ALMA Observations of Atomic Carbon [C i] (3P1 → 3P0) and Low-J CO Lines in the Starburst Galaxy NGC 1808

Salak, Dragan; Nakai, Naomasa; Seta, Masumichi; Miyamoto, Yusuke

doi:10.3847/1538-4357/ab55dc

Cited by 33 publications

(23 citation statements)

References 89 publications

(149 reference statements)

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“…We smoothed our 350 GHz continuum map at the same resolution and the integrated flux in a 2 diameter region is 27.8 mJy. The continuum at 500 GHz observed with ALMA in Band 8 at 0.825 × 0.59 resolution is presented by Salak et al (2019). At the AGN position, the continuum peaks at 54 mJy and smoothing our 350 GHz continuum at the same resolution of the 500 GHz map, we derive a spectral index of α = 3.6.…”

Section: Continuum Emissionmentioning

confidence: 96%

“…As shown in the previous section, with the CO(3−2) velocity field, we can see a tilt in the kinematic major axis towards the nucleus. ALMA observations of neutral atomic carbon, [CI], presented in Salak et al (2019) at a spatial resolution of 0.82 × 0.6 , show a remarkable resemblance to the CO(3−2) morphology and kinematics. They also reveal this tilted kinematics in the center.…”

Section: Kinematic Misalignment At the Center Of The Nuclear Spiralmentioning

confidence: 99%

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Black hole feeding and star formation in NGC 1808

Audibert

Combes

García‐Burillo

et al. 2021

A&A

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We report on Atacama Large Millimeter Array (ALMA) observations of CO(3−2) emission in the Seyfert2/starburst galaxy NGC 1808, at a spatial resolution of 4 pc. Our aim is to investigate the morphology and dynamics of the gas inside the central 0.5 kpc and to probe the nuclear feeding and feedback phenomena. We discovered a nuclear spiral of radius 1″ = 45 pc. Within it, we found a decoupled circumnuclear disk or molecular torus of a radius of 0.13″ = 6 pc. The HCN(4−3) and HCO+(4−3) and CS(7−6) dense gas line tracers were simultaneously mapped and detected in the nuclear spiral and they present the same misalignment in the molecular torus. At the nucleus, the HCN/HCO+ and HCN/CS ratios indicate the presence of an active galactic nucleus (AGN). The molecular gas shows regular rotation, within a radius of 400 pc, except for the misaligned disk inside the nuclear spiral arms. The computations of the torques exerted on the gas by the barred stellar potential reveal that the gas within a radius of 100 pc is feeding the nucleus on a timescale of five rotations or on an average timescale of ∼60 Myr. Some non-circular motions are observed towards the center, corresponding to the nuclear spiral arms. We cannot rule out that small extra kinematic perturbations could be interpreted as a weak outflow attributed to AGN feedback. The molecular outflow detected at ≥250 pc in the NE direction is likely due to supernovae feedback and it is connected to the kpc-scale superwind.

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Section: Continuum Emissionmentioning

confidence: 96%

Section: Kinematic Misalignment At the Center Of The Nuclear Spiralmentioning

confidence: 99%

Black hole feeding and star formation in NGC 1808

Audibert

Combes

García‐Burillo

et al. 2021

A&A

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“…Jiao et al (2019) found that the [C I] (1-0) luminosity correlates linearly with the CO (1-0) luminosity for the different types of galaxies (see also Jiao et al 2017). However, recent studies claim that caution is needed when the [C I] (1-0) line is used as a tracer of molecular gas mass in resolved galaxies because the physical conditions strongly affect the intensities (e.g., Salak et al 2019;Saito et al 2020;Miyamoto et al 2021). It is also predicted that the relative abundance of C I is enhanced in outflows and cosmic-ray (CR) dominated regions by destroying CO (Bialy & Sternberg 2015;Bisbas et al 2015;Papadopoulos et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Spatially-resolved relation between [CI] $^{3}P_{1}$-$^{3}P_{0}$ and $^{12}$CO (1-0) in Arp 220

