The 15-metre (~49 ft) James Clerk Maxwell Telescope (JCMT) at the East Asian Observatory (EAO) near the summit of Maunakea, Hawaii, is the world’s largest telescope designed to operate only in the submillimetre wavelength range. In 2018, Molokai’i High School graduate Mallory Goh spent time with JCMT through the Maunakea Scholars Program. EAO astronomer Dr. With the help of Harriet Parsons, Guo obtained unique images of the Horsehead Nebula in polarized light that reveal the nebula’s magnetic fields.

Guo (currently a graduate student at Brown University) presented the images as part of a science fair representing Molokai High School. A year later, a team of astronomers from the Korea Institute of Astronomy and Space Sciences (KASI), the University of Science and Technology (UST), and the University of London (UCL) used these observations to quantitatively analyze the strength and role of magnetic fields. used. area. A paper describing the observations and analysis, “Magnetic Fields in the Horsehead Nebula,” was recently published. Astronomy Journal .

The 2018 observations were made with the JCMT POL-2 instrument, a linear polarimeter that collects polarization data with the submillimeter Common User Bolometer Array 2 (SCUBA-2) instrument. Together, these instruments measure how magnetic fields in space affect the alignment of interstellar dust.

Dr. As Parsons explained in an EAO press release, “You can think of the POL-2 as a polarized sunglasses standing in front of a telescope. In Hawaii, most of us are used to wearing polarized sunglasses—they help us see better by reducing glare—but in a telescope, by rotating polarized lenses, we analyze the brightness of the observed light and see if it is affected by magnetic fields. . With such instruments, astronomers can observe clouds of gas and dust both in our own galaxy and beyond, expanding our understanding of what shapes them.”

Astronomers from KASI, UST and UCL obtained additional data using JCMT’s other operational tools, the Heterodyne Array Reception Program (HARP) and Automatic Spectral Imaging System Correlation (ACSIS), to measure how bright and dense the region is. HARP device, oxygen-18 (C ¹⁸ O), a stable isotope of oxygen believed to originate from molecular clouds.

“The data is impressive, and what it tells us is even more impressive. “I’m delighted Mallory has given us the opportunity to study such a beautiful and iconic region,” said UCL astronomer Dr. Kate Pattle, one of the study’s co-authors, and what we found is the Horsehead Nebula. “These observations tell us the story of two dense regions hidden in Horsehead. We see a cloud of hot gas and dust… the head and mane of a horse interacting with ultraviolet photons from nearby bright young stars.”

The JCMT instruments allowed the team to observe interactions between the nebula’s “head” and “mane” and nearby young stars—interactions that appear to have a noticeable effect on the nebula’s magnetic field. The team hypothesized that the Horsehead Nebula formed when the Horsehead Nebula formed and collapsed along the observatory’s line of sight. Behind this ridge, they observed a cold dense clump of material that appears to be shielded from these interactions, which they suspect will form a new star system.

This made the observations particularly exciting because it allowed astronomers to see for the first time what magnetic field lines do in regions like the Horsehead Nebula. As Pettle adds, “This gives us important insight into how stars can continue to form even in regions like Horsehead, where the cold gas that provides material for new stars is washed away by photons from nearby young, hot stars. “We’re waiting for this to happen, and so looking at how stars form in the Horsehead Nebula can give us insight into the history of our own solar system.”

Despite being an iconic astronomical object, Guo’s observations were the first attempt to visualize its magnetic field. “I was so excited when I heard about the Maunakea Scholars program,” Goh said. “I thought it was a great opportunity to use the telescopes on Maunakea. I decided to study the Horsehead Nebula because I thought it was beautiful and couldn’t find much research on it.”