Distribution of blue galaxies in a merging cluster of galaxies Abell 168

Akihiko Tomita, Fumitaka E. Nakamura, Tadafumi Takata, Kouichirou Nakanishi, Tsutomu Takeuchi, Kouji Ohta, Toru Yamada

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


The fraction of star-forming galaxies in rich clusters of galaxies increases rapidly with the redshift. This is interpreted as the result of a rapid evolution of cluster galaxies, though its mechanism is not yet clear. One hypothesis is that if galaxies run into the dense intracluster medium (ICM) regions, starbursts can be induced due to the compression of molecular clouds in the galaxies by a raised "external" ICM pressure. In a merging cluster, there would be dense ICM regions and some galaxies may experience a rapid increase of external pressure. Thus, if the mechanism works, starbursts would occur in such galaxies. Such a situation is considered to be realized in Coma cluster, and galaxies showing a recent starburst have a characteristic spatial distribution; they populate an elongated region between two subclusters. We examined the above hypothesis by measuring the spatial distribution of blue galaxies, regarded as star-forming galaxies in Abell 168 to check whether a case like Coma is realized in this recently merging cluster. However, we could not find an enhanced blue-galaxy distribution between two subclusters. We discuss the causes of our result, including the possibilities of surviving the hypothesis.

Original languageEnglish
Pages (from-to)42-52
Number of pages11
JournalAstronomical Journal
Issue number1
Publication statusPublished - 1996 Jan
Externally publishedYes

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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