Near-IR search for lensed supernovae behind galaxy clusters: I. Observations and transient detection efficiency - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: Massive galaxy clusters at intermediate redshift can magnify the flux ofdistant background sources by several magnitudes and we exploit this effect tosearch for lensed distant supernovae that may otherwise be too faint to bedetected. A supernova search was conducted at near infrared wavelengths usingthe ISAAC instrument at the VLT. The galaxy clusters Abell 1689, Abell 1835 andAC114 were observed at multiple epochs of 2 hours of exposure time, separatedby a month. Image-subtraction techniques were used to search for transientobjects with light curve properties consistent with supernovae, both in our newand archival ISAAC-VLT data. The limiting magnitude of the individual epochswas estimated by adding artificial stars to the subtracted images. Most of theepochs reach 90% detection efficiency at SZJ ~= 23.8-24.0 mag Vega. Twotransient objects, both in archival images of Abell 1689 and AC114, weredetected. The transient in AC114 coincides - within the position uncertainty -with an X-ray source and is likely to be a variable AGN at the clusterredshift. The transient in Abell 1689 was found at SZ=23.24 mag, ~0.5 arcsecaway from a galaxy with photometric redshift z=0.6 +-0.15. The light curvesand the colors of the transient are consistent with a reddened Type IIPsupernova at redshift z=0.59 +- 0.05. The lensing model of Abell 1689 predicts~1.4 mag of magnification at the position of the transient, making it the mostmagnified supernova ever found and only the second supernova found behind agalaxy cluster. Our pilot survey has demonstrated the feasibility to finddistant gravitationally magnified supernovae behind massive galaxy clusters.One likely supernova was found behind Abell 1689, in accordance with theexpectations for this survey, as shown in an accompanying analysis paper.



Autor: V. Stanishev, A. Goobar, K. Paech, R. Amanullah, T. Dahlén, J. Jönsson, J. P. Kneib, C. Lidman, M. Limousin, E. Mörtsell, S. N

Fuente: https://arxiv.org/







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