Suzaku observations of luminous quasars: Revealing the nature of high-energy blazar emission in low-level activity states

A. A. Abdo; M. Ackermann; M. Ajello; E. Antolini; L. Baldini; J. Ballet; G. Barbiellini; M. G. Baring; D. Bastieri; K. Bechtol; R. Bellazzini; B. Berenji; R. D. Blandford; E. D. Bloom; E. Bonamente; A. W. Borgland; J. Bregeon; A. Brez; M. Brigida; P. Bruel; R. Buehler; S. Buson; G. A. Caliandro; R. A. Cameron; S. Carrigan; J. M. Casandjian; E. Cavazzuti; C. Cecchi; Ö Çelik; A. Chekhtman; A. W. Chen; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; S. Colafrancesco; J. Conrad; S. Cutini; C. D. Dermer; F. De Palma; S. W. Digel; E. Do Couto E Silva; P. S. Drell; R. Dubois; D. Dumora; C. Farnier; C. Favuzzi; S. J. Fegan; E. C. Ferrara; W. B. Focke; M. Frailis; Y. Fukazawa; P. Fusco; F. Gargano; D. Gasparrini; N. Gehrels; B. Giebels; N. Giglietto; P. Giommi; F. Giordano; M. Giroletti; T. Glanzman; G. Godfrey; P. Grandi; I. A. Grenier; L. Guillemot; S. Guiriec; D. Hadasch; A. K. Harding; M. Hayashida; D. Horan; R. E. Hughes; R. Itoh; M. S. Jackson; G. Jóhannesson; A. S. Johnson; W. N. Johnson; T. Kamae; H. Katagiri; J. Kataoka; N. Kawai; J. Knödlseder; M. Kuss; J. Lande; L. Latronico; F. Longo; F. Loparco; B. Lott; M. N. Lovellette; P. Lubrano; G. M. Madejski; A. Makeev; M. N. Mazziotta; J. E. McEnery; S. McGlynn; C. Meurer; P. F. Michelson; W. Mitthumsiri; T. Mizuno; C. Monte; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; I. Nestoras; P. L. Nolan; J. P. Norris; E. Nuss; T. Ohsugi; A. Okumura; E. Orlando; J. F. Ormes; M. Ozaki; D. Paneque; J. H. Panetta; D. Parent; V. Pelassa; M. Pepe; M. Pesce-Rollins; F. Piron; T. A. Porter; S. Rainò; R. Rando; M. Razzano; A. Reimer; O. Reimer; L. C. Reyes; A. Y. Rodriguez; M. Roth; F. Ryde; H. F.W. Sadrozinski; R. Sambruna; A. Sander; R. Sato; C. Sgrò; M. S. Shaw; E. J. Siskind; P. D. Smith; G. Spandre; P. Spinelli; Stawarz; F. W. Stecker; M. S. Strickman; D. J. Suson; H. Takahashi; T. Takahashi; T. Tanaka; J. B. Thayer; J. G. Thayer; D. J. Thompson; O. Tibolla; D. F. Torres; G. Tosti; A. Tramacere; Y. Uchiyama; T. L. Usher; V. Vasileiou; N. Vilchez; M. Villata; V. Vitale; A. Von Kienlin; A. P. Waite; P. Wang; B. L. Winer; K. S. Wood; Z. Yang; T. Ylinen; M. Ziegler; F. Tavecchio; M. Sikora; P. Schady; P. Roming; M. M. Chester; L. Maraschi

doi:10.1088/0004-637X/716/1/835

Suzaku observations of luminous quasars: Revealing the nature of high-energy blazar emission in low-level activity states

A. A. Abdo, M. Ackermann, M. Ajello, E. Antolini, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. BruelR. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, S. Carrigan, J. M. Casandjian, E. Cavazzuti, C. Cecchi, Ö Çelik, A. Chekhtman, A. W. Chen, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, J. Conrad, S. Cutini, C. D. Dermer, F. De Palma, S. W. Digel, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, P. Grandi, I. A. Grenier, L. Guillemot, S. Guiriec, D. Hadasch, A. K. Harding, M. Hayashida, D. Horan, R. E. Hughes, R. Itoh, M. S. Jackson, G. Jóhannesson, A. S. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. N. Mazziotta, J. E. McEnery, S. McGlynn, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, I. Nestoras, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, A. Okumura, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, L. C. Reyes, A. Y. Rodriguez, M. Roth, F. Ryde, H. F.W. Sadrozinski, R. Sambruna, A. Sander, R. Sato, C. Sgrò, M. S. Shaw, E. J. Siskind, P. D. Smith, G. Spandre, P. Spinelli, Stawarz, F. W. Stecker, M. S. Strickman, D. J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, O. Tibolla, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, V. Vasileiou, N. Vilchez, M. Villata, V. Vitale, A. Von Kienlin, A. P. Waite, P. Wang, B. L. Winer, K. S. Wood, Z. Yang, T. Ylinen, M. Ziegler, F. Tavecchio, M. Sikora, P. Schady, P. Roming, M. M. Chester, L. Maraschi

