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Title: Discovery of Very High Energy Gamma Rays from PKS 1424+240 and Multiwavelength Constraints on its Redshift

Abstract

We report the first detection of very-high-energy (VHE) gamma-ray emission above 140GeV from PKS 1424+240, a BL Lac object with an unknown redshift. The photon spectrum above 140GeV measured by VERITAS is well described by a power law with a photon index of 3.8 {+-}0.5{sub stat} {+-} 0.3{sub syst} and a flux normalization at 200 GeV of (5.1 {+-} 0.9{sub stat} {+-} 0.5{sub syst}) x 10{sup -11} TeV{sup -1} cm{sup -2} s{sup -1}, where stat and syst denote the statistical and systematical uncertainty, respectively. The VHE flux is steady over the observation period between MJD 54881 and 55003 (2009 February 19 to June 21). Flux variability is also not observed in contemporaneous high energy observations with the Fermi Large Area Telescope (LAT). Contemporaneous X-ray and optical data were also obtained from the Swift XRT and MDM observatory, respectively. The broadband spectral energy distribution (SED) is well described by a one-zone synchrotron self-Compton (SSC) model favoring a redshift of less than 0.1. Using the photon index measured with Fermi in combination with recent extragalactic background light (EBL) absorption models it can be concluded from the VERITAS data that the redshift of PKS 1424+240 is less than 0.66.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1046386
Report Number(s):
SLAC-PUB-14913
arXiv:0912.0730; TRN: US1203817
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; DETECTION; ENERGY SPECTRA; LINEAR ABSORPTION MODELS; PHOTONS; SUPERCONDUCTING SUPER COLLIDER; SYNCHROTRONS; TELESCOPES; Astrophysics,ASTRO

