A<i>Herschel</i>[C II] Galactic plane survey

Pineda, J. L.; Langer, W. D.; Goldsmith, Paul F.

doi:10.1051/0004-6361/201424054

Cited by 115 publications

(145 citation statements)

References 82 publications

(143 reference statements)

Supporting

Mentioning

138

Contrasting

Order By: Relevance

“…Such observations have shown that while XF can be more or less spatially constant in some cases, like in the disk of our Galaxy and other external galaxies (see Sandstrom et al 2013;Planck Collaboration 2011a), there can be regions of "dark" gas, H2 with no CO emission, both in our Galaxy and other galaxies (e.g., see Planck Collaboration 2011a; Baes et al 2014;Clark et al 2012;Pineda et al 2014;Roman-Duval et al 2010;Saintonge et al 2012;Smith et al 2014). Therefore, observations of dust continuum emission provide a vital check on results inferred from CO J = 1 → 0 observations.…”

Section: Introductionmentioning

confidence: 84%

Continuum observations of M 51 and M 83 at 1.1 mm with AzTEC

Wall

Puerari

Tilanus

et al. 2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

We observed the spiral galaxies M 51 and M 83 at 20" spatial resolution with the bolometer array AzTEC on the JCMT in the 1.1 mm continuum, recovering the extended emission out to galactocentric radii of more than 12 kpc in both galaxies. The 1.1 mm-continuum fluxes are 5.6±0.7 and 9.9±1.4 Jy, with associated gas masses estimated at 9.4 × 10 9 M and 7.2 × 10 9 M for M 51 and M 83, respectively. In the interarm regions of both galaxies the N(H 2 )/I(CO) (or X-factor) ratios exceed those in the arms by factors of ∼ 1.5-2. In the inner disks of both galaxies, the X-factor is about 1 × 10 20 cm −2 · (K · km · s −1 ) −1 . In the outer parts, the CO-dark molecular gas becomes more important.While the spiral density wave in M 51 appears to influence the interstellar medium and stars in a similar way, the bar potential in M 83 influences the interstellar medium and the stars differently. We confirm the result of Foyle et al. (2010) that the arms merely heighten the star formation rate and the gas surface density in the same proportion. Our maps reveal a threshold gas surface density for an SFR increase by two or more orders of magnitude. In both galaxy centers, the molecular gas depletion time is about 1 Gyr climbing to 10-20 Gyr at radii of 6-8 kpc. This is consistent with an inside-out depletion of the molecular gas in the disks of spiral galaxies.

show abstract

Section: Introductionmentioning

confidence: 84%

Continuum observations of M 51 and M 83 at 1.1 mm with AzTEC

Wall

Puerari

Tilanus

et al. 2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

show abstract

“…Based on numerical models of photo-ionization gas and PDRs using the Cloudy model (Ferland et al 2013), Abel (2006) presented the following correlation, This is a much higher fraction than the often assumed range of 10−60% (Abel 2006). Pineda et al (2014) estimate that in the Milky way the contribution from different gas phases to the [C II] luminosity is dense PDRs (30%), cold HI (25%), CO-dark H 2 (25%), and ionized gas (20%). These are averaged values.…”

Section: [N Ii] and [C Ii] Analysismentioning

confidence: 99%

“…On global scales, [C II] emission from H II regions only contributes about 20% to the total [C II] intensity (Pineda et al 2014), but an increased active star formation gives rise to a higher FUV flux on larger scales and to an enhanced [C II]/CO line ratio accordingly. The much higher angular resolution of the SOFIA [C II] data compared to the data available to Stacey et al (1991) reveals significant local variations in the line ratio when pointing on or off sites of active star formation.…”

Section: The [C Ii] To 12 Co (1−0) Ratiomentioning

confidence: 99%

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

Röllig

Simon

Güsten

et al. 2016

A&A

View full text Add to dashboard Cite

Context. Atomic fine-structure line emission is a major cooling process in the interstellar medium (ISM). In particular the [C II] 158 µm line is one of the dominant cooling lines in photon-dominated regions (PDRs). However, it is not confined to PDRs but can also originate from the ionized gas closely surrounding young massive stars. observed with the GREAT receiver on board SOFIA.We present different methods to utilize the superior spatial and spectral resolution of our new data to infer information on how the gas kinematics in the nuclear region influence the observed line profiles. In particular we present a super-resolution method to derive how unresolved, kinematically correlated structures in the beam contribute to the observed line shapes. Results. We find that the emission coming from the ionized gas shows a kinematic component in addition to the general Doppler signature of the molecular gas. We interpret this as the signature of two bi-polar lobes of ionized gas expanding out of the galactic plane. We then show how this requires an adaptation of our understanding of the geometrical structure of the nucleus of IC 342. Examining the starburst activity we find ratios I([C II])/I( 12 CO(1−0)) between 400 and 1800 in energy units. Applying predictions from numerical models of H II and PDR regions to derive the contribution from the ionized phase to the total [C II] emission we find that 35−90% of the observed [C II] intensity stems from the ionized gas if both phases contribute. Averaged over the central few hundred parsec we find for the [C II] contribution a H II-to-PDR ratio of 70:30. Conclusions. The ionized gas in the center of IC 342 contributes more strongly to the overall [C II] emission than is commonly observed on larger scales and than is predicted. Kinematic analysis shows that the majority of the [C II] emission is related to the strong but embedded star formation in the nuclear molecular ring and only marginally emitted from the expanding bi-polar lobes of ionized gas.

