NGC 4565 Galaxy is a spiral galaxy located in the direction of the Coma Berenices constellation and is seen almost exactly edge-on from Earth. It was discovered by William Herschel on April 6, 1785. The galaxy is popularly referred to as the “Needle Galaxy,” a name that, while unofficial, is widely used due to its slender appearance when viewed edge-on.

NGC 4565 is listed under number 4565 in the New General Catalogue (NGC) system. Due to its visual characteristics and structural symmetry, it is frequently referenced in observational astrophysics studies.

^{NGC 4565 Galaxy (NASA)}

Location and Observability

NGC 4565 is located at a distance of approximately 30 to 50 million light-years. These distance measurements are determined through indirect methods such as Cepheid variable stars and the Tully-Fisher relation. Its position in the sky allows it to be easily observed with a telescope by both amateur and professional astronomers. Its coordinates are approximately right ascension (RA) 12h 36m and declination (Dec) +25° 59′.

^{Location of NGC 4565 Galaxy (NASA)}

Morphological Features and Dust Structure

NGC 4565 is morphologically classified as an SA(s)b type spiral galaxy. According to this classification, the galaxy is unbarred (SA), has distinct spiral arms (s), and moderately tightly wound arms (b). Although the galaxy’s edge-on orientation makes it difficult to directly observe its structural details, its dense dust disk and outer disk structure can be clearly examined from this perspective.

NGC 4565 has a prominent central bulge and a dark dust lane. The dust lane extends symmetrically along the galaxy’s center and partially absorbs starlight, affecting observation. This structure is important for understanding the density and composition of the interstellar medium. Infrared observations show that this dust largely contains carbon-based compounds and silicate grains.

Kinematic Properties and Star Formation

Radio and optical observations have played an important role in analyzing the rotation curve of NGC 4565. Its edge-on structure allows for direct measurement of rotation velocity. Measurements indicate that the rotational velocities of stars and gas in the outer regions remain constant, supporting the existence of dark matter in this galaxy as well. Observations made with H I lines reveal that most of the galaxy’s mass consists of invisible components.

NGC 4565’s stellar population comprises various age groups. Older and more metal-rich stars dominate the central region, while the disk contains regions of ongoing star formation. However, the star formation rate appears lower compared to similarly sized face-on spiral galaxies; this is thought to be largely a result of observational bias due to the viewing angle.

Satellite Galaxies and Multiwavelength Observations

Several low-mass satellite galaxies have been detected near NGC 4565. The most prominent of these is a small spiral galaxy named NGC 4562. NGC 4565 is a member of the local galaxy group known as the Coma I Group. However, this group is believed to exhibit relatively weak gravitational interaction, suggesting that NGC 4565 has undergone largely isolated evolution.

NGC 4565 has been observed in different regions of the electromagnetic spectrum using various telescopes. In visible light, its dust lanes and central bulge are especially prominent. Infrared observations provide information about star-forming regions and dust distribution. H I radio observations reveal the extent and dynamic structure of neutral hydrogen. X-ray observations have shown sources in the central region that may indicate low-level active galactic nucleus activity.

Scientific Significance

NGC 4565 serves as a reference in comparative galactic studies due to its structural similarity to the Milky Way. In particular, the analysis of edge-on galaxies enables the study of disk thickness, bulge shapes, and dust distribution. This galaxy is also frequently cited in research concerning dark matter distribution, the geography of star formation, and evolutionary scenarios.

NGC 4565 is a comprehensively studied spiral galaxy in the nearby universe in terms of morphological, kinematic, and star formation properties. As a significant model for the structural analysis of edge-on galaxies, NGC 4565 provides meaningful contributions to our understanding of galactic evolution and dynamics through data supported by multiwavelength observations.