| Eridanus Cluster | |
|---|---|
| Observation data (Epoch J2000) | |
| Constellation(s) | Eridanus |
| Right ascension | 03 28 13.8 |
| Declination | −20° 44′ 40″ |
| Brightest member | NGC 1232 (B) |
| Number of galaxies | ~200 |
| Velocity dispersion | 261 km/s |
| Redshift | 0.005570 |
| Distance | 23 Mpc (75 Mly) |
| ICM temperature | ~10 K (~1 keV) |
| Binding mass | ~10 M☉ |
| X-ray flux | 0.105 mCrab |
| Other designations | |
| Fornax II Cluster, de Vaucouleurs Group 31 | |
The Eridanus Cluster is a galaxy cluster roughly 23 Mpc (75 Mly) from Earth, containing about 73 main galaxies and about 200 total galaxies. About 30% have Hubble classifications of elliptical or S0 and the remaining 70% are spiral or irregular. These galaxies reside in smaller groups which are all loosely gravitationally bound to each other, suggesting that the system is still condensing from the Hubble flow and may eventually form a cluster of about 10 M☉. A low velocity dispersion compared to that of, for example, the Coma cluster, supports this hypothesis. The Eridanus Cluster is located in the constellation Eridanus near the Fornax Cluster, and is sometimes called the "Fornax II Cluster".
Table of galaxies
| Name of the galaxy |
Right ascension for epoch J2000 |
Declination for epoch J2000 |
Blue apparent magnitude of the galaxy |
Galaxy type: E=Elliptical; S0=Lenticular; Sa, Sb, Sc, Sd=Spiral (degree of woundedness of spiral arms); SBa, SBb, SBc, SBd=Barred Spiral; SAB= Intermediate Spiral (between barred and unbarred); Sm, SBm, Irr=Irregular; (r),(rs)=Ring Structure |
Angular diameter of the galaxy (arcminutes) |
Diameter of the galaxy (thousands of light years) |
Recessional velocity (km/s) of the galaxy relative to the cosmic microwave background |
|---|---|---|---|---|---|---|---|
| Name | RA equatorial coordinates |
Dec equatorial coordinates |
Blue Mag |
Type | Size (arcmin) |
Size (kly) |
RV (km/s) |
| ESO 547-09 | 03 06.0 | –19 23 | 16.8 | Irr | 1.3 | 35 | 1509 |
| ESO 547-12 | 03 09.6 | –17 50 | 16.5 | Scd | 1.5 | 35 | 1837 |
| NGC 1232 | 03 09.8 | –20 35 | 10.7 | SAB(rs)c | 6.9 | 170 | 1517 |
| IC 1898 | 03 10.3 | –22 24 | 13.7 | SBc | 3.4 | 85 | 1164 |
| ESO 547-20 | 03 13.0 | –17 56 | 16.0 | SBm | 1.2 | 30 | 1825 |
| NGC 1258 | 03 14.1 | –21 46 | 13.9 | SBc | 1.3 | 30 | 1340 |
| NGC 1297 | 03 19.2 | –19 06 | 13.5 | E | 2.0 | 50 | 1395 |
| NGC 1300 | 03 19.7 | –19 25 | 11.2 | SBbc | 6.0 | 110 | 1421 |
| NGC 1315 | 03 23.1 | –21 23 | 14.0 | S0 | 1.5 | 35 | 1534 |
| PGC 12680 | 03 23.4 | –19 17 | ? | Irr | 1.3 | 30 | 1400 |
