High zenith angle observations of PKS 2155-304 with the MAGIC-I telescope

J. Aleksić; E. A. Alvarez; L. A. Antonelli; P. Antoranz; M. Asensio; M. Backes; U. Barres De Almeida; J. A. Barrio; D. Bastieri; J. Becerra González; W. Bednarek; A. Berdyugin; K. Berger; E. Bernardini; A. Biland; O. Blanch; R. K. Bock; A. Boller; G. Bonnoli; D. Borla Tridon; I. Braun; T. Bretz; A. Cañellas; E. Carmona; A. Carosi; P. Colin; E. Colombo; J. L. Contreras; J. Cortina; L. Cossio; S. Covino; F. Dazzi; A. De Angelis; G. De Caneva; E. De Cea Del Pozo; B. De Lotto; C. Delgado Mendez; A. Diago Ortega; M. Doert; A. Domínguez; D. Dominis Prester; D. Dorner; M. Doro; D. Eisenacher; D. Elsaesser; D. Ferenc; M. V. Fonseca; L. Font; C. Fruck; R. J. García López; M. Garczarczyk; D. Garrido; G. Giavitto; N. Godinović; S. R. Gozzini; D. Hadasch; D. Häfner; A. Herrero; D. Hildebrand; D. Höhne-Mönch; J. Hose; D. Hrupec; T. Jogler; H. Kellermann; S. Klepser; T. Krähenbühl; J. Krause; J. Kushida; A. La Barbera; D. Lelas; E. Leonardo; N. Lewandowska; E. Lindfors; S. Lombardi; M. López; R. López; A. López-Oramas; E. Lorenz; M. Makariev; G. Maneva; N. Mankuzhiyil; K. Mannheim; L. Maraschi; B. Marcote; M. Mariotti; M. Martínez; D. Mazin; M. Meucci; J. M. Miranda; R. Mirzoyan; J. Moldón; A. Moralejo; P. Munar-Adrover; A. Niedzwiecki; D. Nieto; K. Nilsson; N. Nowak; R. Orito; S. Paiano; D. Paneque

doi:10.1051/0004-6361/201218796

High zenith angle observations of PKS 2155-304 with the MAGIC-I telescope

J. Aleksić, E. A. Alvarez, L. A. Antonelli, P. Antoranz, M. Asensio, M. Backes, U. Barres De Almeida, J. A. Barrio, D. Bastieri, J. Becerra González, W. Bednarek, A. Berdyugin, K. Berger, E. Bernardini, A. Biland, O. Blanch, R. K. Bock, A. Boller, G. Bonnoli, D. Borla TridonI. Braun, T. Bretz, A. Cañellas, E. Carmona, A. Carosi, P. Colin, E. Colombo, J. L. Contreras, J. Cortina, L. Cossio, S. Covino, F. Dazzi, A. De Angelis, G. De Caneva, E. De Cea Del Pozo, B. De Lotto, C. Delgado Mendez, A. Diago Ortega, M. Doert, A. Domínguez, D. Dominis Prester, D. Dorner, M. Doro, D. Eisenacher, D. Elsaesser, D. Ferenc, M. V. Fonseca, L. Font, C. Fruck, R. J. García López, M. Garczarczyk, D. Garrido, G. Giavitto, N. Godinović, S. R. Gozzini, D. Hadasch, D. Häfner, A. Herrero, D. Hildebrand, D. Höhne-Mönch, J. Hose, D. Hrupec, T. Jogler, H. Kellermann, S. Klepser, T. Krähenbühl, J. Krause, J. Kushida, A. La Barbera, D. Lelas, E. Leonardo, N. Lewandowska, E. Lindfors, S. Lombardi, M. López, R. López, A. López-Oramas, E. Lorenz, M. Makariev, G. Maneva, N. Mankuzhiyil, K. Mannheim, L. Maraschi, B. Marcote, M. Mariotti, M. Martínez, D. Mazin, M. Meucci, J. M. Miranda, R. Mirzoyan, J. Moldón, A. Moralejo, P. Munar-Adrover, A. Niedzwiecki, D. Nieto, K. Nilsson, N. Nowak, R. Orito, S. Paiano, D. Paneque

