CHIPS Will Dip Into The Interstellar Medium CHIPS will Dip into the interstellar medium NASA's Cosmic Hot InterstellarPlasma Spectrometer (CHIPS) satellite will study space gases and dust. http://www.astronomy.com/Content/Dynamic/Articles/000/000/001/168gslky.asp
Extractions: Despite what many of us were told, space is not a complete vacuum. There exists a thin interstellar medium composed of dust and gas, which holds the very beginning of stars. As extremely hot gas cools and breaks down, concentrations develop that become the seeds of these brilliant bodies. Yet the mystery of how the mixture of dust and gases transforms into stars remains. NASA scientists hope a new space probe will provide insight on the evolution of these building blocks of stars and planets.
Extractions: Main Page Recent changes Edit this page Older versions Special pages Set my user preferences My watchlist Recently updated pages Upload image files Image list Registered users Site statistics Random article Orphaned articles Orphaned images Popular articles Most wanted articles Short articles Long articles Newly created articles All pages by title Blocked IP addresses Maintenance page External book sources Printable version Talk
Old Remnants And The Interstellar Medium next up previous Next Old Remnants and Bubbles Up Ergs The Evolution PreviousSurveys Systematics. Old Remnants and the interstellar medium. http://www.msi.umn.edu/Projects/twj/snrmeet/node15.html
Extractions: Next: Old Remnants and Bubbles Up: Ergs: The Evolution Previous: As SNRs disperse into the interstellar medium, they may be hard to recognize as individual objects, especially in our own galaxy. At the same time, galaxies contain many supershells caused by multiple supernovae and stellar winds. They are thought to dominate the morphology and often form chimneys that connect to the halo, providing a direct connection for gas and relativistic particles. They profoundly affect the ionization of the ISM, with their porosity allowing something like half of the ionizing photons from a star cluster to escape the immediate vicinity and travel long distances to provide a pervasive Warm Ionized Medium. These were some of the issues placed on the table by McCray and by Heiles in their reviews of old SNRs and the ISM. also discussed how ancient SNRs in the galactic halo could be responsible for the hot (UV and X-ray emitting) gas. SNRs also push the gas and magnetic field around, forming huge cavities with material and magnetic field lines pushed to the outside walls. The displaced matter exhibits itself in atomic, ionic, and molecular lines, which can be observed even in external galaxies.
Extractions: EXAMS AND GRADING: There will be homework, three exams and one comprehensive final. Class discussion and questions are appreciated and will be rewarded with credit. The homework is important in providing a basis for understanding the tests. The course grade will be determined according to the following plan: Websites of Interest: This Class
INTERSTELLAR MEDIUM AND STELLAR PHYSICS SOLAR SYSTEM. interstellar medium AND STELLAR PHYSICS. Contributors V. Calamai INTERSTELLARMEDIUM AND STAR FORMATION. The study of the interstellar http://www.arcetri.astro.it/pubblicazioni/GenReport/Rapp1996/node4.html
Extractions: Next: EXTRAGALACTIC AND HIGH ENERGY Up: Title Page Previous: SUN AND SOLAR SYSTEM Contributors: V. Calamai, P. Caselli, R. Cesaroni, A. Falchi, M. Felli, D. Galli, C. Giovanardi, M. Landolfi, A. Natta, E. Oliva, F. Palla, S. Randich, A. Richichi, G. Torricelli-Ciamponi, R. Valdettaro, M. Walmsley The study of the interstellar medium, with particular reference to the problems of chemistry, star formation and early stellar evolution, is one of the main fields of interest of the Arcetri community. In the following subsections, a brief outline is presented of the main observational and theoretical projects and results obtained during the last year. The IV Arcetri-Saclay-Grenoble meeting on Star Formation has taken place this year in Gif-sur-Yvette (Saclay, France) on September 9-10 and has been attended by a large number of researchers of this group. [ The work on the abundance of the light elements, in particular D and He, has been developed on both the theoretical and observational side. Current models of stellar evolution predict a production of
Extractions: While most of our work has had the goal of understanding the structure and evolution of white dwarfs, EUV observations of these stars can also tell us much about the intervening interstellar material. Although the original nebula from which the Solar System formed, about 4500 million years ago, will have been largely dissipated by the intense radiation from the young Sun and also left behind by the motion of the Solar System through interstellar space, more recent encounters with interstellar material may have affected us directly and at the very least influenced our astronomical observations. A Hammer-Aitoff plot in galactic coordinates, showing the distribution of white dwarf positions. The sizes of the symbols correspond to the HI column density along the line of sight. Squares = observations where a 228 Angstrom edge is not detected; triangles = 228 Angstrom edge detections analysed with H+He models; circles = 228 Angstrom edge detections analysed with heavy element models. The contours included indicate the distance (in pc) to the edge of the local cavity, as determined by Warwick et al. (MNRAS, Ionized material can be detected by the "shadowing" effect it has on the EUV spectra of other objects. Since, white dwarfs have strong EUV continua, they are ideal targets with which to search for interstellar absorption from HeI and HeII.
