The Subparsec-scale Structure and Evolution of Centaurus A. III. A Multi-epoch Spectral and Polarimetric VLBA Study
The Centaurus A radio galaxy, due to its proximity, presents itself as one of the few systems that allow the study of relativistic jet outflows at subparsec distances from the central supermassive black holes, with high signal to noise. We present the results from the first multi-epoch spectropolari...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2024-01-01
|
| Series: | The Astronomical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-3881/ad91a5 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1846118854359515136 |
|---|---|
| author | S. Prabu S. J. Tingay A. Bahramian J. C. A. Miller-Jones C. M. Wood S. P. O’Sullivan |
| author_facet | S. Prabu S. J. Tingay A. Bahramian J. C. A. Miller-Jones C. M. Wood S. P. O’Sullivan |
| author_sort | S. Prabu |
| collection | DOAJ |
| description | The Centaurus A radio galaxy, due to its proximity, presents itself as one of the few systems that allow the study of relativistic jet outflows at subparsec distances from the central supermassive black holes, with high signal to noise. We present the results from the first multi-epoch spectropolarimetric observations of Centaurus A at milliarcsecond resolution, with a continuous frequency coverage of 4.59−7.78 GHz. Using a Bayesian framework, we perform a comprehensive study of the jet kinematics, and discuss aspects of the jet geometry, including the jet inclination angle, jet opening angle, and the jet expansion profile. We calculate an upper limit on the jet’s inclination to the line of sight to be <25°, implying the lower limit on the intrinsic jet speed to be 0.2 c . On the observed very long baseline array scales, we detect new jet components launched by the central engine since our previous study. Using the observed frequency-dependent core shift in Centaurus A, we find the jet to have reached constant bulk speed and conical outflow at the regions probed by the base of the jet at 7.78−4.59 GHz, and we also estimate the location of the central black hole further upstream. Through polarimetric analysis (by applying rotation measure synthesis for the first time on very long baseline interferometry data), we find evidence to suggest the possible onset of acceleration toward the leading edge of Centaurus A’s subparsec-scale jet studied here. |
| format | Article |
| id | doaj-art-f796d8c2c95a40288660561cc5dba8c1 |
| institution | Kabale University |
| issn | 1538-3881 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj-art-f796d8c2c95a40288660561cc5dba8c12024-12-17T09:29:17ZengIOP PublishingThe Astronomical Journal1538-38812024-01-0116913710.3847/1538-3881/ad91a5The Subparsec-scale Structure and Evolution of Centaurus A. III. A Multi-epoch Spectral and Polarimetric VLBA StudyS. Prabu0https://orcid.org/0000-0003-3165-6785S. J. Tingay1https://orcid.org/0000-0002-8195-7562A. Bahramian2https://orcid.org/0000-0003-2506-6041J. C. A. Miller-Jones3https://orcid.org/0000-0003-3124-2814C. M. Wood4https://orcid.org/0000-0002-2758-0864S. P. O’Sullivan5https://orcid.org/0000-0002-3968-3051International Centre for Radio Astronomy Research, Curtin University , Bentley, WA 6102, AustraliaInternational Centre for Radio Astronomy Research, Curtin University , Bentley, WA 6102, AustraliaInternational Centre for Radio Astronomy Research, Curtin University , Bentley, WA 6102, AustraliaInternational Centre for Radio Astronomy Research, Curtin University , Bentley, WA 6102, AustraliaInternational Centre for Radio Astronomy Research, Curtin University , Bentley, WA 6102, AustraliaDepartamento de Física de la Tierra y Astrofísica, Instituto de Física de Partículas y del Cosmos , IPARCOS, SpainThe Centaurus A radio galaxy, due to its proximity, presents itself as one of the few systems that allow the study of relativistic jet outflows at subparsec distances from the central supermassive black holes, with high signal to