scholarly journals A detailed dust energy balance study of the Sombrero galaxy

2011 ◽  
Vol 7 (S284) ◽  
pp. 92-96
Author(s):  
Ilse De Looze ◽  
Maarten Baes ◽  
Jacopo Fritz ◽  
Gianfranco Gentile ◽  
Joris Verstappen
Keyword(s):  
Energy Balance ◽  
Standard Model ◽  
Dust Emission ◽  
Balance Study ◽  
Optical Wave ◽  
Dust Clouds ◽  
Star Formation Activity ◽  
Stellar Component ◽  
Dust Component ◽  
Interesting Object

AbstractThe Sombrero galaxy (M104) is an interesting object for a dust energy balance study due to its very symmetric dust lane, its proximity and its (nearly edge-on) inclination of 84°. From a panchromatic radiative transfer analysis, including scattering, absorption and thermal dust re-emission, we construct a standard model for M104 accounting for observations in the optical wave bands (stellar SED, images and extinction profiles in the V and RC band). This standard model underestimates the observed dust emission at infrared wavelengths by a factor of ~ 3, similar to the discrepancy found in other energy balance studies of edge-on spirals. Supplementing this standard model with a young stellar component of low star formation activity in both the inner disk (SFR ~ 0.21 M⊙ yr−1) and dust ring (SFR ~ 0.05 M⊙ yr−1), we are capable of solving the discrepancy in the dust energy budget of the Sombrero galaxy at wavelengths shortwards of 100 μm. To account for the remaining discrepancy at longer wavelengths, we propose a secondary dust component distributed in quiescent clumps. This model with a clumpy dust structure predicts three-quarters of the total dust content to reside in compact dust clouds with no associated embedded sources.

scholarly journals HERschel Observations of Edge-on Spirals (HEROES)

2018 ◽  
Vol 616 ◽  
pp. A120 ◽  
Author(s):  
Aleksandr V. Mosenkov ◽  
Flor Allaert ◽  
Maarten Baes ◽  
Simone Bianchi ◽  
Peter Camps ◽  
...  
Keyword(s):  
Energy Balance ◽  
Near Infrared ◽  
Complex Geometry ◽  
Dust Emission ◽  
Three Dimensional ◽  
Stellar Model ◽  
Small Scale ◽  
Balance Study ◽  
Balance Problem ◽  
Double Exponential

We present results of the detailed dust energy balance study for the seven large edge-on galaxies in the HEROES sample using three-dimensional (3D) radiative transfer (RT) modelling. Based on available optical and near-infrared (NIR) observations of the HEROES galaxies, we derive the 3D distribution of stars and dust in these galaxies. For the sake of uniformity, we apply the same technique to retrieve galaxy properties for the entire sample: we use a stellar model consisting of a Sérsic bulge and three double-exponential discs (a superthin disc for a young stellar population and thin and thick discs for old populations). For the dust component, we adopt a double-exponential disc with the new THEMIS dust-grain model. We fit oligochromatic RT models to the optical and NIR images with the fitting algorithm FITSKIRT and run panchromatic simulations with the SKIRT code at wavelengths ranging from ultraviolet to submillimeter. We confirm the previously stated dust energy balance problem in galaxies: for the HEROES galaxies, the dust emission derived from our RT calculations underestimates the real observations by a factor 1.5–4 for all galaxies except NGC 973 and NGC 5907 (apparently, the latter galaxy has a more complex geometry than we used). The comparison between our RT simulations and the observations at mid-infrared–submillimetre wavelengths shows that most of our galaxies exhibit complex dust morphologies (possible spiral arms, star-forming regions, more extended dust structure in the radial and vertical directions). We suggest that, in agreement with results from the literature, the large- and small-scale structure is the most probable explanation for the dust energy balance problem.

scholarly journals Energy Balance Study of Combined Carbonization and Liquefaction of Coconut Shell

2018 ◽  
Vol 7 (09) ◽  
pp. 2238-2247
Author(s):  
Joshi Priyanka Suhas ◽  
Khot Samreen Anwarali ◽  
A.G. Mohod ◽  
Y.P. Khandetod
Keyword(s):  
Energy Balance ◽  
Coconut Shell ◽  
Balance Study

scholarly journals Dust emission source characterization for visibility hazard assessment on Lordsburg Playa in Southwestern New Mexico, USA

