Haro 2 is a blue compact galaxy in the constellation Ursa Major. The galaxy lies about 120 million light years away from Earth based on redshift independent measurements, which means, given its apparent dimensions, that Haro 2 is approximately 45,000 light years across, while redshift indicates a distance of 70 million light years.[1]
| Haro 2 | |
|---|---|
 Haro 2 by Sloan Digital Sky Survey | |
| Observation data (J2000 epoch) | |
| Constellation | Ursa Major |
| Right ascension | 10h 32m 32.0s[1] |
| Declination | 54° 24′ 02″[1] |
| Redshift | 0.004796 ± 0.000007 [1] |
| Heliocentric radial velocity | 1438 ± 2 km/s[1] |
| Distance | 124 ± 58 Mly (38 ± 18 Mpc)[1] |
| Apparent magnitude (V) | 13.1 |
| Characteristics | |
| Type | Im pec [1] |
| Apparent size (V) | 1.12′ × 0.80′[1] |
| Notable features | Blue compact dwarf |
| Other designations | |
| UGC 5720, Arp 233, MRK 33, MCG +09-17-070, PGC 31141[1] | |
Guillermo Haro first described H2 in a study published in 1956 listing 44 galaxies that were blue.[2] Blue compact galaxies have been found to host large numbers of young massive stars due to a burst of star formation. The galaxy spectrum features emission from Wolf-Rayet stars.[3] The age of the current starburst activity is calculated to be 5.8 ± 1.0 million years.[4]
An outflow of ionised gas around the central HII region forming a shell could be galactic wind created by the starburst activity in the centre of the galaxy. The galaxy has been found to emit Lyman-alpha both from the central HII region and the shell.[5] The expanding shell has also been observed in X-rays with ROSAT, indicating it forms a superbubble.[4] Imaging of CO(2–1) indicates that the shell has entrained molecular gas.[6] The kinematics of the shell suggest that it has an age of 5 to 6 million years.[7]
See also
edit- NGC 3353 - a similar dwarf galaxy
References
edit- ^ a b c d e f g h i "NASA/IPAC Extragalactic Database". Results for UGC 5720. Retrieved 2024-03-26.
- ^ G. Haro (1956). "Preliminary note on blue galaxies with nuclear emission". Astronomical Journal. 1: 178. Bibcode:1956AJ.....61R.178H. doi:10.1086/107409.
- ^ Kunth, D.; Joubert, M. (1 January 1985). "Wolf-Rayet stars in "lazy" galaxies : a statistical approach". Astronomy and Astrophysics. 142: 411–420. Bibcode:1985A&A...142..411K. ISSN 0004-6361.
- ^ a b Summers, L. K.; Stevens, I. R.; Strickland, D. K. (21 October 2001). "The energetics and mass loss of the dwarf starburst Markarian 33". Monthly Notices of the Royal Astronomical Society. 327 (2): 385–396. arXiv:astro-ph/0106475. Bibcode:2001MNRAS.327..385S. doi:10.1046/j.1365-8711.2001.04722.x.
- ^ Lequeux, J.; Kunth, D.; Mas-Hesse, J. M.; Sargent, W. L. W. (1 September 1995). "Galactic wind and Lyman α emission in the blue compact galaxy Haro 2 = MKN 33". Astronomy and Astrophysics. 301: 18. Bibcode:1995A&A...301...18L. ISSN 0004-6361.
- ^ Beck, Sara C; Hsieh, Pei-Ying; Turner, Jean (1 May 2020). "SMA observations of Haro 2: molecular gas around a hot superbubble". Monthly Notices of the Royal Astronomical Society. 494 (1): 1–9. arXiv:1909.04971. doi:10.1093/mnras/staa660.
- ^ Legrand, F.; Kunth, D.; Mas-Hesse, J. M.; Lequeux, J. (1 October 1997). "Evidences for an expanding shell in the blue compact dwarf galaxy Haro 2". Astronomy and Astrophysics. 326: 929–935. arXiv:astro-ph/9706109. Bibcode:1997A&A...326..929L.
External links
edit- Haro 2 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images