Star Formation in the [ITAL]Infrared Space Observatory[/ITAL] Atlas of Bright Spiral Galaxies

Bendo, G. J.; Joseph, R. D.; Wells, Martyn; Gallais, P.; Haas, Martín; Heras, A. M.; Klaas, U.; Laureijs, R. J.; Leech, K.; Lemke, D.; Metcalfe, L.; Rowan-Robinson, M.; Schulz, B.; Telesco, C. M.

doi:10.1086/342283

Cited by 20 publications

(11 citation statements)

References 54 publications

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“…Using the empirical relations of Bell (2003) to convert the radio luminosity into star formation rate, we find ∼1 M ⊙ yr −1 in each case. The radio luminosity is thus consistent with being due to star formation typical for the S0-Sa/b morphology of the host galaxies (Bendo et al 2002).…”

Section: Multi-wavelength Data and Spectral Energy Distributionssupporting

confidence: 72%

THENuSTARVIEW OF NEARBY COMPTON-THICK ACTIVE GALACTIC NUCLEI: THE CASES OF NGC 424, NGC 1320, AND IC 2560

Baloković

Comastri

Harrison

et al. 2014

ApJ

107

105

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We present X-ray spectral analyses for three Seyfert 2 active galactic nuclei, NGC 424, NGC 1320, and IC 2560, observed by NuSTAR in the 3-79 keV band. The high quality hard X-ray spectra allow detailed modeling of the Compton reflection component for the first time in these sources. Using quasi-simultaneous NuSTAR and Swift/XRT data, as well as archival XMM-Newton data, we find that all three nuclei are obscured by Compton-thick material with column densities in excess of ∼ 5 × 10 24 cm −2 , and that their X-ray spectra above 3 keV are dominated by reflection of the intrinsic continuum on Compton-thick material. Due to the very high obscuration, absorbed intrinsic continuum components are not formally required by the data in any of the sources. We constrain the intrinsic photon indices and the column density of the reflecting medium through the shape of the reflection spectra. Using archival multi-wavelength data we recover the intrinsic X-ray luminosities consistent with the broadband spectral energy distributions. Our results are consistent with the reflecting medium being an edge-on clumpy torus with a relatively large global covering factor and overall reflection efficiency of the order of 1%. Given the unambiguous confirmation of the Comptonthick nature of the sources, we investigate whether similar sources are likely to be missed by commonly used selection criteria for Compton-thick AGN, and explore the possibility of finding their high-redshift counterparts.

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Section: Multi-wavelength Data and Spectral Energy Distributionssupporting

confidence: 72%

THENuSTARVIEW OF NEARBY COMPTON-THICK ACTIVE GALACTIC NUCLEI: THE CASES OF NGC 424, NGC 1320, AND IC 2560

Baloković

Comastri

Harrison

et al. 2014

ApJ

107

105

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“…3 there is evidence of a weak correlation between h 850 / R 25 and morphological type. Using Infrared Space Observatory ( ISO ) observations of bright spiral galaxies (Bendo et al 2002), Bendo et al (2003) showed that star formation, as measured by mid‐infrared emission, is indeed more centrally concentrated in early‐type galaxies.…”

Section: Discussionmentioning

confidence: 99%

The distribution of atomic gas and dust in nearby galaxies - III. Radial distributions and metallicity gradients

Thomas¹,

Alexander²,

Clemens

et al. 2004

Monthly Notices of the Royal Astronomical Society

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The radial distribution of dust and gas in 38 nearby galaxies is investigated, using a sample of galaxies for which matched resolution (25 arcsec) neutral hydrogen (H I) and 850-µm images are available. Most of these radial profiles are fitted well by an exponential model, and the derived 850-µm scalelengths are proportional to the H I scalelengths. From this relation, it is found that the metallicity gradients of these galaxies are much shallower than previous studies, unless the dust temperature is constant within the disc, or a significant component of molecular gas exists at large radii that is not traced by CO observations.

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“…The mean SFR ratio for the late-types is 0.85 ± 0.08, implying that we miss ∼ 10−20% of the star formation by assuming that the emission-line gas follows an identical profile to the continuum emission. Star formation that is extended or that occurs preferentially in the outer regions of late type galaxies probably explains this result (e.g., Bendo et al 2002).…”

Section: Star Formation Ratementioning

confidence: 99%

Aperture Effects on Star Formation Rate, Metallicity, and Reddening

Kewley

Jansen²,

Geller³

2005

PUBL ASTRON SOC PAC

241

299

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We use 101 galaxies selected from the Nearby Field Galaxy Survey (NFGS) to investigate the effect of aperture size on the star formation rate, metallicity and reddening determinations for galaxies. Our sample includes galaxies of all Hubble types except ellipticals with global SFRs ranging from 0.01 to 100 M ⊙ yr −1 , metallicities between 7.9 log(O/H) + 12 9.0, and reddening between 0 A(V ) 3.3. We compare the star formation rate, metallicity and reddening derived from nuclear spectra to those derived from integrated spectra. For apertures capturing < 20% of the B 26 light, the differences between nuclear and global metallicity, extinction and star formation rate are substantial. Latetype spiral galaxies show the largest systematic difference of ∼ 0.14 dex in the sense that nuclear metallicities are greater than the global metallicities. Sdm, Im, and Peculiar types have the largest scatter in nuclear/integrated metallicities, indicating a large range in metallicity gradients for these galaxy types or clumpy metallicity distributions. We find little evidence for systematic differences between nuclear and global extinction estimates for any galaxy type. However, there is significant scatter between the nuclear and integrated extinction estimates for nuclear apertures containing < 20% of the B 26 flux. We calculate an 'expected' star formation rate using our nuclear spectra and apply the commonly-used aperture correction method. The expected star formation rate overestimates the global value for early type spirals, with large scatter for all Hubble types, particularly late types. The differences between the expected and global star formation rates probably result from the assumption that the distributions of the emission-line gas and the continuum are identical. The largest scatter (error) in the estimated SFR occurs when the aperture captures < 20% of the B 26 emission. We discuss the implications of these results for metallicity-luminosity relations and star-formation history studies based on fiber spectra. To reduce systematic and random errors from aperture effects, we recommend selecting samples with fibers that capture > 20% of the galaxy light. For the Sloan Digital Sky Survey and the 2dFGRS, redshifts z > 0.04 and z > 0.06 are required, respectively, to ensure a covering fraction > 20% for galaxy sizes similar to the average size, type, and luminosity observed in our sample. Higher-luminosity samples and samples containing many late-type galaxies require a larger minimum redshift to ensure that > 20% of the galaxy light is enclosed by the fiber.

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Star Formation in the [ITAL]Infrared Space Observatory[/ITAL] Atlas of Bright Spiral Galaxies

Cited by 20 publications

References 54 publications

THENuSTARVIEW OF NEARBY COMPTON-THICK ACTIVE GALACTIC NUCLEI: THE CASES OF NGC 424, NGC 1320, AND IC 2560

THENuSTARVIEW OF NEARBY COMPTON-THICK ACTIVE GALACTIC NUCLEI: THE CASES OF NGC 424, NGC 1320, AND IC 2560

The distribution of atomic gas and dust in nearby galaxies - III. Radial distributions and metallicity gradients

Aperture Effects on Star Formation Rate, Metallicity, and Reddening

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