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Arp Bot 🤖 @arpbot.bsky.social · 3h

Image of Arp 18, also known as NGC 4088, from Halton Arp's Atlas of Peculiar Galaxies (1966).

In the original catalog it was in the category: Spiral galaxies - Detached segments. NGC 4088 is located about 40 million light years away.
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A grainy, black and white image of a galaxy, which is slightly inclined, so it forms an oval shape, rather than a circle. The galaxy's stars and gas form a loose two-armed barred spiral, forming an S-shape. Dark, filamentary dust lanes are seen throughout the spiral arms. At the top edge of the galaxy, in line with the bar, is what looks like a third spiral arm. A few dots, which are stars, are seen on the black background.

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Arp Bot 🤖 @arpbot.bsky.social · 15h

Chandra and Hubble image of Arp 302, also known as UGC 9618 or VV 340.

The Chandra data (pink) shows that the upper galaxy has an obscured, active supermassive black hole.

Credit: NASA, CXC, IfA, D.Sanders et al, STScI, NRAO, A.Evans et al
Source

$A pair of spiral galaxies. The lower galaxy is seen face-on. It has a bright center and short bar structure that transitions into a series of loosely-wound spiral arms, looking something like a cinnamon roll. The arms are dotted with blue star clusters and crossed by darker dust filaments. A diffuse pink glow covers the center of the galaxy. The upper galaxy is seen edge on. It has a somewhat puffy disk, seen as a wide, vertical line. Running down the middle is a dark dust lane. A bright pink glow fills the center of the galaxy, extending beyond the disk. In the middle of the frame, where the two galaxies appear to touch, is a bright foreground star with four diffraction spikes. Other distant galaxies and stars fill the black background of space.$

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Arp Bot 🤖 @arpbot.bsky.social · 1d

Image of Arp 283, also known as NGC 2798 and NGC 2799, from Halton Arp's Atlas of Peculiar Galaxies (1966).

In the original catalog it was in the category: Double and multiple galaxies - Infall and attraction. A bridge connect the pair.
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A grainy, black and white image of a pair of interacting galaxies. The galaxy on the right is seen edge-on. It has a bright central core and a slightly warped disk that is dotted with star clusters and clumps of dark dust. The edge of the disk arcs to the right, appearing to connect to its companion galaxy. The second galaxy is inclined, but seen closer to face-on. Two spiral arms emerge from the core, which are wide and poorly defined.

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Arp Bot 🤖 @arpbot.bsky.social · 1d

Also known as Arp 189.

Daniel Pomarède @pomarede.bsky.social · 2d

CFHT Astronomy Image Of The Month

The Umbrella Galaxy (NGC 4651)

Credits: data obtained using the MegaCam camera on the Canada-France-Hawaii Telescope; image by Jean-Charles Cuillandre (CFHT) & Giovanni Anselmi (Coelum); copyright © 2025 CFHT
www.cfht.hawaii.edu/HawaiianStar... 🧪🔭

A photography of the spiral galaxy NGC 4651. This member of the Virgo Cluster is known as the Umbrella Galaxy due to the umbrella-shaped structure that extends from its disk and that is composed of stellar streams, being the remnants of a much smaller galaxy that has been torn apart by NGC 4651's tidal forces.

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Arp Bot 🤖 @arpbot.bsky.social · 1d

Kitt Peak image of Arp 94, also known as NGC 3226 and NGC 3227.

The large spiral galaxy, NGC 3227 is interacting with its elliptical galaxy companion, NGC 3226. Faint tidal streams of gas and dust link the pair.

Credit: KPNO,NOIRLab,NSF/AURA/Sid Leach and Wil Milan/Adam Block
Source

Two interacting galaxies. A large spiral galaxy with reddish brown dust lanes is in the center left of the image. It is tilted slightly, so that its disk forms an oval rather than a circle. The very faint ends of spiral arms extend beyond the edge of the disk and appear to connect to its companion galaxy. In the center right is a bright elliptical galaxy. It is oval shaped with a bright center that gets gradually fainter and more transparent towards its edges. The black background of space is dotted with foreground stars and tiny background galaxies.

