Veritas observations of the BL Lac object 1ES 1218+304

V. A. Acciari, E. Aliu, T. Arlen, M. Beilicke, W. Benbow, S. M. Bradbury, J. H. Buckley, V. Bugaev, Y. Butt, K. L. Byrum, O. Celik, A. Cesarini, L. Ciupik, Y. C.K. Chow, P. Cogan, P. Colin, W. Cui, M. K. Daniel, T. Ergin, A. D. FalconeS. J. Fegan, J. P. Finley, P. Fortin, L. F. Fortson, A. Furniss, G. H. Gillanders, J. Grube, R. Guenette, G. Gyuk, D. Hanna, E. Hays, J. Holder, D. Horan, C. M. Hui, T. B. Humensky, A. Imran, P. Kaaret, N. Karlsson, M. Kertzman, D. B. Kieda, J. Kildea, A. Konopelko, H. Krawczynski, F. Krennrich, M. J. Lang, S. LeBohec, G. Maier, A. McCann, M. McCutcheon, P. Moriarty, R. Mukherjee, T. Nagai, J. Niemiec, R. A. Ong, D. Pandel, J. S. Perkins, M. Pohl, J. Quinn, K. Ragan, L. C. Reyes, P. T. Reynolds, H. J. Rose, M. Schroedter, G. H. Sembroski, A. W. Smith, D. Steele, S. P. Swordy, J. A. Toner, L. Valcarcel, V. V. Vassiliev, R. Wagner, S. P. Wakely, J. E. Ward, T. C. Weekes, A. Weinstein, R. J. White, D. A. Williams, S. A. Wissel, M. Wood, B. Zitzer

Research output: Contribution to journalArticle

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Abstract

The VERITAS collaboration reports the detection of very-high-energy gamma-ray emission from the highfrequency-peaked BL Lac object 1ES 1218+304 located at a redshift of z = 0.182. A gamma-ray signal was detected with a statistical significance of 10.4 standard deviations (10.4σ) for the observations taken during the first three months of 2007, confirming the discovery of this object made by the MAGIC collaboration. The photon spectrum between ∼ 160 GeV and ∼ 1.8 TeV is well described by a power law with an index of Γ = 3.08 ± 0.34stat ± 0.2sys. The integral flux is Φ (E > 200 GeV) = (12.2 ± 2.6) × 10-12 cm-2 s-1, which corresponds to ∼ 6% of that of the Crab Nebula. The light curve does not show any evidence for very high energy flux variability. Using lower limits on the density of the extragalactic background light in the near to mid-infrared, we are able to limit the range of intrinsic energy spectra for 1ES 1218+304. We show that the intrinsic photon spectrum has an index that is harder than Γ = 2.32 ± 0.37stat. When including constraints from the spectra of 1ES 1101-232 and 1ES 0229+200, the spectrum of 1ES 1218+304 is likely to be harder than Γ = 1.86 ± 0.37stat.

Original languageEnglish (US)
Pages (from-to)1370-1375
Number of pages6
JournalAstrophysical Journal
Volume695
Issue number2
DOIs
StatePublished - Apr 20 2009

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gamma rays
Crab nebula
photons
light curve
standard deviation
energy flux
energy spectra
energy
crab
power law
index
detection

