NGC 1553
| NGC 1553 | |
|---|---|
NGC 1553 core by HST. 0.3′ view
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| Observation data (J2000 epoch) | |
| Constellation | Dorado |
| Right ascension | 04h 16m 10.5s |
| Declination | −55° 46′ 49″ |
| Redshift | 1080 ± 11 km/s |
| Distance | 78.9 Mly(24.2 Mpc) |
| Apparent magnitude (V) | 10.3 |
| Characteristics | |
| Type | SA(rl)00 |
| Apparent size (V) | 4′.5 × 2′.8 |
| Other designations | |
| PGC 14765,IRAS 04150-5554,ESO 157-17, and AM 0415-555 | |
NGC 1553 is a prototypicallenticular galaxy in the constellation Dorado. It is the second brightest member of the Dorado Group of galaxies. British astronomer John Herschel discovered NGC 1553 on December 5, 1834 using an 18.7 inch reflector.
It forms a pair of interacting galaxies together with elliptical NGC 1549 which lies 11′.8 away from it in the sky. Their interaction appears to be in the early stage and can be seen in optical wavelengths by faint but distinct irregular shells of emission and a curious jet on the northwest side. Together, these two galaxies comprise the center of the Dorado group.
NGC 1553 is an early type galaxy with a luminosity of 4×1010L⊙. It has been detected in H I but has an H I mass to B-band luminosity ratio (MHI/LB) of less than 0.01. NGC 1553's ultraviolet spectrum shows weak flux under the main-sequence turn off at around 2,400 A°. This is characteristic of old intermediate populations of quiescent lenticular galaxies.
NGC 1553 has an especially well developed lens (~36″) component of nearly constant surface brightness that is found between the bulge and the exponential disk. Its lens is similar to what is found in NGC 3945 and its inner parts are very hot.
NGC 1553 has associated with itself cool gas and dust. It can also be seen in infrared and is a weak radio source.Hubble observations in 2000 revealed an inner torus-like dust lane about 3″ across at the galaxy's center.
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