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

6 Citations (Scopus)

Abstract

Context. The high frequency peaked BL Lac PKS 2155-304 with a redshift of z = 0.116 was discovered in 1997 in the very high energy (VHE, E > 100 GeV) γ-ray range by the University of Durham Mark VI γ-ray Cherenkov telescope in Australia with a flux corresponding to 20% of the Crab Nebula flux. It was later observed and detected with high significance by the southern Cherenkov observatory H.E.S.S. establishing this source as the best studied southern TeV blazar. Detection from the northern hemisphere is difficult due to challenging observation conditions under large zenith angles. In July 2006, the H.E.S.S. collaboration reported an extraordinary outburst of VHE γ-emission. During the outburst, the VHE γ-ray emission was found to be variable on the time scales of minutes and with a mean flux of ∼7 times the flux observed from the Crab Nebula. Follow-up observations with the MAGIC-I standalone Cherenkov telescope were triggered by this extraordinary outburst and PKS 2155-304 was observed between 28 July to 2 August 2006 for 15 h at large zenith angles. Aims. We studied the behavior of the source after its extraordinary flare. Furthermore, we developed an analysis method in order to analyze these data taken under large zenith angles. Methods. Here we present an enhanced analysis method for data taken at high zenith angles. We developed improved methods for event selection that led to a better background suppression. Results. The quality of the results presented here is superior to the results presented previously for this data set: detection of the source on a higher significance level and a lower analysis threshold. The averaged energy spectrum we derived has a spectral index of (-3.5 ± 0.2) above 400 GeV, which is in good agreement with the spectral shape measured by H.E.S.S. during the major flare on MJD 53 944. Furthermore, we present the spectral energy distribution modeling of PKS 2155-304. With our observations we increased the duty cycle of the source extending the light curve derived by H.E.S.S. after the outburst. Finally, we find night-by-night variability with a maximal amplitude of a factor three to four and an intranight variability in one of the nights (MJD 53 945) with a similar amplitude. © 2012 ESO.

Original language	English
Article number	A75
Journal	Astronomy and Astrophysics
Volume	544
DOIs	https://doi.org/10.1051/0004-6361/201218796
Publication status	Published - 8 Aug 2012

Keywords

Astroparticle physics
BL Lacertae objects: individual: PKS 2155-304
Methods: data analysis

Access to Document

10.1051/0004-6361/201218796

Cite this

Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., Barres De Almeida, U., Barrio, J. A., Bastieri, D., Becerra González, J., Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., ... Paneque, D. (2012). High zenith angle observations of PKS 2155-304 with the MAGIC-I telescope. Astronomy and Astrophysics, 544, [A75]. https://doi.org/10.1051/0004-6361/201218796

@article{9d31c7fe746a4dccbbd7365bb7e7736d,

title = "High zenith angle observations of PKS 2155-304 with the MAGIC-I telescope",

abstract = "Context. The high frequency peaked BL Lac PKS 2155-304 with a redshift of z = 0.116 was discovered in 1997 in the very high energy (VHE, E > 100 GeV) γ-ray range by the University of Durham Mark VI γ-ray Cherenkov telescope in Australia with a flux corresponding to 20% of the Crab Nebula flux. It was later observed and detected with high significance by the southern Cherenkov observatory H.E.S.S. establishing this source as the best studied southern TeV blazar. Detection from the northern hemisphere is difficult due to challenging observation conditions under large zenith angles. In July 2006, the H.E.S.S. collaboration reported an extraordinary outburst of VHE γ-emission. During the outburst, the VHE γ-ray emission was found to be variable on the time scales of minutes and with a mean flux of ∼7 times the flux observed from the Crab Nebula. Follow-up observations with the MAGIC-I standalone Cherenkov telescope were triggered by this extraordinary outburst and PKS 2155-304 was observed between 28 July to 2 August 2006 for 15 h at large zenith angles. Aims. We studied the behavior of the source after its extraordinary flare. Furthermore, we developed an analysis method in order to analyze these data taken under large zenith angles. Methods. Here we present an enhanced analysis method for data taken at high zenith angles. We developed improved methods for event selection that led to a better background suppression. Results. The quality of the results presented here is superior to the results presented previously for this data set: detection of the source on a higher significance level and a lower analysis threshold. The averaged energy spectrum we derived has a spectral index of (-3.5 ± 0.2) above 400 GeV, which is in good agreement with the spectral shape measured by H.E.S.S. during the major flare on MJD 53 944. Furthermore, we present the spectral energy distribution modeling of PKS 2155-304. With our observations we increased the duty cycle of the source extending the light curve derived by H.E.S.S. after the outburst. Finally, we find night-by-night variability with a maximal amplitude of a factor three to four and an intranight variability in one of the nights (MJD 53 945) with a similar amplitude. {\textcopyright} 2012 ESO.",