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
R. Scott Van Pelt ◽  
John Tatarko ◽  
Thomas E. Gill ◽  
Chunping Chang ◽  
Junran Li ◽  
...  
Keyword(s):  
New Mexico ◽  
Dust Emission ◽  
Source Area ◽  
Dust Storms ◽  
Economic Losses ◽  
Source Characterization ◽  
Dust Clouds ◽  
Regional Sources ◽  
Dust Events ◽  
Flooded Areas

AbstractIn drylands around the world, ephemeral lakes (playas) are common. Dry, wind-erodible playa sediments are potent local and regional sources of dust and PM10 (airborne particles with diameters less than 10 μm). Dust clouds often cause sudden and/or prolonged loss of visibility to travelers on downwind roadways. Lordsburg Playa, in southwestern New Mexico, USA is bisected by Interstate Highway 10. Dust storms emanating from the playa have been responsible for numerous visibility-related road closures (including 39 road closures between 2012 and 2019) causing major economic losses, in addition to well over a hundred dust-related vehicle crashes causing at least 41 lost lives in the last 53 years. In order to improve understanding of the surfaces responsible for the dust emissions, we investigated the critical wind friction velocity thresholds and the dust emissivities of surfaces representing areas typical of Lordsburg Playa’s stream deltas, shorelines, and ephemerally flooded lakebed using a Portable In-Situ Wind ERosion Laboratory (PI-SWERL). Mean threshold friction velocities for PM10 entrainment ranged from less than 0.30 m s− 1 for areas in the delta and shoreline to greater than 0.55 m s− 1 for ephemerally flooded areas of the lakebed. Similarly, we quantified mean PM10 vertical flux rates ranging from less than 500 μg m− 2 s− 1 for ephemerally flooded areas of lakebed to nearly 25,000 μg m− 2 s− 1 for disturbed delta surfaces. The unlimited PM10 supply of the relatively coarse sediments along the western shoreline is problematic and indicates that this may be the source area for longer-term visibility reducing dust events and should be a focus area for dust mitigation efforts.

The Energy Balance Study: The Design and Baseline Results for a Longitudinal Study of Energy Balance

2013 ◽  
Vol 84 (3) ◽  
pp. 275-286 ◽  
Author(s):  
Gregory A. Hand ◽  
Robin P. Shook ◽  
Amanda E. Paluch ◽  
Meghan Baruth ◽  
E. Patrick Crowley ◽  
...  
Keyword(s):  
Longitudinal Study ◽  
Energy Balance ◽  
Balance Study

scholarly journals ISO Spectra of Planetary Nebulae

2003 ◽  
Vol 209 ◽  
pp. 303-304 ◽  
Author(s):  
Kevin Volk ◽  
Sun Kwok
Keyword(s):  
Chemical Composition ◽  
Dust Emission ◽  
Planetary Nebulae ◽  
Emission Feature ◽  
Significant Fraction ◽  
Energy Output ◽  
Agb Stars ◽  
Dust Component

It has been well known since the IRAS mission that dust emission represents a significant fraction of the energy output from PNe (Zhang & Kwok 1991). Although the dust component in PNe was long thought to be due to the remnants of the envelopes of AGB stars (Kwok 1982), we now know that dust in PNe has a much richer chemical composition. In addition to amorphous silicates and SiC features commonly seen in AGB stars, PNe have been found to have strong aromatic infrared features (Russell et al. 1977), crystalline silicate features (Waters et al. 1997), and an unidentified emission feature at 30 μm (Forrest et al. 1981). In this paper, we show the ISO spectra of a number of PNe illustrating the diverse dust chemistry in PNe.

