The<i>COBE</i>Diffuse Infrared Background Experiment Search for the Cosmic Infrared Background. III. Separation of Galactic Emission from the Infrared Sky Brightness

Arendt, Richard G.; Odegard, N.; Weiland, J. L.; Sodroski, T. J.; Hauser, M. G.; Dwek, Eli; Kelsall, T.; Moseley, S. H.; Silverberg, R. F.; Leisawitz, David; Mitchell, K. J.; Reach, W. T.; Wright, E. L.

doi:10.1086/306381

Cited by 173 publications

(243 citation statements)

References 76 publications

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“…For comparison, the "reference value" commonly adopted for the I 60 µm /I 100 µm ratio in high-latitude cirrus is ∼0.2 (see e.g. Arendt et al 1998). M 81 presents a high color (I 60 µm /I 100 µm ∼ 0.3) compared to Galactic cirrus of the same brightness, although it is not very different from diffuse cirrus colors or from that of the loop itself.…”

Section: Far-infrared Emissionmentioning

confidence: 99%

A multi-wavelength analysis of M 81: insight on the nature of Arp's loop

Sollima

Paz

Martínez–Delgado

et al. 2010

A&A

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Context. The optical ring-like structure detected by Arp (1965) around M 81 (commonly referenced as "Arp's loop") represents one of the most spectacular features observed in nearby galaxies. Arp's loop is commonly interpreted as a tail resulting from the tidal interaction between M 81 and M 82. However, since its discovery the nature of this feature has remained controversial. Aims. Our primary purpose was to identify the sources of optical and infrared emission observed in Arp's loop. Methods. The morphology of Arp's loop has been investigated with deep wide-field optical images. We also measured its colors using IRAS and Spitzer-MIPS infrared images and compared them with those of the disk of M 81 and Galactic dust cirrus that fills the area where M 81 is located. Results. Optical images reveal that this peculiar object has a filamentary structure characterized by many dust features overlapping M 81's field. The ratios of far-infrared fluxes and the estimated dust-to-gas ratios indicate the infrared emission of Arp's loop is dominated by the contribution of cold dust that is most likely from Galactic cirrus. Conclusions. The above results suggest that the light observed at optical wavelengths is a combination of emission from i) a few recent star-forming regions located close to M 81, where both bright UV complexes and peaks in the HI distribution are found, ii) the extended disk of M 81 and iii) scattered light from the same Galactic cirrus that is responsible for the bulk of the far-infrared emission.

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Section: Far-infrared Emissionmentioning

confidence: 99%

A multi-wavelength analysis of M 81: insight on the nature of Arp's loop

Sollima

Paz

Martínez–Delgado

et al. 2010

A&A

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“…Gordon 1995;Wu et al 2007) to the more quiescent diffuse media Arendt et al 1998). Many processes linked to star formation such as stellar winds (Hoefner 2009), supernovae shocks, photodestruction by high-mass stars etc.…”

Section: Introductionmentioning

confidence: 99%

Probing the dust properties of galaxies up to submillimetre wavelengths

Galametz¹,

Madden²,

Galliano³

et al. 2009

A&A

100

200

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Aims. We study the dust properties of four low metallicity galaxies by modelling their spectral energy distributions. This modelling enables us to constrain the dust properties such as the mass, the temperature or the composition to characterise the global ISM properties in dwarf galaxies. Methods. We present 870 μm images of four low metallicity galaxies (NGC 1705, Haro 11, Mrk 1089 and UM 311) observed with the Large APEX BOlometer CAmera (LABOCA) on the Atacama Pathfinder EXperiment (APEX) telescope. We modeled their spectral energy distributions combining the submm observations of LABOCA, 2MASS, IRAS, Spitzer photometric data, and the IRS data for Haro 11. Results. We found that the PAH mass abundance is very low in these galaxies, 5 to 50 times lower than the PAH mass fraction of our Galaxy. We also found that a significant mass of dust is revealed when using submm constraints compared to that measured with only mid-IR to far-IR observations extending only to 160 μm. For NGC 1705 and Haro 11, an excess in submillimeter wavelengths was detected when we used our standard dust SED model. We rerun our SED procedure adding a cold dust component (10 K) to better describe the high 870 μm flux derived from LABOCA observations, which significantly improves the fit. We found that at least 70% of the dust mass of these two galaxies can reside in a cold dust component. We also showed that the subsequent dust-to-gas mass ratios, considering HI and CO observations, can be strikingly high for Haro 11 in comparison with what is usually expected for these low-metallicity environments. Furthermore, we derived the star formation rate of our galaxies and compared them to the Schmidt law. Haro 11 falls anomalously far from the Schmidt relation. These results may suggest that a reservoir of hidden gas could be present in molecular form not traced by the current CO observations. While there can be a significant cold dust mass found in Haro 11, the SED peaks at exceptionally short wavelengths (36 μm), also highlighting the importance of the much warmer dust component heated by the massive star clusters in Haro 11. We also derived the total IR luminosities derived from our models and compared them with relations that derive this luminosity from Spitzer bands. We found that the Draine & Li (2007) formula compares well to our direct IR determinations.

