English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present photometric observations of an apparent Type Ia supernova (SN Ia)at a redshift of ~1.7, the farthest SN observed to date. SN 1997ff, wasdiscovered in a repeat observation by the HST of the HDF-), and serendipitouslymonitored with NICMOS on HST throughout the GTO campaign. The SN type can bedetermined from the host galaxy type:an evolved, red elliptical lacking enoughrecent star formation to provide a significant population of core-collapse SNe.The class- ification is further supported by diagnostics available from theobserved colors and temporal behavior of the SN, both of which match a typicalSN Ia. The photo- metric record of the SN includes a dozen flux measurements inthe I, J, and H bands spanning 35 days in the observed frame. The redshiftderived from the SN photometry, z=1.7+/-0.1, is in excellent agreement with theredshift estimate of z=1.65+/-0.15 derived from theU_300,B_450,V_606,I_814,J_110,J_125,H_160, H_165,K_s photometry of the galaxy.Optical and near-infrared spectra of the host provide a very tentativespectroscopic redshift of 1.755. Fits to observations of the SN provideconstraints for the redshift-distance relation of SNe~Ia and a powerful test ofthe current accelerating Universe hypothesis. The apparent SN brightness isconsistent with that expected in the decelerating phase of the preferredcosmological model, Omega_M~1/3, Omega_Lambda~2/3. It is inconsistent with greydust or simple luminosity evolution, candidate astro- physical effects whichcould mimic past evidence for an accelerating Universe from SNe Ia at z~0.5.Weconsider several sources of possible systematic error including lensing, SNmisclassification, selection bias, and calibration errors. Currently, none ofthese effects appears likely to challenge our conclusions.

The Farthest Known Supernova: Support for an Accelerating Universe and a Glimpse of the Epoch of Deceleration