Observations of the dwarf galaxy Markarian 71 with infrared and optical telescopes solve a problem in infrared astronomy and enable better measurements of the structure of galaxies and interstellar dust clouds. Composite image of Markarian 71 from the Hubble Space Telescope. Credit: Hubble Space Telescope/NASA
A problem that has afflicted astronomers operating in the infrared has been solved through a research study making use of data from both terrestrial and sky-based telescopes. The findings, which were published in Nature Astronomy on April 20, might help in the production of more exact observations relating to the composition of the universe using instruments such as the James Webb Space Telescope.
” Were trying to determine the composition of gases inside galaxies,” stated Yuguang Chen, a postdoctoral scientist dealing with Professor Tucker Jones in the Department of Physics and Astronomy at the University of California, Davis.
Most of elements apart from hydrogen, helium, and lithium are formed inside stars. As an outcome, astronomers can comprehend the number of and what type of stars are being formed in a far-off things by studying the structure and distribution of heavier elements, particularly the ratio of oxygen to hydrogen.
Composite image of Markarian 71 from the Hubble Space Telescope. Credit: Hubble Space Telescope/NASA
By flying at 38,000 to 45,000 feet, the aircraft could get above 99% of the water vapor in Earths atmosphere, which efficiently obstructs infrared light from deep area from reaching ground level. A joint task of NASA and the German space agency, SOFIA made its last functional flight in September 2022 and is now headed for a museum screen in Tucson.
SOFIA was collectively run by the Universities Space Research Association, Inc., and the Deutsches SOFIA Institut.
Astronomers use two approaches to measure oxygen in a galaxy, however sadly, they offer various outcomes. One common approach, collisionally excited lines, gives a strong signal, however the results are believed to be sensitive to temperature modifications, Chen stated. A 2nd method utilizes a different set of lines, called recombination lines, which are fainter but not believed to be impacted by temperature level.
The recombination line technique consistently produces measurements about double those from collisionally ecstatic lines. Researchers attribute the disparity to temperature fluctuations in gas clouds, but this has not been directly proven, Chen stated.
Chen, Jones, and coworkers used infrared and optical astronomy to determine oxygen abundance in dwarf galaxy Markarian 71, about 11 million light-years from Earth. They utilized archived data from the just recently retired SOFIA flying telescope and the retired Herschel Space Observatory, in addition to making observations with telescopes at the W.M. Keck Observatory in Mauna Kea, Hawaii.
SOFIA (Stratospheric Observatory For Infrared Astronomy) was a telescope mounted in a Boeing 747 airplane. By flying at 38,000 to 45,000 feet, the airplane might get above 99% of the water vapor in Earths environment, which successfully blocks infrared light from deep space from reaching ground level. A joint job of NASA and the German area firm, SOFIA made its last functional flight in September 2022 and is now headed for a museum display screen in Tucson.
The Herschel Space Observatory, named after astronomers William and Caroline Herschel, was an infrared space telescope run by the European Space Agency. It was active from 2009 to 2013.
A surprising outcome
With information from these instruments, Chen and Jones analyzed oxygen abundance in Markarian 71 while correcting for temperature fluctuations. They discovered that the result from collisionally excited infrared lines was still 50% less than that from the recombination line approach, even after removing the impact of temperature level.
” This outcome is very unexpected to us,” Chen said. There is no consensus on an explanation for the inconsistency, he said. The team prepares to take a look at additional items to find out what properties of galaxies correlate with this variation, Chen stated.
One of the objectives of the James Webb Space Telescope, released in 2022, is to make infrared observations of the structure of distant galaxies in the very first billion years of deep space. The new results supply a framework for making these measurements with the JWST and the Atacama Large Millimeter Array in Chile.
Reference: “Accurate oxygen abundance of interstellar gas in Mrk 71 from optical and infrared spectra” by Yuguang Chen, Tucker Jones, Ryan Sanders, Dario Fadda, Jessica Sutter, Robert Minchin, Erin Huntzinger, Peter Senchyna, Daniel Stark, Justin Spilker, Benjamin Weiner and Guido Roberts-Borsani, 20 April 2023, Nature Astronomy.DOI: 10.1038/ s41550-023-01953-7.
Extra co-authors on the paper are: Ryan Sanders and Erin Huntzinger, UC Davis; Dario Fadder, Jessica Sutter, and Robert Minchin, SOFIA Science Center, NASA Ames Research Center; Peter Senchyna, Observatories of the Carnegie Institute for Science, Pasadena; Daniel Stark and Benjamin Weiner, Steward Observatory, University of Arizona; Justin Spilker, Texas A&M University; and Guido Roberts-Borsani, UCLA. The work was economically supported in part by NASA. SOFIA was jointly operated by the Universities Space Research Association, Inc., and the Deutsches SOFIA Institut.
The W.M. Keck Observatory is run as a scientific collaboration amongst the California Institute of Technology, the University of California, and NASA, with financial backing from the W.M. Keck Foundation. The scientists would like to thank the Hawaiian neighborhood for the privilege of enabling them to conduct observations on Mauna Kea, which plays a substantial cultural and religious function.
