Download pdf
Compact object probed by microlensing in the universe: MACHOs, stars, planets?
- 1 St. Paul's School
- 2 Polar Research Institute of China
* Author to whom correspondence should be addressed.
Abstract
Nearly 30% of the components in the universe are dark matter, hitherto, astronomers are still uncertain about their properties. This project attempts to constrain whether dark matter is MACHOs or diffused particles via statistics of microlensing events observed toward quasars, which are the brightest objects in the Universe. The identification of isolated microlensing events enables us to study stellar and planetary objects in distant universes that would be otherwise unobservable. During the research two isolated microlensing events toward quasar J1821 is discovered in the first 25 quasars in our sample. The WISE light curves in W1 and W2 bands are almost identical in magnification, consistent with achromatic variability due to microlensing. The crossing times for the two events are about 2 days and 1.3 days, thus the lenses are probably a star or sub-stellar object. By assuming the lenses are in galaxies of the galactic cluster with a redshift of 0.81 lying in our sight of view to the quasar, calculations of the mass of the lenses as a function of its velocity can be made, yielding a planetary mass or less in the relative velocity dominated by the movements of galaxies. If the superluminous motion of jets in a quasar dominates the relative velocity, stellar masses are derived. The data analysis yielded from the microlensing light curves of J1821 suggests microlensing as a method for astronomers to further study stellar and sub-stellar objects in our Universe.
Keywords
dark matter, microlensing events, redshift, mass of the lenses
[1]. Maoz, D., 2016. Astrophysics in a Nutshell (Vol. 16). Princeton university press.
[2]. Kayser, R., Refsdal, S. and Stabell, R., 1986. Astrophysical applications of gravitational micro-lensing. Astronomy and Astrophysics, 166, pp.36-52.
[3]. Bertone, G. and Hooper, D., 2018. History of dark matter. Reviews of Modern Physics, 90(4), p.045002.
[4]. Perryman, M., 2018. The exoplanet handbook. Cambridge university press.
[5]. Gioia, I.M., Wolter, A., Mullis, C.R., Henry, J.P., Böhringer, H. and Briel, U.G., 2004. RX J1821. 6+ 6827: A cool cluster at z= 0.81 from the ROSAT NEP survey. Astronomy & Astrophysics, 428(3), pp.867-875.
[6]. Gioia, I.M., Henry, J.P., Mullis, C.R., Böhringer, H., Briel, U.G., Voges, W. and Huchra, J.P., 2003. The ROSAT north ecliptic pole survey: The optical identifications. The Astrophysical Journal Supplement Series, 149(1), p.29.
Cite this article
Du,S.;Jiang,P. (2023). Compact object probed by microlensing in the universe: MACHOs, stars, planets?. Theoretical and Natural Science,10,53-63.
Data availability
The datasets used and/or analyzed during the current study will be available from the authors upon reasonable request.
Disclaimer/Publisher's Note
The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of EWA Publishing and/or the editor(s). EWA Publishing and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.
About volume
Volume title: Proceedings of the 2023 International Conference on Mathematical Physics and Computational Simulation
© 2024 by the author(s). Licensee EWA Publishing, Oxford, UK. This article is an open access article distributed under the terms and
conditions of the Creative Commons Attribution (CC BY) license. Authors who
publish this series agree to the following terms:
1. Authors retain copyright and grant the series right of first publication with the work simultaneously licensed under a Creative Commons
Attribution License that allows others to share the work with an acknowledgment of the work's authorship and initial publication in this
series.
2. Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the series's published
version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgment of its initial
publication in this series.
3. Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and
during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See
Open access policy for details).