A search for pulsations from Geminga above 100 GeV with VERITAS

Connolly, M.P.
Gillanders, Gary
Moriarty, P.
Lang, Mark
Aliu, E,Archambault, S,Archer, A,Aune, T,Barnacka, A,Beilicke, M,Benbow, W,Bird, R,Buckley, JH,Bugaev, V,Byrum, K,Cardenzana, JV,Cerruti, M,Chen, X,Ciupik, L,Connolly, MP,Cui, W,Dickinson, HJ,Dumm, J,Eisch, JD,Errando, M,Falcone, A,Feng, Q,Finley, JP,Fleischhack, H,Fortin, P,Fortson, L,Furniss, A,Gillanders, GH,Griffin, S,Griffiths, ST,Grube, J,Gyuk, G,Kansson, NH,Hanna, D,Holder, J,Humensky, TB,Johnson, CA,Kaaret, P,Kar, P,Kertzman, M,Kieda, D,Krennrich, F,Kumar, S,Lang, MJ,Lyutikov, M,Madhavan, AS,Maier, G,McArthur, S,McCann, A,Meagher, K,Millis, J,Moriarty, P,Mukherjee, R,Nieto, D,de Bhroithe, AO,Ong, RA,Otte, AN,Park, N,Pohl, M,Popkow, A,Prokoph, H,Pueschel, E,Quinn, J,Ragan, K,Reyes, LC,Reynolds, PT,Richards, GT,Roache, E,Santander, M,Sembroski, GH,Shahinyan, K,Smith, AW,Staszak, D,T (2015) 'A SEARCH FOR PULSATIONS FROM GEMINGA ABOVE 100 GeV WITH VERITAS'. Astrophysical Journal, 800 .
We present the results of 71.6 hr of observations of the Geminga pulsar (PSR J0633+1746) with the VERITAS very-high-energy gamma-ray telescope array. Data taken with VERITAS between 2007 November and 2013 February were phase-folded using a Geminga pulsar timing solution derived from data recorded by the XMM-Newton and Fermi-LAT space telescopes. No significant pulsed emission above 100 GeV is observed, and we report upper limits at the 95% confidence level on the integral flux above 135 GeV (spectral analysis threshold) of 4.0x10(-13) s(-1) cm(-2) and 1.7 x 10(-13) s(-1) cm(-2) for the two principal peaks in the emission profile. These upper limits, placed in context with phase-resolved spectral energy distributions determined from 5 yr of data from the Fermi-Large Area Telescope (LAT), constrain possible hardening of the Geminga pulsar emission spectra above similar to 50 GeV.
American Astronomical Society
Publisher DOI
Attribution-NonCommercial-NoDerivs 3.0 Ireland