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Arp Bot 🤖 @arpbot.bsky.social · 2d

Image of Arp 293, also known as NGC 6285 and NGC 6286, from Halton Arp's Atlas of Peculiar Galaxies (1966).

In the original catalog it was in the category: Double and multiple galaxies - Wind effects. The pair's interactions pull tidal streams.
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A grainy, black and white image of a pair of interacting spiral galaxies. The galaxy on the right is seen nearly face-on. It has a bright disk. At the edges of the disk are two short, faint, wide spiral arms. The galaxy on the left is seen edge-on. It's disk forms a line. In the center of the galaxy, the circular bulge emerges on either side of the disk. The black background of space is dotted with stars and small background galaxies. The black background of space is filled with white dots, which are foreground stars.

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Arp Bot 🤖 @arpbot.bsky.social · 3d

Image of Arp 16, also known as M66, from Halton Arp's Atlas of Peculiar Galaxies (1966).

In the original catalog it was in the category: Spiral galaxies - Detached segments. M66 has loose arms full of young star clusters.
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A grainy, black and white image of a nearly face-on barred spiral galaxy. It has a bright core. Two spiral arms start at the center and extend outward, rotating clockwise. They are crossed by dark dust lanes. Several white dots, which are stars, are seen on the black background.

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Arp Bot 🤖 @arpbot.bsky.social · 3d

Hubble image of Arp 290, also known as IC 195 and IC 196.

This interacting galaxy pair consists of a larger barred spiral (IC 196, top) and a smaller intermediate spiral (IC 195, bottom).

Credit: NASA, ESA, STScI, Julianne Dalcanton, Meli thev, Wikimedia Commons
Source

A greyscale image of two interacting spiral galaxies. The larger galaxy in the upper part of the frame has a bright central core surrounded by a long bar structure. The bar is crossed by dark dust lanes. Emerging from the bar is the beginning of one spiral arm at about 6 o'clock that curves upward. There are additional, barely visible spiral arms that wrap around the galaxy. The smaller galaxy in the bottom left portion of the frame also has a bright core, surrounded by an oval-shaped central region, and very faint, wispy spiral arms. The black background of space is filled with foreground stars and tiny background galaxies. The image has a noticeable amount of detector noise which has not been removed.

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Arp Bot 🤖 @arpbot.bsky.social · 4d

GALEX and SDSS image of Arp 24, also known as NGC 3445.

The left image from GALEX shows NGC 3445 in ultraviolet light. The right image shows the same galaxies from the Sloan Digital Sky Survey in visible light.

Credit: Fig. 1 from Smith et al. 2010.
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A two-panel image. The left panel is labeled Arp 24 GALEX. A scale bar marks 1 arcminute, which is about 1/8 the width of the frame. The panel shows a low-res image in shades of yellow and blue. The frame is dominated by the large spiral. It has a small core that sits in the middle of a spiral structure. The one spiral arm begins at about 9 o'clock and curves clockwise around the galaxy, completing a full circle. The arm is unusually thick, fanning out with many bright, whiteish-blue star clusters. To the left of the spiral is a smaller galaxy, seen almost edge-on. It appears as an elongated oval dotted with stars. The long axis of the oval is almost horizontal. Connecting the two galaxies is a faint bridge of stars. A large yellow dot, which is a bright foreground star, fills the upper left corner.
The right panel is labeled Arp 24 SDSS and has a similar 1 arcminute scale bar. It shows the same galaxies at the same scale and is higher resolution. The star clusters in the spiral are better resolved, appearing as small blue dots.

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Arp Bot 🤖 @arpbot.bsky.social · 4d

JWST NIRCam image of Arp 107, also known as UGC 5984.

