Starburst–AGN mixing – II. Optically selected active galaxies

Davies, R. L.; Kewley, Lisa J.; Ho, I-Ting; Dopita, Michael A.

doi:10.1093/mnras/stu1740

Cited by 82 publications

(76 citation statements)

References 131 publications

(164 reference statements)

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“…Note that previous optical and ultraviolet studies of the nucleus of this galaxy have identified it as an AGN plus starforming region. Optical emission line ratios show a smooth transition from AGN-dominated in the centre to star-forming activity in the external regions (Davies et al 2014, and references), while the observed UV and mid-IR spectrum of the nucleus indicates the presence of young star clusters (González Delgado et al 1998) In this galaxy, we identify four regions (Fig. 3 bottom panels): i) the compact [SiVI] emitting region (green points/region) as the AGN-dominated nucleus; ii) the compact and bright Brγ regions (blue points/regions) as the young star-forming clumps in the spiral arm; and iii) the diffuse AGN ionized region (yellow points/region) where weak [SiVI] emission around the nucleus is still detected; and finally iv) the diffuse ionized ISM (white points/regions) in the extranuclear regions where no [SiVI] is detected, and along the spiral arm.…”

Section: Ngc 7130: Prototype Of a Lirg Dominated By A Seyfert 2 Nucleusmentioning

confidence: 97%

Understanding the two-dimensional ionization structure in luminous infrared galaxies

Colina

López

Arribas

et al. 2015

A&A

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We investigate the two-dimensional excitation structure of the interstellar medium (ISM) in a sample of luminous infrared galaxies (LIRGs) and Seyferts using near-IR integral field spectroscopy. This study extends to the near infrared the well-known optical and mid-IR emission line diagnostics used to classify activity in galaxies. Based on the spatially resolved spectroscopy of prototypes, we identify in the [FeII]1.64 µm/Brγ − H 2 2.12 µm/Brγ plane regions dominated by the different heating sources, i.e. active galactic nuclei (AGNs), young main-sequence massive stars, and evolved stars i.e. supernovae. The ISM in LIRGs occupy a wide region in the near-IR diagnostic plane from −0.6 to +1.5 and from −1.2 to +0.8 (in log units) for the [FeII]/Brγ and H 2 /Brγ line ratios, respectively. The corresponding median(mode) ratios are +0.18(0.16) and +0.02(−0.04). Seyferts show on average larger values by factors ∼2.5 and ∼1.4 for the [FeII]/Brγ and H 2 /Brγ ratios, respectively. New areas and relations in the near-IR diagnostic plane are defined for the compact, high surface brightness regions dominated by AGN, young ionizing stars, and supernovae explosions, respectively. In addition to these high surface brightness regions, the diffuse regions affected by the AGN radiation field cover an area similar to that of Seyferts, but with high values in [FeII]/Brγ that are not as extreme. The extended, non-AGN diffuse regions cover a wide area in the near-IR diagnostic diagram that overlaps that of individual excitation mechanisms (i.e. AGN, young stars, and supernovae), but with its mode value to that of the young star-forming clumps. This indicates that the excitation conditions of the extended, diffuse ISM are likely due to a mixture of the different ionization sources, weighted by their spatial distribution and relative flux contribution. The integrated line ratios in LIRGs show higher excitation conditions i.e. towards AGNs, than those measured by the spatially resolved spectroscopy. If this behaviour is representative, it would have clear consequences when classifying high-z, star-forming galaxies based on their near-infrared integrated spectra.

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Section: Ngc 7130: Prototype Of a Lirg Dominated By A Seyfert 2 Nucleusmentioning

confidence: 97%

Understanding the two-dimensional ionization structure in luminous infrared galaxies

Colina

López

Arribas

et al. 2015

A&A

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“…This choice was made so that we need to make no allowance for ambiguity when discussing these populations relative to full SPIRE-selected sample. While it is true that we will miss, by virtue of these selections, those AGN which are less powerful (i.e., primarily lower radio power density populations), hybrid galaxies (e.g., Kewley et al 2001;Davies et al 2014) where the existence of the AGN cannot be proven definitively, and other exotic AGN or AGN-like populations which are discussed later in this section, it is enough for this study that the galaxies we do select here are definitively the hosts of powerful AGN. Four different selection techniques were used in this study to search for the presence of AGNs amongst the SPIRE sample.…”

Section: Active Galactic Nuclei Selection and Classificationmentioning

confidence: 99%

Hidden starbursts and active galactic nuclei at 0 < z < 4 from theHerschel-VVDS-CFHTLS-D1 field: Inferences on coevolution and feedback

