Very high energy \(\gamma\)-ray emission from two blazars of unknown redshift and upper limits on their distance

• Published in: arXiv.org 2020-04
• Main Authors: Abdalla, H, Adam, R, Aharonian, F, Arakawa, M, Arcaro, C, Armstrong, T, Ashkar, H, Backes, M, Barnard, M, Becherini, Y, Brun, P, Bylund, T, Carosi, A, Chen, A, Cotter, G, Deil, C, Dirson, L, Doroshenko, V, Dyks, J, Egberts, K, Eichhorn, F, Funk, S, Gallant, Y A, Giavitto, G, Giunti, L, Gottschall, D, M -H Grondin, Hahn, J, Haupt, M, Hinton, J A, Hofmann, W, Holch, T L, M H{\"}orbe, Huber, D, Iwasaki, H, Jamrozy, M, Jankowsky, F, Joshi, V, Jung-Richardt, I, Kastendieck, M A, Katarzynski, K, Katz, U, Klepser, S, Konno, R, Kosack, K, Kreter, M, Lamanna, G, Leser, E, Levy, C, Lypova, I, Mares, A, Maurin, G, Meintjes, P J, Moderski, R, Morris, P, Moulin, E, de Naurois, M, Oakes, L, O'Brien, P, Ohm, S, E de Ona Wilhelmi, Panter, M, Parsons, R D, Poireau, V, Raab, S, Remy, Q, Renaud, M, Rieger, F, Rinchiuso, L, Rowell, G, Rudak, B, Ruiz-Velasco, E, Sailer, S, Sanchez, D A, Schüssler, F, Schwanke, U, Schwemmer, S, Seglar-Arroyo, M, Senniappan, M, Shafi, N, Shiningayamwe, K, Spencer, S, Spir-Jacob, M, Stawarz, Ł, Steenkamp, R, Steppa, C, Tavernier, T, Taylor, A M, Tluczykont, M, Tsirou, M, D J van der Walt, C van Eldik, C van Rensburg, Venter, C, Wadiasingh, Z, Werner, F, Wierzcholska, A, Yang, R, Zacharias, M, Zdziarski, A A
• Format: Article
• Language: English
• Subjects: BL Lacertae objects; Confidence intervals; Gamma rays; Red shift; Stereoscopy
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2004.03306

We report on the detection of very-high-energy (VHE; \(E > 100\) GeV) \(\gamma\)-ray emission from the BL Lac objects KUV 00311-1938 and PKS 1440-389 with the High Energy Stereoscopic System (H.E.S.S.). H.E.S.S. observations were accompanied or preceded by multi-wavelength observations with Fermi/LAT, XRT and UVOT on board the Swift satellite, and ATOM. Based on an extrapolation of the Fermi/LAT spectrum towards the VHE \(\gamma\)-ray regime, we deduce a 95% confidence level upper limit on the unknown redshift of KUV 00311-1938 of z < 0.98, and of PKS 1440-389 of z < 0.53. When combined with previous spectroscopy results the redshift of KUV 00311-1938 is constrained to \(0.51 \leq z < 0.98\) and for PKS 1440-389 to \(0.14 \lessapprox z < 0.53\).