Abstract
The high-ionization lines of the broad-line region (BLR) of thermal active galactic nuclei (AGNs) show blueshifts of a few hundred km/s to several thousand km/sec with respect to the low-ionization lines. This has long been thought to be due to the high-ionization lines of the BLR arising in a wind of which the far side of the outflow is blocked from our view by the accretion disc. Evidence for and against the disc-wind model is discussed. The biggest problem for the model is that velocity-resolved reverberation mapping repeatedly fails to show the expected kinematic signature of outflow of the BLR. The disc-wind model also cannot readily reproduce the red side of the line profiles of high-ionization lines. The rapidly falling density in an outflow makes it difficult to obtain high equivalent widths. We point out a number of major problems with associating the BLR with the outflows producing broad absorption lines. An explanation which avoids all these problems and satisfies the constraints of both the line profiles and velocity-resolved reverberation-mapping is a model in which the blueshifting is due to scattering off material spiraling inwards with an inflow velocity of half the velocity of the blueshifting. We discuss how recent reverberation mapping results are consistent with the scattering-plus-inflow model but do not support a disc-wind model. We propose that the anti-correlation of the apparent redshifting of H\(\beta\) with the blueshifting of C iv is a consequence of contamination of the red wings of H\(\beta\) by the broad wings of [O iii].
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Notes
Thermal AGNs are high accretion rate AGNs where the energy output is dominated by thermal emission of the accretion disc. Non-thermal AGNs, which we do not consider here, are very low accretion rate AGNs where the energy output is dominated by the mechanical energy of the radio jet. See Antonucci (2012) for detailed discussion.
It is important to recognize that viscosity alone in an accretion disc, while important for energy generation, does not allow the accretion of material from infinity onto a black hole—see Fig. 1 of Pringle (1981).
The flux at a given frequency comes mostly from the part of a disc at the temperature given by the Stefan-Boltzmann law. The monochromatic luminosity gives the area at around that temperature and hence the size of the disk. Observationally the size of the disc can be determined from multi-wavelength reverberation mapping (Collier et al. 1998; Wanders et al. 1997). It can also be inferred less directly from gravitational microlensing (Mortonson et al. 2005).
It should be noted that the SDSS BALQSO catalogue of Trump et al. (2006) is cut off at a maximum outflow velocity of −29,000. This corresponds to the velocity at which C iv absorption can overlap with lower-velocity Si iv absorption. It is not a real cutoff in the distribution of outflow velocities.
References
Allen, J.T., Hewett, P.C., Maddox, N., Richards, G.T., Belokurov, V.: Mon. Not. R. Astron. Soc. 410, 860 (2011)
Antonucci, R.R.J.: Astron. Astrophys. Trans. 27, 557 (2012)
Auer, L.H., van Blerkom, D.: Astrophys. J. 178, 175 (1972)
Baldwin, J.A., McMahon, R., Hazard, C., Williams, R.E.: Astrophys. J. 327, 103 (1988)
Bentz, M.C., Walsh, J.L., Barth, A.J., et al.: Astrophys. J. Lett. 689, L21–L24 (2008)
Blandford, R.D., Payne, D.G.: Mon. Not. R. Astron. Soc. 199, 883 (1982)
Blumenthal, G.R., Mathews, W.G.: Astrophys. J. 198, 517 (1975)
Boroson, T.A., Green, R.F.: Astrophys. J. Suppl. Ser. 80, 109 (1992)
Brotherton, M.S., Wills, B.J., Francis, P.J., Steidel, C.C.: Astrophys. J. 430, 495 (1994)
Capellupo, D.M., Hamann, F., Shields, J.C., Halpern, J.P., Barlow, T.A.: Mon. Not. R. Astron. Soc. 429, 1872 (2013)
Clavel, J., et al.: Astrophys. J. 366, 64 (1991)