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Acciari, V. A., Aliu, E., Arlen, T., Beilicke, M., Benbow, W., Bradbury, S. M., ... Zitzer, B. (2009). Veritas observations of the BL Lac object 1ES 1218+304. Astrophysical Journal, 695(2), 1370-1375. https://doi.org/10.1088/0004-637X/695/2/1370
Acciari, V. A. ; Aliu, E. ; Arlen, T. ; Beilicke, M. ; Benbow, W. ; Bradbury, S. M. ; Buckley, J. H. ; Bugaev, V. ; Butt, Y. ; Byrum, K. L. ; Celik, O. ; Cesarini, A. ; Ciupik, L. ; Chow, Y. C.K. ; Cogan, P. ; Colin, P. ; Cui, W. ; Daniel, M. K. ; Ergin, T. ; Falcone, A. D. ; Fegan, S. J. ; Finley, J. P. ; Fortin, P. ; Fortson, L. F. ; Furniss, A. ; Gillanders, G. H. ; Grube, J. ; Guenette, R. ; Gyuk, G. ; Hanna, D. ; Hays, E. ; Holder, J. ; Horan, D. ; Hui, C. M. ; Humensky, T. B. ; Imran, A. ; Kaaret, P. ; Karlsson, N. ; Kertzman, M. ; Kieda, D. B. ; Kildea, J. ; Konopelko, A. ; Krawczynski, H. ; Krennrich, F. ; Lang, M. J. ; LeBohec, S. ; Maier, G. ; McCann, A. ; McCutcheon, M. ; Moriarty, P. ; Mukherjee, R. ; Nagai, T. ; Niemiec, J. ; Ong, R. A. ; Pandel, D. ; Perkins, J. S. ; Pohl, M. ; Quinn, J. ; Ragan, K. ; Reyes, L. C. ; Reynolds, P. T. ; Rose, H. J. ; Schroedter, M. ; Sembroski, G. H. ; Smith, A. W. ; Steele, D. ; Swordy, S. P. ; Toner, J. A. ; Valcarcel, L. ; Vassiliev, V. V. ; Wagner, R. ; Wakely, S. P. ; Ward, J. E. ; Weekes, T. C. ; Weinstein, A. ; White, R. J. ; Williams, D. A. ; Wissel, S. A. ; Wood, M. ; Zitzer, B. / Veritas observations of the BL Lac object 1ES 1218+304. In: Astrophysical Journal. 2009 ; Vol. 695, No. 2. pp. 1370-1375.
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abstract = "The VERITAS collaboration reports the detection of very-high-energy gamma-ray emission from the highfrequency-peaked BL Lac object 1ES 1218+304 located at a redshift of z = 0.182. A gamma-ray signal was detected with a statistical significance of 10.4 standard deviations (10.4σ) for the observations taken during the first three months of 2007, confirming the discovery of this object made by the MAGIC collaboration. The photon spectrum between ∼ 160 GeV and ∼ 1.8 TeV is well described by a power law with an index of Γ = 3.08 ± 0.34stat ± 0.2sys. The integral flux is Φ (E > 200 GeV) = (12.2 ± 2.6) × 10-12 cm-2 s-1, which corresponds to ∼ 6{\%} of that of the Crab Nebula. The light curve does not show any evidence for very high energy flux variability. Using lower limits on the density of the extragalactic background light in the near to mid-infrared, we are able to limit the range of intrinsic energy spectra for 1ES 1218+304. We show that the intrinsic photon spectrum has an index that is harder than Γ = 2.32 ± 0.37stat. When including constraints from the spectra of 1ES 1101-232 and 1ES 0229+200, the spectrum of 1ES 1218+304 is likely to be harder than Γ = 1.86 ± 0.37stat.",
author = "Acciari, {V. A.} and E. Aliu and T. Arlen and M. Beilicke and W. Benbow and Bradbury, {S. M.} and Buckley, {J. H.} and V. Bugaev and Y. Butt and Byrum, {K. L.} and O. Celik and A. Cesarini and L. Ciupik and Chow, {Y. C.K.} and P. Cogan and P. Colin and W. Cui and Daniel, {M. K.} and T. Ergin and Falcone, {A. D.} and Fegan, {S. J.} and Finley, {J. P.} and P. Fortin and Fortson, {L. F.} and A. Furniss and Gillanders, {G. H.} and J. Grube and R. Guenette and G. Gyuk and D. Hanna and E. Hays and J. Holder and D. Horan and Hui, {C. M.} and Humensky, {T. B.} and A. Imran and P. Kaaret and N. Karlsson and M. Kertzman and Kieda, {D. B.} and J. Kildea and A. Konopelko and H. Krawczynski and F. Krennrich and Lang, {M. J.} and S. LeBohec and G. Maier and A. McCann and M. McCutcheon and P. Moriarty and R. Mukherjee and T. Nagai and J. Niemiec and Ong, {R. A.} and D. Pandel and Perkins, {J. S.} and M. Pohl and J. Quinn and K. Ragan and Reyes, {L. C.} and Reynolds, {P. T.} and Rose, {H. J.} and M. Schroedter and Sembroski, {G. H.} and Smith, {A. W.} and D. Steele and Swordy, {S. P.} and Toner, {J. A.} and L. Valcarcel and Vassiliev, {V. V.} and R. Wagner and Wakely, {S. P.} and Ward, {J. E.} and Weekes, {T. C.} and A. Weinstein and White, {R. J.} and Williams, {D. A.} and Wissel, {S. A.} and M. Wood and B. Zitzer",
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Acciari, VA, Aliu, E, Arlen, T, Beilicke, M, Benbow, W, Bradbury, SM, Buckley, JH, Bugaev, V, Butt, Y, Byrum, KL, Celik, O, Cesarini, A, Ciupik, L, Chow, YCK, Cogan, P, Colin, P, Cui, W, Daniel, MK, Ergin, T, Falcone, AD, Fegan, SJ, Finley, JP, Fortin, P, Fortson, LF, Furniss, A, Gillanders, GH, Grube, J, Guenette, R, Gyuk, G, Hanna, D, Hays, E, Holder, J, Horan, D, Hui, CM, Humensky, TB, Imran, A, Kaaret, P, Karlsson, N, Kertzman, M, Kieda, DB, Kildea, J, Konopelko, A, Krawczynski, H, Krennrich, F, Lang, MJ, LeBohec, S, Maier, G, McCann, A, McCutcheon, M, Moriarty, P, Mukherjee, R, Nagai, T, Niemiec, J, Ong, RA, Pandel, D, Perkins, JS, Pohl, M, Quinn, J, Ragan, K, Reyes, LC, Reynolds, PT, Rose, HJ, Schroedter, M, Sembroski, GH, Smith, AW, Steele, D, Swordy, SP, Toner, JA, Valcarcel, L, Vassiliev, VV, Wagner, R, Wakely, SP, Ward, JE, Weekes, TC, Weinstein, A, White, RJ, Williams, DA, Wissel, SA, Wood, M & Zitzer, B 2009, 'Veritas observations of the BL Lac object 1ES 1218+304', Astrophysical Journal, vol. 695, no. 2, pp. 1370-1375. https://doi.org/10.1088/0004-637X/695/2/1370

