Matsya Purana 193.87

193.87

aśvamedhamavāpnoti daivataiḥ saha modate.
tatra siddhiṃ parāṃ prāpto bhṛgustu munipuṅgavaḥ.
avatāraḥ kṛtastatra śaṅkareṇa mahātmanā .. 193.88

A group of tîrthas lie near Bhṛigu tîrtha where one should bathe with or without motive. By bathing there one gets the benefits of performing Aśvamedha sacrifice and then goes and enjoys in the company of the Devas. Lord Śiva assumed His form there when the sage Bhṛigu attained his siddhi.—87-88