Discovery of a radio galaxy at z = 5.72
We report the discovery of the most distant radio galaxy to date, TGSS J1530+1049 at a redshift of z = 5.72, close to the presumed end of the Epoch of Reionization. The radio galaxy was selected from the TGSS ADR1 survey at 150 MHz for having an ultra-steep spectral index, a1.4 GHz150 MHz = -1.4 and...
| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Journal Article |
| Published: |
Oxford University Press
2018
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| Online Access: | http://hdl.handle.net/20.500.11937/74058 |
| _version_ | 1848763168884523008 |
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| author | Saxena, A. Marinello, M. Overzier, R. Best, P. Röttgering, H. Duncan, K. Prandoni, I. Pentericci, L. Magliocchetti, M. Paris, D. Cusano, F. Marchi, F. Intema, Hubertus Miley, G. |
| author_facet | Saxena, A. Marinello, M. Overzier, R. Best, P. Röttgering, H. Duncan, K. Prandoni, I. Pentericci, L. Magliocchetti, M. Paris, D. Cusano, F. Marchi, F. Intema, Hubertus Miley, G. |
| author_sort | Saxena, A. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We report the discovery of the most distant radio galaxy to date, TGSS J1530+1049 at a redshift of z = 5.72, close to the presumed end of the Epoch of Reionization. The radio galaxy was selected from the TGSS ADR1 survey at 150 MHz for having an ultra-steep spectral index, a1.4 GHz150 MHz = -1.4 and a compact morphology obtained using VLA imaging at 1.4 GHz. No optical or infrared counterparts for the radio source were found in publicly available sky surveys. Follow-up optical spectroscopy at the radio position using GMOS on Gemini North revealed the presence of a single emission line. We identify this line as Lyman alpha at z = 5.72, because of its asymmetric line profile, the absence of other optical/UV lines in the spectrum, and a high equivalent width. With an Lya luminosity of 5.7 × 1042 erg s-1 and an FWHM of 370 km s-1, TGSS J1530+1049 is comparable to 'non-radio' Lyman alpha emitters (LAEs) at a similar redshift. However, with a radio luminosity of log L150MHz = 29.1 W Hz-1 and a deconvolved physical size 3.5 kpc, its radio properties are similar to other known radio galaxies at z > 4. Subsequent J and K band imaging using LUCI on the Large Binocular Telescope resulted in non-detection of the host galaxy down to 3s limits of J > 24.4 and K > 22.4 (Vega). The K band limit is consistent withz > 5 from the K-z relation for radio galaxies and helps rule out low redshifts. The stellar mass limit derived using simple stellar population models is Mstars < 1010.5 M?. Its relatively low stellar mass and small radio and Lya sizes suggest that TGSS J1530+1049 may be a radio galaxy in an early phase of its evolution. |
| first_indexed | 2025-11-14T10:59:11Z |
| format | Journal Article |
| id | curtin-20.500.11937-74058 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T10:59:11Z |
| publishDate | 2018 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-740582019-03-13T01:47:24Z Discovery of a radio galaxy at z = 5.72 Saxena, A. Marinello, M. Overzier, R. Best, P. Röttgering, H. Duncan, K. Prandoni, I. Pentericci, L. Magliocchetti, M. Paris, D. Cusano, F. Marchi, F. Intema, Hubertus Miley, G. We report the discovery of the most distant radio galaxy to date, TGSS J1530+1049 at a redshift of z = 5.72, close to the presumed end of the Epoch of Reionization. The radio galaxy was selected from the TGSS ADR1 survey at 150 MHz for having an ultra-steep spectral index, a1.4 GHz150 MHz = -1.4 and a compact morphology obtained using VLA imaging at 1.4 GHz. No optical or infrared counterparts for the radio source were found in publicly available sky surveys. Follow-up optical spectroscopy at the radio position using GMOS on Gemini North revealed the presence of a single emission line. We identify this line as Lyman alpha at z = 5.72, because of its asymmetric line profile, the absence of other optical/UV lines in the spectrum, and a high equivalent width. With an Lya luminosity of 5.7 × 1042 erg s-1 and an FWHM of 370 km s-1, TGSS J1530+1049 is comparable to 'non-radio' Lyman alpha emitters (LAEs) at a similar redshift. However, with a radio luminosity of log L150MHz = 29.1 W Hz-1 and a deconvolved physical size 3.5 kpc, its radio properties are similar to other known radio galaxies at z > 4. Subsequent J and K band imaging using LUCI on the Large Binocular Telescope resulted in non-detection of the host galaxy down to 3s limits of J > 24.4 and K > 22.4 (Vega). The K band limit is consistent withz > 5 from the K-z relation for radio galaxies and helps rule out low redshifts. The stellar mass limit derived using simple stellar population models is Mstars < 1010.5 M?. Its relatively low stellar mass and small radio and Lya sizes suggest that TGSS J1530+1049 may be a radio galaxy in an early phase of its evolution. 2018 Journal Article http://hdl.handle.net/20.500.11937/74058 10.1093/mnras/sty1996 Oxford University Press fulltext |
| spellingShingle | Saxena, A. Marinello, M. Overzier, R. Best, P. Röttgering, H. Duncan, K. Prandoni, I. Pentericci, L. Magliocchetti, M. Paris, D. Cusano, F. Marchi, F. Intema, Hubertus Miley, G. Discovery of a radio galaxy at z = 5.72 |
| title | Discovery of a radio galaxy at z = 5.72 |
| title_full | Discovery of a radio galaxy at z = 5.72 |
| title_fullStr | Discovery of a radio galaxy at z = 5.72 |
| title_full_unstemmed | Discovery of a radio galaxy at z = 5.72 |
| title_short | Discovery of a radio galaxy at z = 5.72 |
| title_sort | discovery of a radio galaxy at z = 5.72 |
| url | http://hdl.handle.net/20.500.11937/74058 |