[C II] 158<i>μ</i>m and [N II] 205<i>μ</i>m emission from IC 342

Röllig, M.; Simon, R.; Güsten, R.; Stutzki, J.; Israel, F. P.; Jacobs, K.

doi:10.1051/0004-6361/201526267

Cited by 20 publications

(27 citation statements)

References 37 publications

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“…The finding of a "normal" ratio of 20-40 is therefore surprising and needs to be interpreted carefully. Röllig et al (2016) found a [Cii]/[Nii] luminosity ratio of 12 in the central regions of IC 342, a normal local star-forming galaxy, similar to our own Milky Way, suggesting that a majority of the [Cii] emission originates in ionized gas. However, Lu et al (2015) find a positive correlation between the [Cii]/[Nii] ratio and bluer FIRcolor in local galaxies.…”

Section: Analysis Of the Individual Sourcessupporting

confidence: 71%

ALMA REVEALS WEAK [N ii] EMISSION IN “TYPICAL” GALAXIES AND INTENSE STARBURSTS AT z = 5–6

Pavesi

Riechers

Capak

et al. 2016

ApJ

132

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We report interferometric measurements of [Nii] 205 µm fine-structure line emission from a representative sample of three galaxies at z = 5-6 using the Atacama Large (sub)Millimeter Array (ALMA). These galaxies were previously detected in [Cii] and far-infrared continuum emission and span almost two orders of magnitude in star formation rate (SFR). Our results show at least two different regimes of ionized inter-stellar medium properties for galaxies in the first billion years of cosmic time, separated by theirUV star-forming galaxy, likely directly or indirectly (by its effect on the radiation field) related to low dust abundance and low metallicity. The infrared-luminous modestly star-forming Lyman Break Galaxy (LBG) in our sample is characterized by an ionized-gas fraction (L [CII] /L [NII] 20) typical of local star-forming galaxies and shows evidence for spatial variations in its ionized-gas fraction across an extended gas reservoir. The extreme SFR, warm and compact dusty starburst AzTEC-3 shows an ionized fraction higher than expected given its star-formation rate surface densitydominantly traces a diffuse ionized medium rather than star-forming Hii regions in this type of galaxy. This highest redshift sample of [Nii] detections provides some of the first constraints on ionized and neutral gas modeling attempts and on the structure of the inter-stellar medium at z = 5-6 in "normal" galaxies and starbursts.

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Section: Analysis Of the Individual Sourcessupporting

confidence: 71%

ALMA REVEALS WEAK [N ii] EMISSION IN “TYPICAL” GALAXIES AND INTENSE STARBURSTS AT z = 5–6

Pavesi

Riechers

Capak

et al. 2016

ApJ

132

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“…The c(n e ,T e ) coefficients are scaling factors between I([NII]) and N(N + ) as a function of the adopted n e and T e , that take into account the relative population of the three fine-structure levels of the nitrogen ion ( 3 P 0 , 3 P 1 , and 3 P 2 ) due to collisions with electrons and spontaneous decay. They are calculated for the [NII] 205 µm and 122 µm transitions in Röllig et al (2016). These coefficients are almost constant for 5000 K < T e < 8000 K and vary around 15% for 100 cm −3 < n e < 500 cm −3 (Röllig et al 2016), which are the relevant ranges for the gas physical conditions in the AF region and for the observed [NII] line transition at 205 µm used in this work.…”

Section: [C/n] Elemental Abundance Ratio In the Afmentioning

confidence: 94%

“…Following Röllig et al (2016), under the assumption of local thermodynamic equilibrium (LTE) and optically thin [NII] emission (Goldsmith et al 2015), the ionized nitrogen column density N(N + ) for any given radial velocity component in Table 4 is derived as…”

Section: [C/n] Elemental Abundance Ratio In the Afmentioning

confidence: 99%

Warm ISM in the Sgr A Complex. II. The [C/N] abundance ratio traced by [CII] 158 um and [NII] 205 um observations toward the Arched Filaments at the Galactic center

