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| 42. |
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| 43. |
- Aalto, Susanne, 1964, et al.
(author)
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Detection of HCN, HCO+, and HNC in the Mrk 231 molecular outflow. Dense molecular gas in the AGN wind
- 2012
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 537, s. 44-51
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Journal article (peer-reviewed)abstract
- We obtained high-resolution (1.''55 × 1.''28) observations of HCN, HCO+, HNC 1-0 and HC3N 10-9 of the ultraluminous galaxy (ULIRG) Mrk 231 with the IRAM Plateau de Bure Interferometer.Results: We detect luminous emission from HCN, HCO+ and HNC 1-0 in the QSO ULIRG Mrk 231. All three lines show broad line wings - which are particularly prominent for HCN. Velocities are found to be similar ( ≈ ± 750 km s-1) to those found for CO 1-0. This is the first time bright HCN, HCO+ and HNC emission has been detected in a large-scale galactic outflow. We find that both the blue- and red-shifted line wings are spatially extended by at least 0.''75 (>700 pc) in a north-south direction. The line wings are brighter (relative to the line center intensity) in HCN than in CO 1-0 and line ratios suggest that the molecular outflow consists of dense (n > 104 cm-3) and clumpy gas with a high HCN abundance X(HCN) > 10-8. These properties are consistent with the molecular gas being compressed and fragmented by shocks in the outflow. Alternatively, HCN is instead pumped by mid-IR continuum, but we propose that this effect is not strong for the spatially extended outflowing gas. In addition, we find that the rotation of the main disk, in east-west direction, is also evident in the HCN, HCO+ and HNC line emission. An unexpectedly bright HC3N 10-9 line is detected inside the central 400 pc of Mrk 231. This HC3N emission may emerge from a shielded, dust-enshrouded region within the inner 40-50 pc where the gas is heated to high temperatures (200-300 K) by the AGN.
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| 44. |
- Aalto, Susanne, 1964, et al.
(author)
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High resolution observations of HCN and HCO+J = 3–2 in the disk and outflow of Mrk 231 -- Detection of vibrationally excited HCN in the warped nucleus
- 2015
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 574, s. 85-
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Journal article (peer-reviewed)abstract
- Aims. Our goal is to study molecular gas properties in nuclei and large scale outflows/winds from active galactic nuclei (AGNs) and starburst galaxies.Methods. We obtained high resolution (0.̋25 to 0.̋90) observations of HCN and HCO+J = 3 → 2 of the ultraluminous QSO galaxy Mrk 231 with the IRAM Plateau de Bure Interferometer (PdBI).Results. We find luminous HCN and HCO+J = 3 → 2 emission in the main disk and we detect compact (r ≲ 0''̣1 (90 pc)) vibrationally excited HCN J = 3 → 2ν2 = 1f emission centred on the nucleus. The velocity field of the vibrationally excited HCN is strongly inclined (position angle PA = 155°) compared to the east-west rotation of the main disk. The nuclear (r ≲ 0.̋1) molecular mass is estimated to 8 × 108 M⊙ with an average N(H2) of 1.2 × 1024 cm-2. Prominent, spatially extended (≳350 pc) line wings are found for HCN J = 3 → 2 with velocities up to ± 750 km s-1. Line ratios indicate that the emission is emerging in dense gas n = 104−5 × 105 cm-3 of elevated HCN abundance X(HCN) = 10-8−10-6. The highest X(HCN) also allows for the emission to originate in gas of more moderate density. We tentatively detect nuclear emission from the reactive ion HOC+ with HCO+/HOC+ = 10−20.Conclusions. The HCN ν2 = 1f line emission is consistent with the notion of a hot, dusty, warped inner disk of Mrk 231 where the ν2 = 1f line is excited by bright mid-IR 14 μm continuum. We estimate the vibrational temperature Tvib to 200−400 K. Based on relative source sizes we propose that 50% of the main HCN emission may have its excitation affected by the radiation field through IR pumping of the vibrational ground state. The HCN emission in the line wings, however, is more extended and thus likely not strongly affected by IR pumping. Our results reveal that dense clouds survive (and/or are formed) in the AGN outflow on scales of at least several hundred pc before evaporating or collapsing. The elevated HCN abundance in the outflow is consistent with warm chemistry possibly related to shocks and/or X-ray irradiated gas. An upper limit to the mass and momentum flux is 4 × 108 M⊙ and 12LAGN/c, respectively, and we discuss possible driving mechanisms for the dense outflow.
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| 45. |
- Burillo, S. G., et al.
(author)
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Molecular gas chemistry in AGN. II. High-resolution imaging of SiO emission in NGC 1068: shocks or XDR?
