Linking UV spectral properties of MUSE Ly-alpha emitters at z>3 to Lyman continuum escape
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| Autores principales: | , , , , , , , , |
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| Formato: | Preprint |
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2023
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| _version_ | 1866929201630674944 |
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| author | Kramarenko, I. G. Kerutt, J. Verhamme, A. Oesch, P. A. Barrufet, L. Matthee, J. Kusakabe, H. Goovaerts, I. Thai, T. T. |
| author_facet | Kramarenko, I. G. Kerutt, J. Verhamme, A. Oesch, P. A. Barrufet, L. Matthee, J. Kusakabe, H. Goovaerts, I. Thai, T. T. |
| contents | The physical conditions giving rise to high escape fractions of ionizing radiation (LyC $f_{\rm{esc}}$) in star-forming galaxies - most likely protagonists of cosmic reionization - are not yet fully understood. Using the VLT/MUSE observations of ~1400 Ly$α$ emitters at 2.9 < z < 6.7, we compare stacked rest-frame UV spectra of candidates for LyC leakers and non-leakers selected based on their Ly$α$ profiles. We find that the stacks of potential LyC leakers, i.e. galaxies with narrow, symmetric Ly$α$ profiles with small peak separation, generally show (i) strong nebular OIII]1666, [SiIII]1883, and [CIII]1907+CIII]1909 emission, indicating a high-ionization state of the interstellar medium (ISM); (ii) high equivalent widths of HeII1640 (~1-3 A), suggesting the presence of hard ionizing radiation fields; (iii) SiII*1533 emission, revealing substantial amounts of neutral hydrogen off the line of sight; (iv) high CIV1548,1550 to [CIII]1907+CIII]1909 ratios (CIV/CIII] > 0.75), signalling the presence of low column density channels in the ISM. In contrast, the stacks with broad, asymmetric Ly$α$ profiles with large peak separation show weak nebular emission lines, low HeII1640 equivalent widths (<1 A), and low CIV/CIII] (<0.25), implying low-ionization states and high-neutral hydrogen column densities. Our results suggest that CIV/CIII] might be sensitive to the physical conditions that govern LyC photon escape, providing a promising tool for identification of ionizing sources among star-forming galaxies in the epoch of reionization. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2305_07044 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Linking UV spectral properties of MUSE Ly-alpha emitters at z>3 to Lyman continuum escape Kramarenko, I. G. Kerutt, J. Verhamme, A. Oesch, P. A. Barrufet, L. Matthee, J. Kusakabe, H. Goovaerts, I. Thai, T. T. Astrophysics of Galaxies The physical conditions giving rise to high escape fractions of ionizing radiation (LyC $f_{\rm{esc}}$) in star-forming galaxies - most likely protagonists of cosmic reionization - are not yet fully understood. Using the VLT/MUSE observations of ~1400 Ly$α$ emitters at 2.9 < z < 6.7, we compare stacked rest-frame UV spectra of candidates for LyC leakers and non-leakers selected based on their Ly$α$ profiles. We find that the stacks of potential LyC leakers, i.e. galaxies with narrow, symmetric Ly$α$ profiles with small peak separation, generally show (i) strong nebular OIII]1666, [SiIII]1883, and [CIII]1907+CIII]1909 emission, indicating a high-ionization state of the interstellar medium (ISM); (ii) high equivalent widths of HeII1640 (~1-3 A), suggesting the presence of hard ionizing radiation fields; (iii) SiII*1533 emission, revealing substantial amounts of neutral hydrogen off the line of sight; (iv) high CIV1548,1550 to [CIII]1907+CIII]1909 ratios (CIV/CIII] > 0.75), signalling the presence of low column density channels in the ISM. In contrast, the stacks with broad, asymmetric Ly$α$ profiles with large peak separation show weak nebular emission lines, low HeII1640 equivalent widths (<1 A), and low CIV/CIII] (<0.25), implying low-ionization states and high-neutral hydrogen column densities. Our results suggest that CIV/CIII] might be sensitive to the physical conditions that govern LyC photon escape, providing a promising tool for identification of ionizing sources among star-forming galaxies in the epoch of reionization. |
| title | Linking UV spectral properties of MUSE Ly-alpha emitters at z>3 to Lyman continuum escape |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2305.07044 |