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Journal articles on the topic 'Interstellar and Intergalactic Matter'

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Published: 10 December 2022

Last updated: 29 January 2023

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1

Dyson, John, Thomas J. Millar, Bo Reipurth, You-Hua Chu, Gary J. Ferland, José Franco, Chon Trung Hua, et al. "DIVISION VI: INTERSTELLAR MATTER." Proceedings of the International Astronomical Union 3, T26B (December 2007): 173. http://dx.doi.org/10.1017/s1743921308023971.

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Division VI gathers astronomers studying the diffuse matter in space between stars, ranging from primordial intergalactic clouds, via dust and neutral and ionized gas in galaxies, to the densest molecular clouds and the processes by which stars are formed.

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Dyson, John, Tom Millar, You-Hua Chu, Gary Ferland, Pepe Franco, Trung Hua, Susana Lizano, et al. "Division VI: Interstellar Matter." Proceedings of the International Astronomical Union 1, T26A (December 2005): 267–71. http://dx.doi.org/10.1017/s1743921306004662.

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Commission 34 covers diffuse matter in space on scales ranging from the circumstellar to the galactic and intergalactic. As such it has enormous scope and because of this, it alone forms Division VI. Key aspects include star formation, matter around evolved stars, astrochemistry, nebulae, galactic and intergalactic clouds and the multitude of effects of the interaction of stars with their surroundings. Associated with these areas are a huge range of physical and chemical processes including hydrodynamics and magnetohydrodynamics, radiative processes, molecular physics and chemistry, plasma processes and others too numerous to name. These are complemented by an equally huge range of observational studies using practically all space and ground-based instrumentation at nearly all observable wavelengths. A glance at any data-base of publications over the past few years attests to the vigorous state of these studies. The current membership of the Division is around 800. It also has three separate working groups.

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3

Dopita, Michael A., Rafael Bachiller, Michael Burton, John Dyson, Debra Elmegreen, Thomas Henning, Sun Kwok, et al. "Division VI: Interstellar Matter: (Matière Interstellaire)." Transactions of the International Astronomical Union 24, no. 1 (2000): 277–80. http://dx.doi.org/10.1017/s0251107x00003175.

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Division VI of the International Astronomical Union deals with Interstellar Matter, and incorporates Commission 34. It gathers astronomers studying the diffuse matter in space between the stars, ranging from primordial intergalactic clouds via dust and neutral and ionised gas in galaxies to the densest molecular clouds and the processes by which stars are formed. There are approximately 730 members. The working groups in Planetary Nebulae and Cosmochemistry have served us well in organising periodic seminars in these subject areas. However, the Organising Committee has recognised that other developing areas of the ISM are not properly represented in the current organisation. In January 1997, the Division formed a new ISM working group on Star Forming Regions including cross-divisional representation to monitor progress in their fields and to help develop proposals for future IAU Symposia or Colloquia. In the future, especially in view of the rapid developments in spaceborne X-ray and IR astronomy, Division VI also hopes to form other working groups on the Hot ISM and the Extragalactic ISM.

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4

Roos, M., S. Bowyer, M. Lampton, and J. T. Peltoniemi. "Do Massive Neutrinos Ionize Intergalactic HI?" Symposium - International Astronomical Union 168 (1996): 563–67. http://dx.doi.org/10.1017/s0074180900110708.

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The radiative decay of massive relic 30eV neutrinos could explain several observational puzzles including the missing dark matter in the universe and the anomalous degree of ionization of interstellar matter in the Galaxy. We note that various non-standard particle physics models with extended scalar sector or minimal supersymmetry have sufficient freedom to accommodate such neutrinos. We discuss observational constraints in the immediate Solar neighborhood, in nearby regions of low interstellar absorption, in the Galactic halo, in clusters of galaxies, and in extragalactic space. Although some observations have been interpreted as ruling out this picture, we note that this is true only for models in which extreme concentrations of neutrinos occur in clusters of galaxies. An instrument is under development to measure the cosmic diffuse EUV background in the local Solar neighborhood, for flight on the Spanish Minisat satellite platform. This instrument will have the capability of providing a definitive test of the radiative neutrino decay hypothesis.

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5

Taniguchi, Yoshiaki. "IAU Symposium No. 217 Recycling of Intergalactic and Interstellar Matter." TRENDS IN THE SCIENCES 9, no. 5 (2004): 76. http://dx.doi.org/10.5363/tits.9.5_76.

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6

Pettini, M. "AAT Observations of the Interstellar Medium towards SN 1987A." Publications of the Astronomical Society of Australia 7, no. 4 (1988): 527–34. http://dx.doi.org/10.1017/s1323358000022736.