| ESO 548-05 | 03 23.8 | –19 45 | 14.7 | SBm | 1.5 | 35 | 1690 |
| NGC 1325 | 03 24.4 | –21 33 | 12.3 | SBbc | 4.7 | 115 | 1446 |
| NGC 1325A | 03 24.8 | –21 20 | 13.6 | SBcd | 1.8 | 45 | 1188 |
| ESO 548-16 | 03 26.0 | –21 20 | 15.6 | Scd | 1.7 | 40 | 1977 |
| NGC 1332 | 03 26.3 | –21 20 | 11.4 | E | 4.2 | 105 | 1383 |
| ESO 548-21 | 03 27.6 | –21 14 | 14.7 | SBd | 2.0 | 50 | 1541 |
| ESO 548-25 | 03 29.0 | –22 09 | 15.0 | SBa | 1.3 | 30 | 1542 |
| NGC 1345 | 03 29.5 | –17 47 | 14.3 | SBc | 1.4 | 35 | 1385 |
| ESO 481-30 | 03 29.6 | –23 21 | 15.5 | Scd | 1.5 | 35 | 1504 |
| NGC 1347 | 03 29.7 | –22 17 | 13.9 | SBc | 1.4 | 35 | 1624 |
| ESO 548-28 | 03 30.6 | –17 56 | 14.0 | S0 | 1.3 | 35 | 1360 |
| ESO 548-29 | 03 30.8 | –21 03 | 14.3 | SBbc | 1.1 | 30 | 1175 |
| NGC 1353 | 03 32.1 | –20 49 | 12.4 | SBb | 3.5 | 85 | 1390 |
| ESO 548-32 | 03 32.3 | –17 43 | 15.8 | SBm | 1.6 | 40 | 1815 |
| ESO 548-33 | 03 32.5 | –18 57 | 14.5 | S0 | 1.3 | 35 | 1552 |
| ESO 548-34 | 03 33.0 | –21 05 | 14.6 | SBc | 1.1 | 30 | 1610 |
| ESO 482-05 | 03 33.0 | –24 08 | 15.2 | SBcd | 2.1 | 50 | 1783 |
| NGC 1357 | 03 33.2 | –13 39 | 12.4 | Sab | 3.2 | 85 | 2018 |
| IC 1952 | 03 33.4 | –23 43 | 13.5 | SBbc | 2.5 | 60 | 1683 |
| IC 1953 | 03 33.7 | –21 29 | 12.7 | SBc | 2.6 | 65 | 1733 |
| NGC 1359 | 03 33.8 | –19 29 | 13.0 | SBm | 2.1 | 55 | 1833 |
| NGC 1362 | 03 33.9 | –20 17 | 14.2 | S0 | 1.2 | 30 | 1085 |
| ESO 548-44 | 03 34.3 | –19 25 | 14.2 | S0 | 1.3 | 35 | 1561 |
| ESO 548-47 | 03 34.7 | –19 02 | 14.1 | S0 | 2.5 | 60 | 1472 |
| NGC 1367 | 03 35.0 | –24 56 | 11.6 | SBa | 5.6 | 140 | 1344 |
| NGC 1370 | 03 35.2 | –20 22 | 13.9 | E | 1.5 | 35 | 933 |
| IC 1962 | 03 35.6 | –21 18 | 14.8 | SBd | 2.5 | 60 | 1670 |
| ESO 482-11 | 03 36.3 | –25 36 | 14.7 | Sbc | 1.4 | 35 | 1469 |
| NGC 1377 | 03 36.7 | –20 54 | 13.8 | S0 | 1.7 | 45 | 1645 |
| NGC 1385 | 03 37.5 | –24 30 | 11.5 | SBc | 3.7 | 90 | 1373 |
| NGC 1383 | 03 37.7 | –18 20 | 13.8 | S0 | 1.7 | 40 | 1828 |
| ESO 482-17 | 03 37.7 | –22 55 | 14.9 | Sab | 1.3 | 30 | 1330 |
| NGC 1390 | 03 37.9 | –19 00 | 14.9 | SBa | 1.3 | 35 | 1078 |
| NGC 1395 | 03 38.5 | –23 02 | 10.7 | E | 5.6 | 140 | 1577 |
| NGC 1398 | 03 38.9 | –26 20 | 10.5 | SB(r)ab | 7.1 | 135 | 1289 |
| NGC 1403 | 03 39.2 | –22 23 | 14.1 | E | 1.3 | 30 | 1751 |
| NGC 1401 | 03 39.4 | –22 43 | 13.7 | S0 | 1.9 | 50 | 1406 |
| NGC 1400 | 03 39.5 | –18 41 | 12.3 | E | 2.3 | 60 | 415 |
| ESO 548-63 | 03 39.6 | –20 01 | 15.1 | Sbc | 1.4 | 35 | 1846 |
