The Carina Nebula and Gum 31 molecular complex – II. The distribution of the atomic gas revealed in unprecedented detail

Rebolledo, David; Green, Anne; Burton, M. G.; Brooks, Kate; Breen, S. L.; Gaensler, B. M.; Contreras, Y.; Braiding, Catherine; Purcell, Cormac

doi:10.1093/mnras/stx2047

Cited by 18 publications

(27 citation statements)

References 31 publications

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“…Comparing HI 21cm to [C ii] and 12 CO 1-0, we find numerous bright CO clumps and bright [C ii] emission within the cavities in the Tr 14/Carina I region. In this part of the cavity, the cold HI in dense CO clumps may be the source of absorption, which was also discussed in Rebolledo et al (2017). On the other hand, we do not see significant CO emission in the cavity west of η Carinae, where the Keyhole nebula is located.…”

Section: Spatial Distribution Of Integrated [C Ii] Emissionsupporting

confidence: 71%

“…We find that there are cavities in the HI channel maps due to absorption features in the HI spectra as shown in Rebolledo et al (2017). Comparing the cavity to the [C ii] and CO emission, we find that the cavities have a strong correlation with CO and [C ii] in PPV space.…”

Section: Channel Maps Of [C Ii] 158 µM Co 1-0 Hi 21cm and H92αmentioning

confidence: 65%

“…To study the ISM structure, we select 6 positions representative of the HII region in the CNC, the ionization front of the large CO cloud to the west of Tr 14, and molecular regions ( Figure 4, numbers 1-6). We analyze the spectra including 13 CO 1-0, 12 CO 1-0 (Rebolledo et al 2016), [C ii] 158 µm, HI 21cm (Rebolledo et al 2017), H92α (Horiuchi et al 2012), and optical lines of nitrogen and hydrogen (Damiani et al 2016).…”

Section: Channel Maps Of [C Ii] 158 µM Co 1-0 Hi 21cm and H92αmentioning

confidence: 99%

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Probing ISM Structure in Trumpler 14 and Carina I Using the Stratospheric Terahertz Observatory 2

Seo

Goldsmith

Walker

et al. 2019

ApJ

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We present observations of the Trumpler 14/Carina I region carried out using the Stratospheric Terahertz Observatory 2 (STO2). The Trumpler 14/Carina I region is in the west part of the Carina Nebula Complex, which is one of the most extreme star-forming regions in the Milky Way. We observed Trumpler 14/Carina I in the 158 µm transition of [C ii] with a spatial resolution of 48 and a velocity resolution of 0.17 km s −1 . The observations cover a 0.25 • by 0.28 • area with central position l = 297.34 • , b = -0.60 • . The kinematics show that bright [C ii] structures are spatially and spectrally correlated with the surfaces of CO clouds, tracing the photodissociation region and ionization front of each molecular cloud. Along 7 lines of sight that traverse Tr 14 into the dark ridge to the southwest, we find that the [C ii] luminosity from the HII region is 3.7 times that from the PDR. In same los we find in the PDRs an average ratio of 1:4.1:5.6 for the mass in atomic gas:dark-CO gas: molecular gas traced by CO. Comparing multiple gas tracers including HI 21cm, [C ii], CO, and radio recombination lines, we find that the HII regions of the Carina Nebula Complex are well-described as HII regions with one-side freely expanding towards us, consistent with the champagne model of ionized gas evolution. The dispersal of the GMC in this region is dominated by EUV photoevaporation; the dispersal timescale is 20-30 Myr. Effective Resolution a 55 Pointing Accuracy <15 Spectral Resolution 1 MHz Velocity Resolution 0.17 km s −1 a Angular resolution of the regridded map.This study contains extensive analysis with many new findings. The followings are the highlights of this study and can be found in the discussion and conclusions sections. Comparing our [C ii] spectral map to the Mopra CO map, we found that bright [C ii] emission in the CNC is closely related to the CO clumps in position-position-velocity space, suggesting that bright [C ii] emission likely arises from PDR and ionization fronts. We also found large absorption cavities in HI 21 cm emission and that those cavities are in a good agreement with the CO clouds/clumps and the Keyhole Nebula, a CO-dark molecular cloud, in position-position space. On the other hand, velocities of the absorption cavities are ±5-10 km s −1 shifted from the CO velocity centroids, suggesting that the cavities may follow cold HI gas photoevaporating or stripped from cloud surfaces. Through detailed PDR modeling of 10 different regions representing various ISM structures, we found a mass proportion of 1:4.1:5.6 for the atomic:dark:molecular(CO) gas and that six out of ten regions are dominated by [C ii] emission from HII regions rather than PDRs. Finally, combining kinematics and modelings, we found that the three-dimensional morphology of the CNC is consistent with one side of numerous blister HII regions expanding freely toward us, similar to a champagne flow, with a lifetime of CO clouds exposed to HII regions being 20-30 Myr.We describe details of observations using STO2 and data reduction ...

