Constraining dust and color variations of high-z SNe using NICMOS on Hubble Space Telescope

TL;DR

This study uses NICMOS on the Hubble Space Telescope to analyze high-redshift Type Ia supernovae, constraining dust effects and confirming a flat universe, while comparing their properties to nearby supernovae.

Contribution

It provides new infrared observations of high-z SNe Ia, doubling the sample on the I-band Hubble diagram and testing dust models against the data.

Findings

Data supports a flat universe with Omega_Matter=0.29 and Omega_Lambda=0.71.

Replenishing large grain dust in intergalactic medium is inconsistent with observations.

Most high-z SNe Ia show expected color evolution, except one with peculiar behavior.

Abstract

We present data from the Supernova Cosmology Project for five high redshift Type Ia supernovae (SNe Ia) that were obtained using the NICMOS infrared camera on the Hubble Space Telescope. We add two SNe from this sample to a rest-frame I-band Hubble diagram, doubling the number of high redshift supernovae on this diagram. This I-band Hubble diagram is consistent with a flat universe (Omega_Matter, Omega_Lambda= 0.29, 0.71). A homogeneous distribution of large grain dust in the intergalactic medium (replenishing dust) is incompatible with the data and is excluded at the 5 sigma confidence level, if the SN host galaxy reddening is corrected assuming R_V=1.75. We use both optical and infrared observations to compare photometric properties of distant SNe Ia with those of nearby objects. We find generally good agreement with the expected color evolution for all SNe except the highest redshift SN in our sample (SN 1997ek at z=0.863) which shows a peculiar color behavior. We also present spectra obtained from ground based telescopes for type identification and determination of redshift.