Studying the Ultraviolet Spectrum of the First Spectroscopically Confirmed Supernova at Redshift Two

Journal Article · 08 February 2018 · The Astrophysical Journal (Online)

DOI: https://doi.org/10.3847/1538-4357/aaa126 · OSTI ID:1422471

Smith, M. ; Sullivan, M. ; Nichol, R. C.; Galbany, L. ; D’Andrea, C. B.; Inserra, C. ; Lidman, C. ; Rest, A.; Schirmer, M. ; Filippenko, A. V. ; Zheng, W.; Cenko, S. Bradley ; Angus, C. R.; Brown, P. J. ; Davis, T. M.; Finley, D. A.; Foley, R. J.; González-Gaitán, S. ; Gutiérrez, C. P. ; Kessler, R. ; Kuhlmann, S.; Marriner, J.; Möller, A.; Nugent, P. E. ; Prajs, S. ; Thomas, R.; Wolf, R.; Zenteno, A.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J. ; Bechtol, K.; Benoit-Lévy, A.; Bertin, E.; Brooks, D. ; Burke, D. L. ; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Castander, F. J. ; Crocce, M.; Cunha, C. E.; Costa, L. N. da; Davis, C.; Desai, S.; Diehl, H. T.; Doel, P.; Eifler, T. F.; Flaugher, B.; Fosalba, P.; Frieman, J.; García-Bellido, J. ; Gaztanaga, E.; Gerdes, D. W. ; Goldstein, D. A. ; Gruen, D. ; Gruendl, R. A. ; Gschwend, J.; Gutierrez, G.; Honscheid, K.; James, D. J. ; Johnson, M. W. G.; Kuehn, K. ; Kuropatkin, N.; Li, T. S.; Lima, M.; Maia, M. A. G.; Marshall, J. L. ; Martini, P. ; Menanteau, F.; Miller, C. J.; Miquel, R. ; Ogando, R. L. C.; Petravick, D.; Plazas, A. A. ; Romer, A. K. ; Rykoff, E. S. ; Sako, M.; Sanchez, E. ; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M. ; Sobreira, F.; Suchyta, E.; Swanson, M. E. C. ; Tarle, G. ; Walker, A. R.

In this article, we present observations of DES16C2nm, the first spectroscopically confirmed hydrogen-free superluminous supernova (SLSN-I) at redshift $$z\approx 2$$. DES16C2nm was discovered by the Dark Energy Survey (DES) Supernova Program, with follow-up photometric data from the Hubble Space Telescope, Gemini, and the European Southern Observatory Very Large Telescope supplementing the DES data. Spectroscopic observations confirm DES16C2nm to be at z = 1.998, and spectroscopically similar to Gaia16apd (a SLSN-I at z = 0.102), with a peak absolute magnitude of $$U=-22.26\pm 0.06$$. The high redshift of DES16C2nm provides a unique opportunity to study the ultraviolet (UV) properties of SLSNe-I. Combining DES16C2nm with 10 similar events from the literature, we show that there exists a homogeneous class of SLSNe-I in the UV ($${\lambda }_{\mathrm{rest}}\approx 2500$$ Å), with peak luminosities in the (rest-frame) U band, and increasing absorption to shorter wavelengths. There is no evidence that the mean photometric and spectroscopic properties of SLSNe-I differ between low ($$z\lt 1$$) and high redshift ($$z\gt 1$$), but there is clear evidence of diversity in the spectrum at $${\lambda }_{\mathrm{rest}}\lt 2000\,\mathring{\rm A} $$, possibly caused by the variations in temperature between events. No significant correlations are observed between spectral line velocities and photometric luminosity. Using these data, we estimate that SLSNe-I can be discovered to z = 3.8 by DES. While SLSNe-I are typically identified from their blue observed colors at low redshift ($$z\lt 1$$), we highlight that at $$z\gt 2$$ these events appear optically red, peaking in the observer-frame z-band. Such characteristics are critical to identify these objects with future facilities such as the Large Synoptic Survey Telescope, Euclid, and the Wide-field Infrared Survey Telescope, which should detect such SLSNe-I to z = 3.5, 3.7, and 6.6, respectively.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Univ. of Chicago, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR); European Union (EU); National Science Foundation (NSF); TABASGO Foundation; National Research Council (NRC); National Aeronautics and Space Administration (NASA); Christopher R. Redlich Fund; Miller Institute for Basic Research in Science (U.C. Berkeley); Gordon and Betty Moore Foundation; Alfred P. Sloan Foundation; David and Lucile Packard Foundation; USDOE Office of Science (SC), High Energy Physics (HEP)
• Contributing Organization: The DES Collaboration; DES
• Grant/Contract Number: AC05-00OR22725; 615929; ST/N000688/1; AST-1311862; NNX15AR41G; AST-1518052; NAS 5-26555; AC02-05CH11231; AST-1138766; AST-1536171; AYA2015-71825; ESP2015-66861; FPA2015-68048; SEV-2016-0588; SEV-2016-0597; MDM-2015-0509; 240672; 291329; 306478; AC02-07CH11359; SC0009924
• OSTI ID: 1422471
• Alternate ID(s): OSTI ID: 1418144; OSTI ID: 1432248; OSTI ID: 1595618
• Report Number(s): arXiv:1712.04535; FERMILAB-PUB-17-380-AE; TRN: US1801605
• Journal Information: The Astrophysical Journal (Online), Vol. 854, Issue 1; ISSN 1538-4357
• Publisher: Institute of Physics (IOP)Copyright Statement
• Country of Publication: United States
• Language: English