Introducing the FLAMINGOS-2 Split-K Medium-band Filters: The Impact on Photometric Selection of High-z Galaxies in the FENIKS-pilot survey Academic Article uri icon


  • Abstract Deep near-infrared photometric surveys are efficient in identifying high-redshift galaxies, however, they can be prone to systematic errors in photometric redshift. This is particularly salient when there is limited sampling of key spectral features of a galaxys spectral energy distribution (SED), such as for quiescent galaxies where the expected age-sensitive Balmer/4000 break enters the K-band at z > 4. With single-filter sampling of this spectral feature, degeneracies between SED models and redshift emerge. A potential solution to this comes from splitting the K band into multiple filters. We use simulations to show an optimal solution is to add two medium-band filters, K blue ( cen = 2.06 m, = 0.25 m) and K red ( cen = 2.31 m, = 0.27 m), that are complementary to the existing K s filter. We test the impact of the K-band filters with simulated catalogs comprised of galaxies with varying ages and signal-to-noise. The results suggest that the K-band filters do improve photometric redshift constraints on z > 4 quiescent galaxies, increasing precision and reducing outliers by up to 90%. We find that the impact from the K-band filters depends on the signal-to-noise, the redshift, and the SED of the galaxy. The filters we designed were built and used to conduct a pilot of the FLAMINGOS-2 Extragalactic Near-Infrared K-band Split survey. While no new z > 4 quiescent galaxies are identified in the limited area pilot, the K blue and K red filters indicate strong Balmer/4000 breaks in existing candidates. Additionally, we identify galaxies with strong nebular emission lines, for which the K-band filters increase photometric redshift precision and in some cases indicate extreme star formation.

published proceedings


altmetric score

  • 1.25

author list (cited authors)

  • Esdaile, J., Labbe, I., Glazebrook, K., Antwi-Danso, J., Papovich, C., Taylor, E., ... Goodsell, S.

citation count

  • 6

complete list of authors

  • Esdaile, James||Labbe, Ivo||Glazebrook, Karl||Antwi-Danso, Jacqueline||Papovich, Casey||Taylor, Edward||Marsan, Z Cemile||Muzzin, Adam||Straatman, Caroline MS||Marchesini, Danilo||Diaz, Ruben||Spitler, Lee||Tran, Kim-Vy H||Goodsell, Stephen

publication date

  • December 2021