B.D. Lehmer
The 4 Ms Chandra Deep Field-South number counts apportioned by source class : pervasive active galactic nuclei and the ascent of normal galaxies
Lehmer, B.D.; Xue, Y.Q.; Brandt, W.N.; Alexander, D.M.; Bauer, F.E.; Brusa, M.; Comastri, A.; Gilli, R.; Hornschemeier, A.E.; Luo, B.; Paolillo, M.; Ptak, A.; Shemmer, O.; Schneider, D.P.; Tozzi, P.; Vignali, C.
Authors
Y.Q. Xue
W.N. Brandt
Professor David Alexander d.m.alexander@durham.ac.uk
Professor
F.E. Bauer
M. Brusa
A. Comastri
R. Gilli
A.E. Hornschemeier
B. Luo
M. Paolillo
A. Ptak
O. Shemmer
D.P. Schneider
P. Tozzi
C. Vignali
Abstract
We present 0.5-2 keV, 2-8 keV, 4-8 keV, and 0.5-8 keV (hereafter soft, hard, ultra-hard, and full bands, respectively) cumulative and differential number-count (log N-log S) measurements for the recently completed ≈4 Ms Chandra Deep Field-South (CDF-S) survey, the deepest X-ray survey to date. We implement a new Bayesian approach, which allows reliable calculation of number counts down to flux limits that are factors of ≈1.9-4.3 times fainter than the previously deepest number-count investigations. In the soft band (SB), the most sensitive bandpass in our analysis, the ≈4 Ms CDF-S reaches a maximum source density of ≈27,800 deg-2. By virtue of the exquisite X-ray and multiwavelength data available in the CDF-S, we are able to measure the number counts from a variety of source populations (active galactic nuclei (AGNs), normal galaxies, and Galactic stars) and subpopulations (as a function of redshift, AGN absorption, luminosity, and galaxy morphology) and test models that describe their evolution. We find that AGNs still dominate the X-ray number counts down to the faintest flux levels for all bands and reach a limiting SB source density of ≈14,900 deg-2, the highest reliable AGN source density measured at any wavelength. We find that the normal-galaxy counts rise rapidly near the flux limits and, at the limiting SB flux, reach source densities of ≈12,700 deg-2 and make up 46% ± 5% of the total number counts. The rapid rise of the galaxy counts toward faint fluxes, as well as significant normal-galaxy contributions to the overall number counts, indicates that normal galaxies will overtake AGNs just below the ≈4 Ms SB flux limit and will provide a numerically significant new X-ray source population in future surveys that reach below the ≈4 Ms sensitivity limit. We show that a future ≈10 Ms CDF-S would allow for a significant increase in X-ray-detected sources, with many of the new sources being cosmologically distant (z >~ 0.6) normal galaxies.
Citation
Lehmer, B., Xue, Y., Brandt, W., Alexander, D., Bauer, F., Brusa, M., …Vignali, C. (2012). The 4 Ms Chandra Deep Field-South number counts apportioned by source class : pervasive active galactic nuclei and the ascent of normal galaxies. Astrophysical Journal, 752(1), Article 46. https://doi.org/10.1088/0004-637x/752/1/46
Journal Article Type | Article |
---|---|
Publication Date | Jan 1, 2012 |
Deposit Date | Jun 13, 2012 |
Publicly Available Date | Dec 23, 2013 |
Journal | Astrophysical Journal |
Print ISSN | 0004-637X |
Electronic ISSN | 1538-4357 |
Publisher | American Astronomical Society |
Peer Reviewed | Peer Reviewed |
Volume | 752 |
Issue | 1 |
Article Number | 46 |
DOI | https://doi.org/10.1088/0004-637x/752/1/46 |
Keywords | Cosmology, Observations, Galaxies, Active, Starburst, X-rays. |
Files
Published Journal Article
(2.5 Mb)
PDF
Copyright Statement
© 2012. The American Astronomical Society. All rights reserved. Printed in the U.S.A.
You might also like
A new discovery space opened by eROSITA: Ionised AGN outflows from X-ray selected samples
(2023)
Journal Article
DESI z ≳ 5 Quasar Survey. I. A First Sample of 400 New Quasars at z ∼ 4.7–6.6
(2023)
Journal Article
The Quasar Feedback Survey: characterizing CO excitation in quasar host galaxies
(2023)
Journal Article
Obscuration beyond the nucleus: infrared quasars can be buried in extreme compact starbursts
(2023)
Journal Article
Downloadable Citations
About Durham Research Online (DRO)
Administrator e-mail: dro.admin@durham.ac.uk
This application uses the following open-source libraries:
SheetJS Community Edition
Apache License Version 2.0 (http://www.apache.org/licenses/)
PDF.js
Apache License Version 2.0 (http://www.apache.org/licenses/)
Font Awesome
SIL OFL 1.1 (http://scripts.sil.org/OFL)
MIT License (http://opensource.org/licenses/mit-license.html)
CC BY 3.0 ( http://creativecommons.org/licenses/by/3.0/)
Powered by Worktribe © 2024
Advanced Search