Search

Your search keyword '"Starkey D"' showing total 13 results
Start Over Author "Starkey D" Journal monthly notices of the royal astronomical society
13 results on '"Starkey D"'

2. Rimmed and rippled accretion disc models to explain AGN continuum lags.

Author

Starkey, D A, (黄嘉沐), Jiamu Huang, Horne, Keith, and (林潮), Douglas N C Lin

Subjects
*ACCRETION disks, *ACTIVE galactic nuclei, *SPECTRAL energy distribution, *BLACK holes, *GRAVITATIONAL instability, *ALBEDO
Abstract

We propose a solution to the problem of accretion disc sizes in active galactic nuclei being larger when measured by reverberation mapping than predicted by theory. Considering the disc's exposed-surface thickness profile H (r), our solution invokes a steep rim or rippled structures irradiated by the central lamp-post. We model the continuum lags and the faint and bright disc spectral energy distribution (SED) in the best-studied case NGC 5548 (black hole mass |$M_\bullet =7\times 10^7\, \mathrm{M}_\odot$|⁠ , disc inclination i  = 45°). With the lamp-post off, the faint-disc SED fixes a low accretion rate |$\dot{M}\simeq 0.0014~\mathrm{M}_\odot \, {\rm yr}^{-1}$| and high prograde black hole spin a • ≃ 0.93, for which |$r_{\rm in}=2\, G\, M_\bullet /c^2$| and |$L_{\rm disc}=0.25\, \dot{M}\, c^2$|⁠. The bright-disc SED then requires a lamp-post luminosity |${L_{\rm LP}}\simeq 5\, \dot{M}\, c^2/(1-A)$| for disc albedo A. Reprocessing on the thin disc with T  ∝  r −3/4 gives time lags τ ∝ λ4/3 but three times smaller than observed. Introducing a steep H (r) rim, or multiple crests, near r ∼ 5 light days, reprocessing on the steep centre-facing slope increases temperatures from ∼1500 to ∼6000 K, and this increases optical lags to match the lag data. Most of the disc surface maintains the cooler T  ∝  r −3/4 profile that matches the SED. The bright lamp-post may be powered by magnetic links tapping the black hole spin. The steep rim occurs near the disc's dust sublimation radius as in the 'failed disc wind model for broad-line clouds'. Lens–Thirring torques aligning the disc and black hole spin may also raise a warp and associated waves. In both scenarios, the small density scale height implied by the inferred value of H (r) suggests possible marginal gravitational instability in the disc. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

3. Intensive disc-reverberation mapping of Fairall 9: first year of Swift and LCO monitoring

Author

Hernández Santisteban, J V, primary, Edelson, R, additional, Horne, K, additional, Gelbord, J M, additional, Barth, A J, additional, Cackett, E M, additional, Goad, M R, additional, Netzer, H, additional, Starkey, D, additional, Uttley, P, additional, Brandt, W N, additional, Korista, K, additional, Lohfink, A M, additional, Onken, C A, additional, Page, K L, additional, Siegel, M, additional, Vestergaard, M, additional, Bisogni, S, additional, Breeveld, A A, additional, Cenko, S B, additional, Dalla Bontà, E, additional, Evans, P A, additional, Ferland, G, additional, Gonzalez-Buitrago, D H, additional, Grupe, D, additional, Joner, M D, additional, Kriss, G, additional, LaPorte, S J, additional, Mathur, S, additional, Marshall, F, additional, Mehdipour, M, additional, Mudd, D, additional, Peterson, B M, additional, Schmidt, T, additional, Vaughan, S, additional, and Valenti, S, additional

Published
2020
Full Text
View/download PDF

4. The first spectroscopic dust reverberation programme on active galactic nuclei: the torus in NGC 5548

Author

Landt, H, primary, Ward, M J, additional, Kynoch, D, additional, Packham, C, additional, Ferland, G J, additional, Lawrence, A, additional, Pott, J-U, additional, Esser, J, additional, Horne, K, additional, Starkey, D A, additional, Malhotra, D, additional, Fausnaugh, M M, additional, Peterson, B M, additional, Wilman, R J, additional, Riffel, R A, additional, Storchi-Bergmann, T, additional, Barth, A J, additional, Villforth, C, additional, and Winkler, H, additional

Published
2019
Full Text
View/download PDF

6. OGLE-2014-BLG-1186: gravitational microlensing providing evidence for a planet orbiting the foreground star or for a close binary source?

