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Title: Enormous H I envelope around a Seyfert galaxy

Journal Article · · Astrophys. J., Lett. Ed.; (United States)
DOI:https://doi.org/10.1086/183245· OSTI ID:5155348

The Type 2 Seyfert galaxy Mrk 348 has been mapped at 21 cm using the Arecibo radio telescope. Emission from H I is extended over an 8' x 2' region (approx.200 x 300 kpc if H/sub 0/=55 km s/sup -1/ Mpc/sup -1/) which is an order of magnitude larger than the Holmberg diameter of the nearly face-on galaxy. The velocity field in the H I envelope indicates a rising rotation curve out to at least 100 kpc, but because of the small and unknown inclination angle of Mrk 348, the velocity field is difficult to interpret. Near the central galaxy, the isovelocity contours deviate from those expected if the H I is simply undergoing circular motion in a plane. Three explanations are considered for this, including warping of the plane, gas flow in a giant bar, and radial inflow.

Research Organization:
Astronomy Department, Columbia University, New York, NY 10027
OSTI ID:
5155348
Journal Information:
Astrophys. J., Lett. Ed.; (United States), Vol. 238:1
Country of Publication:
United States
Language:
English