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Post Info TOPIC: Polar-ring galaxy


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RE: Polar-ring galaxy
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Title: The polar ring galaxy AM1934-563 revisited
Authors: N. Brosch (1,2), A. Kniazev (2,3), D. Buckley (2), D. O'Donoghue (2), Y. Hashimoto (2), N. Loaring (2), E. Romero (2), M. Still (2), P. Vaisanen (2), E.B. Burgh (4), K. Nordsieck (4) ((1) Wise Observatory, Israel; (2) SAAO, South Africa; (3) SAO, Russia; (4) University of Wisconsin; USA)

We report long-slit spectroscopic observations of the dust-lane polar-ring galaxy AM1934-563 obtained with the Southern African Large Telescope (SALT) during its performance-verification phase. The observations target the spectral region of the Ha, [NII] and [SII] emission-lines, but show also deep NaI stellar absorption lines that we interpret as produced by stars in the galaxy. We derive rotation curves along the major axis of the galaxy that extend out to about 8 kpc from the centre for both the gaseous and the stellar components, using the emission and absorption lines. We derive similar rotation curves along the major axis of the polar ring and point out differences between these and the ones of the main galaxy. We identify a small diffuse object visible only in Ha emission and with a low velocity dispersion as a dwarf HII galaxy and argue that it is probably metal-poor. Its velocity indicates that it is a fourth member of the galaxy group in which AM1934-563 belongs. We discuss the observations in the context of the proposal that the object is the result of a major merger and point out some observational discrepancies from this explanation. We argue that an alternative scenario that could better fit the observations may be the slow accretion of cold intergalactic gas, focused by a dense filament of galaxies in which this object is embedded

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Title: HUDF 1619 - a candidate polar-ring galaxy in the Hubble Ultra Deep Field
Authors: V.P. Reshetnikov, R.-J. Dettmar

 A good candidate for a polar-ring galaxy has been detected in the Hubble Ultra Deep Field (HUDF). The galaxy HUDF 1619 (V~25 mag, z~1) is the most distant object of this type known to date. A large-scale structure crosses the highly warped disk of the main galaxy seen almost edge-on at an angle of about 70 grad. The luminosity of this structure (the possible polar ring) reaches ~1/3 of the luminosity of the central galaxy. A strong absorption lane is seen in the region where this structure is projected onto the disk of the central object. There are two galaxies of comparable luminosity adjacent to HUDF 1619 (in projection). One of them may be the donor galaxy in the interaction which gave rise to the ring structure.

arXiv:astro-ph/0703784v1 (PDF)

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