Benjamin J. McCall Observation of H 3 + in the Diffuse InterstellarMedium. 6/18/98. Click here to start. http://dib.berkeley.edu/~bjmccall/talks/osu98space/
The Local Interstellar Medium The Local interstellar medium. We turn now from a consideration of themost global aspect of the ISM to a consideration of its properties http://praxis.pha.jhu.edu/papers/papers/afdscirev_b/node7.html
Extractions: Next: Origin of Ultraviolet Up: Scientific Results Previous: The Galactic Corona about K and number density around . This gas is highly ionized and therefore provides no opacity for observations within 100 pc or so. Numerous investigations have shown, however, that there is a minimum column density of neutral atomic hydrogen of about toward all stars observed, and this minimum is all that is seen for stars in the local bubble. Thus, it appears that the Sun must be surrounded by a small, at least partially neutral cloud with approximately this column density. An atomic-hydrogen density of about 0.1 cm and a bubble size of 3-5 pc are consistent with the existing data. There is completely independent evidence of partially neutral interstellar gas in the immediate vicinity of the Sun from observations of solar Lyman- in the gas flowing through the solar system and a neutral-hydrogen density about five times as large with a temperature of about 8,000 K. The low observed ratio of H to He compared with the nominal cosmic abundance ratio of 10 has usually been interpreted to indicate that the hydrogen is significantly ionized, whereas the helium is largely neutral. However, known sources of ionizing radiation in the solar neighborhood are insufficient to maintain such a high degree of hydrogen ionization in the local cloud. ). We found a hydrogen column density of
Lecture 11: Interstellar Medium interstellar medium. (1) The interstellar medium (that's just a fancy namefor the matter between stars) consists of lowdensity gas and dust. http://www-astronomy.mps.ohio-state.edu/~ryden/ast162_3/notes11.html
Extractions: - Robert Frost The fact that we can look out far into the galaxy means that there must be very little matter between stars otherwise it would absorb all the starlight. Nevertheless, interstellar space is not entirely empty. 99% of the interstellar medium consists of very low density gas. How low in density is it? Let me tell you. The air we breathe has a density of approximately 10 molecules per cubic centimeter. (One cubic centimeter = 1 milliliter = 1/1000 liter). By contrast, the lowest density regions of interstellar space contains approximately 0.1 atoms per cubic centimeter.