In this near-infrared view, older stars appear white. The tenuous bridge of gas and stars as well as the diaphanous area to the bottom left are signs of past interactions.

Credit: NASA, ESA, CSA, STScI
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A pair of interacting galaxies. The larger of the two is slightly right of center. It is a one-armed spiral galaxy with a hazy, bright, white center and a ring of stars and gas, which are shades of blue-grey. Mixed within them are filaments of glowing red dust. The single spiral arm begins at about the 7 o'clock position and spirals counterclockwise to the 12 o'clock position, forming a ring structure. Toward the bottom left and right of the ring are filaments of gas spiraling inward toward the core. At the top left of the ring, at the 11 o'clock position, is a noticeable gap, bordered by two large, orange pockets of dust and gas. The smaller elliptical galaxy to its left is made of hazy white gas and dust, which becomes more diffuse farther away from its center. To this galaxy’s bottom left, there is a smaller, more diffuse haze of stars and gas that wafts outward toward the edges. An diaphanous arched stream connects the two galaxies. Many red, orange, and white galaxies are spread throughout the background, with some hazier in composition and others having defined spiral patterns.

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Arp Bot 🤖 @arpbot.bsky.social · 5d

Image of Arp 84, also known as NGC 5394 and NGC 5395, from Halton Arp's Atlas of Peculiar Galaxies (1966).

In the original catalog it was in the category: Spiral galaxies - Large, high surface brightness companions.
Source

$A grainy, black and white image of a pair of interacting spiral galaxies that somewhat resembles a heron. To the upper right is a smaller, distorted spiral, forming the heron's neck, head, and beak. In its center is a bright nucleus surrounded by a ring of stars. Extending from the ring are two large, thin spiral arms, dotted with star clusters, which form an S-shape. The lower arm appears to touch the edge of the disk of its companion galaxy. On the left is a large spiral galaxy, forming the heron's body. It's disk is tilted, so that it appears as a oval rather than a circle. It has a bright center that transitions into spiral arms. The arms are defined by dark brown dust lanes. The area in between is filled with a haze of bright stars. On the black background of space are foreground stars, some with diffraction spikes, and tiny background galaxies. A few white dots, which are stars, are seen on the black background of space.$

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Arp Bot 🤖 @arpbot.bsky.social · 5d

image of Arp 193, also known as IC 883.

IC 883 is likely the remnant of the merger of two disk galaxies, since it has two tidal tails. The merger triggered a burst of star formation, creating the bright star clusters seen in the center.

Credit: NASA, ESA, STScI
Source

In the center of the frame is a roughly oval-shaped galaxy merger remnant, made out of a swirling blue-white haze of stars and gas. Crossing the center of the remnant is a dark brown filament of dust. Emerging from the remnant are two tidal tails, long thin lines of gas and stars. They are approximately the same length emerging at nearly right angles: one diagonally to the top right of the frame and the other to the bottom right. . Scattered across the background there are foreground stars and background galaxies of various sizes.

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Arp Bot 🤖 @arpbot.bsky.social · 6d

JWST NIRCam and MIRI image of Arp 142, also known as NGC 2936, NGC 2937, and UGC 5130, or the Penguin and the Egg.

The Penguin is a spiral galaxy whose shape has been distorted by the gravity of the elliptical Egg galaxy.

Credit: NASA, ESA, CSA, STScI
Source

$Arp 142, two interacting galaxies, observed in near- and mid-infrared light. At left is NGC 2937, nicknamed the Egg. Its center is brighter and whiter. There are six diffraction spikes atop its gauzy blue layers. At right is NGC 2936, nicknamed the Penguin. Its beak-like region points toward and above the Egg. Where the eye would be is a small, opaque yellow spiral. The Penguin’s distorted arms and orange dust lanes from the bird’s beak, back, and tail. The tail is wide and layered, like a beta fish’s tail. A semi-transparent blue hue traces the Penguin and extends from the galaxy, creating an upside-down U over top of both galaxies. At top right is another galaxy seen from the side, pointing roughly at a 45-degree angle. It is largely light blue. Its length appears approximately as long as the Egg’s height. One foreground star with large, bright blue diffraction spikes appears over top of the galaxy and another near it. The entire black background is filled with tiny, extremely distant galaxies.$

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Arp Bot 🤖 @arpbot.bsky.social · 6d

Image of Arp 85, also known as the Whirlpool Galaxy or M51, from Halton Arp's Atlas of Peculiar Galaxies (1966).

