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Topic: Interstellar reddening

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Interstellar Medium: Cold Maps of interstellar reddening demonstrated that the interstellar medium is composed mostly of hydrogen and helium gas (99%) and traces of dust. Radiation from interstellar molecules is a good tracer of the dense, thick regions of the interstellar medium. We divide the interstellar medium into three types dependent on their temperature (called the phase of the interstellar medium): cold (10's K), warm (100 to 1000's K), hot (millions K). zebu.uoregon.edu /~js/ast122/lectures/lec22.html   (1441 words)

The Interstellar Medium The effect of dust is to dim the light from distant objects (interstellar extinction) in the Galaxy and redden the colors (interstellar reddening) because red light is not scattered as efficiently as blue light. The interstellar medium is far too cool to excite the UV or optical transitions of hydrogen, but there is a feature at 21 cm wavelength in the radio produced by the spins (magnetic fields) of the hydrogen atom's nuclear proton and orbiting electron. Although the interstellar medium is, by several orders of magnitude, a better vacuum than any physicists can create in the laboratory there is still about of 5-10 billion M cassfos02.ucsd.edu /public/tutorial/ISM.html   (1162 words)

Interstellar medium - Wikipedia, the free encyclopedia The medium is also responsible for extinction and reddening, the decreasing light intensity and dominant observable wavelengths of a star as the light travels through the medium. The interstellar medium is usually divided into three phases, depending on the temperature of the gas: hot (millions of kelvins), warm (thousands of kelvins), and cold (tens of kelvins). In astronomy, the interstellar medium (or ISM) is the matter (interstellar matter, also abbreviated by ISM) and energy (interstellar radiation field, ISRF) content that exists between the stars within a galaxy. en.wikipedia.org /wiki/Interstellar_medium   (946 words)

Interstellar Medium: Cold Maps of interstellar reddening demonstrated that the interstellar medium is composed mostly of hydrogen and helium gas (99%) and traces of dust. Radiation from interstellar molecules is a good tracer of the dense, thick regions of the interstellar medium. We divide the interstellar medium into three types dependent on their temperature (called the phase of the interstellar medium): cold (10's K), warm (100 to 1000's K), hot (millions K). abyss.uoregon.edu /~js/ast122/lectures/lec22.html   (1441 words)

04.02.2003 - Cosmic chemistry inside interstellar clouds points to galactic wind of low-energy rays "Interstellar chemistry is very important in that it helps determine certain properties of the galaxy, in particular the intensity of the low-energy part of the cosmic ray spectrum," said Al Glassgold, professor emeritus of physics at New York University and now adjunct professor of astronomy at UC Berkeley. Unlike dense clouds, which look black and empty because the dust and gas block the light of stars forming inside, diffuse clouds are invisible, betrayed only by the reddening of stars whose light passes through them. To measure the reaction rate at a temperature closer to that found in the interstellar medium, McCall teamed up with UC Berkeley chemist Richard Saykally, who has pioneered the use of novel infrared laser technologies for the study of ionized molecules in the laboratory. www.berkeley.edu /news/media/releases/2003/04/02_cosmic.shtml   (1478 words)

Interstellar Medium: Cold Maps of interstellar reddening demonstrated that the interstellar medium is composed mostly of hydrogen and helium gas (99%) and traces of dust. Most of the interstellar medium is in the form of neutral hydrogen gas (HI). Dust, in an interstellar sense, is very small (few microns in size) particles of carbon and silicon. zebu.uoregon.edu /~js/ast122/lectures/lec22.html   (1441 words)

The Interstellar Medium The effect of dust is to dim the light from distant objects (interstellar extinction) in the Galaxy and redden the colors (interstellar reddening) because red light is not scattered as efficiently as blue light. The interstellar medium is far too cool to excite the UV or optical transitions of hydrogen, but there is a feature at 21 cm wavelength in the radio produced by the spins (magnetic fields) of the hydrogen atom's nuclear proton and orbiting electron. Although the interstellar medium is, by several orders of magnitude, a better vacuum than any physicists can create in the laboratory there is still about of 5-10 billion M cassfos02.ucsd.edu /public/tutorial/ISM.html   (1162 words)

