X-RAY PROPERTIES OF THE NORTHERN GALACTIC CAP SOURCES IN THE 58 MONTH SWIFT/BAT CATALOG
Abstract
We present a detailed X-ray spectral analysis of the non-beamed, hard X-ray selected active galactic nuclei (AGNs) in the northern Galactic cap of the 58 month Swift Burst Alert Telescope (Swift/BAT) catalog, consisting of 100 AGNs with b > 50 Degree-Sign . This sky area has excellent potential for further dedicated study due to a wide range of multi-wavelength data that are already available, and we propose it as a low-redshift analog to the 'deep field' observations of AGNs at higher redshifts (e.g., CDFN/S, COSMOS, Lockman Hole). We present distributions of luminosity, absorbing column density, and other key quantities for the catalog. We use a consistent approach to fit new and archival X-ray data gathered from XMM-Newton, Swift/XRT, ASCA, and Swift/BAT. We probe to deeper redshifts than the 9 month BAT catalog ((z) = 0.043 compared to (z) = 0.03 for the 9 month catalog), and uncover a broader absorbing column density distribution. The fraction of obscured (log N {sub H} {>=} 22) objects in the sample is {approx}60%, and 43%-56% of the sample exhibits 'complex' 0.4-10 keV spectra. We present the properties of iron lines, soft excesses, and ionized absorbers for the subset of objects with sufficient signal-to-noise ratio.more »
- Authors:
-
- Department of Astronomy, University of Maryland, College Park, MD (United States)
- Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)
- Atmospheric and Environmental Research, 131 Hartwell Avenue, Lexington, MA (United States)
- Publication Date:
- OSTI Identifier:
- 22167139
- Resource Type:
- Journal Article
- Journal Name:
- Astrophysical Journal
- Additional Journal Information:
- Journal Volume: 763; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; COMPTON EFFECT; DENSITY; GALAXY NUCLEI; HARD X RADIATION; IRON; KEV RANGE 01-10; LUMINOSITY; RED SHIFT; SIGNAL-TO-NOISE RATIO; SKY; TELESCOPES; UNIVERSE; X-RAY GALAXIES
Citation Formats
Vasudevan, Ranjan V., Mushotzky, Richard F., Shimizu, Thomas T., Brandt, William N., Schneider, Donald P., Nousek, John, Winter, Lisa M., and Baumgartner, Wayne H., E-mail: ranjan@astro.umd.edu. X-RAY PROPERTIES OF THE NORTHERN GALACTIC CAP SOURCES IN THE 58 MONTH SWIFT/BAT CATALOG. United States: N. p., 2013.
Web. doi:10.1088/0004-637X/763/2/111.
Vasudevan, Ranjan V., Mushotzky, Richard F., Shimizu, Thomas T., Brandt, William N., Schneider, Donald P., Nousek, John, Winter, Lisa M., & Baumgartner, Wayne H., E-mail: ranjan@astro.umd.edu. X-RAY PROPERTIES OF THE NORTHERN GALACTIC CAP SOURCES IN THE 58 MONTH SWIFT/BAT CATALOG. United States. https://doi.org/10.1088/0004-637X/763/2/111
Vasudevan, Ranjan V., Mushotzky, Richard F., Shimizu, Thomas T., Brandt, William N., Schneider, Donald P., Nousek, John, Winter, Lisa M., and Baumgartner, Wayne H., E-mail: ranjan@astro.umd.edu. 2013.
"X-RAY PROPERTIES OF THE NORTHERN GALACTIC CAP SOURCES IN THE 58 MONTH SWIFT/BAT CATALOG". United States. https://doi.org/10.1088/0004-637X/763/2/111.
@article{osti_22167139,
title = {X-RAY PROPERTIES OF THE NORTHERN GALACTIC CAP SOURCES IN THE 58 MONTH SWIFT/BAT CATALOG},
author = {Vasudevan, Ranjan V. and Mushotzky, Richard F. and Shimizu, Thomas T. and Brandt, William N. and Schneider, Donald P. and Nousek, John and Winter, Lisa M. and Baumgartner, Wayne H., E-mail: ranjan@astro.umd.edu},
abstractNote = {We present a detailed X-ray spectral analysis of the non-beamed, hard X-ray selected active galactic nuclei (AGNs) in the northern Galactic cap of the 58 month Swift Burst Alert Telescope (Swift/BAT) catalog, consisting of 100 AGNs with b > 50 Degree-Sign . This sky area has excellent potential for further dedicated study due to a wide range of multi-wavelength data that are already available, and we propose it as a low-redshift analog to the 'deep field' observations of AGNs at higher redshifts (e.g., CDFN/S, COSMOS, Lockman Hole). We present distributions of luminosity, absorbing column density, and other key quantities for the catalog. We use a consistent approach to fit new and archival X-ray data gathered from XMM-Newton, Swift/XRT, ASCA, and Swift/BAT. We probe to deeper redshifts than the 9 month BAT catalog ((z) = 0.043 compared to (z) = 0.03 for the 9 month catalog), and uncover a broader absorbing column density distribution. The fraction of obscured (log N {sub H} {>=} 22) objects in the sample is {approx}60%, and 43%-56% of the sample exhibits 'complex' 0.4-10 keV spectra. We present the properties of iron lines, soft excesses, and ionized absorbers for the subset of objects with sufficient signal-to-noise ratio. We reinforce previous determinations of the X-ray Baldwin (Iwasawa-Taniguchi) effect for iron K{alpha} lines. We also identify two distinct populations of sources; one in which a soft excess is well-detected and another where the soft excess is undetected, suggesting that the process responsible for producing the soft excess is not at work in all AGNs. The fraction of Compton-thick sources (log N {sub H} > 24.15) in our sample is {approx}9%. We find that 'hidden/buried AGNs' (which may have a geometrically thick torus or emaciated scattering regions) constitute {approx}14% of our sample, including seven objects previously not identified as hidden. Compton reflection is found to be important in a large fraction of our sample using joint XMM-Newton+BAT fits ((R) = 2.7 {+-} 0.75), indicating light bending or extremely complex absorption. High-energy cutoffs generally lie outside the BAT band (E > 200 keV) but are seen in some sources. We present the average 1-10 keV spectrum for the sample, which reproduces the 1-10 keV X-ray background slope as found for the brighter 9 month BAT AGN sample. The 2-10 keV log(N)-log(S) plot implies completeness down to fluxes a factor of {approx}4 fainter than seen in the 9 month catalog. We emphasize the utility of this northern Galactic cap sample for a wide variety of future studies on AGNs.},
doi = {10.1088/0004-637X/763/2/111},
url = {https://www.osti.gov/biblio/22167139},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 763,
place = {United States},
year = {Fri Feb 15 00:00:00 EST 2013},
month = {Fri Feb 15 00:00:00 EST 2013}
}