In search of magnetic fields in active galaxies with the flying telescope SOFIA/NASA
Enrique Lopez-Rodriguez Ph.D, Instrument Scientist (HAWC+)
Stratospheric Observatory for Infrared Astronomy, NASA Ames Research Centre
Time & Place
Fri, 29 Jun 2018 11:00:00 NZST in WEST 531
All are welcome
Galaxies are known to be composed by stars, their remnants, interstellar gas, dust and dark matter. Some galaxies host massive regions of star formation and/or active super massive black holes on their cores, commonly known as starburst galaxies and active galactic nuclei (AGN), respectively. The activity produced by massive star formations and energy released by accretion onto a supper massive black hole are typical subjects of study to understand how stars form, how galaxies evolve, and find relationships between them and their host galaxies.
Dust is a ubiquitous feature in both star formation regions and AGN. Dust absorbs radiation at all wavelengths and re-emit it in the infrared, peaking at ~100 microns for star formation and ~30 microns for AGN. In both cases, gravitational forces are present, although magnetic field have been proven to be key in the formation of stars as well as in the dusty outflows of AGN. However, magnetic field are notoriously difficult to observe. Polarimetric techniques provide a crucial approach to characterize magnetic fields in these astrophysical environments.
The Stratospheric Observatory For Infrared Astronomy (SOFIA) with its newest instrument HAWC+ has opened a new window to explore the role of magnetic fields in starburst galaxies and AGN in the range of 50-300 microns. SOFIA has a 2.5-m telescope onboard a Boeing 747 flying at 45,000ft, which avoids ~95% of the water vapour in the atmosphere. In this talk, I will present SOFIA, and newly obtained 50-200 microns imaging polarimetric observations of a starburst, M82, and an AGN, NGC 1068. In both cases, we have found a large-scale magnetic field structure dominated by star formation regions in M82, and by a galactic magnetic field in NGC 1068. We will also present the first 50-100 microns imaging polarimetric observations of a radio-loud AGN, Cygnus A. We have found a highly polarized (~10%) core dominated by dust emission in the 10-100 microns wavelength range, while the mm wavelength range is dominated by synchrotron emission.