The manifestation of Lord Shiva in a column of fire in front of Brahma and Vishnu and carved in stone, is known as the Lingodbhavamurti manifestation of Lord Shiva. It is always enshrined in the rear niche of the sanctum enshrining a Shiva Lingam. Since most temples face east, the Lingodbhava faces west.
The non-anthromorphic form of the Shiva Lingam is a representation of the infinite cosmic column of fire, whose origins could not be traced by Brahma or Vishnu. This representation of the Shiva Lingam is the centre of reverence and worship in all Saivite temples.
On the night of Mahashivaratri the Lingodbhavamurti is bathed and anointed in the ritual of abhishekam and puja. This ritual conducted on the night of Mahashivaratri represents the worship of sacred Arunachala itself, (which is considered to be the manifestation of this cosmic column of effulgence) as it represents the primordial element of fire (Agni); one of the Pancha Bhuta Sthalams.
For more information about the significance of this worship, please visit an earlier posting at this link here.
