Jet evolution, flux ratios and light-travel time effects
Studies of the knotty jets in both quasars and microquasars frequently make use of the ratio of the intensities of corresponding knots on opposite sides of the nucleus in order to infer the product of the intrinsic jet speed (beta) and the cosine of the inclination angle of the jet-axis (cos{theta})...
| Үндсэн зохиолчид: | , , |
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| Формат: | Journal article |
| Хэл сонгох: | English |
| Хэвлэсэн: |
Institute of Physics Publishing
2004
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| _version_ | 1826275933296787456 |
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| author | Miller-Jones, J Blundell, K Duffy, P |
| author_facet | Miller-Jones, J Blundell, K Duffy, P |
| author_sort | Miller-Jones, J |
| collection | OXFORD |
| description | Studies of the knotty jets in both quasars and microquasars frequently make use of the ratio of the intensities of corresponding knots on opposite sides of the nucleus in order to infer the product of the intrinsic jet speed (beta) and the cosine of the inclination angle of the jet-axis (cos{theta}), via the formalism I_{a}/I_{r} = ((1+beta cos{theta})/(1-beta cos{theta}))^{3+alpha}, where alpha relates the intensity I_{nu} as a function of frequency nu as I_{nu} propto nu^{-alpha}. Where beta cos{theta} is determined independently, the intensity ratio of a given pair of jet to counter-jet knots is over-predicted by the above formalism compared with the intensity ratio actually measured from radio images. As an example in the case of Cygnus X-3 the original formalism predicts an intensity ratio of about 185, whereas the observed intensity ratio at one single epoch is about 3. Mirabel and Rodriguez (1999) have refined the original formalism, and suggested measuring the intensity ratio of knots when they are at equal angular separations from the nucleus. This method is only applicable where there is sufficient time-sampling with sufficient physical resolution to interpolate the intensities of the knots at equal distances from the nucleus, and can therefore be difficult to apply to microquasars and is impossible to apply to quasars. Accounting for both the light-travel time between the knots and the simple evolution of the knots themselves reconciles this over-prediction and renders the original formalism obsolete. |
| first_indexed | 2024-03-06T23:06:21Z |
| format | Journal article |
| id | oxford-uuid:63f1c367-7a77-4d13-a897-386b7f4fba0c |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T23:06:21Z |
| publishDate | 2004 |
| publisher | Institute of Physics Publishing |
| record_format | dspace |
| spelling | oxford-uuid:63f1c367-7a77-4d13-a897-386b7f4fba0c2022-03-26T18:16:02ZJet evolution, flux ratios and light-travel time effectsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:63f1c367-7a77-4d13-a897-386b7f4fba0cEnglishSymplectic Elements at OxfordInstitute of Physics Publishing2004Miller-Jones, JBlundell, KDuffy, PStudies of the knotty jets in both quasars and microquasars frequently make use of the ratio of the intensities of corresponding knots on opposite sides of the nucleus in order to infer the product of the intrinsic jet speed (beta) and the cosine of the inclination angle of the jet-axis (cos{theta}), via the formalism I_{a}/I_{r} = ((1+beta cos{theta})/(1-beta cos{theta}))^{3+alpha}, where alpha relates the intensity I_{nu} as a function of frequency nu as I_{nu} propto nu^{-alpha}. Where beta cos{theta} is determined independently, the intensity ratio of a given pair of jet to counter-jet knots is over-predicted by the above formalism compared with the intensity ratio actually measured from radio images. As an example in the case of Cygnus X-3 the original formalism predicts an intensity ratio of about 185, whereas the observed intensity ratio at one single epoch is about 3. Mirabel and Rodriguez (1999) have refined the original formalism, and suggested measuring the intensity ratio of knots when they are at equal angular separations from the nucleus. This method is only applicable where there is sufficient time-sampling with sufficient physical resolution to interpolate the intensities of the knots at equal distances from the nucleus, and can therefore be difficult to apply to microquasars and is impossible to apply to quasars. Accounting for both the light-travel time between the knots and the simple evolution of the knots themselves reconciles this over-prediction and renders the original formalism obsolete. |
| spellingShingle | Miller-Jones, J Blundell, K Duffy, P Jet evolution, flux ratios and light-travel time effects |
| title | Jet evolution, flux ratios and light-travel time effects |
| title_full | Jet evolution, flux ratios and light-travel time effects |
| title_fullStr | Jet evolution, flux ratios and light-travel time effects |
| title_full_unstemmed | Jet evolution, flux ratios and light-travel time effects |
| title_short | Jet evolution, flux ratios and light-travel time effects |
| title_sort | jet evolution flux ratios and light travel time effects |
| work_keys_str_mv | AT millerjonesj jetevolutionfluxratiosandlighttraveltimeeffects AT blundellk jetevolutionfluxratiosandlighttraveltimeeffects AT duffyp jetevolutionfluxratiosandlighttraveltimeeffects |