot gas ions such as O VI. These are compared to the soft x-ray data from the Wisconsin all-sky survey and the ROSAT PSPC.

scholarly journals Interstellar Scintillation of Radio Sources as a Probe for Investigations of the Local Interstellar Medium

1997 ◽  
Vol 166 ◽  
pp. 215-218
Author(s):  
N. Bochkarev ◽  
M. Ryabov
Keyword(s):  
Interstellar Medium ◽  
Small Scale ◽  
Radio Sources ◽  
Local Interstellar Medium ◽  
Star Formation Region ◽  
X Ray ◽  
Extragalactic Radio Sources ◽  
Hot Gas ◽  
The North ◽  
Scintillation Indices

AbstractA possibility of obtaining information on small scale inhomogeneities of the electron component of the local interstellar medium (LISM) is investigated using interstellar scintillations of extragalactic radio sources. We analyse Culgoora array observational data on variability of 190 extragalactic radio sources, covering most of the sky, at 80 and 160 MHz. The variability at time scales from 1 month to 15 years is interpreted as refractive interstellar scintillations in fast-moving nearby (less than 150 pc) hot gas near shock waves in the LISM. All-sky map of scintillation indices m averaged over 3–5 sources closest to one another shows several m maxima. Two of the 3 most pronounced maxima are probably connected with Loop I; the third one coincides with the soft X-ray (0.1–0.3 keV) background maximum near the South Galactic Pole. Other, less certain, m maxima probably correspond to the Orion star-formation region and to a soft X-ray maximum near the North Galactic Pole. The ”free-of-gas” tunnel in the direction l = 240° corresponds to low values of m. The estimated time scale of interstellar scintillations on the above-mentioned LISM structures is in agreement with that of the observed radio-source variations.

scholarly journals Non-Equilibrium Ionisation in Supernova Remnants - A Case Like Tycho - A case like Tycho

1988 ◽  
Vol 101 ◽  
pp. 137-140
Author(s):  
W. Brinkmann ◽  
H.H. Fink
Keyword(s):  
Chemical Composition ◽  
Interstellar Medium ◽  
Spectral Data ◽  
Spatial Resolution ◽  
Supernova Remnants ◽  
Great Care ◽  
X Ray ◽  
Non Equilibrium

AbstractX-ray observations of young supernova remnants (SNR) provide the most direct tool to study their evolution, their chemical composition, and their interaction with the interstellar medium. We will show for a SNR with the characteristics of Tycho that great care has to be taken in interpreting spectral data obtained with X-ray detectors with low spatial resolution.

scholarly journals 1/4 Ke V Diffuse Background and the Local Interstellar Medium

1989 ◽  
Vol 120 ◽  
pp. 536-536
Author(s):  
S.L. Snowden
Keyword(s):  
Interstellar Medium ◽  
Filling Factor ◽  
Thermal Emission ◽  
Mean Free Path ◽  
Physical Parameters ◽  
X Rays ◽  
Local Interstellar Medium ◽  
X Ray ◽  
Diffuse Background ◽  
X Ray Background

The 1/4 keV diffuse X-ray background (SXRB) is discussed in relation to the local interstellar medium (LISM). The most likely source for these soft X-rays is thermal emission from a hot diffuse plasma. The existence of a non-zero flux from all directions and the short ISM mean free path of these X-rays (1020HI cm-2), coupled with ISM pressure constraints, imply that the plasma has a local component and that it must, at least locally (nearest hundred parsecs), have a large filling factor. Our understanding of the geometry and physical parameters of the LISM is therefore directly tied to our understanding of the SXRB.

scholarly journals Chandra X-ray Observations of Dwarf Starburst Galaxies

2004 ◽  
Vol 217 ◽  
pp. 304-309
Author(s):  
Jürgen Ott ◽  
Fabian Walter ◽  
Elias Brinks ◽  
Ulrich Klein
Keyword(s):  
Interstellar Medium ◽  
Gravitational Potential ◽  
Thermal Plasma ◽  
Theoretical Models ◽  
Starburst Galaxies ◽  
Host Galaxy ◽  
X Ray ◽  
Hot Gas ◽  
Neutral Gas

We obtained X-ray observations for a sample of eight nearby dwarf starburst galaxies from the Chandra X-ray Observatory. Five galaxies of our sample show extended (size: 1-10 kpc), diffuse X-ray emission which can be attributed to a hot thermal plasma. This phase of the interstellar medium purportedly drives the expansion of supergiant shells. A comparison of the derived gas parameters with theoretical models reveals that the hot gas in principle is capable to escape from the gravitational potential of the host galaxy. However, the outflows appear to be contained in those cases where an extended envelope or massive tidal features of neutral gas exist.

scholarly journals Heating of the Interstellar Medium by Supernova Remnants

1983 ◽  
Vol 101 ◽  
pp. 385-392
Author(s):  
Donald P. Cox
Keyword(s):  
Interstellar Medium ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Low Density ◽  
The Sun ◽  
X Ray ◽  
Interstellar Material ◽  
X Ray Background

We observe the heating of interstellar material in young supernova remnants (SNR). In addition, when analyzing the soft X-ray background we find evidence for large isolated regions of apparently hot, low density material. These, we infer, may have been heated by supernovae. One such region seems to surround the Sun. This has been modeled as a supernova remnant viewed from within. The most reasonable parameters are ambient density no ~ 0.004 cm−3, radius of about 100 pc, age just over 105 years (Cox and Anderson 1982).