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AbstractThe exceptional brightness of SN 1987A has provided a unique opportunity to probe intervening gas clouds in the disk and halo of our Galaxy and in the Large Magellanic Cloud, as well as intergalactic matter between the two. At the AAO we have exploited this opportunity in two ways: in searches for very weak interstellar features requiring exceptionally high signal-to-noise ratio spectra, and in recording known interstellar lines with unprecedentedly high spectral resolution. We are also monitoring photographically the evolution of the light-echoes to map the three-dimensional distribution of interstellar matter near the supernova. Surprisingly high column densities of million-degree gas have been found in the LMC through the first detection of [Fe X] in absorption. The hot gas may fill the interior of a ‘superbubble’, created by the combined effects of previous supernovae in this active region of star-formation; this cavity may be related to the shells of interstellar matter giving rise to the light-echoes. The ultra-high resolution observations, which required the rapid construction of a dedicated new spectrograph, were successful in resolving the hyperfine structure of the sodium D lines in several interstellar clouds. This implies that the clouds are at temperatures of at most 170 K and have internal turbulent velocities of no more than 0.3 km s−1, even though some are moving with high velocities relative to the Sun.

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Cashman, Frances H., Varsha P. Kulkarni, Romas Kisielius, Gary J. Ferland, and Pavel Bogdanovich. "Atomic Data Revisions for Transitions Relevant to Observations of Interstellar, Circumgalactic, and Intergalactic Matter." Astrophysical Journal Supplement Series 230, no. 1 (May 19, 2017): 8. http://dx.doi.org/10.3847/1538-4365/aa6d84.

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8

Shull, J. Michael. "Atomic data needs for studies of the interstellar and intergalactic medium." Physica Scripta T47 (January 1, 1993): 165–70. http://dx.doi.org/10.1088/0031-8949/1993/t47/026.

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9

Komiya, Yutaka, Takuma Suda, Asao Habe, and Masayuki Fujimoto. "Galactic archeology with extremely metal-poor stars." Proceedings of the International Astronomical Union 4, S255 (June 2008): 330–35. http://dx.doi.org/10.1017/s1743921308025027.

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AbstractExtremely metal-poor (EMP) stars are thought to be formed in the low-mass protogalaxies as building blocks of the Milky Way and can be probes to investigate the early stage of galaxy formation and star formation in the early universe. We study the formation history of EMP stars in the Milky Way halo using a new model of chemical evolution based on the hierarchical theory of the galaxy formation. We construct the merging history of the Milky Way halo based on the extended Press-Schechter formalism, and follow the star formation and chemical evolution along the merger tree. The abundance trends and number of low-mass stars predicted in our model are compared with those of observed EMP stars. Additionally, in order to clarify the origin of hyper metal poor stars, we investigate the change of the surface metal abundances of stars by accretion of interstellar matter. We also investigate the pre-enrichment of intergalactic matter by the first supernovae.

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10

Pettini, Max. "Studies of the ISM in the LMC using SN1987A." Symposium - International Astronomical Union 148 (1991): 431. http://dx.doi.org/10.1017/s0074180900201071.

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The exceptional brightness of SN1987A provided a wealth of opportunities for probing not only the interstellar medium in our Galaxy and in the Large Magellanic Cloud (LMC), but also any intergalactic matter between the two. Spectroscopic work has been directed both towards searches for very weak absorption lines, which require data of exceptionally high signal-to-noise ratio, and towards recording spectra of known features at unprecedentedly high resolution. Both approaches have yielded exciting and unexpected results. The first detection of [FeX] absorption has revealed the presence of million-degree gas in the interstellar medium of the LMC, possibly resulting from the explosions of previous supernovae in the 30-Doradus HII region. The ultra-high-resolution observations have been successful in resolving the hyperfine structure of the sodium D lines in several interstellar clouds along the line of sight to the supernova. This implies that the clouds are at temperatures of, at most, 170 K and have internal turbulent velocities of not more than 0.2 km s−1; large-scale motions thus appear to be mainly subsonic in these clouds. Radio observations of HI emission at 21-cm with the Parkes telescope have been combined with measurements of a variety of ultraviolet absorption lines, obtained with the International Ultraviolet Explorer satellite, to give the most detailed picture yet of the chemical composition of the gas between the Galaxy and the LMC. Finally, photographic monitoring of the light echo of SN 1987A over the last two years has provided a three-dimensional view of the interstellar environment in which SN 1987A exploded, complementing vividly the information deduced from the spectroscopic results.

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11

Xu, J., and J. L. Han. "Evidence for Strong Intracluster Magnetic Fields in the Early Universe." Astrophysical Journal 926, no. 1 (February 1, 2022): 65. http://dx.doi.org/10.3847/1538-4357/ac4095.

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Abstract The origin of magnetic fields in clusters of galaxies is still a matter of debate. Observations for intracluster magnetic fields over a wide range of redshifts are crucial to constrain possible scenarios for the origin and evolution of the fields. Differences in Faraday rotation measures (RMs) of an embedded double radio source, i.e., a pair of lobes of mostly Fanaroff–Riley type II radio galaxies, are free from the Faraday rotation contributions from the interstellar medium inside the Milky Way and the intergalactic medium between radio galaxies and us, and hence provide a novel way to estimate average magnetic field within galaxy clusters. We have obtained a sample of 627 pairs whose RMs and redshifts are available in the most updated RM catalogs and redshift databases. The RM differences of the pairs are derived. The statistically large RM differences for pairs of redshifts z > 0.9 indicate that intracluster magnetic fields are as strong as about 4 μG. Such strong magnetic fields in the intracluster medium at the half age of the universe, comparable to the intracluster field strength in nearby galaxy clusters, pose a challenge to the theories of the origin of cosmic magnetic fields.

