Nearby early-type galaxies with ionized gas: the UV emission from GALEX observations★

Marino, A.; Rampazzo, R.; Bianchi, Luciana; Annibali, F.; Bressan, A.; Buson, L. M.; Clemens, M.; Panuzzo, P.; Zeilinger, W. W.

doi:10.1111/j.1365-2966.2010.17684.x

Cited by 57 publications

(56 citation statements)

References 65 publications

(116 reference statements)

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“…The source position accuracy is about 0.34 arcseconds and the angular resolution of FUV and NUV is respectively 4.2 and 4.9 arcseconds. We applied a galactic dust extinction correction, A(FUV)/E(B-V)=8.376 A(NUV)/E(B-V)=8.741, to GALEX data, assuming Milky Way dust with R v =3.1 (Cardelli et al 1989;Marino et al 2011). UV emission is a good indicator of the dust content and star formation rate of galaxies when compared with optical data.…”

Section: Uv Datamentioning

confidence: 99%

SPECTRAL ENERGY DISTRIBUTION MAPPING OF TWO ELLIPTICAL GALAXIES ON SUB-kpc SCALES

Amblard¹,

Temi²,

Gaspari³

et al. 2016

ApJ

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We use high-resolution Herschel-PACS data of 2 nearby elliptical galaxies, IC1459 & NGC2768 to characterize their dust and stellar content. IC1459 & NGC2768 have an unusually large amount of dust for elliptical galaxies (1 to 3×10 5 M ), this dust is also not distributed along the stellar content. Using data from GALEX (ultra-violet) to PACS (far-infrared), we analyze the spectral energy distribution (SED) of these galaxies with CIGALEMC as a function of the projected position, binning images in 7.2" pixels. From this analysis, we derive maps of SED parameters, such as the metallicity, the stellar mass, the fraction of young star and the dust mass. The larger amount of dust in FIR maps seems related in our model to a larger fraction of young stars which can reach up to 4% in the dustier area. The young stellar population is fitted as a recent (∼ 0.5 Gyr) short burst of star formation for both galaxies. The metallicities, which are fairly large at the center of both galaxies, decrease with the radial distance with fairly steep gradient for elliptical galaxies.

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Section: Uv Datamentioning

confidence: 99%

SPECTRAL ENERGY DISTRIBUTION MAPPING OF TWO ELLIPTICAL GALAXIES ON SUB-kpc SCALES

Amblard¹,

Temi²,

Gaspari³

et al. 2016

ApJ

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“…4, we study the relationship between stellar population parameters versus morphology on a broader luminosity baseline, by adding the bright ETGs of A07. Sersic indices were measured from SDSS images for 6 galaxies among the subset of the A07 sample (Marino et al 2010). Bulge-to-total light fractions for the A07 sample are not available.…”

Section: Correlations With Morphologymentioning

confidence: 99%

Nature vs. nurture in the low-density environment: structure and evolution of early-type dwarf galaxies in poor groups

Annibali

Grützbauch

Rampazzo

et al. 2011

A&A

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We present the stellar population properties of 13 dwarf galaxies residing in poor groups (low-density environment, LDE) observed with VIMOS at VLT. Ages, metallicities, and [α/Fe] ratios were derived within an r < r e /2 aperture from the Lick indices Hβ, Mgb, Fe5270, and Fe5335 through comparison with our simple stellar population (SSP) models that account for variable [α/Fe] ratios. For a fiducial subsample of 10 early-type dwarfs, we derived median values and scatters around the medians of 5.7 ± 4.4 Gyr, −0.26 ± 0.28, and −0.04 ± 0.33 for age, log Z/Z , and [α/Fe], respectively. For a selection of bright early-type galaxies (ETGs) from an earlier sample residing in a comparable environment, we derive median values of 9.8 ± 4.1 Gyr, 0.06 ± 0.16, and 0.18 ± 0.13 for the same stellar population parameters. It follows that dwarfs are on average younger, less metal rich, and less enhanced in the α-elements than giants, in agreement with the extrapolation to the low-mass regime of the scaling relations derived for giant ETGs. From the total (dwarf+giant) sample, we find that age ∝σ 0.39±0.22 , Z ∝ σ 0.80±0.16 , and α/Fe ∝ σ 0.42±0.22 . We also find correlations with morphology, in the sense that the metallicity and the [α/Fe] ratio increase with the Sersic index n or with the bulge-to-total light fraction B/T . The presence of a strong morphology-[α/Fe] relation appears to contradict the possible evolution along the Hubble sequence from low B/T (low n) to high B/T (high n) galaxies. We also investigate the role played by environment by comparing the properties of our LDE dwarfs with those of Coma red passive dwarfs from the literature. We find possible evidence that LDE dwarfs experienced more prolonged star formations than Coma dwarfs, however larger data samples are needed to draw firmer conclusions.

