Probing Interstellar Grain Growth through Polarimetry in the Taurus Cloud Complex

Vaillancourt, John E.; Andersson, B. G.; Clemens, D. P.; Piirola, V.; Hoang, Thiem; Becklin, E. E.; Caputo, Miranda

doi:10.3847/1538-4357/abc6b0

Cited by 16 publications

(16 citation statements)

References 86 publications

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“…Lefèvre et al 2014;Ysard et al 2016;Juvela et al 2020), and (iii) the polarisation (e.g. Fanciullo et al 2017;Vaillancourt et al 2020). Depending on the dust model details and the gas local properties, the accretion of the (sub-)nanometre-sized grains on larger grains is not expected to take more than a hundred to a few thousand years in the outskirts of molecular clouds (e.g.…”

Section: Column Density Mapmentioning

confidence: 99%

Spinning nano-carbon grains: Viable origin for anomalous microwave emission

Ysard

Miville-Deschênes

Verstraete

et al. 2022

A&A

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Context. Excess microwave emission, commonly known as anomalous microwave emission (AME), is now routinely detected in the Milky Way. Although its link with the rotation of interstellar (carbonaceous) nano-grains seems to be relatively well established at cloud scales, large-scale observations show a lack of correlation between the different tracers of nano-carbons and AME, which has led the community to question the viability of this link. Aims. Using ancillary data and spinning dust models for nano-carbons and nano-silicates, we explore the extent to which the AME that come out of the Galactic Plane might originate with one or another carrier. Methods. In contrast to previous large-scale studies, our method is not built on comparing the correlations of the different dust tracers with each other, but rather on comparing the poor correlations predicted by the models with observed correlations. This is based on estimates that are as realistic as possible of the gas ionisation state and grain charge as a function of the local radiation field and gas density. Results. First, nano-carbon dust can explain all the observations for medium properties, in agreement with the latest findings about the separation of cold and warm neutral medium in the diffuse interstellar medium. The dispersion in the observations can be accounted for with little variations in the dust size distribution, abundance, or electric dipole moment. Second, regardless of the properties and abundance of the nano-silicate dust we considered, spinning nano-silicates are excluded as the sole source of the AME. Third, the best agreement with the observations is obtained when the emission of spinning nano-carbons alone is taken into account. However, a marginal participation of nano-silicates in AME production cannot be excluded as long as their abundance does not exceed YSi ∼ 1%.

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Section: Column Density Mapmentioning

confidence: 99%

Spinning nano-carbon grains: Viable origin for anomalous microwave emission

Ysard

Miville-Deschênes

Verstraete

et al. 2022

A&A

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“…Further a marginal correlation between λmax and AV was found (e.g. in studies Whittet et al 2001;Andersson & Potter 2007;Whittet et al 2008;Il'in et al 2018;Vaillancourt et al 2020). We have shown the dependence of λmax on AV in Figure 9a for observed region NGC 2345.…”

Section: Wavelength Of Maximum Polarization As Function Of Extinction...mentioning

confidence: 53%

“…Whittet et al 2008;Il'in et al 2018). However, in some studies Andersson & Potter (2007); Vaillancourt et al (2020), a relatively smaller slopes (≈ 0.03) were found. According to radiative alignment theory, grains are aligned when anisotropic radiation is sufficiently strong to spin-up grains to superthermal rotation (Hoang et al 2021).…”

Section: Implications For Grain Alignment Mechanismsmentioning

confidence: 88%

Polarization, Polarizing Efficiency, and Grain alignment towards the direction of the cluster NGC 2345

Singh,

Pandey,

Hoang

2022

Preprint

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We have investigated the grain alignment and dust properties towards the direction of the cluster NGC 2345 using the multi-band optical polarimetric observations. For the majority of the stars, the observed polarization is found to be due to the interstellar medium with average values of maximum polarization and wavelength corresponding to it as 1.55% and 0.58 µm, respectively. This reveals a similar size distribution of dust grains to that in the general interstellar medium in the direction of NGC 2345. Alteration of dust properties near the distance of 1.2 kpc towards the direction of NGC 2345 has been noticed. The dust grains located beyond this distance are found to be aligned with the Galactic magnetic field, whereas a dispersion in orientation of the dust grains lying in the foreground of this distance is found. Polarizing efficiency of grains in this direction is found to be close to the average efficiency for our Galaxy. The decreased grain size along with the increased polarizing efficiency towards the core region of the cluster indicates the local radiation field is higher within the cluster which is responsible for the increased alignment efficiency of small grains. The wavelength of maximum polarization (associated with the average size of aligned grains) is also found to increase with extinction and reduces with the increase in polarizing efficiency, which can be explained by the radiative torque alignment mechanism.

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“…As an alternative (or complementary) to "super-paramagnetic grains" Purcell (1979) proposed that if the grains could be spun up to rotation speed significantly above the thermal energy of the gas, thermal gas-grain collisions would not be as efficient in randomizing the grain orientation. He suggested that the most likely source of such "suprathermal spins" would be photoelectric emission from the grains and, especially, the ejection of newly formed hydrogen molecules (van de Hulst 1948) from the grain surface.…”

Section: Introductionmentioning

confidence: 99%

Ultraviolet spectropolarimetry with polstar: interstellar medium science

Andersson

Clayton

Doney

et al. 2022

Astrophys Space Sci

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Continuum polarization over the UV-to-microwave range is due to dichroic extinction (or emission) by asymmetric, aligned dust grains. Scattering can also be an important source of polarization, especially at short wavelengths. Because of both grain alignment and scattering physics, the wavelength dependence of the polarization, generally, traces the size of the aligned grains. Similarly because of the differing wavelength dependencies of dichroic extinction and scattering polarization, the two can generally be reliably separated. Ultraviolet (UV) polarimetry therefore provides a unique probe of the smallest dust grains (diameter$< 0.09~\upmu \text{m}$ < 0.09 μm ), their mineralogy and interaction with the environment. However, the current observational status of interstellar UV polarization is very poor with less than 30 lines of sight probed. With the modern, quantitative and well-tested, theory of interstellar grain alignment now available, we have the opportunity to advance the understanding of the interstellar medium (ISM) by executing a systematic study of the UV polarization in the ISM of the Milky Way and near-by galaxies. The Polstar mission will provide the sensitivity and observing time needed to carry out such a program (probing hundreds of stars in the Milky Way and dozens of stars in the LMC/SMC), addressing questions of dust composition as a function of size and location, radiation- and magnetic-field characteristics as well as unveiling the carrier of the 2175 Å extinction feature. In addition, using high-resolution UV line spectroscopy Polstar will search for and probe the alignment of, and polarization from, aligned atoms and ions - so called “Ground State Alignment”, a potentially powerful new probe of magnetic fields in the diffuse ISM.

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Probing Interstellar Grain Growth through Polarimetry in the Taurus Cloud Complex

Cited by 16 publications

References 86 publications

Spinning nano-carbon grains: Viable origin for anomalous microwave emission

Spinning nano-carbon grains: Viable origin for anomalous microwave emission

Polarization, Polarizing Efficiency, and Grain alignment towards the direction of the cluster NGC 2345

Ultraviolet spectropolarimetry with polstar: interstellar medium science

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