Veritas observations of the BL Lac object 1ES 1218+304. / Acciari, V. A.; Aliu, E.; Arlen, T.; Beilicke, M.; Benbow, W.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.; Butt, Y.; Byrum, K. L.; Celik, O.; Cesarini, A.; Ciupik, L.; Chow, Y. C.K.; Cogan, P.; Colin, P.; Cui, W.; Daniel, M. K.; Ergin, T.; Falcone, A. D.; Fegan, S. J.; Finley, J. P.; Fortin, P.; Fortson, L. F.; Furniss, A.; Gillanders, G. H.; Grube, J.; Guenette, R.; Gyuk, G.; Hanna, D.; Hays, E.; Holder, J.; Horan, D.; Hui, C. M.; Humensky, T. B.; Imran, A.; Kaaret, P.; Karlsson, N.; Kertzman, M.; Kieda, D. B.; Kildea, J.; Konopelko, A.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Maier, G.; McCann, A.; McCutcheon, M.; Moriarty, P.; Mukherjee, R.; Nagai, T.; Niemiec, J.; Ong, R. A.; Pandel, D.; Perkins, J. S.; Pohl, M.; Quinn, J.; Ragan, K.; Reyes, L. C.; Reynolds, P. T.; Rose, H. J.; Schroedter, M.; Sembroski, G. H.; Smith, A. W.; Steele, D.; Swordy, S. P.; Toner, J. A.; Valcarcel, L.; Vassiliev, V. V.; Wagner, R.; Wakely, S. P.; Ward, J. E.; Weekes, T. C.; Weinstein, A.; White, R. J.; Williams, D. A.; Wissel, S. A.; Wood, M.; Zitzer, B.

In: Astrophysical Journal, Vol. 695, No. 2, 20.04.2009, p. 1370-1375.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Veritas observations of the BL Lac object 1ES 1218+304

AU - Acciari, V. A.

AU - Aliu, E.

AU - Arlen, T.

AU - Beilicke, M.

AU - Benbow, W.

AU - Bradbury, S. M.

AU - Buckley, J. H.

AU - Bugaev, V.

AU - Butt, Y.

AU - Byrum, K. L.

AU - Celik, O.

AU - Cesarini, A.

AU - Ciupik, L.

AU - Chow, Y. C.K.

AU - Cogan, P.

AU - Colin, P.

AU - Cui, W.

AU - Daniel, M. K.

AU - Ergin, T.

AU - Falcone, A. D.

AU - Fegan, S. J.

AU - Finley, J. P.

AU - Fortin, P.

AU - Fortson, L. F.

AU - Furniss, A.

AU - Gillanders, G. H.

AU - Grube, J.