scholarly journals Role of dust in the microwave emission of galactic halos

2019 ◽  
Vol 34 (37) ◽  
pp. 1950308
Author(s):  
A. Amekhyan ◽  
S. Sargsyan ◽  
A. Stepanian
Keyword(s):  
Galactic Halo ◽  
Dust Emission ◽  
Microwave Emission ◽  
Galactic Halos ◽  
Microwave Frequencies ◽  
Modified Gravity Theories ◽  
Dust Component ◽  
Nearby Galaxies ◽  
Temperature Asymmetry

The contribution of the thermal dust component in galactic halo rotation is explored based on the microwave data of Planck satellite. The temperature asymmetry of Doppler nature revealed for several edge-on galaxies at several microwave frequencies is analyzed regarding the contribution of the thermal dust emission. We derive the dust contribution to the galactic halo rotation using the data in three bands, 353, 545, and 857 GHz for two nearby galaxies M81 and M82. The relevance of the revealed properties on the halo rotation is then discussed in the context of the modified gravity theories proposed to describe the dark matter configurations.

Use of doubly labeled water technique in soldiers training for jungle warfare

1989 ◽  
Vol 67 (1) ◽  
pp. 14-18 ◽  
Author(s):  
C. H. Forbes-Ewan ◽  
B. L. Morrissey ◽  
G. C. Gregg ◽  
D. R. Waters
Keyword(s):  
Energy Balance ◽  
Food Intake ◽  
Energy Expenditure ◽  
Daily Intake ◽  
Doubly Labeled Water ◽  
Daily Energy Expenditure ◽  
Balance Study ◽  
Wide Range ◽  
Daily Energy ◽  
Doubly Labeled Water Method

The doubly labeled water method was used to estimate the energy expended by four members of an Australian Army platoon (34 soldiers) engaged in training for jungle warfare. Each subject received an oral isotope dose sufficient to raise isotope levels by 200–250 (18O) and 100–120 ppm (2H). The experimental period was 7 days. Concurrently, a factorial estimate of the energy expenditure of the platoon was conducted. Also, a food intake-energy balance study was conducted for the platoon. Mean daily energy expenditure by the doubly labeled water method was 4,750 kcal (range 4,152–5,394 kcal). The factorial estimate of mean daily energy expenditure was 4,535 kcal. Because of inherent inaccuracies in the food intake-energy balance technique, we were able to conclude only that energy expenditure, as measured by this method, was greater than the estimated mean daily intake of 4,040 kcal. The doubly labeled water technique was well tolerated, is noninvasive, and appears to be suitable in a wide range of field applications.

scholarly journals Dust energy balance study of two edge-on spiral galaxies in the Herschel-ATLAS survey

2015 ◽  
Vol 451 (2) ◽  
pp. 1728-1739 ◽  
Author(s):  
Gert De Geyter ◽  
Maarten Baes ◽  
Ilse De Looze ◽  
George J. Bendo ◽  
Nathan Bourne ◽  
...  
Keyword(s):  
Energy Balance ◽  
Spiral Galaxies ◽  
Balance Study

scholarly journals Investigations of dust heating in M81, M83 and NGC 2403 with Herschel and Spitzer

2011 ◽  
Vol 7 (S284) ◽  
pp. 97-100
Author(s):  
George J. Bendo ◽  
Keyword(s):  
Star Formation ◽  
Flux Density ◽  
Near Infrared ◽  
Dust Emission ◽  
Far Infrared ◽  
Spectral Energy ◽  
Star Forming ◽  
Star Forming Regions ◽  
Star Formation Activity ◽  
Density Ratios

AbstractWe use Herschel Space Observatory and Spitzer Space Telescope 70-500 μm data along with ground-based optical and near-infrared data to understand how dust heating in the nearby face-on spiral galaxies M81, M83, and NGC 2403 is affected by the starlight from all stars and by the radiation from star-forming regions. We find that 70/160 μm flux density ratios tend to be more strongly influenced by star-forming regions. However, the 250/350 and 350/500 μm micron flux density ratios are more strongly affected by the light from the total stellar populations, suggesting that the dust emission at > 250 μm originates predominantly from a component that is colder than the dust seen at <160 μm and that is relatively unaffected by star formation activity. We conclude by discussing the implications of this for modelling the spectral energy distributions of both nearby and more distant galaxies and for using far-infrared dust emission to trace star formation.

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