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, Tülün
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.
The VERITAS collaboration reports the detection of very-high-energy gamma-ray emission from the high-frequency-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 (10.4 sigma) 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 similar to 160 GeV and similar to 1.8 TeV is well described by a power law with an index of Gamma = 3.08 +/- 0.34(stat) +/- 0.2(sys). The integral flux is Phi (E > 200 GeV) = (12.2 +/- 2.6) x 10(-12) cm(-2) s(-1), which corresponds to similar 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 Gamma = 2.32 +/- 0.37(stat). 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 Gamma = 1.86 +/- 0.37(stat).


VERITAS discovery of > 200 GeV gamma-ray emission from the intermediate-frequency-peaked BL Lacertae object W Comae
Acciari, V. A.; et. al. (IOP Publishing, 2008-09-10)
We report the detection of very high energy gamma- ray emission from the intermediate- frequency- peaked BL Lacertae object W Comae (z = 0.102) by VERITAS. The source was observed between 2008 January and April. A strong outburst of gamma-ray emission was measured in the middle of March, lasting for only 4 days. The energy spectrum measured during the two highest flare nights is fit by a power law and is found to be very steep, with a differential photon spectral index of Gamma = 3.81 +/- 0.35(stat) +/- 0.3...
Frequency-resolved spectroscopy of XB1323-619 using XMM-Newton data: detection of a reflection region in the disc
Balman, Şölen (Oxford University Press (OUP), 2010-09-21)
We present the frequency-resolved energy spectra (FRS) of the low-mass X-ray binary dipper XB1323-619 during persistent emission in four different frequency bands using an archival XMM-Newton observation. FRS method helps to probe the inner zones of an accretion disc. XB1323-619 is an Atoll source and a type-I burster. We find that the FRS is well described by a single blackbody component with kT in a range 1.0-1.4 keV responsible for the source variability in the frequency ranges of 0.002-0.04 and 0.07-0.3...
Very high energy gamma rays from the composite SNR G0.9+0.1
Aharonian, F; et. al. (EDP Sciences, 2005-03-01)
Very high energy (> 100 GeV) gamma-ray emission has been detected for the first time from the composite supernova remnant G0.9+ 0.1 using the HESS instrument. The source is detected with a significance of approximate to 13sigma, and a photon flux above 200 GeV of ( 5.7 +/- 0.7(stat) +/- 1.2(sys)) x 10(-12) cm(-2) s(-1), making it one of the weakest sources ever detected at TeV energies. The photon spectrum is compatible with a power law ( dN/dE proportional to E-Gamma) with photon index Gamma = 2.40 +/- 0.1...
Optical imaging and spectroscopic observation of the galactic supernova remnant G85.9-0.6
GÖK, FATMA; Sezer, A.; Aktekin, E.; Guever, T.; Ercan, N. (Springer Science and Business Media LLC, 2009-11-01)
Optical CCD imaging with H alpha and [SII] filters and spectroscopic observations of the galactic supernova remnant G85.9-0.6 have been performed for the first time. The CCD image data are taken with the 1.5 m Russian-Turkish Telescope (RTT150) at TBA degrees TAK National Observatory (TUG) and spectral data are taken with the Bok 2.3 m telescope on Kitt Peak, AZ.
RXTE and Swift Observations of SWIFT J0513.4-6547
Sahiner, S.; Serim, Muhammed Miraç; Baykal, Altan; İNAM, SITKI ÇAĞDAŞ (Oxford University Press (OUP), 2016-02-11)
We present timing and spectral analysis of Swift-XRT (X-ray Telescope) and RXTE-PCA (Rossi X-ray Timing Explorer-proportional Counter Array) observations of the transient Be/X-ray pulsar SWIFT J0513.4-6547 during its outburst in 2009 and its rebrightening in 2014. From 2009 observations, short-term spin-up rate of the source after the peak of the outburst is found to have about half of the value measured at the peak of the outburst by Coe et al. When the source is quiescent between 2009 and 2014, average sp...
Citation Formats
V. A. Acciari et al., “VERITAS OBSERVATIONS OF THE BL LAC OBJECT 1ES 1218+304,” ASTROPHYSICAL JOURNAL, pp. 1370–1375, 2009, Accessed: 00, 2020. [Online]. Available: