Arp 91 / NGC 5953/5954

Designation(s)Arp 91, NGC 5953, NGC 5954
Object Type(s)Galaxy
Relevant Catalog(s)All (Chron), Arp, NGC
Arp CategorySpiral galaxies with large high surface brightness companions on arms
Obs. Lat/Long42° 17', 073° 57'
ConstellationSerpens
Date and Time Observed2024-05-23 22:27:00
InstrumentEdgeHD 8" f10-2,032mm FL
CameraASI294MC-Pro
Image DetailsUp is 1.0 degrees E of N. Total integration time was 33m 30s. Exposures 30s@305g, UV/IR Cut Filter. Darks subtracted, no flats. Dithered and recentered in SharpCap. No guiding.
DescriptionNGC 5954 and 5953 are pretty small, but bright enough to capture even during a nearly full moon (luckily pointing to a very different part of the sky). They appear to be merging (or at least strongly interacting during a "fly by"). NGC 5954 (left) is an elongated spiral, though it's unclear to me whether the elongation was caused by this interaction or an earlier one. I suspect the latter since the distortion isn't obviously in the direction of its current partner. NGC 5953 (right) is a nearly featureless elliptical galaxy. Arp's remarks, "Broad pec. arm to comp., then absorption: faint extension from comp," accurately describes the connection and suggests they saw one companion. I debated whether there might be two, dwarf galaxies interacting with the primary pair. Both bright objects (SW, lower right, NW, upper right), I continue to interpret as field stars distorted by poor seeing rather than galaxies.
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