| NGC 5448 | |
|---|---|
 NGC 5448 imaged by the 32-inch Schulman Telescope atMount Lemmon Observatory | |
| Observation data (J2000epoch) | |
| Constellation | Ursa Major |
| Right ascension | 14h 02m 50.0608s[1] |
| Declination | +49° 10′ 21.402″[1] |
| Redshift | 0.006725 ± 0.000005[1] |
| Heliocentric radial velocity | 2,016 ± 1 km/s[1] |
| Distance | 95.6 ± 28.2Mly (29.3 ± 8.6Mpc)[1] |
| Group orcluster | NGC 5448 Group |
| Apparent magnitude (V) | 11.2[2] |
| Characteristics | |
| Type | (R)SAB(r)a[1] |
| Size | ~120,000 ly (36.7 kpc) (estimated)[1] |
| Apparent size (V) | 3.8′ × 2.0′[2] |
| Notable features | LINER |
| Other designations | |
| IRAS 14009+4924,UGC 8969,MCG +08-26-003,PGC 50031,CGCG 247-004[1] | |
NGC 5448 is aspiral galaxy in the constellationUrsa Major. The galaxy lies about 95 millionlight years away from Earth based on redshift-independent methods, which means, given its apparent dimensions, that NGC 5448 is approximately 120,000 light years across.[1] It was discovered byWilliam Herschel on May 15, 1787.[3]
The galaxy has an ellipticalbulge with boxy outerisophotes and an X-shape. A low-surface-brightnessbar is seen running diagonally in the bulge.[4] Stellar kinematics indicate that there is a small stellar disk in the inner 7 arcseconds of the galaxy, which is inclined by about 13 degrees with the respect to the rest of the galaxy.[5] The stellar population in the centre of the galaxy is younger than that of the rest of the surrounding area.[6] In images byHubble Space Telescope a prominent dust lane is visible in the circumnuclear region of the galaxy and three more diffuse a bit further away.[5]
Spiral arms emerge from the ends of the bar and wrap around forming a nearly completering. The arms are initially broad and high-contrast but after 45° degrees of revolution become narrow, while after completing a quarter of a revolution they start to branch. The galaxy has faint outer arms.[4] ManyHII regions are visible in the inner arms, while knots are also visible in the outer arms.[7] Many dust lanes are visible across the disk.[5]
The nucleus of the galaxy has been found to beactive and based on its emission lines has been identified as a type 2LINER.[8] The most accepted theory for the energy source of active galactic nuclei is the presence of anaccretion disk around asupermassive black hole. The mass of the black hole in the centre of NGC 5448 is estimated to be 107.3 (20 million)M☉ based on the absolute bulge magnitude.[9]
The galaxy is seen at high inclination viewed at an angle of 64°.[5]
NGC 5448 is the foremost member of the NGC 5448 Group, also known as LGG 372. Other members of the group includeNGC 5425,NGC 5480,NGC 5481,NGC 5520,NGC 5377, andNGC 5500.[10][11]