The Interstellar Medium The effect of dust is to dim the light from distant objects (interstellar extinction) in the Galaxy and redden the colors (interstellar reddening) because red light is not scattered as efficiently as blue light. The interstellar medium is far too cool to excite the UV or optical transitions of hydrogen, but there is a feature at 21 cm wavelength in the radio produced by the spins (magnetic fields) of the hydrogen atom's nuclear proton and orbiting electron. Dust is responsible for the blue haze around the Pleiades star cluster (Messier Database, (Web Nebulae); this nebulosity is called a reflection nebula resulting from blue light from the hot B-stars being scattered toward us from dust surrounding the cluster stars. cassfos02.ucsd.edu /public/tutorial/ISM.html   (1162 words)

Chapter13  Interstellar Matter and Star Formation We can tell the amount of reddening that happens because of the interstellar medium by looking at a star& spectra to determine its temperature and color and then compare this to the actual color observed. So the dust amounts to only about 1 to 10 percent of the total mass of the interstellar matter. interstellar gas - atoms, molecules, and ions in the interstellar medium- it is mostly made of hydrogen and tends to clump into clouds www.efc.dcccd.edu /smpe/faculty/adjunct/chafey/chapter13.htm   (1162 words)

Interstellar reddening The interstellar reddening and distance of Nova Cygni 1975 /V1500 Cygni/... Lecture 8:The ISM- Nebula and Interstellar Dust Bunnies... Interstellar extinction law near the Galactic equator along the Camelopardalis,... www.scienceoxygen.com /signal/275.html   (1162 words)

Centaurus A This effect against stars in our own galaxy is known as interstellar reddening, though the effect in galaxies is complicated by the fact that some of the light is not in fact absorbed but scattered in different directions upon encountering a dust grain. The peculiar radio galaxy Centaurus A (NGC 5128) provides a striking example of how dust can affect our view of a galaxy, and how going to redder wavelengths helps penetrate interstellar dust. This color-composite CCD image (from B, V, and R-band frames obtained with the 1.5-meter telescope at Cerro Tololo) shows at once the reddening effects of dust in the strong dust lane, some red emission from ionized gas at the H-alpha line, and blue regions of star formation along the dust lane. crux.astr.ua.edu /gifimages/cena.html   (239 words)

Centaurus A This effect against stars in our own galaxy is known as interstellar reddening, though the effect in galaxies is complicated by the fact that some of the light is not in fact absorbed but scattered in different directions upon encountering a dust grain. The peculiar radio galaxy Centaurus A (NGC 5128) provides a striking example of how dust can affect our view of a galaxy, and how going to redder wavelengths helps penetrate interstellar dust. This color-composite CCD image (from B, V, and R-band frames obtained with the 1.5-meter telescope at Cerro Tololo) shows at once the reddening effects of dust in the strong dust lane, some red emission from ionized gas at the H-alpha line, and blue regions of star formation along the dust lane. crux.astr.ua.edu /gifimages/cena.html   (239 words)

Astron. Astrophys. 356, 118-126 (2000) A large part of the values of interstellar reddening of the stars in NGC 6913 from spectral classification are quite different from those taken from photometry (especially for early B and F type stars); the largest discrepancy amounts to 1.48 mag.. Reddening is estimated on the basis of spectral classification. Spectral classification and reddening in the young open cluster NGC 6913 aa.springer.de /bibs/0356001/2300118/small.htm   (239 words)

73.hrs The measurement of the DIB are required for determination of the interstellar reddening if the photometric F system is used (see a section below.) ===== 3. Discussion of a report by U. Munari A report on the diffuse interstellar band (DIB) at 862 nm by U. Munari (UM) has been received on 12.01.2000 through the DMS system. It would be interesting and necessary for a realistic discussion if an estimate were made of the precision of interstellar absorption measured by this method with GAIA. www.astro.ku.dk /~erik/gaia/73.hrs   (239 words)

Astron. Astrophys. 326, 831-841 (1997) It is clear, in brief, that there are two distinct and disparate colour regimes, neither of which is consistent with normal reddening trends for the interstellar medium (denoted ISM in Fig. colour map over the envelope of IRAS 09371+1212, where we note evidence for enhanced reddening in the nucleus extending asymmetrically towards the east, and a partial annulus of reduced reddening exterior to the inner bright core. Finally, it is frequently proposed that such changes in colour index arise from preferential obscuration by collimating disks - a presumption which has been liberally applied to the present source. aa.springer.de /papers/7326002/2300831/sc3.htm   (239 words)

