C-13H3OH in OMC-1

Blake, Geoffrey A.; Sutton, E. C.; Masson, C. R.; Phillips, T. G.; Herbst, Eric; Plummer, Grant M.; Lucia, Frank C. De

doi:10.1086/162633

Cited by 28 publications

(41 citation statements)

References 15 publications

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“…Both line frequencies were covered by the receiver band. Unfortunately, the most intense line is blended with the 5 Ϫ2 3 4 Ϫ2 and 5 2 3 4 2 13 CH 3 OH E lines (see Blake et al 1984). In order to determine an upper limit to the 13 CH 3 OH emission, we have observed the 5 1 3 4 1 methanol line toward the PDR peak.…”

Section: Observations and Resultsmentioning

confidence: 99%

Detection of CO[TSUP]+[/TSUP] toward the Reflection Nebula NGC 7023

Fuente

Martı́n-Pintado

1997

The Astrophysical Journal

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We have detected CO ϩ toward the photon-dominated region (PDR) associated with the reflection nebula NGC 7023. This is the first detection of CO ϩ in the vicinity of a Be star. A CO ϩ column density of 3 ϫ 10 11 cm Ϫ2has been derived toward the PDR peak. However, we have not detected CO ϩ in a well-shielded clump of the adjacent molecular cloud, where the CO ϩ ͞HCO ϩ abundance ratio is at least 100 times lower than in the PDR. Our results show, for the first time, that CO ϩ column densities as large as 3 ϫ 10 11 cm Ϫ2 can be produced in regions with incident UV fields of just a few 10 3 (in units of Habing field) and densities of Յ10 5 cm Ϫ3 . Furthermore, since the ionization potential of CO is larger than 13.6 eV, our data rule out the direct photoionization of CO as a significant CO ϩ formation mechanism.

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Section: Observations and Resultsmentioning

confidence: 99%

Detection of CO[TSUP]+[/TSUP] toward the Reflection Nebula NGC 7023

Fuente

Martı́n-Pintado

1997

The Astrophysical Journal

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“…The entry for the 18 O species was prepared by one of us (HSPM). Transitions in the range of our survey were taken mainly from Lees & Baker (1968), Pickett et al (1981), Herbst et al (1984), Sastry et al (1984), Anderson et al (1990a), , and Xu et al (2008) for the main isotopologue, from Haque et al (1974), Blake et al (1984), Kuriyama et al (1986), Anderson et al (1987), and Anderson et al (1990b) for 13 CH 3 OH, and from Ikeda et al (1998) for CH 3 18 OH.…”

Section: Methanol Ch 3 Ohmentioning

confidence: 93%

Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)

Беллоче

Müller

Menten

et al. 2013

A&A

385

523

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Context. The discovery of amino acids in meteorites fallen to Earth and the detection of glycine, the simplest of them, in samples returned from a comet to Earth strongly suggest that the chemistry of the interstellar medium is capable of producing such complex organic molecules and that they may be widespread in our Galaxy. Aims. Our goal is to investigate the degree of chemical complexity that can be reached in the interstellar medium, in particular in dense star-forming regions. Methods. We performed an unbiased, spectral line survey toward Sgr B2(N) and (M), two regions where high-mass stars are formed, with the IRAM 30 m telescope in the 3 mm atmospheric transmission window. Partial surveys at 2 and 1.3 mm were performed in parallel. The spectra were analyzed with a simple radiative transfer model that assumes local thermodynamic equilibrium but takes optical depth effects into account. Results. About 3675 and 945 spectral lines with a peak signal-to-noise ratio higher than 4 are detected at 3 mm toward Sgr B2(N) and (M), i.e. about 102 and 26 lines per GHz, respectively. This represents an increase by about a factor of two over previous surveys of Sgr B2. About 70% and 47% of the lines detected toward Sgr B2(N) and (M) are identified and assigned to 56 and 46 distinct molecules as well as to 66 and 54 less abundant isotopologues of these molecules, respectively. In addition, we report the detection of transitions from 59 and 24 catalog entries corresponding to vibrationally or torsionally excited states of some of these molecules, respectively, up to a vibration energy of 1400 cm −1 (2000 K). Excitation temperatures and column densities were derived for each species but should be used with caution. The rotation temperatures of the detected complex molecules typically range from ∼50 to 200 K. Among the detected molecules, aminoacetonitrile, n-propyl cyanide, and ethyl formate were reported for the first time in space based on this survey, as were five rare isotopologues of vinyl cyanide, cyanoacetylene, and hydrogen cyanide. We also report the detection of transitions from within twelve new vibrationally or torsionally excited states of known molecules. Absorption features produced by diffuse clouds along the line of sight are detected in transitions with low rotation quantum numbers of many simple molecules and are modeled with ∼30-40 velocity components with typical linewidths of ∼3-5 km s −1 . Conclusions. Although the large number of unidentified lines may still allow future identification of new molecules, we expect most of these lines to belong to vibrationally or torsionally excited states or to rare isotopologues of known molecules for which spectroscopic predictions are currently missing. Significant progress in extending the inventory of complex organic molecules in Sgr B2(N) and deriving tighter constraints on their location, origin, and abundance is expected in the near future thanks to an ongoing spectral line survey at 3 mm with ALMA in its cycles 0 and 1. The present single-dish surve...

