Shock Excited Molecules in NGC 1266: Ulirg Conditions at the Center of a Bulge-Dominated Galaxy

Pellegrini, E.; Smith, John David; Wolfire, M. G.; Draine, B. T.; Crocker, Alison F.; Croxall, K. V.; Werf, P. van der; Dale, Daniel A.; Rigopoulou, D.; Wilson, C. D.; Schinnerer, E.; Groves, Brent; Kreckel, Kathryn; Sandström, Karin; Armus, L.; Calzetti, Daniela; Murphy, E. J.; Walter, Fabian; Koda, Jin; Bayet, E.; Beirão, P.; Bolatto, Alberto D.; Bradford, M.; Brinks, E.; Hunt, L. K.; Kennicutt, Robert C.; Knapen, Johan H.; Leroy, Adam K.; Rosolowsky, Erik; Vigroux, L.; Hopwood, R.

doi:10.1088/2041-8205/779/2/l19

Cited by 45 publications

(56 citation statements)

References 31 publications

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“…Considering the good fit with the single temperature component, we do not attempt to add extra components in our RADEX modelling, since it would then introduce additional uncertainties, e.g., how different components are mixed and contribute to each CO transition. One component fitting has been done for both Galactic (e.g., Köhler et al 2014) and extragalactic (e.g., Meijerink et al 2013;Wu et al 2015b) sources, while multiple components (up to three) have been used only in those cases where a single component clearly fails to reproduce the full CO SLEDs (e.g., Rangwala et al 2011;Kamenetzky et al 2012;Pellegrini et al 2013;Israel et al 2014;Kamenetzky et al 2014;Papadopoulos et al 2014;Rosenberg et al 2014;Stock et al 2015). In Section 5.4, however, we discuss the possible presence of a second component in the context of the origin of the CO emission.…”

Section: Discussionmentioning

confidence: 99%

“…18. L CO /L TIR as a function of L TIR for various extragalactic sources: NGC 6240 (Meijerink et al 2013), NGC 1266 (Pellegrini et al 2013), M83 (Wu et al 2015b), Arp 220 (Rangwala et al 2011), M82 (Kamenetzky et al 2012), Mrk 231 (van der Werf et al 2010, and IC 342 (Rigopoulou et al 2013). The sources are color coded based on the dominant heating mechanism: UV photons (red), X-rays (purple), and mechanical heating (blue).…”

Section: Origin Of Shocksmentioning

confidence: 99%

“…In combination with ground-based telescope data, Photodector Array Camera and Spectrometer (PACS; Poglitsch et al 2010), Spectral and Photometric Imaging Receiver (SPIRE; Griffin et al 2010), and Heterodyne Instrument for the Far Infrared (HIFI; de Graauw et al 2010) spectroscopic observations have enabled us to construct CO spectral line energy distributions (SLEDs) from the upper level J u = 1 to 50. In the past several years, Herschel-based CO SLEDs have been extensively examined for a wide range of Galactic (e.g., photodissociation regions (PDRs): Habart et al 2010;Köhler et al 2014;Pon et al 2014;Stock et al 2015;protostars: Larson et al 2015) and extragalactic sources (e.g., infrared (IR)-bright galaxies: Rangwala et al 2011;Kamenetzky et al 2012;Meijerink et al 2013;Pellegrini et al 2013;Greve et al 2014;Lu et al 2014;Papadopoulos et al 2014;Rosenberg et al 2014;Schirm et al 2014;Mashian et al 2015;Wu et al 2015b; Seyfert galaxies: van der Werf et al 2010;Hailey-Dunsheath et al 2012;Israel et al 2014), revealing the ubiquitous presence of warm molecular gas (T k 100 K). Various heating sources, e.g., ultraviolet (UV) photons, X-rays, and cosmic-rays, have been invoked to explain the properties of this warm molecular gas and the emerging picture is that non-ionizing sources such as mechanical heating (e.g., shocks driven by merging activities, stellar winds, and supernova explosions) must play a critical role.…”