AU - Guenette, R.

AU - Gyuk, G.

AU - Hanna, D.

AU - Hays, E.

AU - Holder, J.

AU - Horan, D.

AU - Hui, C. M.

AU - Humensky, T. B.

AU - Imran, A.

AU - Kaaret, P.

AU - Karlsson, N.

AU - Kertzman, M.

AU - Kieda, D. B.

AU - Kildea, J.

AU - Konopelko, A.

AU - Krawczynski, H.

AU - Krennrich, F.

AU - Lang, M. J.

AU - LeBohec, S.

AU - Maier, G.

AU - McCann, A.

AU - McCutcheon, M.

AU - Moriarty, P.

AU - Mukherjee, R.

AU - Nagai, T.

AU - Niemiec, J.

AU - Ong, R. A.

AU - Pandel, D.

AU - Perkins, J. S.

AU - Pohl, M.

AU - Quinn, J.

AU - Ragan, K.

AU - Reyes, L. C.

AU - Reynolds, P. T.

AU - Rose, H. J.

AU - Schroedter, M.

AU - Sembroski, G. H.

AU - Smith, A. W.

AU - Steele, D.

AU - Swordy, S. P.

AU - Toner, J. A.

AU - Valcarcel, L.

AU - Vassiliev, V. V.

AU - Wagner, R.

AU - Wakely, S. P.

AU - Ward, J. E.

AU - Weekes, T. C.

AU - Weinstein, A.

AU - White, R. J.

AU - Williams, D. A.

AU - Wissel, S. A.

AU - Wood, M.

AU - Zitzer, B.

PY - 2009/4/20

Y1 - 2009/4/20

N2 - The VERITAS collaboration reports the detection of very-high-energy gamma-ray emission from the highfrequency-peaked BL Lac object 1ES 1218+304 located at a redshift of z = 0.182. A gamma-ray signal was detected with a statistical significance of 10.4 standard deviations (10.4σ) for the observations taken during the first three months of 2007, confirming the discovery of this object made by the MAGIC collaboration. The photon spectrum between ∼ 160 GeV and ∼ 1.8 TeV is well described by a power law with an index of Γ = 3.08 ± 0.34stat ± 0.2sys. The integral flux is Φ (E > 200 GeV) = (12.2 ± 2.6) × 10-12 cm-2 s-1, which corresponds to ∼ 6% of that of the Crab Nebula. The light curve does not show any evidence for very high energy flux variability. Using lower limits on the density of the extragalactic background light in the near to mid-infrared, we are able to limit the range of intrinsic energy spectra for 1ES 1218+304. We show that the intrinsic photon spectrum has an index that is harder than Γ = 2.32 ± 0.37stat. When including constraints from the spectra of 1ES 1101-232 and 1ES 0229+200, the spectrum of 1ES 1218+304 is likely to be harder than Γ = 1.86 ± 0.37stat.

AB - The VERITAS collaboration reports the detection of very-high-energy gamma-ray emission from the highfrequency-peaked BL Lac object 1ES 1218+304 located at a redshift of z = 0.182. A gamma-ray signal was detected with a statistical significance of 10.4 standard deviations (10.4σ) for the observations taken during the first three months of 2007, confirming the discovery of this object made by the MAGIC collaboration. The photon spectrum between ∼ 160 GeV and ∼ 1.8 TeV is well described by a power law with an index of Γ = 3.08 ± 0.34stat ± 0.2sys. The integral flux is Φ (E > 200 GeV) = (12.2 ± 2.6) × 10-12 cm-2 s-1, which corresponds to ∼ 6% of that of the Crab Nebula. The light curve does not show any evidence for very high energy flux variability. Using lower limits on the density of the extragalactic background light in the near to mid-infrared, we are able to limit the range of intrinsic energy spectra for 1ES 1218+304. We show that the intrinsic photon spectrum has an index that is harder than Γ = 2.32 ± 0.37stat. When including constraints from the spectra of 1ES 1101-232 and 1ES 0229+200, the spectrum of 1ES 1218+304 is likely to be harder than Γ = 1.86 ± 0.37stat.

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Acciari VA, Aliu E, Arlen T, Beilicke M, Benbow W, Bradbury SM et al. Veritas observations of the BL Lac object 1ES 1218+304. Astrophysical Journal. 2009 Apr 20;695(2):1370-1375. https://doi.org/10.1088/0004-637X/695/2/1370