keywords = "Astroparticle physics, BL Lacertae objects: individual: PKS 2155-304, Methods: data analysis",

author = "J. Aleksi{\'c} and Alvarez, {E. A.} and Antonelli, {L. A.} and P. Antoranz and M. Asensio and M. Backes and {Barres De Almeida}, U. and Barrio, {J. A.} and D. Bastieri and {Becerra Gonz{\'a}lez}, J. and W. Bednarek and A. Berdyugin and K. Berger and E. Bernardini and A. Biland and O. Blanch and Bock, {R. K.} and A. Boller and G. Bonnoli and {Borla Tridon}, D. and I. Braun and T. Bretz and A. Ca{\~n}ellas and E. Carmona and A. Carosi and P. Colin and E. Colombo and Contreras, {J. L.} and J. Cortina and L. Cossio and S. Covino and F. Dazzi and {De Angelis}, A. and {De Caneva}, G. and {De Cea Del Pozo}, E. and {De Lotto}, B. and {Delgado Mendez}, C. and {Diago Ortega}, A. and M. Doert and A. Dom{\'i}nguez and {Dominis Prester}, D. and D. Dorner and M. Doro and D. Eisenacher and D. Elsaesser and D. Ferenc and Fonseca, {M. V.} and L. Font and C. Fruck and {Garc{\'i}a L{\'o}pez}, {R. J.} and M. Garczarczyk and D. Garrido and G. Giavitto and N. Godinovi{\'c} and Gozzini, {S. R.} and D. Hadasch and D. H{\"a}fner and A. Herrero and D. Hildebrand and D. H{\"o}hne-M{\"o}nch and J. Hose and D. Hrupec and T. Jogler and H. Kellermann and S. Klepser and T. Kr{\"a}henb{\"u}hl and J. Krause and J. Kushida and {La Barbera}, A. and D. Lelas and E. Leonardo and N. Lewandowska and E. Lindfors and S. Lombardi and M. L{\'o}pez and R. L{\'o}pez and A. L{\'o}pez-Oramas and E. Lorenz and M. Makariev and G. Maneva and N. Mankuzhiyil and K. Mannheim and L. Maraschi and B. Marcote and M. Mariotti and M. Mart{\'i}nez and D. Mazin and M. Meucci and Miranda, {J. M.} and R. Mirzoyan and J. Mold{\'o}n and A. Moralejo and P. Munar-Adrover and A. Niedzwiecki and D. Nieto and K. Nilsson and N. Nowak and R. Orito and S. Paiano and D. Paneque",

year = "2012",

month = aug,

day = "8",

doi = "10.1051/0004-6361/201218796",

language = "English",

volume = "544",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

}

Aleksić, J, Alvarez, EA, Antonelli, LA, Antoranz, P, Asensio, M, Backes, M, Barres De Almeida, U, Barrio, JA, Bastieri, D, Becerra González, J, Bednarek, W, Berdyugin, A, Berger, K, Bernardini, E, Biland, A, Blanch, O, Bock, RK, Boller, A, Bonnoli, G, Borla Tridon, D, Braun, I, Bretz, T, Cañellas, A, Carmona, E, Carosi, A, Colin, P, Colombo, E, Contreras, JL, Cortina, J, Cossio, L, Covino, S, Dazzi, F, De Angelis, A, De Caneva, G, De Cea Del Pozo, E, De Lotto, B, Delgado Mendez, C, Diago Ortega, A, Doert, M, Domínguez, A, Dominis Prester, D, Dorner, D, Doro, M, Eisenacher, D, Elsaesser, D, Ferenc, D, Fonseca, MV, Font, L, Fruck, C, García López, RJ, Garczarczyk, M, Garrido, D, Giavitto, G, Godinović, N, Gozzini, SR, Hadasch, D, Häfner, D, Herrero, A, Hildebrand, D, Höhne-Mönch, D, Hose, J, Hrupec, D, Jogler, T, Kellermann, H, Klepser, S, Krähenbühl, T, Krause, J, Kushida, J, La Barbera, A, Lelas, D, Leonardo, E, Lewandowska, N, Lindfors, E, Lombardi, S, López, M, López, R, López-Oramas, A, Lorenz, E, Makariev, M, Maneva, G, Mankuzhiyil, N, Mannheim, K, Maraschi, L, Marcote, B, Mariotti, M, Martínez, M, Mazin, D, Meucci, M, Miranda, JM, Mirzoyan, R, Moldón, J, Moralejo, A, Munar-Adrover, P, Niedzwiecki, A, Nieto, D, Nilsson, K, Nowak, N, Orito, R, Paiano, S & Paneque, D 2012, 'High zenith angle observations of PKS 2155-304 with the MAGIC-I telescope', Astronomy and Astrophysics, vol. 544, A75. https://doi.org/10.1051/0004-6361/201218796

