Discovery of TeV γ-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift
A. Abramowski, F. Acero, A. G. Akhperjanian, G. Anton, S. Balenderan, A. Balzer, A. Barnacka, Y. Becherini, J. Becker Tjus, B. Behera, K. Bernlöhr, E. Birsin, J. Biteau, A. Bochow, C. Boisson, J. Bolmont, P. Bordas, J. Brucker, F. Brun, P. BrunT. Bulik, S. Carrigan, S. Casanova, M. Cerruti, P. M. Chadwick, R. C G Chaves, A. Cheesebrough, S. Colafrancesco, G. Cologna, J. Conrad, C. Couturier, M. Dalton, M. K. Daniel, I. D. Davids, B. Degrange, C. Deil, P. Dewilt, H. J. Dickinson, A. Djannati-Ataï, W. Domainko, L. O C Drury, G. Dubus, K. Dutson, J. Dyks, M. Dyrda, K. Egberts, P. Eger, P. Espigat, L. Fallon, C. Farnier, S. Fegan, F. Feinstein, M. V. Fernandes, D. Fernandez, A. Fiasson, G. Fontaine, A. Förster, M. Füßling, M. Gajdus, Y. A. Gallant, T. Garrigoux, H. Gast, B. Giebels, J. F. Glicenstein, B. Glück, D. Göring, M. H. Grondin, M. Grudzińska, S. Häffner, J. D. Hague, J. Hahn, D. Hampf, J. Harris, S. Heinz, G. Heinzelmann, G. Henri, G. Hermann, A. Hillert, J. A. Hinton, W. Hofmann, P. Hofverberg, M. Holler, D. Horns, A. Jacholkowska, C. Jahn, M. Jamrozy, I. Jung, M. A. Kastendieck, K. Katarzyński, U. Katz, S. Kaufmann, B. Khélifi, S. Klepser, D. Klochkov, W. Kluåniak, T. Kneiske, D. Kolitzus, Nu Komin, K. Kosack, R. Kossakowski, F. Krayzel, P. P. Krüger, H. Laffon, G. Lamanna, J. Lefaucheur, M. Lemoine-Goumard, J. P. Lenain, D. Lennarz, T. Lohse, A. Lopatin, C. C. Lu, V. Marandon, A. Marcowith, J. Masbou, G. Maurin, N. Maxted, M. Mayer, T. J L McComb, M. C. Medina, J. Méhault, U. Menzler, R. Moderski, M. Mohamed, E. Moulin, C. L. Naumann, M. Naumann-Godo, M. De Naurois, D. Nedbal, N. Nguyen, J. Niemiec, S. J. Nolan, S. Ohm, E. De Oña Wilhelmi, B. Opitz, M. Ostrowski, I. Oya, M. Panter, R. D. Parsons, M. Paz Arribas, N. W. Pekeur, G. Pelletier, J. Perez, P. O. Petrucci, B. Peyaud, S. Pita, G. Pühlhofer, M. Punch, A. Quirrenbach, S. Raab, M. Raue, A. Reimer, O. Reimer, M. Renaud, R. De Los Reyes, F. Rieger, J. Ripken, L. Rob, S. Rosier-Lees, G. Rowell, B. Rudak, C. B. Rulten, V. Sahakian, D. A. Sanchez, A. Santangelo, R. Schlickeiser, A. Schulz, U. Schwanke, S. Schwarzburg, S. Schwemmer, F. Sheidaei, J. L. Skilton, H. Sol, G. Spengler, L. Stawarz, R. Steenkamp, C. Stegmann, F. Stinzing, K. Stycz, I. Sushch, A. Szostek, J. P. Tavernet, R. Terrier, M. Tluczykont, C. Trichard, K. Valerius, C. Van Eldik, G. Vasileiadis, C. Venter, A. Viana, P. Vincent, H. J. Völk, F. Volpe, S. Vorobiov, M. Vorster, S. J. Wagner, M. Ward, R. White, A. Wierzcholska, D. Wouters, M. Zacharias, A. Zajczyk, A. A. Zdziarski, A. Zech, H. S. Zechlin, D. Pelat
Physics and Astronomy (Twin Cities)
Very high-energy γ-ray emission from PKS 0447-439 was detected with the H.E.S.S. Cherenkov telescope array in December 2009. This blazar is one of the brightest extragalactic objects in the Fermi bright source list and has a hard spectrum in the MeV to GeV range. In the TeV range, a photon index of 3.89 ± 0.37 (stat) ±0.22 (sys) and a flux normalisation at 1 TeV, Φ1 TeV = (3.5 ± 1.1(stat) ± 0.9(sys)) × 10-13 cm-2 s-1 TeV-1 were found. The detection with H.E.S.S. triggered observations in the X-ray band with the Swift and RXTE telescopes. Simultaneous UV and optical data from Swift UVOT and data from the optical telescopes ATOM and ROTSE are also available. The spectrum and light curve measured with H.E.S.S. are presented and compared to the multi-wavelength data at lower energies. A rapid flare is seen in the Swift XRT and RXTE data, together with a flux variation in the UV band, at a time scale of the order of one day. A firm upper limit of z < 0.59 on the redshift of PKS 0447-439 is derived from the combined Fermi-LAT and H.E.S.S. data, given the assumptions that there is no upturn in the intrinsic spectrum above the Fermi-LAT energy range and that absorption on the extragalactic background light (EBL) is not weaker than the lower limit provided by current models. The spectral energy distribution is well described by a simple one-zone synchrotron self-Compton scenario, if the redshift of the source is less than z ≠0.4.