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confidence: 99%

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Radiative and mechanical feedback into the molecular gas in the Large Magellanic Cloud

Lee

Madden

Lebouteiller

et al. 2016

A&A

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We present Herschel SPIRE Fourier Transform Spectrometer (FTS) observations of N159W, an active star-forming region in the Large Magellanic Cloud (LMC). In our observations, a number of far-infrared cooling lines including CO J = 4 → 3 to J = 12 → 11, [CI] 609 µm and 370 µm, and [NII] 205 µm are clearly detected. With an aim of investigating the physical conditions and excitation processes of molecular gas, we first construct CO spectral line energy distributions (SLEDs) on ∼10 pc scales by combining the FTS CO transitions with ground-based low-J CO data and analyze the observed CO SLEDs using non-LTE radiative transfer models. We find that the CO-traced molecular gas in N159W is warm (kinetic temperature of 153-754 K) and moderately dense (H 2 number density of (1.1-4.5) × 10 3 cm −3 ). To assess the impact of the energetic processes in the interstellar medium on the physical conditions of the CO-emitting gas, we then compare the observed CO line intensities with the models of photodissociation regions (PDRs) and shocks. We first constrain the properties of PDRs by modelling Herschel observations of [OI] 145 µm, [CII] 158 µm, and [CI] 370 µm fine-structure lines and find that the constrained PDR components emit very weak CO emission. X-rays and cosmic-rays are also found to provide a negligible contribution to the CO emission, essentially ruling out ionizing sources (ultraviolet photons, X-rays, and cosmic-rays) as the dominant heating source for CO in N159W. On the other hand, mechanical heating by low-velocity C-type shocks with ∼10 km s −1 appears sufficient enough to reproduce the observed warm CO.

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Section: Discussionmentioning

confidence: 99%

Section: Origin Of Shocksmentioning

confidence: 99%

mentioning

confidence: 99%

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Radiative and mechanical feedback into the molecular gas in the Large Magellanic Cloud

Lee

Madden

Lebouteiller

et al. 2016

A&A

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“…Finally, the CO spectral line energy distribution (SLED) up to J = 11 reveals highly excited gas in IRAS F08572+3915 (Papadopoulos et al 2010;Pearson et al 2016). While the strong AGN and starburst activity contribute significantly to the high molecular gas excitation, we cannot rule out that shocks resulting from a potential jet-dense ISM play a role in shaping the SLED beyond J ≈ 7 (e.g., Papadopoulos et al 2008;Pellegrini et al 2013).…”

Section: The Origin Of the Fast Gas Blob ∼ 6 Kpc Away From The Galaxymentioning

confidence: 96%

AGN feedback in a galaxy merger: multi-phase, galaxy-scale outflows with a fast molecular gas blob ∼6 kpc away from IRAS F08572+3915

Herrera-Camus

Janssen

Sturm

et al. 2020

A&A

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To understand the role that AGN feedback plays in galaxy evolution we need in-depth studies of the multi-phase structure and energetics of galaxy-wide outflows. In this work we present new, deep (∼ 50 hr) NOEMA CO(1-0) line observations of the molecular gas in the powerful outflow driven by the AGN in the ultra-luminous infrared galaxy IRAS F08572+3915. We spatially resolve the outflow, finding that its most likely configuration is a wide-angle bicone aligned with the kinematic major axis of the rotation disk. The molecular gas in the wind reaches velocities up to approximately ±1200 km s −1 and transports nearly 20% of the molecular gas mass in the system. We detect a second outflow component located ∼ 6 kpc north-west from the galaxy moving away at ∼ 900 km s −1 , which could be the result of a previous episode of AGN activity. The total mass and energetics of the outflow, which includes contributions from the ionized, neutral, warm and cold molecular gas phases is strongly dominated by the cold molecular gas. In fact, the molecular mass outflow rate is higher than the star formation rate, even if we only consider the gas in the outflow that is fast enough to escape the galaxy, which accounts for about ∼40% of the total mass of the outflow. This results in an outflow depletion time for the molecular gas in the central ∼1.5 kpc region of only ∼ 3 Myr, a factor of ∼ 2 shorter than the depletion time by star formation activity.

