scholarly journals Thermal emission from the amorphous dust: An alternative possibility of the origin of the anomalous microwave emission

2019 ◽  
Vol 72 (1) ◽  
Author(s):  
Masashi Nashimoto ◽  
Makoto Hattori ◽  
Ricardo Génova-Santos ◽  
Frédérick Poidevin
Keyword(s):  
Interstellar Dust ◽  
Amorphous Materials ◽  
Thermal Emission ◽  
Far Infrared ◽  
Alternative Interpretation ◽  
Microwave Emission ◽  
Spectral Energy ◽  
Radiative Processes ◽  
Resonance Emission ◽  
Amorphous Silicate

Abstract Complete studies of the radiative processes of thermal emission from the amorphous dust from microwave through far-infrared wavebands are presented by taking into account, self-consistently for the first time, the standard two-level systems (TLS) model of amorphous materials. The observed spectral energy distributions (SEDs) for the Perseus molecular cloud (MC) and W 43 from microwave through far-infrared are fitted with the SEDs calculated with the TLS model of amorphous silicate. We have found that the model SEDs reproduce the observed properties of the anomalous microwave emission (AME) well. The present result suggests an alternative interpretation for the AME being carried by the resonance emission of the TLS of amorphous materials without introducing new species. Simultaneous fitting of the intensity and polarization SEDs for the Perseus MC and W 43 are also performed. The amorphous model reproduces the overall observed feature of the intensity and polarization SEDs of the Perseus MC and W 43. However, the model’s predicted polarization fraction of the AME is slightly higher than the QUIJOTE upper limits in several frequency bands. A possible improvement of our model to resolve this problem is proposed. Our model predicts that interstellar dust is amorphous materials with very different physical characteristics compared with terrestrial amorphous materials.

scholarly journals Systematic errors in dust mass determinations: insights from laboratory opacity measurements

2020 ◽  
Vol 499 (4) ◽  
pp. 4666-4686
Author(s):  
Lapo Fanciullo ◽  
Francisca Kemper ◽  
Peter Scicluna ◽  
Thavisha E Dharmawardena ◽  
Sundar Srinivasan
Keyword(s):  
Interstellar Dust ◽  
Thermal Emission ◽  
High Redshift ◽  
Synthetic Data ◽  
Far Infrared ◽  
Systematic Errors ◽  
Experimental Measurements ◽  
Dust Mass ◽  
Dusty Galaxies ◽  
Different Temperatures

ABSTRACT The thermal emission of dust is one of the most important tracers of the interstellar medium: multiwavelength photometry in the far-infrared (FIR) and submillimetre (submm) can be fitted with a model, providing estimates of the dust mass. The fit results depend on the assumed value for FIR/submm opacity, which in most models – due to the scarcity, until recently, of experimental measurements – is extrapolated from shorter wavelengths. Lab measurements of dust analogues, however, show that FIR opacities are usually higher than the values used in models and depend on temperature, which suggests that dust mass estimates may be biased. To test the extent of this bias, we create multiwavelength synthetic photometry for dusty galaxies at different temperatures and redshifts, using experimental results for FIR/submm dust opacity and then we fit the synthetic data using standard dust models. We find that the dust masses recovered by typical models are overestimated by a factor of 2–20, depending on how the experimental opacities are treated. If the experimental dust samples are accurate analogues of interstellar dust, therefore, current dust masses are overestimated by up to a factor of 20. The implications for our understanding of dust, both Galactic and at high redshift, are discussed.

scholarly journals The Far-Infrared emission of the first (z ∼ 6) massive galaxies

2019 ◽  
Vol 15 (S352) ◽  
pp. 246-247
Author(s):  
George H. Rieke ◽  
Maria Emilia De Rossi ◽  
Irene Shivaei ◽  
Volker Bromm ◽  
Jianwei Lyu
Keyword(s):  
Interstellar Dust ◽  
Far Infrared ◽  
High Energy ◽  
Infrared Emission ◽  
High Energy Density ◽  
Spectral Energy ◽  
Energy Distributions ◽  
Massive Galaxies ◽  
Very High Energy ◽  
Lower Redshift

AbstractThe first massive galaxies (z ∼ 6) have (1) very high energy density due to their small diameters and extreme luminosities in young stars and (2) interstellar dust relatively deficient in carbon compared with silicates. Both of these attributes should raise their interstellar dust temperatures compared with lower redshift galaxies. Not only is this temperature trend observed, but the high-z spectral energy distributions (SEDs) are very broad due to very warm dust. As a result total infrared luminosities – and star formation rates – at the highest redshifts estimated by fitting blackbodies to submm- and mm-wave observations can be low by a factor of ∼2.