Session C9 - Tests of Physics Laws. The cause of interstellar reddening, blue skys and red sunsets is often presented with the identical explanation: Rayleigh scattering off of dust particles with sizes small compared to the wavelength of light. In this presentation, we will discuss the differences between the actual sources of Rayleigh scattering in a variety of settings as varied as liquids, solids, gasses and the interstellar medium. In the semiclassical approximation in which the electric charges of scalar particles are described by Grassmann variables (Q_i^2=0,\ Q_iQ_j\ne 0), it is possible to re-express the Lienard-Wiechert potentials and electric fields in the radiation gauge as phase space functions, because the difference among retarded, advanced, and symmetric Green functions is of order Q_i^2. flux.aps.org /meetings/YR01/APR01/abs/S390.html   (1689 words)

Hanson/Frisch Scientific Visualizations The Local Bubble wall positions are based on the reddening of starlight, based on Lucke (1978, Astronomy and Astrophysics, v74, p367). (Or, alternatively see this page.) Visualization of the Local Fluff, (or see URL) based on the assumption that the LSR velocity vector of the interstellar cloud surrounding the solar sytem is parallel to the surface normal (Frisch, 1994, Science, v265,p1423, "Morphology and Ionization of the Interstellar Cloud Surrounding the Solar System"). Visualization of Local Bubble, showing the molecular clouds delimiting Local Bubble walls in the galactic center hemisphere. astro.uchicago.edu /~frisch/visualization.html   (1689 words)

Science News: Dusting the galaxy - cosmic dust Cosmic dust is one of the two major inhabitants of interstellar space in our and other galaxies (gas clouds are the other). In visible light the dust manifests its presence in a negative, subtractional way by absorbing light and so dimming and reddening the appearance of stars. From all this Mauche and Gorenstein could calculate that approximately all of the silicon, magnesium and iron and 60 percent of the carbon in the interstellar medium is locked up in dust grains. www.findarticles.com /p/articles/mi_m1200/is_v128/ai_3869769   (1689 words)

Supernova 2004dj in NGC 2403 Following previous work [3], we assume that the empirical relation between the equivalent width of Na I D1 and interstellar reddening in our Galaxy [4] is also representative for the interstellar medium in NGC 2403. H-alpha image of NGC 2403 obtained with the Tautenburg Schmidt focus CCD camera on August 10, 2004 by B. Stecklum. H-alpha image of NGC 2403 obtained with the Tautenburg Schmidt focus CCD camera in 2003. www.tls-tautenburg.de /research/klose/SN2004dj.html   (441 words)

M24 - Small Sagittarius Star Cloud It is of interest that the stars in the Small Sagittarius Star Cloud are slightly more blue-colored than in other galactic windows, this is probably due to a large population of young stars and less obscuration by reddening interstellar dust. It is one of the windows where our view towards the center of the Milky Way is less obscured by dust than elsewhere, we can see a huge star cloud in that chance tunnel in the interstellar dust. M24, the Small Sagittarius Star Cloud, is not an open star cluster; in fact it is not a "true" deep-sky object at all. www.astro.univie.ac.at /~koprolin/Photo/GalClu/M24.html   (441 words)

Interstellar reddening Reddening and age for 13 southern Galactic open clusters determined from integra... www.scienceoxygen.com /signal/275.html   (441 words)

qual_outline.html 21 cm radiation Stimulated vs. spontaneous decay Equation of detailed balancing 4 major phases of ISM Density Temperature Pressure Ionization states Distribution Detection techniques Absorption properties with respect to wavelength Balmer and Paschen lines as measure of reddening (elec. Interstellar Medium HII regions Detailed balancing vs Rosselind uncompensated cycles Milne relations Stromgren spheres Spectral features Milky Way vs. Magellanic Clouds Wolf-Rayet bubbles Formation Planetary Nebulae Spectral features Ionization equilibrium (and statistical equilibrium) Saha equation -- why is it not a good appx. personal.tcu.edu /~dingram/edu/qual_outline.html   (441 words)

