An international team of scientists has successfully mapped the magnetic field of our galaxy, the Milky Way, using telescopes that observe the sky in the microwave range. The new research is published in Monthly Notices of the Royal Astronomical Society.
The team used the QUIJOTE (QUI JOint TEnerife) collaboration, located at the Teide Observatory in Tenerife in the Canary Islands. It comprises two telescopes with a diameter of 2.5 m, which observe the sky in the microwave part of the electromagnetic spectrum.
Led by the Instituto de Astrofísica de Canarias (IAC), the mapping began in 2012. Almost a decade later, the Collaboration presented a series of 6 scientific papers, providing the most accurate description to date of the polarization of the Milky Way’s emission. Mode at microwave wavelengths. Polarization is a property of transverse waves, such as light waves, that specifies the direction of wave oscillations and signifies the presence of a magnetic field.
The studies complement previous space missions dedicated to studying the cosmic microwave background (CMB) radiation, the fossil radiation left behind by the Big Bang that has provided detailed insight into the early history of the cosmos.
In addition to mapping the magnetic structure of the Milky Way, QUIJOTE data has also proven useful in other scenarios. The new data is also a unique tool for studying anomalous microwave emission (AME), a type of emission first detected 25 years ago. AME is thought to be produced by the rotation of very small dust particles in the interstellar medium, which tend to be oriented by the presence of the galactic magnetic field.
The new results allowed the team to obtain information about the structure of the magnetic field of the Milky Way, as well as help to understand the energy processes that took place close to the birth of the Universe. To measure the signals from that time, scientists must first remove the emission veil associated with our own galaxy. The new maps provided by QUIJOTE do just that, allowing us to better understand these elusive signals from the wider Universe.
The maps from QUIJOTE also enabled the study of a recently detected excess of microwave emission from the center of our galaxy. The origin of this emission is currently unknown, but it could be connected to the decay processes of dark matter particles. With QUIJOTE, the team confirmed the existence of this excess radiation and found some evidence that it could be polarized.
Finally, the new maps from QUIJOTE enabled the systematic study of more than 700 sources of radio and microwave emission, both of galactic and extragalactic origin, meaning the data is helping scientists decipher signals coming from beyond of our galaxy, including cosmic microwaves. background radiation.
“These new maps provide a detailed description in a new frequency range, from 10 to 40 GHz, complementing those from space missions such as Planck and WMAP,” comments José Alberto Rubiño, principal scientist of the QUIJOTE Collaboration. “We have characterized the synchrotron emission from our galaxy with unprecedented accuracy. This radiation is the result of the emission of charged particles traveling at near-light speeds in the galactic magnetic field. These maps, the result of nearly 9,000 hours of observation. , are a unique tool for studying magnetism in the universe,” he adds.
“One of the most interesting results we found is that the polarized synchrotron emission from our galaxy is much more variable than previously thought,” comments Elena de la Hoz, researcher at the Instituto de Física de Cantabria (IFCA). “The results we obtained are a reference to help future experiments make reliable detections of the CMB signal,” she adds.
“Scientific evidence suggests that the Universe went through a phase of rapid expansion, called inflation, a fraction of a second after the Big Bang. If this is correct, we would expect to find some observable consequences when studying cosmic microwave polarization. Measuring those expected features is difficult, because they are small in amplitude, but also because they are less bright than the polarized emission from our own galaxy.” notes Rubiño, “However, if we eventually measure them, we will have information indirectly about physical conditions in the early stages of our Universe, when energy scales were much larger than those we can access or study from the ground. has enormous implications for our understanding of fundamental physics.”
“The QUIJOTE maps also allowed the study of microwave emissions from the center of our galaxy. An excess of microwave emission from this region has recently been detected, the origin of which is unknown, but whose origin could be connected to the decay processes of dark matter particles. With QUIJOTE we confirmed the existence of this excess radiation and found some evidence that it could be polarized”, comments Federica Guidi, researcher at the Institut d’Astrophysique de Paris (IAP, Francia).
The paper appears in “Quijote scientific results—IV. A survey of the northern sky in intensity and polarization at 10–20 GHz with the Multi-Frequency Instrument,” Rubiño-Martin et al., published in Monthly Notices of the Royal Astronomical Society.
JA Rubiño-Martín et al., Scientific results QUIJOTE—IV. A survey of the northern sky in intensity and polarization at 10–20 GHz with the multi-frequency instrument, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stac3439
D Herranz et al, Scientific results QUIJOTE—IX. The radio sources from the QUIJOTE-MFI wide survey maps, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stac3657
D Tramonte et al, QUIJOTE scientific results—V. Microwave intensity and polarization spectra of the galactic regions W49, W51 and IC443, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stac3502
F Guidi et al, QUIJOTE scientific results—VI. The Haze seen by QUIJOTE, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stac3468
F Poidevin et al, QUIJOTE scientific results—VII. The Northern Hemisphere QUIJOTE-MFI survey of Galactic AME sources, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stac3151
E from Hoz et al, QUIJOTE Scientific results—VIII. Diffuse polarized close-ups from component separation with QUIJOTE-MFI, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stac3020
Provided by the Royal Astronomical Society
Citation: Astronomers Create New Microwave Map of Milky Way and Beyond (2023 January 12) Retrieved January 12, 2023 from https://phys.org/news/2023-01-astronomers-microwave-milky.html
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