Ueda,

Michiyama,

Iono

et al. 2022

Preprint

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We present ∼0. ′′ 3 (114 pc) resolution maps of [C I] 3 P 1 -3 P 0 (hereafter [C I] (1-0)) and 12 CO (1-0) obtained toward Arp 220 with the Atacama Large Millimeter/submillimeter Array. The overall distribution of the [C I] (1-0) emission is consistent with the CO (1-0). While the [C I] (1-0) and CO (1-0) luminosities of the system follow the empirical linear relation for the unresolved ULIRG sample, we find a sublinear relation between [C I] (1-0) and CO (1-0) using the spatially-resolved data. We measure the [C I] (1-0)/CO (1-0) luminosity ratio per pixel in star-forming environments of Arp 220 and investigate its dependence on the CO (3-2)/CO (1-0) ratio (R CO ). On average, the [C I] (1-0)/CO (1-0) luminosity ratio is almost constant up to R CO ≃ 1 and then increases with R CO . According to the radiative transfer analysis, a high C I/CO abundance ratio is required in regions with high [C I] (1-0)/CO (1-0) luminosity ratios and R CO > 1, suggesting that the C I/CO abundance ratio varies at ∼100 pc scale in Arp 220. The [C I] (1-0)/CO (1-0) luminosity ratio depends on multiple factors and may not be straightforward to interpret. We also find the high-velocity components traced by [C I] (1-0) in the western nucleus, likely associated with the molecular outflow. The [C I] (1-0)/CO (1-0) luminosity ratio in the putative outflow is 0.87 ± 0.28, which is four times higher than the average ratio of Arp 220. While there is a possibility that the [C I] (1-0) and CO (1-0) emission traces different components, we suggest that the high line ratios are likely because of elevated C I/CO abundance ratios based on our radiative transfer analysis. A C I-rich and CO-poor gas phase in outflows could be caused by the irradiation of the cosmic rays, the shock heating, and the intense radiation field.

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“…Fine structure lines of atomic carbon, for example [C ], are an additional tracer to probe the cold molecular phase (e.g., Papadopoulos & Greve 2004;Valentino et al 2018). Observational studies in the local Universe have shown that CO and [C ] can coexist, suggesting that both transitions arise from the same regions (e.g., White et al 1994;Ikeda et al 2002;Israel & Baas 2002), though spatial variations could be present (e.g., Salak et al 2019). Analysis using simultaneously [C ] and multi-transition CO observations at high redshifts found agreement between the H 2 masses determined through the two different tracers (e.g., Weiß et al 2003;Alaghband-Zadeh et al 2013), corroborating the assumption that [C ] and CO usually coexist (Carilli & Walter 2013).…”

Section: Introductionmentioning

confidence: 99%

APEX at the QSO MUSEUM: molecular gas reservoirs associated with $z\sim$3 quasars and their link to the extended Ly$α$ emission

Muñoz-Elgueta,

Battaia,

Kauffmann

et al. 2022

Preprint

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Cool gas (T∼10 4 K) traced by hydrogen Ly𝛼 emission is now routinely detected around 𝑧 ∼ 3 quasars, but little is known about their molecular gas reservoirs. Here, we present an APEX spectroscopic survey of the CO(6-5), CO(7-6) and [C ](2-1) emission lines for 9 quasars from the QSO MUSEUM survey which have similar UV luminosities, but very diverse Ly𝛼 nebulae. These observations ( rms = 2.6 mJy in 300 km s −1 ) detected three CO(6-5) lines with 3.4≤ 𝐼 CO(6−5) ≤5.1 Jy km s −1 , 620≤FWHM≤707 km s −1 , and three [C ](2-1) lines with 2.3≤ 𝐼 [C ] (2−1) ≤15.7 Jy km s −1 , 329≤FWHM≤943 km s −1 . For the CO and [C ] detected sources, we constrain the molecular gas reservoirs to be M H 2 = (0.4−6.9) ×10 11 M , while the non-detections imply M H 2 < 1.1 × 10 11 M . We compare our observations with the extended Ly𝛼 properties to understand the link between the cool and the molecular gas phases. We find large velocity shifts between the bulk of Ly𝛼 and the molecular gas systemic redshift in five sources (from ∼-400 to ∼ +1200 km s −1 ). The sources with the largest shifts have the largest Ly𝛼 line widths in the sample, suggesting more turbulent gas conditions and/or large-scale inflows/outflows around these quasars. We also find that the brightest (𝐼 [C ] (2−1) = 15.7 ± 3.7 Jy km s −1 ) and the widest (FWHM∼900 km s −1 ) lines are detected for the smallest and dimmest Ly𝛼 nebulae. From this, we speculate that host galaxy obscuration can play an important role in reducing the ionizing and Ly𝛼 photons able to escape to halo scales, and/or that these systems are hosted by more massive halos.

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ALMA Observations of Atomic Carbon [C i] (³P₁ → ³P₀) and Low-J CO Lines in the Starburst Galaxy NGC 1808

Cited by 33 publications

References 89 publications

Black hole feeding and star formation in NGC 1808

Black hole feeding and star formation in NGC 1808

Spatially-resolved relation between [CI] $^{3}P_{1}$-$^{3}P_{0}$ and $^{12}$CO (1-0) in Arp 220

APEX at the QSO MUSEUM: molecular gas reservoirs associated with $z\sim$3 quasars and their link to the extended Ly$α$ emission

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