Molecular abundance variations near our galactic center

Y. C. Minh; S. J. Kim; Soojong Pak; Sungho Lee; W. M. Irvine; L. Å Nyman

doi:10.1016/j.newast.2005.03.001

Molecular abundance variations near our galactic center

Y. C. Minh
, S. J. Kim
, Soojong Pak
, Sungho Lee
, W. M. Irvine
, L. Å Nyman

Research output: Contribution to journal › Article › peer-review

8 Citations (Scopus)

Abstract

Millimeter-wave observations of CO, HCO⁺, HNCO, and SiO molecular lines toward Sgr A show that the prominent gas condensations in this region differ significantly in their chemical properties, which may be a result of gradients in the physical conditions as a function of location. HNCO and SiO observations suggest that M - 0.13 - 0.08 (the +20 km s^-1 cloud) appears to consist of two different components, M - 0.13 - 0.08a and M - 0.13 - 0.08b, with LSR velocities of about +25 and +5 km s^-1, respectively. The clump M - 0.13 - 0.08a (the +25 km s^-1 cloud) seems to be located very close to Sgr A East and the observed enhancement of HNCO and SiO may result from the interaction with Sgr A East. The molecular gas clump M - 0.02 - 0.07 (the +50 km s^-1 cloud) shows the strongest ¹³CO emission among the identified clouds in this region, and is the most massive condensation (≥3 × 10⁵ M_⊙), but may be located closer to us than other clouds, since it appears to be chemically quiescent and shade the "inter-cloud region" where the HCO ⁺/¹³CO ratio is enhanced. The -30 km s^-1 component shows a similar morphology to the HCO⁺ enhanced "inter-cloud" region. M + 0.07 - 0.08 and M + 0.11 - 0.08 show strong HCO⁺ 1-0 emission, and appear to consist of one cloud (the HCO ⁺ cloud) in this observation. The HCO⁺/¹³CO abundance ratio is enhanced by a factor of 2-3 toward this HCO⁺ cloud and the inter-cloud region between l = 0.1° and 0° near to Sgr A East, compared to other clouds observed in this region. This relative enhancement of HCO⁺ is thought to result from interaction with Sgr A East.

Original language	English
Pages (from-to)	425-438
Number of pages	14
Journal	New Astronomy
Volume	10
Issue number	5
DOIs	https://doi.org/10.1016/j.newast.2005.03.001
Publication status	Published - Apr 2005

Bibliographical note

Funding Information:
S.J.K. and Y.C.M. acknowledge a partial support from KOSEF (R01-1999-000-00022-0), and W.I. from the NASA Astrobiology Institute through the Goddard Space Flight Center node.

Funding Information:
SEST is operated by Onsala Space Observatory, the Swedish National Facility for Radio Astronomy, with financial support from the Swedish Natural Science Research Council (NFR) and ESO.

Keywords

CO
Gas abundances
HCO
HNCO
Interstellar medium
Interstellar molecules
Sgr A
SiO molecule

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10.1016/j.newast.2005.03.001

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@article{bb624b6db34c46d492463f1dcfded23d,

title = "Molecular abundance variations near our galactic center",

abstract = "Millimeter-wave observations of CO, HCO+, HNCO, and SiO molecular lines toward Sgr A show that the prominent gas condensations in this region differ significantly in their chemical properties, which may be a result of gradients in the physical conditions as a function of location. HNCO and SiO observations suggest that M - 0.13 - 0.08 (the +20 km s-1 cloud) appears to consist of two different components, M - 0.13 - 0.08a and M - 0.13 - 0.08b, with LSR velocities of about +25 and +5 km s-1, respectively. The clump M - 0.13 - 0.08a (the +25 km s-1 cloud) seems to be located very close to Sgr A East and the observed enhancement of HNCO and SiO may result from the interaction with Sgr A East. The molecular gas clump M - 0.02 - 0.07 (the +50 km s-1 cloud) shows the strongest 13CO emission among the identified clouds in this region, and is the most massive condensation (≥3 × 105 M⊙), but may be located closer to us than other clouds, since it appears to be chemically quiescent and shade the {"}inter-cloud region{"} where the HCO +/13CO ratio is enhanced. The -30 km s-1 component shows a similar morphology to the HCO+ enhanced {"}inter-cloud{"} region. M + 0.07 - 0.08 and M + 0.11 - 0.08 show strong HCO+ 1-0 emission, and appear to consist of one cloud (the HCO + cloud) in this observation. The HCO+/13CO abundance ratio is enhanced by a factor of 2-3 toward this HCO+ cloud and the inter-cloud region between l = 0.1° and 0° near to Sgr A East, compared to other clouds observed in this region. This relative enhancement of HCO+ is thought to result from interaction with Sgr A East.",

keywords = "CO, Gas abundances, HCO, HNCO, Interstellar medium, Interstellar molecules, Sgr A, SiO molecule",

author = "Minh, \{Y. C.\} and Kim, \{S. J.\} and Soojong Pak and Sungho Lee and Irvine, \{W. M.\} and Nyman, \{L. {\AA}\}",

note = "Funding Information: S.J.K. and Y.C.M. acknowledge a partial support from KOSEF (R01-1999-000-00022-0), and W.I. from the NASA Astrobiology Institute through the Goddard Space Flight Center node. Funding Information: SEST is operated by Onsala Space Observatory, the Swedish National Facility for Radio Astronomy, with financial support from the Swedish Natural Science Research Council (NFR) and ESO. ",

year = "2005",

month = apr,

doi = "10.1016/j.newast.2005.03.001",

language = "English",

volume = "10",

pages = "425--438",

journal = "New Astronomy",

issn = "1384-1076",

publisher = "Elsevier B.V.",

number = "5",

}

TY - JOUR

T1 - Molecular abundance variations near our galactic center

AU - Minh, Y. C.

