The Microlensing Event Rate and Optical Depth from MOA-II 9 Yr Survey Toward the Galactic Bulge

Nunota, Kansuke; Sumi, Takahiro; Koshimoto, Naoki; Rattenbury, Nicholas J.; Abe, Fumio; Barry, Richard; Bennett, David P.; Bhattacharya, Aparna; Fukui, Akihiko; Hamada, Ryusei; Hamada, Shunya; Hamasaki, Naoto; Hirao, Yuki; Silva, Stela Ishitani; Itow, Yoshitaka; Matsubara, Yutaka; Miyazaki, Shota; Muraki, Yasushi; Nagai, Tsutsumi; Olmschenk, Greg; Ranc, Clement; Satoh, Yuki K.; Suzuki, Daisuke; Tristram, Paul J.; Vandorou, Aikaterini; Yama, Hibiki

doi:https://doi.org/10.3847/1538-4357/ada352

The Microlensing Event Rate and Optical Depth from MOA-II 9 Yr Survey Toward the Galactic Bulge

Nunota, Kansuke; Sumi, Takahiro; Koshimoto, Naoki et al.

Astrophysical Journal, 2025, 979(2), 123

Number of Access:1,651（2025-08-23 21:57 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/101061

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Title	The Microlensing Event Rate and Optical Depth from MOA-II 9 Yr Survey Toward the Galactic Bulge
Creator	CreatorName Nunota, Kansuke
	NRID 1000030432214 1000030432214 researchmap permalink read0139558 read0139558 Scopus Author ID 55573890400 55573890400 CreatorName Sumi, Takahiro
	CreatorName Koshimoto, Naoki
	CreatorName Rattenbury, Nicholas J.
	NRID 1000080184224 1000080184224 CreatorName Abe, Fumio
	CreatorName Barry, Richard
	CreatorName Bennett, David P.
	CreatorName Bhattacharya, Aparna
	NRID 1000060632049 1000060632049 CreatorName Fukui, Akihiko
	CreatorName Hamada, Ryusei
	CreatorName Hamada, Shunya
	CreatorName Hamasaki, Naoto
	CreatorName Hirao, Yuki
	CreatorName Silva, Stela Ishitani
	NRID 1000050272521 1000050272521 CreatorName Itow, Yoshitaka
	NRID 1000080202323 1000080202323 CreatorName Matsubara, Yutaka
	NRID 1000010975973 1000010975973 CreatorName Miyazaki, Shota
	NRID 1000070013430 1000070013430 CreatorName Muraki, Yasushi
	CreatorName Nagai, Tsutsumi
	CreatorName Olmschenk, Greg
	CreatorName Ranc, Clement
	CreatorName Satoh, Yuki K.
	NRID 1000060807717 1000060807717 ORCID 0000-0002-5843-9433 0000-0002-5843-9433 researchmap permalink dsuzuki0214 dsuzuki0214 Scopus Author ID 55702463200 55702463200 CreatorName Suzuki, Daisuke
	CreatorName Tristram, Paul J.
	CreatorName Vandorou, Aikaterini
	CreatorName Yama, Hibiki
Description	Nunota K., Sumi T., Koshimoto N., et al. The Microlensing Event Rate and Optical Depth from MOA-II 9 Yr Survey Toward the Galactic Bulge. Astrophysical Journal 979, 123 (2025); https://doi.org/10.3847/1538-4357/ada352.
Abstract	We present measurements of the microlensing optical depth and event rate toward the Galactic bulge using the data set from the 2006 to 2014 MOA-II survey, which covers 22 bulge fields spanning ∼42 deg2 between −5° < l < 10° and −7° < b < −1°. In the central region with ∣l∣ < 5°, we estimate an optical depth of τ = [ 1.75 ± 0.04 ] × 1 0 − 6 exp [ ( 0.34 ± 0.02 ) ( 3 ∘ − ∣ b ∣ ) ] and an event rate of Γ = [16.08 ± 0.28] × 10−6 exp [ ( 0.44 ± 0.02 ) ( 3 ∘ − ∣ b ∣ ) ] star − 1 yr − 1 using a sample consisting of 3525 microlensing events, with Einstein radius crossing times of tE < 760 days and a source star magnitude of Is < 21.4 mag. We confirm our results are consistent with the latest measurements from the OGLE-IV 8 yr data set. We find our result is inconsistent with a prediction based on Galactic models, especially in the central region with ∣b∣ < 3°. These results can be used to improve the Galactic bulge model, and more central regions can be further elucidated by upcoming microlensing experiments, such as the PRime-focus Infrared Microlensing Experiment and Nancy Grace Roman Space Telescope.
Publisher	Institute of Physics
Source Title	Astrophysical Journal
Volume (Issue)	979(2)
Page	123
Date of Issued	2025-02-01
Language	English
Handle URL	https://hdl.handle.net/11094/101061
PISSN	0004637X
eISSN	15384357
Relation.isIdenticalTo	DOI (Publisher Version) https://doi.org/10.3847/1538-4357/ada352
Access Rights	open access
CopyRight	This article is licensed under a Creative Commons Attribution 4.0 International License.
oaire:version	Version of Record
Category	学術雑誌論文 Journal Article

