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The Past, Present, and Groundbreaking Future of OH Megamaser Discoveries

Published online by Cambridge University Press:  07 February 2024

Hayley Roberts*
Affiliation:
Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Science, University of Colorado, 389 UCB, Boulder, CO 80309-0389, USA.
Jeremy Darling
Affiliation:
Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Science, University of Colorado, 389 UCB, Boulder, CO 80309-0389, USA.
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Abstract

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OH megamasers (OHMs) are luminous masers found in (ultra-)luminous infrared galaxies ([U]LIRGs). OHMs are signposts of major gas-rich mergers associated with some of the most extreme star forming regions in our universe. The dominant OH masing line, occurring at 1667 MHz, can spoof the 1420 MHz neutral hydrogen (HI) line in untargeted HI emission line surveys. While only ∼120 OHMs are currently known, HI surveys on next-generation radio telescopes, such as the Square Kilometre Array (SKA) and its precursors, will detect unprecedented numbers of OHMs. This surge in detections will not only fundamentally change what we know about the OHM population, but will also unlock our ability to implement OHMs as tracers of major mergers and extreme star formation on cosmic scales. Here we present predictions for the number of OHMs that will be detected by these surveys. We also present our novel methods for identifying these interlopers using a k-Nearest Neighbors machine learning algorithm. Preliminary data from HI surveys on precursor SKA telescopes is being used to vet and strengthen these methods as well as give us a first look at a new era in OHM science. From a detection of one of the most luminous OHMs to the discovery of a megamaser at a record-shattering redshift, these new sources are glimpses into how our understanding of the known OHM population will soon be expanding and shifting rapidly and how they will influence our understanding of galaxy evolution.

Type
Contributed Paper
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2024. Published by Cambridge University Press on behalf of International Astronomical Union

References

Baan, W. A., Rhoads, J., Fisher, K., et al. 1992, ApJL, 396, L99 10.1086/186526CrossRefGoogle Scholar
Baan, W. A., Haschick, A. D., & Henkel, C. 1989, ApJ, 346, 680 10.1086/168050CrossRefGoogle Scholar
Briggs, F. H. 1998, A&A, 336, 815 Google Scholar
Darling, J. & Giovanelli, R. 2006, AJ, 132, 2596 10.1086/508513CrossRefGoogle Scholar
Darling, J. 2007, ApJL, 669, L9 10.1086/523756CrossRefGoogle Scholar
Darling, J. & Giovanelli, R. 2002, AJ, 124, 100 10.1086/341166CrossRefGoogle Scholar
Duffy, A. R., Meyer, M. J., Staveley-Smith, L., et al. 2012, MNRAS, 426, 3385 10.1111/j.1365-2966.2012.21987.xCrossRefGoogle Scholar
Glowacki, M., Collier, J. D., Kazemi-Moridani, A., et al. 2022, ApJL, 931, L7 10.3847/2041-8213/ac63b0CrossRefGoogle Scholar
Haynes, M. P., Giovanelli, R., Martin, A. M., et al. 2011, AJ, 142, 170 10.1088/0004-6256/142/5/170CrossRefGoogle Scholar
Haynes, M. P., Giovanelli, R., Kent, B. R., et al. 2018, ApJ, 861, 49 10.3847/1538-4357/aac956CrossRefGoogle Scholar
Hess, K. M., Roberts, H., Dénes, H., et al. 2021, A&A, 647, A193 Google Scholar
Lo, K. Y. 2005, ARA&A, 43, 625 Google Scholar
Lockett, P. & Elitzur, M. 2008, ApJ, 677, 985 10.1086/533429CrossRefGoogle Scholar
McBride, J. & Heiles, C. 2013, ApJ, 763, 8 10.1088/0004-637X/763/1/8CrossRefGoogle Scholar
Morganti, R., de Zeeuw, P. T., Oosterloo, T. A., et al. 2006, MNRAS, 371, 157 10.1111/j.1365-2966.2006.10681.xCrossRefGoogle Scholar
Roberts, H., Darling, J., & Baker, A. J. 2021, ApJ, 911, 38 10.3847/1538-4357/abe944CrossRefGoogle Scholar
Roberts, H., Darling, J., Hess, K. M. & Baker, A. J. in prep., ApJ Google Scholar
Robishaw, T., Quataert, E., & Heiles, C. 2008, ApJ, 680, 981 10.1086/588031CrossRefGoogle Scholar
Suess, K. A., Darling, J., Haynes, M. P., et al. 2016, MNRAS, 459, 220 10.1093/mnras/stw666CrossRefGoogle Scholar
Willett, K. W., Darling, J., Spoon, H. W. W., et al. 2011, ApJ, 730, 56 10.1088/0004-637X/730/1/56CrossRefGoogle Scholar