Interplay of Magnetic Fields, Dust Extinction, and Grain Alignment in Three Molecular Clouds
7 affiliations
- 1Assam University
- 2Ramkrishna Nagar College
- 3Karimganj College
- 4Aryabhatta Research Institute of Observational Sciences
- 5Gauhati University
- 6Department of Physics
- 7Gurucharan University
Abstract
We present a multiwavelength study of three molecular clouds, L1346, L1388, and L1598, combining R -band polarimetric and archival photometric data to investigate their magnetic field morphology, physical characteristics, and dust grain alignment properties. Using a Near Infrared Photometric Technique, we estimate distances of 687 ± 26 pc (L1346), 414 ± 42 pc (L1388), and 642 ± 34 pc (L1598). Extinction mapping via the PNICER approach yields mean visual extinctions of 1.7, 1.4, and 2.0 mag, corresponding to column densities of 1.61, 1.33, and 1.92 × 10 ²¹ cm ⁻² . Complementary Herschel SPIRE observations provide mean dust temperatures of 13.35 K (L1346) and 14.48 K (L1598), with clump masses of ∼16 M ⊙ and ∼11 M ⊙ . The virial parameter of L1598 ( α vir = 0.86–1.04) confirms it as a gravitationally bound structure. Polarimetric observations, primarily probing the envelope regions, reveal mean polarization degrees of 4.46% (L1346), 3.34% (L1388), and 2.64% (L1598), with polarization angles closely aligned with the Galactic plane. Unlike L1598, the optical polarization vectors in L1346 and L1388 qualitatively agree with the large-scale Planck magnetic-field morphology. Applying the classical Davis-Chandrasekhar-Fermi (DCF) method, we derive approximate plane-of-sky (POS) magnetic field strength of ≈73 μ G (L1346), ≈17 μ G (L1388), and ≈23 μ G (L1598). A monotonic decrease in polarization rate with distance and a declining polarization efficiency with increasing extinction are observed in L1346 and L1388. Critical grain sizes of ≈0.069–0.102 μ m across L1346 and L1388, smaller than typical diffuse interstellar medium (ISM) values, indicate that alignment may be constrained by radiation field attenuation within the clouds. Taken together, these findings are compatible with the radiative torque alignment (RAT-A) theory.
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BibTeX
@article{mazumdar2026interplay,
title = {{Interplay of Magnetic Fields, Dust Extinction, and Grain Alignment in Three Molecular Clouds}},
author = {Sanchali Nath Mazumdar and Himadri Sekhar Das and Biki Prasad and Boinao Meikam and Dipankar Paul and Rajat Subhra Paul and Jeewan C. Pandey and Biman J. Medhi and Gulafsha B. Choudhury and Bhaskarjyoti Barman and Nambram Niroda Devi and Monoswini Chakravorty and Abinash Suklabaidya and Bhaskar Goswami},
journal = {The Astrophysical Journal},
year = {2026},
month = sep,
doi = {10.3847/1538-4357/ae9f42},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/ae9f42},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Interplay of Magnetic Fields, Dust Extinction, and Grain Alignment in Three Molecular Clouds
AU - Sanchali Nath Mazumdar
AU - Himadri Sekhar Das
AU - Biki Prasad
AU - Boinao Meikam
AU - Dipankar Paul
AU - Rajat Subhra Paul
AU - Jeewan C. Pandey
AU - Biman J. Medhi
AU - Gulafsha B. Choudhury
AU - Bhaskarjyoti Barman
AU - Nambram Niroda Devi
AU - Monoswini Chakravorty
AU - Abinash Suklabaidya
AU - Bhaskar Goswami
PY - 2026
DA - 2026/09/30
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/ae9f42
UR - https://iopscience.iop.org/article/10.3847/1538-4357/ae9f42
AB - We present a multiwavelength study of three molecular clouds, L1346, L1388, and L1598, combining R -band polarimetric and archival photometric data to investigate their magnetic field morphology, physical characteristics, and dust grain alignment properties. Using a Near Infrared Photometric Technique, we estimate distances of 687 ± 26 pc (L1346), 414 ± 42 pc (L1388), and 642 ± 34 pc (L1598). Extinction mapping via the PNICER approach yields mean visual extinctions of 1.7, 1.4, and 2.0 mag, corresponding to column densities of 1.61, 1.33, and 1.92 × 10 ²¹ cm ⁻² . Complementary Herschel SPIRE observations provide mean dust temperatures of 13.35 K (L1346) and 14.48 K (L1598), with clump masses of ∼16 M ⊙ and ∼11 M ⊙ . The virial parameter of L1598 ( α vir = 0.86–1.04) confirms it as a gravitationally bound structure. Polarimetric observations, primarily probing the envelope regions, reveal mean polarization degrees of 4.46% (L1346), 3.34% (L1388), and 2.64% (L1598), with polarization angles closely aligned with the Galactic plane. Unlike L1598, the optical polarization vectors in L1346 and L1388 qualitatively agree with the large-scale Planck magnetic-field morphology. Applying the classical Davis-Chandrasekhar-Fermi (DCF) method, we derive approximate plane-of-sky (POS) magnetic field strength of ≈73 μ G (L1346), ≈17 μ G (L1388), and ≈23 μ G (L1598). A monotonic decrease in polarization rate with distance and a declining polarization efficiency with increasing extinction are observed in L1346 and L1388. Critical grain sizes of ≈0.069–0.102 μ m across L1346 and L1388, smaller than typical diffuse interstellar medium (ISM) values, indicate that alignment may be constrained by radiation field attenuation within the clouds. Taken together, these findings are compatible with the radiative torque alignment (RAT-A) theory.
SN - 0004-637X
SN - 1538-4357
ER -