TY - JOUR

T1 - High zenith angle observations of PKS 2155-304 with the MAGIC-I telescope

AU - Aleksić, J.

AU - Alvarez, E. A.

AU - Antonelli, L. A.

AU - Antoranz, P.

AU - Asensio, M.

AU - Backes, M.

AU - Barres De Almeida, U.

AU - Barrio, J. A.

AU - Bastieri, D.

AU - Becerra González, J.

AU - Bednarek, W.

AU - Berdyugin, A.

AU - Berger, K.

AU - Bernardini, E.

AU - Biland, A.

AU - Blanch, O.

AU - Bock, R. K.

AU - Boller, A.

AU - Bonnoli, G.

AU - Borla Tridon, D.

AU - Braun, I.

AU - Bretz, T.

AU - Cañellas, A.

AU - Carmona, E.

AU - Carosi, A.

AU - Colin, P.

AU - Colombo, E.

AU - Contreras, J. L.

AU - Cortina, J.

AU - Cossio, L.

AU - Covino, S.

AU - Dazzi, F.

AU - De Angelis, A.

AU - De Caneva, G.

AU - De Cea Del Pozo, E.

AU - De Lotto, B.

AU - Delgado Mendez, C.

AU - Diago Ortega, A.

AU - Doert, M.

AU - Domínguez, A.

AU - Dominis Prester, D.

AU - Dorner, D.

AU - Doro, M.

AU - Eisenacher, D.

AU - Elsaesser, D.

AU - Ferenc, D.

AU - Fonseca, M. V.

AU - Font, L.

AU - Fruck, C.

AU - García López, R. J.

AU - Garczarczyk, M.

AU - Garrido, D.

AU - Giavitto, G.

AU - Godinović, N.

AU - Gozzini, S. R.

AU - Hadasch, D.

AU - Häfner, D.

AU - Herrero, A.

AU - Hildebrand, D.

AU - Höhne-Mönch, D.

AU - Hose, J.

AU - Hrupec, D.

AU - Jogler, T.

AU - Kellermann, H.

AU - Klepser, S.

AU - Krähenbühl, T.

AU - Krause, J.

AU - Kushida, J.

AU - La Barbera, A.

AU - Lelas, D.

AU - Leonardo, E.

AU - Lewandowska, N.

AU - Lindfors, E.

AU - Lombardi, S.

AU - López, M.

AU - López, R.

AU - López-Oramas, A.

AU - Lorenz, E.

AU - Makariev, M.

AU - Maneva, G.

AU - Mankuzhiyil, N.

AU - Mannheim, K.

AU - Maraschi, L.

AU - Marcote, B.

AU - Mariotti, M.

AU - Martínez, M.

AU - Mazin, D.

AU - Meucci, M.

AU - Miranda, J. M.

AU - Mirzoyan, R.

AU - Moldón, J.

AU - Moralejo, A.

AU - Munar-Adrover, P.

AU - Niedzwiecki, A.

AU - Nieto, D.

AU - Nilsson, K.

AU - Nowak, N.

AU - Orito, R.

AU - Paiano, S.

AU - Paneque, D.

