Physics of Dust Grain Alignment

It is known that dust grains in the interstellar medium (ISM) align with magnetic fields, which causes the light of background stars to become polarized. The alignment physics of these particles is still somewhat unclear. Our group uses observational data along with Radiative Alignment Torque (RAT) theory to put further constraints on the physics behind this alignment.

Student Involvement

Each year several undergraduate physics students from SCU work with B-G Andersson , myself and other collaborators on this project at NASA Ames Research Center. Students have worked on an array of projects as described below.

This work is currently funded by a three-year NSF grant that myself and collaborators received in 2017 (Title: "Collaborative Research: Using Observations and Models to Study How Dust Grains Between the Stars Align"; Award Number 1715060). In addition, funding has been provided by the SCU Physics Department Fox Fellowships.

  • 2021: Sophia Flores and Weston Tierney; Continuuing students - Sydney Fox-Middleton, Connery Chen and Joshua Yaldaei
    Sophia examined the magentic field geometery in the Orion Bar using HAWC+ far-infrared data in order to better understand the transition from B-RAT to k-RAT alignment for dust grains in the ISM. Weston studied polarization data from stars in and near the OB3 super bubble in order to probe how intense UV radiation in the area from the O and B spectral-type stars may affect polarization. Sydney, Connery and Joshua all continued with projects related to their past summer's work.
  • 2020: Sydney Fox-Middleton, Connery Chen and Joshua Yaldaei
    Sydney utilized HAWC+ polarimetry data of the oxygen rich AGB star IK Tau to examine how grain mineralogy could affect grain alignment. Connery's research focused on the theorectical aspect of RAT. He used the RAT alignment code by Hoang et al. to understand how different observational data sets could be analyzed by varying different model parameters. Joshua examined GMRT+WSRT+DRAO high-resolution H I mapping of IC 63. His project leveraged our previous anlaysis of [CII] to study the transition of geometry and gas flow between ionized gas ([CII]) and neutral gas (HI).
  • 2019: Janik Karoly, Remy Dennis, and Maddie Dilg
    Janik examined the magnetic fields in the starless core L183 by using submm JCMT polarization observations. Remy examined the kinematics of the IC59 nebula using SOFIA/GREAT [CII] observations. Maddie reduced and analyzed optical spectropolarimetric data from Lick observatory to better understand grain alignment efficiency versus extinction.
  • 2018: Miranda Caputo and Ricky Spolzino
    Miranda used optical polarimetry of examine the grain characteristics and alignment in the circumstellar envelopes around AGB stars. Ricky used optical polarimetry to probe the radiation field color around the Per OB3 super bubble.
  • 2017: Shivam Desai and Morgan Gillis
    Shivam worked to reduce ice line spectra, also in the L183 cloud, with the goal to test the idea of whether ice formation enhances grain growth. Morgan used SOFIA/GREAT data to analyze the [C II] emission from the photodissociation region IC 63.
  • 2016: Ilija Medan
    Ilija studyied how local radiation fields contributed to grain alignment in the Local Bubble. His work has now been published in ApJ (see below).
  • 2015: Sarah Youlton
    Sarah worked on Keck/MOSFIRE data on the L183 cloud, primarily doing spectral classification of highly obscured stars to obtain accurate AV values.

Refereed Papers

Below are papers from summer student research projects.

    2020:

  • Janik Karoly, Archana Soam, B-G Andersson, Simon Coudé, Pierre Bastien, John E. Vaillancourt, Chang Won Lee; Revisiting the Magnetic Field of the L183 Starless Core, The Astrophysical Journal, Volume 900, Issue 2, id.181, 11 pp.
  • Miranda Caputo, Remy Dennis, B-G Andersson, Archana Soam, Ed Chambers, Rolf Gusten, Lewis B.G. Knee, Jurgen Stutzki; Physics and Chemistry of Radiation Driven Cloud Evolution. [C II] Kinematics of IC 59 and IC 63, submitted to ApJ

    • 2019:

  • Ilija Medan and B-G Andersson; Magnetic Field Strengths and Variations in Grain Alignment in the Local Bubble Wall, 2019, ApJ 873, 87

Research Group Image Gallery

Please click here to see some photos from our research group.

×
×