scholarly journals Longslit Optical Spectroscopy of Powerful Far-Infrared Galaxies

1989 ◽  
Vol 134 ◽  
pp. 414-415
Author(s):  
Lee Armus ◽  
Timothy M. Heckman ◽  
George K. Miley
Keyword(s):  
Direct Evidence ◽  
Thermal Emission ◽  
Large Range ◽  
Far Infrared ◽  
Spectral Energy ◽  
Infrared Galaxies ◽  
Energy Distributions ◽  
Hii Region ◽  
The Galaxy ◽  
Infrared Spectral

It has been known since the IRAS mission that there exist galaxies with far-infrared luminosities of 1011–1012Lo, and LFTR/LB = 10–100. Through extensive modelling and observations of HII-region/molecular cloud complexes in the Galaxy, this infrared radiation is believed to be thermal emission from heated dust grains (c.f. review by Stein and Soifer 1983). While starburst models are consistent with the data over a large range in wavelength, direct evidence for sizeable populations of young stars is scarce, and in many cases the presence of an active nucleus either cannot be ruled out, or is required on the basis of energy considerations. In order to better understand the energy source responsible for heating the dust, we have undertaken a spectroscopic survey of galaxies chosen to have far-infrared spectral energy distributions similar to the prototypical class members Arp 220, NGC 6240, NGC 3690, and Mrk 231. It was required that between 25μ and 60μ, α ≤ −1.5, and that between 60μ and 100μ, α ≥ −0.5, where Sv α vα.

scholarly journals Dipolar radiation from spinning dust grains coupled to an electromagnetic wave

2007 ◽  
Vol 73 (4) ◽  
pp. 555-563
Author(s):  
A. GUERREIRO ◽  
M. ELOY ◽  
J. T. MENDONÇA ◽  
R. BINGHAM
Keyword(s):  
Interstellar Dust ◽  
Thermal Emission ◽  
Microwave Emission ◽  
Dust Grains ◽  
Field Frequency ◽  
Background Magnetic Field ◽  
Spectral Components ◽  
Em Field ◽  
Dust Grain ◽  
Independent Parameters

AbstractIn this paper we investigate how the complex rotation and quivering motion of an elongated polarized dust grain in the presence of a monochromatic electromagnetic (EM) wave can produce dipolar emission with two distinct spectral components. We present a model for the emission of radiation by elongated polarized dust grains under the influence of both an external EM wave and a constant background magnetic field. The dust, exhibiting rotational motion at the external EM field frequency ω 0 as well as quivering motion at a frequency Ω0, proportional to the EM field amplitude, will radiate with frequencies that will depend on the external field wavelength and amplitude. The radiated spectra exhibits a frequency around ω0, and sidebands at ω0 ± ω0 and ω0± 2Ω0. Since the amplitude and the frequency of the background EM field are independent parameters, this model establishes a correlation between different spectral components of galactic dipolar emission, which may help to explain the correlation between a component of the Galactic microwave emission and the 100 μ m thermal emission from interstellar dust that has been recently measured.

scholarly journals Low-temperature MIR to submillimeter mass absorption coefficient of interstellar dust analogues

2017 ◽  
Vol 606 ◽  
pp. A50 ◽  
Author(s):  
K. Demyk ◽  
C. Meny ◽  
H. Leroux ◽  
C. Depecker ◽  
J.-B. Brubach ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Interstellar Dust ◽  
Amorphous Materials ◽  
Sol Gel ◽  
Cosmic Dust ◽  
Mass Absorption Coefficient ◽  
Clear Trend ◽  
Mass Absorption ◽  
Amorphous Silicate ◽  
Grain Temperature

