ERRATUM: “EXCITATION MECHANISMS FOR HCN (1-0) AND HCO<sup>+</sup> (1-0) IN GALAXIES FROM THE GREAT OBSERVATORIES ALL-SKY LIRG SURVEY” (2015, ApJ, 814, 39)

Privon, George C.; Herrero-Illana, R.; Evans, A. S.; Iwasawa, K.; Pérez-Torres, M. Á.; Armus, L.; Díaz-Santos, T.; Murphy, E. J.; Stierwalt, Sabrina; Aalto, S.; Mazzarella, J. M.; Barcos-Muñoz, Loreto; Borish, H. Jacob; Inami, Hanae; Kim, D.-C.; Treister, Ezequiel; Surace, J.; Lord, S. D.; Conway, J.; Frayer, David; Alberdi, A.

doi:10.3847/1538-4357/835/1/112

Cited by 35 publications

(63 citation statements)

References 1 publication

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“…The ratios of PLCK_G244.8+54.9 are more ambiguous as they lie just at the limit between the two regimes. While this also corroborates the lack of XDR imprints on the high-to-low-J CO line ratios in C18, we emphasize that an enhanced HCO + /HCN is not sufficient to firmly rule out the presence of XDRs (see Privon et al 2015). The elevated cosmic-ray fields expected from the intense star-formation activity of the GEMS may also play an important role in setting the HCO + /HCN ratios in dense cloud cores shielded from UV fields, as argued for instance by Schirm et al (2016) for the Antennae overlap region.…”

Section: Diagnostics From Hco + /Hcnsupporting

confidence: 71%

“…The HCO + /HCN line-intensity ratio is also widely used to discriminate between active galactic nuclei-(AGN) and starburstdominated galaxies, given the apparent dichotomy between both populations (e.g., Krips et al 2008;Imanishi & Nakanishi 2014;Imanishi et al 2016;Izumi et al 2016). Other studies, such as that of Privon et al (2015), nonetheless find additional dependences on ISM density and the surrounding radiation fields (e.g., IRpumping, Krips et al 2008), and demonstrate that HCO + /HCN can strongly vary in LIRGs and ULIRGs experiencing both AGN and star formation feedback within their unresolved central regions. In NGC 1068, the HCO + /HCN ratio is even enhanced by the central AGN (García-Burillo et al 2014).…”

Section: Introductionmentioning

confidence: 99%

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Planck’s Dusty GEMS

Cañameras

Nesvadba²,

Kneißl³

et al. 2021

A&A

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We present ALMA, NOEMA, and IRAM-30 m/EMIR observations of the high-density tracer molecules HCN, HCO + , and HNC in three of the brightest lensed dusty star-forming galaxies at z 3-3.5, part of the Planck's Dusty Gravitationally Enhanced sub-Millimetre Sources (GEMS), with the aim of probing the gas reservoirs closely associated with their exceptional levels of star formation. We obtained robust detections of ten emission lines between J up = 4 and 6, as well as several additional upper flux limits. In PLCK_G244.8+54.9, the brightest source at z = 3.0, the HNC(5-4) line emission at 0.1 resolution, together with other spatially-integrated line profiles, suggests comparable distributions of dense and more diffuse gas reservoirs, at least over the most strongly magnified regions. This rules out any major effect from differential lensing. This line is blended with CN(4-3) and in this source, we measure a HNC(5-4)/CN(4-3) flux ratio of 1.76 ±0. 86. Dense-gas line profiles generally match those of mid-J CO lines, except in PLCK_G145.2+50.8, which also has dense-gas line fluxes that are relatively lower, perhaps due to fewer dense cores and more segregated dense and diffuse gas phases in this source. The HCO + /HCN 1 and HNC/HCN ∼ 1 line ratios in our sample are similar to those of nearby ultraluminous infrared galaxies (ULIRGs) and consistent with photon-dominated regions without any indication of important mechanical heating or active galactic nuclei feedback. We characterize the dense-gas excitation in PLCK_G244.8+54.9 using radiative transfer models assuming pure collisional excitation and find that mid-J HCN, HCO + , and HNC lines arise from a high-density phase with an H 2 density of n ∼ 10 5-10 6 cm −3 , although important degeneracies hinder a determination of the exact conditions. The three GEMS are consistent with extrapolations of dense-gas star-formation laws derived in the nearby Universe, adding further evidence that the extreme star-formation rates observed in the most active galaxies at z ∼ 3 are a consequence of their important dense-gas contents. The dense-gas-mass fractions traced by HCN/[CI] and HCO + /[CI] line ratios are elevated, but not exceptional as compared to other lensed dusty star-forming galaxies at z > 2, and they fall near the upper envelope of local ULIRGs. Despite the higher overall gas fractions and local gas-mass surface densities observed at high redshift, the dense-gas budget of rapidly star-forming galaxies seems to have evolved little between z ∼ 3 and z ∼ 0. Our results favor constant dense-gas depletion times in these populations, which is in agreement with theoretical models of star formation.

