Ultraluminous star-forming galaxies and extremely luminous warm molecular hydrogen emission at z = 2.16 in the PKS1138-26 radio galaxy protocluster
A deep Spitzer Infrared Spectrograph map of the PKS 1138–26 galaxy protocluster reveals ultraluminous polycyclic aromatic hydrocarbon (PAH) emission from obscured star formation in three protocluster galaxies, including Hα-emitter (HAE) 229, HAE 131, and the central Spiderweb Galaxy. Star formation...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
| Published: |
2012
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| Online Access: | http://hdl.handle.net/20.500.11937/37555 |
| _version_ | 1848755081300672512 |
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| author | Ogle, P. Davies, J. Appleton, P. Bertincourt, B. Seymour, Nick Helou, G. |
| author_facet | Ogle, P. Davies, J. Appleton, P. Bertincourt, B. Seymour, Nick Helou, G. |
| author_sort | Ogle, P. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | A deep Spitzer Infrared Spectrograph map of the PKS 1138–26 galaxy protocluster reveals ultraluminous polycyclic aromatic hydrocarbon (PAH) emission from obscured star formation in three protocluster galaxies, including Hα-emitter (HAE) 229, HAE 131, and the central Spiderweb Galaxy. Star formation rates of ~500-1100 M ☉ yr–1 are estimated from the 7.7 μm PAH feature. At such prodigious formation rates, the galaxy stellar masses will double in 0.6-1.1 Gyr. We are viewing the peak epoch of star formation for these protocluster galaxies. However, it appears that extinction of Hα is much greater (up to a factor of 40) in the two ULIRG HAEs compared to the Spiderweb. This may be attributed to different spatial distributions of star formation-nuclear star formation in the HAEs versus extended star formation in accreting satellite galaxies in the Spiderweb. We find extremely luminous mid-IR rotational line emission from warm molecular hydrogen in the Spiderweb Galaxy, with L(H2 0-0 S(3)) = 1.4 × 1044 erg s–1 (3.7 × 1010 L ☉), ~20 times more luminous than any previously known H2 emission galaxy (MOHEG). Depending on the temperature, this corresponds to a very large mass of >9 × 106-2 × 109 M ☉ of T > 300 K molecular gas, which may be heated by the PKS 1138–26 radio jet, acting to quench nuclear star formation. There is >8 times more warm H2 at these temperatures in the Spiderweb than what has been seen in low-redshift (z < 0.2) radio galaxies, indicating that the Spiderweb may have a larger reservoir of molecular gas than more evolved radio galaxies. This is the highest redshift galaxy yet in which warm molecular hydrogen has been directly detected. |
| first_indexed | 2025-11-14T08:50:38Z |
| format | Journal Article |
| id | curtin-20.500.11937-37555 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:50:38Z |
| publishDate | 2012 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-375552018-03-29T09:07:22Z Ultraluminous star-forming galaxies and extremely luminous warm molecular hydrogen emission at z = 2.16 in the PKS1138-26 radio galaxy protocluster Ogle, P. Davies, J. Appleton, P. Bertincourt, B. Seymour, Nick Helou, G. A deep Spitzer Infrared Spectrograph map of the PKS 1138–26 galaxy protocluster reveals ultraluminous polycyclic aromatic hydrocarbon (PAH) emission from obscured star formation in three protocluster galaxies, including Hα-emitter (HAE) 229, HAE 131, and the central Spiderweb Galaxy. Star formation rates of ~500-1100 M ☉ yr–1 are estimated from the 7.7 μm PAH feature. At such prodigious formation rates, the galaxy stellar masses will double in 0.6-1.1 Gyr. We are viewing the peak epoch of star formation for these protocluster galaxies. However, it appears that extinction of Hα is much greater (up to a factor of 40) in the two ULIRG HAEs compared to the Spiderweb. This may be attributed to different spatial distributions of star formation-nuclear star formation in the HAEs versus extended star formation in accreting satellite galaxies in the Spiderweb. We find extremely luminous mid-IR rotational line emission from warm molecular hydrogen in the Spiderweb Galaxy, with L(H2 0-0 S(3)) = 1.4 × 1044 erg s–1 (3.7 × 1010 L ☉), ~20 times more luminous than any previously known H2 emission galaxy (MOHEG). Depending on the temperature, this corresponds to a very large mass of >9 × 106-2 × 109 M ☉ of T > 300 K molecular gas, which may be heated by the PKS 1138–26 radio jet, acting to quench nuclear star formation. There is >8 times more warm H2 at these temperatures in the Spiderweb than what has been seen in low-redshift (z < 0.2) radio galaxies, indicating that the Spiderweb may have a larger reservoir of molecular gas than more evolved radio galaxies. This is the highest redshift galaxy yet in which warm molecular hydrogen has been directly detected. 2012 Journal Article http://hdl.handle.net/20.500.11937/37555 10.1088/0004-637X/751/1/13 restricted |
| spellingShingle | Ogle, P. Davies, J. Appleton, P. Bertincourt, B. Seymour, Nick Helou, G. Ultraluminous star-forming galaxies and extremely luminous warm molecular hydrogen emission at z = 2.16 in the PKS1138-26 radio galaxy protocluster |
| title | Ultraluminous star-forming galaxies and extremely luminous warm molecular hydrogen emission at z = 2.16 in the PKS1138-26 radio galaxy protocluster |
| title_full | Ultraluminous star-forming galaxies and extremely luminous warm molecular hydrogen emission at z = 2.16 in the PKS1138-26 radio galaxy protocluster |
| title_fullStr | Ultraluminous star-forming galaxies and extremely luminous warm molecular hydrogen emission at z = 2.16 in the PKS1138-26 radio galaxy protocluster |
| title_full_unstemmed | Ultraluminous star-forming galaxies and extremely luminous warm molecular hydrogen emission at z = 2.16 in the PKS1138-26 radio galaxy protocluster |
| title_short | Ultraluminous star-forming galaxies and extremely luminous warm molecular hydrogen emission at z = 2.16 in the PKS1138-26 radio galaxy protocluster |
| title_sort | ultraluminous star-forming galaxies and extremely luminous warm molecular hydrogen emission at z = 2.16 in the pks1138-26 radio galaxy protocluster |
| url | http://hdl.handle.net/20.500.11937/37555 |