Research output: Contribution to journal › Article › peer-review

27 Scopus citations

Abstract

We present the results from the Suzaku X-ray observations of five flat-spectrum radio quasars (FSRQs), namely PKS0208-512, Q0827+243, PKS1127-145, PKS1510-089, and 3C454.3. All these sources were additionally monitored simultaneously or quasi-simultaneously by the Fermi satellite in gamma rays and the Swift UVOT in the UV and optical bands, respectively. We constructed their broadband spectra covering the frequency range from 10¹⁴Hz up to 10²⁵Hz, and those reveal the nature of high-energy emission of luminous blazars in their low-activity states. The analyzed X-ray spectra are well fitted by a power-law model with photoelectric absorption. In the case of PKS0208-512, PKS1127-145, and 3C454.3, the X-ray continuum showed indication of hardening at low energies. Moreover, when compared with the previous X-ray observations, we see a significantly increasing contribution of low-energy photons to the total X-ray fluxes when the sources are getting fainter. The same behavior can be noted in the Suzaku data alone. A likely explanation involves a variable, flat-spectrum component produced via inverse-Compton emission, plus an additional, possibly steady soft X-ray component prominent when the source gets fainter. This soft X-ray excess is represented either by a steep power-law (photon indices Γ 3-5) or a blackbody-type emission with temperatures kT 0.1-0.2keV. We model the broadband spectra of the five observed FSRQs using synchrotron self-Compton and/or external-Compton radiation models. Our modeling suggests that the difference between the low- and high-activity states in luminous blazars is due to the different total kinetic power of the jet, most likely related to varying bulk Lorentz factor of the outflow within the blazar emission zone.

Original language	English
Pages (from-to)	835-849
Number of pages	15
Journal	Astrophysical Journal
Volume	716
Issue number	1
DOIs	https://doi.org/10.1088/0004-637X/716/1/835
State	Published - 2010
Externally published	Yes

Keywords

Galaxies: active
Galaxies: jets
Radiation mechanisms: non-thermal
X-rays: galaxies

Access to Document

10.1088/0004-637X/716/1/835

Cite this

Abdo, A. A., Ackermann, M., Ajello, M., Antolini, E., Baldini, L., Ballet, J., Barbiellini, G., Baring, M. G., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R. D., Bloom, E. D., Bonamente, E., Borgland, A. W., Bregeon, J., Brez, A., Brigida, M., ... Maraschi, L. (2010). Suzaku observations of luminous quasars: Revealing the nature of high-energy blazar emission in low-level activity states. Astrophysical Journal, 716(1), 835-849. https://doi.org/10.1088/0004-637X/716/1/835

@article{60b0a6c5bb2442a1b6c19f2d2515d76a,

title = "Suzaku observations of luminous quasars: Revealing the nature of high-energy blazar emission in low-level activity states",

abstract = "We present the results from the Suzaku X-ray observations of five flat-spectrum radio quasars (FSRQs), namely PKS0208-512, Q0827+243, PKS1127-145, PKS1510-089, and 3C454.3. All these sources were additionally monitored simultaneously or quasi-simultaneously by the Fermi satellite in gamma rays and the Swift UVOT in the UV and optical bands, respectively. We constructed their broadband spectra covering the frequency range from 1014Hz up to 1025Hz, and those reveal the nature of high-energy emission of luminous blazars in their low-activity states. The analyzed X-ray spectra are well fitted by a power-law model with photoelectric absorption. In the case of PKS0208-512, PKS1127-145, and 3C454.3, the X-ray continuum showed indication of hardening at low energies. Moreover, when compared with the previous X-ray observations, we see a significantly increasing contribution of low-energy photons to the total X-ray fluxes when the sources are getting fainter. The same behavior can be noted in the Suzaku data alone. A likely explanation involves a variable, flat-spectrum component produced via inverse-Compton emission, plus an additional, possibly steady soft X-ray component prominent when the source gets fainter. This soft X-ray excess is represented either by a steep power-law (photon indices Γ 3-5) or a blackbody-type emission with temperatures kT 0.1-0.2keV. We model the broadband spectra of the five observed FSRQs using synchrotron self-Compton and/or external-Compton radiation models. Our modeling suggests that the difference between the low- and high-activity states in luminous blazars is due to the different total kinetic power of the jet, most likely related to varying bulk Lorentz factor of the outflow within the blazar emission zone.",