Resource Type	journal article
Local Type	Journal Article
DCMI Type	Text
DCTERMS.bibliographicCitation	Astrophysical Journal. 2025, 979(2), p. 123
DC.title	The Microlensing Event Rate and Optical Depth from MOA-II 9 Yr Survey Toward the Galactic Bulge
DC.creator	Nunota, Kansuke
	Sumi, Takahiro
	Koshimoto, Naoki
	Rattenbury, Nicholas J.
	Abe, Fumio
	Barry, Richard
	Bennett, David P.
	Bhattacharya, Aparna
	Fukui, Akihiko
	Hamada, Ryusei
	Hamada, Shunya
	Hamasaki, Naoto
	Hirao, Yuki
	Silva, Stela Ishitani
	Itow, Yoshitaka
	Matsubara, Yutaka
	Miyazaki, Shota
	Muraki, Yasushi
	Nagai, Tsutsumi
	Olmschenk, Greg
	Ranc, Clement
	Satoh, Yuki K.
	Suzuki, Daisuke
	Tristram, Paul J.
	Vandorou, Aikaterini
	Yama, Hibiki
DC.publisher	Institute of Physics
DC.language' scheme='DCTERMS.RFC1766	English
DC.type' scheme='DCTERMS.DCMIType	Text
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2025-02-01
DC.identifier	https://doi.org/10.3847/1538-4357/ada352
DC.description	Nunota K., Sumi T., Koshimoto N., et al. The Microlensing Event Rate and Optical Depth from MOA-II 9 Yr Survey Toward the Galactic Bulge. Astrophysical Journal 979, 123 (2025); https://doi.org/10.3847/1538-4357/ada352.
DCTERMS.abstract	We present measurements of the microlensing optical depth and event rate toward the Galactic bulge using the data set from the 2006 to 2014 MOA-II survey, which covers 22 bulge fields spanning ∼42 deg2 between −5° < l < 10° and −7° < b < −1°. In the central region with ∣l∣ < 5°, we estimate an optical depth of τ = [ 1.75 ± 0.04 ] × 1 0 − 6 exp [ ( 0.34 ± 0.02 ) ( 3 ∘ − ∣ b ∣ ) ] and an event rate of Γ = [16.08 ± 0.28] × 10−6 exp [ ( 0.44 ± 0.02 ) ( 3 ∘ − ∣ b ∣ ) ] star − 1 yr − 1 using a sample consisting of 3525 microlensing events, with Einstein radius crossing times of tE < 760 days and a source star magnitude of Is < 21.4 mag. We confirm our results are consistent with the latest measurements from the OGLE-IV 8 yr data set. We find our result is inconsistent with a prediction based on Galactic models, especially in the central region with ∣b∣ < 3°. These results can be used to improve the Galactic bulge model, and more central regions can be further elucidated by upcoming microlensing experiments, such as the PRime-focus Infrared Microlensing Experiment and Nancy Grace Roman Space Telescope.
DC.rights	This article is licensed under a Creative Commons Attribution 4.0 International License.
DC.format	101061
citation_title	The Microlensing Event Rate and Optical Depth from MOA-II 9 Yr Survey Toward the Galactic Bulge
citation_author	Nunota, Kansuke
	Sumi, Takahiro
	Koshimoto, Naoki
	Rattenbury, Nicholas J.
	Abe, Fumio
	Barry, Richard
	Bennett, David P.
	Bhattacharya, Aparna
	Fukui, Akihiko
	Hamada, Ryusei
	Hamada, Shunya
	Hamasaki, Naoto
	Hirao, Yuki
	Silva, Stela Ishitani
	Itow, Yoshitaka
	Matsubara, Yutaka
	Miyazaki, Shota
	Muraki, Yasushi
	Nagai, Tsutsumi
	Olmschenk, Greg
	Ranc, Clement
	Satoh, Yuki K.
	Suzuki, Daisuke
	Tristram, Paul J.
	Vandorou, Aikaterini
	Yama, Hibiki
citation_publisher	Institute of Physics
citation_language	English
citation_date	2025-02-01
citation_journal_title	Astrophysical Journal
citation_volume	979
citation_issue	2
citation_firstpage	123
citation_doi	https://doi.org/10.3847/1538-4357/ada352
citation_public_url	https://hdl.handle.net/11094/101061

The Microlensing Event Rate and Optical Depth from MOA-II 9 Yr Survey Toward the Galactic Bulge

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