NGC/IC Project Restoration Effort

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NGC4618

 

Basic Information


Location and Magnitude


Right Ascension: 12:41:33.0
Declination: +41:9:4
Constellation: CVN
Visual Magnitude: 10.8

Historic Information


Discoverer: Herschel W.
Year of discovery: 1787
Discovery aperture: 18.7

Observational


Summary description: B, L, E, mbM, curved branch n
Sub-type: SBm

Corwin's Notes

===== NGC 4618 = IC 3667, which see. I've included the southeastern arm because Vorontsov-Velyaminov has it as one of the components of his "interacting galaxy pair" VV 073. It is not a separate galaxy, of course, but on the POSS1 prints, could perhaps be mistaken for one.

Steve's Notes

===== NGC 4618 48" (4/7/13): fascinating one-armed asymmetric spiral (Arp 23). At 488x the core region is offset to the north side and appeared extremely bright, irregular, elongated 5:3 SW-NE, 1.6'x1.0'. A prominent, thick, knotty arm is attached on the northeast end and sweeps counterclockwise to the south and then west. IC 3669 is a brighter arc or section of the arm, about 1' southeast of the core. IC 3668 appears as a bright, elongated HII region(s) at the south end of the arm (1.7' south of center), ~20"x10". The arm continues to rotate towards the north on the west side of the galaxy, but this feature has a very low surface brightness and ends roughly west of the core. Only a faint, diffuse glow was seen to north of the core on the opposite side of the core, with no structure. The total size of the galaxy extended 3.5'x2.5'. Forms a pair with NGC 4625 8.3' NNE. Interestingly, both galaxies have single prominent arms, though the arm in NGC 4625 was more subtle visually. Member of the CVn II Group (brightest member M106). 18" (5/15/10): This is a very unusual, asymmetric Arp galaxy with a single massive arm (similar to NGC 4027). At 220x it appeared bright, fairly large, obviously irregular, with a slightly elongated main body ~2'x1.5', extended 4:3 SW-NE. Within the main portion of the galaxy a brighter, elongated bar was visible, roughly 1.5'x0.5'. The central bar, though, is displaced to the NW side of entire glow as extending mostly to the south side is a faint, beefy arm that often appears detached and barely connected on the east end of the central region. This broad arm winds counterclockwise from east to south roughly 100¡ with IC 3668, the brightest region or knot near the south end of the arm, ~1.8' from the center of the bar. This single arm increases the overall size to ~3'x2'. IC 3369 refers to the brighter SE portion of the spiral arm. 13.1" (4/12/86): moderately bright, fairly large, faint elongated halo with large brighter core which appears displaced towards the north. This is an unusual one-armed spiral galaxy with a more extensive halo on the south side. Forms a pair with NGC 4625 8.3' NNE. IC 3668 is a knot in the southern arm.