Lemaux

Floc’h

Fèvre

et al. 2014

A&A

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We investigate of the properties of ∼2000 Herschel/SPIRE far-infrared-selected galaxies from 0 < z < 4 in the CFHTLS-D1 field. Using a combination of extensive spectroscopy from the VVDS and ORELSE surveys, deep multiwavelength imaging from CFHT, VLA, Spitzer, XMM-Newton, and Herschel, and well-calibrated spectral energy distribution fitting, Herschel-bright galaxies are compared to optically-selected galaxies at a variety of redshifts. Herschel-selected galaxies are observed to span a range of stellar masses, colors, and absolute magnitudes equivalent to galaxies undetected in SPIRE. Though many Herschel galaxies appear to be in transition, such galaxies are largely consistent with normal star-forming galaxies when rest-frame colors are utilized. The nature of the star-forming "main sequence" is studied and we warn against adopting this framework unless the main sequence is determined precisely. Herschel galaxies at different total infrared luminosities (L TIR ) are compared. Bluer optical colors, larger nebular extinctions, and larger contributions from younger stellar populations are observed for galaxies with larger L TIR , suggesting that low-L TIR galaxies are undergoing rejuvenated starbursts while galaxies with higher L TIR are forming a larger percentage of their stellar mass. A variety of methods are used to select powerful active galactic nuclei (AGN). Galaxies hosting all types of AGN are observed to be undergoing starbursts more commonly and vigorously than a matched sample of galaxies without powerful AGN and, additionally, the fraction of galaxies with an AGN increases with increasing star formation rate at all redshifts. At all redshifts (0 < z < 4) the most prodigious star-forming galaxies are found to contain the highest fraction of powerful AGN. For redshift bins that allow a comparison (z > 0.5), the highest L TIR galaxies in a given redshift bin are unobserved by SPIRE at subsequently lower redshifts, a trend linked to downsizing. In conjunction with other results, this evidence is used to argue for prevalent AGN-driven quenching in starburst galaxies across cosmic time.

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“…These publicly accessible data have already allowed the exploration of several different scientific avenues not addressed by the collaboration (e.g., Holwerda & Keel 2013;De Geyter et al 2014;Martínez-García et al 2014;Davies et al 2014;Roche et al 2015;Ho et al 2015). In this article we present the third and final data release (DR3) comprising all observations with good quality.…”

Section: Introductionmentioning

confidence: 99%

CALIFA, the Calar Alto Legacy Integral Field Area survey

Sanchez

García-Benito

Zibetti

et al. 2016

A&A

236

189

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This paper describes the third public data release (DR3) of the Calar Alto Legacy Integral Field Area (CALIFA) survey. Science-grade quality data for 667 galaxies are made public, including the 200 galaxies of the second public data release (DR2). Data were obtained with the integralfield spectrograph PMAS/PPak mounted on the 3.5 m telescope at the Calar Alto Observatory. Three different spectral setups are available: i) a low-resolution V500 setup covering the wavelength range 3745-7500 Å (4240-7140 Å unvignetted) with a spectral resolution of 6.0 Å (FWHM) for 646 galaxies, ii) a medium-resolution V1200 setup covering the wavelength range 3650-4840 Å (3650-4620 Å unvignetted) with a spectral resolution of 2.3 Å (FWHM) for 484 galaxies, and iii) the combination of the cubes from both setups (called COMBO) with a spectral resolution of 6.0 Å and a wavelength range between 3700-7500 Å (3700-7140 Å unvignetted) for 446 galaxies. The Main Sample, selected and observed according to the CALIFA survey strategy covers a redshift range between 0.005 and 0.03, spans the color-magnitude diagram and probes a wide range of stellar masses, ionization conditions, and morphological types. The Extension Sample covers several types of galaxies that are rare in the overall galaxy population and are therefore not numerous or absent in the CALIFA Main Sample. All the cubes in the data release were processed using the latest pipeline, which includes improved versions of the calibration frames and an even further improved image reconstruction quality. In total, the third data release contains 1576 datacubes, including ∼1.5 million independent spectra.

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Starburst–AGN mixing – II. Optically selected active galaxies

Cited by 82 publications

References 131 publications

Understanding the two-dimensional ionization structure in luminous infrared galaxies

Understanding the two-dimensional ionization structure in luminous infrared galaxies

Hidden starbursts and active galactic nuclei at 0 < z < 4 from theHerschel-VVDS-CFHTLS-D1 field: Inferences on coevolution and feedback

CALIFA, the Calar Alto Legacy Integral Field Area survey

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