Ultradeep Imaging of Nearby Dwarf Irregular Galaxies: Young Objects in the Far Outer Disk
Ultradeep UBVI imaging of 10 nearby (≤7.8 Mpc) noninteracting dwarf irregular galaxies are used to examine their far outer stellar disks. The annulus between 26 mag arcsec ^−2 and 29 mag arcsec ^−2 in the V band is what we define as the far outer disk and is our focus here. Photometry of distinct ob...
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| Language: | English |
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IOP Publishing
2025-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/ade154 |
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| author | Deidre A. Hunter Hong-Xin Zhang Bruce G. Elmegreen Ella R. Castelloe Hannah Michaye Ledford Ishara Nisley Ryuga Hatano |
| author_facet | Deidre A. Hunter Hong-Xin Zhang Bruce G. Elmegreen Ella R. Castelloe Hannah Michaye Ledford Ishara Nisley Ryuga Hatano |
| author_sort | Deidre A. Hunter |
| collection | DOAJ |
| description | Ultradeep UBVI imaging of 10 nearby (≤7.8 Mpc) noninteracting dwarf irregular galaxies are used to examine their far outer stellar disks. The annulus between 26 mag arcsec ^−2 and 29 mag arcsec ^−2 in the V band is what we define as the far outer disk and is our focus here. Photometry of distinct objects in the far outer disks, including far-UV images, is used to determine ages of the objects in order to look for those that are young. In three of the galaxies we find objects with high-confidence ages ≤30 Myr. These objects are too young to have scattered into the far outer disk from the central regions. Therefore, they likely formed in situ. How star-forming gas clouds formed in the extreme environment of the outer stellar disks of dwarfs is a primary unanswered question. |
| format | Article |
| id | doaj-art-7cb0fd4aa4404e2bb7cff2f1f2d0e6e8 |
| institution | Matheson Library |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj-art-7cb0fd4aa4404e2bb7cff2f1f2d0e6e82025-07-09T16:40:28ZengIOP PublishingThe Astronomical Journal1538-38812025-01-0117027610.3847/1538-3881/ade154Ultradeep Imaging of Nearby Dwarf Irregular Galaxies: Young Objects in the Far Outer DiskDeidre A. Hunter0https://orcid.org/0000-0002-3322-9798Hong-Xin Zhang1https://orcid.org/0000-0003-1632-2541Bruce G. Elmegreen2https://orcid.org/0000-0002-1723-6330Ella R. Castelloe3Hannah Michaye Ledford4Ishara Nisley5Ryuga Hatano6Lowell Observatory , 1400 West Mars Hill Road, Flagstaff, AZ 86001, USADepartment of Astronomy, University of Science and Technology of China , Hefei, Anhui, People’s Republic of ChinaKatonah , NY 10536, USALowell Observatory , 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA; Department of Astronomy and Planetary Science, Northern Arizona University , 527 S. Beaver Street, Flagstaff, AZ 86011-6010, USALowell Observatory , 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology , Cambridge, MA 02139, USALowell Observatory , 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology , Cambridge, MA 02139, USALowell Observatory , 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology , Cambridge, MA 02139, USAUltradeep UBVI imaging of 10 nearby (≤7.8 Mpc) noninteracting dwarf irregular galaxies are used to examine their far outer stellar disks. The annulus between 26 mag arcsec ^−2 and 29 mag arcsec ^−2 in the V band is what we define as the far outer disk and is our focus here. Photometry of distinct objects in the far outer disks, including far-UV images, is used to determine ages of the objects in order to look for those that are young. In three of the galaxies we find objects with high-confidence ages ≤30 Myr. These objects are too young to have scattered into the far outer disk from the central regions. Therefore, they likely formed in situ. How star-forming gas clouds formed in the extreme environment of the outer stellar disks of dwarfs is a primary unanswered question.https://doi.org/10.3847/1538-3881/ade154Dwarf irregular galaxiesStar formationGalaxy evolution |
| spellingShingle | Deidre A. Hunter Hong-Xin Zhang Bruce G. Elmegreen Ella R. Castelloe Hannah Michaye Ledford Ishara Nisley Ryuga Hatano Ultradeep Imaging of Nearby Dwarf Irregular Galaxies: Young Objects in the Far Outer Disk The Astronomical Journal Dwarf irregular galaxies Star formation Galaxy evolution |
| title | Ultradeep Imaging of Nearby Dwarf Irregular Galaxies: Young Objects in the Far Outer Disk |
| title_full | Ultradeep Imaging of Nearby Dwarf Irregular Galaxies: Young Objects in the Far Outer Disk |
| title_fullStr | Ultradeep Imaging of Nearby Dwarf Irregular Galaxies: Young Objects in the Far Outer Disk |
| title_full_unstemmed | Ultradeep Imaging of Nearby Dwarf Irregular Galaxies: Young Objects in the Far Outer Disk |
| title_short | Ultradeep Imaging of Nearby Dwarf Irregular Galaxies: Young Objects in the Far Outer Disk |
| title_sort | ultradeep imaging of nearby dwarf irregular galaxies young objects in the far outer disk |
| topic | Dwarf irregular galaxies Star formation Galaxy evolution |
| url | https://doi.org/10.3847/1538-3881/ade154 |
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