ALMA detection of a disc-dominated [C II] emission line at z = 4.6 in the luminous QSO J1554+1937
We present observations and analysis of an unusual [C ii] emission line in the very luminous quasi-stellar object (QSO) SDSS J155426.16+193703.0 at z ~ 4.6. The line is extremely broad (full width at half-maximum 735 km s−1) and seems to have a flat-topped or double-peaked line profile. A velocity m...
| Main Authors: | , , , |
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| Format: | Journal Article |
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Oxford University Press
2015
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| Online Access: | http://hdl.handle.net/20.500.11937/19453 |
| _version_ | 1848750038185934848 |
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| author | Kimball, A. Lacy, M. Lonsdale, C. Macquart, Jean-Pierre |
| author_facet | Kimball, A. Lacy, M. Lonsdale, C. Macquart, Jean-Pierre |
| author_sort | Kimball, A. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We present observations and analysis of an unusual [C ii] emission line in the very luminous quasi-stellar object (QSO) SDSS J155426.16+193703.0 at z ~ 4.6. The line is extremely broad (full width at half-maximum 735 km s−1) and seems to have a flat-topped or double-peaked line profile. A velocity map of the line shows a gradient across the source that indicates large-scale rotation of star-forming gas. Together, the velocity map and line profile suggest the presence of a massive rotating disc with a dynamical mass Mdyn ≳5×1010 M☉. Using the assumption of a rotating disc origin, we employ an empirical relation between galaxy disc circular velocity and bulge velocity dispersion (σ) to estimate that σ > 310 km s−1, subject to a correction for the unknown disc inclination. This result implies that this source is consistent with the local M–σ relation, or offset at most by an order of magnitude in black hole mass. In contrast, the assumption of a bulge origin for the [C ii] emission line would lead to a conclusion that the black hole is nearly two orders of magnitude more massive than predicted by the M–σ relation, similar to previous findings for other high-redshift QSOs. As disc rotation may be a common origin for [C ii] emission at high redshifts, these results stress that careful consideration of dynamical origins is required when using observations of this line to derive properties of high-redshift galaxies. |
| first_indexed | 2025-11-14T07:30:28Z |
| format | Journal Article |
| id | curtin-20.500.11937-19453 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:30:28Z |
| publishDate | 2015 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-194532017-09-13T13:43:08Z ALMA detection of a disc-dominated [C II] emission line at z = 4.6 in the luminous QSO J1554+1937 Kimball, A. Lacy, M. Lonsdale, C. Macquart, Jean-Pierre We present observations and analysis of an unusual [C ii] emission line in the very luminous quasi-stellar object (QSO) SDSS J155426.16+193703.0 at z ~ 4.6. The line is extremely broad (full width at half-maximum 735 km s−1) and seems to have a flat-topped or double-peaked line profile. A velocity map of the line shows a gradient across the source that indicates large-scale rotation of star-forming gas. Together, the velocity map and line profile suggest the presence of a massive rotating disc with a dynamical mass Mdyn ≳5×1010 M☉. Using the assumption of a rotating disc origin, we employ an empirical relation between galaxy disc circular velocity and bulge velocity dispersion (σ) to estimate that σ > 310 km s−1, subject to a correction for the unknown disc inclination. This result implies that this source is consistent with the local M–σ relation, or offset at most by an order of magnitude in black hole mass. In contrast, the assumption of a bulge origin for the [C ii] emission line would lead to a conclusion that the black hole is nearly two orders of magnitude more massive than predicted by the M–σ relation, similar to previous findings for other high-redshift QSOs. As disc rotation may be a common origin for [C ii] emission at high redshifts, these results stress that careful consideration of dynamical origins is required when using observations of this line to derive properties of high-redshift galaxies. 2015 Journal Article http://hdl.handle.net/20.500.11937/19453 10.1093/mnras/stv1160 Oxford University Press fulltext |
| spellingShingle | Kimball, A. Lacy, M. Lonsdale, C. Macquart, Jean-Pierre ALMA detection of a disc-dominated [C II] emission line at z = 4.6 in the luminous QSO J1554+1937 |
| title | ALMA detection of a disc-dominated [C II] emission line at z = 4.6 in the luminous QSO J1554+1937 |
| title_full | ALMA detection of a disc-dominated [C II] emission line at z = 4.6 in the luminous QSO J1554+1937 |
| title_fullStr | ALMA detection of a disc-dominated [C II] emission line at z = 4.6 in the luminous QSO J1554+1937 |
| title_full_unstemmed | ALMA detection of a disc-dominated [C II] emission line at z = 4.6 in the luminous QSO J1554+1937 |
| title_short | ALMA detection of a disc-dominated [C II] emission line at z = 4.6 in the luminous QSO J1554+1937 |
| title_sort | alma detection of a disc-dominated [c ii] emission line at z = 4.6 in the luminous qso j1554+1937 |
| url | http://hdl.handle.net/20.500.11937/19453 |