SMC: UV Extinction Curves, Gas to Color-Excess Ratios

Lequeux, J.; Maurice, É.; Prévôt, L.; Prevot-Burnichon, M. L.; Rocca‐Volmerange, B.

doi:10.1007/978-94-010-9801-4_88

Cited by 47 publications

(63 citation statements)

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“…The data suggest that the quasar did not show significant variability. As shown in the first panel of Figure 2, the spectral energy distribution (SED) of SDSS J0802+5513 is apparently red as compared to (Lequeux et al 1982;Cartledge et al 2005). SDSS J0802+5513 is detected by FIRST and NVSS at 1.4 GHz in the radio.…”

Section: Broadband Photometrymentioning

confidence: 89%

UNSHIFTED METASTABLE He I* MINI-BROAD ABSORPTION LINE SYSTEM IN THE NARROW-LINE TYPE 1 QUASAR SDSS J080248.18+551328.9

Zhou

Jiang

et al. 2015

ApJ

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We report the identification of an unusual absorption-line system in the quasar SDSS J080248.18 + 551328.9 and present a detailed study of the system, incorporating follow-up optical and near-IR spectroscopy. A few tens of absorption lines are detected, including He i*, Fe ii*, and Ni ii*, which arise from metastable or excited levels, as well as resonant lines in Mg i, Mg ii, Fe ii, Mn ii, and Ca ii. All of the isolated absorption lines show the same profile of width Δv ∼ 1500 km s −1 centered at a common redshift as that of the quasar emission lines, such as [O ii], [S ii], and hydrogen Paschen and Balmer series. With narrow Balmer lines, strong optical Fe ii multiplets, and weak [O iii] doublets, its emission-line spectrum is typical for that of a narrow-line Seyfert 1 galaxy (NLS1). We have derived reliable measurements of the gas-phase column densities of the absorbing ions/levels. Photoionization modeling indicates that the absorber has a density of n H ∼ (1.0-2.5) × 10 5 cm −3 and a column density of N H ∼ (1.0-3.2) × 10 21 cm −2 and is located at R ∼ 100-250 pc from the central supermassive black hole. The location of the absorber, the symmetric profile of the absorption lines, and the coincidence of the absorptionand emission-line centroid jointly suggest that the absorption gas originates from the host galaxy and is plausibly accelerated by stellar processes, such as stellar winds and/or supernova explosions. The implications for the detection of such a peculiar absorption-line system in an NLS1 are discussed in the context of coevolution between supermassive black hole growth and host galaxy buildup.

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Section: Broadband Photometrymentioning

confidence: 89%

UNSHIFTED METASTABLE He I* MINI-BROAD ABSORPTION LINE SYSTEM IN THE NARROW-LINE TYPE 1 QUASAR SDSS J080248.18+551328.9

Zhou

Jiang

et al. 2015

ApJ

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“…This relationship is derived based on the observational results of Lequeux et al (1982), Prevot et al (1984), and Bouchet et al (1985: see also Pei 1992Pettini et al 1998;Smit et al 2015). For each of the z=2-10 sources in our ALMA field, we fit the HST photometry in various bands probing the UV continuum to a power law l b f 1600 1600 ( Å ) to derive a mean flux at ∼1600 Å and also a spectral slope β.…”

Section: Estimates Of the Stellar Mass For Individual Sources In Ourmentioning

confidence: 99%

ALMA SPECTROSCOPIC SURVEY IN THE HUBBLE ULTRA DEEP FIELD: THE INFRARED EXCESS OF UV-SELECTED z = 2–10 GALAXIES AS A FUNCTION OF UV-CONTINUUM SLOPE AND STELLAR MASS

Bouwens

Aravena

Decarli

et al. 2016

ApJ

348

468

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We make use of deep 1.2 mm-continuum observations (12.7µJy/beam RMS) of a 1 arcmin 2 region in the Hubble Ultra Deep Field (HUDF) to probe dust-enshrouded star formation from 330 Lyman-break galaxies spanning the redshift range z = 2-10 (to ∼2-3 M ⊙ /yr at 1σ over the entire range). Given the depth and area of ASPECS, we would expect to tentatively detect 35 galaxies extrapolating the Meurer z ∼ 0 IRX-β relation to z ≥ 2 (assuming T d ∼ 35 K). However, only 6 tentative detections are found at z 2 in ASPECS, with just three at >3σ. Subdividing z = 2-10 galaxies according to stellar mass, U V luminosity, and U V -continuum slope and stacking the results, we only find a significant detection in the most massive (>10 9.75 M ⊙ ) subsample, with an infrared excess (IRX=L IR /L UV ) consistent with previous z ∼ 2 results. However, the infrared excess we measure from our large selection of sub-L * (<10 9.75 M ⊙ ) galaxies is 0.11 +0.32 −0.42 ±0.34 (bootstrap and formal uncertainties) and 0.14 +0.15 −0.14 ±0.18 at z = 2-3 and z = 4-10, respectively, lying below even an SMC IRX-β relation (95% confidence). These results demonstrate the relevance of stellar mass for predicting the IR luminosity of z 2 galaxies. We find that the evolution of the IRX-stellar mass relationship depends on the evolution of the dust temperature. If the dust temperature increases monotonically with redshift (∝ (1 + z) 0.32 ) such that T d ∼ 44-50 K at z ≥ 4, current results are suggestive of little evolution in this relationship to z ∼ 6. We use these results to revisit recent estimates of the z ≥ 3 star-formation rate density.