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12

White, Simon. "The influence of halo evolution on galaxy structure." Proceedings of the International Astronomical Union 10, H16 (August 2012): 371. http://dx.doi.org/10.1017/s1743921314011430.

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AbstractIf Einstein-Newton gravity holds on galactic and larger scales, then current observations demonstrate that the stars and interstellar gas of a typical bright galaxy account for only a few percent of its total nonlinear mass. Dark matter makes up the rest and cannot be faint stars or any other baryonic form because it was already present and decoupled from the radiation plasma at z = 1000, long before any nonlinear object formed. The weak gravito-sonic waves so precisely measured by CMB observations are detected again at z = 4 as order unity fluctuations in intergalactic matter. These subsequently collapse to form today's galaxy/halo systems, whose mean mass profiles can be accurately determined through gravitational lensing. High-resolution simulations link the observed dark matter structures seen at all these epochs, demonstrating that they are consistent and providing detailed predictions for all aspects of halo structure and growth. Requiring consistency with the abundance and clustering of real galaxies strongly constrains the galaxy-halo relation, both today and at high redshift. This results in detailed predictions for galaxy assembly histories and for the gravitational arena in which galaxies live. Dark halos are not expected to be passive or symmetric but to have a rich and continually evolving structure which will drive evolution in the central galaxy over its full life, exciting warps, spiral patterns and tidal arms, thickening disks, producing rings, bars and bulges. Their growth is closely related to the provision of new gas for galaxy building.

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13

Starling, R. L. C., A. Rowlinson, A. J. van der Horst, and R. A. M. J. Wijers. "LOFAR detectability of prompt low-frequency radio emission during gamma-ray burst X-ray flares." Monthly Notices of the Royal Astronomical Society 494, no. 4 (April 30, 2020): 5787–92. http://dx.doi.org/10.1093/mnras/staa1168.

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ABSTRACT The prompt emission in long gamma-ray bursts (GRBs) arises from within relativistic outflows created during the collapse of massive stars, and the mechanism by which radiation is produced may be either magnetically or matter dominated. In this work, we suggest an observational test of a magnetically dominated Poynting flux model that predicts both γ-ray and low-frequency radio pulses. A common feature among early light curves of long GRBs are X-ray flares, which have been shown to arise from sites internal to the jet. Ascribing these events to the prompt emission, we take an established Swift XRT flare sample and apply a magnetically dominated wind model to make predictions for the timing and flux density of corresponding radio pulses in the ∼100–200 MHz band observable with radio facilities such as LOFAR. We find that 44 per cent of the X-ray flares studied would have had detectable radio emission under this model, for typical sensitivities reached using LOFAR’s rapid response mode and assuming negligible absorption and scattering effects in the interstellar and intergalactic medium. We estimate the rate of Swift GRBs displaying X-ray flares with detectable radio pulses, accessible to LOFAR, of order seven per year. We determine that LOFAR triggered observations can play a key role in establishing the long debated mechanism responsible for GRB prompt emission.

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14

Hanasz, M., D. Woltanski, and K. Kowalik. "Interstellar and intergalactic dynamos." Proceedings of the International Astronomical Union 8, S294 (August 2012): 225–36. http://dx.doi.org/10.1017/s1743921313002573.

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AbstractWe review recent developments of amplification models of galactic and intergalactic magnetic field. The most popular scenarios involve variety of physical mechanisms, including turbulence generation on a wide range of physical scales, effects of supernovae, buoyancy as well as the magnetorotational instability. Other models rely on galaxy interaction, which generate galactic and intergalactic magnetic fields during galaxy mergers. We present also global galactic-scale numerical models of the Cosmic Ray (CR) driven dynamo, which was originally proposed by Parker (1992). We conduct a series of direct CR+MHD numerical simulations of the dynamics of the interstellar medium (ISM), composed of gas, magnetic fields and CR components. We take into account CRs accelerated in randomly distributed supernova (SN) remnants, and assume that SNe deposit small-scale, randomly oriented, dipolar magnetic fields into the ISM. The amplification timescale of the large-scale magnetic field resulting from the CR-driven dynamo is comparable to the galactic rotation period. The process efficiently converts small-scale magnetic fields of SN-remnants into galactic-scale magnetic fields. The resulting magnetic field structure resembles the X-shaped magnetic fields observed in edge-on galaxies.

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15

Escobar, G. J., L. J. Pellizza, and G. E. Romero. "Cosmic-ray production from neutron escape in microquasar jets." Astronomy & Astrophysics 650 (June 2021): A136. http://dx.doi.org/10.1051/0004-6361/202039860.

