Near-infrared spectrophotometry of polarized compact infrared sources

Joyce, R. R.; Simon, T.

doi:10.1086/160282

Cited by 12 publications

(4 citation statements)

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“…These objects are all well clustered in the two-color diagram and after taking into account the %30 mag of visual extinction toward the GC, these objects fall close to the location of hot and massive stars near the main sequence. The Joyce & Simon (1982) and Willner et al (1982). Their photometric data are taken from the infrared catalog by Gezari et al (1993).…”

Section: The New Ir-excess Sourcesmentioning

confidence: 99%

Young Stars at the Center of the Milky Way?

Eckart

Moultaka

Viehmann

et al. 2004

ApJ

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We present results from the first diffraction-limited images of the Galactic center (GC) at 1.6, 2.1, and 3.8 m with the new adaptive optics (AO) camera NAOS/CONICA at the ESO Very Large Telescope, as well as 3-4 m low-resolution spectroscopy. We have discovered a small (0.13 lt-yr diameter) cluster of compact sources about 0B5 north of IRS 13 with strong IR excesses due to T > 500 K dust. The nature of the sources is unclear. They may be a cluster of highly extincted stars that heat the local environment of the minispiral. We also consider an explanation that involves the presence of young stars at evolutionary stages between young stellar objects and Herbig Ae/Be objects with ages of about 0.1 to 1 million yr. This scenario would imply more recent star formation in the GC than previously suspected. The AO observations also resolve the central IRS 13 complex. In addition to the previously known bright stars E1 and E2, the K-and L 0 -band images for the first time resolve object E3 into two components, E3N and E3c. The latter one is closest to the 7 mm Very Large Array radio continuum source found at the location of the IRS 13 complex. E3c may be associated with a strong stellar wind or a dusty Wolf-Rayet-like star at that location.

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Section: The New Ir-excess Sourcesmentioning

confidence: 99%

Young Stars at the Center of the Milky Way?

Eckart

Moultaka

Viehmann

et al. 2004

ApJ

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“…W 51/IRS 2 W51/IRS 2 is an infrared source that contains an embedded H II region. It has a 3 km ice absorption band H 2 O previously estimated to have an optical depth q B 0.8 (Soifer, Russell, & Merrill 1976 ;Joyce & Simon 1982). These ice band observations were taken with aperture diameters of 17A and 11A, respectively.…”

Section: Observationsmentioning

confidence: 99%

New 3 Micron Spectra of Young Stellar Objects with H₂O Ice Bands

Brooke

Sellgren

Geballe

1999

ApJ

145

196

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We present new ground-based 3 km spectra of 14 young stellar objects with ice absorption H 2 O bands. The broad absorption feature at 3.47 km was detected toward all objects, and its optical depth is correlated with the optical depth of ice, strengthening an earlier Ðnding. The broad absorption H 2 O feature at 3.25 km was detected toward two more sources, and an upper limit is given for a third source. The optical depths of the 3.25 km feature obtained to date are better correlated with the optical depth of the refractory silicate dust than with that of ice. If this trend is conÐrmed, this would support our H 2 O proposed identiÐcation of the feature as the C-H stretch of aromatic hydrocarbons at low temperature. An absorption feature at 3.53 km due to solid methanol was detected for the Ðrst time toward Mon R2/IRS 2, as well as toward W33A and GL 2136. The wavelengths of the features toward CH 3 OH W33A, GL 2136, and NGC 7538/IRS 9 can be Ðtted by ices, whereas the wavelength of the CH 3 OH-rich feature toward Mon R2/IRS 2 suggests an ice environment. Solid methanol abundances H 2 O-rich toward GL 2136, NGC 7538/IRS 9, and Mon R2/IRS 2 are 3%È5% relative to ice. There is an H 2 O additional narrow absorption feature near 3.47 km toward W33A. For the object W51/IRS 2, spatially resolved spectra from 2 to 4 km indicate that the ice is located predominantly in front of the H 2 O eastern component and that the ice extinction is much deeper than previously estimated. For the H 2 O object RNO 91, spectra from 2 to 4 km reveal stellar (or circumstellar) CO gas absorption and deeper ice extinction than previously estimated. H 2

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“…Indeed, as the characteristic time of photodesorption is around 10 9 s for unshielded regions of di use clouds, which is usually much less than the time of resurfacing, this may considerably increase tL. However, the correlation of polarization with the strength of 3.1 m water ice feature (see Joyce & Simon 1982) testify that the photodesorption cannot provide a universal solution (see also Lee & Draine 1985).…”

Section: Degree Of Alignmentmentioning

confidence: 99%

Physics and chemistry of the Purcell alignment

Lazarian¹

1995

Monthly Notices of the Royal Astronomical Society

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Paramagnetic alignment of suprathermally rotating grains is discussed in view of recent progress in understanding subtle processes taking place over grain surface. It is shown that in typical ISM conditions, grains with surfaces of amorphous H 2 O ice, defected silicate or polymeric carbonaceous material are likely to exhibit enhanced alignment, while those of aromatic carbonaceous material or graphite are not. The critical grain sizes and temperature for the Purcell's alignment are obtained and preferential alignment of large grains is established.

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Near-infrared spectrophotometry of polarized compact infrared sources

Cited by 12 publications

References 0 publications

Young Stars at the Center of the Milky Way?

Young Stars at the Center of the Milky Way?

New 3 Micron Spectra of Young Stellar Objects with H₂O Ice Bands

Physics and chemistry of the Purcell alignment

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Near-infrared spectrophotometry of polarized compact infrared sources

Cited by 12 publications

References 0 publications

Young Stars at the Center of the Milky Way?

Young Stars at the Center of the Milky Way?

New 3 Micron Spectra of Young Stellar Objects with H2O Ice Bands

Physics and chemistry of the Purcell alignment

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Product

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New 3 Micron Spectra of Young Stellar Objects with H₂O Ice Bands