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Section: Spatial Distribution Of Integrated [C Ii] Emissionsupporting

confidence: 71%

Section: Channel Maps Of [C Ii] 158 µM Co 1-0 Hi 21cm and H92αmentioning

confidence: 65%

Section: Channel Maps Of [C Ii] 158 µM Co 1-0 Hi 21cm and H92αmentioning

confidence: 99%

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Probing ISM Structure in Trumpler 14 and Carina I Using the Stratospheric Terahertz Observatory 2

Seo

Goldsmith

Walker

et al. 2019

ApJ

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“…In the second paper of the project, we reported high sensitivity and high resolution maps of the H I 21-cm line towards the CNC obtained with the ATCA (Rebolledo et al 2017). This detailed map of the atomic gas revealed a complex filamentary structure across the velocity range that crosses the Galactic disk.…”

Section: Introductionmentioning

confidence: 95%

Effect of Feedback of Massive Stars in the Fragmentation, Distribution, and Kinematics of the Gas in Two Star-forming Regions in the Carina Nebula

Rebolledo

Guzmán

Contreras

et al. 2020

ApJ

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We present ALMA high spatial resolution observations towards two star forming regions located in one of the most extreme zones of star formation in the Galaxy, the Carina Nebula. One region is located at the center of the nebula and is severally affected by the stellar feedback from high-mass stars, while the other region is located further south and is less disturbed by the massive star clusters. We found that the region at the center of the nebula is forming less but more massive cores than the region located in the south, suggesting that the level of stellar feedback effectively influence the fragmentation process in clumps. Lines such as HCN HCO + and SiO show abundant and complex gas distributions in both regions, confirming the presence of ionization and shock fronts. Jeans analysis suggests that the observed core masses in the region less affected by the massive stars are consistent with thermal fragmentation, but turbulent Jeans fragmentation might explain the high masses of the cores identified in the region in the center of Carina. Consistently, two different analyses in the HCO + line provided evidence for a higher level of turbulence in the gas more affected by the stellar feedback. The gas column density probability functions, N-PDFs, show log-normal shapes with clear transitions to power law regimes. We observed a wider N-PDF in the region at the center of the nebula, which provides further evidence for a higher level of turbulence in the material with a higher level of massive stellar feedback.

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“…Burkhart et al (2015b) and Imara & Burkhart (2016) studied nearby molecular clouds and report H i N-PDFs with a log-normal shape, without any power-law tail. Rebolledo et al (2017) studied the Carina and Gum 31 molecular complex, where the H i N-PDF also shows a log-normal shape.…”

Section: Introductionmentioning

confidence: 99%

Cloud formation in the atomic and molecular phase: H I self absorption (HISA) towards a giant molecular filament

Wang

Bihr

Beuther

et al. 2020

A&A

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Molecular clouds form from the atomic phase of the interstellar medium. However, characterizing the transition between the atomic and the molecular interstellar medium (ISM) is a difficult observational task. Here we address cloud formation processes by combining H i self absorption (HISA) with molecular line data. Column density probability density functions (N-PDFs) are a common tool to examine molecular clouds. One scenario proposed by numerical simulations is that the N-PDF evolves from a log-normal shape at early times to a power-law-like shape at later times. To date, investigations of N-PDFs are mostly limited to the molecular component of the cloud. In this paper, we study the cold atomic component of the giant molecular filament GMF38.1-32.4a (GMF38a, distance=3.4 kpc, length∼ 230 pc), calculate its N-PDFs and study its kinematics. We identify an extended HISA feature, which is partly correlated with the 13 CO emission. The peak velocities of the HISA and 13 CO observations agree well on the eastern side of the filament, whereas a velocity offset of approximately 4 km s −1 is found on the western side. The sonic Mach number we derive from the linewidth measurements shows that a large fraction of the HISA, which is ascribed to the cold neutral medium (CNM), is at subsonic and transonic velocities. The column density of the CNM part is on the order of 10 20 to 10 21 cm −2 . The column density of molecular hydrogen, traced by 13 CO, is an order of magnitude higher. The N-PDFs from HISA (CNM), H i emission (the warm and cold neutral medium), and 13 CO (molecular component) are well described by log-normal functions, which is in agreement with turbulent motions being the main driver of cloud dynamics. The N-PDF of the molecular component also shows a power law in the high column-density region, indicating self-gravity. We suggest that we are witnessing two different evolutionary stages within the filament. The eastern subregion seems to be forming a molecular cloud out of the atomic gas, whereas the western subregion already shows high column density peaks, active star formation and evidence of related feedback processes.

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The Carina Nebula and Gum 31 molecular complex – II. The distribution of the atomic gas revealed in unprecedented detail

Cited by 18 publications

References 31 publications

Probing ISM Structure in Trumpler 14 and Carina I Using the Stratospheric Terahertz Observatory 2

Probing ISM Structure in Trumpler 14 and Carina I Using the Stratospheric Terahertz Observatory 2

Effect of Feedback of Massive Stars in the Fragmentation, Distribution, and Kinematics of the Gas in Two Star-forming Regions in the Carina Nebula

Cloud formation in the atomic and molecular phase: H I self absorption (HISA) towards a giant molecular filament

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The Carina Nebula and Gum 31 molecular complex – II. The distribution of the atomic gas revealed in unprecedented detail

Cited by 18 publications

References 31 publications

Probing ISM Structure in Trumpler 14 and Carina I Using the Stratospheric Terahertz Observatory 2

Probing ISM Structure in Trumpler 14 and Carina I Using the Stratospheric Terahertz Observatory 2

Effect of Feedback of Massive Stars in the Fragmentation, Distribution, and Kinematics of the Gas in Two Star-forming Regions in the Carina Nebula

Cloud formation in the atomic and molecular phase: H I self absorption (HISA) towards a giant molecular filament

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Cloud formation in the atomic and molecular phase: H I self absorption (HISA) towards a giant molecular filament