2014/11/03 by Yacine Ali-Haïmoud, Laura Pérez, Laura M. Pérez +4 · 17 citations
Chemistry · Earth and Planetary Sciences · Physics and Astronomy · #Astrobiology #Astrochemistry #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #Galaxy #Green Bank Telescope #Infrared #Interstellar medium #Molecular Spectroscopy and Structure #Molecular cloud #Physics #Polycyclic aromatic hydrocarbon #Population #Spectral line #Stars #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stu2476
published in Monthly Notices of the Royal Astronomical Society 447(1), 315-324 (Oxford University Press) · 11 pages, 11 figures
arxiv created 2014/11/03 · openalex publication_date 2014/12/15 · arxiv updated 2015/08/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Polycyclic aromatic hydrocarbons (PAHs) are believed to be the small-size tail of the interstellar carbonaceous dust grain population. Their vibrational emission is the most widely accepted source of the aromatic near-infrared features, and their rotational radiation is a likely explanation for the dust-correlated anomalous microwave emission (AME). Yet, no individual interstellar PAH molecule has been identified to date. It was recently recognized that quasi-symmetric planar PAHs ought to have a well identifiable comb-like rotational spectrum, and suggested to search for them in spectroscopic data with matched-filtering techniques. We report the results of the first such search, carried out with the Green Bank Telescope, and targeting the star-forming region IC 348 in the Perseus molecular cloud, a known source of AME. Our observations amounted to 16.75 h and spanned a 3-GHz-wide band extending from 23.3 to 26.3 GHz. Using frequency switching, we achieved a sensitivity of 0.4 mJy per 0.4 MHz channel (1σ). The non-detection of comb-like spectra allowed us to set upper bounds on the abundance of specific quasi-symmetric PAH molecules (specified uniquely by their moments of inertia) of approximately 0.1 per cent of the total PAH abundance. This bound generically applies to PAHs with approximately 15–100 carbon atoms.