In the original catalog it was in the category: Spiral galaxies - Large, high surface brightness companions.
Source

A grainy, black and white image of two galaxies. The larger of the two galaxies, a spiral, is on the left side of the image. Two well-defined arms extend to from its center and form loose spirals around the middle. The smaller galaxy on the far-right side is fuzzy sphere. The view of this smaller galaxy is partially obstructed by the tip of one of the arms of the spiral galaxy, which appears to cover the top third of the smaller galaxy. Many white dots, stars, are seen on the black background.

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Arp Bot 🤖 @arpbot.bsky.social · 7d

Gemini South image of Arp 271, also known as NGC 5426 and NGC 5427.

This pair of galaxies are tugging on each other with gravity. We can see this interaction in the bridge of stars connecting the galaxies.

Credit: International Gemini Observatory, NOIRLab, NSF, AURA
Source

Two similar-looking spiral galaxies take up most of the frame. They both have bright, yellow-white central cores and well-defined spiral arms dotted with pink star forming regions. NGC 5427 is a nearly face-on spiral galaxy at lower left. NGC 5426 is a more oblique galaxy at upper right. The two spiral arms on the upper side of NGC 5426 appear as a bridge that connects with NGC 5427. The black background of space is dotted with stars and small background galaxies.

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Arp Bot 🤖 @arpbot.bsky.social · 7d

Hubble image of Arp 297, also known as NGC 5754 and NGC 5752.

The pair's interactions created kinked arms in NGC 5754 (the large spiral galaxy) and the blue star clusters in the core of NGC 5752 (the smaller galaxy).

Credit: NASA, ESA, the Hubble Heritage team, W. Keel
Source

A pair of galaxies, a large face-on barred spiral galaxy and a smaller edge-on disk galaxy. The upper portion of the frame is dominated by the spiral galaxy NGC 5754. It has a bright, pale yellow, circular core that transitions into an almost vertical bar structure. Two well-defined spiral arms circle around the core counter-clockwise, beginning at the ends of the bar. The arms both complete one revolution around the core and then fade out. They are dotted with pale blue star clusters. At about 5 and 7 o'clock on the bottom of the galaxy, the spiral arms have small kinks, creating what looks like straight segments in the otherwise smoothly curving arms. Overall, the galaxy looks a little like a cinnamon roll. In the bottom left corner of the frame is the smaller companion galaxy NGC 5752. It is oval-shaped, with the long axis almost vertical, running parallel to the bar of the large spiral. On a background of pale yellow stars is a line of blue dots, which are star clusters, running through the long axis in the center of the galaxy. Below this is a dark brown dust lane.

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Arp Bot 🤖 @arpbot.bsky.social · 8d

JWST MIRI image of Arp 142, also known as NGC 2936 and NGC 2937, or the Penguin and the Egg.

The Egg appears as a small teal oval made of the oldest stars in the elliptical galaxy. The Penguin's distorted spiral is made of cool gas and dust.

