Aims: We present the first public release of photometricredshifts galaxy rest frame properties and associated magnificationvalues in the cluster and parallel pointings of the first two FrontierFields Abell-2744 and MACS-J0416. The released catalogues aim toprovide a reference for future investigations of extragalacticpopulations in these legacy fields: from lensed high-redshift galaxiesto cluster members themselves. Methods: We exploit amultiwavelength catalogue ranging from Hubble Space Telescope (HST) toground-based K and Spitzer IRAC which is specifically designed toenable detection and measurement of accurate fluxes in crowded clusterregions. The multiband information is used to derive photometricredshifts and physical properties of sources detected either in theH-band image alone or from a stack of four WFC3 bands. To minimizesystematics median photometric redshifts are assembled from sixdifferent approaches to photo-z estimates. Their reliability is assessedthrough a comparison with available spectroscopic samples.State-of-the-art lensing models are used to derive magnification valueson an object-by-object basis by taking into account sources positionsand redshifts. Results: We show that photometric redshifts reacha remarkable ~3-5% accuracy. After accounting for magnification theH-band number counts are found to be in agreement at bright magnitudeswith number counts from the CANDELS fields while extending thepresently available samples to galaxies that intrinsically are asfaint as H ~ 32-33 thanks to strong gravitational lensing. The FrontierFields allow the galaxy stellar mass distribution to be probeddepending on magnification at 0.5-1.5 dex lower masses with respect toextragalactic wide fields including sources at M_star ~10^7-10^8 M_⊙ at z > 5. Similarlythey allow the detection of objects with intrinsic star formation rates(SFRs) >1 dex lower than in the CANDELS fields reaching 0.1-1M_⊙/yr at z ~ 6-10.
The ASTRODEEP Frontier Fields catalogues. II. Photometric redshifts and rest frame properties in Abell-2744 and MACS-J0416
Mercurio A;
2016-01-01
Abstract
Aims: We present the first public release of photometricredshifts galaxy rest frame properties and associated magnificationvalues in the cluster and parallel pointings of the first two FrontierFields Abell-2744 and MACS-J0416. The released catalogues aim toprovide a reference for future investigations of extragalacticpopulations in these legacy fields: from lensed high-redshift galaxiesto cluster members themselves. Methods: We exploit amultiwavelength catalogue ranging from Hubble Space Telescope (HST) toground-based K and Spitzer IRAC which is specifically designed toenable detection and measurement of accurate fluxes in crowded clusterregions. The multiband information is used to derive photometricredshifts and physical properties of sources detected either in theH-band image alone or from a stack of four WFC3 bands. To minimizesystematics median photometric redshifts are assembled from sixdifferent approaches to photo-z estimates. Their reliability is assessedthrough a comparison with available spectroscopic samples.State-of-the-art lensing models are used to derive magnification valueson an object-by-object basis by taking into account sources positionsand redshifts. Results: We show that photometric redshifts reacha remarkable ~3-5% accuracy. After accounting for magnification theH-band number counts are found to be in agreement at bright magnitudeswith number counts from the CANDELS fields while extending thepresently available samples to galaxies that intrinsically are asfaint as H ~ 32-33 thanks to strong gravitational lensing. The FrontierFields allow the galaxy stellar mass distribution to be probeddepending on magnification at 0.5-1.5 dex lower masses with respect toextragalactic wide fields including sources at M_star ~10^7-10^8 M_⊙ at z > 5. Similarlythey allow the detection of objects with intrinsic star formation rates(SFRs) >1 dex lower than in the CANDELS fields reaching 0.1-1M_⊙/yr at z ~ 6-10.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
