Studying the Ultraviolet Spectrum of the First Spectroscopically Confirmed Supernova at redshift two
Abstract
We present observations of DES16C2nm, the first spectroscopically confirmed hydrogen-free superluminous supernova (SLSN-I) at redshift z~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=-22.260.06. The high redshift of DES16C2nm provides a unique opportunity to study the ultraviolet (UV) properties of SLSNe-I. Combining DES16C2nm with ten similar events from the literature, we show that there exists a homogeneous class of SLSNe-I in the UV (~2500A), 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<1) and high redshift (z>1), but there is clear evidence of diversity in the spectrum at <2000A, 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<1), we highlight that at z>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.
Keywords
Cite
@article{arxiv.1712.04535,
title = {Studying the Ultraviolet Spectrum of the First Spectroscopically Confirmed Supernova at redshift two},
author = {M. Smith and M. Sullivan and R. C. Nichol and L. Galbany and C. B. D'Andrea and C. Inserra and C. Lidman and A. Rest and M. Schirmer and A. V. Filippenko and W. Zheng and S. Bradley Cenko and C. R. Angus and P. J. Brown and T. M. Davis and D. A. Finley and S. Gonzalez-Gaitan and C. P. Gutierrez and R. Kessler and S. Kuhlmann and J. Marriner and A. Moller and P. E. Nugent and S. Prajs and R. Thomas and R. Wolf and A. Zenteno and T. M. C. Abbott and F. B. Abdalla and S. Allam and J. Annis and K. Bechtol and A. Benoit-Levy and E. Bertin and D. Brooks and D. L. Burke and A. Carnero Rosell and M. Carrasco Kind and J. Carretero and F. J. Castander and M. Crocce and C. E. Cunha and L. N. da Costa and C. Davis and S. Desai and H. T. Diehl and P. Doel and T. F. Eifler and B. Flaugher and P. Fosalba and J. Frieman and J. Garcia-Bellido and E. Gaztanaga and D. W. Gerdes and D. A. Goldstein and D. Gruen and R. A. Gruendl and J. Gschwend and G. Gutierrez and K. Honscheid and D. J. James and M. W. G. Johnson and K. Kuehn and N. Kuropatkin and T. S. Li and M. Lima and M. A. G. Maia and J. L. Marshall and P. Martini and F. Menanteau and C. J. Miller and R. Miguel and R. L. C. Ogando and D. Petravick and A. A. Plazas and A. K. Romer and E. S. Rykoff and M. Sako and E. Sanchez and V. Scarpine and R. Schindler and M. Schubnell and I. Sevilla-Noarbe and R. C. Smith and M. Soares-Santos and F. Sobreira and E. Suchyta and M. E. C. Swanson and G. Tarle and A. R. Walker},
journal= {arXiv preprint arXiv:1712.04535},
year = {2018}
}
Comments
Accepted for publication in ApJ