The Second Case of a Major Merger Triggering a Starburst in a Green Pea Galaxy
Abstract We have used the Karl G. Jansky Very Large Array (VLA) to map H i 21 cm emission from the Green Pea galaxy GP J1148+2546 at z ≈ 0.0451, only the second measurement of the H i spatial distribution of a Green Pea. The VLA H i 21 cm image, the DECaLS optical image, and Sloan Digital Sky Survey spectroscopy show that GP J1148+2546 has two neighbors, the nearer of which is only ≈17.5 kpc away, and that the H i 21 cm emission extends in an inverted “C” shape around the Green Pea and its companions, with the highest H i column density between the two neighboring galaxies. The starburst in GP J1148+2546 is likely to have been triggered by the ongoing merger with its neighbors, although the velocity field and velocity dispersion images do not show clear merger signatures at the Green Pea location. The H i mass of the Green Pea and its immediate surroundings is (3.58 ± 0.37) × 10 9 M ⊙ , a factor of ≈7.4 lower than the total H i mass of the system of three interacting galaxies, while the H i depletion timescale of GP J1148+2546 is ≈0.69 Gyr, much shorter than that of typical galaxies at z ≈ 0. We detect damped Ly α absorption and Ly α emission from the Green Pea in a Hubble Space Telescope Cosmic Origins Spectrograph spectrum, obtaining a high H i column density, ≈2.0 × 10 21 cm −2 , and a low Ly α escape fraction, ≈0.8%, consistent with the relatively low value (≈5.4) of the ratio O32 ≡ [O iii ] λ 5007 + λ 4959/[O ii ] λ 3727,3729.
Authors
- Sonalika Purkayastha (ORCID: https://orcid.org/0000-0002-3157-7553)
- James E. Rhoads (ORCID: https://orcid.org/0000-0002-1501-454X)
- T. Ghosh (ORCID: https://orcid.org/0000-0003-4454-2875)
- Sangeeta Malhotra (ORCID: https://orcid.org/0000-0002-9226-5350)
- John Pharo (ORCID: https://orcid.org/0000-0003-2249-2539)
- Nissim Kanekar (ORCID: https://orcid.org/0000-0002-9757-7206)
- Sangita Kumari (ORCID: https://orcid.org/0000-0002-3764-9204)
Institutions
- Tata Institute of Fundamental Research (IN)
- Goddard Space Flight Center (US)
- National Centre for Radio Astrophysics (IN)
- Leibniz Institute for Astrophysics Potsdam (DE)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2024-12-01
- DOI
- https://doi.org/10.3847/1538-4357/ad8dd2
- Citations
- 2
- Primary Topic
- Plant Reproductive Biology
- Type
- article
- Field-Weighted Citation Impact
- 0.47
Funders
- National Science Foundation
- U.S. Department of Energy
- National Aeronautics and Space Administration
- University of Pennsylvania
- Ohio State University
- University of Chicago
- University of Portsmouth
- Space Telescope Science Institute
- University College London
- University of Sussex
- Department of Science and Technology, Ministry of Science and Technology, India
- Department of Atomic Energy, Government of India
- Deutsche Forschungsgemeinschaft
- Financiadora de Estudos e Projetos
- University of Illinois at Urbana-Champaign
- Office of Science
- Science and Technology Facilities Council
- Division of Astronomical Sciences
- High Energy Physics
- Integrated Electronics Engineering Center, Binghamton University
- Argonne National Laboratory
- Fermilab
- Lawrence Berkeley National Laboratory
- SLAC National Accelerator Laboratory