Credit: NASA, ESA, CSA, STScI
Source

$Two interacting galaxies known as Arp 142 in a horizontal image taken in mid-infrared light. At left is NGC 2937, an elliptical galaxy that looks like a tiny teal oval and is nicknamed the Egg. At right is NGC 2936, a distorted spiral galaxy nicknamed the Penguin, which is significantly larger. A beak-like region points toward the Egg, but lies far above it. Where the eye would be is an opaque, almost washed-out pink spiral. This galaxy’s distorted pink, purple, and blue arms create the bird’s beak, back, and tail. The tail, which is closer to the Egg, is wide and layered, like a beta fish’s tail. The Penguin and the Egg appear very separate. The galaxy at top right, PGC 1237172, is barely visible. A brighter slightly larger blue foreground star that is over top of this galaxy has tiny diffraction spikes. Throughout the image are tiny galaxies in bright reds, greens, and blues. The background of space is black.$

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Arp Bot 🤖 @arpbot.bsky.social · 8d

Spitzer image of Arp 82, also known as NGC 2535 and NGC 2536.

The larger galaxy's inner arms have evenly spaced "beads on a string" star clusters, likely created by recent gravitational interactions that led to a burst of star formation.

Credit: NASA, JPL-Caltech, M. Hancock
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$A somewhat low-res image of a pair of interacting spiral galaxies. In the center of the frame is the larger galaxy, a spiral galaxy seen face-on. It has a bright yellow center. A ring of pink and blue stars and star clusters circles the center, giving the inner part of the galaxy a shape that resembles an eye. Two long spiral arms emerge from the ring, dotted with blue star clusters, forming an S-shape. The upper arm trails off in a faint arc to the right. The bottom arm appears to connect to its companion galaxy in the lower part of the frame. This galaxy is smaller and blobby, but resembles a two-armed spiral with a bright center and wider, hazy arms. The black background of space is dotted with green dots, which are foreground stars. A few particularly bright stars with four diffraction spikes are seen to the right of the center galaxy.$

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Arp Bot 🤖 @arpbot.bsky.social · 9d

Sloan Digital Sky Survey image of Arp 285, also known as NGC 2854 and NGC 2856.

This pair of galaxies is connected by a bridge of material, indicating a past interaction. The upper galaxy, NGC 2856, also has a clumpy tail perpendicular to its disk.

Credit: SDSS
Source

$A somewhat low-res image of a pair of widely-space interacting spiral galaxies. The galaxy in the top left has a bright disk seen at a slight angle so that it appears oval-shaped. Its spiral arms are fainter and hard to see. A thin, blue, clumpy line extends above the galaxy, perpendicular to its disk. The galaxy in the lower right has a strong bar and two spiral arms, forming a distinct S shape. The bar is brighter and yellow-ish. The arms are bluer and dotted with teal star clusters. Faint streams of blue material extend outwards from the ends of the spiral arms. The top stream almost connects with the galaxy in the top left. Several foreground stars are seen as bright points with eight diffraction spikes. The black background of space is dotted with stars and small background galaxies$

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Arp Bot 🤖 @arpbot.bsky.social · 9d

JWST and Hubble image of Arp 142, also known as NGC 2936 and NGC 2937, or the Penguin and the Egg.

In Hubble’s visible light image (left) a dark brown dust lane crosses the Penguin. In Webb’s near-infrared view (right), this dust is fainter.

Credit: NASA, ESA, CSA, STScI
Source

Frame is split down the middle: Hubble’s visible light image at left, and Webb’s near-infrared image at right. Both show the Egg at left and the Penguin at right. In Hubble’s view, the Penguin is highly detailed, with a bright blue beak, body, and tail that is covered in an arc of bright brown dust. The Egg, to its left, appears bright, gleaming yellowish white. At top right is another galaxy seen from the side, about as long as the Egg’s height. Dozens of galaxies and stars appear in the background. Webb’s near-infrared image shows the Penguin’s beak, head, and back in shades of pink. It’s tail-like region is more diffuse, and a mix of lighter pinks and blues. The Egg appears slightly larger in blue layers. A semi-transparent blue forms an upside down U over top of both galaxies. At top right, an edge-on galaxy has many more pinpricks of light, which are stars. Thousands of galaxies and stars appear in the background. Some galaxies are shades of orange, while others are white.