Collier, S.J., Horne, K., Kaspi, S., et al.: Astrophys. J. 500, 162 (1998)
Collin-Souffrin, S., Lasota, J.-P.: Publ. Astron. Soc. Pac. 100, 1041 (1988)
Collin-Souffrin, S., Dyson, J.E., McDowell, J.C., Perry, J.J.: Mon. Not. R. Astron. Soc. 232, 539 (1988)
Corbin, M.R.: Astrophys. J. 357, 346 (1990)
Corbin, M.R.: Astrophys. J. 391, 577 (1992)
Crenshaw, D.M., Blackwell, J.H. Jr.: Astrophys. J. Lett. 358, L37 (1990)
Crenshaw, D.M., Schmitt, H.R., Kraemer, S.B., Mushotzky, R.F., Dunn, J.P.: Astrophys. J. 708, 419 (2010)
De Rosa, G., Peterson, B.M., Ely, J., et al.: Astrophys. J. 806, 128 (2015)
Denney, K.D., et al.: Astrophys. J. Lett. 704, L80 (2009)
Done, C., Krolik, J.H.: Astrophys. J. 463, 144 (1996)
Doroshenko, V.T., Sergeev, S.G., Pronik, V.I., Chuvaev, K.K.: Astron. Lett. 25, 569 (1999)
Elvis, M.: Astrophys. J. 545, 63 (2000)
Ferrara, A., Pietrini, P.: Astrophys. J. 405, 130 (1993)
Foltz, C.B., Wilkes, B.J., Peterson, B.M.: Astron. J. 88, 1702 (1983)
Francis, P.J., Hewett, P.C., Foltz, C.B., Chaffee, F.H.: Astrophys. J. 398, 476 (1992)
Gaskell, C.M.: Astrophys. J. 263, 79 (1982)
Gaskell, C.M.: Astrophys. J. Lett. 267, L1 (1983)
Gaskell, C.M.: NATO ASI Ser., Ser. C 208, 29 (1987)
Gaskell, C.M.: Astrophys. J. 325, 114 (1988)
Gaskell, C.M.: New Astron. Rev. 53, 140 (2009)
Gaskell, C.M.: Astrophys. J. (2010, submitted). arXiv:1008.1057
Gaskell, C.M.: Balt. Astron. 20, 392 (2011)
Gaskell, C.M., Goosmann, R.W.: Astrophys. J. 769, 30 (2013)
Gaskell, C.M., Mexicana, R.: Rev. Mex. Astron. Astrofís., Ser. Conf. 32, 1 (2008)
Gaskell, C.M., Snedden, S.A.: Bull. Am. Astron. Soc. 29, 1252 (1997)
Gaskell, C.M., Sparke, L.S.: Astrophys. J. 305, 175 (1986)
Gaskell, C.M., Klimek, E.S., Nazarova, L.S.: Astrophys. J. (2007, submitted). arXiv:0711.1025
Goosmann, R.W., Gaskell, C.M.: Astron. Astrophys. 465, 129 (2007)
Grier, C.J., Peterson, B.M., Horne, K., et al.: Astrophys. J. 764, 47 (2013)
Grier, C.J., Hall, P.B., Brandt, W.N., Trump, J.R., et al.: Astrophys. J. 806, 111 (2015)
Hall, P.B., Brandt, W.N., Petitjean, P., et al.: Mon. Not. R. Astron. Soc. 434, 222 (2013)
Heckman, T.M., Miley, G.K., van Breugel, W.J.M., Butcher, H.R.: Astrophys. J. 247, 403 (1981)
Hu, C., Wang, J.-M., Ho, L.C., et al.: Astrophys. J. 687, 78 (2008)
Jackson, N., Browne, I.W.A.: Mon. Not. R. Astron. Soc. 236, 97 (1989)
Jannuzi, B.T., Hartig, G.F., Kirhakos, S., Sargent, W.L.W., Turnshek, D.A., Weymann, R.J., Bahcall, J.N., Bergeron, J., Boksenberg, A., Savage, B.D., Schneider, D.P., Wolfe, A.M.: Astrophys. J. Lett. 470, L11 (1996)
Joly, M.: Astron. Astrophys. 192, 87 (1988)
Kallman, T.R., Krolik, J.H.: Astrophys. J. 308, 805 (1986)
Kaneko, N., Ohtani, H.: Astron. J. 73, 899 (1968)
Kollatschny, W.: Astron. Astrophys. 407, 461 (2003)
Kollatschny, W., Dietrich, M.: Astron. Astrophys. 314, 43 (1996)
Kollatschny, W., Zetzl, M.: Astron. Astrophys. 558, A26 (2013)
Kollatschny, W., Bischoff, K., Robinson, E.L., Welsh, W.F., Hill, G.J.: Astron. Astrophys. 379, 125 (2001)
Koratkar, A.P., Gaskell, C.M.: Astrophys. J. 345, 637 (1989)
Koratkar, A.P., Gaskell, C.M.: Astrophys. J. Suppl. Ser. 75, 719 (1991)
Korista, K.T., Ferland, G.J.: Astrophys. J. 495, 672 (1998)
Korista, K.T., et al.: Astrophys. J. Suppl. Ser. 97, 285 (1995)
Krolik, J.H., Horne, K., Kallman, T.R., Malkan, M.A., Edelson, R.A., Kriss, G.A., et al.: Astrophys. J. 371, 541 (1991)
Lee, L.W., Turnshek, D.A.: Astrophys. J. Lett. 453, L61 (1995)
Leighly, K.M., Moore, J.R.: Astrophys. J. 611, 107 (2004)
Marin, F., Goosmann, R.W., Gaskell, C.M., Porquet, D., Dovčiak, M.: Astron. Astrophys. 548, A121 (2012)
Marin, F., Goosmann, R.W., Gaskell, C.M.: Astron. Astrophys. 577, A66 (2015)
Mathews, W.G.: Astrophys. J. 412, L17 (1993)
Mathis, J.S.: Astrophys. J. 162, 761 (1970)
Meyers, K.A., Peterson, B.M.: Publ. Astron. Soc. Pac. 97, 734 (1985)