The support of the Namibian authorities and of the University of Namibia in facilitating the construction and operation of H.E.S.S. is gratefully acknowledged, as is the support by the German Ministry for Education and Research (BMBF), the Max Planck Society, the German Research Foundation (DFG), the French Ministry for Research, the CNRS-IN2P3 and the Astroparticle Interdisciplinary Programme of the CNRS, the UK Science and Technology Facilities Council (STFC), the IPNP of the Charles University, the Czech Science Foundation, the Polish Ministry of Science and Higher Education, the South African Department of Science and Technology and National Research Foundation, and by the University of Namibia. We appreciate the excellent work of the technical support staff in Berlin, Durham, Hamburg, Heidelberg, Palaiseau, Paris, Saclay, and in Namibia in the construction and operation of the equipment. This research made use of the NASA/IPAC Extragalactic Database (NED) and of the SIMBAD Astronomical Database. The authors thank the RXTE team for their prompt response to our ToO request and the professional interactions that followed. The authors acknowledge the use of the publicly available Swift data, as well as the public HEASARC software packages. The authors wish to thank H. Landt and M. Véron-Cetty for very helpful discussions on the available redshift estimates of the source.
BL Lacertae objects: individual: PKS 0447-439
Galaxies: active
Gamma rays: galaxies
Radiation mechanisms: non-thermal
10.1051/0004-6361/201321108
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Abramowski, A., Acero, F., Akhperjanian, A. G., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Becker Tjus, J., Behera, B., Bernlöhr, K., Birsin, E., Biteau, J., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., ... Pelat, D. (2013). Discovery of TeV γ-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift. Astronomy and Astrophysics, 552, [A118]. https://doi.org/10.1051/0004-6361/201321108
Discovery of TeV γ-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift. / Abramowski, A.; Acero, F.; Akhperjanian, A. G. et al.
In: Astronomy and Astrophysics, Vol. 552, A118, 2013.