noise. We present the results from the first multi-epoch spectropolarimetric observations of Centaurus A at milliarcsecond resolution, with a continuous frequency coverage of 4.59−7.78 GHz. Using a Bayesian framework, we perform a comprehensive study of the jet kinematics, and discuss aspects of the jet geometry, including the jet inclination angle, jet opening angle, and the jet expansion profile. We calculate an upper limit on the jet’s inclination to the line of sight to be <25°, implying the lower limit on the intrinsic jet speed to be 0.2 c . On the observed very long baseline array scales, we detect new jet components launched by the central engine since our previous study. Using the observed frequency-dependent core shift in Centaurus A, we find the jet to have reached constant bulk speed and conical outflow at the regions probed by the base of the jet at 7.78−4.59 GHz, and we also estimate the location of the central black hole further upstream. Through polarimetric analysis (by applying rotation measure synthesis for the first time on very long baseline interferometry data), we find evidence to suggest the possible onset of acceleration toward the leading edge of Centaurus A’s subparsec-scale jet studied here.https://doi.org/10.3847/1538-3881/ad91a5Active galactic nucleiInterferometersVery long baseline interferometryRelativistic jets |
| spellingShingle | S. Prabu S. J. Tingay A. Bahramian J. C. A. Miller-Jones C. M. Wood S. P. O’Sullivan The Subparsec-scale Structure and Evolution of Centaurus A. III. A Multi-epoch Spectral and Polarimetric VLBA Study The Astronomical Journal Active galactic nuclei Interferometers Very long baseline interferometry Relativistic jets |
| title | The Subparsec-scale Structure and Evolution of Centaurus A. III. A Multi-epoch Spectral and Polarimetric VLBA Study |
| title_full | The Subparsec-scale Structure and Evolution of Centaurus A. III. A Multi-epoch Spectral and Polarimetric VLBA Study |
| title_fullStr | The Subparsec-scale Structure and Evolution of Centaurus A. III. A Multi-epoch Spectral and Polarimetric VLBA Study |
| title_full_unstemmed | The Subparsec-scale Structure and Evolution of Centaurus A. III. A Multi-epoch Spectral and Polarimetric VLBA Study |
| title_short | The Subparsec-scale Structure and Evolution of Centaurus A. III. A Multi-epoch Spectral and Polarimetric VLBA Study |
| title_sort | subparsec scale structure and evolution of centaurus a iii a multi epoch spectral and polarimetric vlba study |
| topic | Active galactic nuclei Interferometers Very long baseline interferometry Relativistic jets |
| url | https://doi.org/10.3847/1538-3881/ad91a5 |
| work_keys_str_mv | AT sprabu thesubparsecscalestructureandevolutionofcentaurusaiiiamultiepochspectralandpolarimetricvlbastudy AT sjtingay thesubparsecscalestructureandevolutionofcentaurusaiiiamultiepochspectralandpolarimetricvlbastudy AT abahramian thesubparsecscalestructureandevolutionofcentaurusaiiiamultiepochspectralandpolarimetricvlbastudy AT jcamillerjones thesubparsecscalestructureandevolutionofcentaurusaiiiamultiepochspectralandpolarimetricvlbastudy AT cmwood thesubparsecscalestructureandevolutionofcentaurusaiiiamultiepochspectralandpolarimetricvlbastudy AT sposullivan thesubparsecscalestructureandevolutionofcentaurusaiiiamultiepochspectralandpolarimetricvlbastudy AT sprabu subparsecscalestructureandevolutionofcentaurusaiiiamultiepochspectralandpolarimetricvlbastudy AT sjtingay subparsecscalestructureandevolutionofcentaurusaiiiamultiepochspectralandpolarimetricvlbastudy AT abahramian subparsecscalestructureandevolutionofcentaurusaiiiamultiepochspectralandpolarimetricvlbastudy AT jcamillerjones subparsecscalestructureandevolutionofcentaurusaiiiamultiepochspectralandpolarimetricvlbastudy AT cmwood subparsecscalestructureandevolutionofcentaurusaiiiamultiepochspectralandpolarimetricvlbastudy AT sposullivan subparsecscalestructureandevolutionofcentaurusaiiiamultiepochspectralandpolarimetricvlbastudy |