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“…For the following run2 galaxies, the nebular metallicities lie clearly below the stellar metallicity values: NGC 1169, NGC 2962 (in agreement with Marino et al 2011), and NGC 4394. Only NGC 4394 is classified as a LINER.…”

Section: Comparison Of the Nebular Gas Abundances With The Distributimentioning

confidence: 69%

“…Storchi-Bergmann et al (1994) concluded that both abundance measurements are well-correlated for star-forming galaxies. However, recent work (Marino et al 2011) suggests, as derived from HI and GALEX UV imaging, the presence of current star formation activity in early-type galaxies with emission lines. This sort of galaxy rejuvenation could be due to external gas re-fueling.…”

Section: Comparison Of the Nebular Gas Abundances With The Distributimentioning

confidence: 99%

Ionised gas abundances in barred spiral galaxies

Florido

Pérez

Zurita

et al. 2012

A&A

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Aims. This is the third paper of a series devoted to studying the properties of bars from long-slit spectroscopy to understand their formation, evolution, and influence on the evolution of disk galaxies. In this paper, we aim to determine the gas metallicity distribution of a sample of 20 barred early-type galaxies. We compare the nebular and stellar metallicity distributions to attempt to infer the origin of the warm gas. Methods. We performed long-slit spectroscopy along the bar and obtained metallicities derived using different calibrations. We compare the nebular emission metallicities derived using different semi-empirical methods. We carry out AGN diagnostic diagrams for data at different radii to determine the radius of influence of the AGN and the nature of the galactic nuclei. We then derive the gas metallicities along the bars and compare our results to the distribution of stellar metallicities in the same regions. Results. Most of the gas emission is centrally concentrated, although 15 galaxies also show emission along the bar. In the central regions, gas oxygen abundances are in the range 12 + log(O/H) = 8.4−9.1. The nebular metallicity gradients are very shallow in the bulge and bar regions. For three galaxies (one of them a low-ionization nuclear emission-line region), the gas metallicities lie well below the stellar ones in the bulge region. These results do not depend on the choice of semi-empirical calibration used to calculate the abundances. We see that the galaxies with the lowest metallicities are those with the largest rotational velocities. Unlike our stellar metallicities, we find no correlation between the nebular abundances and the central velocity dispersion. In most galaxies, the gradient in the gas nebular metallicities in the bulge region is shallower than that for the stellar metallicity. Conclusions. The presence of gas of significantly lower metallicity than the stellar abundances in three of our galaxies, suggests that the gas has an external origin that fuels the present star formation at the center of some early-type barred galaxies. That the bar/disk nebular metallicities are higher than the central ones might indicate that the gas could be accreted via cooling flows instead of radial accretion from gas sitting in the outer parts of the disk.

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Nearby early-type galaxies with ionized gas: the UV emission from GALEX observations★

Cited by 57 publications

References 65 publications

SPECTRAL ENERGY DISTRIBUTION MAPPING OF TWO ELLIPTICAL GALAXIES ON SUB-kpc SCALES

SPECTRAL ENERGY DISTRIBUTION MAPPING OF TWO ELLIPTICAL GALAXIES ON SUB-kpc SCALES

Nature vs. nurture in the low-density environment: structure and evolution of early-type dwarf galaxies in poor groups

Ionised gas abundances in barred spiral galaxies

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