Abramowski, A, Acero, F, Akhperjanian, AG, Anton, G, Balenderan, S, Balzer, A, Barnacka, A, Becherini, Y, Becker Tjus, J, Behera, B, Bernlöhr, K, Birsin, E, Biteau, J, Bochow, A, Boisson, C, Bolmont, J, Bordas, P, Brucker, J, Brun, F, Brun, P, Bulik, T, Carrigan, S, Casanova, S, Cerruti, M, Chadwick, PM, Chaves, RCG, Cheesebrough, A, Colafrancesco, S, Cologna, G, Conrad, J, Couturier, C, Dalton, M, Daniel, MK, Davids, ID, Degrange, B, Deil, C, Dewilt, P, Dickinson, HJ, Djannati-Ataï, A, Domainko, W, Drury, LOC, Dubus, G, Dutson, K, Dyks, J, Dyrda, M, Egberts, K, Eger, P, Espigat, P, Fallon, L, Farnier, C, Fegan, S, Feinstein, F, Fernandes, MV, Fernandez, D, Fiasson, A, Fontaine, G, Förster, A, Füßling, M, Gajdus, M, Gallant, YA, Garrigoux, T, Gast, H, Giebels, B, Glicenstein, JF, Glück, B, Göring, D, Grondin, MH, Grudzińska, M, Häffner, S, Hague, JD, Hahn, J, Hampf, D, Harris, J, Heinz, S, Heinzelmann, G, Henri, G, Hermann, G, Hillert, A, Hinton, JA, Hofmann, W, Hofverberg, P, Holler, M, Horns, D, Jacholkowska, A, Jahn, C, Jamrozy, M, Jung, I, Kastendieck, MA, Katarzyński, K, Katz, U, Kaufmann, S, Khélifi, B, Klepser, S, Klochkov, D, Kluåniak, W, Kneiske, T, Kolitzus, D, Komin, N, Kosack, K, Kossakowski, R, Krayzel, F, Krüger, PP, Laffon, H, Lamanna, G, Lefaucheur, J, Lemoine-Goumard, M, Lenain, JP, Lennarz, D, Lohse, T, Lopatin, A, Lu, CC, Marandon, V, Marcowith, A, Masbou, J, Maurin, G, Maxted, N, Mayer, M, McComb, TJL, Medina, MC, Méhault, J, Menzler, U, Moderski, R, Mohamed, M, Moulin, E, Naumann, CL, Naumann-Godo, M, De Naurois, M, Nedbal, D, Nguyen, N, Niemiec, J, Nolan, SJ, Ohm, S, De Oña Wilhelmi, E, Opitz, B, Ostrowski, M, Oya, I, Panter, M, Parsons, RD, Paz Arribas, M, Pekeur, NW, Pelletier, G, Perez, J, Petrucci, PO, Peyaud, B, Pita, S, Pühlhofer, G, Punch, M, Quirrenbach, A, Raab, S, Raue, M, Reimer, A, Reimer, O, Renaud, M, De Los Reyes, R, Rieger, F, Ripken, J, Rob, L, Rosier-Lees, S, Rowell, G, Rudak, B, Rulten, CB, Sahakian, V, Sanchez, DA, Santangelo, A, Schlickeiser, R, Schulz, A, Schwanke, U, Schwarzburg, S, Schwemmer, S, Sheidaei, F, Skilton, JL, Sol, H, Spengler, G, Stawarz, L, Steenkamp, R, Stegmann, C, Stinzing, F, Stycz, K, Sushch, I, Szostek, A, Tavernet, JP, Terrier, R, Tluczykont, M, Trichard, C, Valerius, K, Van Eldik, C, Vasileiadis, G, Venter, C, Viana, A, Vincent, P, Völk, HJ, Volpe, F, Vorobiov, S, Vorster, M, Wagner, SJ, Ward, M, White, R, Wierzcholska, A, Wouters, D, Zacharias, M, Zajczyk, A, Zdziarski, AA, Zech, A, Zechlin, HS & Pelat, D 2013, 'Discovery of TeV γ-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift', Astronomy and Astrophysics, vol. 552, A118. https://doi.org/10.1051/0004-6361/201321108
Abramowski A, Acero F, Akhperjanian AG, Anton G, Balenderan S, Balzer A et al. Discovery of TeV γ-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift. Astronomy and Astrophysics. 2013;552:A118. doi: 10.1051/0004-6361/201321108
Abramowski, A. ; Acero, F. ; Akhperjanian, A. G. et al. / Discovery of TeV γ-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift. In: Astronomy and Astrophysics. 2013 ; Vol. 552.