Citation Formats

Acciari, V A, /Harvard-Smithsonian Ctr. Astrophys., Aliu, E, /Delaware U., Bartol Inst., Arlen, T, /UCLA, Aune, T, /UC, Santa Cruz, Bautista, M, /McGill U., Beilicke, M. /Washington U., St. Louis, Benbow, W, /Harvard-Smithsonian Ctr. Astrophys., Bottcher, M, /Ohio U., Boltuch, D, /Delaware U., Bartol Inst., Bradbury, S M, /Leeds U., Buckley, J H, /Washington U., St. Louis, Bugaev, V, /Washington U., St. Louis, Byrum, K, /Argonne, Cannon, A, /University Coll., Dublin, Cesarini, A, /Natl. U. of Ireland, Galway, Chow, Y C, /UCLA, Ciupik, L, /Roosevelt U., Chicago, Cogan, P, /McGill U., Cui, W, /Purdue U., Duke, C, /Grinnell Coll., Falcone, A, /Penn State U. /Purdue U. /Utah U. /Roosevelt U., Chicago /Harvard-Smithsonian Ctr. Astrophys. /Purdue U. /Natl. U. of Ireland, Galway /Utah U. /University Coll., Dublin /McGill U. /Roosevelt U., Chicago /McGill U. /Delaware U., Bartol Inst. /Utah U. /Chicago U., EFI /Iowa State U. /Roosevelt U., Chicago /DePauw U. /Utah U. /Pittsburg State U. /Washington U., St. Louis /Iowa State U. /Natl. U. of Ireland, Galway /Utah U. /McGill U. /Washington U., St. Louis /McGill U. /McGill U. /Purdue U. /Anderson U. /Galway-Mayo Inst. of Tech. /Iowa State U. /UCLA, and /more authors. Discovery of Very High Energy Gamma Rays from PKS 1424+240 and Multiwavelength Constraints on its Redshift. United States: N. p., 2012. Web. doi:10.2172/1046386.
Acciari, V A, /Harvard-Smithsonian Ctr. Astrophys., Aliu, E, /Delaware U., Bartol Inst., Arlen, T, /UCLA, Aune, T, /UC, Santa Cruz, Bautista, M, /McGill U., Beilicke, M. /Washington U., St. Louis, Benbow, W, /Harvard-Smithsonian Ctr. Astrophys., Bottcher, M, /Ohio U., Boltuch, D, /Delaware U., Bartol Inst., Bradbury, S M, /Leeds U., Buckley, J H, /Washington U., St. Louis, Bugaev, V, /Washington U., St. Louis, Byrum, K, /Argonne, Cannon, A, /University Coll., Dublin, Cesarini, A, /Natl. U. of Ireland, Galway, Chow, Y C, /UCLA, Ciupik, L, /Roosevelt U., Chicago, Cogan, P, /McGill U., Cui, W, /Purdue U., Duke, C, /Grinnell Coll., Falcone, A, /Penn State U. /Purdue U. /Utah U. /Roosevelt U., Chicago /Harvard-Smithsonian Ctr. Astrophys. /Purdue U. /Natl. U. of Ireland, Galway /Utah U. /University Coll., Dublin /McGill U. /Roosevelt U., Chicago /McGill U. /Delaware U., Bartol Inst. /Utah U. /Chicago U., EFI /Iowa State U. /Roosevelt U., Chicago /DePauw U. /Utah U. /Pittsburg State U. /Washington U., St. Louis /Iowa State U. /Natl. U. of Ireland, Galway /Utah U. /McGill U. /Washington U., St. Louis /McGill U. /McGill U. /Purdue U. /Anderson U. /Galway-Mayo Inst. of Tech. /Iowa State U. /UCLA, & /more authors. Discovery of Very High Energy Gamma Rays from PKS 1424+240 and Multiwavelength Constraints on its Redshift. United States. https://doi.org/10.2172/1046386
Acciari, V A, /Harvard-Smithsonian Ctr. Astrophys., Aliu, E, /Delaware U., Bartol Inst., Arlen, T, /UCLA, Aune, T, /UC, Santa Cruz, Bautista, M, /McGill U., Beilicke, M. /Washington U., St. Louis, Benbow, W, /Harvard-Smithsonian Ctr. Astrophys., Bottcher, M, /Ohio U., Boltuch, D, /Delaware U., Bartol Inst., Bradbury, S M, /Leeds U., Buckley, J H, /Washington U., St. Louis, Bugaev, V, /Washington U., St. Louis, Byrum, K, /Argonne, Cannon, A, /University Coll., Dublin, Cesarini, A, /Natl. U. of Ireland, Galway, Chow, Y C, /UCLA, Ciupik, L, /Roosevelt U., Chicago, Cogan, P, /McGill U., Cui, W, /Purdue U., Duke, C, /Grinnell Coll., Falcone, A, /Penn State U. /Purdue U. /Utah U. /Roosevelt U., Chicago /Harvard-Smithsonian Ctr. Astrophys. /Purdue U. /Natl. U. of Ireland, Galway /Utah U. /University Coll., Dublin /McGill U. /Roosevelt U., Chicago /McGill U. /Delaware U., Bartol Inst. /Utah U. /Chicago U., EFI /Iowa State U. /Roosevelt U., Chicago /DePauw U. /Utah U. /Pittsburg State U. /Washington U., St. Louis /Iowa State U. /Natl. U. of Ireland, Galway /Utah U. /McGill U. /Washington U., St. Louis /McGill U. /McGill U. /Purdue U. /Anderson U. /Galway-Mayo Inst. of Tech. /Iowa State U. /UCLA, and /more authors. 2012. "Discovery of Very High Energy Gamma Rays from PKS 1424+240 and Multiwavelength Constraints on its Redshift". United States. https://doi.org/10.2172/1046386. https://www.osti.gov/servlets/purl/1046386.
@article{osti_1046386,
title = {Discovery of Very High Energy Gamma Rays from PKS 1424+240 and Multiwavelength Constraints on its Redshift},
author = {Acciari, V A and /Harvard-Smithsonian Ctr. Astrophys. and Aliu, E and /Delaware U., Bartol Inst. and Arlen, T and /UCLA and Aune, T and /UC, Santa Cruz and Bautista, M and /McGill U. and Beilicke, M. /Washington U., St. Louis and Benbow, W and /Harvard-Smithsonian Ctr. Astrophys. and Bottcher, M and /Ohio U. and Boltuch, D and /Delaware U., Bartol Inst. and Bradbury, S M and /Leeds U. and Buckley, J H and /Washington U., St. Louis and Bugaev, V and /Washington U., St. Louis and Byrum, K and /Argonne and Cannon, A and /University Coll., Dublin and Cesarini, A and /Natl. U. of Ireland, Galway and Chow, Y C and /UCLA and Ciupik, L and /Roosevelt U., Chicago and Cogan, P and /McGill U. and Cui, W and /Purdue U. and Duke, C and /Grinnell Coll. and Falcone, A and /Penn State U. /Purdue U. /Utah U. /Roosevelt U., Chicago /Harvard-Smithsonian Ctr. Astrophys. /Purdue U. /Natl. U. of Ireland, Galway /Utah U. /University Coll., Dublin /McGill U. /Roosevelt U., Chicago /McGill U. /Delaware U., Bartol Inst. /Utah U. /Chicago U., EFI /Iowa State U. /Roosevelt U., Chicago /DePauw U. /Utah U. /Pittsburg State U. /Washington U., St. Louis /Iowa State U. /Natl. U. of Ireland, Galway /Utah U. /McGill U. /Washington U., St. Louis /McGill U. /McGill U. /Purdue U. /Anderson U. /Galway-Mayo Inst. of Tech. /Iowa State U. /UCLA and /more authors.},
abstractNote = {We report the first detection of very-high-energy (VHE) gamma-ray emission above 140GeV from PKS 1424+240, a BL Lac object with an unknown redshift. The photon spectrum above 140GeV measured by VERITAS is well described by a power law with a photon index of 3.8 {+-}0.5{sub stat} {+-} 0.3{sub syst} and a flux normalization at 200 GeV of (5.1 {+-} 0.9{sub stat} {+-} 0.5{sub syst}) x 10{sup -11} TeV{sup -1} cm{sup -2} s{sup -1}, where stat and syst denote the statistical and systematical uncertainty, respectively. The VHE flux is steady over the observation period between MJD 54881 and 55003 (2009 February 19 to June 21). Flux variability is also not observed in contemporaneous high energy observations with the Fermi Large Area Telescope (LAT). Contemporaneous X-ray and optical data were also obtained from the Swift XRT and MDM observatory, respectively. The broadband spectral energy distribution (SED) is well described by a one-zone synchrotron self-Compton (SSC) model favoring a redshift of less than 0.1. Using the photon index measured with Fermi in combination with recent extragalactic background light (EBL) absorption models it can be concluded from the VERITAS data that the redshift of PKS 1424+240 is less than 0.66.},
doi = {10.2172/1046386},
url = {https://www.osti.gov/biblio/1046386}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Apr 05 00:00:00 EDT 2012},
month = {Thu Apr 05 00:00:00 EDT 2012}
}