IIA > Research Areas > Interstellar Medium Home Research Areas interstellar medium RESEARCH PROPOSALS. PHOTONICS LAB.COMPUTER FACILITIES. RESEARCH GRANTS. interstellar medium. Cometary Globules. http://www.iiap.ernet.in/research/interstellar.html
CITA Research 2001: Interstellar Medium CITA Research September 2000 August 2001 interstellar medium. Studiesof the interstellar medium (ISM) address the diffuse gas http://www.cita.utoronto.ca/~fiege/AnnRep/ResearchPages/ism.html
Extractions: Interstellar Medium Fiege , Matthews (McMaster) and Wilson (McMaster) have re-analyzed 850 micron SCUBA polarization data of OMC-3 region of the Orion A molecular cloud using improved software that was not available in 1998, when the data were taken. This region contains a bright filament that is partially fragmented into cores. Strong depolarization was observed toward the cores and along the spine of the filament. The polarization structure was modelled in detail using the technique outlined by Fiege and Pudritz (Ap.J, 2000, 544, 830), using their helical field model ( Fiege Fiege , Matthews and Moriarty-Schieven (JCMT) have used SCUBA polarimetry to map 3 star-forming systems of cores in Orion B. All 3 regions were found to contain polarization patterns that were indicative of highly ordered but non-uniform magnetic fields. Depolarization was found toward the bright cores in all 3 regions. NGC 2024 was the brightest and most interesting region mapped. 2 different models were proposed to account for the polarization data, and artificial polarization maps were computed for each model. Good agreement was found for a Fiege Using an 850 micron SCUBA map of the dark globule CB068 which contains a Class Young Stellar Object (YSO) and an associated bipolar outflow Fiege , Vallee (Herzberg) and Greaves (JCMT) have constructed a polarization model based on the Fiege The formation and collapse of a protostar involves the simultaneous infall and outflow of material in the presence of magnetic fields, self-gravity and rotation.
Extractions: Probing the High Redshift Intergalactic and Interstellar Medium with Gravitational Lenses The angular magnification in principle becomes arbitrarily high (there are some practical limits related to the finite size of the QSO emission region) as one approaches the QSO redshift. In practice it has been possible to study QSO absorption systems at transverse line of sight separations of a few tens of parsecs at redshifts 3-4. The angular magnification here would amount to several hundred (for example, we may see common absorption in two lensed images that appear 2 arseconds apart, while the proper separation of the lines of sight to the naked eye (i.e., unaided by the lensing effect) may be only a few milliarcseconds and would be impossible to resolve from the ground. The following figure shows two spectra (red and turqoise) in adjacent lines of sight to a lensed QSO, UM673. The absorption is caused by the CIV (1548, 1551) doublet at redshift 1.94. The pattern to the left of the origin of the x-axis comes from the 1458 A transition. It repeats itself to the right of the origin in the 1551 A line (though with lower optical depth because of the lower oscillator strength). The transverse separation between the lines of sight at that redshift is about 1.7 kpc for a Hubble constant of 50 km/s/Mpc. Note the strong shift between the absorption groups near -400 km/s, in contrast to the nearly identicial appearance of the sharp absorption line near -50 km/s in both images. The spectra were taken with the Keck I telescope and the HIRES spectrograph on Mauna Kea.
The Magnetized Interstellar Medium Home Registration. Hotel Reservation. Excursions. ImportantDates. Program. Proceedings. Lectures. Participants. Antalya. http://www.mpifr-bonn.mpg.de/div/konti/antalya/
Guilaine Lagache WEB Page o. Cambresy et al. (2001) use the difference in spectral energy distribution, warm for the diffuse atomic medium, cold for the Polaris cloud, to separate http://www.ias.fr/PPERSO/glagache/act/ISM_index.html
Extractions: o. The optical properties of the dust grains in such cold clouds has been studied by Stepnik et al. (2002). They show that grain-grain coagulation into fluffy aggregates may occur inside the filament, explaining both the deficit of small grain abundance and the submm emissivity enhancement (by a factor of about 3) of the large grains in such cold filaments. o. Cambresy et al. (2001) use the difference in spectral energy distribution, " warm" for the diffuse atomic medium, "cold" for the Polaris cloud, to separate their respective contribution to the line of sight integrated infrared emission and find that the tau_FIR/ A_V of "cold" dust in Polaris is on average 4 times higher than the Schlegel et al. (1998) value for dust in atomic cirrus. This change in dust property could be interpreted, as in Stepnik et al., by a growth of fluffy particles within low opacity molecular cirrus clouds such as Polaris.
Index Of /~jonathan/SNR_ISM Parent Directory09Apr-2002 1614 - Apache/1.3.26 Server at lheawww.gsfc.nasa.gov Port 80Index of /~jonathan/SNR_ISM. Name Last modified Size http://lheawww.gsfc.nasa.gov/~jonathan/SNR_ISM/