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Context. The origin of Galactic cosmic rays remains a matter of debate, but supernova remnants are commonly considered to be the main place where high-energy cosmic rays are accelerated. Nevertheless, current models predict cosmic-ray spectra that do not match observations and the efficiency of the acceleration mechanism is still undetermined. On the other hand, the contribution of other kinds of sources to the Galactic cosmic-ray population is still unclear, and merits investigation. Aims. In this work we explore a novel mechanism through which microquasars might produce cosmic rays. In this scenario, microquasar jets generate relativistic neutrons, which escape and decay outside the system; protons and electrons, created when these neutrons decay, escape to the interstellar medium as cosmic rays. Methods. We introduce the relativistic neutron component through a coupling term in the transport equation that governs the jet proton population. We compute the escape rate and decay distribution of these neutrons, and follow the propagation of the decay products until they escape the system and become cosmic rays. We then compute the spectra of these cosmic rays. Results. Neutrons can drain only a small fraction of the jet power as cosmic rays. The most promising scenarios arise in extremely luminous systems (Ljet ∼ 1040 erg s−1), in which the fraction of jet power deposited in cosmic rays can reach ∼0.001. Slow jets (Γ ≲ 2, where Γ is the bulk Lorentz factor) favour neutron production. The resulting cosmic-ray spectrum is similar for protons and electrons, which share the power in the ratio given by neutron decay. The spectrum peaks at roughly half the minimum energy of the relativistic protons in the jet; it is soft (spectral index ∼3) above this energy, and almost flat below. Conclusions. The proposed mechanism produces more energetic cosmic rays from microquasars than those presented by previous works in which the particles escape through the jet terminal shock. Values of spectral index steeper than 2 are possible for cosmic rays in our model and these indeed agree with those required to explain the spectral signatures of Galactic cosmic rays, although only the most extreme microquasars provide power comparable to that of a typical supernova remnant. The mechanism explored in this work may provide stronger and softer cosmic-ray sources in the early Universe, and therefore contribute to the heating and reionisation of the intergalactic medium.

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16

Han, J. L. "Observing Interstellar and Intergalactic Magnetic Fields." Annual Review of Astronomy and Astrophysics 55, no. 1 (August 18, 2017): 111–57. http://dx.doi.org/10.1146/annurev-astro-091916-055221.

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17

Ott, Jürgen. "Dwarf Galaxies: The Interstellar‐Intergalactic Medium Connection." Publications of the Astronomical Society of the Pacific 115, no. 803 (January 2003): 141. http://dx.doi.org/10.1086/345106.

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18

Wiita, Paul J., and Alexander Rosen. "Interactions of Jets with Interstellar and Intergalactic Media." Symposium - International Astronomical Union 134 (1989): 467–68. http://dx.doi.org/10.1017/s0074180900141671.

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Jets emanating from AGN propagate first through an isothermal, but roughly power-law in density, galactic halo and then into a hotter, less dense, and uniform intergalactic medium (IGM) or intracluster medium (ICM). We use a three-dimensional boundary-following code (Mitteldorf & Wiita 1988), altered to allow for a two-phase external medium. We vary the beam power, P, the redshift, z, the radius of the galactic halo/IGM interface, Rh, the steepness of the power-law fall-off within the halo, n, and the temperature ratio of the IGM (or ICM) to the halo, Tr to estimate the average linear sizes of extragalactic radio galaxies (RGs). Good agreement is obtained with regard to the relationships between the overall linear size of such radio sources and both the total radio power (at fixed redshift) and the cosmological redshift (at fixed power). These numerical models tend to support recent analytical models (Gopal–Krishna & Wiita [GW] 1987, 1988).

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19

Weber, J. A., A. W. A. Pauldrach, and T. L. Hoffmann. "Numerical models for the diffuse ionized gas in galaxies." Astronomy & Astrophysics 622 (February 2019): A115. http://dx.doi.org/10.1051/0004-6361/201832649.

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Context. The diffuse ionized gas (DIG) constitutes the largest fraction of the total ionized interstellar matter in star-forming galaxies, but it is still unclear whether the ionization is driven predominantly by the ionizing radiation of hot massive stars, as in H II regions, or whether additional sources of ionization have to be considered. Key to understanding the ionization mechanisms in the DIG is the line emission by the ionized gas. Aims. We systematically explore a plausible subset of the parameter space involving effective temperatures and metallicities of the ionizing sources, the effects of the hardening of their radiation by surrounding “leaky” H II regions with different escape fractions, as well as different scenarios for the clumpiness of the DIG, and compute the resulting line strength ratios for a number of diagnostic optical emission lines. Methods. For the ionizing fluxes we computed a grid of stellar spectral energy distributions (SEDs) from detailed, fully non-LTE model atmospheres that include the effects of stellar winds and line blocking and blanketing. To calculate the ionization and temperature structure in the interstellar gas we used spherically symmetric photoionization models and state-of-the-art three-dimensional (3D) non-LTE radiative transfer simulations, considering hydrogen, helium, and the most abundant metals. We first applied these methods to classical H II regions around hot stars, using the model SEDs at different metallicities and effective temperatures as ionizing fluxes, and compute the SEDs of the escaping radiation for different escape fractions of hydrogen-ionizing photons. In a second step, we studied the effects of the escaping radiation on the more dilute and extended DIG. Using 3D models simulating a section of a galactic spiral arm, we computed the ionization structure in the DIG for different scenarios for the inhomogeneity of the gas, assuming ionization by a stellar population SED based on plausible parameters. Results. We provide quantitative predictions of how the line ratios from H II regions and the DIG vary as a function of metallicity Z, stellar effective temperature Teff, and escape fraction fesc from the H II region. The range of predicted line ratios reinforces the hypothesis that the DIG is ionized by (filtered) radiation from hot stars. At one-tenth solar metallicity, radiation hardening is mostly due to hydrogen and helium, whereas at solar metallicity absorption by metals plays a significant role. The effects of hardening are seen primarily in the increase in the emission line ratios of the most important cooling lines of the gas, [N II]∕Hβ and [O II]∕Hβ at lower Teff, and [O III]∕Hβ at higher Teff. For low Teff nearly the entire He I-ionizing radiation is absorbed in the H II regions, thereby preventing the formation of high ionization stages such as O III in the DIG. The ionization structure of the DIG depends strongly on both the clumping factor fcl = 〈nH2〉/〈nH2〉 and the large-scale distribution of the gas. In our simulations about 10% of the ionizing radiation produced by hot massive stars in a spiral arm is sufficient to ionize the DIG up to a height of approximately 1 kpc above the galactic plane for a clumping factor close to the observed value of fcl ~ 5. Even small changes in simulation parameters such as the clumping factor can lead to considerable variation in the ionized volume. Both for a more homogeneous gas and a very inhomogeneous gas containing both dense clumps and channels with low gas density, the ionized region in the dilute gas above the galactic plane can cease to be radiation-bounded, allowing the ionizing radiation to leak into the intergalactic medium. Comparison of observed and predicted line ratios indicates that the DIG is typically ionized with a softer SED than predicted by the chosen stellar population synthesis model.

