Searching for the Precursors of Life in External Galaxies

Details Searching for the Precursors of Life in External Galaxies Searching for the Precursors of Life in External Galaxies

2007-11-08

arxiv.org/abs/0711.1372v1

Astronomy and Astrophysics

Astrophysics

6 pages, 2 figures

Scientific paper

Are the organic molecules crucial for life on Earth abundant in early-epoch galaxies? To address this, we searched for organic molecules in extragalactic sources via their absorption features, known as diffuse interstellar bands (DIBs). There is strong evidence that DIBs are associated with polycyclic aromatic hydrocarbons (PAHs) and carbon chains. Galaxies with a preponderance of DIBs may be the most likely places in which to expect life. We use the method of quasar absorption lines to probe intervening early-epoch galaxies for the DIBs. We present the equivalent width measurements of DIBs in one neutral hydrogen (HI) abundant galaxy and limits for five DIB bands in six other HI-rich galaxies (damped Lyman-alpha systems--DLAs). Our results reveal that HI-rich galaxies are dust poor and have significantly lower reddening than known DIB-rich Milky Way environments. We find that DIBs in HI-rich galaxies do not show the same correlation with hydrogen abundance as observed in the Milky Way; the extragalactic DIBs are underabundant by as much as 10 times. The lower limit gas-to-dust ratios of four of the HI-rich early epoch galaxies are much higher than the gas-to-dust ratios found in the Milky Way. Our results suggest that the organic molecules responsible for the DIBs are underabundant in HI-rich early epoch galaxies relative to the Milky Way.

Affiliated with

Also associated with

No associations

Rating

Searching for the Precursors of Life in External Galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Searching for the Precursors of Life in External Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Searching for the Precursors of Life in External Galaxies will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-701702