PAH emission variations within the resolved starbursts of NGC 253 and NGC 1808

Tacconi-Garman, L. E.; Sturm, E.; Lehnert, M. D.; Lutz, D.; Davies, R. I.; Moorwood, A. F. M.

doi:10.1051/0004-6361:20035738

Cited by 53 publications

(62 citation statements)

References 69 publications

(129 reference statements)

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“…The fact that the shell detected in the Spitzer observations is undetected in the current study is puzzling in light of our NGC 253 3.3 µm imaging results (Tacconi-Garman et al 2005). In that work we found the first evidence for PAH molecules in a starburst-driven galactic superwind.…”

Section: Inner Kiloparseccontrasting

confidence: 64%

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3.3μm PAH observations of the central kiloparsecs of Centaurus A

Tacconi-Garman¹,

Sturm²

2013

A&A

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Aims. The aim of this work is to further investigate the nature of polycyclic aromatic hydrocarbon (PAH) excitation and emission especially in the context of tracing star formation in a variety of extragalactic environments. Here we turn our attention to the energetic environment of the closest active galactic nucleus (AGN) in our sample, Centaurus A. Methods. Using ISAAC on the ESO VLT UT1 (Antu) we have made high spatial resolution 3.3 µm imaging observations of the central kiloparsec of CenA. These observations have been compared with star formation tracers in the near-and mid-infrared, as well as with mid-infrared tracers of nuclear activity. Results. The nucleus is not devoid of PAH emission, implying that the PAH particles are not destroyed in the nucleus as might be expected for such a harsh environment. However, we see the feature to continuum ratio decrease towards the AGN. As well, the 3.3 µm PAH feature emission generally traces the sites of star formation in Cen A, but in detail there are spatial offsets, consistent with an earlier study of the starburst galaxies NGC 253 and NGC 1808. However, the feature-to-continuum ratio does not drop at the positions of star formation as was previously seen in that earlier study. The cause for this difference remains uncertain. Finally, our data reveal possible evidence for a nearly face-on, circular or spiral, dust structure surrounding the nucleus.

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Section: Inner Kiloparseccontrasting

confidence: 64%

“…High spatial resolution 3 µm imaging has A&A 551, A139 (2013) been obtained for the entire sample, and the results for two starburst galaxies, NGC 253 and NGC 1808, have been published in Tacconi-Garman et al (2005).…”

Section: Introductionmentioning

confidence: 99%

3.3μm PAH observations of the central kiloparsecs of Centaurus A

Tacconi-Garman¹,

Sturm²

2013

A&A

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“…Of normal star forming galaxies or those of low SFR, NGC 5529 and NGC 5907 appear to be the only known examples, thus far (see Table 1). Tacconi-Garman et al (2005) have found a λ 3.3 µm PAH feature in the superwind of the starburst galaxy, NGC 253, with z extent <120 pc, and there is now a clear PAH signature in the halo and superwind of M 82 to a distance of 6 kpc from the plane of that galaxy (Engelbracht et al 2006). Its 8 µm emission, which has a strong PAH component, resembles the Hα emission of the superwind in M 82, indicating that PAHs can survive in such an energetic environment and providing another example of a galaxy in which PAHs correlate with Hα emission in the halo.…”