Mortonson, M.J., Schechter, P.L., Wambsganss, J.: Astrophys. J. 628, 594 (2005)
Osterbrock, D.E., Shuder, J.M.: Astrophys. J. Suppl. Ser. 49, 149 (1982)
Pancoast, A., Brewer, B.J., Treu, T., et al.: Mon. Not. R. Astron. Soc. 445, 3073 (2014)
Peterson, B.M.: Advanced Lectures on the Starburst-AGN connection p. 3. World Scientific, Singapore (2001)
Peterson, B.M., Wandel, A.: Astrophys. J. Lett. 540, L13 (2000)
Phillips, M.M.: Astrophys. J. Suppl. Ser. 38, 187 (1978a)
Phillips, M.M.: Astrophys. J. 226, 736 (1978b)
Pringle, J.E.: Annu. Rev. Astron. Astrophys. 19, 137 (1981)
Richards, G.T., Vanden Berk, D.E., Reichard, T.A., Hall, P.B., Schneider, D.P., SubbaRao, M., Thakar, A.R., York, D.G.: Astron. J. 124, 1 (2002)
Risaliti, G., Elvis, M.: Astron. Astrophys. 516, A89 (2010)
Rodríguez Hidalgo, P., Hamann, F., Hall, P.: Mon. Not. R. Astron. Soc. 411, 247 (2011)
Rogerson, J.A., Hall, P.B., Rodríguez Hidalgo, P., Pirkola, P., Brandt, Mon, W.N.: Not. R. Astron. Soc. (2016, in press)
Saturni, F.G., Trevese, D., Vagnetti, F., Perna, M., Dadina, M.: Astron. Astrophys. (2016, in press). arXiv:1512.03195
Sergeev, S.G., Pronik, V.I., Sergeeva, E.A., Malkov, Y.F.: Astrophys. J. Suppl. Ser. 121, 159 (1999)
Steidel, C.C., Sargent, W.L.W.: Astrophys. J. 382, 433 (1991)
Stirpe, G.M., van Groningen, E., de Bruyn, A.G.: Astron. Astrophys. 211, 310 (1989)
Suganuma, M., Yoshii, Y., Kobayashi, Y., et al.: Astrophys. J. 639, 46 (2006)
Sulentic, J.W., Marziani, P., Dultzin-Hacyan, D., Calvani, M., Moles, M.: Astrophys. J. Lett. 445, L85 (1995)
Sulentic, J.W., Zwitter, T., Marziani, P., Dultzin-Hacyan, D.: Astrophys. J. Lett. 536, L5 (2000)
Sulentic, J.W., Marziani, P., Zamfir, S., Meadows, Z.A.: Astrophys. J. Lett. 752, L7 (2012)
Trump, J.R., Hall, P.B., Reichard, T.A., Richards, G.T., Schneider, D.P., Vanden Berk, D.E., Knapp, G.R., Anderson, S.F., Fan, X.-H., Brinkman, J., Kleinman, S.J., Atsuko, N.: Astrophys. J. Suppl. Ser. 165, 1 (2006)
Tytler, D., Fan, X.-M.: Astrophys. J. Suppl. Ser. 79, 1 (1992)
Ulrich, M.-H., Horne, K.: Mon. Not. R. Astron. Soc. 283, 748 (1996)
Véron, P., Gonçalves, A.C., Véron-Cetty, M.-P.: Astron. Astrophys. 384, 826 (2002)
Wanders, I., Peterson, B.M., Alloin, D., et al.: Astrophys. J. Suppl. Ser. 113, 69 (1997)
Weymann, R.J.: Astrophys. J. 160, 31 (1970)
Weymann, R.J., Carswell, R.F., Smith, M.G.: Annu. Rev. Astron. Astrophys. 19, 41 (2016)
Wilkes, B.J.: Mon. Not. R. Astron. Soc. 207, 73 (1984)
Wills, B.J., Brotherton, M.S., Fang, D., Steidel, C.C., Sargent, W.L.W.: Astrophys. J. 415, 563 (1993)
Wu, J., Brandt, W.N., Anderson, S.F., et al.: Astrophys. J. 747, 10 (2012)
Zamanov, R., Marziani, P., Sulentic, J.W., Calvani, M., Dultzin-Hacyan, D., Bachev, R.: Astrophys. J. 576, L9 (2002)
Zhang, K., Dong, X.-B., Wang, T.-G., Gaskell, C.M.: Astrophys. J. 737, 71 (2011)
Acknowledgements
We are grateful to Jack Sulentic, Paola Marziani, and Ski Antonucci for useful discussion and to Todd Boroson, Richard Green, Kate Grier, Wolfram Kollatschny, and Julian Krolik for permission to use figures from their papers. We would also like to express our appreciation to the anonymous referee for a detailed and helpful report. RWG acknowledges support from French grant ANR-11-JS56-013-01.
Author information
Authors and Affiliations
Corresponding author
Additional information
This article belongs to the Topical Collection: Line Shifts in Astrophysics and Laboratory Plasma. Guest Editors: Jack Sulentic, Luka C. Popovic.
Rights and permissions
About this article
Cite this article
Gaskell, C.M., Goosmann, R.W. The case for inflow of the broad-line region of active galactic nuclei. Astrophys Space Sci 361, 67 (2016). https://doi.org/10.1007/s10509-015-2648-1
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s10509-015-2648-1