Microlensing Events in Five Years of Photometry from the Zwicky Transient Facility
Microlensing has a unique advantage for detecting dark objects in the Milky Way, such as free-floating planets, neutron stars, and stellar-mass black holes. Most microlensing surveys focus on the Galactic bulge, where higher stellar density leads to a higher event rate. However, microlensing events...
Saved in:
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2024-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/ad94e7 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1846107499974885376 |
|---|---|
| author | Ruocheng Zhai Antonio C. Rodriguez Shude Mao Casey Y. Lam Eric C. Bellm Josiah Purdum Frank J. Masci Avery Wold |
| author_facet | Ruocheng Zhai Antonio C. Rodriguez Shude Mao Casey Y. Lam Eric C. Bellm Josiah Purdum Frank J. Masci Avery Wold |
| author_sort | Ruocheng Zhai |
| collection | DOAJ |
| description | Microlensing has a unique advantage for detecting dark objects in the Milky Way, such as free-floating planets, neutron stars, and stellar-mass black holes. Most microlensing surveys focus on the Galactic bulge, where higher stellar density leads to a higher event rate. However, microlensing events in the Galactic plane have closer lenses and longer timescales, which leads to a greater chance of measuring microlens parallax, providing an additional constraint on the mass of the lens. This work searches for microlensing events in Zwicky Transient Facility (ZTF) Data Release 17 from 2018 to 2023 in the Galactic plane region. We find 124 high-confidence microlensing events and 54 possible events, all available online (see footnote 11). Thus, with 2 yr of additional ZTF data in DR17, we have more than doubled the number of microlensing events (60) found in the previous 3 yr DR5 search. In the event selection, we use the efficient EventFinder algorithm to detect microlensing signals, which could be used for large data sets such as future ZTF data releases or data from the Rubin Observatory Legacy Survey of Space and Time. Using detection efficiencies of ZTF fields obtained from catalog-level simulations, we calculate the mean Einstein timescale to be 〈 t _E 〉 = 51.7 ± 3.3 days, smaller than previous results of the Galactic plane but within 1.5 σ . We also calculate optical depths and event rates, although some caution is needed due to the use of visual inspection when creating our final sample. Spectroscopy of three possible candidates confirms their microlensing nature. |
| format | Article |
| id | doaj-art-8c927840b6854e1d8a5dd1667868c20b |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-8c927840b6854e1d8a5dd1667868c20b2024-12-26T09:32:56ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0197817610.3847/1538-4357/ad94e7Microlensing Events in Five Years of Photometry from the Zwicky Transient FacilityRuocheng Zhai0https://orcid.org/0009-0004-1650-3494Antonio C. Rodriguez1https://orcid.org/0000-0003-4189-9668Shude Mao2https://orcid.org/0000-0001-8317-2788Casey Y. Lam3https://orcid.org/0000-0002-6406-1924Eric C. Bellm4https://orcid.org/0000-0001-8018-5348Josiah Purdum5https://orcid.org/0000-0003-1227-3738Frank J. Masci6https://orcid.org/0000-0002-8532-9395Avery Wold7https://orcid.org/0000-0002-9998-6732Department of Astronomy, California Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125, USA ; ruocheng.zhai@gmail.com; Department of Astronomy, Tsinghua University , Beijing 100084, People's Republic of ChinaDepartment of Astronomy, California Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125, USA ; ruocheng.zhai@gmail.comDepartment of Astronomy, Tsinghua University , Beijing 100084, People's Republic of ChinaObservatories of the Carnegie Institution for Science , 813 Santa Barbara Street, Pasadena, CA 91101, USADIRAC Institute, Department of Astronomy, University of Washington , 3910 15th Avenue NE, Seattle, WA 98195, USACaltech Optical Observatories, California Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125, USAIPAC, California Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125, USAIPAC, California Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125, USAMicrolensing has a unique advantage for detecting dark objects in the Milky Way, such as free-floating planets, neutron stars, and stellar-mass black holes. Most microlensing surveys focus on the Galactic bulge, where higher stellar density leads to a higher event rate. However, microlensing events in the Galactic plane have closer lenses and longer timescales, which leads to a greater chance of measuring microlens parallax, providing an additional constraint on the mass of the lens. This work searches for microlensing events in Zwicky Transient Facility (ZTF) Data Release 17 from 2018 to 2023 in the Galactic plane region. We find 124 high-confidence microlensing events and 54 possible events, all available online (see footnote 11). Thus, with 2 yr of additional ZTF data in DR17, we have more than doubled the number of microlensing events (60) found in the previous 3 yr DR5 search. In the event selection, we use the efficient EventFinder algorithm to detect microlensing signals, which could be used for large data sets such as future ZTF data releases or data from the Rubin Observatory Legacy Survey of Space and Time. Using detection efficiencies of ZTF fields obtained from catalog-level simulations, we calculate the mean Einstein timescale to be 〈 t _E 〉 = 51.7 ± 3.3 days, smaller than previous results of the Galactic plane but within 1.5 σ . We also calculate optical depths and event rates, although some caution is needed due to the use of visual inspection when creating our final sample. Spectroscopy of three possible candidates confirms their microlensing nature.https://doi.org/10.3847/1538-4357/ad94e7Milky Way diskGravitational microlensing |
| spellingShingle | Ruocheng Zhai Antonio C. Rodriguez Shude Mao Casey Y. Lam Eric C. Bellm Josiah Purdum Frank J. Masci Avery Wold Microlensing Events in Five Years of Photometry from the Zwicky Transient Facility The Astrophysical Journal Milky Way disk Gravitational microlensing |
| title | Microlensing Events in Five Years of Photometry from the Zwicky Transient Facility |
| title_full | Microlensing Events in Five Years of Photometry from the Zwicky Transient Facility |
| title_fullStr | Microlensing Events in Five Years of Photometry from the Zwicky Transient Facility |
| title_full_unstemmed | Microlensing Events in Five Years of Photometry from the Zwicky Transient Facility |
| title_short | Microlensing Events in Five Years of Photometry from the Zwicky Transient Facility |
| title_sort | microlensing events in five years of photometry from the zwicky transient facility |
| topic | Milky Way disk Gravitational microlensing |
| url | https://doi.org/10.3847/1538-4357/ad94e7 |
| work_keys_str_mv | AT ruochengzhai microlensingeventsinfiveyearsofphotometryfromthezwickytransientfacility AT antoniocrodriguez microlensingeventsinfiveyearsofphotometryfromthezwickytransientfacility AT shudemao microlensingeventsinfiveyearsofphotometryfromthezwickytransientfacility AT caseyylam microlensingeventsinfiveyearsofphotometryfromthezwickytransientfacility AT ericcbellm microlensingeventsinfiveyearsofphotometryfromthezwickytransientfacility AT josiahpurdum microlensingeventsinfiveyearsofphotometryfromthezwickytransientfacility AT frankjmasci microlensingeventsinfiveyearsofphotometryfromthezwickytransientfacility AT averywold microlensingeventsinfiveyearsofphotometryfromthezwickytransientfacility |