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“…Therefore, the total Ñux of the Si III] emission lines has been derived by multiplying the Si III] 1883 A emission-line Ñux by a factor of 1.67. The UV emission-line Ñuxes have been corrected for extinction using the reddening law for the Small Magellanic Cloud et al (Pre vot 1984). The electron temperature is derived from a high signal-to-noise ratio MMT spectrum in a ] aper-1A .5 0A .6 ture ).…”

Section: Sbs 1415]437mentioning

confidence: 99%

Heavy‐Element Abundances in Blue Compact Galaxies

Izotov¹,

Thuan²

1999

ApJ

463

130

625

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We present high-quality ground-based spectroscopic observations of 54 supergiant H II regions in 50 low-metallicity blue compact galaxies with oxygen abundances 12 ] log O/H between 7.1 and 8.3. We use the data to determine abundances for the elements N, O, Ne, S, Ar, and Fe. We also analyze Hubble Space T elescope (HST ) Faint Object Spectrograph archival spectra of 10 supergiant H II regions to derive C and Si abundances in a subsample of seven BCGs. The main result of the present study is that none of the heavy elementÈtoÈoxygen abundance ratios studied here ( This constancy (Z ¹ Z _ /20). implies that all of these heavy elements have a primary origin and are produced by the same massive (M º 10 stars responsible for O production. The dispersion of the ratios C/O and N/O in these M _ ) galaxies is found to be remarkably small, being only^0.03 and^0.02 dex, respectively. This very small dispersion is strong evidence against any time-delayed production of C and primary N in the lowest metallicity BCGs (secondary N production is negligible at these low metallicities). The absence of a timedelayed production of C and N is consistent with the scenario that galaxies with 12 ] log O/H ¹ 7.6 are now undergoing their Ðrst burst of star formation, and that they are therefore young, with ages not exceeding 40 Myr. If very low metallicity BCGs are indeed young, this would argue against the commonly held belief that C and N are produced by intermediate-mass (3 stars at very M _ ¹ M ¹ 9 M _ ) low metallicities, as these stars would not have yet completed their evolution in these lowest metallicity galaxies. In higher metallicity BCGs (7.6 \ 12 ] log O/H \ 8.2), the abundance ratios Ne/O, Si/O, S/O, Ar/O, and Fe/O retain the same constant value they had at lower metallicities. By contrast, there is an increase of C/O and N/O along with their dispersions at a given O. We interpret this increase as due to the additional contribution of C and primary N production in intermediate-mass stars, on top of that by high-mass stars. The above results lead to the following timeline for galaxy evolution : (1) all objects with 12 ] log O/H ¹ 7.6 began to form stars less than 40 Myr ago ; (2) after 40 Myr, all galaxies have evolved so that 12 ] log O/H [ 7.6 ; (3) by the time intermediate-mass stars have evolved and released their nucleosynthetic products (100È500 Myr), all galaxies have become enriched to 7.6 \ 12 ] log O/H \ 8.2. The delayed release of primary N at these metallicities greatly increases the scatter in N/O ; (4) later, when galaxies get enriched to 12 ] log O/H [ 8.2, secondary N production becomes important. BCGs show the same O/Fe overabundance with respect to the Sun (D0.4 dex) as Galactic halo stars, suggesting the same chemical enrichment history. We compare heavy elements yields derived from the observed abundance ratios with theoretical yields for massive stars and Ðnd general good agreement. However, the theoretical models are unable to reproduce the observed N/O and Fe/O. Further theoretical developments ...

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SMC: UV Extinction Curves, Gas to Color-Excess Ratios

Cited by 47 publications

References 0 publications

UNSHIFTED METASTABLE He I* MINI-BROAD ABSORPTION LINE SYSTEM IN THE NARROW-LINE TYPE 1 QUASAR SDSS J080248.18+551328.9

UNSHIFTED METASTABLE He I* MINI-BROAD ABSORPTION LINE SYSTEM IN THE NARROW-LINE TYPE 1 QUASAR SDSS J080248.18+551328.9

ALMA SPECTROSCOPIC SURVEY IN THE HUBBLE ULTRA DEEP FIELD: THE INFRARED EXCESS OF UV-SELECTED z = 2–10 GALAXIES AS A FUNCTION OF UV-CONTINUUM SLOPE AND STELLAR MASS

Heavy‐Element Abundances in Blue Compact Galaxies

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