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“…From a single-dish measurement of the optically thin isotopologue 13 CH 3 OH Blake et al (1984) derived a rotational temperature of 120 K averaged over their 30 beam. This is close to the 140 K derived for CH 3 OH by Johansson et al (1984) with a similar beam.…”

Section: From Single-dish Methyl Formate and Methanol Studiesmentioning

confidence: 99%

HCOOCH₃as a probe of temperature and structure in Orion-KL

Favre

Despois

Brouillet

et al. 2011

A&A

100

238

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Context. The Orion Kleinmann-Low nebula (Orion-KL) is a complex region of star formation. Whereas its proximity allows studies on a scale of a few hundred AU, spectral confusion makes it difficult to identify molecules with low abundances. Aims. We studied an important oxygenated molecule, HCOOCH 3 , to characterize the physical conditions, temperature, and density of the different molecular source components. Methyl formate presents strong close rotational transitions covering a wide range of energy, and its emission in Orion-KL is not contaminated by the emission of N-bearing molecules. This study will help in the future 1) to constrain chemical models for the formation of methyl formate in gas phase or on grain mantles and 2) to search for more complex or prebiotic molecules. Methods. We used high-resolution observations from the IRAM Plateau de Bure Interferometer to reduce spectral confusion and to better isolate the molecular emission regions. We used twelve data sets with a spatial resolution down to 1.8 × 0.8 . Continuum emission was subtracted by selecting apparently line-free channels. Results. We identify 28 methyl formate emission peaks throughout the 50 field of observations. The two strongest peaks, named MF1 and MF2, are in the Compact Ridge and in the southwest of the Hot Core, respectively. From a comparison with single-dish observations, we estimate that we miss less than 15% of the flux and that spectral confusion is still prevailing as half of the expected transitions are blended over the region. Assuming that the transitions are thermalized, we derive the temperature at the five main emission peaks. At the MF1 position in the Compact Ridge we find a temperature of 80 K in a 1.8 × 0.8 beam size and 120 K on a larger scale (3.6 × 2.2 ), suggesting an external source of heating, whereas the temperature is about 130 K at the MF2 position on both scales. Transitions of methyl formate in its first torsionally excited state are detected as well, and the good agreement of the positions on the rotational diagrams between the ground state and the v t = 1 transitions suggests a similar temperature. The LSR velocity of the gas is between 7.5 and 8.0 km s −1 depending on the positions and column density peaks vary from 1.6 × 10 16 to 1.6 × 10 17 cm −2 . A second velocity component is observed around 9−10 km s −1 in a north-south structure stretching from the Compact Ridge up to the BN object, and this component is warmer at the MF1 peak. The two other C 2 H 4 O 2 isomers are not detected, and the derived upper limit for the column density is ≤3 × 10 14 cm −2 for glycolaldehyde and ≤2 × 10 15 cm −2 for acetic acid. From the 223 GHz continuum map, we identify several dust clumps with associated gas masses in the range 0.8 to 5.8 M . Assuming that the methyl formate is spatially distributed as the dust is, we find relative abundances of methyl formate in the range ≤0.1 × 10 −8 to 5.2 × 10 −8 . We suggest a relation between the methyl formate distribution and shocks as traced by 2.12 μm H 2 emission.

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C-13H3OH in OMC-1

Cited by 28 publications

References 15 publications

Detection of CO[TSUP]+[/TSUP] toward the Reflection Nebula NGC 7023

Detection of CO[TSUP]+[/TSUP] toward the Reflection Nebula NGC 7023

Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)

HCOOCH₃as a probe of temperature and structure in Orion-KL

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C-13H3OH in OMC-1

Cited by 28 publications

References 15 publications

Detection of CO[TSUP]+[/TSUP] toward the Reflection Nebula NGC 7023

Detection of CO[TSUP]+[/TSUP] toward the Reflection Nebula NGC 7023

Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)

HCOOCH3as a probe of temperature and structure in Orion-KL

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HCOOCH₃as a probe of temperature and structure in Orion-KL