Effects of grain growth on the interstellar polarization curve

Abstract

We apply the time evolution of grain size distributions by accretion and coagulation found in our previous work to the modelling of the wavelength dependence of interstellar linear polarization. We especially focus on the parameters of the Serkowski curve $K$ and ${\lambda }_{\max }$ characterizing the width and the maximum wavelength of this curve, respectively. We use aligned silicate and non-aligned carbonaceous spheroidal particles with different aspect ratios $a/b$. The imperfect alignment of grains with sizes larger than a cut-off size $r_{V,\mathrm{cut}}$ is considered. We find that the evolutionary effects on the polarization curve are negligible in the original model with commonly used material parameters (hydrogen number density $n_{\mathrm{H}}=10^3$ cm${}^{-3}$, gas temperature $T_{\mathrm{gas}}=10$~K, and the sticking probability for accretion $S_{\mathrm{acc}}=0.3$). Therefore, we apply the tuned model where the coagulation threshold of silicate is removed. In this model, ${\lambda }_{\max }$ displaces to the longer wavelengths and the polarization curve becomes wider ($K$ reduces) on time-scales $\sim (30-50)(n_{\mathrm{H}}/10^3{\mathrm{cm}}^{-3}{)}^{-1}$ Myr. The tuned models at $T<30(n_{\mathrm{H}}/10^3{\mathrm{cm}}^{-3}{)}^{-1}$ Myr and different values of the parameters $r_{V,\mathrm{cut}}$ can also explain the observed trend between $K$ and ${\lambda }_{\max }$. It is significant that the evolutionary effect appears in the perpendicular direction to the effect of $r_{V,\mathrm{cut}}$ on the $K$ - ${\lambda }_{\max }$ diagram. Very narrow polarization curves can be reproduced if we change the type of particles (prolate/oblate) and/or vary $a/b$.

9 pages, 6 figures, accepted for publication in MNRAS

References in corpus (12)

• An Analysis of the Shapes of Interstellar Extinction Curves. V. The IR-Through-UV Curve Morphology
• The evolution of amorphous hydrocarbons in the ISM: dust modelling from a new vantage point
• Evolution of interstellar dust and stardust in the solar neighbourhood
• The Efficiency of Grain Alignment in Dense Interstellar Clouds: A Reassessment of Constraints from Near Infrared Polarization
• Shattering and coagulation of dust grains in interstellar turbulence
• A hidden reservoir of Fe/FeS in interstellar silicates?
• Spectropolarimetry of the 3.4 micron Feature in the Diffuse ISM toward the Galactic Center Quintuplet Cluster
• The origin of dust in galaxies revisited: the mechanism determining dust content
• Observational Constraints on Interstellar Grain Alignment
• Tracing the ISM magnetic field morphology: The potential of multi-wavelength polarization measurements
• Modelling interstellar extinction and polarization with spheroidal grains
• Spectropolarimetric Constraints on the Nature of Interstellar Grains

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