AU - Kim, S. J.

AU - Pak, Soojong

AU - Lee, Sungho

AU - Irvine, W. M.

AU - Nyman, L. Å

N1 - Funding Information: S.J.K. and Y.C.M. acknowledge a partial support from KOSEF (R01-1999-000-00022-0), and W.I. from the NASA Astrobiology Institute through the Goddard Space Flight Center node. Funding Information: SEST is operated by Onsala Space Observatory, the Swedish National Facility for Radio Astronomy, with financial support from the Swedish Natural Science Research Council (NFR) and ESO.

PY - 2005/4

Y1 - 2005/4

N2 - Millimeter-wave observations of CO, HCO+, HNCO, and SiO molecular lines toward Sgr A show that the prominent gas condensations in this region differ significantly in their chemical properties, which may be a result of gradients in the physical conditions as a function of location. HNCO and SiO observations suggest that M - 0.13 - 0.08 (the +20 km s-1 cloud) appears to consist of two different components, M - 0.13 - 0.08a and M - 0.13 - 0.08b, with LSR velocities of about +25 and +5 km s-1, respectively. The clump M - 0.13 - 0.08a (the +25 km s-1 cloud) seems to be located very close to Sgr A East and the observed enhancement of HNCO and SiO may result from the interaction with Sgr A East. The molecular gas clump M - 0.02 - 0.07 (the +50 km s-1 cloud) shows the strongest 13CO emission among the identified clouds in this region, and is the most massive condensation (≥3 × 105 M⊙), but may be located closer to us than other clouds, since it appears to be chemically quiescent and shade the "inter-cloud region" where the HCO +/13CO ratio is enhanced. The -30 km s-1 component shows a similar morphology to the HCO+ enhanced "inter-cloud" region. M + 0.07 - 0.08 and M + 0.11 - 0.08 show strong HCO+ 1-0 emission, and appear to consist of one cloud (the HCO + cloud) in this observation. The HCO+/13CO abundance ratio is enhanced by a factor of 2-3 toward this HCO+ cloud and the inter-cloud region between l = 0.1° and 0° near to Sgr A East, compared to other clouds observed in this region. This relative enhancement of HCO+ is thought to result from interaction with Sgr A East.

AB - Millimeter-wave observations of CO, HCO+, HNCO, and SiO molecular lines toward Sgr A show that the prominent gas condensations in this region differ significantly in their chemical properties, which may be a result of gradients in the physical conditions as a function of location. HNCO and SiO observations suggest that M - 0.13 - 0.08 (the +20 km s-1 cloud) appears to consist of two different components, M - 0.13 - 0.08a and M - 0.13 - 0.08b, with LSR velocities of about +25 and +5 km s-1, respectively. The clump M - 0.13 - 0.08a (the +25 km s-1 cloud) seems to be located very close to Sgr A East and the observed enhancement of HNCO and SiO may result from the interaction with Sgr A East. The molecular gas clump M - 0.02 - 0.07 (the +50 km s-1 cloud) shows the strongest 13CO emission among the identified clouds in this region, and is the most massive condensation (≥3 × 105 M⊙), but may be located closer to us than other clouds, since it appears to be chemically quiescent and shade the "inter-cloud region" where the HCO +/13CO ratio is enhanced. The -30 km s-1 component shows a similar morphology to the HCO+ enhanced "inter-cloud" region. M + 0.07 - 0.08 and M + 0.11 - 0.08 show strong HCO+ 1-0 emission, and appear to consist of one cloud (the HCO + cloud) in this observation. The HCO+/13CO abundance ratio is enhanced by a factor of 2-3 toward this HCO+ cloud and the inter-cloud region between l = 0.1° and 0° near to Sgr A East, compared to other clouds observed in this region. This relative enhancement of HCO+ is thought to result from interaction with Sgr A East.

KW - CO

KW - Gas abundances

KW - HCO

KW - HNCO

KW - Interstellar medium

KW - Interstellar molecules

KW - Sgr A

KW - SiO molecule

UR - https://www.scopus.com/pages/publications/16344367933

U2 - 10.1016/j.newast.2005.03.001

DO - 10.1016/j.newast.2005.03.001

M3 - Article

AN - SCOPUS:16344367933

SN - 1384-1076

VL - 10

SP - 425

EP - 438

JO - New Astronomy

JF - New Astronomy

IS - 5

ER -

Molecular abundance variations near our galactic center

Abstract

Bibliographical note

Keywords

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