show abstract

“…The fine structure line of ionized carbon, [C ii], at 158 μm is widely used to trace the galactic star formation rate (SFR; Stacey et al 2010;de Looze et al 2011de Looze et al , 2014Pineda et al 2014), as is the far-infrared (FIR) dust emission (e.g. Malhotra et al 1997;Luhman et al 1998;Stacey et al 2010;de Looze et al 2014).…”

Section: Introductionmentioning

confidence: 99%

“…However there are some notable exceptions in which the luminosity of [C ii] is significantly suppressed with respect to the infrared luminosity. The relationship between the intensity of [C ii] and other star formation tracers appears to work in the Galactic disk (Pineda et al 2014) and most extragalactic sources (de Looze et al 2014), however it breaks down somewhat in many luminous infrared galaxies (LIRGs; Díaz-Santos et al 2014) and ultra luminous infrared galaxies (ULIRGs; Malhotra et al 1997;Luhman et al 1998;Rigopoulou et al 2014) and even more so in many active galactic nuclei (AGN; Stacey et al 2010, Sargsyan et al 2014, Gullberg et al 2015. The assumption is that there is a deficit in [C ii] luminosity in these sources and in particular in their central regions (Malhotra et al 1997;Luhman et al 1998;Rigopoulou et al 2014;Gullberg et al 2015).…”

Section: Introductionmentioning

confidence: 99%

[C ii] emission from galactic nuclei in the presence of X-rays

Langer

Pineda

2015

A&A

Self Cite

View full text Add to dashboard Cite

Context. The luminosity of [C ii] is used as a probe of the star formation rate in galaxies, but the correlation breaks down in some active galactic nuclei (AGNs). Models of the [C ii] emission from galactic nuclei do not include the influence of X-rays on the carbon ionization balance, which may be a factor in reducing the [C ii] luminosity.Aims. We aim to determine the properties of the ionized carbon and its distribution among highly ionized states in the interstellar gas in galactic nuclei under the influence of X-ray sources. We calculate the [C ii] luminosity in galactic nuclei under the influence of bright sources of soft X-rays. Methods. We solve the balance equation of the ionization states of carbon as a function of X-ray flux, electron, atomic hydrogen, and molecular hydrogen density. These are input to models of [C ii] emission from the interstellar medium (ISM) in galactic nuclei representing conditions in the Galactic central molecular zone and a higher density AGN model. The behavior of the [C ii] luminosity is calculated as a function of the X-ray luminosity. We also solve the distribution of the ionization states of oxygen and nitrogen in highly ionized regions. Results. We find that the dense warm ionized medium (WIM) and dense photon dominated regions (PDRs) dominate the [C ii]emission when no X-rays are present. The X-rays in galactic nuclei can affect strongly the C + abundance in the WIM, converting some fraction to C 2+ and higher ionization states and thus reducing its [C ii] luminosity. For an X-ray luminosity L(X-ray) 10 43 erg s −1 the [C ii] luminosity can be suppressed by a factor of a few, and for very strong sources, L(X-ray) >10 44 erg s −1 such as found for many AGNs, the [C ii] luminosity is significantly depressed. Comparison of the model with several extragalactic sources shows that the [C ii] to far-infrared ratio declines for L(X-ray) 10 43 erg s −1 , in reasonable agreement with our model. Conclusions. We conclude that X-rays can suppress the C + abundance and, therefore, the [C ii] luminosity of the ISM in active galactic nuclei with a large X-ray flux. The X-ray flux can arise from a central massive accreting black hole and/or from many smaller discrete sources distributed throughout the nuclei. We also find that the lower ionization states of nitrogen and oxygen are also suppressed at high X-ray fluxes in warm ionized gas.

show abstract

AHerschel[C II] Galactic plane survey

Cited by 115 publications

References 82 publications

Continuum observations of M 51 and M 83 at 1.1 mm with AzTEC

Continuum observations of M 51 and M 83 at 1.1 mm with AzTEC

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

[C ii] emission from galactic nuclei in the presence of X-rays

Contact Info

Product

Resources

About