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20

Kovačević, Andjelka B. "On Mautner-Type Probability of Capture of Intergalactic Meteor Particles by Habitable Exoplanets." Sci 1, no. 2 (July 15, 2019): 40. http://dx.doi.org/10.3390/sci1020040.

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Both macro and microprojectiles (e.g., interplanetary, interstellar and even intergalactic material) are seen as an important vehicle for the exchange of (bio)material within our solar system as well as between stellar systems in our Galaxy. Accordingly, this requires estimates of the impact probabilities for different source populations of projectiles, specifically for intergalactic meteor particles which have received relatively little attention since considered as rare events (discrete occurrences that are statistically improbable due to their very infrequent appearance). We employ the simple but yet comprehensive model of intergalactic microprojectile capture by the gravity of exoplanets which enables us to estimate the map of collisional probabilities for an available sample of exoplanets in habitable zones around host stars. The model includes a dynamical description of the caption adopted from Mautner model of interstellar exchange of microparticles and changed for our purposes. We use statistical and information metrics to calculate probability map of intergalactic meteorite particle capture. Moreover, by calculating the entropy index map we measure the concentration of these rare events. By adopting a model from immigration theory, we show that the transient distribution of birth/death/immigration of material for the simplest case has a high value.

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21

R. Sembach, Kenneth. "Spectroscopic Observations of Baryons in the Local Universe." Symposium - International Astronomical Union 216 (2005): 274–89. http://dx.doi.org/10.1017/s0074180900196718.

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There is increasing observational evidence that hot, highly-ionized interstellar and intergalactic gas plays a significant role in the evolution of galaxies in the local universe. Recent observations from several ultraviolet and X-ray observatories have been used to study the highly ionized high velocity cloud system in the vicinity of the Galaxy, the hot gaseous corona of the Galaxy, and highly ionized absorption-line systems at low redshift. The primary spectral diagnostics of this warm-hot interstellar/intergalactic medium are ultraviolet and X-ray absorption lines of O vi and O vii. The observational data fit well into the framework of current theories for the evolution of large-scale structure in the universe, which predict that a significant fraction of the baryonic material at low redshift is contained in highly ionized intergalactic gas. In this paper, I summarize some of the recent highlights of spectroscopic observations of the hot baryons in the local universe.

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22

Kwan, Juliana, Geraint F. Lewis, and J. Berian James. "The Adventures of the Rocketeer: Accelerated Motion Under the Influence of Expanding Space." Publications of the Astronomical Society of Australia 27, no. 1 (2010): 15–22. http://dx.doi.org/10.1071/as09050.

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AbstractIt is well known that interstellar travel is bounded by the finite speed of light, but on very large scales any rocketeer would also need to consider the influence of cosmological expansion on their journey. This paper examines accelerated journeys within the framework of Friedmann–Lemaître–Robertson–Walker universes, illustrating how the duration of a fixed acceleration sharply divides exploration over interstellar and intergalactic distances. Furthermore, we show how the universal expansion increases the difficulty of intergalactic navigation, with small uncertainties in cosmological parameters resulting in significantly large deviations. This paper also shows that, contrary to simplistic ideas, the motion of any rocketeer is indistinguishable from Newtonian gravity if the acceleration is kept small.

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23

Fabian, A. C., and X. Barcons. "Intergalactic matter." Reports on Progress in Physics 54, no. 8 (August 1, 1991): 1069–122. http://dx.doi.org/10.1088/0034-4885/54/8/002.

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24

Goldhaber, Maurice, and Virginia Trimble. "Limits on the chirality of interstellar and intergalactic space." Journal of Astrophysics and Astronomy 17, no. 1-2 (June 1996): 17–21. http://dx.doi.org/10.1007/bf02709342.

