Some Results with the COUDÉ Spectrograph of the Mount Wilson Observatory.

Adams, W. S.

doi:10.1086/144237

Cited by 205 publications

(92 citation statements)

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“…In fact, NaH has never been detected in the ISM or CSM even in more modern studies. [15] The presence of CH and CN was clearly corroborated shortly thereafter by Walter S. Adams using the Mount Wilson Observatory [16] famed for its use by Edwin Hubble to determine the expanding universe. Adams noted that there were still many, many other bands left in Merrill's survey that were not attributable at the time.…”

Section: The Origins Of Astrochemistrymentioning

confidence: 91%

Quantum astrochemical spectroscopy

Fortenberry

2016

Int J of Quantum Chemistry

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In this review, the origins of astrochemistry and the initial applications of quantum chemistry to the discovery of new molecules in space are discussed. Furthermore, more recent successes and failures of quantum astrochemistry are explored. Finally, the application of quantum chemistry to the chemical study of space is driving developments in large-scale computational science. Consequently, cloud computing and large molecule computations are discussed. Astrochemistry is a natural application of quantum chemistry. The ability to analyze routinely and completely the structural, spectroscopic, and electronic properties of any given molecule, regardless of its laboratory stability, make this tool a necessary component for astrochemical analysis. The sizes of the computations scaling with the number of electrons and degrees-of-freedom can become limiting, but proper choices of methods can provide unique insights. The chemistry of the Earth is a small snapshot of the chemistries available in the universe at large, and the flexibility inherent within computation make quantum chemistry an excellent driver of new knowledge in fundamental molecular science as well as in astrophysics.

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Section: The Origins Of Astrochemistrymentioning

confidence: 91%

Quantum astrochemical spectroscopy

Fortenberry

2016

Int J of Quantum Chemistry

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“…They can be fitted with a spinning dust spectrum shifted to peak at higher frequencies than standard models, but still within the range of plausible interstellar parameters (e.g., Planck Collaboration XX 2011; Planck Collaboration Int. XV 2014).The Sh2-27 spinning dust is likely to be associated with the famous translucent cloud in which interstellar molecules were first discovered, as absorption lines in the spectrum of the ionizing star ζ Oph (Adams 1941). In fact, many bright H ii regions show negative residuals, e.g., the California nebula (l, b) = (161 • , −13 • ), Orion A and B (l, b) = (210 • , −19 • ) and (207 • , −17 • ), and many of the bright nebulae along the Galactic plane.…”

Section: A First Look At the Low-frequency Foregrounds Using Constraimentioning

confidence: 99%

Planck2015 results

Ade

Aghanim

Alves

et al. 2016

A&A

163

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We discuss the Galactic foreground emission between 20 and 100 GHz based on observations by Planck and WMAP. The total intensity in this part of the spectrum is dominated by free-free and spinning dust emission, whereas the polarized intensity is dominated by synchrotron emission. The Commander component-separation tool has been used to separate the various astrophysical processes in total intensity. Comparison with radio recombination line templates verifies the recovery of the free-free emission along the Galactic plane. Comparison of the high-latitude Hα emission with our free-free map shows residuals that correlate with dust optical depth, consistent with a fraction (≈30%) of Hα having been scattered by high-latitude dust. We highlight a number of diffuse spinning dust morphological features at high latitude. There is substantial spatial variation in the spinning dust spectrum, with the emission peak (in I ν ) ranging from below 20 GHz to more than 50 GHz. There is a strong tendency for the spinning dust component near many prominent H ii regions to have a higher peak frequency, suggesting that this increase in peak frequency is associated with dust in the photo-dissociation regions around the nebulae. The emissivity of spinning dust in these diffuse regions is of the same order as previous detections in the literature. Over the entire sky, the Commander solution finds more anomalous microwave emission (AME) than the WMAP component maps, at the expense of synchrotron and free-free emission. This can be explained by the difficulty in separating multiple broadband components with a limited number of frequency maps. Future surveys, particularly at 5-20 GHz, will greatly improve the separation by constraining the synchrotron spectrum. We combine Planck and WMAP data to make the highest signal-to-noise ratio maps yet of the intensity of the all-sky polarized synchrotron emission at frequencies above a few GHz. Most of the high-latitude polarized emission is associated with distinct large-scale loops and spurs, and we re-discuss their structure. We argue that nearly all the emission at 40 • > l > −90 • is part of the Loop I structure, and show that the emission extends much further in to the southern Galactic hemisphere than previously recognised, giving Loop I an ovoid rather than circular outline. However, it does not continue as far as the "Fermi bubble/microwave haze", making it less probable that these are part of the same structure. We identify a number of new faint features in the polarized sky, including a dearth of polarized synchrotron emission directly correlated with a narrow, roughly 20 • long filament seen in Hα at high Galactic latitude. Finally, we look for evidence of polarized AME, however many AME regions are significantly contaminated by polarized synchrotron emission, and we find a 2σ upper limit of 1.6% in the Perseus region.

