TY - JOUR
T1 - Spectroscopic identification of a redshift 1.55 supernova host galaxy from the subaru deep field supernova survey
AU - Frederiksen, Teddy F.
AU - Graur, Or
AU - Hjorth, Jens
AU - Maoz, Dan
AU - Poznanski, Dovi
N1 - Funding Information:
We thank the anonymous referee for valuable comments that improved this manuscript. We also thank Martin Sparre for providing his X-shooter meta-pipeline, which simplified the reduction of the X-shooter spectra significantly. The Dark Cosmology Centre is funded by the Danish National Research Foundation. D.M. and O.G. acknowledge support by a grant from the Israel Science Foundation. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
PY - 2014/3
Y1 - 2014/3
N2 - Context. The Subaru Deep Field (SDF) Supernova Survey discovered ten Type Ia supernovae (SNe Ia) in the redshift range 1.5 < z < 2.0, determined solely from photometric redshifts of the host galaxies. However, photometric redshifts might be biased, and the SN sample could be contaminated by active galactic nuclei (AGNs). Aims. We aim to obtain the first robust redshift measurement and classification of a z > 1.5 SDF SN Ia host galaxy candidate. Methods. We use the X-shooter (U-to-K-band) spectrograph on the Very Large Telescope to allow the detection of different emission lines in a wide spectral range. Results. We measure a spectroscopic redshift of 1.54563 ± 0.00027 of hSDF0705.25, consistent with its photometric redshift of 1.552 ± 0.018. From the strong emission-line spectrum we rule out AGN activity, thereby confirming the optical transient as a SN. The host galaxy follows the fundamental metallicity relation showing that the properties of this high-redshift SN Ia host galaxy is similar to other field galaxies. Conclusions. Spectroscopic confirmation of additional SDF SN hosts would be required to confirm the cosmic SN rate evolution measured in the SDF.
AB - Context. The Subaru Deep Field (SDF) Supernova Survey discovered ten Type Ia supernovae (SNe Ia) in the redshift range 1.5 < z < 2.0, determined solely from photometric redshifts of the host galaxies. However, photometric redshifts might be biased, and the SN sample could be contaminated by active galactic nuclei (AGNs). Aims. We aim to obtain the first robust redshift measurement and classification of a z > 1.5 SDF SN Ia host galaxy candidate. Methods. We use the X-shooter (U-to-K-band) spectrograph on the Very Large Telescope to allow the detection of different emission lines in a wide spectral range. Results. We measure a spectroscopic redshift of 1.54563 ± 0.00027 of hSDF0705.25, consistent with its photometric redshift of 1.552 ± 0.018. From the strong emission-line spectrum we rule out AGN activity, thereby confirming the optical transient as a SN. The host galaxy follows the fundamental metallicity relation showing that the properties of this high-redshift SN Ia host galaxy is similar to other field galaxies. Conclusions. Spectroscopic confirmation of additional SDF SN hosts would be required to confirm the cosmic SN rate evolution measured in the SDF.
KW - Galaxies: distances and redshifts
KW - Galaxies: high-redshift
KW - Galaxy: abundances
UR - http://www.scopus.com/inward/record.url?scp=84897004375&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201321795
DO - 10.1051/0004-6361/201321795
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AN - SCOPUS:84897004375
SN - 0004-6361
VL - 563
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A140
ER -