AN H{alpha} NUCLEAR SPIRAL STRUCTURE IN THE E0 ACTIVE GALAXY Arp 102B
- Instituto de Astrofisica de Canarias, 38200 La Laguna (Spain)
- Department of Physics, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623 (United States)
- Instituto de Fisica, UFRGS, Av. Bento Goncalves 9500, 91501-970 Porto Alegre RS (Brazil)
- INAF-Osservatorio Astrofisico di Arcetri, Largo Fermi 5, I-50125 Firenze (Italy)
- Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead, CH41 1LD (United Kingdom)
- INAF-Osservatorio Astronomico di Torino, Strada Osservatorio 20, 10025 Pino Torinese (Italy)
We report the discovery of a two-armed mini-spiral structure within the inner kiloparsec of the E0 LINER/Seyfert 1 galaxy Arp 102B. The arms are observed in H{alpha} emission and located east and west of the nucleus, extending up to {approx}1 kpc from it. We use narrow-band imaging from the Hubble Space Telescope Advanced Camera for Surveys, in combination with archival Very Large Array radio images at 3.6 and 6 cm to investigate the origin of the nuclear spiral. From the H{alpha} luminosity of the spiral, we obtain an ionized gas mass of the order of 10{sup 6} solar masses. One possibility is that the nuclear spiral represents a gas inflow triggered by a recent accretion event which has replenished the accretion disk, giving rise to the double-peaked emission-line profiles characteristic of Arp 102B. However, the radio images show a one-sided curved jet which correlates with the eastern spiral arm observed in the H{alpha} image. A published milliarcsecond radio image also shows a one-sided structure at position angle {approx}40{sup 0}, approximately aligned with the inner part of the eastern spiral arm. The absence of a radio counterpart to the western spiral arm is tentatively interpreted as indicating that the jet is relativistic, with an estimated speed of 0.45c. Estimates of the jet kinetic energy and the ionizing luminosity of the active nucleus indicate that both are capable of ionizing the gas along the spiral arms. We conclude that, although the gas in the nuclear region may have originated in an accretion event, the mini spiral is most likely the result of a jet-cloud interaction rather than an inflowing stream.
- OSTI ID:
- 21578287
- Journal Information:
- Astrophysical Journal, Vol. 736, Issue 2; Other Information: DOI: 10.1088/0004-637X/736/2/77; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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