SKA studies of in situ synchrotron radiation from molecular clouds

Abstract

Observations of the properties of dense molecular clouds are critical in understanding the process of star-formation. One of the most important, but least understood, is the role of the magnetic fields. We discuss the possibility of using high-resolution, high-sensitivity radio observations with the SKA to measure for the first time the in-situ synchrotron radiation from these molecular clouds. If the cosmic-ray (CR) particles penetrate clouds as expected, then we can measure the B-field strength directly using radio data. So far, this signature has never been detected from the collapsing clouds themselves and would be a unique probe of the magnetic field. Dense cores are typically ∼ 0.05 pc in size, corresponding to ∼arcsec at ∼kpc distances, and flux density estimates are ∼ mJy at 1 GHz. The SKA should be able to readily detect directly, for the first time, along lines-of-sight that are not contaminated by thermal emission or complex foreground/background synchrotron emission. Polarised synchrotron may also be detectable providing additional information about the regular/turbulent fields.Advancing Astrophysics with the Square Kilometre Array

Magnetism Science with the Square Kilometre Array

“…In Canada, the Canadian Initiative for Radio Astronomy Data Analysis (CIRADA) 15 is producing enhanced and science-ready data products for polarization from POSSUM, VLASS, and CHIME, and is also acting as a pilot study for an anticipated Canadian SRC. In South Africa, the Inter-University Institute for Data Intensive Astronomy 16 , in partnership with several South African institutions, has established a data intensive research cloud 17 prototyping SRC technologies, as well as processing and analytics tools for SKA pathfinder Large Survey Programs on MeerKAT and the upgraded GMRT.…”

“…An overview of chapters within the field of cosmic magnetism, as well as a description of the headline magnetism "Rotation Measure (RM) Grid" survey were provided [5]. The overview chapter was supplemented with additional detailed contributions in the areas of active galactic nuclei and radio galaxies [6][7][8][9], nearby galaxies [10,11], galaxy clusters [12][13][14], the Milky Way [15,16], the interstellar medium (ISM) and star formation [17,18], large-scale structure and the cosmic web [19,20], dark matter [21], and advanced techniques [22][23][24].…”

Resolving 4-D Nature of Magnetism with Depolarization and Faraday Tomography: Japanese SKA Cosmic Magnetism Science

“…We need to measure magnetic fields in HII regions using dense RM grids. Related SKA Science Book 2015 Chapters; Han et al (2015), Haverkorn et al (2015), Dickinson et al (2015), Robishaw et al (2015).…”

Using SKA Rotation Measures to Reveal the Mysteries of the Magnetised Universe

“…Investigating these relations both within the Milky Way and nearby galaxies is crucial to understanding the role of magnetic fields in the structure formation of the molecular interstellar medium (ISM), and in particular, the formation of giant molecular clouds that are the cradles of massive star formation. Observations of the in-situ synchrotron radiation emitted by dense molecular clouds is also a possibility with SKA (Dickinson et al 2015) and imaging the polarised emission from such clouds will provide constraints on the internal magnetic fields and their distribution in these clouds, which will be crucial to addressing questions regarding the effect of magnetic fields in star formation.…”

“…For further information see the following chapters in the 2015 SKA Science Case: Dickinson et al (2015); Haverkorn et al (2015).…”