Context. To model the cold dust emission observed in the diffuse interstellar medium, in dense molecular clouds or in cold clumps that could eventually form new stars, it is mandatory to know the physical and spectroscopic properties of this dust and to understand its emission. Aims. This work is a continuation of previous studies aiming at providing astronomers with spectroscopic data of realistic cosmic dust analogues for the interpretation of observations. The aim of the present work is to extend the range of studied analogues to iron-rich silicate dust analogues. Methods. Ferromagnesium amorphous silicate dust analogues were produced by a sol-gel method with a mean composition close to Mg1−xFexSiO3 with x = 0.1, 0.2, 0.3, 0.4. Part of each sample was annealed at 500 °C for two hours in a reducing atmosphere to modify the oxidation state of iron. We have measured the mass absorption coefficient (MAC) of these eight ferromagnesium amorphous silicate dust analogues in the spectral domain 30−1000 μm for grain temperature in the range 10−300 K and at room temperature in the 5−40 μm range. Results. The MAC of ferromagnesium samples behaves in the same way as the MAC of pure Mg-rich amorphous silicate samples. In the 30−300 K range, the MAC increases with increasing grain temperature whereas in the range 10−30 K, we do not see any change of the MAC. The MAC cannot be described by a single power law in λ− β. The MAC of the samples does not show any clear trend with the iron content. However the annealing process has, on average, an effect on the MAC that we explain by the evolution of the structure of the samples induced by the processing. The MAC of all the samples is much higher than the MAC calculated by dust models. Conclusions. The complex behavior of the MAC of amorphous silicates with wavelength and temperature is observed whatever the exact silicate composition (Mg vs. Fe amount). It is a universal characteristic of amorphous materials, and therefore of amorphous cosmic silicates, that should be taken into account in astronomical modeling. The enhanced MAC of the measured samples compared to the MAC calculated for cosmic dust model implies that dust masses are overestimated by the models.

scholarly journals Far-infrared star formation rates of six GRB host galaxies with ALMA

2020 ◽  
Vol 496 (4) ◽  
pp. 4405-4419
Author(s):  
Tiger Yu-Yang Hsiao ◽  
Tetsuya Hashimoto ◽  
Jia-Yuan Chang ◽  
Tomotsugu Goto ◽  
Seong Jin Kim ◽  
...  
Keyword(s):  
Star Formation ◽  
Rest Frame ◽  
Thermal Emission ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Far Infrared ◽  
Host Galaxy ◽  
Spectral Energy ◽  
Host Galaxies ◽  
Distribution Fitting

ABSTRACT Gamma-ray bursts (GRBs) can be a promising tracer of cosmic star formation rate history (CSFRH). In order to reveal the CSFRH using GRBs, it is important to understand whether they are biased tracers or not. For this purpose, it is crucial to understand properties of GRB host galaxies, in comparison to field galaxies. In this work, we report ALMA far-infrared (FIR) observations of six z ∼ 2 IR-bright GRB host galaxies, which are selected for the brightness in IR. Among them, four host galaxies are detected for the first time in the rest-frame FIR. In addition to the ALMA data, we collected multiwavelength data from previous studies for the six GRB host galaxies. Spectral energy distribution fitting analyses were performed with cigale to investigate physical properties of the host galaxies, and to test whether active galactic nucleus (AGN) and radio components are required or not. Our results indicate that the best-fitting templates of five GRB host galaxies do not require an AGN component, suggesting the absence of AGNs. One GRB host galaxy, 080207, shows a very small AGN contribution. While derived stellar masses of the three host galaxies are mostly consistent with those in previous studies, interestingly the value of star formation rates (SFRs) of all six GRB hosts are inconsistent with previous studies. Our results indicate the importance of rest-frame FIR observations to correctly estimate SFRs by covering thermal emission from cold dust heated by star formation.

scholarly journals Galactic Far-Infrared Diffuse Emission

2001 ◽  
Vol 204 ◽  
pp. 47-55
Author(s):  
François Boulanger ◽  
Jean-Philippe Bernard ◽  
Guilaine Lagache ◽  
Bertrand Stepnik
Keyword(s):  
Interstellar Dust ◽  
Spectral Energy Distribution ◽  
Dust Emission ◽  
Far Infrared ◽  
Spectral Energy ◽  
Molecular Gas ◽  
Diffuse Emission ◽  
Gas Emission ◽  
Present Understanding ◽  
Small Dust

We review the present understanding of the interstellar dust contribution to the far-IR (λ > 100 μm) sky emission. We show how the contribution from the distinct ISM components (HI, H2, HII gas) are identified and characterized through spatial correlation with gas emission lines. We discuss the spectral energy distribution of the emission from cirrus dust associated with diffuse HI gas and from colder dust associated with molecular gas. We relate the drop in dust emission temperature from the diffuse interstellar medium to molecular gas to an evolution of dust affecting both the abundance of small dust grains and the far-IR emissivity of large grains.

scholarly journals Investigation of the origin of the anomalous microwave emission in Lambda Orionis

2019 ◽  
Author(s):  
Aaron C Bell ◽  
Takashi Onaka ◽  
Frédéric Galliano ◽  
Ronin Wu ◽  
Yasuo Doi ◽  
...  
Keyword(s):  
Interstellar Dust ◽  
Spectral Energy Distribution ◽  
Dust Emission ◽  
Infrared Camera ◽  
Detailed Comparison ◽  
Peak Frequency ◽  
Microwave Emission ◽  
Observational Cosmology ◽  
Spectral Energy ◽  
Dust Mass