keywords = "Galaxies: active, Galaxies: jets, Radiation mechanisms: non-thermal, X-rays: galaxies",

author = "Abdo, {A. A.} and M. Ackermann and M. Ajello and E. Antolini and L. Baldini and J. Ballet and G. Barbiellini and Baring, {M. G.} and D. Bastieri and K. Bechtol and R. Bellazzini and B. Berenji and Blandford, {R. D.} and Bloom, {E. D.} and E. Bonamente and Borgland, {A. W.} and J. Bregeon and A. Brez and M. Brigida and P. Bruel and R. Buehler and S. Buson and Caliandro, {G. A.} and Cameron, {R. A.} and S. Carrigan and Casandjian, {J. M.} and E. Cavazzuti and C. Cecchi and {\"O} {\c C}elik and A. Chekhtman and Chen, {A. W.} and J. Chiang and S. Ciprini and R. Claus and J. Cohen-Tanugi and S. Colafrancesco and J. Conrad and S. Cutini and Dermer, {C. D.} and {De Palma}, F. and Digel, {S. W.} and {Do Couto E Silva}, E. and Drell, {P. S.} and R. Dubois and D. Dumora and C. Farnier and C. Favuzzi and Fegan, {S. J.} and Ferrara, {E. C.} and Focke, {W. B.} and M. Frailis and Y. Fukazawa and P. Fusco and F. Gargano and D. Gasparrini and N. Gehrels and B. Giebels and N. Giglietto and P. Giommi and F. Giordano and M. Giroletti and T. Glanzman and G. Godfrey and P. Grandi and Grenier, {I. A.} and L. Guillemot and S. Guiriec and D. Hadasch and Harding, {A. K.} and M. Hayashida and D. Horan and Hughes, {R. E.} and R. Itoh and Jackson, {M. S.} and G. J{\'o}hannesson and Johnson, {A. S.} and Johnson, {W. N.} and T. Kamae and H. Katagiri and J. Kataoka and N. Kawai and J. Kn{\"o}dlseder and M. Kuss and J. Lande and L. Latronico and F. Longo and F. Loparco and B. Lott and Lovellette, {M. N.} and P. Lubrano and Madejski, {G. M.} and A. Makeev and Mazziotta, {M. N.} and McEnery, {J. E.} and S. McGlynn and C. Meurer and Michelson, {P. F.} and W. Mitthumsiri and T. Mizuno and C. Monte and Monzani, {M. E.} and A. Morselli and Moskalenko, {I. V.} and S. Murgia and I. Nestoras and Nolan, {P. L.} and Norris, {J. P.} and E. Nuss and T. Ohsugi and A. Okumura and E. Orlando and Ormes, {J. F.} and M. Ozaki and D. Paneque and Panetta, {J. H.} and D. Parent and V. Pelassa and M. Pepe and M. Pesce-Rollins and F. Piron and Porter, {T. A.} and S. Rain{\`o} and R. Rando and M. Razzano and A. Reimer and O. Reimer and Reyes, {L. C.} and Rodriguez, {A. Y.} and M. Roth and F. Ryde and Sadrozinski, {H. F.W.} and R. Sambruna and A. Sander and R. Sato and C. Sgr{\`o} and Shaw, {M. S.} and Siskind, {E. J.} and Smith, {P. D.} and G. Spandre and P. Spinelli and Stawarz and Stecker, {F. W.} and Strickman, {M. S.} and Suson, {D. J.} and H. Takahashi and T. Takahashi and T. Tanaka and Thayer, {J. B.} and Thayer, {J. G.} and Thompson, {D. J.} and O. Tibolla and Torres, {D. F.} and G. Tosti and A. Tramacere and Y. Uchiyama and Usher, {T. L.} and V. Vasileiou and N. Vilchez and M. Villata and V. Vitale and {Von Kienlin}, A. and Waite, {A. P.} and P. Wang and Winer, {B. L.} and Wood, {K. S.} and Z. Yang and T. Ylinen and M. Ziegler and F. Tavecchio and M. Sikora and P. Schady and P. Roming and Chester, {M. M.} and L. Maraschi",