| ESO 548-65 | 03 40.0 | –19 22 | 15.3 | Sa | 1.4 | 35 | 1102 |
| IC 343 | 03 40.1 | –18 27 | 14.3 | S0 | 1.4 | 35 | 1730 |
| NGC 1407 | 03 40.2 | –18 35 | 10.9 | E | 5.1 | 125 | 1650 |
| ESO 548-68 | 03 40.3 | –18 56 | 14.3 | E | 1.3 | 35 | 1636 |
| NGC 1412 | 03 40.5 | –26 52 | 14.7 | S0 | 1.4 | 35 | 1675 |
| ESO 548-70 | 03 40.7 | –22 17 | 15.4 | SBcd | 1.6 | 40 | 1615 |
| ESO 482-32 | 03 40.7 | –26 47 | 15.9 | Irr | 1.2 | 30 | 1621 |
| NGC 1415 | 03 40.9 | –22 34 | 12.8 | Sa | 3.3 | 80 | 1451 |
| NGC 1414 | 03 41.0 | –21 43 | 14.6 | SBbc | 1.6 | 40 | 1464 |
| ESO 482-35 | 03 41.2 | –23 50 | 14.2 | SBab | 1.8 | 45 | 1756 |
| NGC 1422 | 03 41.5 | –21 41 | 14.2 | SBab | 2.3 | 55 | 1514 |
| IC 346 | 03 41.7 | –18 16 | 13.9 | S0 | 1.9 | 45 | 1830 |
| ESO 548-79 | 03 41.9 | –18 54 | 14.8 | Sa | 1.1 | 30 | 1914 |
| ESO 548-82 | 03 42.7 | –17 30 | 15.4 | Sbc | 1.1 | 30 | 1590 |
| NGC 1426 | 03 42.8 | –22 06 | 12.7 | E | 2.5 | 60 | 1296 |
| ESO 549-02 | 03 43.0 | –19 01 | 14.9 | SBm | 1.3 | 30 | 988 |
| ESO 549-06 | 03 43.6 | –21 14 | 15.7 | Irr | 1.3 | 30 | 1490 |
| NGC 1439 | 03 44.8 | –21 55 | 12.4 | E | 2.6 | 65 | 1577 |
| NGC 1440 | 03 45.0 | –18 16 | 12.9 | S0 | 2.2 | 55 | 1403 |
| NGC 1438 | 03 45.3 | –23 00 | 13.3 | SBa | 2.0 | 50 | 1438 |
| NGC 1452 | 03 45.4 | –18 38 | 12.9 | Sa | 2.3 | 60 | 1619 |
| ESO 549-18 | 03 48.2 | –21 28 | 13.3 | SBc | 2.5 | 60 | 1473 |
| ESO 482-46 | 03 49.7 | –27 00 | 13.7 | Sc | 3.5 | 90 | 1422 |
| ESO 482-49 | 03 52.4 | –23 03 | 15.3 | Sc | 1.1 | 30 | 1377 |
| NGC 1482 | 03 54.6 | –20 30 | 13.3 | S0 | 2.2 | 55 | 1753 |
See also
References
- ^ "Eridanus Cluster". NASA/IPAC Extragalactic Database (NED). Retrieved 2012-02-25.
- ^ Omar, A.; Dwarakanath, K. S. (March 2005). "GMRT HI Observations of the Eridanus Group of Galaxies I" (PDF). Journal of Astrophysics and Astronomy. 26 (1): 1–33. arXiv:astro-ph/0503536. Bibcode:2005JApA...26....1O. doi:10.1007/BF02702451. S2CID 7451092. Retrieved 2012-02-25.
- ^ Willmer, C. N. A.; Rocardi, P.; da Costa, L. Nicolaci; Pellegrini, P. S. (November 1989). "Studies of nearby poor clusters – The Eridanus group" (PDF). Astronomical Journal. 98 (Nov. 1989): 1531–1541. Bibcode:1989AJ.....98.1531W. doi:10.1086/115236. ISSN 0004-6256. Retrieved 2012-02-25.
- ^ atlasoftheuniverse.com
- Chincarini, G.; Rood, H. J.; Welch, G. A. (March 1975). "A re-analysis of the dynamics of the nearby groups of galaxies". Monthly Notices of the Royal Astronomical Society. 170 (Mar. 1975): 441–445. Bibcode:1975MNRAS.170..441C. doi:10.1093/mnras/170.3.441. A&AA ID. AAA013.160.006.