Author

Dominik, M, primary, Bachelet, E, additional, Bozza, V, additional, Street, R A, additional, Han, C, additional, Hundertmark, M, additional, Udalski, A, additional, Bramich, D M, additional, Alsubai, K A, additional, Calchi Novati, S, additional, Ciceri, S, additional, D’Ago, G, additional, Figuera Jaimes, R, additional, Haugbølle, T, additional, Hinse, T C, additional, Horne, K, additional, Jørgensen, U G, additional, Juncher, D, additional, Kains, N, additional, Korhonen, H, additional, Mancini, L, additional, Menzies, J, additional, Popovas, A, additional, Rabus, M, additional, Rahvar, S, additional, Scarpetta, G, additional, Schmidt, R, additional, Skottfelt, J, additional, Snodgrass, C, additional, Southworth, J, additional, Starkey, D, additional, Steele, I A, additional, Surdej, J, additional, Tsapras, Y, additional, Wambsganss, J, additional, Wertz, O, additional, Pietrukowicz, P, additional, Szymański, M K, additional, Mróz, P, additional, Skowron, J, additional, Soszyński, I, additional, Ulaczyk, K, additional, Poleski, R, additional, Wyrzykowski, Ł, additional, and Kozłowski, S, additional

Published
2019
Full Text
View/download PDF

7. Orbital alignment and star-spot properties in the WASP-52 planetary system

Author

Mancini, L., primary, Southworth, J., additional, Raia, G., additional, Tregloan-Reed, J., additional, Mollière, P., additional, Bozza, V., additional, Bretton, M., additional, Bruni, I., additional, Ciceri, S., additional, D'Ago, G., additional, Dominik, M., additional, Hinse, T. C., additional, Hundertmark, M., additional, Jørgensen, U. G., additional, Korhonen, H., additional, Rabus, M., additional, Rahvar, S., additional, Starkey, D., additional, Calchi Novati, S., additional, Figuera Jaimes, R., additional, Henning, Th., additional, Juncher, D., additional, Haugbølle, T., additional, Kains, N., additional, Popovas, A., additional, Schmidt, R. W., additional, Skottfelt, J., additional, Snodgrass, C., additional, Surdej, J., additional, and Wertz, O., additional

Published
2016
Full Text
View/download PDF

8. High-precision photometry by telescope defocussing – VIII. WASP-22, WASP-41, WASP-42 and WASP-55

Author

Southworth, John, primary, Tregloan-Reed, J., additional, Andersen, M. I., additional, Calchi Novati, S., additional, Ciceri, S., additional, Colque, J. P., additional, D'Ago, G., additional, Dominik, M., additional, Evans, D. F., additional, Gu, S.-H., additional, Herrera-Cordova, A., additional, Hinse, T. C., additional, Jørgensen, U. G., additional, Juncher, D., additional, Kuffmeier, M., additional, Mancini, L., additional, Peixinho, N., additional, Popovas, A., additional, Rabus, M., additional, Skottfelt, J., additional, Tronsgaard, R., additional, Unda-Sanzana, E., additional, Wang, X.-B., additional, Wertz, O., additional, Alsubai, K. A., additional, Andersen, J. M., additional, Bozza, V., additional, Bramich, D. M., additional, Burgdorf, M., additional, Damerdji, Y., additional, Diehl, C., additional, Elyiv, A., additional, Figuera Jaimes, R., additional, Haugbølle, T., additional, Hundertmark, M., additional, Kains, N., additional, Kerins, E., additional, Korhonen, H., additional, Liebig, C., additional, Mathiasen, M., additional, Penny, M. T., additional, Rahvar, S., additional, Scarpetta, G., additional, Schmidt, R. W., additional, Snodgrass, C., additional, Starkey, D., additional, Surdej, J., additional, Vilela, C., additional, Essen, C. von, additional, and Wang, Y., additional

