Details

Autor(en) / Beteiligte

• Bizzocchi, Luca
• Filho, Mercedes E
• Leonardo, Elvira
• Grossi, Marco
• Griffith, Roger L
• Afonso, Jose
• Fernandes, Cristina
• RETRE, JOAO
• Anton, Sonia
• Bell, Eric F
• Brinchmann, Jarle
• Henriques, Bruno
• Lobo, Catarina
• Messias, Hugo

Titel

BULGELESS GALAXIES AT INTERMEDIATE REDSHIFT: SAMPLE SELECTION, COLOR PROPERTIES, AND THE EXISTENCE OF POWERFUL ACTIVE GALACTIC NUCLEI

Ist Teil von

• The Astrophysical journal, 2014-02, Vol.782 (1), p.1-20

Ort / Verlag

United States

Erscheinungsjahr

2014

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• We present a catalog of bulgeless galaxies, which includes 19,225 objects selected in four of the deepest, largest multi-wavelength data sets available-COSMOS, AEGIS, GEMS, and GOODS-at intermediate redshift (0.4 [< or =, slant] z [< or =, slant] 1.0). The morphological classification was provided by the Advanced Camera for Surveys General Catalog (ACS-GC), which used publicly available data obtained with the ACS instrument on the Hubble Space Telescope. Rest-frame photometric quantities were derived using kcorrect. We analyze the properties of the sample and the evolution of pure-disk systems with redshift. Very massive [log(M sub(*)/M sub([middot in circle])) > 10.5] bulgeless galaxies contribute to ~30% of the total galaxy population number density at z [> or =, slanted] 0.7, but their number density drops substantially with decreasing redshift. We show that only a negligible fraction of pure disks appear to be quiescent systems, and red sequence bulgeless galaxies show indications of dust-obscured star formation. X-ray catalogs were used to search for X-ray emission within our sample. After visual inspection and detailed parametric morphological fitting we identify 30 active galactic nuclei (AGNs) that reside in galaxies without a classical bulge. The finding of such peculiar objects at intermediate redshift shows that while AGN growth in merger-free systems is a rare event (0.2% AGN hosts in this sample of bulgeless galaxies), it can indeed happen relatively early in the history of the universe.