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Updated: Dec 2, 2025
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Super-resolution Imaging of the Bacterial Division Machinery
Published on: January 21, 2013
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New molecular species at redshift z = 0.89
B Tercero1,2, J Cernicharo3, S Cuadrado3
1Observatorio Astronómico Nacional (OAN-IGN). Calle Alfonso XII, 3, E-28014 Madrid, Spain.
Astronomy and Astrophysics
|November 6, 2020
Summary
Astronomers detected new molecules, including methyl mercaptan (CH3SH) and propynyl cation (C3H+), in a distant galaxy at z=0.89. These findings offer insights into the chemical composition of early galaxies and interstellar cloud conditions.
Area of Science:
- Astrochemistry
- Extragalactic Astronomy
- Molecular Astrophysics
Background:
- The chemical complexity of the interstellar medium (ISM) in galaxies provides crucial insights into star formation and galactic evolution.
- Previous studies have identified a limited number of molecular species in extragalactic sources, particularly at high redshifts.
Purpose of the Study:
- To report the first extragalactic detections of specific molecules: methyl mercaptan (CH3SH), propynyl cation (C3H+), cyanoacetylene (C3N), formic acid (HCOOH), vinyl cyanide (CH2CHCN), and formaldimine (H2CN).
- To expand the inventory of known molecules in an early-universe galaxy, increasing the total identified species to 54.
- To characterize the physical conditions (rotational temperatures, column densities, and abundances) of these molecular species within the observed galaxy.
Main Methods:
- Utilizing the Yebes 40 m radio telescope for a spectral line survey in the Q band (58.7–93.5 GHz rest-frame frequencies).
- Observing the spiral arm of a galaxy at redshift z = 0.89, located along the line of sight to the quasar PKS 1830-211.
- Detecting molecules in absorption against the background quasar's continuum emission.
Main Results:
- Confirmed the first extragalactic detections of CH3SH, C3H+, C3N, HCOOH, CH2CHCN, and H2CN.
- Identified additional molecules: OCS, SO2, and NH2CN, bringing the total molecular species count to 54 (excluding isotopologues).
- Determined that the detected species are subthermally excited, with derived rotational temperatures and column densities.
Conclusions:
- The molecular abundances, particularly those of C3H+ and other cations, are indicative of diffuse or translucent interstellar clouds.
- The observed chemical composition suggests the presence of enhanced ultraviolet radiation fields or strong shock conditions within the galaxy's spiral arm.
- These findings contribute to understanding the chemical evolution of galaxies in the early universe.
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