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“…Some of the highest SFRs in the KINGFISH sample are found in the lenticulars (e.g., NGC 1482, NGC 1377, and NGC 1266); Such intense star-formation activity is not particularly unusual in S0 galaxies (e.g., Amblard et al 2014), although these galaxies are not typical early-type systems. NGC 1377 is a nascent starburst with exceptionally warm dust and a deep silicate absorption feature at 9.7 μm (Vader et al 1993;Laureijs et al 2000;Roussel et al 2006), and NGC 1266 has shock-excited molecular gas entrained in a molecular outflow (e.g., Alatalo et al 2011;Pellegrini et al 2013). Moustakas et al (2010) presented optical long-slit observations and measured oxygen abundances (O/H) and their radial gradients for galaxies in the SINGS sample.…”

Section: The Sample and The Datamentioning

confidence: 99%

Cool dust heating and temperature mixing in nearby star-forming galaxies

Hunt

Draine

Bianchi

et al. 2015

A&A

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Physical conditions of the interstellar medium in galaxies are closely linked to the ambient radiation field and the heating of dust grains. In order to characterize dust properties in galaxies over a wide range of physical conditions, we present here the radial surface brightness profiles of the entire sample of 61 galaxies from Key Insights into Nearby Galaxies: Far-Infrared Survey with Herschel (KINGFISH). The main goal of our work is the characterization of the grain emissivities, dust temperatures, and interstellar radiation fields (ISRFs) responsible for heating the dust. We first fit the radial profiles with exponential functions in order to compare stellar and cool-dust disk scalelengths, as measured by 3.6 μm and 250 μm surface brightnesses. Our results show that the stellar and dust scalelengths are comparable, with a mean ratio of 1.04, although several galaxies show dust-to-stellar scalelength ratios of 1.5 or more. We then fit the far-infrared spectral energy distribution (SED) in each annular region with single-temperature modified blackbodies using both variable (MBBV) and fixed (MBBF) emissivity indices β, as well as with physically motivated dust models. The KINGFISH profiles are well suited to examining trends of dust temperature T dust and β because they span a factor of ∼200 in the ISRF intensity heating the bulk of the dust mass, U min . Results from fitting the profile SEDs suggest that, on average, T dust , dust optical depth τ dust , and U min decrease with radius. The emissivity index β also decreases with radius in some galaxies, but in others is increasing, or rising in the inner regions and falling in the outer ones. Despite the fixed grain emissivity (average β ∼ 2.1) of the physically-motivated models, they are well able to accommodate flat spectral slopes with β < ∼ 1. An analysis of the wavelength variations of dust emissivities in both the data and the models shows that flatter slopes (β < ∼ 1.5) are associated with cooler temperatures, contrary to what would be expected from the usual T dust -β degeneracy. This trend is related to variations in U min since β and U min are very closely linked over the entire range in U min sampled by the KINGFISH galaxies: low U min is associated with flat β < ∼ 1. Both these results strongly suggest that the low apparent β values (flat slopes) in MBBV fits are caused by temperature mixing along the line of sight, rather than by intrinsic variations in grain properties. Finally, a comparison of dust models and the data show a slight ∼10% excess at 500 μm for low metallicity (12 + log (O/H) < ∼ 8) and low far-infrared surface brightness (Σ 500 ).

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Shock Excited Molecules in NGC 1266: Ulirg Conditions at the Center of a Bulge-Dominated Galaxy

Cited by 45 publications

References 31 publications

Radiative and mechanical feedback into the molecular gas in the Large Magellanic Cloud

Radiative and mechanical feedback into the molecular gas in the Large Magellanic Cloud

AGN feedback in a galaxy merger: multi-phase, galaxy-scale outflows with a fast molecular gas blob ∼6 kpc away from IRAS F08572+3915

Cool dust heating and temperature mixing in nearby star-forming galaxies

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