Simulations of polarized dust emission

Pelkonen, Veli-Matti; Juvela, M.; Padoan, Paolo

doi:10.1051/0004-6361:20065838

Cited by 33 publications

(52 citation statements)

References 36 publications

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“…In contrast to our work, Pelkonen et al (2007) study much smoother cores in the context of their parental cloud. We restrict ourselves to one isolated core model but calculate its polarized submillimeter emission in great detail.…”

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confidence: 61%

“…We restrict ourselves to one isolated core model but calculate its polarized submillimeter emission in great detail. Pelkonen et al (2007) assume a constant degree of anisotropy of ¼ 0:7 (e.g., Draine & Weingartner 1996), which is a factor of 2 larger than our mass-averaged value. In the context of their smooth cores this approximation may prove to be adequate, although in our calculations the properties of the anisotropy are rather different.…”

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confidence: 76%

“…After this paper was written we learned about the interesting and complementary work of Pelkonen et al (2007), which also extends the CL05 model by applying it to numerical simulations. In contrast to our work, Pelkonen et al (2007) study much smoother cores in the context of their parental cloud.…”

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confidence: 99%

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Polarization of Dust Emission in Clumpy Molecular Clouds and Cores

Bethell

Chepurnov

Lazarían

et al. 2007

ApJ

120

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We observed three molecular clouds and four isolated cores at wavelengths from 3.6− 24 µm. The clouds we observed were Ophiuchus, Perseus, and Serpens and the cores were L204C-2, L1152, L1155C-2, and L1228. Our goal was to use these deep infrared data to map changes in the extinction law and the dust properties throughout the observed regions. In our clouds, we found the lowest density regions have an IRAC extinction law similar to the one observed in the diffuse ISM. At higher extinctions, there is evidence for grain growth because the extinction law flattens compared to the diffuse ISM law and becomes more consistent with a model utilizing larger dust grains. In the densest regions of Serpens and Perseus, A K s ≥ 2, it appears icy mantles are forming on the dust grains. We detected one low extinction region in Perseus with an anomalous extinction law that is not explained by current ideas about grain growth or the formation of ices onto dust grains. The extinction law in the cores shows only a slight flattening of the extinction law with increased extinction. Even at the lowest extinctions, the extinction law is more consistent with a dust model containing grain growth, rather than with the diffuse ISM. Two of the four cores have evidence for ices forming the densest regions. Molecular outflows appear to have an impact on the dust grains in two of our cores: L1152 and L1228. In both our clouds and cores, the extinction law at 24 µm is almost always higher than the value predicted by current dust models, but is consistent with other observations. We find some evidence for the 24 µm extinction law decreasing as the extinction increases. Overall, there are relatively few stars with detections ≥ 3σ at 24 µm. More observations are needed to understand the nature of the extinction law at this wavelength.

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confidence: 61%

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confidence: 76%

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Polarization of Dust Emission in Clumpy Molecular Clouds and Cores

Bethell

Chepurnov

Lazarían

et al. 2007

ApJ

120

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“…Another possibility is an integrated effect in the line of sight: with the increase of the column density there is a dispersion of the alignment along the line of sight. Simulations of the dense cores, more suitable to the context of submillimeter emission, can reproduce this decrease (Falceta-Gonçalves et al 2008;Pelkonen et al 2007). …”

Section: The Average Polarization Of the Interstellar Mediummentioning

confidence: 99%

Correlating the Interstellar Magnetic Field With Protostellar Jets and Its Sources

Targon

Rodrigues

Cerqueira

et al. 2011

ApJ

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This paper combines new CCD polarimetric data with previous information about protostellar objects in a search for correlations involving the interstellar magnetic field (ISMF). Specifically, we carried out an optical polarimetric study of a sample of 28 fields of 10 × 10 located in the neighborhood of protostellar jets and randomly spread over the Galaxy. The polarimetry of a large number of field stars is used to estimate both the average and dispersion of the ISMF direction in each region. The results of the applied statistical tests are as follows. Concerning the alignment between the jet direction and the ISMF, the whole sample does not show alignment. There is, however, a statistically significant alignment for objects of Classes 0 and I. Regarding the ISMF dispersion, our sample presents values slightly larger for regions containing T Tauri objects than for those harboring younger protostars. Moreover, the ISMF dispersion in regions containing high-mass objects tends to be larger than in those including only low-mass protostars. In our sample, the mean interstellar polarization as a function of the average interstellar extinction in a region reaches a maximum value around 3% for A(V ) = 5, after which it decreases. Our data also show a clear correlation of the mean value of the interstellar polarization with the dispersion of the ISMF: the larger the dispersion, the smaller the polarization. Based on a comparison of our and previous results, we suggest that the dispersion in regions forming stars is larger than in quiescent regions.

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“…This will include objects from the early stages of massive stars to the late stages of stellar evolution (Umana et al 2006), from HII regions to dust clouds (Pelkonen et al 2007). Models for both the enrichment of the ISM and the interplay between stellar formation and ambient physical properties will be also tested.…”

Section: Galactic Astrophysicsmentioning

confidence: 99%

Planckpre-launch status: ThePlanck-LFI programme

Mandolesi¹,

Bersanelli

Butler³

et al. 2010

A&A

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This paper provides an overview of the Low Frequency Instrument (LFI) programme within the ESA Planck mission. The LFI instrument has been developed to produce high precision maps of the microwave sky at frequencies in the range 27−77 GHz, below the peak of the cosmic microwave background (CMB) radiation spectrum. The scientific goals are described, ranging from fundamental cosmology to Galactic and extragalactic astrophysics. The instrument design and development are outlined, together with the model philosophy and testing strategy. The instrument is presented in the context of the Planck mission. The LFI approach to ground and inflight calibration is described. We also describe the LFI ground segment. We present the results of a number of tests demonstrating the capability of the LFI data processing centre (DPC) to properly reduce and analyse LFI flight data, from telemetry information to calibrated and cleaned time ordered data, sky maps at each frequency (in temperature and polarization), component emission maps (CMB and diffuse foregrounds), catalogs for various classes of sources (the Early Release Compact Source Catalogue and the Final Compact Source Catalogue). The organization of the LFI consortium is briefly presented as well as the role of the core team in data analysis and scientific exploitation. All tests carried out on the LFI flight model demonstrate the excellent performance of the instrument and its various subunits. The data analysis pipeline has been tested and its main steps verified. In the first three months after launch, the commissioning, calibration, performance, and verification phases will be completed, after which Planck will begin its operational life, in which LFI will have an integral part.

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Simulations of polarized dust emission

Cited by 33 publications

References 36 publications

Polarization of Dust Emission in Clumpy Molecular Clouds and Cores

Polarization of Dust Emission in Clumpy Molecular Clouds and Cores

Correlating the Interstellar Magnetic Field With Protostellar Jets and Its Sources

Planckpre-launch status: ThePlanck-LFI programme

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