Periodic Reporting for period 1 - AstroSsearch (The quest to understand interstellar sulfur and metal chemistry through synergetic laboratory and radio telescope observations)
Reporting period: 2021-10-01 to 2023-09-30
Astrochemistry is one of the scientific frontiers in which many intriguing open questions remain that directly and indirectly impact our lives, and thus, it garners significant attention. These open questions revolve around the origins of life and the complex chemistry occurring in astronomical systems, and the resulting research indirectly influences our lives through the innovation that occurs. We aimed to help understand the complex chemistry occurring the interstellar medium (ISM) by using electrical discharge sources with rotational spectroscopy to study sulfur and metal containing molecules and polycyclic aromatic hydrocarbons (PAHs). While there is evidence that these species exist in the ISM, especially molecules containing sulfur, astronomers have been unable to detect more complex species bearing sulfur and metals. It is possible that these species could be found on ice grains and not in the gas phase; however, they could then be released into the gas phase so that we can detect them with radio telescopes. Also, PAHs are thought to have been a source of sequestered carbon; however, until recently, direct evidence by the individual identification of a PAH had not been able to prove their existence. Then in 2021 indene was detected, followed by the detections of the substituted PAHs, cyano-naphthalene and cyano-indene were made. We now know that these PAHs exist in the ISM, but we do not know to what extent. Thus, our research aimed to help answer the questions: Where is sulfur being sequestered?, Why are we not detecting more and bigger sulfur containing species?, and What other species of PAHs can we detect?
We aimed to answer these questions through the following objectives. First, we implemented a discharge source and laser ablation in the existing broadband rotational spectrometer at the University of Valladolid to produce new sulfur/metal bearing species and PAHs. With rotational spectroscopy, we can generate accurate line lists and obtain rotational parameters that help guide astronomers in their searches for new molecular species. We then developed a controlled reactive chemistry source that enabled us to engineer chemical reactions so that we may explain the chemistry that is occurring in the formation of new molecular species. With this we provide a new tool not only for the astrochemistry community but also for the atmospheric chemistry community. Finally, we set out to detect these species in astronomical datasets through international collaborations using state-of-the-art astronomical surveys.
We aimed to answer these questions through the following objectives. First, we implemented a discharge source and laser ablation in the existing broadband rotational spectrometer at the University of Valladolid to produce new sulfur/metal bearing species and PAHs. With rotational spectroscopy, we can generate accurate line lists and obtain rotational parameters that help guide astronomers in their searches for new molecular species. We then developed a controlled reactive chemistry source that enabled us to engineer chemical reactions so that we may explain the chemistry that is occurring in the formation of new molecular species. With this we provide a new tool not only for the astrochemistry community but also for the atmospheric chemistry community. Finally, we set out to detect these species in astronomical datasets through international collaborations using state-of-the-art astronomical surveys.
The AstroSsearch project has been a very successful program which has resulted in three publications in peer-reviewed scientific journals so far, with more in progress. These publications have centered around understanding how non-covalent interactions would affect the interaction of biomolecules (molecules relevant for life) with ice grains and also the chemistry that could be producing naphthalene in the ISM. This project has established new collaborations between the University of Valladolid and astronomy groups, facilitating the ease of transfer of information between chemistry and astronomy groups. The results have also been disseminated at several international conferences.
The results from AstroSsearch go beyond the state-of-the-art and have facilitated a chemical understanding of reactions occurring in the ISM. During the course of this project, I implemented a DC electrical discharge nozzle and laser ablation source in the 2-8 GHz chirped-pulse Fourier transform microwave (CP-FTMW) spectrometer at the University of Valladolid. I also upgraded the instrument to operate over the 8-18 GHz frequency range so that the data that we produce can be directly overlapped with astronomical datasets that are generated at single dish telescopes, and I have introduced millimeter wave instrumentation that directly overlaps with interferometric telescopes to the lab. By doing so, our data has become more useful to the astronomy community, as we are able to cover a large frequency range and generate very accurate line lists with accurate rotational parameters. With all of this instrumentation, we have been able to acquire the discharge spectra of several systems of sulfur bearing species and PAHs, and by doing so, we have been able to generate the rotational spectra of more complex PAHs and sulfur bearing species. Working in close collaboration with astronomers, we have been able to search for species towards the dark molecular cloud TMC-1 using the QUIJOTE radio astronomy survey and towards Sagittarius B2 North with the Greenbank Telescope PRIMOS survey.
