BIMA CS J=21 Observations of NGC 253: Kinematic Evidence for Dense Gas in a Bar

Peng, R.; Zhou, Shuang; Whiteoak, J. B.; Lo, K. Y.; Sutton, E. C.

doi:10.1086/177913

Cited by 56 publications

(112 citation statements)

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“…According to measurements of CO and CN transitions with the different beam sizes of the 30 m telescope and SEST, we derive an extent of the emitting region of ∼20 (240 pc at a distance of 2.5 Mpc; Mauersberger et al 2003) This is in agreement with the size obtained by Mauersberger et al (2003) from the high angular resolution interferometric maps of CS J = 2−1 of Peng et al (1996). Thus, we can obtain the source averaged brightness temperatures (T B = T MB a The uncertainty is a factor of 2 in both directions, due to the uncertainty of the assumed N(H 2 ) = 1.7 × 10 22 cm −2 (Mauersberger et al 2003).…”

Section: Column Densities and Rotational Temperaturessupporting

confidence: 83%

First detections of extragalactic SO₂, NS and NO

Martín

Mauersberger

Martı́n-Pintado

et al. 2003

A&A

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Abstract.We report the first detections of SO 2 , NS and NO in an extragalactic source, the nucleus of the starburst galaxy NGC 253. Five SO 2 transitions, three groups of hyperfine components of NO and five of NS were detected. All three species show large abundances averaged over the inner 200 pc of NGC 253. With a relative abundance of a few 10 −7 , the emission of the NO molecule is similar or even larger than that found in Galactic star forming regions. The derived relative molecular abundances for each molecule have been compared with those of prototypical Galactic molecular clouds. These results seem to confirm that large scale shocks dominate the chemistry of these molecules in the nucleus of NGC 253, ruling out a chemistry dominated by PDRs for the bulk of the gas.

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Section: Column Densities and Rotational Temperaturessupporting

confidence: 83%

First detections of extragalactic SO₂, NS and NO

Martín

Mauersberger

Martı́n-Pintado

et al. 2003

A&A

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“…A comparison with the approximate rest frequencies of the different groups of lines shows that we mainly see the high velocity component of NGC 253 with a recessional velocity of V LSR ∼ +290 km s −1 (e.g., Martín et al 2006), located several arcseconds southwest of the kinematical center with an extent of order 10 (Mauersberger et al 1996;Peng et al 1996;García-Burillo et al 2000;Paglione et al 2004;Güsten et al 2006;Lebrón et al 2011;Sakamoto et al 2011;Bolatto et al 2013). The similarly extended lower velocity component near 170 km s −1 , mainly arising from several arcseconds northeast of the dynamical center, is too weak to be detected at significant levels (but see Sect.…”

Section: Our Datamentioning

confidence: 88%

Carbon and oxygen isotope ratios in starburst galaxies: New data from NGC 253 and Mrk 231 and their implications

Henkel

Asiri

et al. 2014

A&A

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Carbon and oxygen isotope ratios are excellent measures of nuclear processing, but few such data have been taken toward extragalactic targets so far. Therefore, using the IRAM 30-m telescope, CN and CO isotopologues have been measured toward the nearby starburst galaxy NGC 253 and the prototypical ultraluminous infrared galaxy Mrk 231. Toward the center of NGC 253, the CN and 13 CN N = 1 → 0 lines indicate no significant deviations from expected local thermodynamical equilibrium after accounting for moderate saturation effects (10 and 25%) in the two detected spectral components of the main species. Including calibration uncertainties, which dominate the error budget, the 12 C/ 13 C ratio becomes 40 ± 10. This is larger than the ratio in the central molecular zone of the Galaxy, suggesting a higher infall rate of poorly processed gas toward the central region. Assuming that the ratio also holds for the CO emitting gas, this yields 16 . Also, when accounting for other (scarcely available) extragalactic data, 12 C/ 13 C ratios appear to vary over a full order of magnitude, from >100 in ultraluminous high redshift galaxies to ∼100 in more local such galaxies to ∼40 in weaker starbursts that are not undergoing a large scale merger to 25 in the central molecular zone of the Milky Way. With 12 C being predominantly synthesized in massive stars, while 13 C is mostly ejected by longer lived lower mass stars at later times, this is qualitatively consistent with our results of decreasing carbon isotope ratios with time and rising metallicity. It is emphasized, however, that both infall of poorly processed material, initiating a nuclear starburst, and the ejecta from newly formed massive stars (in particular in the case of a top-heavy stellar initial mass function) can raise the carbon isotope ratio for a limited amount of time.

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“…1 listed above. SSC is the most luminous mid-IR source in the nucleus and is suggested to be a super star cluster (Keto et al 1999 Paglione et al 2004;García-Burillo et al 2000;Peng et al 1996). We put our main focus on these continuum and line peaks and describe their properties in the following.…”

Section: Overview Of the Central Molecular Zonementioning

confidence: 99%

Star-Forming Cloud Complexes in the Central Molecular Zone of NGC 253

Sakamoto

Mao

Matsushita

et al. 2011

ApJ

123

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We report 350 and 230 GHz observations of molecular gas and dust in the starburst nucleus of NGC 253 at 20-40 pc (1 -2 ) resolution. The data contain CO(3-2), HCN(4-3), CO(2-1), 13 CO(2-1), C 18 O(2-1), and continuum at 0.87 mm and 1.3 mm toward the central kiloparsec. The CO(2-1) size of the galaxy's central molecular zone (CMZ) is measured to be about 300 pc × 100 pc at the half-maximum of intensity. Five clumps of dense and warm gas stand out in the CMZ at arcsecond resolution, and they are associated with compact radio sources due to recent massive star formation. They contribute one-third of the CO emission in the central 300 pc and have 12 CO peak brightness temperatures around 50 K, molecular gas column densities on the order of 10 4 M pc −2 , gas masses on the order of 10 7 M in the size scale of 20 pc, volume-averaged gas densities of n H 2 ∼ 4000 cm −3 , and high HCN-to-CO ratios suggestive of higher fractions of dense gas than in the surrounding environment. It is suggested that these are natal molecular cloud complexes of massive star formation. The CMZ of NGC 253 is also compared with that of our Galaxy in CO(2-1) at the same 20 pc resolution. Their overall gas distributions are strikingly similar. The five molecular cloud complexes appear to be akin to such molecular complexes as Sgr A, Sgr B2, Sgr C, and the l = 1.• 3 cloud in the Galactic center. On the other hand, the starburst CMZ in NGC 253 has higher temperatures and higher surface (and presumably volume) densities than its non-starburst cousin.

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BIMA CS J=21 Observations of NGC 253: Kinematic Evidence for Dense Gas in a Bar

Cited by 56 publications

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First detections of extragalactic SO₂, NS and NO

First detections of extragalactic SO₂, NS and NO

Carbon and oxygen isotope ratios in starburst galaxies: New data from NGC 253 and Mrk 231 and their implications

Star-Forming Cloud Complexes in the Central Molecular Zone of NGC 253

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BIMA CS J=21 Observations of NGC 253: Kinematic Evidence for Dense Gas in a Bar

Cited by 56 publications

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First detections of extragalactic SO2, NS and NO

First detections of extragalactic SO2, NS and NO

Carbon and oxygen isotope ratios in starburst galaxies: New data from NGC 253 and Mrk 231 and their implications

Star-Forming Cloud Complexes in the Central Molecular Zone of NGC 253

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First detections of extragalactic SO₂, NS and NO

First detections of extragalactic SO₂, NS and NO