Institute: MPI für Physik     Collection: YB 2016     Display Documents

ID: 716044.0, MPI für Physik / YB 2016
Deep Broadband Observations of the Distant Gamma-ray Blazar PKS 1424+240
Authors:
Audience:Not Specified
Intended Educational Use:No
Abstract / Description:We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of $z\\ge0.6035$, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hours of VERITAS observations from three years, a multiwavelength light curve and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1$\\pm0.3$)$\\times10^{-7}$ ph m$^{-2}$s$^{-1}$ above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02$\\pm0.08$)$\\times10^{-7}$ ph m$^{-2}$s$^{-1}$ above 120 GeV. The measured differential very high energy (VHE; $E\\ge100$ GeV) spectral indices are $\\Gamma=$3.8$\\pm$0.3, 4.3$\\pm$0.6 and 4.5$\\pm$0.2 in 2009, 2011 and 2013, respectively. No significant spectral change across the observation epochs is detected. We find no evidence for variability at gamma-ray opacities of greater than $\\tau=2$, where it is postulated that any variability would be small and occur on longer than year timescales if hadronic cosmic-ray interactions with extragalactic photon fields provide a secondary VHE photon flux. The data cannot rule out such variability due to low statistics.
Classification / Thesaurus:Fermi
Comment of the Author/Creator:ApJL accepted March 17, 2014
Document Type:Article
Communicated by:MPI für Physik
Affiliations:
Identifiers:
 Full Text: You have privileges to view the following file(s): arxiv:1403.4308.pdf   Uploading file not finished...
 The scope and number of records on eDoc is subject to the collection policies defined by each institute - see "info" button in the collection browse view.