@article{255431229f2644f19426625694b95857,
title = "Discovery of TeV γ-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift",
abstract = "Very high-energy γ-ray emission from PKS 0447-439 was detected with the H.E.S.S. Cherenkov telescope array in December 2009. This blazar is one of the brightest extragalactic objects in the Fermi bright source list and has a hard spectrum in the MeV to GeV range. In the TeV range, a photon index of 3.89 ± 0.37 (stat) ±0.22 (sys) and a flux normalisation at 1 TeV, Φ1 TeV = (3.5 ± 1.1(stat) ± 0.9(sys)) × 10-13 cm-2 s-1 TeV-1 were found. The detection with H.E.S.S. triggered observations in the X-ray band with the Swift and RXTE telescopes. Simultaneous UV and optical data from Swift UVOT and data from the optical telescopes ATOM and ROTSE are also available. The spectrum and light curve measured with H.E.S.S. are presented and compared to the multi-wavelength data at lower energies. A rapid flare is seen in the Swift XRT and RXTE data, together with a flux variation in the UV band, at a time scale of the order of one day. A firm upper limit of z < 0.59 on the redshift of PKS 0447-439 is derived from the combined Fermi-LAT and H.E.S.S. data, given the assumptions that there is no upturn in the intrinsic spectrum above the Fermi-LAT energy range and that absorption on the extragalactic background light (EBL) is not weaker than the lower limit provided by current models. The spectral energy distribution is well described by a simple one-zone synchrotron self-Compton scenario, if the redshift of the source is less than z {\^a}‰ 0.4.",
keywords = "BL Lacertae objects: individual: PKS 0447-439, Galaxies: active, Gamma rays: galaxies, Radiation mechanisms: non-thermal",
author = "A. Abramowski and F. Acero and Akhperjanian, {A. G.} and G. Anton and S. Balenderan and A. Balzer and A. Barnacka and Y. Becherini and {Becker Tjus}, J. and B. Behera and K. Bernl{\"o}hr and E. Birsin and J. Biteau and A. Bochow and C. Boisson and J. Bolmont and P. Bordas and J. Brucker and F. Brun and P. Brun and T. Bulik and S. Carrigan and S. Casanova and M. Cerruti and Chadwick, {P. M.} and Chaves, {R. C G} and A. Cheesebrough and S. Colafrancesco and G. Cologna and J. Conrad and C. Couturier and M. Dalton and Daniel, {M. K.} and Davids, {I. D.} and B. Degrange and C. Deil and P. Dewilt and Dickinson, {H. J.} and A. Djannati-Ata{\"i} and W. Domainko and Drury, {L. O C} and G. Dubus and K. Dutson and J. Dyks and M. Dyrda and K. Egberts and P. Eger and P. Espigat and L. Fallon and C. Farnier and S. Fegan and F. Feinstein and Fernandes, {M. V.} and D. Fernandez and A. Fiasson and G. Fontaine and A. F{\"o}rster and M. F{\"u}{\ss}ling and M. Gajdus and Gallant, {Y. A.} and T. Garrigoux and H. Gast and B. Giebels and Glicenstein, {J. F.} and B. Gl{\"u}ck and D. G{\"o}ring and Grondin, {M. H.} and M. Grudzi{\'n}ska and S. H{\"a}ffner and Hague, {J. D.} and J. Hahn and D. Hampf and J. Harris and S. Heinz and G. Heinzelmann and G. Henri and G. Hermann and A. Hillert and Hinton, {J. A.} and W. Hofmann and P. Hofverberg and M. Holler and D. Horns and A. Jacholkowska and C. Jahn and M. Jamrozy and I. Jung and Kastendieck, {M. A.} and K. Katarzy{\'n}ski and U. Katz and S. Kaufmann and B. Kh{\'e}lifi and S. Klepser and D. Klochkov and W. Klu{\aa}niak and T. Kneiske and D. Kolitzus and Nu Komin and K. Kosack and R. Kossakowski and F. Krayzel and Kr{\"u}ger, {P. P.} and H. Laffon and G. Lamanna and J. Lefaucheur and M. Lemoine-Goumard and Lenain, {J. P.} and D. Lennarz and T. Lohse and A. Lopatin and Lu, {C. C.} and V. Marandon and A. Marcowith and J. Masbou and G. Maurin and N. Maxted and M. Mayer and McComb, {T. J L} and Medina, {M. C.} and J. M{\'e}hault and U. Menzler and R. Moderski and M. Mohamed and E. Moulin and Naumann, {C. L.} and M. Naumann-Godo and {De Naurois}, M. and D. Nedbal and N. Nguyen and J. Niemiec and Nolan, {S. J.