scholarly journals The Contribution of AGNs and Star‐forming Galaxies to the Mid‐Infrared as Revealed by Their Spectral Energy Distributions

2008 ◽  
Vol 684 (1) ◽  
pp. 136-152 ◽  
Author(s):  
C. Gruppioni ◽  
F. Pozzi ◽  
M. Polletta ◽  
G. Zamorani ◽  
F. La Franca ◽  
...  
Keyword(s):  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Mid Infrared ◽  
Star Forming

scholarly journals Infrared Spectral Energy Distributions ofz∼ 0.7 Star‐forming Galaxies

2007 ◽  
Vol 670 (1) ◽  
pp. 301-312 ◽  
Author(s):  
Xian Zhong Zheng ◽  
Herve Dole ◽  
Eric F. Bell ◽  
Emeric Le Floc’h ◽  
George H. Rieke ◽  
...  
Keyword(s):  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Star Forming ◽  
Infrared Spectral

scholarly journals Which attenuation curves for star-forming galaxies?

2019 ◽  
Vol 15 (S341) ◽  
pp. 70-73
Author(s):  
Véronique Buat ◽  
David Corre ◽  
Médéric Boquien ◽  
Katarzyna Małek
Keyword(s):  
Radiative Transfer ◽  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Star Forming ◽  
Radiative Transfer Models ◽  
Attenuation Law ◽  
Dust Attenuation ◽  
Attenuation Laws ◽  
Transfer Models

AbstractDust attenuation shapes the spectral energy distributions of galaxies and any modelling and fitting procedure of their spectral energy distributions must account for this process. We present results of two recent works dedicated at measuring the dust attenuation curves in star forming galaxies at redshift from 0.5 to 3, by fitting continuum (photometric) and line (spectroscopic) measurements simultaneously with CIGALE using variable attenuation laws based on flexible recipes. Both studies conclude to a large variety of effective attenuation laws with an attenuation law flattening when the obscuration increases. An extra attenuation is found for nebular lines. The comparison with radiative transfer models implies a flattening of the attenuation law up to near infrared wavelengths, which is well reproduced with a power-laws recipe inspired by the Charlot and Fall recipe. Here we propose a global modification of the Calzetti attenuation law to better reproduce the results of radiative transfer models.

scholarly journals AN ATLAS OF GALAXY SPECTRAL ENERGY DISTRIBUTIONS FROM THE ULTRAVIOLET TO THE MID-INFRARED

2014 ◽  
Vol 212 (2) ◽  
pp. 18 ◽  
Author(s):  
Michael J. I. Brown ◽  
John Moustakas ◽  
J.-D. T. Smith ◽  
Elisabete da Cunha ◽  
T. H. Jarrett ◽  
...  
Keyword(s):  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Mid Infrared

Panchromatic characterisation of accreting black holes in dusty star-forming galaxies

2019 ◽  
Vol 15 (S356) ◽  
pp. 26-26
Author(s):  
Gabriela Calistro Rivera
Keyword(s):  
Galactic Nuclei ◽  
Spectral Energy ◽  
X Rays ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Nuclear Activity ◽  
Star Forming ◽  
History Of ◽  
Fully Bayesian ◽  
The Universe

AbstractAlthough AGN do not typically dominate the bolometric emission of dusty star forming galaxies, large AGN fractions (sometimes > 40%) have been observed in various sub-millimeter surveys. These diagnostics have been however mostly based on X-ray counterpart selections and a complete multiwavength census of the fraction of AGN hosts is needed. I will present new advances in the modelling of panchromatic spectral energy distributions (SEDs) of active galactic nuclei (AGN), based on our publicly available code AGNfitter (Calistro-Rivera et al.2016). AGNfitter implements a fully Bayesian Markov Chain Monte Carlo method to fit the spectral energy distributions of AGNs pushing the wavelengths frontiers from the radio to the X-rays. I will present a recent application of AGNfitter on dusty star forming galaxies in the ALESS submillimeter survey to obtain an unbiased multiwavelength characterisation of the nuclear activity buried in dusty star formation. Our method reveals a significantly larger contribution of AGN activity to the emission in these galaxies than previously observed based on X-rays diagnostics. Our method represents a unique tool to potentially characterise an unbiased accretion history of the Universe when applied to larger populations of star-forming galaxies.

scholarly journals Analysing the spectral energy distributions of Galactic classical Cepheids

2020 ◽  
Vol 635 ◽  
pp. A33 ◽  
Author(s):  
M. A. T. Groenewegen
Keyword(s):  
Near Infrared ◽  
Three Dimensional ◽  
Far Infrared ◽  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Instability Strip ◽  
Energy Distributions ◽  
Infrared Excess ◽  
Mid Infrared ◽  
Classical Cepheids

Spectral energy distributions (SEDs) were constructed for a sample of 477 classical Cepheids (CCs); including stars that have been classified in the literature as such but are probably not. The SEDs were fitted with a dust radiative transfer code. Four stars showed a large mid- or far-infrared excess and the fitting then included a dust component. These comprise the well-known case of RS Pup, and three stars that are (likely) Type-II Cepheids (T2Cs), AU Peg, QQ Per, and FQ Lac. The infrared excess in FQ Lac is reported for the first time in this work. The remainder of the sample was fitted with a stellar photosphere to derive the best-fitting luminosity and effective temperature. Distance and reddening were taken from the literature. The stars were plotted in a Hertzsprung-Russell diagram (HRD) and compared to evolutionary tracks for Cepheids and theoretical instability strips. For the large majority of stars, the position in the HRD is consistent with the instability strip for a CC or T2C. About 5% of the stars are outliers in the sense that they are much hotter or cooler than expected. A comparison to effective temperatures derived from spectroscopy suggests in some cases that the photometrically derived temperature is not correct and that this is likely linked to an incorrectly adopted reddening. Two three-dimensional reddening models have been used to derive alternative estimates of the reddening for the sample. There are significant systematic differences between the two estimates with a non-negligible scatter. In this work the presence of a small near-infrared (NIR) excess, as has been proposed in the literature for a few well-known Cepheids, is investigated. Firstly, this was done by using a sample of about a dozen stars for which a mid-infrared spectrum is available. This data is particularly constraining as the shape of the observed spectrum should match that of the photosphere and any dust spectrum, both dust continuum and any spectral features of, for example, silicates or aluminium oxide. This comparison provides constraints on the dust composition, in agreement with a previous work in the literature. Secondly, the SEDs of all stars were fitted with a dust model to see if a statistically significant better fit could be obtained. The results were compared to recent work. Eight new candidates for exhibiting a NIR excess are proposed, solely based on the photometric SEDs. Obtaining mid-infrared spectra would be needed to confirm this excess. Finally, period-bolometric luminosity and period-radius relations are presented for samples of over 370 fundamental-mode CCs.

scholarly journals Star forming galaxies in the AKARI deep field south: identifications and spectral energy distributions

2010 ◽  
Vol 514 ◽  
pp. A11 ◽  
Author(s):  
K. Małek ◽  
A. Pollo ◽  
T. T. Takeuchi ◽  
P. Bienias ◽  
M. Shirahata ◽  
...  
Keyword(s):  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Star Forming
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