NGC 3628 Galaxy is an unbarred spiral galaxy located in the constellation Leo, observed edge-on from Earth. Although this galaxy is often referred to in astronomical sources as the "Hamburger Galaxy," such nicknames are not used in academic contexts. NGC 3628 is a member of the galaxy group known as the "Leo Triplet", along with Messier 65 (M65) and Messier 66 (M66). This structure provides an important area of study, particularly for observing interactive galaxy dynamics and external gravitational effects.
NGC 3628 Galaxy (NASA)
Discovery and Initial Observation
NGC 3628 was discovered on April 8, 1784, by the German-born British astronomer William Herschel. It was later included in the New General Catalogue (NGC), published in the late 19th century, under the number 3628. Early observations were limited to visual telescopes, but from the 20th century onward, more comprehensive analyses have been conducted using spectroscopic and radio astronomical techniques.
Structural Features
According to the Hubble classification system, NGC 3628 falls between the SBb and Sc morphological types. However, due to the galaxy being observed edge-on, this classification involves certain uncertainties. The galaxy has a diameter of approximately 100,000 light-years and is characterized by a prominent dark dust lane. This dust lane stretches along the disk of the galaxy in optical images and provides insight into the distribution of interstellar matter.
NGC 3628 is rich in hydrogen (H I) and molecular gas (particularly CO). This indicates the presence of active star-forming regions within the galaxy. Observations made in the infrared and radio wavelengths have revealed intense star formation and the existence of supernova remnants in the galaxy’s core. The disturbed structure of the galaxy’s planar velocity field is most likely a result of interactive galaxy dynamics.
Interaction with the Leo Triplet and Multiwavelength Observations
NGC 3628 is in gravitational interaction with the other galaxies in the Leo Triplet, namely Messier 65 and Messier 66. One of the most striking pieces of evidence for this interaction is a tidal tail extending from NGC 3628, approximately 300,000 light-years in length. This tail structure serves as a key example for observing dynamic processes such as intergalactic matter transfer, triggered star formation, and structural disruptions.
NGC 3628 has been observed not only in the optical band, but also in the infrared, ultraviolet, X-ray, and radio wavelengths. Observations by the Chandra X-ray Observatory have revealed intense X-ray emission from the galaxy’s center, which is associated with active star-forming regions and possible supernova remnants. Additionally, data from the Spitzer Space Telescope have been used to map dust densities in the galaxy.
Halo Structure and Scientific Significance
The rotation curves of NGC 3628 show unexpectedly high velocities, especially in the outer regions. This observational data suggests that the galaxy contains a significant dark matter halo. Modeling the distribution of dark matter is essential for analyzing both intragalactic and intergalactic interactions. In this context, NGC 3628 serves as a case study in dark matter research.
NGC 3628 is an important example for many astrophysical research areas, such as galaxy evolution, galactic interactions, and star formation processes. The study of its tidal tail and dense star-forming regions provides insights into how galactic mergers and collisions occur on cosmological timescales. At the same time, the galaxy’s dark matter structure is valuable for modeling the distribution of dark matter in the local universe.
In conclusion, NGC 3628 is an edge-on unbarred spiral galaxy located in the constellation Leo. With its structural features, star-forming regions, gas density, and interactive galaxy dynamics, it serves as a suitable example for astrophysical studies. Due to its interactions within the Leo Triplet and its prominent tidal tail, this galaxy has been the subject of numerous observational and theoretical studies on galaxy evolution and dark matter.