} and S. Ohm and {De O{\~n}a Wilhelmi}, E. and B. Opitz and M. Ostrowski and I. Oya and M. Panter and Parsons, {R. D.} and {Paz Arribas}, M. and Pekeur, {N. W.} and G. Pelletier and J. Perez and Petrucci, {P. O.} and B. Peyaud and S. Pita and G. P{\"u}hlhofer and M. Punch and A. Quirrenbach and S. Raab and M. Raue and A. Reimer and O. Reimer and M. Renaud and {De Los Reyes}, R. and F. Rieger and J. Ripken and L. Rob and S. Rosier-Lees and G. Rowell and B. Rudak and Rulten, {C. B.} and V. Sahakian and Sanchez, {D. A.} and A. Santangelo and R. Schlickeiser and A. Schulz and U. Schwanke and S. Schwarzburg and S. Schwemmer and F. Sheidaei and Skilton, {J. L.} and H. Sol and G. Spengler and L. Stawarz and R. Steenkamp and C. Stegmann and F. Stinzing and K. Stycz and I. Sushch and A. Szostek and Tavernet, {J. P.} and R. Terrier and M. Tluczykont and C. Trichard and K. Valerius and {Van Eldik}, C. and G. Vasileiadis and C. Venter and A. Viana and P. Vincent and V{\"o}lk, {H. J.} and F. Volpe and S. Vorobiov and M. Vorster and Wagner, {S. J.} and M. Ward and R. White and A. Wierzcholska and D. Wouters and M. Zacharias and A. Zajczyk and Zdziarski, {A. A.} and A. Zech and Zechlin, {H. S.} and D. Pelat",
note = "Funding Information: The support of the Namibian authorities and of the University of Namibia in facilitating the construction and operation of H.E.S.S. is gratefully acknowledged, as is the support by the German Ministry for Education and Research (BMBF), the Max Planck Society, the German Research Foundation (DFG), the French Ministry for Research, the CNRS-IN2P3 and the Astroparticle Interdisciplinary Programme of the CNRS, the UK Science and Technology Facilities Council (STFC), the IPNP of the Charles University, the Czech Science Foundation, the Polish Ministry of Science and Higher Education, the South African Department of Science and Technology and National Research Foundation, and by the University of Namibia. We appreciate the excellent work of the technical support staff in Berlin, Durham, Hamburg, Heidelberg, Palaiseau, Paris, Saclay, and in Namibia in the construction and operation of the equipment. This research made use of the NASA/IPAC Extragalactic Database (NED) and of the SIMBAD Astronomical Database. The authors thank the RXTE team for their prompt response to our ToO request and the professional interactions that followed. The authors acknowledge the use of the publicly available Swift data, as well as the public HEASARC software packages. The authors wish to thank H. Landt and M. V{\'e}ron-Cetty for very helpful discussions on the available redshift estimates of the source.",
doi = "10.1051/0004-6361/201321108",
journal = "Astronomy and Astrophysics",
publisher = "EDP Sciences",
T1 - Discovery of TeV γ-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift
AU - Abramowski, A.
AU - Acero, F.
AU - Akhperjanian, A. G.
AU - Anton, G.
AU - Balenderan, S.
AU - Balzer, A.
AU - Barnacka, A.
AU - Becherini, Y.
AU - Becker Tjus, J.
AU - Behera, B.
AU - Bernlöhr, K.
AU - Birsin, E.
AU - Biteau, J.
AU - Bochow, A.
AU - Boisson, C.
AU - Bolmont, J.
AU - Bordas, P.
AU - Brucker, J.
AU - Brun, F.
AU - Brun, P.
AU - Bulik, T.
AU - Carrigan, S.
AU - Casanova, S.
AU - Cerruti, M.
AU - Chadwick, P. M.
AU - Chaves, R. C G
AU - Cheesebrough, A.
AU - Colafrancesco, S.
AU - Cologna, G.
AU - Conrad, J.
AU - Couturier, C.
AU - Dalton, M.
AU - Daniel, M. K.
AU - Davids, I. D.
AU - Degrange, B.
AU - Deil, C.
AU - Dewilt, P.
AU - Dickinson, H. J.
AU - Djannati-Ataï, A.
AU - Domainko, W.
AU - Drury, L. O C
AU - Dubus, G.
AU - Dutson, K.
AU - Dyks, J.
AU - Dyrda, M.
AU - Egberts, K.
AU - Eger, P.
AU - Espigat, P.
AU - Fallon, L.
AU - Farnier, C.
AU - Fegan, S.
AU - Feinstein, F.
AU - Fernandes, M. V.
AU - Fernandez, D.
AU - Fiasson, A.
AU - Fontaine, G.
AU - Förster, A.
AU - Füßling, M.
AU - Gajdus, M.
AU - Gallant, Y. A.
AU - Garrigoux, T.
AU - Gast, H.
