Abstract
Arp 93 consists of two interacting galaxies, NGC 7284 and NGC 7284 and a long tidal tail. However, it has not been depicted in its fullest extent in previous images. I present a deep, new image that illustrates the tail's wide path, that is more than double the previously recorded angular distance from the interacting pair of galaxies.
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Arp 93 consists of the merger of the two galaxies NGC 7284 (an elliptical) and NGC 7285 (a spiral). Most images of Arp catalog objects, including survey images, concentrate on showing the detail of the merging galaxies in a relatively tight field of view using long focal lengths. Previous images of Arp 93, either professional or amateur, do not show the extraordinary size and length of its southern tidal tail.
I obtained a series of images totaling 9 hr of exposure time using a 0.32 m PlaneWave corrected Dall Kirkham telescope with a focal length of 2550 mm and an SBIG ST11000 CCD camera. The telescope is located at the "Space Observatory" in Chile's Atacama desert. The image scale is 0
73 per pixel, and the uncropped field of view is 0
81 by 054. Fortyseven 8 minutes exposures were obtained in the "luminance" filter (L). Exposures in red, green, and blue (RGB) filters were 8 × 8 minutes each. The L filter images were obtained without binning, while the CCD was binned 2 × 2 for the RGB data. The images were taken over the nights of 2022 October 2–3.
This very long exposure, wide field image (Figure 1) is the first to show Arp 93's full size, displaying the extent of the extremely large loop of its tidal tail. Deep images of Arp 93, for example, by the Carnegie-Irvine Galaxy Survey (Ho et al. 2011), show a tidal tail extending approximately 3
9 southeast from the core of NGC 7285. This new, wide-field image reveals that the tail curves around to extend out 111 from NGC 7285. There is also tidal debris seen surrounding the two interacting galaxies
Figure 1. A wide-field image of Arp 93 shown with a histogram stretch. The interacting pair, NGC 7284 and NGC 7285, are at the center of the image and shown at a normal stretch in the inset at the lower-right. North is toward the upper-right at this orientation. A faint tidal tail is seen extending out more than 11' from the interacting pair.
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I thank Peter Garnavich, Arielle Phillips, and Debra Elmegreen for helpful discussions.