Section: Discussionmentioning

confidence: 99%

PAHs in the halo of NGC 5529

Irwin¹,

Kennedy²,

Parkin³

et al. 2007

A&A

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We present sensitive ISO λ 6.7 µm observations of the edge-on galaxy, NGC 5529, finding an extensive MIR halo around NGC 5529. The emission is dominated by PAHs in this band. The PAH halo has an exponential scale height of 3.7 kpc but can still be detected as far as ≈10 kpc from the plane to the limits of the high dynamic range (1770/1) data. This is the most extensive PAH halo yet detected in a normal galaxy. This halo shows substructure and the PAHs likely originate from some type of disk outflow. PAHs are long-lived in a halo environment and therefore continuous replenishment from the disk is not required (unless halo PAHs are also being destroyed or removed), consistent with the current low SFR of the galaxy. The PAHs correlate spatially with halo Hα emission, previously observed by Miller & Veilleux (2003, ApJS, 148, 383); both components are likely excited/ionized by in-disk photons that are leaking into the halo. The presence of halo gas may be related to the environment of NGC 5529 which contains at least 17 galaxies in a small group of which NGC 5529 is the dominant member. Of these, we have identified two new companions from the SDSS.Key words. galaxies: general -galaxies: individual: NGC 5529 -galaxies: halos -galaxies: ISM IntroductionNearby edge-on galaxies provide an important local laboratory for understanding physical conditions in the disk-halo interface. This critical region separates two very different environments over a relatively small vertical distance. It plays an important role in a galaxy's energy balance as well as its chemical evolution, since outflows from the disk, circulating "fountains", and possibly infalling external material may each be involved at some point in a galaxy's evolution. Moreover, knowledge of the physical conditions of outflowing gas in nearby galaxies can provide important constraints on galaxy formation scenarios, since outflows (i.e. some form of "feedback") are crucial to these models (e.g. Marri & White 2003, and others). Nearby edgeon galaxies have now been studied in many wavebands showing a variety of interstellar medium (ISM) components above the galactic disk. Indeed, in at least one galaxy that has a high star formation rate (SFR), every component of the interstellar medium, including dust, molecular gas, HI, extra-planar diffuse ionized gas (eDIG, detected by Hα emission) and X-ray emitting hot gas has been detected above the galactic disk (see Lee et al. 2001;and Brar et al. 2003). In each component, discrete disk-halo vertical structures are seen, suggestive of outflow.The recent discovery, from mid-infrared (MIR) observations, of PAH (polycyclic aromatic hydrocarbon) emission 1 in the halo of the low SFR galaxy, NGC 5907 (Irwin & Madden 2006), has prompted a search for other galaxies that may show similar emission. In this paper, we present results for the edge-on galaxy, NGC 5529, using archival data from the Infrared Space 1 There is some uncertainty as to the nature of the carriers of the MIR band emission. In this paper, we adopt the PAH...

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“…Cesarsky et al 1996;Tacconi-Garman et al 2005). In addition, on galactic scales, some of the PAH emission may originate from the diffuse interstellar medium rather than starforming regions, as argued by based on the modeling of the dust emission of SINGS galaxies.…”

Section: Molecular Emission-line Diagnosticsmentioning

confidence: 99%

Energetics of the molecular gas in the H₂luminous radio galaxy 3C 326: Evidence for negative AGN feedback

Nesvadba¹,

Boulanger²,

Salomé

et al. 2010

A&A

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232

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We present a detailed analysis of the gas conditions in the H 2 luminous radio galaxy 3C 326 N at z ∼ 0.1, which has a low starformation rate (SFR ∼ 0.07 M yr −1 ) in spite of a gas surface density similar to those in starburst galaxies. Its star-formation efficiency is likely a factor ∼10−50 lower than those of ordinary star-forming galaxies. Combining new IRAM CO emission-line interferometry with existing Spitzer mid-infrared spectroscopy, we find that the luminosity ratio of CO and pure rotational H 2 line emission is factors 10−100 lower than what is usually found. This suggests that most of the molecular gas is warm. The Na D absorption-line profile of 3C 326 N in the optical suggests an outflow with a terminal velocity of ∼−1800 km s −1 and a mass outflow rate of 30−40 M yr −1 , which cannot be explained by star formation. The mechanical power implied by the wind, of order 10 43 erg s −1 , is comparable to the bolometric luminosity of the emission lines of ionized and molecular gas. To explain these observations, we propose a scenario where a small fraction of the mechanical energy of the radio jet is deposited in the interstellar medium of 3C 326 N, which powers the outflow, and the line emission through a mass, momentum and energy exchange between the different gas phases of the ISM. Dissipation times are of order 10 7−8 yrs, similar or greater than the typical jet lifetime. Small ratios of CO and PAH surface brightnesses in another 7 H 2 luminous radio galaxies suggest that a similar form of AGN feedback could be lowering star-formation efficiencies in these galaxies in a similar way. The local demographics of radio-loud AGN suggests that secular gas cooling in massive early-type galaxies of ≥10 11 M could generally be regulated through a fundamentally similar form of "maintenance-phase" AGN feedback.

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PAH emission variations within the resolved starbursts of NGC 253 and NGC 1808

Cited by 53 publications

References 69 publications

3.3μm PAH observations of the central kiloparsecs of Centaurus A

3.3μm PAH observations of the central kiloparsecs of Centaurus A

PAHs in the halo of NGC 5529

Energetics of the molecular gas in the H₂luminous radio galaxy 3C 326: Evidence for negative AGN feedback

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PAH emission variations within the resolved starbursts of NGC 253 and NGC 1808

Cited by 53 publications

References 69 publications

3.3μm PAH observations of the central kiloparsecs of Centaurus A

3.3μm PAH observations of the central kiloparsecs of Centaurus A

PAHs in the halo of NGC 5529

Energetics of the molecular gas in the H2luminous radio galaxy 3C 326: Evidence for negative AGN feedback

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Energetics of the molecular gas in the H₂luminous radio galaxy 3C 326: Evidence for negative AGN feedback