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Section: Diagnostics From Hco + /Hcnsupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Planck’s Dusty GEMS

Cañameras

Nesvadba²,

Kneißl³

et al. 2021

A&A

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“…According to Salak et al (2018), all molecular clouds along the SF ring have density and high HCN(1−0)/HCO + (1−0) line ratio (of order ∼1), possibly indicating that the excitation mechanisms are from shocks, free-free emission from Hii regions, and synchrotron emission from SNRs. This ratio even is higher towards the nucleus, with HCN/HCO + ∼ 1.5, which is consistent with the scenario of a composite starburst plus AGN (Privon et al 2015;Salak et al 2018). In addition, they also detected SiO(2−1), a shock tracer, only around the nuclear region of NGC 1808.…”

Section: Ionized and Warm Molecular Gassupporting

confidence: 82%

Black hole feeding and star formation in NGC 1808

Audibert

Combes

García‐Burillo

et al. 2021

A&A

Self Cite

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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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“…The CO (1−0) 1 line, which is associated with a critical density (n c ) on the order of 10 3 cm −3 and an excitation temperature (T ex ) of 5.5 K, has been widely used to trace the total molecular gas content. However, SF occurs mainly in the denser parts of molecular clouds as evidenced by correlations in local (U)LIRGs between L IR and dense gas tracers such as HCN (1−0) (e.g., Gao & Solomom 2004;Wu et al 2005;Privon et al 2015), and heats up the surrounding dense molecular gas substantially. The resulting warm dense gas can be better traced by a mid-J CO line transition, such as CO (6−5), which has n c ∼ 10 5 cm −3 and T ex = 116 K (Carilli & Walter 2013).…”

Section: Introductionmentioning

confidence: 99%

A Herschel Space Observatory Spectral Line Survey of Local Luminous Infrared Galaxies from 194 to 671 Microns

Lu,

Zhao,

Díaz-Santos

et al. 2017

Preprint

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We describe a Herschel Space Observatory 194-671 µm spectroscopic survey of a sample of 121 local luminous infrared galaxies and report the fluxes of the CO J to J−1 rotational transitions for 4 J 13, the [N ii] 205 µm line, the [C i] lines at ⋆ Based on Herschel observations. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

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ERRATUM: “EXCITATION MECHANISMS FOR HCN (1-0) AND HCO⁺ (1-0) IN GALAXIES FROM THE GREAT OBSERVATORIES ALL-SKY LIRG SURVEY” (2015, ApJ, 814, 39)

Cited by 35 publications

References 1 publication

Planck’s Dusty GEMS

Planck’s Dusty GEMS

Black hole feeding and star formation in NGC 1808

A Herschel Space Observatory Spectral Line Survey of Local Luminous Infrared Galaxies from 194 to 671 Microns

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ERRATUM: “EXCITATION MECHANISMS FOR HCN (1-0) AND HCO+ (1-0) IN GALAXIES FROM THE GREAT OBSERVATORIES ALL-SKY LIRG SURVEY” (2015, ApJ, 814, 39)

Cited by 35 publications

References 1 publication

Planck’s Dusty GEMS

Planck’s Dusty GEMS

Black hole feeding and star formation in NGC 1808

A Herschel Space Observatory Spectral Line Survey of Local Luminous Infrared Galaxies from 194 to 671 Microns

Contact Info

Product

Resources

About

ERRATUM: “EXCITATION MECHANISMS FOR HCN (1-0) AND HCO⁺ (1-0) IN GALAXIES FROM THE GREAT OBSERVATORIES ALL-SKY LIRG SURVEY” (2015, ApJ, 814, 39)