The Nuclear Stellar Cluster in the Seyfert 1 Galaxy NGC 3227: High Angular Resolution Near‐Infrared Imaging and Spectroscopy

Schinnerer, E.; Eckart, A.; Tacconi, L. J.

doi:10.1086/319052

Cited by 15 publications

(21 citation statements)

References 67 publications

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“…Comparing that to the subarcsecond GTC spectrum, which shows no PAH features, suggests that most star forming activity occurs between 0.3 -3 arcseconds (∼ 20 -270 pc), similar to the comparison of VISIR to Spitzer by Hönig et al (2010); Jensen et al (2017). Schinnerer et al (2001) found a nuclear stellar cluster within ∼ 70 pc of the core. The 12 µm emission estimated from the GTC spectrum accounts for ∼60% of arcsecond-scale emission as determined by Spitzer.…”

Section: Ngc 3227supporting

confidence: 74%

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SOFIA/FORCAST resolves 30–40 μm extended dust emission in nearby active galactic nuclei

Fuller

López-Rodríguez

Packham

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We present arcsecond-scale observations of the active galactic nuclei (AGNs) of seven nearby Seyfert galaxies observed from the Stratospheric Observatory For Infrared Astronomy (SOFIA) using the 31.5 and 37.1 µm filters of the Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST). We isolate unresolved emission from the torus and find extended diffuse emission in six 37.1 µm residual images in our sample. Using Spitzer/IRS spectra, we determine the dominant mid-infrared (MIR) extended emission source and attribute it to dust in the narrow line region (NLR) or star formation. We compare the optical NLR and radio jet axes to the extended 37.1 µm emission and find coincident axes for three sources. For those AGNs with extended emission coincident with the optical axis, we find that spatial scales of the residual images are consistent with 0.1 -1 kpc scale distances to which dust can be heated by the AGN. Using previously published subarcsecond 1 -20 µm imaging and spectroscopic data along with our new observations, we construct broadband spectral energy distributions (SEDs) of the AGNs at wavelengths 1 -40 µm. We find that three AGNs in our sample tentatively show a turnover in the SED between 30 -40 µm. Using results from Clumpy torus models and the Bayesian inference tool BayesClumpy, we find that the posterior outputs for AGNs with MIR turnover revealed by SOFIA/FORCAST have smaller uncertainties than AGNs that do not show a turnover.

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Section: Ngc 3227supporting

confidence: 74%

“…NGC 3227 is another galaxy known for circumnuclear star formation (Schinnerer et al 2001;Rodríguez-Ardila & Viegas 2003;Davies et al 2006). The top left panel of Figure 6 shows the 37.1 µm residual emission, as well as optical emission (Malkan et al 1998) using the F606W HST filter.…”

Section: Ngc 3227mentioning

confidence: 99%

SOFIA/FORCAST resolves 30–40 μm extended dust emission in nearby active galactic nuclei

Fuller

López-Rodríguez

Packham

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…It displays all the possible ingredients found in an AGN: variability in its nucleus (both in the line and continuum Winge et al 1995), a radio jet (Kukula et al 1995), an ionization cone in [O iii] (Mundell et al 1995), a circumnuclear starburst (González Delgado et al 1997), strong X-ray emission (Reichart et al 1985), an inner warp molecular disk (Quillen et al 1999). The NIR images of this galaxy reveal an unresolved nuclear source in the K band and a nuclear stellar cluster that is slightly resolved in the J and H bands, this cluster contributes to about 40-65% of the total emission continuum (Schinnerer et al 2001). The NIR properties of this object have been studied, among others, by Reunanen et al (2003), Schinnerer et al (2001) and Quillen et al (1999).…”

Section: Notes On Individual Objectsmentioning

confidence: 96%

A 0.8–2.4μm spectral atlas of active galactic nuclei

Riffel

Rodríguez-Ardila²,

Pastoriza

2006

A&A

200

286

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Aims. We present a near-infrared spectral atlas of 47 active galactic nuclei (AGN) of all degrees of activity in the wavelength interval of 0.8-2.4 µm, including the fluxes of the observed emission lines. We analyze the spectroscopic properties of the continuum and emission line spectra of the sources. Methods. In order to exclude aperture and seeing effects we used near-infrared spectroscopy in the short cross-dispersed mode (SXD, 0.8-2.4 µm), taking the JHK-bands spectra simultaneously.Results. We present the most extensive NIR spectral atlas of AGN to date. This atlas offers a suitable database for studying the continuum and line emission properties of these objects in a region full of interesting features. The shape of the continuum of QSOs and Sy 1's are similar, being essentially flat in the H and K bands, while a strong variation is found in the J band. In Seyfert 2 galaxies, the continuum in the Fλ × λ space smoothly decreases in flux from 1.2 µm redwards in almost all sources. In J, it smoothly rises bluewards in some sources, while in others a small decrease in flux is observed. The spectra are dominated by strong emission

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“…Further down the Hubble sequence exist such examples as the bright, central cluster in NGC 1705 (Ho & Filippenko, 1996), a dwarf irregular galaxy. Also active galaxies are observed to host NCs in some cases (e.g., Thatte et al 1997;Gallimore & Matthews 2003;Schinnerer et al 2001). In the specific case of late-type spirals, Böker et al (2002, hereafter B02) found that NCs are present in ≈75% of the galaxies.…”

Section: Introductionmentioning

confidence: 99%

Stellar Populations in the Nuclei of Late‐Type Spiral Galaxies

Walcher

Böker

Charlot

et al. 2006

ApJ

211

274

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As part of an ongoing effort to study the stellar nuclei of very late-type, bulgeless spirals, we present results from a high-resolution spectroscopic survey of nine such nuclear star clusters, undertaken with VLT/UVES. We fit the spectra with population synthesis models and measure Lick-type indices to determine mean luminosity-weighted ages, which range from 4.1 × 10 7 to 1.1 × 10 10 years and are insensitive to assumed metallicity or internal extinction. The average metallicity of nuclear clusters in late-type spirals is slightly sub-solar ( Z = 0.015) but shows significant scatter. Most of the clusters have moderate extinctions of 0.1 to 0.3 mags in the I-band. The fits also show that the nuclear cluster spectra are best described by a mix of several generations of stars. This is supported by the fact that only models with composite stellar populations yield mass-tolight ratios that match those obtained from dynamical measurements. For our nine sample clusters, the last star formation episode was on average 34 Myr ago, while all clusters experienced some star formation in the last 100 Myr. We thus conclude that the nuclear clusters undergo repeated episodes of star formation. The robustness of our results with respect to possible contamination from the underlying galaxy disk is demonstrated by comparison to a similar analysis using smaller-aperture spectra obtained with HST/STIS. Combining these results with those from Walcher et al. (2005), we have thus shown that the stellar nuclei of these bulge-less galaxies are massive and dense star clusters that form stars -2recurrently until the present day. This set of properties is unique among the various classes of star clusters. It is almost inevitable to associate these unique properties with the location of the cluster in its host galaxy. It remains a challenging question to elucidate exactly how very late-type spirals manage to create nuclei with such extreme characteristics.

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The Nuclear Stellar Cluster in the Seyfert 1 Galaxy NGC 3227: High Angular Resolution Near‐Infrared Imaging and Spectroscopy

Cited by 15 publications

References 67 publications

SOFIA/FORCAST resolves 30–40 μm extended dust emission in nearby active galactic nuclei

SOFIA/FORCAST resolves 30–40 μm extended dust emission in nearby active galactic nuclei

A 0.8–2.4μm spectral atlas of active galactic nuclei

Stellar Populations in the Nuclei of Late‐Type Spiral Galaxies

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