year = "2010",

doi = "10.1088/0004-637X/716/1/835",

language = "English",

volume = "716",

pages = "835--849",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "1",

}

Abdo, AA, Ackermann, M, Ajello, M, Antolini, E, Baldini, L, Ballet, J, Barbiellini, G, Baring, MG, Bastieri, D, Bechtol, K, Bellazzini, R, Berenji, B, Blandford, RD, Bloom, ED, Bonamente, E, Borgland, AW, Bregeon, J, Brez, A, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Carrigan, S, Casandjian, JM, Cavazzuti, E, Cecchi, C, Çelik, Ö, Chekhtman, A, Chen, AW, Chiang, J, Ciprini, S, Claus, R, Cohen-Tanugi, J, Colafrancesco, S, Conrad, J, Cutini, S, Dermer, CD, De Palma, F, Digel, SW, Do Couto E Silva, E, Drell, PS, Dubois, R, Dumora, D, Farnier, C, Favuzzi, C, Fegan, SJ, Ferrara, EC, Focke, WB, Frailis, M, Fukazawa, Y, Fusco, P, Gargano, F, Gasparrini, D, Gehrels, N, Giebels, B, Giglietto, N, Giommi, P, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grandi, P, Grenier, IA, Guillemot, L, Guiriec, S, Hadasch, D, Harding, AK, Hayashida, M, Horan, D, Hughes, RE, Itoh, R, Jackson, MS, Jóhannesson, G, Johnson, AS, Johnson, WN, Kamae, T, Katagiri, H, Kataoka, J, Kawai, N, Knödlseder, J, Kuss, M, Lande, J, Latronico, L, Longo, F, Loparco, F, Lott, B, Lovellette, MN, Lubrano, P, Madejski, GM, Makeev, A, Mazziotta, MN, McEnery, JE, McGlynn, S, Meurer, C, Michelson, PF, Mitthumsiri, W, Mizuno, T, Monte, C, Monzani, ME, Morselli, A, Moskalenko, IV, Murgia, S, Nestoras, I, Nolan, PL, Norris, JP, Nuss, E, Ohsugi, T, Okumura, A, Orlando, E, Ormes, JF, Ozaki, M, Paneque, D, Panetta, JH, Parent, D, Pelassa, V, Pepe, M, Pesce-Rollins, M, Piron, F, Porter, TA, Rainò, S, Rando, R, Razzano, M, Reimer, A, Reimer, O, Reyes, LC, Rodriguez, AY, Roth, M, Ryde, F, Sadrozinski, HFW, Sambruna, R, Sander, A, Sato, R, Sgrò, C, Shaw, MS, Siskind, EJ, Smith, PD, Spandre, G, Spinelli, P, Stawarz, Stecker, FW, Strickman, MS, Suson, DJ, Takahashi, H, Takahashi, T, Tanaka, T, Thayer, JB, Thayer, JG, Thompson, DJ, Tibolla, O, Torres, DF, Tosti, G, Tramacere, A, Uchiyama, Y, Usher, TL, Vasileiou, V, Vilchez, N, Villata, M, Vitale, V, Von Kienlin, A, Waite, AP, Wang, P, Winer, BL, Wood, KS, Yang, Z, Ylinen, T, Ziegler, M, Tavecchio, F, Sikora, M, Schady, P, Roming, P, Chester, MM & Maraschi, L 2010, 'Suzaku observations of luminous quasars: Revealing the nature of high-energy blazar emission in low-level activity states', Astrophysical Journal, vol. 716, no. 1, pp. 835-849. https://doi.org/10.1088/0004-637X/716/1/835

TY - JOUR

T1 - Suzaku observations of luminous quasars

T2 - Revealing the nature of high-energy blazar emission in low-level activity states

AU - Abdo, A. A.

AU - Ackermann, M.

AU - Ajello, M.

AU - Antolini, E.

AU - Baldini, L.

AU - Ballet, J.

AU - Barbiellini, G.

