NGC 4561 is a barred spiral galaxy in the constellation Coma Berenices. It was discovered by German-British astronomer William Herschel on April 13, 1784.[8] This galaxy is located at a distance of 82 ± 14 million light-years (25.2 ± 4.3 Mpc) from the Milky Way,[4] and is a member of the Virgo Cluster of galaxies.[5] It is 13th magnitude with an angular size of 1.5′.[9]
NGC 4561 | |
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Observation data (J2000 epoch) | |
Constellation | Coma Berenices |
Right ascension | 12h 36m 08.137s[1] |
Declination | +19° 19′ 21.32″[1] |
Redshift | 0.00454±0.00020[2] |
Heliocentric radial velocity | 1,410 km/s[3] |
Distance | 82 ± 14 Mly (25.2 ± 4.3 Mpc)[4] |
Group or cluster | Virgo Cluster[5] |
Apparent magnitude (B) | 12.70[3] |
Characteristics | |
Type | SB(rs)dm,[6] Sc(dSc)[3] |
Number of stars | 1.23×109 M☉[5] |
Apparent size (V) | 0.727′ × 0.581′[1] (NIR) |
Other designations | |
2MASX J12360813+1919213, NGC 4561, UGC 7768, PGC 42020[7] |
The morphological classification of NGC 4561 in the De Vaucouleurs system is SB(rs)dm,[6] indicating a barred spiral galaxy (SB) with a transitional inner ring structure (rs), loosely wound spiral arms (d), and an irregular appearance with no bulge component (m). The galactic plane is inclined at an angle of 28° to the plane of the sky, with the major axis aligned along a position angle of 60°.[5] It has a star formation rate of 0.23 M☉·yr−1. The net stellar mass of the galaxy is 1.23×109 M☉.[5]
A nuclear X-ray source was detected in NGC 4561 by Chandra, and was determined to be an active galactic nucleus based on XMM-Newton observations. It has a small supermassive black hole at the source, with a mass of at least 2×104 M☉.[10]