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25

Shull, J. Michael. "Theoretical Problems in the Interstellar Medium." Highlights of Astronomy 9 (1992): 109–14. http://dx.doi.org/10.1017/s1539299600008807.

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AbstractI review recent theoretical developments in the structure, heating, and ionization of the interstellar medium. Among the unsolved issues are: the vertical support of the gas layer; the ionization source for the H+ layer and diffuse line emission above the Galactic plane; the physics of stochastic heating of small dust grains and the resulting infrared spectra. Turbulent mixing may play an important role in the intercloud medium and diffuse emission above the disk. I conclude with some possible analogies between the intergalactic medium and the interstellar medium.

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26

Antonuccio-Delogu, V., and J. Silk. "AGN feedback from jet-ISM/IGM interactions." Proceedings of the International Astronomical Union 3, S245 (July 2007): 31–32. http://dx.doi.org/10.1017/s1743921308017201.

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AbstractWe study the propagation of relativistic jets originating from AGNs within the Interstellar/Intergalactic Medium of their host galaxies, and use it to build a model for the inihibition of stellar formation within the expanding cocoon.

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27

Ikhsanov, Nazar R., Galina L. Klimchitskaya, and Vladimir M. Mostepanenko. "Editorial to the Special Issue “Advances in the Physics of Stars—In Memory of Prof. Yuri N. Gnedin”." Universe 8, no. 4 (April 13, 2022): 239. http://dx.doi.org/10.3390/universe8040239.

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This Special Issue collects articles devoted to various aspects of astrophysics which can be understood as a science investigating stars, galaxies, their types and properties, stages of their evolution, distribution in the Universe and the interstellar and intergalactic media [...]

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28

Kovačević, Andjelka B. "On Mautner-Type Probability of Capture of Intergalactic Meteor Particles by Habitable Exoplanets." Sci 1, no. 3 (October 19, 2019): 61. http://dx.doi.org/10.3390/sci1030061.

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Both macro and microprojectiles (e.g., interplanetary, interstellar and even intergalactic material) are seen as important vehicles for the exchange of potential (bio)material within our solar system as well as between stellar systems in our Galaxy. Accordingly, this requires estimates of the impact probabilities for different source populations of projectiles, including for intergalactic meteor particles which have received relatively little attention since considered as rare events (discrete occurrences that are statistically improbable due to their very infrequent appearance). We employ the simple but comprehensive model of intergalactic microprojectile capture by the gravity of exoplanets which enables us to estimate the map of collisional probabilities for an available sample of exoplanets in habitable zones around host stars. The model includes a dynamical description of the capture adopted from Mautner model of interstellar exchange of microparticles and changed for our purposes. We use statistical and information metrics to calculate probability map of intergalactic meteorite particle capture. Moreover, by calculating the entropy index map we estimate the concentration of these rare events. We further adopted a model from immigration theory, to show that the time dependent distribution of single molecule immigration of material indicates high survivability of the immigrated material taking into account birth and death processes on our planet. At present immigration of material can not be observationally constrained but it seems reasonable to think that it will be possible in the near future, and to use it along other proposed parameters for life sustainability on some planet.

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29

Okuda, H. "Observations of Diffuse IR Background Radiation by IRTS and IRIS." Symposium - International Astronomical Union 168 (1996): 117–24. http://dx.doi.org/10.1017/s0074180900110009.

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Diffuse background radiation is integrated light which is consisted of various components of interplanetary, stellar, interstellar, galactic and intergalactic origins as well as cosmic background radiation, the remnant of the pre-galactic phenomena in the early history of the universe.

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Peterson, Bruce A. "QSO Absorption Lines: Heavy Elements and Lyman-α Clouds." Symposium - International Astronomical Union 119 (1986): 555–61. http://dx.doi.org/10.1017/s0074180900153458.

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The absorption lines in QSO spectra may be produced in material surrounding the QSO, in intergalactic clouds and in the interstellar gas of galaxies along the line of sight to the QSO. The intergalactic clouds produce weak Lyα absorption lines. The intervening galaxies produce absorption line systems with heavy element abundances and ionizations similar to the H i clouds in the halo of our galaxy. The material surrounding the QSO produces broad absorption troughs. Evidence suggests a continuity in spatial correlation and heavy element abundances for the Lyα clouds and intervening galaxies.

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Bowen, David V., Katherine C. Roth, J. Chris Blades, and David M. Meyer. "Interstellar and intergalactic magnesium and sodium absorption toward SN 1993J." Astrophysical Journal 420 (January 1994): L71. http://dx.doi.org/10.1086/187165.

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32

Uchida, Yutaka. "Magnetodynamical jets and flows in the interstellar and intergalactic space." Advances in Space Research 10, no. 9 (January 1990): 31–38. http://dx.doi.org/10.1016/0273-1177(90)90205-e.

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Petitjean, P. "The high redshift intergalactic and interstellar media with X-shooter." Astronomische Nachrichten 332, no. 3 (March 2011): 309–14. http://dx.doi.org/10.1002/asna.201111544.