Distribution and Space Density of Soft X-ray Emitting Polars in the Solar Neighbourhood

1997 ◽  
Vol 166 ◽  
pp. 247-250
Author(s):  
H.-C. Thomas ◽  
K. Beuermann
Keyword(s):  
Cataclysmic Variables ◽  
Interstellar Space ◽  
X Rays ◽  
Absorption Column ◽  
Local Bubble ◽  
X Ray ◽  
Sky Survey ◽  
Imaging Telescope ◽  
Lower Limits ◽  
Typical Temperature

The ROSAT All Sky Survey (RASS) was the first one performed with an imaging telescope in the soft X-ray regime and has led to the discovery of numerous new objects whose emission is dominated by soft X-rays. Among these are white dwarfs and a subclass of the cataclysmic variables (CVs), the Polars or AM Herculis binaries. From a pre-ROSAT census of only 17, the number of known sources of this class has increased to some 55 (Beuermann and Thomas 1993, Beuermann 1997). Distances or lower limits to the distance are available for some 35 of these, based on the detection or non-detection of the TiO-Features in their optical red spectra. The derived distances range from below 100 pc up to ~ 600 pc, implying that many of these objects are located within the “Local Bubble” of low gas density in interstellar space. As the soft X-ray emission can be reasonably well represented by blackbody emission with a typical temperature of kTbb ≃ 25 eV, spectral fits to the ROSAT PSPC spectra from either the All-Sky-Survey (RASS) or from subsequent pointed ROSAT observations allow to determine the foreground absorption column density in the direction of the polars.

The soft X-ray diffuse background and the structure of the local interstellar medium

1980 ◽  
Vol 242 ◽  
pp. 987 ◽  
Author(s):  
P. M. Fried ◽  
J. A. Nousek ◽  
W. T. Sanders ◽  
W. L. Kraushaar
Keyword(s):  
Interstellar Medium ◽  
Local Interstellar Medium ◽  
X Ray ◽  
Diffuse Background

scholarly journals High Resolution X-ray Images of Puppis a and IC 443

1983 ◽  
Vol 101 ◽  
pp. 289-293
Author(s):  
R. Petre ◽  
C. R. Canizares ◽  
P. F. Winkler ◽  
F. D. Seward ◽  
R. Willingale ◽  
...  
Keyword(s):  
High Resolution ◽  
Interstellar Medium ◽  
Molecular Cloud ◽  
Supernova Remnants ◽  
Surface Brightness ◽  
Middle Aged ◽  
X Ray ◽  
Giant Molecular Cloud

We present soft X-ray photomosaic images of two supernova remnants, Puppis A and IC 443, constructed from a series of exposures by the Einstein imaging instruments. The complex morphologies displayed in these images reflect the interaction between “middle-aged” supernova remnants and various components of the interstellar medium. Surface brightness variations across Puppis A suggest that inhomogeneities on scales from 0.2 to 30 pc are present in the interstellar medium, while the structure of IC 443 is apparently dominated by the interaction between the remnant and a giant molecular cloud.

scholarly journals IRAS Observations of Collisionally Heated Dust in Large Magellanic Cloud Supernova Remnants

1988 ◽  
Vol 101 ◽  
pp. 383-386
Author(s):  
James R. Graham ◽  
A. Evans ◽  
J.S. Albinson ◽  
M.F. Bode ◽  
W.P.S. Meikle
Keyword(s):  
Interstellar Medium ◽  
Supernova Remnants ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Substantial Fraction ◽  
X Ray ◽  
Ir Sources ◽  
Atomic Cooling ◽  
Dust Grain ◽  
Ir Emission

AbstractIRAS additional observations show that luminous (104−105 L⊙) far-IR sources are associated with the Large Magellanic Cloud (LMC) supernova remnants N63A, N49, N49B, and N186D. Comparison of the IRAS and X-ray data shows that a substantial fraction of the IR emission from three of the SNRs can be accounted for by collisionally heated dust. The ratio of dust-grain cooling to total atomic cooling is ~10 in X-ray emitting gas (T~106 K). We show why dust cooling does not dominate, but probably speeds SNR evolution in an inhomogeneous interstellar medium.

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