- 2010
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 519:Article Number: A2
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Journal article (peer-reviewed)abstract
- Context. This paper is part of a multi-species survey of line emission from the molecular gas in the circum-nuclear disk (CND) of the Seyfert 2 galaxy NGC 1068. Unlike in other active galaxies, the intensely star-forming regions in NGC 1068 and the CND can be resolved with current instrumentation. This makes this galaxy an optimal test-bed to probe the effects of AGN on the molecular medium at similar to 100 pc scales. Aims. Single-dish observations have provided evidence that the abundance of silicon monoxide (SiO) in the CND of NGC 1068 is enhanced by 3-4 orders of magnitude with respect to the values typically measured in quiescent molecular gas in the Galaxy. We aim at unveiling the mechanism(s) underlying the SiO enhancement. Methods. We have imaged the emission of the SiO(2-1) (86.8 GHz) and CN(2-1) (226.8 GHz) lines in NGC 1068 at similar to 150 pc and 60 pc spatial resolution with the IRAM Plateau de Bure interferometer (PdBI). We have also obtained complementary IRAM 30 m observations of HNCO and methanol (CH3OH) lines. These species are known as tracers of shocks in the Galaxy. Results. SiO is detected in a disk of similar to 400 pc size around the AGN. SiO abundances in the CND of similar to(1-5) x 10(-9) are about 1-2 orders of magnitude above those measured in the starburst ring. The overall abundance of CN in the CND is high: similar to(0.2-1) x 10(-7). The abundances of SiO and CN are enhanced at the extreme velocities of gas associated with non-circular motions close to the AGN (r
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| 46. |
- Lindberg, Johan, 1984, et al.
(author)
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Evidence for a chemically differentiated outflow in Mrk 231
- 2016
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 587
-
Journal article (peer-reviewed)abstract
- Aims. Our goal is to study the chemical composition of the outflows of active galactic nuclei and starburst galaxies. Methods. We obtained high-resolution interferometric observations of HCN and HCO+ J = 1 -> 0 and J = 2 -> 1 of the ultraluminous infrared galaxy Mrk 231 with the IRAM Plateau de Bure Interferometer. We also use previously published observations of HCN and HCO+ J = 1 -> 0 and J = 3 -> 2, and HNC J = 1 -> 0 in the same source. Results. In the line wings of the HCN, HCO+, and HNC emission, we find that these three molecular species exhibit features at distinct velocities which differ between the species. The features are not consistent with emission lines of other molecular species. Through radiative transfer modelling of the HCN and HCO+ outflow emission we find an average abundance ratio X(HCN) = X(HCO+) greater than or similar to 1000. Assuming a clumpy outflow, modelling of the HCN and HCO+ emission produces strongly inconsistent outflow masses. Conclusions. Both the anti-correlated outflow features of HCN and HCO+ and the different outflow masses calculated from the radiative transfer models of the HCN and HCO+ emission suggest that the outflow is chemically differentiated. The separation between HCN and HCO+ could be an indicator of shock fronts present in the outflow, since the HCN/HCO+ ratio is expected to be elevated in shocked regions. Our result shows that studies of the chemistry in large-scale galactic outflows can be used to better understand the physical properties of these outflows and their effects on the interstellar medium in the galaxy.
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| 47. |
- Rodriguez, M. I., et al.
(author)
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The molecular gas content of ULIRG type 2 quasars at z
- 2014
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 565
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Journal article (peer-reviewed)abstract
- We present new results of CO(1-0) spectroscopic observations of four Sloan Digital Sky Survey (SDSS) type 2 quasars (QSO2) at z similar to 0.3, observed with the 30-m IRAM radio telescope. The QSO2 have infrared luminosities in the ultra-luminous infrared galaxies (ULIRG) regime. We confirm the CO(1-0) detection in one of our four QSO2, SDSS J1543-00, with L-CO' and M-H2 (1.2 +/- 0.2) x 10(10) K km s(-1) pc(2) and (9.4 +/- 1.4) x 10(9) M-circle dot, respectively. The full width at half maximum (FWHM) of the CO(1-0) line is =575 +/- 102 km s(-1). No CO(1-0)) emission is detected in SDSS J0903+02, SDSS j1337-01, SDSS j1520-01 above 3 sigma, yielding upper limits on M(H-2) similar to 9.6, 4.3 and 5.1 x 10(9) M-circle dot, respectively. We expand previous studies of the molecular gas content of intermediate z QSO2 into the ULIRG regime. Taking into account nine QSO2 at z similar to 0.3-1.0 from the literature, we discuss the location of the 13 ULIRG QSO2 at z
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