Published
2016
Full Text
View/download PDF

9. Accretion-disc precession in UX Ursae Majoris

Author

de Miguel, E., primary, Patterson, J., additional, Cejudo, D., additional, Ulowetz, J., additional, Jones, J. L., additional, Boardman, J., additional, Barret, D., additional, Koff, R., additional, Stein, W., additional, Campbell, T., additional, Vanmunster, T., additional, Menzies,  K., additional, Slauson, D., additional, Goff, W., additional, Roberts,  G., additional, Morelle, E., additional, Dvorak, S., additional, Hambsch, F.-J., additional, Starkey, D., additional, Collins, D., additional, Costello, M., additional, Cook, M. J., additional, Oksanen, A., additional, Lemay, D., additional, Cook, L. M., additional, Ogmen, Y., additional, Richmond, M., additional, and Kemp, J., additional

Published
2016
Full Text
View/download PDF

11. Larger and faster: revised properties and a shorter orbital period for the WASP-57 planetary system from a pro-am collaboration

Author

Southworth, John, primary, Mancini, L., additional, Tregloan-Reed, J., additional, Calchi Novati, S., additional, Ciceri, S., additional, D'Ago, G., additional, Delrez, L., additional, Dominik, M., additional, Evans, D. F., additional, Gillon, M., additional, Jehin, E., additional, Jørgensen, U. G., additional, Haugbølle, T., additional, Lendl, M., additional, Arena, C., additional, Barbieri, L., additional, Barbieri, M., additional, Corfini, G., additional, Lopresti, C., additional, Marchini, A., additional, Marino, G., additional, Alsubai, K. A., additional, Bozza, V., additional, Bramich, D. M., additional, Jaimes, R. Figuera, additional, Hinse, T. C., additional, Henning, Th., additional, Hundertmark, M., additional, Juncher, D., additional, Korhonen, H., additional, Popovas, A., additional, Rabus, M., additional, Rahvar, S., additional, Schmidt, R. W., additional, Skottfelt, J., additional, Snodgrass, C., additional, Starkey, D., additional, Surdej, J., additional, and Wertz, O., additional

Published
2015
Full Text
View/download PDF

12. High-precision photometry by telescope defocusing – VII. The ultrashort period planet WASP-103★

Author

Southworth, John, primary, Mancini, L., additional, Ciceri, S., additional, Budaj, J., additional, Dominik, M., additional, Figuera Jaimes, R., additional, Haugbølle, T., additional, Jørgensen, U. G., additional, Popovas, A., additional, Rabus, M., additional, Rahvar, S., additional, von Essen, C., additional, Schmidt, R. W., additional, Wertz, O., additional, Alsubai, K. A., additional, Bozza, V., additional, Bramich, D. M., additional, Calchi Novati, S., additional, D'Ago, G., additional, Hinse, T. C., additional, Henning, Th., additional, Hundertmark, M., additional, Juncher, D., additional, Korhonen, H., additional, Skottfelt, J., additional, Snodgrass, C., additional, Starkey, D., additional, and Surdej, J., additional

Published
2014
Full Text
View/download PDF

13. Accretion disc time lag distributions: applying CREAM to simulated AGN light curves.

Author

Starkey, D. A., Horne, Keith, and Villforth, C.

Subjects
*ACCRETION disks, *ASTRONOMICAL photometry, *ACTIVE galactic nuclei, *LIGHT curves, *ULTRAVIOLET radiation, *SUPERMASSIVE black holes
Abstract

Active galactic nuclei (AGN) vary in their brightness across all wavelengths. Moreover, longer wavelength ultraviolet-optical continuum light curves appear to be delayed with respect to shorter wavelength light curves. A simple way to model these delays is by assuming thermal reprocessing of a variable point source (a lamp post) by a blackbody accretion disc. We introduce a new method, CREAM (Continuum REprocessed AGN Markov Chain Monte Carlo), that models continuum variations using this lamp post model. The disc light curves lag the lamp post emission with a time delay distribution sensitive to the disc temperature-radius profile and inclination. We test CREAM's ability to recover both inclination and product of black hole mass and accretion rate MM?MM?, and show that the code is also able to infer the shape of the driving light curve. CREAM is applied to synthetic light curves expected from 1000 s exposures of a 17th magnitude AGN with a 2-m telescope in Sloan g and i bands with Signal-to-Noise Ratio (SNR) of 500-900 depending on the filter and lunar phase. We also test cream on poorer quality g and i light curves with SNR = 100. We find in the high-SNR case that cream can recover the accretion disc inclination to within an uncertainty of 5~ and an MM to within 0.04 dex. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results