IC 485

IC 485 is a spiral galaxy located in the constellation of Gemini, located 375 million light years from Earth. It was discovered by the Austrian astronomer, Rudolf Spitaler on March 6, 1891.^[1] It has an estimated diameter of 1.35' x 0.32' arcmin, meaning the galaxy is about 135,000 light years across.^[2]

IC 485
IC 485 captured by SDSS
Observation data (J2000 epoch)
Constellation	Gemini
Right ascension	08h 00m 19.75s
Declination	+26° 42′ 04.99″
Redshift	0.027827
Heliocentric radial velocity	8,342 km/s
Distance	375 Mly (114.97 Mpc)
Apparent magnitude (V)	0.13
Apparent magnitude (B)	0.17
Characteristics
Type	Sa, AGN
Size	135,000 ly
Apparent size (V)	1.35' x 0.32'
Other designations
UGC 4156, PGC 22443, IRAS 07572+2650

IC 485 is a candidate disc-maser galaxy.^[3] It has a projected distance of 122.0 ± 8.5 megaparsecs.^[4][5] The morphology classification of the galaxy is Sa, and it has a low luminous active galactic nucleus (AGN) of L_X ~ 5 x 10⁴² erg s⁻¹. The AGN activity of IC 485 has been debated. It is either classified a LINER^[6][5] or a Seyfert type II galaxy. But its high X-ray luminosity seems to confirm the latter.^[7]

Using the Karl G. Jansky Very Large Array observations, a team of astronomers led by Jeremy Darling discovered a H₂O maser containing a broad multi-component. The maser of IC 485 has a peak flux of 80 mJy with an isotopic luminosity of L_iso = (868 ± 46)L_Θ.^[7][8] According to Darling, he was also able to find a faint unresolved radio source with its angular resolution measured as 90 milliarcseconds ≈ 50 parsecs.^[7]

In 2022, the galaxy was further studied by another team of astronomers. They discovered, it has two other 22 GHz H₂O maser modules with a velocity separation of 472 km s⁻¹. One is located in the central nuclear region while the other is at a redshifted velocity. Based on estimations on its connection with an edge-on disc, IC 485 has a mass of M_BH ~ 1.2 x 10⁷ M_Θ. According to estimation of its black hole, the galaxy has a core luminosity of 1 x 10³⁶ - 5 x 10³⁷ erg s⁻¹.^[7]

References

1. "Index Catalog Objects: IC 450 - 499". cseligman.com. Retrieved 2024-09-20.
2. "Your NED Search Results". ned.ipac.caltech.edu. Retrieved 2024-09-20.
3. Ladu, Elisabetta; Tarchi, Andrea; Castangia, Paola; Surcis, Gabriele; Braatz, James A.; Panessa, Francesca; Pesce, Dominic (2024-01-01). "IC 485 : A candidate for a new disk-maser galaxy". Cosmic Masers: Proper Motion Toward the Next-Generation Large Projects. 380: 45–49. Bibcode:2024IAUS..380...45L. doi:10.1017/S174392132300248X.
4. Kamali, F.; Henkel, C.; Brunthaler, A.; Impellizzeri, C. M. V.; Menten, K. M.; Braatz, J. A.; Greene, J. E.; Reid, M. J.; Condon, J. J.; Lo, K. Y.; Kuo, C. Y.; Litzinger, E.; Kadler, M. (September 2017). "Radio continuum of galaxies with H₂O megamaser disks: 33 GHz VLA data". Astronomy & Astrophysics. 605: A84. arXiv:1706.02699. Bibcode:2017A&A...605A..84K. doi:10.1051/0004-6361/201730899. ISSN 0004-6361.
5. "IC 485: a LINER galaxy with an elusive accretion disc! | EVLBI". www.evlbi.org. Retrieved 2024-09-20.
6. Liu, Xin; Shen, Yue; Strauss, Michael A.; Hao, Lei (2011-08-01). "Active Galactic Nucleus Pairs from the Sloan Digital Sky Survey. I. The Frequency on ~5-100 kpc Scales". The Astrophysical Journal. 737 (2): 101. arXiv:1104.0950. Bibcode:2011ApJ...737..101L. doi:10.1088/0004-637X/737/2/101. ISSN 0004-637X.
7. Ladu, E.; Tarchi, A.; Castangia, P.; Surcis, G.; Braatz, J. A.; Panessa, F.; Pesce, D. W. (2024-02-01). "IC 485: A new candidate disc-maser galaxy at ∼100 Mpc - Milliarcsecond resolution study of the galaxy nucleus and the H2O megamaser". Astronomy & Astrophysics. 682: A25. arXiv:2310.08998. doi:10.1051/0004-6361/202347795. ISSN 0004-6361.
8. Darling, Jeremy (March 2017). "How to Detect Inclined Water Maser Disks (and Possibly Measure Black Hole Masses)". The Astrophysical Journal. 837 (2): 100. arXiv:1702.06545. Bibcode:2017ApJ...837..100D. doi:10.3847/1538-4357/aa6114. ISSN 0004-637X.