García,

Abel,

Röllig

et al. 2021

Preprint

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Context. The Arches Cluster -Arched Filaments (AF) system is our Galaxy's prime example of the complexity involved in the interaction between the strong radiation field of numerous OB stars and their surrounding ISM in extremely harsh environments such as the Galactic center (GC) of the Milky Way. It offers a unique opportunity to study the close relationship between photon-dominated regions (PDRs) and H II regions and their relative contributions to the observed [CII] emission.Aims. We aim to investigate the I([CII]) versus I([NII]) integrated intensity behavior in the AF region in order to assess the [CII] emission contribution from the H II region, which is traced by [NII] line observations, and PDR components in the highmetallicity environment of the GC. Methods. We used [CII] 158 µm and [NII] 205 µm fine structure line observations of the AF in the literature to compare their observational integrated intensity distribution to semi-theoretical predictions for the contribution of H II regions and adjacent PDRs to the observed [CII] emission. We explored variations in the [C/N] elemental abundance ratio to explain the overall behavior of the observed relationship. Based on our models, the H II region and PDR contributions to the observed [CII] emission is calculated for a few positions within and near to the AF. Estimates for the [C/N] abundance ratio and [N/H] nitrogen elemental abundance in the AF can then be derived. Results. The behavior of the I([CII]) versus I([NII]) relationship in the AF can be explained by model results satisfying 0.84 < [C/N] AF < 1.41, with model metallicities ranging from 1 Z ⊙ to 2 Z ⊙ , hydrogen volume density log n(H) = 3.5, and ionization parameters log U from −1 to −2. A least-squares fit to the model data points yields log I([CII]) = 1.068× log I([NII]) + 0.645 to predict the [CII]emission arising from the H II regions in the AF. The fraction of the total observed [CII] emission arising from within PDRs varies between ∼ 0.20 and ∼ 0.75. Our results yield average values for the carbon-to-nitrogen ratio and nitrogen elemental abundances of [C/N] AF = 1.13 ± 0.09 and [N/H] AF = 6.21×10 −4 for the AF, respectively. They are a factor of ∼ 0.4 smaller and ∼ 7.5 larger than their corresponding Galactic disk values. Conclusions. The large spatial variation of the fraction of [CII] emission arising either from H II regions or PDRs suggests that both contributions must be disentangled before any modeling attempt is made to explain the observed [CII] emission in the AF. We suggest that secondary production of nitrogen from low-to intermediate-mass stars in the Galactic bulge is a plausible mechanism to explain the large abundance differences between the GC and the Galactic disk. The mass loss of such stars would enrich the GC ISM with nitrogen as the gas falls into the inner GC orbits where the AF are located. Overall, our results show that tight constraints are needed on the [C/N] abundance ratio for the GC, significantly tighter than previous abundance measurements have discerned.

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“…This variation on 20 ′′ scale is not surprising considering that the 7-pixel footprint of upGREAT covers ∼2.3 pc across, and probably includes a number of different cloud components. Only for the central pixel (pix 1) do both [C ii] (Röllig et al 2016). The rms noise for T mb (K) in the calibrated spectra shown in Figure 5 are in the range of 0.05 to 0.17 K for [N ii], 0.04 to 0.25 K for [C ii] averaged over 7 pixels, and 0.08 to 0.30 K in pixel #1.…”

Section: Observationsmentioning

confidence: 99%

“…Unfortunately the crowding of features along the LOS to the Scutum tangency, as seen in Figures 2 and 5, makes it difficult to correct for the [C ii] absorption using the approach described by Langer et al (2016). The large fraction of [C ii] arising from [N ii] regions is not just a phenomenon in the Galactic plane as Röllig et al (2016) …”

Section: High Density Ionized Gas In the Scutum Molecular Layermentioning

confidence: 99%

Ionized gas in the Scutum spiral arm as traced in [N ii] and [C ii]

Langer

Velusamy

Goldsmith

et al. 2017

A&A

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Context. The warm ionized medium (WIM) occupies a significant fraction of the Galactic disk. Determining the WIM properties at the leading edge of spiral arms is important for understanding its dynamics and cloud formation. Aims. To derive the properties of the WIM at the inner edge of the Scutum arm tangency, which is a unique location in which to disentangle the WIM from other components, using the ionized gas tracers C + and N + . Methods. We use high spectral resolution [C ii] 158 µm and [N ii] 205 µm fine structure line observations taken with the upGREAT and GREAT instruments, respectively, on SOFIA, along with auxiliary H i and 13 CO observations. The observations consist of samples in and out of the Galactic plane along 18 lines of sight (LOS) between longitude 30• and 32• . Results. We detect strong [N ii] emission throughout the Scutum tangency. At V LS R = 110 to 125 km s −1 where there is little, if any, 13 CO, we are able to disentangle the [N ii] and [C ii] emission that arises from the WIM at the arm's inner edge. We find an average electron density ∼0.9 cm −3 in the plane, and ∼0.4 cm −3 just above the plane. The [N ii] emission decreases exponentially with latitude with a scale height ∼55 pc. For V LS R <110 km s −1 there is [N ii] emission tracing highly ionized gas throughout the arm's molecular layer. This ionized gas has a high density, n(e) ∼30 cm −3 , and a few percent filling factor. We also find evidence for [C ii] absorption by foreground gas. Conclusions. [N ii] and [C ii]observations at the Scutum arm tangency reveal a highly ionized gas with average electron density about 10 to 20 times those of the interarm WIM, and is best explained by a model in which the interarm WIM is compressed as it falls into the potential well of the arm. The widespread distribution of [N ii] in the molecular layers shows that high density ionized gas is distributed throughout the Scutum arm. The electron densities derived from [N ii] for these molecular cloud regions are ∼30 cm −3 , and probably arise in the ionized boundary layers of clouds. The [N ii] detected in the molecular portion of the spiral arm arises from several cloud components with a combined total depth ∼8 pc. This [N ii] emission most likely arises from ionized boundary layers, probably the result of the shock compression of the WIM as it impacts the arm's neutral gas, as well as from extended H ii regions.

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[C II] 158μm and [N II] 205μm emission from IC 342

Cited by 20 publications

References 37 publications

ALMA REVEALS WEAK [N ii] EMISSION IN “TYPICAL” GALAXIES AND INTENSE STARBURSTS AT z = 5–6

ALMA REVEALS WEAK [N ii] EMISSION IN “TYPICAL” GALAXIES AND INTENSE STARBURSTS AT z = 5–6

Warm ISM in the Sgr A Complex. II. The [C/N] abundance ratio traced by [CII] 158 um and [NII] 205 um observations toward the Arched Filaments at the Galactic center

Ionized gas in the Scutum spiral arm as traced in [N ii] and [C ii]

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