AU - Baring, M. G.

AU - Bastieri, D.

AU - Bechtol, K.

AU - Bellazzini, R.

AU - Berenji, B.

AU - Blandford, R. D.

AU - Bloom, E. D.

AU - Bonamente, E.

AU - Borgland, A. W.

AU - Bregeon, J.

AU - Brez, A.

AU - Brigida, M.

AU - Bruel, P.

AU - Buehler, R.

AU - Buson, S.

AU - Caliandro, G. A.

AU - Cameron, R. A.

AU - Carrigan, S.

AU - Casandjian, J. M.

AU - Cavazzuti, E.

AU - Cecchi, C.

AU - Çelik, Ö

AU - Chekhtman, A.

AU - Chen, A. W.

AU - Chiang, J.

AU - Ciprini, S.

AU - Claus, R.

AU - Cohen-Tanugi, J.

AU - Colafrancesco, S.

AU - Conrad, J.

AU - Cutini, S.

AU - Dermer, C. D.

AU - De Palma, F.

AU - Digel, S. W.

AU - Do Couto E Silva, E.

AU - Drell, P. S.

AU - Dubois, R.

AU - Dumora, D.

AU - Farnier, C.

AU - Favuzzi, C.

AU - Fegan, S. J.

AU - Ferrara, E. C.

AU - Focke, W. B.

AU - Frailis, M.

AU - Fukazawa, Y.

AU - Fusco, P.

AU - Gargano, F.

AU - Gasparrini, D.

AU - Gehrels, N.

AU - Giebels, B.

AU - Giglietto, N.

AU - Giommi, P.

AU - Giordano, F.

AU - Giroletti, M.

AU - Glanzman, T.

AU - Godfrey, G.

AU - Grandi, P.

AU - Grenier, I. A.

AU - Guillemot, L.

AU - Guiriec, S.

AU - Hadasch, D.

AU - Harding, A. K.

AU - Hayashida, M.

AU - Horan, D.

AU - Hughes, R. E.

AU - Itoh, R.

AU - Jackson, M. S.

AU - Jóhannesson, G.

AU - Johnson, A. S.

AU - Johnson, W. N.

AU - Kamae, T.

AU - Katagiri, H.

AU - Kataoka, J.

AU - Kawai, N.

AU - Knödlseder, J.

AU - Kuss, M.

AU - Lande, J.

AU - Latronico, L.

AU - Longo, F.

AU - Loparco, F.

AU - Lott, B.

AU - Lovellette, M. N.

AU - Lubrano, P.

AU - Madejski, G. M.

AU - Makeev, A.

AU - Mazziotta, M. N.

AU - McEnery, J. E.

AU - McGlynn, S.

AU - Meurer, C.

AU - Michelson, P. F.

AU - Mitthumsiri, W.

AU - Mizuno, T.

AU - Monte, C.

AU - Monzani, M. E.

AU - Morselli, A.

AU - Moskalenko, I. V.

AU - Murgia, S.

AU - Nestoras, I.

AU - Nolan, P. L.

AU - Norris, J. P.

AU - Nuss, E.

AU - Ohsugi, T.

AU - Okumura, A.

AU - Orlando, E.

AU - Ormes, J. F.

AU - Ozaki, M.

AU - Paneque, D.

AU - Panetta, J. H.

AU - Parent, D.

AU - Pelassa, V.

AU - Pepe, M.

AU - Pesce-Rollins, M.

AU - Piron, F.

AU - Porter, T. A.

AU - Rainò, S.

AU - Rando, R.

AU - Razzano, M.

AU - Reimer, A.

AU - Reimer, O.

AU - Reyes, L. C.

AU - Rodriguez, A. Y.

AU - Roth, M.

AU - Ryde, F.

AU - Sadrozinski, H. F.W.

AU - Sambruna, R.

AU - Sander, A.

AU - Sato, R.

AU - Sgrò, C.

AU - Shaw, M. S.

AU - Siskind, E. J.

AU - Smith, P. D.

AU - Spandre, G.

AU - Spinelli, P.

AU - Stawarz,

AU - Stecker, F. W.

AU - Strickman, M. S.

AU - Suson, D. J.

AU - Takahashi, H.

AU - Takahashi, T.

AU - Tanaka, T.

AU - Thayer, J. B.

AU - Thayer, J. G.

AU - Thompson, D. J.