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Lazio, T. Joseph W., Roopesh Ojha, Alan L. Fey, Lucyna Kedziora‐Chudczer, James M. Cordes, David L. Jauncey, and James E. J. Lovell. "Angular Broadening of Intraday Variable AGNs. II. Interstellar and Intergalactic Scattering." Astrophysical Journal 672, no. 1 (January 2008): 115–21. http://dx.doi.org/10.1086/520572.

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35

Kovacevic, Andjelka. "On Mautner-Type Probability of Capture of Intergalactic Meteor Particles by Habitable Exoplanets." Sci 1, no. 2 (August 9, 2019): 47. http://dx.doi.org/10.3390/sci1020047.

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Both macro and microprojectiles (e.g., interplanetary, interstellar and even intergalactic material)are seen as important vehicles for the exchange of potential (bio)material within our solar system as wellas between stellar systems in our Galaxy. Accordingly, this requires estimates of the impact probabilitiesfor different source populations of projectiles, including for intergalactic meteor particles which havereceived relatively little attention since considered as rare events (discrete occurrences that are statisticallyimprobable due to their very infrequent appearance). We employ the simple but yet comprehensivemodel of intergalactic microprojectile capture by the gravity of exoplanets which enables us to estimatethe map of collisional probabilities for an available sample of exoplanets in habitable zones around hoststars. The model includes a dynamical description of the capture adopted from Mautner model ofinterstellar exchange of microparticles and changed for our purposes. We use statistical and informationmetrics to calculate probability map of intergalactic meteorite particle capture. Moreover, by calculatingthe entropy index map we measure the concentration of these rare events. We further adopted a modelfrom immigration theory, to show that the transient distribution of birth/death/immigration of materialfor the simplest case has a high value.

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Jakobsen, Peter. "The Far-Ultraviolet Background." Symposium - International Astronomical Union 168 (1996): 229–36. http://dx.doi.org/10.1017/s0074180900110113.

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Extensive reviews of the diffuse background at ultraviolet (λ1000 – 2500 å) wavelengths have been given by Davidsen, Bowyer & Lampton (1974), Paresce & Jakobsen (1980), and most recently by Bowyer (1992) and Henry (1992). Since many astronomical sources emit radiation with photon energies in the rangehv≃ 10 – 20 eV through various thermal and non-thermal emission processes, the diffuse UV background is of relevance for a range of topics. These include the study of the properties of interplanetary and interstellar dust grains, thermal line emission from the interstellar and intergalactic gas, the integrated light of galaxies, and radiative decay of exotic cosmological particles.

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Shchekinov, Yuri A., Vladimir N. Lukash, Elena V. Mikheeva, and Sergei V. Pilipenko. "Interstellar and intergalactic gas in the far IR and submillimeter spectral ranges." Uspekhi Fizicheskih Nauk 187, no. 10 (February 2017): 1033–70. http://dx.doi.org/10.3367/ufnr.2017.02.038059.

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Sembach, Kenneth R., J. Christopher Howk, Blair D. Savage, J. Michael Shull, and William R. Oegerle. "Far‐Ultraviolet Spectroscopy of the Intergalactic and Interstellar Absorption toward 3C 273." Astrophysical Journal 561, no. 2 (November 10, 2001): 573–99. http://dx.doi.org/10.1086/323408.

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Shchekinov, Yu A., V. N. Lukash, E. V. Mikheeva, and S. V. Pilipenko. "Interstellar and intergalactic gas in the far IR and submillimeter spectral ranges." Physics-Uspekhi 60, no. 10 (October 31, 2017): 961–93. http://dx.doi.org/10.3367/ufne.2017.02.038059.

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Gnedin, Yu N., and M. Yu Piotrovich. "New results in searching for axions by astronomical methods." International Journal of Modern Physics A 31, no. 02n03 (January 20, 2016): 1641019. http://dx.doi.org/10.1142/s0217751x16410190.

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We discuss the astronomical methods of searching for light Goldstone bosons (axions and arions). The basic idea is to use processes of coupling between axions and photons: a) the axion decay into two photons; b) the transformation process of photons into axions (arions) in the magnetic fields of stars and also of interstellar and intergalactic media; c) the inverse process of transformations of axions (arions) which are generated into cores of stars into X-ray photons. The decaying axions affect upon the diffuse extragalactic background radiation, the brightness of the night sky and especially on the intergalactic light of clusters of galaxies due to generation of the axion radiative decay emission line. The processes (b) and (c) are strongly dependent on polarization state of photon and may produce a noticeable amount of linear polarization.

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Yan, Huirong, and A. Lazarian. "Atomic alignment: New Diagnostics of Magnetic Field in Diffuse Medium." Proceedings of the International Astronomical Union 5, H15 (November 2009): 446–47. http://dx.doi.org/10.1017/s1743921310010215.

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AbstractWe discuss a new technique of studying magnetic fields in diffuse astrophysical media, e.g. interstellar and intergalactic gas/plasma. This technique is based on the angular momentum alignment of atoms and ions in their ground or metastable states. The alignment reveals itself in terms of the polarization of the absorbed and emitted light. The corresponding studies of magnetic fields can be performed with multiband spectropolarimetry, from UV, optical, to IR/radio. A unique feature of these studies is that they can reveal the 3D orientation of magnetic field. We mention several cases of interplanetary, circumstellar and interstellar magnetic fields for which the studies of magnetic fields using ground state atomic alignment effect are promising.