Nebulae Absorption Nebulae or Dark Nebulae: Absorb light: Their gas component can be seen as absorption spectra in the light of background stars, their dust component by absorbing and reddening background light. These nebulae quickly expand and fade while their matter is spread in the interstellar surroundings. Emission Nebulae: Emit light because the atoms in their gases are excited by high energy radiation of stars involved. www.seds.org /messier/nebula.html   (731 words)

Supernova SN 2004et Sharp interstellar Na I absorption lines are observed at heliocentric radial velocities of -21.1 (+/- 0.7) and +45.2 (+/- 0.4) km/s, matching expectation for separate origin within our galaxy and NGC 6946. 28, which suggests that it is a young type II SN, affected some reddening by both in our Galaxy and in NGC 6946; total amount of E(B-V) is estimated as 0.41 mag. NGC 6946 is one of the most SN productive galaxies (SNe 1917A, 1939C, 1948B, 1968D, 1969P, 1980K and 2002hh), then SN 2004et is the eighth SN in one galaxy (new record!). www.nvg.ntnu.no /org/taf/nyheter/sn2004et.htm   (731 words)

4 Results However in summary, the present analysis shows that the optimized structural model designed in Papers I and II also successfully accommodates the data in fields with more special characteristics, such as interstellar reddening and enhanced stellar space density and population mix in the inner Galaxy. Qualitatively, the low(er) scale height of the young stars is consistent with (current) massive-star formation in the inner disk being confined to regions of lower thickness than in the outer Galaxy, as shown in the recent study of the radial distribution of OB star formation by Bronfman et al. Representative plots of thin-disk parameters are illustrated for the field NGC 6171 in Fig. aanda.u-strasbg.fr:2002 /papers/aa/full/2001/03/aa10143/node4.html   (1191 words)

The Bruce Medalists: Joel Stebbins He and his colleagues, especially Albert Whitford, used the new technique to investigate eclipsing binaries, the reddening of starlight by interstellar dust, colors of galaxies, all kinds of variable stars, and the sun. After studies at the Universities of Nebraska and Wisconsin, Joel Stebbins earned the third Ph.D. in astronomy granted by the University of California. He directed the University of Illinois Observatory from 1903 to 1922 and the University of Wisconsin’s Washburn Observatory from 1922 to 1948, then spent another decade on research at the Lick Observatory. www.phys-astro.sonoma.edu /BruceMedalists/Stebbins/index.html   (202 words)

Joel Stebbins Stebbins used the new technique to investigate eclipsing binaries, the reddening of starlight by interstellar dust, colors of galaxies, and variable stars. Stebbins was awarded the Bruce Medal by the Astronomical Society of the Pacific in 1941, and the Henry Norris Russell Lectureship of the American Astronomical Society in 1956. Stebbins brought photoelectric photometry from its infancy in the early 1900s to a mature technique by the 1950s, when it succeeded photography as the primary method of photometry. www.serebella.com /encyclopedia/article-Joel_Stebbins.html   (499 words)

NOAOpre Barentine, J.C. Bernard's Merope Nebula (IC 349): An interstellar interloper Massey, P., and Armandroff, T.E. The massive star content, reddening, and distance of the nearby irregular galaxy IC 10 Giampapa, M.S., Prosser, C.F., and Fleming, T.A. X-ray activity in the open cluster IC 4665 www.noao.edu /noao/library/noaopre.html   (499 words)

Constraints on the Circumstellar Disk Masses in the IC 348 Cluster In each panel, the solid curves represent the locus of main-sequence and giant stars (Bessell & Brett 1988) and the dashed line is the interstellar reddening vector (Cohen etal. This figure shows that none of the known IC 348 stars were detected in the lambda 3mm continuum at the 3sigma noise level or greater. The mean flux observed toward the 95 IC 348 members is 0.22 ± 0.08 mJy, where the uncertainty is the standard deviation of the mean. www.astro.caltech.edu /~jmc/papers/ic348   (499 words)

Ophiuchus A study of interstellar reddening in a region in Ophiuchus (Lunds universitet. A study of the distribution of the stars in the Sagittarius and Ophiuchus regions of the Milky Way (Lembang, Java. New variable stars in four globular clusters in Ophiuchus (Publications of the David Dunlap Observatory, University of Toronto) www.veryhappening.com /things/ophiuchus   (499 words)

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