Diffuse Ionized Gas in the β CMa Tunnel

1997 ◽  
Vol 166 ◽  
pp. 173-176
Author(s):  
Olivier Dupin ◽  
Cécile Gry
Keyword(s):  
Interstellar Medium ◽  
Low Density ◽  
Ionized Gas ◽  
Local Bubble ◽  
Diffuse Ionized Gas ◽  
Main Components ◽  
Collisional Ionization ◽  
Dust Grain

AbstractWe present HST observations of the interstellar medium toward the star β CMa known to be located in a low density extension of the Local Bubble. Most of the matter in the sight-line is ionized and clumped in two main components. One of them, as well as one of the components detected toward ϵ CMa, is mostly ionized and only slightly depleted. Their ionization ratios are compatible with collisional ionization at T~25 000 K. These clouds could have been ionized by shocks related to the Local Bubble creation and also responsible of some dust grain sputtering.

scholarly journals Study of the LISM Using Pulsar Scintillation

1997 ◽  
Vol 166 ◽  
pp. 211-214
Author(s):  
N.D.R. Bhat ◽  
Y. Gupta ◽  
A.P. Rao
Keyword(s):  
Interstellar Medium ◽  
Radio Telescope ◽  
Density Fluctuations ◽  
Solar Neighborhood ◽  
Dispersion Measure ◽  
Low Density ◽  
Local Interstellar Medium ◽  
Local Bubble ◽  
Scattering Material ◽  
Scattering Strength

AbstractWe present here the results from an extensive scintillation study of twenty pulsars in the dispersion measure (DM) range 3 – 35 pc cm−3 carried out using the Ooty Radio Telescope, to investigate the distribution of ionized material in the local interstellar medium (LISM). Our analysis reveals several anomalies in the scattering strength, which suggest that the distribution of scattering material in the solar neighborhood is not uniform. Our model suggests the presence of a low density bubble surrounded by a shell of much higher density fluctuations. We are able to put some constraints on geometrical and scattering properties of such a structure, and find it to be morphologically similar to the local bubble known from other studies.

Radio Polarimetric Imaging of the Interstellar Medium: Magnetic Field and Diffuse Ionized Gas Structure near the W3/W4/W5/HB 3 Complex

1999 ◽  
Vol 514 (1) ◽  
pp. 221-231 ◽  
Author(s):  
A. D. Gray ◽  
T. L. Landecker ◽  
P. E. Dewdney ◽  
A. R. Taylor ◽  
A. G. Willis ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Interstellar Medium ◽  
Ionized Gas ◽  
Diffuse Ionized Gas ◽  
Polarimetric Imaging

scholarly journals Interaction of the Local Bubble with its environment

1997 ◽  
Vol 166 ◽  
pp. 287-296
Author(s):  
Roland Egger
Keyword(s):  
High Temperature ◽  
Low Density ◽  
Ionized Gas ◽  
Local Bubble ◽  
Neutral Gas ◽  
Unique Object ◽  
Gum Nebula ◽  
Two Bubbles

AbstractThe Local Bubble (LB), a volume of roughly 100 pc radius filled with ionized gas of high temperature and low density, is not a unique object. It is obviously surrounded by several interstellar bubbles of similar properties. Some of them are as close as to undergo interaction with the LB. Our most prominent neighbour is the Loop I superbubble formed by the Sco-Cen OB association. It is shown that this huge shell is in collision with our Local Bubble. The product of this interaction is an annular cloud of dense neutral gas at the boundary between the two bubbles. Other examples for close neighbouring bubbles are the Gum nebula, the Eridanus bubble and possibly the two radio loops II and III.

scholarly journals The Local Bubble and Beyond: Summary

1997 ◽  
Vol 166 ◽  
pp. 563-580 ◽  
Author(s):  
Christopher F. McKee
Keyword(s):  
Interstellar Medium ◽  
Galactic Plane ◽  
Low Density ◽  
The Sun ◽  
Local Bubble ◽  
Current State ◽  
The Galaxy ◽  
Theoretical Discovery ◽  
Gaseous Halo

Lyman Spitzer, Jr, the founder of modern studies of the interstellar medium (ISM), passed away March 31, 1997. This conference occurred shortly thereafter and is dedicated to his memory. While many of his contributions underlie the work that was discussed at this meeting, one paper stands out in particular: his theoretical “discovery” of the hot gaseous halo of the Galaxy based on the need to confine the clouds of H I observed above the Galactic plane (Spitzer 1956). We now know that much of the ISM within about 100 pc of the Sun is largely filled by very low density gas, which is generally inferred to be hot, and as a result this region is termed the Local Bubble (Cox and Reynolds 1987). This conference was convened to establish the current state of our knowledge of the Local Bubble, both observational and theoretical, and its relation to the rest of the ISM. Because it is nearby, the Local Bubble is a laboratory for interstellar astrophysics, making the dedication to Spitzer’s memory particularly appropriate.

