<i>Herschel</i>-PACS spectroscopic diagnostics of local ULIRGs: Conditions and kinematics in Markarian 231

Fischer, J.; Sturm, E.; González-Alfonso, E.; Graciá-Carpio, J.; Hailey-Dunsheath, S.; Poglitsch, A.; Contursi, A.; Lutz, D.; Genzel, R.; Sternberg, A.; Verma, Aprajita; Tacconi, L. J.

doi:10.1051/0004-6361/201014676

Cited by 268 publications

(316 citation statements)

References 27 publications

(28 reference statements)

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“…However, the outflowing gas is difficult to distinguish from the rotating gas for the relatively low outflow velocities in Arp 220 (Sect. 2.4), in stark contrast with the ∼1000 km s −1 outflow velocities traced by OH in other ULIRGs (Fischer et al 2010;Sturm et al 2011). Nevertheless, clear indication of outflowing gas is seen in the P-Cygni HCO + profiles observed at submillimeter wavelengths (Sakamoto et al 2009) The above independent estimates of the CR energy densities in Arp 220, and the signatures of outflowing molecular gas with low-moderate velocities, appear to be compatible with the scenario of a high density of cosmic rays producing the observed molecular ions.…”

Section: X-rays or Cosmic Rays?contrasting

confidence: 61%

Excited OH⁺, H₂O⁺, and H₃O⁺in NGC 4418 and Arp 220

González-Alfonso

Fischer

Bruderer

et al. 2013

A&A

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107

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We report on Herschel/PACS observations of absorption lines of OH + , H 2 O + and H 3 O + in NGC 4418 and Arp 220. Excited lines of OH + and H 2 O + with E lower of at least 285 and ∼200 K, respectively, are detected in both sources, indicating radiative pumping and location in the high radiation density environment of the nuclear regions. Abundance ratios OH + /H 2 O + of 1−2.5 are estimated in the nuclei of both sources. The inferred OH + column and abundance relative to H nuclei are (0.5−1) × 10 16 cm −2 and ∼2 × 10 −8 , respectively. Additionally, in Arp 220, an extended low excitation component around the nuclear region is found to have OH + /H 2 O + ∼ 5−10. H 3 O + is detected in both sources with N(H 3 O + ) ∼ (0.5−2) × 10 16 cm −2 , and in Arp 220 the pure inversion, metastable lines indicate a high rotational temperature of ∼500 K, indicative of formation pumping and/or hot gas. Simple chemical models favor an ionization sequence dominated by H + → O + → OH + → H 2 O + → H 3 O + , and we also argue that the H + production is most likely dominated by X-ray/cosmic ray ionization. The full set of observations and models leads us to propose that the molecular ions arise in a relatively low density ( 10 4 cm −3 ) interclump medium, in which case the ionization rate per H nucleus (including secondary ionizations) is ζ > 10 −13 s −1 , a lower limit that is several × 10 2 times the highest current rate estimates for Galactic regions. In Arp 220, our lower limit for ζ is compatible with estimates for the cosmic ray energy density inferred previously from the supernova rate and synchrotron radio emission, and also with the expected ionization rate produced by X-rays. In NGC 4418, we argue that X-ray ionization due to an active galactic nucleus is responsible for the molecular ion production.

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Section: X-rays or Cosmic Rays?contrasting

confidence: 61%

Excited OH⁺, H₂O⁺, and H₃O⁺in NGC 4418 and Arp 220

González-Alfonso

Fischer

Bruderer

et al. 2013

A&A

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107

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“…We used the code described in González-Alfonso & Cernicharo (1999), which calculates in spherical symmetry the line excitation due to the dust emission and collisions with H 2 , and includes opacity effects (i.e. radiative trapping), non-local effects, velocity gradients, extinction by dust, and line overlaps (González-Alfonso & Cernicharo 1997). For a given model, the code first calculates the statisticalequilibrium populations in all shells that make up the source, and then the emerging line shapes are computed, convolved with the PACS spectral resolution, and compared directly with the observations.…”