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“…The diatomic hydrides CH and CH + were, along with CN, the first molecules to be identified from their optical absorption spectra in diffuse molecular clouds, some 75 years ago (McKellar 1940;Adams 1941;Douglas & Herzberg 1941). Advances in detector technologies and observing techniques now make the optical lines readily observable toward bright background stars (e.g., Crane et al 1995;Zsargó & Federman 2003;Le Petit et al 2004;Shaw et al 2006;Nehmé et al 2008;Boissé et al 2009), yet fundamental carbon chemistry involving C + , CH, and CH + in interstellar gas is not well enough understood to explain the observed abundances of CH + in particular.…”

Section: Introductionmentioning

confidence: 99%

HERSCHEL/HIFI SPECTRAL MAPPING OF C⁺, CH⁺, AND CH IN ORION BN/KL: THE PREVAILING ROLE OF ULTRAVIOLET IRRADIATION IN CH⁺ FORMATION

Morris

Gupta

Nagy

et al. 2016

ApJ

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The CH + ion is a key species in the initial steps of interstellar carbon chemistry. Its formation in diverse environments where it is observed is not well understood, however, because the main production pathway is so endothermic (4280 K) that it is unlikely to proceed at the typical temperatures of molecular clouds. We investigate the formation of this highly reactive molecule with the first velocity-resolved spectral mapping of the CH + J= 1−0, 2−1 rotational transitions, three sets of CH Λ-doubled triplet lines, 12 C + and 13 C + P P , and CH is indicated to arise in the diluted gas, outside the explosive, dense BN/KL outflow. Our models show that UV irradiation provides favorable conditions for steady-state production of CH + in this environment. Surprisingly, no spatial or kinematic correspondences of the observed species are found with H 2 S(1) emission tracing shocked gas in the outflow. We propose that C + is being consumed by rapid production of CO to explain the lack of both C + and CH + in the outflow. Hence, in star-forming environments containing sources of shocks and strong UV radiation, a description of the conditions leading to CH + formation and excitation is incomplete without including the important-possibly dominant-role of UV irradiation.

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Some Results with the COUDÉ Spectrograph of the Mount Wilson Observatory.

Cited by 205 publications

References 0 publications

Quantum astrochemical spectroscopy

Quantum astrochemical spectroscopy

Planck2015 results

HERSCHEL/HIFI SPECTRAL MAPPING OF C⁺, CH⁺, AND CH IN ORION BN/KL: THE PREVAILING ROLE OF ULTRAVIOLET IRRADIATION IN CH⁺ FORMATION

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Some Results with the COUDÉ Spectrograph of the Mount Wilson Observatory.

Cited by 205 publications

References 0 publications

Quantum astrochemical spectroscopy

Quantum astrochemical spectroscopy

Planck2015 results

HERSCHEL/HIFI SPECTRAL MAPPING OF C+, CH+, AND CH IN ORION BN/KL: THE PREVAILING ROLE OF ULTRAVIOLET IRRADIATION IN CH+ FORMATION

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HERSCHEL/HIFI SPECTRAL MAPPING OF C⁺, CH⁺, AND CH IN ORION BN/KL: THE PREVAILING ROLE OF ULTRAVIOLET IRRADIATION IN CH⁺ FORMATION