AU - Giebels, B.
AU - Glicenstein, J. F.
AU - Glück, B.
AU - Göring, D.
AU - Grondin, M. H.
AU - Grudzińska, M.
AU - Häffner, S.
AU - Hague, J. D.
AU - Hahn, J.
AU - Hampf, D.
AU - Harris, J.
AU - Heinz, S.
AU - Heinzelmann, G.
AU - Henri, G.
AU - Hermann, G.
AU - Hillert, A.
AU - Hinton, J. A.
AU - Hofmann, W.
AU - Hofverberg, P.
AU - Holler, M.
AU - Horns, D.
AU - Jacholkowska, A.
AU - Jahn, C.
AU - Jamrozy, M.
AU - Jung, I.
AU - Kastendieck, M. A.
AU - Katarzyński, K.
AU - Katz, U.
AU - Kaufmann, S.
AU - Khélifi, B.
AU - Klepser, S.
AU - Klochkov, D.
AU - Kluåniak, W.
AU - Kneiske, T.
AU - Kolitzus, D.
AU - Komin, Nu
AU - Kosack, K.
AU - Kossakowski, R.
AU - Krayzel, F.
AU - Krüger, P. P.
AU - Laffon, H.
AU - Lamanna, G.
AU - Lefaucheur, J.
AU - Lemoine-Goumard, M.
AU - Lenain, J. P.
AU - Lennarz, D.
AU - Lohse, T.
AU - Lopatin, A.
AU - Lu, C. C.
AU - Marandon, V.
AU - Marcowith, A.
AU - Masbou, J.
AU - Maurin, G.
AU - Maxted, N.
AU - Mayer, M.
AU - McComb, T. J L
AU - Medina, M. C.
AU - Méhault, J.
AU - Menzler, U.
AU - Moderski, R.
AU - Mohamed, M.
AU - Moulin, E.
AU - Naumann, C. L.
AU - Naumann-Godo, M.
AU - De Naurois, M.
AU - Nedbal, D.
AU - Nguyen, N.
AU - Niemiec, J.
AU - Nolan, S. J.
AU - Ohm, S.
AU - De Oña Wilhelmi, E.
AU - Opitz, B.
AU - Ostrowski, M.
AU - Oya, I.
AU - Panter, M.
AU - Parsons, R. D.
AU - Paz Arribas, M.
AU - Pekeur, N. W.
AU - Pelletier, G.
AU - Perez, J.
AU - Petrucci, P. O.
AU - Peyaud, B.
AU - Pita, S.
AU - Pühlhofer, G.
AU - Punch, M.
AU - Quirrenbach, A.
AU - Raab, S.
AU - Raue, M.
AU - Reimer, A.
AU - Reimer, O.
AU - Renaud, M.
AU - De Los Reyes, R.
AU - Rieger, F.
AU - Ripken, J.
AU - Rob, L.
AU - Rosier-Lees, S.
AU - Rowell, G.
AU - Rudak, B.
AU - Rulten, C. B.
AU - Sahakian, V.
AU - Sanchez, D. A.
AU - Santangelo, A.
AU - Schlickeiser, R.
AU - Schulz, A.
AU - Schwanke, U.
AU - Schwarzburg, S.
AU - Schwemmer, S.
AU - Sheidaei, F.
AU - Skilton, J. L.
AU - Sol, H.
AU - Spengler, G.
AU - Stawarz, L.
AU - Steenkamp, R.
AU - Stegmann, C.
AU - Stinzing, F.
AU - Stycz, K.
AU - Sushch, I.
AU - Szostek, A.
AU - Tavernet, J. P.
AU - Terrier, R.
AU - Tluczykont, M.
AU - Trichard, C.
AU - Valerius, K.
AU - Van Eldik, C.
AU - Vasileiadis, G.
AU - Venter, C.
AU - Viana, A.
AU - Vincent, P.
AU - Völk, H. J.
AU - Volpe, F.
AU - Vorobiov, S.
AU - Vorster, M.
AU - Wagner, S. J.
AU - Ward, M.
AU - White, R.
AU - Wierzcholska, A.
AU - Wouters, D.
AU - Zacharias, M.
AU - Zajczyk, A.
AU - Zdziarski, A. A.
AU - Zech, A.
AU - Zechlin, H. S.
AU - Pelat, D.