Section: Models and Interpretationmentioning

confidence: 99%

The Mrk 231 molecular outflow as seen in OH

González-Alfonso

Fischer

Graciá-Carpio

et al. 2013

A&A

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We report on the Herschel/PACS observations of OH in Mrk 231, with detections in nine doublets observed within the PACS range, and present radiative-transfer models for the outflowing OH. Clear signatures of outflowing gas are found in up to six OH doublets with different excitation requirements. At least two outflowing components are identified, one with OH radiatively excited, and the other with low excitation, presumably spatially extended and roughly spherical. Particularly prominent, the blue wing of the absorption detected in the in-ladder 2 Π 3/2 J = 9/2−7/2 OH doublet at 65 μm, with E lower = 290 K, indicates that the excited outflowing gas is generated in a compact and warm (circum)nuclear region. Because the excited, outflowing OH gas in Mrk 231 is associated with the warm, far-infrared continuum source, it is most likely more compact (diameter of ∼200−300 pc) than that probed by CO and HCN. Nevertheless, its mass-outflow rate per unit of solid angle as inferred from OH is similar to that previously derived from CO, > ∼ 70 × (2.5 × 10 −6 /X OH ) M yr −1 sr −1 , where X OH is the OH abundance relative to H nuclei. In spherical symmetry, this would correspond to > ∼ 850 × (2.5 × 10 −6 /X OH ) M yr −1 , though significant collimation is inferred from the line profiles. The momentum flux of the excited component attains ∼15 L AGN /c, with an OH column density of (1.5−3) × 10 17 cm −2 and a mechanical luminosity of ∼10 11 L . In addition, the detection of very excited, radiatively pumped OH peaking at central velocities indicates the presence of a nuclear reservoir of gas rich in OH, plausibly the 130 pc scale circumnuclear torus previously detected in OH megamaser emission, that may be feeding the outflow. An exceptional 18 OH enhancement, with OH/ 18 OH < ∼ 30 at both central and blueshifted velocities, is most likely the result of interstellar-medium processing by recent starburst and supernova activity within the circumnuclear torus or thick disk.

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“…An alternative interpretation, motivated by the similarity between the kinematics of molecular and ionized gas and recent discoveries of molecular outflows in several nearby AGN and starburst galaxies (Sakamoto et al 2006;Iono et al 2009;Fischer et al 2010;Feruglio et al 2010;Chung et al 2011;Alatalo et al 2011) is that the broad molecular component could be from gas that is being stirred up and accelerated by the AGN (see also Nesvadba et al 2011b). This is also supported by N-body/SPH models of massive galaxy mergers, which demonstrate that line widths with FWHM ∼ 1000 km s −1 can only be produced through AGN winds (Narayanan et al 2008).…”

Section: Gas Dynamicsmentioning

confidence: 99%

Disk, merger, or outflow? Molecular gas kinematics in two powerful obscured QSOs atz ≥ 3.4

Polletta

Nesvadba

Neri

et al. 2011

A&A

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We report on the detection of bright CO(4-3) line emission in two powerful, obscured quasars discovered in the SWIRE survey, SW022513 and SW022550 at z ≥ 3.4. We analyze the line strength and profile to determine the gas mass, dynamical mass, and the gas dynamics for both galaxies. In SW022513 we may have found the first evidence for a molecular, AGN-driven wind in the early Universe. The line profile in SW022513 is broad (FWHM = 1000 km s −1 ) and blueshifted by −200 km s −1 relative to systemic (where the systemic velocity is estimated from the narrow components of ionized gas lines, as is commonly done for AGN at low and high redshifts). SW022550 has a more regular, double-peaked profile, which is marginally spatially resolved in our data, consistent with either a merger or an extended disk. The molecular gas masses, 4×10 10 M , are large and account for <30% of the stellar mass, making these obscured QSOs as gas rich as other powerful CO emitting galaxies at high redshift, i.e., submillimeter galaxies. Our sources exhibit relatively lower star-formation efficiencies compared to other dusty, powerful starburst galaxies at high redshift. We speculate that this could be a consequence of the AGN perturbing the molecular gas.

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Herschel-PACS spectroscopic diagnostics of local ULIRGs: Conditions and kinematics in Markarian 231

Cited by 268 publications

References 27 publications

Excited OH⁺, H₂O⁺, and H₃O⁺in NGC 4418 and Arp 220

Excited OH⁺, H₂O⁺, and H₃O⁺in NGC 4418 and Arp 220

The Mrk 231 molecular outflow as seen in OH

Disk, merger, or outflow? Molecular gas kinematics in two powerful obscured QSOs atz ≥ 3.4

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Herschel-PACS spectroscopic diagnostics of local ULIRGs: Conditions and kinematics in Markarian 231

Cited by 268 publications

References 27 publications

Excited OH+, H2O+, and H3O+in NGC 4418 and Arp 220

Excited OH+, H2O+, and H3O+in NGC 4418 and Arp 220

The Mrk 231 molecular outflow as seen in OH

Disk, merger, or outflow? Molecular gas kinematics in two powerful obscured QSOs atz ≥ 3.4

Contact Info

Product

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Excited OH⁺, H₂O⁺, and H₃O⁺in NGC 4418 and Arp 220

Excited OH⁺, H₂O⁺, and H₃O⁺in NGC 4418 and Arp 220