AU - Tibolla, O.

AU - Torres, D. F.

AU - Tosti, G.

AU - Tramacere, A.

AU - Uchiyama, Y.

AU - Usher, T. L.

AU - Vasileiou, V.

AU - Vilchez, N.

AU - Villata, M.

AU - Vitale, V.

AU - Von Kienlin, A.

AU - Waite, A. P.

AU - Wang, P.

AU - Winer, B. L.

AU - Wood, K. S.

AU - Yang, Z.

AU - Ylinen, T.

AU - Ziegler, M.

AU - Tavecchio, F.

AU - Sikora, M.

AU - Schady, P.

AU - Roming, P.

AU - Chester, M. M.

AU - Maraschi, L.

PY - 2010

Y1 - 2010

N2 - We present the results from the Suzaku X-ray observations of five flat-spectrum radio quasars (FSRQs), namely PKS0208-512, Q0827+243, PKS1127-145, PKS1510-089, and 3C454.3. All these sources were additionally monitored simultaneously or quasi-simultaneously by the Fermi satellite in gamma rays and the Swift UVOT in the UV and optical bands, respectively. We constructed their broadband spectra covering the frequency range from 1014Hz up to 1025Hz, and those reveal the nature of high-energy emission of luminous blazars in their low-activity states. The analyzed X-ray spectra are well fitted by a power-law model with photoelectric absorption. In the case of PKS0208-512, PKS1127-145, and 3C454.3, the X-ray continuum showed indication of hardening at low energies. Moreover, when compared with the previous X-ray observations, we see a significantly increasing contribution of low-energy photons to the total X-ray fluxes when the sources are getting fainter. The same behavior can be noted in the Suzaku data alone. A likely explanation involves a variable, flat-spectrum component produced via inverse-Compton emission, plus an additional, possibly steady soft X-ray component prominent when the source gets fainter. This soft X-ray excess is represented either by a steep power-law (photon indices Γ 3-5) or a blackbody-type emission with temperatures kT 0.1-0.2keV. We model the broadband spectra of the five observed FSRQs using synchrotron self-Compton and/or external-Compton radiation models. Our modeling suggests that the difference between the low- and high-activity states in luminous blazars is due to the different total kinetic power of the jet, most likely related to varying bulk Lorentz factor of the outflow within the blazar emission zone.

AB - We present the results from the Suzaku X-ray observations of five flat-spectrum radio quasars (FSRQs), namely PKS0208-512, Q0827+243, PKS1127-145, PKS1510-089, and 3C454.3. All these sources were additionally monitored simultaneously or quasi-simultaneously by the Fermi satellite in gamma rays and the Swift UVOT in the UV and optical bands, respectively. We constructed their broadband spectra covering the frequency range from 1014Hz up to 1025Hz, and those reveal the nature of high-energy emission of luminous blazars in their low-activity states. The analyzed X-ray spectra are well fitted by a power-law model with photoelectric absorption. In the case of PKS0208-512, PKS1127-145, and 3C454.3, the X-ray continuum showed indication of hardening at low energies. Moreover, when compared with the previous X-ray observations, we see a significantly increasing contribution of low-energy photons to the total X-ray fluxes when the sources are getting fainter. The same behavior can be noted in the Suzaku data alone. A likely explanation involves a variable, flat-spectrum component produced via inverse-Compton emission, plus an additional, possibly steady soft X-ray component prominent when the source gets fainter. This soft X-ray excess is represented either by a steep power-law (photon indices Γ 3-5) or a blackbody-type emission with temperatures kT 0.1-0.2keV. We model the broadband spectra of the five observed FSRQs using synchrotron self-Compton and/or external-Compton radiation models. Our modeling suggests that the difference between the low- and high-activity states in luminous blazars is due to the different total kinetic power of the jet, most likely related to varying bulk Lorentz factor of the outflow within the blazar emission zone.

KW - Galaxies: active

KW - Galaxies: jets

KW - Radiation mechanisms: non-thermal

KW - X-rays: galaxies

UR - http://www.scopus.com/inward/record.url?scp=77952974205&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/716/1/835

DO - 10.1088/0004-637X/716/1/835

M3 - Article

AN - SCOPUS:77952974205

SN - 0004-637X

VL - 716

SP - 835

EP - 849

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

ER -

Suzaku observations of luminous quasars: Revealing the nature of high-energy blazar emission in low-level activity states

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