N1 - Funding Information: The support of the Namibian authorities and of the University of Namibia in facilitating the construction and operation of H.E.S.S. is gratefully acknowledged, as is the support by the German Ministry for Education and Research (BMBF), the Max Planck Society, the German Research Foundation (DFG), the French Ministry for Research, the CNRS-IN2P3 and the Astroparticle Interdisciplinary Programme of the CNRS, the UK Science and Technology Facilities Council (STFC), the IPNP of the Charles University, the Czech Science Foundation, the Polish Ministry of Science and Higher Education, the South African Department of Science and Technology and National Research Foundation, and by the University of Namibia. We appreciate the excellent work of the technical support staff in Berlin, Durham, Hamburg, Heidelberg, Palaiseau, Paris, Saclay, and in Namibia in the construction and operation of the equipment. This research made use of the NASA/IPAC Extragalactic Database (NED) and of the SIMBAD Astronomical Database. The authors thank the RXTE team for their prompt response to our ToO request and the professional interactions that followed. The authors acknowledge the use of the publicly available Swift data, as well as the public HEASARC software packages. The authors wish to thank H. Landt and M. Véron-Cetty for very helpful discussions on the available redshift estimates of the source.
N2 - Very high-energy γ-ray emission from PKS 0447-439 was detected with the H.E.S.S. Cherenkov telescope array in December 2009. This blazar is one of the brightest extragalactic objects in the Fermi bright source list and has a hard spectrum in the MeV to GeV range. In the TeV range, a photon index of 3.89 ± 0.37 (stat) ±0.22 (sys) and a flux normalisation at 1 TeV, Φ1 TeV = (3.5 ± 1.1(stat) ± 0.9(sys)) × 10-13 cm-2 s-1 TeV-1 were found. The detection with H.E.S.S. triggered observations in the X-ray band with the Swift and RXTE telescopes. Simultaneous UV and optical data from Swift UVOT and data from the optical telescopes ATOM and ROTSE are also available. The spectrum and light curve measured with H.E.S.S. are presented and compared to the multi-wavelength data at lower energies. A rapid flare is seen in the Swift XRT and RXTE data, together with a flux variation in the UV band, at a time scale of the order of one day. A firm upper limit of z < 0.59 on the redshift of PKS 0447-439 is derived from the combined Fermi-LAT and H.E.S.S. data, given the assumptions that there is no upturn in the intrinsic spectrum above the Fermi-LAT energy range and that absorption on the extragalactic background light (EBL) is not weaker than the lower limit provided by current models. The spectral energy distribution is well described by a simple one-zone synchrotron self-Compton scenario, if the redshift of the source is less than z ≠0.4.
AB - Very high-energy γ-ray emission from PKS 0447-439 was detected with the H.E.S.S. Cherenkov telescope array in December 2009. This blazar is one of the brightest extragalactic objects in the Fermi bright source list and has a hard spectrum in the MeV to GeV range. In the TeV range, a photon index of 3.89 ± 0.37 (stat) ±0.22 (sys) and a flux normalisation at 1 TeV, Φ1 TeV = (3.5 ± 1.1(stat) ± 0.9(sys)) × 10-13 cm-2 s-1 TeV-1 were found. The detection with H.E.S.S. triggered observations in the X-ray band with the Swift and RXTE telescopes. Simultaneous UV and optical data from Swift UVOT and data from the optical telescopes ATOM and ROTSE are also available. The spectrum and light curve measured with H.E.S.S. are presented and compared to the multi-wavelength data at lower energies. A rapid flare is seen in the Swift XRT and RXTE data, together with a flux variation in the UV band, at a time scale of the order of one day. A firm upper limit of z < 0.59 on the redshift of PKS 0447-439 is derived from the combined Fermi-LAT and H.E.S.S. data, given the assumptions that there is no upturn in the intrinsic spectrum above the Fermi-LAT energy range and that absorption on the extragalactic background light (EBL) is not weaker than the lower limit provided by current models. The spectral energy distribution is well described by a simple one-zone synchrotron self-Compton scenario, if the redshift of the source is less than z ≠0.4.
KW - BL Lacertae objects: individual: PKS 0447-439
KW - Galaxies: active
KW - Gamma rays: galaxies
KW - Radiation mechanisms: non-thermal
U2 - 10.1051/0004-6361/201321108
DO - 10.1051/0004-6361/201321108
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A118