Bright galaxy sample in the Kilo-Degree Survey Data Release 4: selection, photometric redshifts, and physical properties
Bilicki, M.; Dvornik, A.; Hoekstra, H.; Wright, A. H.; Chisari, N. E.; Vakili, M.; Asgari, M.; Giblin, B.; Heymans, C.; Hildebrandt, H.; Holwerda, B. W.; Hopkins, A.; Johnston, H.; Kannawadi, A.; Kuijken, K.; Nakoneczny, S. J.; Shan, H. Y.; Sonnenfeld, A.; Valentijn, E.
(2021) Astronomy and Astrophysics, volume 653, pp. 1 - 19
(Article)
Abstract
We present a bright galaxy sample with accurate and precise photometric redshifts (photo-zs), selected using ugriZYJHKs photometry from the Kilo-Degree Survey (KiDS) Data Release 4. The highly pure and complete dataset is flux-limited at r < 20 mag, covers ∼1000 deg2, and contains about 1 million galaxies after artifact masking.
... read more
We exploit the overlap with Galaxy And Mass Assembly spectroscopy as calibration to determine photo-zs with the supervised machine learning neural network algorithm implemented in the ANNz2 software. The photo-zs have a mean error of |( δz) |∼5 × 10-4 and low scatter (scaled mean absolute deviation of ∼0.018(1 + z)); they are both practically independent of the r-band magnitude and photo-z at 0.05 < zphot < 0.5. Combined with the 9-band photometry, these allow us to estimate robust absolute magnitudes and stellar masses for the full sample. As a demonstration of the usefulness of these data, we split the dataset into red and blue galaxies, used them as lenses, and measured the weak gravitational lensing signal around them for five stellar mass bins. We fit a halo model to these high-precision measurements to constrain the stellar-mass-halo-mass relations for blue and red galaxies. We find that for high stellar mass (M• > 5 × 1011 Mo˙), the red galaxies occupy dark matter halos that are much more massive than those occupied by blue galaxies with the same stellar mass.
show less
Download/Full Text
Keywords: Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, galaxies: distances and redshifts, catalogs, large-scale structure of Universe, gravitational lensing: weak, methods: data analysis, Taverne
ISSN: 0004-6361
Publisher: EDP Sciences
Note: Funding Information: Acknowledgements. We thank the referee Gabriel Brammer for valuable suggestions on the paper and John Peacock for useful comments on the earlier version of the manuscript. Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under program IDs 177.A-3016, 177.A-3017 and 177.A-3018, and on data products produced by Target/OmegaCEN, INAF-OACN, INAF-OAPD and the KiDS production team, on behalf of the KiDS consortium. OmegaCEN and the KiDS production team acknowledge support by NOVA and NWO-M grants. Members of INAF-OAPD and INAF-OACN also acknowledge the support from the Department of Physics & Astronomy of the University of Padova, and of the Department of Physics of Univ. Federico II (Naples). GAMA is a joint European-Australasian project based around a spectroscopic campaign using the Anglo-Australian Telescope. The GAMA input catalog is based on data taken from the Sloan Digital Sky Survey and the UKIRT Infrared Deep Sky Survey. Complementary imaging of the GAMA regions is being obtained by a number of independent survey programs including GALEX MIS, VST KiDS, VISTA VIKING, WISE, Herschel-ATLAS, GMRT, and ASKAP providing UV to radio coverage. GAMA is funded by the STFC (UK), the ARC (Australia), the AAO, and the participating institutions. The GAMA website is http://www.gama-survey.org/. MBi is supported by the Polish National Science Center through grants no. 2020/38/E/ST9/00395, 2018/30/E/ST9/00698 and 2018/31/G/ST9/03388. MBi and SJN acknowledge the support from the Polish Ministry of Science and Higher Education through grant DIR/WK/2018/12. AD, AHW and HHi are supported by an European Research Council Consolidator Grant (No. 770935). HHo acknowledges support from the Netherlands Organisation for Scientific Research (NWO) through grant 639.043.512. This work is part of the Delta ITP consortium, a program of the Netherlands Organisation for Scientific Research (NWO) that is funded by the Dutch Ministry of Education, Culture and Science (OCW). MA, BG and CH acknowledge support from the European Research Council under grant number 647112. BG is supported by the Royal Society through an Enhancement Award (RGF/EA/181006). CH acknowledges support from the Max Planck Society and the Alexander von Humboldt Foundation in the framework of the Max Planck-Humboldt Research Award endowed by the Federal Ministry of Education and Research. HHi is supported by a Heisenberg grant of the Deutsche Forschungs-gemeinschaft (Hi 1495/5-1). KK acknowledges support from the Royal Society and Imperial College, SJN is supported by the Polish National Science Center through grant UMO-2018/31/N/ST9/03975. HYS acknowledges the support from NSFC of China under grant 11973070, the Shanghai Committee of Science and Technology grant No. 19ZR1466600 and Key Research Program of Frontier Sciences, CAS, Grant No. ZDBS-LY-7013. This work has made use of topcat (Taylor 2005) and stilts (Taylor 2006) software, as well as of python (www. python.org), including the packages NumPy (van der Walt et al. 2011), SciPy (Jones et al. 2001), and Matplotlib (Hunter 2007). Author contributions: All authors contributed to the development and writing of this paper. The authorship list is given in two groups: the lead authors (MB, AD, HHo, AHW, NEC, MV), followed by an alphabetical group which includes those who have either made a significant contribution to the data products, or to the scientific analysis. Publisher Copyright: © ESO 2021.
(Peer reviewed)
