Neutral hydrogen absorption at the centre of NGC 2146

Tarchi, A.; Greve, A.; Peck, A. B.; Neininger, N.; Wills, K. A.; Pedlar, A.; Klein, U.

doi:10.1111/j.1365-2966.2004.07792.x

Cited by 13 publications

(12 citation statements)

References 23 publications

(41 reference statements)

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“…Finally, the radial velocities derived from H i absorption-line measurements within the central ±1.5 kpc (Tarchi et al 2004) agree with our and BCD-75's Hα line data and the CO line data, shown in Fig. 10.…”

Section: The Central Region Radial Velocities (R ≤ 4 Kpc)supporting

confidence: 86%

NGC 2146's starburst region and extended structure

Greve¹,

Neininger

Sievers

et al. 2006

A&A

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We present mm-wavelength and optical observations of the starburst region in NGC 2146. This region of ∼4 kpc diameter contains a well-ordered distribution of stars, gas, and dust, and a well-ordered rotation. The possible anomalies found in our observation are a warped CO distribution and an increase in the CO line width at the NW edge of the starburst region. The investigation of a possible encounter or merger origin of the starburst may therefore have to concentrate on the distorted outer structure of the galaxy. There are three large-scale features of ∼20 kpc extent, two of which give the impression of being stellar sub-systems. The third feature is an incomplete and expanding ring of H ii regions and stars, apparently indicating an event that occurred some 300 Myr ago.

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Section: The Central Region Radial Velocities (R ≤ 4 Kpc)supporting

confidence: 86%

NGC 2146's starburst region and extended structure

Greve¹,

Neininger

Sievers

et al. 2006

A&A

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“…T peak background continuum source and that only the ground state of the molecule is populated, the total column density of the absorbing HDO/H 18 2 O can then be computed from (Comito et al 2003;Tarchi et al 2004)…”

Section: Freqmentioning

confidence: 99%

Water deuterium fractionation in the high-mass hot core G34.26+0.15

Liu

Parise

Wyrowski

et al. 2013

A&A

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Context. Water is an essential molecule in oxygen chemistry and the main constituent of grain icy mantles. The formation of water can be studied through the HDO/H 2 O ratio. Thanks to the launch of the Herschel satellite and the advance of sensitive submillimeter receivers on ground telescopes, many H 2 O and HDO transitions can now be observed, enabling more accurate studies of the level of water fractionation. Aims. Using these new technologies, we aim at revisiting the water fractionation studies toward massive star-forming regions. We present here a detailed study toward G34.26+0.15, a massive star-forming region associated with compact HII regions. Methods. We present observations of five HDO lines obtained with the APEX telescope. Two of those transitions are ground-state transitions. Two of the three high-excitation lines were additionally observed at higher angular resolution with the SMA. We analyzed these observations using the 1D radiative transfer code RATRAN and adopting different physical profiles from two different models. Results. Although the inner and outer fractional abundances relative to H 2 can be best constrained to be X HDO in (T > 100 K) = (5−7) × 10 −8 (3σ) and X HDO out (T ≤ 100 K) = (0.3−2) × 10 −11 (3σ), the line profile of the 893 GHz ground transition cannot be well reproduced. This line profile is shown to be very sensitive to the velocity field. To better constrain the velocity field, it is necessary to observe the HDO line at 893 GHz with high angular resolution. The H 2 O abundance is deduced from one high-excitation and one ground transition H 18 2 O line. The D/H ratios of water are 3.0 × 10 −4 in the inner region and (1.9−4.9) × 10 −4 in the outer region of the core. The HDO fractional abundance in the inner and outer regions are different by more than four orders, which implies that the sublimation is very similar in low-and high-mass protostars. The D/H ratios of water in G34.26 + 0.15 are close to the value obtained for the same source in a previous study, and similar to those in other high-mass sources, but lower than those in low-mass protostars, suggesting the possibility that the dense and cold pre-collapse phase is shorter for high-mass star-forming regions.

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“…This bright core measures several kiloparsecs in diameter, and is a strong source of radio emission (1.4 GHz flux density ≈1 Jy, see de Bruyn 1977;Condon et al 1996;Braun et al 2007) against which HI is seen in absorption (Taramopoulos et al 2001;Tarchi et al 2004). Taramopoulos et al (2001) have presented a VLA HI map including short spacings that shows a neutral gas filament extending from the main body of galactic HI to the south over half a degree (160 kpc), as well as a large amount of gas extending out of the galaxy to the north.…”

Section: Ngc 2146mentioning

confidence: 99%

“…However, the multi-transition observations of 12 CO and 13 CO presented here allow us to characterize the overall physical condition of the central molecular gas in ways that arer not possible otherwise. Kaneko et al (1989), Tarchi et al (2004), Young et al (1988b), Irwin & Seaquist (1991), García-Burillo et al (2003), Beswick et al (2002), Meixner et al (1990), Davies et al (2004); c see Moustakas et al (2006).…”

Section: Introductionmentioning

confidence: 99%

CI and CO in nearby galaxy centers

Israel¹

2008

A&A

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Aims. We study the physical properties and amount of molecular gas in the central regions of galaxies with active nuclei. Methods. Maps and measurements of the J = 1−0, J = 2−1, J = 3−2, J = 4−3 12 CO, the J = 1−0, J = 2−1, and J = 3−2 13 CO lines in the central arcminute squared of NGC 1068, NGC 2146, NGC 3079, NGC 4826, and NGC 7469, as well as 492 GHz CI maps in three of these are used to model the molecular gas clouds in these galaxies. Results. Bright CO concentrations were detected and mapped in all five objects. In all cases, the observed lines could be fitted with two distinct gas components. The physical condition of the molecular gas is found to differ from galaxy to galaxy. Rather high kinetic temperatures of 125−150 K occur in NGC 2146 and NGC 3079. Very high densities of 0.3−1.0 × 10 5 cm −3 occur in NGC 2146, NGC 3079, and NGC 7469. The CO to H 2 conversion factor X is typically an order of magnitude less than the "standard" value in the solar neighborhood. The molecular gas is constrained within radii between 0.9 and 1.5 kpc from the nuclei. Within these radii, H 2 masses are typically 1.2−2.5 × 10 8 M . The exception is the (relatively nearby) merger NGC 4826 with R = 0.3 kpc, and M = 3 × 10 7 M . The H 2 mass is typically about one per cent of the dynamical mass in the same region.

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Neutral hydrogen absorption at the centre of NGC 2146

Cited by 13 publications

References 23 publications

NGC 2146's starburst region and extended structure

NGC 2146's starburst region and extended structure

Water deuterium fractionation in the high-mass hot core G34.26+0.15

CI and CO in nearby galaxy centers

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