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“…For higher column densities the dust emission systematically exceeds that expected by extrapolating the correlation. Examining specific high Galactic latitude regions, Arendt et al (1998) and Reach et al (1998) found infrared excesses with respect to N HI , with a threshold varying from 1.5 to 5.0 × 10 20 cm −2 .…”

Section: Modelmentioning

confidence: 99%

“…Many studies, mostly using the IRAS and COBE data compared with various 21-cm surveys (Boulanger & Pérault 1988;Joncas et al 1992;Jones et al 1995;Boulanger et al 1996;Arendt et al 1998;Reach et al 1998;Lockman & Condon 2005;MivilleDeschênes et al 2005), have revealed the strong correlation between far-infrared/submm dust emission and 21-cm integrated emission W HI 3 at high Galactic latitudes. In particular Boulanger et al (1996) studied this relation over the whole high Galactic latitude sky.…”

Section: Modelmentioning

confidence: 99%

“…A third source of this excess emission could be dust associated with the Warm Ionized Medium (WIM) but detection of this component is difficult (Arendt et al 1998;Lagache et al 2000) because there is no direct tracer of the ionized gas column density; Hα depends on the square of the electron density and part of the structure seen in Hα might be back-scattering of diffuse Galactic emission on dust and not photons produced within cirrus clouds (Witt et al 2010).…”

Section: Modelmentioning

confidence: 99%

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Planckearly results. XXIV. Dust in the diffuse interstellar medium and the Galactic halo

Abergel

Ade

Aghanim

et al. 2011

A&A

183

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This paper presents the first results from a comparison of Planck dust maps at 353, 545 and 857 GHz, along with IRAS data at 3000 (100 μm) and 5000 GHz (60 μm), with Green Bank Telescope 21-cm observations of H i in 14 fields covering more than 800 deg 2 at high Galactic latitude. The main goal of this study is to estimate the far-infrared to sub-millimeter (submm) emissivity of dust in the diffuse local interstellar medium (ISM) and in the intermediate-velocity (IVC) and high-velocity clouds (HVC) of the Galactic halo. Galactic dust emission for fields with average H i column density lower than 2 × 10 20 cm −2 is well correlated with 21-cm emission because in such diffuse areas the hydrogen is predominantly in the neutral atomic phase. The residual emission in these fields, once the H i-correlated emission is removed, is consistent with the expected statistical properties of the cosmic infrared background fluctuations. The brighter fields in our sample, with an average H i column density greater than 2 × 10 20 cm −2 , show significant excess dust emission compared to the H i column density. Regions of excess lie in organized structures that suggest the presence of hydrogen in molecular form, though they are not always correlated with CO emission. In the higher H i column density fields the excess emission at 857 GHz is about 40% of that coming from the H i, but over all the high latitude fields surveyed the molecular mass faction is about 10%. Dust emission from IVCs is detected with high significance by this correlation analysis. Its spectral properties are consistent with, compared to the local ISM values, significantly hotter dust (T ∼ 20 K), lower submm dust opacity normalized per H-atom, and a relative abundance of very small grains to large grains about four times higher. These results are compatible with expectations for clouds that are part of the Galactic fountain in which there is dust shattering and fragmentation. Correlated dust emission in HVCs is not detected; the average of the 99.9% confidence upper limits to the emissivity is 0.15 times the local ISM value at 857 and 3000 GHz, in accordance with gas phase evidence for lower metallicity and depletion in these clouds. Unexpected anti-correlated variations of the dust temperature and emission cross-section per H atom are identified in the local ISM and IVCs, a trend that continues into molecular environments. This suggests that dust growth through aggregation, seen in molecular clouds, is active much earlier in the cloud condensation and star formation processes.

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TheCOBEDiffuse Infrared Background Experiment Search for the Cosmic Infrared Background. III. Separation of Galactic Emission from the Infrared Sky Brightness

Cited by 173 publications

References 76 publications

A multi-wavelength analysis of M 81: insight on the nature of Arp's loop

A multi-wavelength analysis of M 81: insight on the nature of Arp's loop

Probing the dust properties of galaxies up to submillimetre wavelengths

Planckearly results. XXIV. Dust in the diffuse interstellar medium and the Galactic halo

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