Using the Starlight Polarization Efficiency Integral to Constrain Shapes and Porosities of Interstellar Grains
نویسندگان
چکیده
We have developed a new method for using the observed starlight polarization and polarized submillimeter emission to constrain shapes porosities of interstellar grains. first present modified picket-fence approximation verify that it is sufficiently accurate modeling polarization. then introduce integral Πobs as measure overall strength starlight, efficiency Φ characterize effectiveness different grain types producing starlight. The ratio Πobs/Φ determines mass-weighted alignment 〈falign〉 Approximating aligned grains in ISM spheroids, we use show constrains minimum degree asphericity. For porosity , axial ∼1.4 oblate or ∼1.8 prolate spheroids. If are porous, more extreme ratios required. same produce able provide at wavelengths but with further limits on shape porosity. Porosities ruled out. can be approximated by "astrodust" predict 10 μm pV: p(10 μm)/pV = 0.219 ± 0.029. Cyg OB2-12, μm) (2.1 0.3)%, which should observable.
منابع مشابه
Constraining the Porosities of Interstellar Dust Grains
We present theoretical calculations of the X-ray scattering properties of porous grain aggregates with olivine monomers. The small and large angle scattering properties of these aggregates are governed by the global structure and substructure of the grain, respectively. We construct two diagnostics, RX and TX, based on the optical and X-ray properties of the aggregates, and apply them to a Chan...
متن کاملassessment of the efficiency of s.p.g.c refineries using network dea
data envelopment analysis (dea) is a powerful tool for measuring relative efficiency of organizational units referred to as decision making units (dmus). in most cases dmus have network structures with internal linking activities. traditional dea models, however, consider dmus as black boxes with no regard to their linking activities and therefore do not provide decision makers with the reasons...
Modelling interstellar extinction and polarization with spheroidal grains
We calculate the wavelength dependence of the ratio of the linear polarization degree to extinction (polarizing efficiency) P(λ)/A(λ) from the ultraviolet to near-infrared. The prolate and oblate particles with aspect ratios from a/b = 1.1 up to 10 are assumed to be rotating and partially aligned with the mechanism of paramagnetic relaxation (Davis– Greenstein). Size/shape/orientation effects a...
متن کاملexistence and approximate $l^{p}$ and continuous solution of nonlinear integral equations of the hammerstein and volterra types
بسیاری از پدیده ها در جهان ما اساساً غیرخطی هستند، و توسط معادلات غیرخطی بیان شده اند. از آنجا که ظهور کامپیوترهای رقمی با عملکرد بالا، حل مسایل خطی را آسان تر می کند. با این حال، به طور کلی به دست آوردن جوابهای دقیق از مسایل غیرخطی دشوار است. روش عددی، به طور کلی محاسبه پیچیده مسایل غیرخطی را اداره می کند. با این حال، دادن نقاط به یک منحنی و به دست آوردن منحنی کامل که اغلب پرهزینه و ...
15 صفحه اولذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2021
ISSN: ['2041-8213', '2041-8205']
DOI: https://doi.org/10.3847/1538-4357/ac0050