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Siejkowski, Hubert, Marian Soida, Katarzyna Otmianowska-Mazur, Michał Hanasz, and Dominik Bomans. "Cosmic-ray driven dynamo in the medium of irregular galaxy." Proceedings of the International Astronomical Union 4, S259 (November 2008): 557–58. http://dx.doi.org/10.1017/s1743921309031317.

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AbstractWe investigate the cosmic ray driven dynamo in the interstellar medium of irregular galaxy. The observations (Chyży et al. 2000, 2003) show that the magnetic field in irregular galaxies is present and its value reaches the same level as in spiral galaxies. However the conditions in the medium of irregular galaxy are very unfavorable for amplification the magnetic field due to slow rotation and low shearing rate.In this work we present numerical model of the interstellar medium in irregular galaxies. The model includes magnetohydrodynamical dynamo driven by cosmic rays in the interstellar medium provided by random supernova explosions. We describe models characterized by different shear and rotation. We find that even slow galactic rotation with low shearing rate gives amplification of the magnetic field. Simulations have shown that high amount of the magnetic energy flow out off the simulation region becoming an efficient source of intergalactic magnetic fields.

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Levshakov, Sergei A. "The Deuterium Abundance in QSO Absorption Systems: A Mesoturbulent Approach." Symposium - International Astronomical Union 198 (2000): 135–40. http://dx.doi.org/10.1017/s0074180900166513.

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A new method, based on simulated annealing technique and aimed at the inverse problem in the analysis of intergalactic or interstellar complex spectra of hydrogen and metal lines, is outlined. We consider the process of line formation in clumpy stochastic media accounting for fluctuating velocity and density fields self-consistently. Two examples of the analysis of ‘H+D’-like absorptions seen at za = 3.514 and 3.378 towards APM 08279+5255 are presented.

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Wszolek, Bogdan. "Observational limits on intergalactic matter." Astrophysics and Space Science 227, no. 1-2 (May 1995): 151–55. http://dx.doi.org/10.1007/bf00678075.

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Dopita, Michael A. "Stellar Feedback Through Cosmic Time: Starbursts & Superwinds." Proceedings of the International Astronomical Union 3, S250 (December 2007): 367–78. http://dx.doi.org/10.1017/s1743921308020711.

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AbstractThroughout cosmic time, the feedback of massive star winds and supernova explosions has been instrumental in determining the phase structure of the interstellar medium, controlling important aspects of both the formation and evolution of galaxies, producing galactic winds and enriching the intergalactic medium with heavy elements. In this paper, I review progress made in our theoretical understanding of how these feedback processes have operated throughout cosmic time from the epoch of the first stars through to the present day.

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Sunyaev, R. A., and D. O. Docenko. "Hydrogen-like nitrogen radio line from hot interstellar and warm-hot intergalactic gas." Astronomy Letters 33, no. 2 (February 2007): 67–79. http://dx.doi.org/10.1134/s1063773707020016.

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Beckman, J. E., M. Rozas, and J. H. Knapen. "Density Bounding of Giant HII Regions and the Ionisation of the Diffuse Interstellar Medium." Publications of the Astronomical Society of Australia 15, no. 1 (1998): 83–85. http://dx.doi.org/10.1071/as98083.

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AbstractThree different types of evidence are presented in favour of the hypothesis that the HII regions in disk galaxies with Hα luminosities greater than a critical value of 1038·6 erg s−1 are density-bounded, and that the escaping Lyman continuum photons from these are the principal ionising agents for the diffuse ISM in disk galaxies. This has important implications for the ionisation of the intergalactic medium, and for computed star formation rates in spirals.

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Cordes, J. M. "Galactic structure and turbulence, pulsar distances, and the intergalactic medium." Proceedings of the International Astronomical Union 8, S291 (August 2012): 211–16. http://dx.doi.org/10.1017/s1743921312023691.

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AbstractThis paper summarizes how multi-wavelength measurements will be aggregated to determine Galactic structure in the interstellar medium (ISM) and produce the next-generation electron density model. Fluctuations in density and magnetic field from parsec scales down to about 1000 km cause a number of propagation effects in both radio waves and cosmic rays. Density microstructure appears to include Kolmogorov-like turbulence. The next generation electron-density model, NE2012, will include about double the number of lines of sight with dispersion and scattering measurements and it will be anchored with a much larger number of pulsar parallax distances. The foreground Galactic model is crucial for inferring similar ionized structures in the intergalactic medium (IGM) from scattering measurements on high-z objects. Intergalactic scattering is discussed with reference to distant sources of radio bursts. In particular, the cosmological radio scattering horizon is defined along with its analog for the ISM.

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Reber, Grote. "Intergalactic Plasma." IEEE Transactions on Plasma Science 14, no. 6 (1986): 678–82. http://dx.doi.org/10.1109/tps.1986.4316618.

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Bochkarev, Nikolai G. "Local interstellar matter and interstellar bubbles." Astronomical & Astrophysical Transactions 3, no. 1 (November 1992): 3–16. http://dx.doi.org/10.1080/10556799208230534.

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