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Arp Bot 🤖 @arpbot.bsky.social · 10d

Gran Telescopio Canarias image of Arp 188, also known as the Tadpole Galaxy.

It is a result of a recent galactic interaction. A small intruder galaxy created a 280,000 light-year-long tail, dotted with clusters of massive, young stars.

Credit: GTC, IAC, D. López
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In the center right part of the frame is a spiral galaxy with a bright orange-white central core encircled by two blue, wispy arms that form a loose spiral around the core. The view is somewhat oblique, giving the galaxy an oval appearance. A long, thin, diffuse stream of stars and gas extends from the left side of the galaxy to the center of the image. The spiral arms and the tail are dotted with blue star clusters. Scattered across the background there are foreground stars and tiny background galaxies.

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Arp Bot 🤖 @arpbot.bsky.social · 10d

Hubble image of Arp 299, also known as NGC 3690.

This image was taken in 2000 with Hubble WFPC2 instrument to study the merging galaxies' hottest and brightest stars in ultraviolet light.

Credit: NASA, R. Windhorst, and the Hubble mid-UV team
Source

Two merging galaxies form an orange and blue abstract butterfly shape. Within the shape are bright blue areas, which are clusters of young, hot stars. These are found in the center, the upper right "wing", and the bottom left "wing".

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Arp Bot 🤖 @arpbot.bsky.social · 11d

Image of Arp 297, also known as NGC 5755, NGC 5753, NGC 5754 and NGC 5752, from Halton Arp's Atlas of Peculiar Galaxies (1966).

In the original catalog it was in the category: Double and multiple galaxies - Long filaments.
Source

A grainy, black and white image of four small galaxies, arranged in two pairs. The right pair of galaxies is a large face-on barred spiral galaxy and a smaller edge-on disk galaxy. The spiral has a bright, circular core that transitions into a diagonal bar structure. Two well-defined spiral arms circle around the core counter-clockwise, beginning at the ends of the bar. Above it is its smaller companion galaxy. It is oval-shaped, running diagonal and with the long axis parallel to the bar of the large spiral. The left pair is two nearly face-on spiral galaxies. The bottom galaxy of the pair has a bright core and asymmetric bar with two faint spiral arms that make an S-shape. The top galaxy of the pair has a bright core and just a hint of spiral arms. Many white dots, which are stars, are seen on the black background.

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Arp Bot 🤖 @arpbot.bsky.social · 11d

Image of Arp 116, also known as M60 and NGC 4647, from Halton Arp's Atlas of Peculiar Galaxies (1966).

In the original catalog it was in the category: Elliptical galaxies - Close to and perturbing spiral galaxies. The pair is beginning to interact.
Source

A grainy, black and white image of a large elliptical galaxy and a smaller face-on spiral galaxy. The elliptical galaxy is in the lower right portion of the frame. It appears as a featureless, oval-shaped blob surrounded by a haze of stars. Above and to its left is its companion, a smaller face-on spiral galaxy. Its somewhat poorly defined spiral arms curve around its bright center. The arms are dotted with bright stars and star clusters and are crossed by a series of filamentary dust lanes. Many white dots, which are stars, are seen on the black background.

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Arp Bot 🤖 @arpbot.bsky.social · 12d

Hubble image of Arp 22, also known as NGC 4028.

NGC 4027 is a barred spiral galaxy with a single spiral arm. It is interacting with a smaller companion galaxy, NGC 4027A, just out of frame.

Credit: NASA, ESA, STScI, Julianne Dalcanton, Meli thev, Wikimedia Commons
Source

A greyscale image of face-on spiral galaxy. In the center is a small bar structure. A single large blue spiral arm begins at the top and curves counter-clockwise from about the 11 o'clock to 9 o'clock positions. This gives the galaxy a teardrop-shape with a curved end, so that it resembles a paisley. Dark dust lanes, star clusters are scattered throughout the galaxy.

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