AbstractThe anomalous microwave emission (AME) still lacks a conclusive explanation. This excess of emission, roughly between 10 and 50 GHz, tends to defy attempts to explain it as synchrotron or free–free emission. The overlap with frequencies important for cosmic microwave background explorations, combined with a strong correlation with interstellar dust, drive cross-disciplinary collaboration between interstellar medium and observational cosmology. The apparent relationship with dust has prompted a “spinning dust” hypothesis. The typical peak frequency range of the AME profile implicates spinning grains on the order of 1 nm. This points to polycyclic aromatic hydrocarbons (PAHs). We use data from the AKARI/Infrared Camera (IRC), due to its thorough PAH-band coverage, to compare AME from the Planck Collaboration astrophysical component separation product with infrared dust emission in the λ Orionis AME-prominent region. We look also at infrared dust emission from other mid-infrared and far-infrared bands. The results and discussion contained here apply to an angular scale of approximately 1°. We find that dust mass certainly correlates with AME, and that PAH-related emission in the AKARI/IRC 9 μm band correlates slightly more strongly. Using hierarchical Bayesian inference and full-dust spectral energy distribution (SED) modeling we argue that AME in λ Orionis correlates more strongly with PAH mass than with total dust mass, lending support for a spinning PAH hypothesis within this region. We emphasize that future efforts to understand AME should focus on individual regions, and a detailed comparison of the PAH features with the variation of the AME SED.

scholarly journals Accretion and Outflow Activity in the Earliest Phases of Star-Formation: CO, Sub-mm Continuum, and Near-Infrared Observations

1997 ◽  
Vol 163 ◽  
pp. 725-726
Author(s):  
K.-W. Hodapp ◽  
E. F. Ladd
Keyword(s):  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Far Infrared ◽  
Point Sources ◽  
Spectral Energy ◽  
Infrared Observations ◽  
Circumstellar Material ◽  
Dense Cores ◽  
Wavelength Radiation ◽  
Main Component

Stars in the earliest phases of their formation, i.e., those accreting the main component of their final mass, are deeply embedded within dense cores of dust and molecular material. Because of the high line-of-sight extinction and the large amount of circumstellar material, stellar emission is reprocessed by dust into long wavelength radiation, typically in the far-infrared and sub-millimeter bands. Consequently, the youngest sources are strong submillimeter continuum sources, and often undetectable as point sources in the near-infrared and optical. The most deeply embedded of these sources have been labelled “Class 0” sources by André, Ward-Thompson, & Barsony (1994), in an extension of the spectral energy distribution classification scheme first proposed by Adams, Lada, & Shu (1987).

scholarly journals Reproducing the Universe: a comparison between the EAGLE simulations and the nearby DustPedia galaxy sample

2020 ◽  
Vol 494 (2) ◽  
pp. 2823-2838 ◽  
Author(s):  
Ana Trčka ◽  
Maarten Baes ◽  
Peter Camps ◽  
Sharon E Meidt ◽  
James Trayford ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Physical Properties ◽  
Numerical Models ◽  
Far Infrared ◽  
Spectral Energy ◽  
Star Forming ◽  
Star Forming Regions ◽  
Global Emission ◽  
Galaxy Sample ◽  
Galaxy Population

ABSTRACT We compare the spectral energy distributions (SEDs) and inferred physical properties for simulated and observed galaxies at low redshift. We exploit UV-submillimetre mock fluxes of ∼7000 z = 0 galaxies from the EAGLE suite of cosmological simulations, derived using the radiative transfer code skirt. We compare these to ∼800 observed galaxies in the UV-submillimetre range, from the DustPedia sample of nearby galaxies. To derive global properties, we apply the SED fitting code cigale consistently to both data sets, using the same set of ∼80 million models. The results of this comparison reveal overall agreement between the simulations and observations, both in the SEDs and in the derived physical properties, with a number of discrepancies. The optical and far-infrared regimes, and the scaling relations based upon the global emission, diffuse dust, and stellar mass, show high levels of agreement. However, the mid-infrared fluxes of the EAGLE galaxies are overestimated while the far-UV domain is not attenuated enough, compared to the observations. We attribute these discrepancies to a combination of galaxy population differences between the samples and limitations in the subgrid treatment of star-forming regions in the EAGLE-skirt post-processing recipe. Our findings show the importance of detailed radiative transfer calculations and consistent comparison, and provide suggestions for improved numerical models.

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