In conjunction to these efforts, I have developed a new controlled reactive chemistry source that has allowed me to explore the chemistry that is happening within these discharge experiments. This has helped me to directly probe the chemical reactions that could be occurring in the ISM by allowing me to monitor discharge experiments under different conditions than the traditional DC electrical discharge experiments. This new source will provide an unparalleled understanding into the reactions that could be occurring in the ISM.
The results from AstroSsearch go beyond the state-of-the-art and have facilitated a chemical understanding of reactions occurring in the ISM. During the course of this project, I implemented a DC electrical discharge nozzle and laser ablation source in the 2-8 GHz chirped-pulse Fourier transform microwave (CP-FTMW) spectrometer at the University of Valladolid. I also upgraded the instrument to operate over the 8-18 GHz frequency range so that the data that we produce can be directly overlapped with astronomical datasets that are generated at single dish telescopes, and I have introduced millimeter wave instrumentation that directly overlaps with interferometric telescopes to the lab. By doing so, our data has become more useful to the astronomy community, as we are able to cover a large frequency range and generate very accurate line lists with accurate rotational parameters. With all of this instrumentation, we have been able to acquire the discharge spectra of several systems of sulfur bearing species and PAHs, and by doing so, we have been able to generate the rotational spectra of more complex PAHs and sulfur bearing species. Working in close collaboration with astronomers, we have been able to search for species towards the dark molecular cloud TMC-1 using the QUIJOTE radio astronomy survey and towards Sagittarius B2 North with the Greenbank Telescope PRIMOS survey.
In conjunction to these efforts, I have developed a new controlled reactive chemistry source that has allowed me to explore the chemistry that is happening within these discharge experiments. This has helped me to directly probe the chemical reactions that could be occurring in the ISM by allowing me to monitor discharge experiments under different conditions than the traditional DC electrical discharge experiments. This new source will provide an unparalleled understanding into the reactions that could be occurring in the ISM.
The goals of AstroSsearch are multifaceted and seek to broaden the horizons of astrochemical research with new and innovative molecular sources in combination with the chirped-pulse microwave technique and mmw technology. These efforts have led to the following advancements in astrochemistry:
• Provide broadband rotationally resolved spectra of sulfur and metal-bearing species and polycyclic aromatic hydrocarbons (PAHs), species that have traditionally been under-represented, to the astrochemical community. Observations on these species will push forward our understanding of the chemical complexity of the ISM and lead to a more complete chemical inventory.
• Development of a novel controlled reactive chemistry source that will not only produce rotational spectra of unique species but allow the community to investigate chemical reactions pertinent to those occurring in the ISM. Other laboratories will be able to use this new design to help facilitate their understanding of their experiments.
• Interdisciplinary efforts for the detection of sulfur and metal-bearing species in the ISM using state-of-the-art facilities.
• Improved synergy between laboratory spectroscopy, observational astrochemistry, and theoretical astronomy.
The outcomes from this project will help advance our understanding of how life came to be on Earth through the spectroscopic data that is generated and fuel innovation that comes from pushing the boundaries of astronomy. As basic science has led to some of the greatest technological advances of this time (GPS and CAT scans), it is feasible that the need for deep averaged astronomical datasets can lead to further societal innovation while trying to access information from the cosmos. Also, the newly developed source will be important for atmospheric chemistry. By using this source, the atmospheric reactions between pollutants can be untangled, thus giving a better understanding of pollutants and their potential reactions.
• Provide broadband rotationally resolved spectra of sulfur and metal-bearing species and polycyclic aromatic hydrocarbons (PAHs), species that have traditionally been under-represented, to the astrochemical community. Observations on these species will push forward our understanding of the chemical complexity of the ISM and lead to a more complete chemical inventory.
• Development of a novel controlled reactive chemistry source that will not only produce rotational spectra of unique species but allow the community to investigate chemical reactions pertinent to those occurring in the ISM. Other laboratories will be able to use this new design to help facilitate their understanding of their experiments.
• Interdisciplinary efforts for the detection of sulfur and metal-bearing species in the ISM using state-of-the-art facilities.
• Improved synergy between laboratory spectroscopy, observational astrochemistry, and theoretical astronomy.
The outcomes from this project will help advance our understanding of how life came to be on Earth through the spectroscopic data that is generated and fuel innovation that comes from pushing the boundaries of astronomy. As basic science has led to some of the greatest technological advances of this time (GPS and CAT scans), it is feasible that the need for deep averaged astronomical datasets can lead to further societal innovation while trying to access information from the cosmos. Also, the newly developed source will be important for atmospheric chemistry. By using this source, the atmospheric reactions between pollutants can be untangled, thus giving a better understanding of pollutants and their potential reactions.