scholarly journals GASP XXXV: Characteristics of the Diffuse Ionised Gas in Gas-stripped Galaxies

2021 ◽  
Vol 922 (2) ◽  
pp. 131
Author(s):  
Neven Tomičić ◽  
Benedetta Vulcani ◽  
Bianca M. Poggianti ◽  
Ariel Werle ◽  
Ancla Müller ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Spatial Scales ◽  
Dense Gas ◽  
Gas Stripping ◽  
Ionized Gas ◽  
Massive Galaxies ◽  
Star Forming ◽  
Diffuse Ionized Gas ◽  
The Difference ◽  
And Control

Abstract Diffuse ionized gas (DIG) is an important component of the interstellar medium that can provide insights into the different physical processes affecting the gas in galaxies. We utilize optical IFU observations of 71 gas-stripped and control galaxies from the Gas Stripping Phenomena in galaxies (GASP) survey, to analyze the gas properties of dense ionized gas and DIG, such as metallicity, ionization parameter log(q), and the difference between the measured log[O i]/Hα and the value predicted by star-forming models given the measured log[Oiii]/Hβ (Δ log[O i]/Hα). We compare these properties at different spatial scales, among galaxies at different gas-stripping stages, and between disks and tails of the stripped galaxies. The metallicity is similar between the dense gas and DIG at a given galactocentric radius. The log(q) is lower for DIG compared to dense gas. The median values of log(q) correlate best with stellar mass and the most massive galaxies show an increase in log(q) toward their galactic centers. The DIG clearly shows higher Δ log[O i]/Hα values compared to the dense gas, with much of the spaxels having LIER/LINER-like emission. The DIG regions in the tails of highly stripped galaxies show the highest Δ log[O i]/Hα, exhibit high values of log(q), and extend to large projected distances from star-forming areas (up to 10 kpc). We conclude that the DIG in the tails is at least partly ionized by a process other than star formation, probably by mixing, shocks, and accretion of inter-cluster and interstellar medium gas.

scholarly journals The Interstellar Gas in the Line of Sight to ϵ Canis Majoris

1996 ◽  
Vol 152 ◽  
pp. 299-299
Author(s):  
C. Gry ◽  
L. Lemonon ◽  
A. Vidal-Madjar ◽  
M. Lemoine ◽  
R. Ferlet
Keyword(s):  
Interstellar Medium ◽  
Hubble Space Telescope ◽  
Line Of Sight ◽  
Interstellar Gas ◽  
Local Bubble ◽  
Gas Density ◽  
Neutral Gas ◽  
Turbulence Velocity ◽  
Main Components ◽  
Local Cloud

We analyse Hubble Space Telescope GHRS observations of the interstellar medium in the direction to ϵ CMa, the strongest EUV source in the sky located 200 pc away in a region deficient in neutral gas. We show that the neutral gas density is the lowest yet measured in a galactic sight-line. The line of sight contains three main components among which the Local Cloud, and we derive their column densities, their velocity their temperature and their turbulence velocity. We discuss the ionization of the Local Cloud and we show that we detect the conductive interface between diffuse local cloud and the hot local bubble.

scholarly journals Diffuse Ionized Gas in Nearby Galaxies

1991 ◽  
Vol 144 ◽  
pp. 223-232
Author(s):  
R.A.M. Walterbos
Keyword(s):  
Interstellar Medium ◽  
Spectral Characteristics ◽  
High Ratio ◽  
Radio Continuum ◽  
Ionized Gas ◽  
Star Forming ◽  
Star Forming Regions ◽  
Diffuse Ionized Gas ◽  
External Galaxies ◽  
Nearby Galaxies

We discuss the distribution and spectral characteristics of diffuse ionized gas in nearby galaxies. The existence of this elusive component of the interstellar medium (ISM), also referred to as the Warm Ionized Medium, is by now well established from deep imaging and spectroscopic surveys in several emission lines in external galaxies. Diffuse ionized gas is characterized by a relatively high ratio of [SII] over Hα intensities, typically twice as high as for discrete HII regions. The diffuse gas has been mapped in both edge-on and more face-on galaxies providing information on the radial and vertical distribitions. Emission from diffuse ionized gas is strongest around star forming regions. The vertical distribution appears related to the radio continuum thick-disk emission. We also briefly discuss ionization mechanisms, and the connection between star formation characteristics and morphology of the interstellar medium.

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