Spectroscopic Redshift of the Gamma-Ray Blazar B2 1215+30 from Lyα Emission

Furniss, A.; Worseck, G.; Fumagalli, M.; Johnson, C.A.; Williams, D.A.; Pontrelli, P.; Prochaska, J.X.

Abstract

We report on Cosmic Origin Spectrograph observations of the gamma-ray bright blazar B2 1215+30, collected in 2015 November. These observations allow for the confirmation of the source redshift from the detection of a Lyα emission feature at λ ~ 1374 Å. The emission feature places the source at a redshift of z = 0.1305 ± 0.003, confirming the source's ground-based spectral measurement. The gamma-ray emission of the source is discussed in the context of the source distance, required for the accurate reconstruction of the intrinsic gamma-ray emission taking the absorption by the extragalactic background light into account. The source distance is found to be low enough that the previously reported detection of an exceptional flaring event from B2 1215+30 in 2014 cannot be used to investigate opacity-specific spectral and variability characteristics introduced by possible ultra-high-energy cosmic-ray propagation.

Citation

Furniss, A., Worseck, G., Fumagalli, M., Johnson, C., Williams, D., Pontrelli, P., & Prochaska, J. (2019). Spectroscopic Redshift of the Gamma-Ray Blazar B2 1215+30 from Lyα Emission. Astronomical Journal, 157(2), Article 41. https://doi.org/10.3847/1538-3881/aaf28b

• Journal Article Type: Article
• Acceptance Date: Nov 18, 2018
• Online Publication Date: Jan 7, 2019
• Publication Date: Jan 7, 2019
• Deposit Date: Jan 23, 2019
• Publicly Available Date: Jan 23, 2019
• Journal: Astronomical Journal
• Print ISSN: 0004-6256
• Electronic ISSN: 1538-3881
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 157
• Issue: 2
• Article Number: 41
• DOI: https://doi.org/10.3847/1538-3881/aaf28b
• Public URL: https://durham-repository.worktribe.com/output/1339158