PY - 2012/8/8

Y1 - 2012/8/8

N2 - Context. The high frequency peaked BL Lac PKS 2155-304 with a redshift of z = 0.116 was discovered in 1997 in the very high energy (VHE, E > 100 GeV) γ-ray range by the University of Durham Mark VI γ-ray Cherenkov telescope in Australia with a flux corresponding to 20% of the Crab Nebula flux. It was later observed and detected with high significance by the southern Cherenkov observatory H.E.S.S. establishing this source as the best studied southern TeV blazar. Detection from the northern hemisphere is difficult due to challenging observation conditions under large zenith angles. In July 2006, the H.E.S.S. collaboration reported an extraordinary outburst of VHE γ-emission. During the outburst, the VHE γ-ray emission was found to be variable on the time scales of minutes and with a mean flux of ∼7 times the flux observed from the Crab Nebula. Follow-up observations with the MAGIC-I standalone Cherenkov telescope were triggered by this extraordinary outburst and PKS 2155-304 was observed between 28 July to 2 August 2006 for 15 h at large zenith angles. Aims. We studied the behavior of the source after its extraordinary flare. Furthermore, we developed an analysis method in order to analyze these data taken under large zenith angles. Methods. Here we present an enhanced analysis method for data taken at high zenith angles. We developed improved methods for event selection that led to a better background suppression. Results. The quality of the results presented here is superior to the results presented previously for this data set: detection of the source on a higher significance level and a lower analysis threshold. The averaged energy spectrum we derived has a spectral index of (-3.5 ± 0.2) above 400 GeV, which is in good agreement with the spectral shape measured by H.E.S.S. during the major flare on MJD 53 944. Furthermore, we present the spectral energy distribution modeling of PKS 2155-304. With our observations we increased the duty cycle of the source extending the light curve derived by H.E.S.S. after the outburst. Finally, we find night-by-night variability with a maximal amplitude of a factor three to four and an intranight variability in one of the nights (MJD 53 945) with a similar amplitude. © 2012 ESO.

AB - Context. The high frequency peaked BL Lac PKS 2155-304 with a redshift of z = 0.116 was discovered in 1997 in the very high energy (VHE, E > 100 GeV) γ-ray range by the University of Durham Mark VI γ-ray Cherenkov telescope in Australia with a flux corresponding to 20% of the Crab Nebula flux. It was later observed and detected with high significance by the southern Cherenkov observatory H.E.S.S. establishing this source as the best studied southern TeV blazar. Detection from the northern hemisphere is difficult due to challenging observation conditions under large zenith angles. In July 2006, the H.E.S.S. collaboration reported an extraordinary outburst of VHE γ-emission. During the outburst, the VHE γ-ray emission was found to be variable on the time scales of minutes and with a mean flux of ∼7 times the flux observed from the Crab Nebula. Follow-up observations with the MAGIC-I standalone Cherenkov telescope were triggered by this extraordinary outburst and PKS 2155-304 was observed between 28 July to 2 August 2006 for 15 h at large zenith angles. Aims. We studied the behavior of the source after its extraordinary flare. Furthermore, we developed an analysis method in order to analyze these data taken under large zenith angles. Methods. Here we present an enhanced analysis method for data taken at high zenith angles. We developed improved methods for event selection that led to a better background suppression. Results. The quality of the results presented here is superior to the results presented previously for this data set: detection of the source on a higher significance level and a lower analysis threshold. The averaged energy spectrum we derived has a spectral index of (-3.5 ± 0.2) above 400 GeV, which is in good agreement with the spectral shape measured by H.E.S.S. during the major flare on MJD 53 944. Furthermore, we present the spectral energy distribution modeling of PKS 2155-304. With our observations we increased the duty cycle of the source extending the light curve derived by H.E.S.S. after the outburst. Finally, we find night-by-night variability with a maximal amplitude of a factor three to four and an intranight variability in one of the nights (MJD 53 945) with a similar amplitude. © 2012 ESO.

KW - Astroparticle physics

KW - BL Lacertae objects: individual: PKS 2155-304

KW - Methods: data analysis

U2 - 10.1051/0004-6361/201218796

DO - 10.1051/0004-6361/201218796

M3 - Article

SN - 0004-6361

VL - 544

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

M1 - A75

ER -

High zenith angle observations of PKS 2155-304 with the MAGIC-I telescope

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Keywords

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