Abstract
We present the first results of a wide-area X-ray survey within the Sloan Digital Sky Survey Stripe 82, a 300 deg2 region of the sky with a substantial investment in multiwavelength coverage. We analysed archival Chandra observations that cover 6.2 deg2 within Stripe 82 ('Stripe 82 ACX'), reaching 4.5s flux limits of 1.2 × 10-15, 5.4 × 10-15 and 2.9 × 10-15 erg s-1 cm-2 in the soft (0.5-2 keV), hard (2-7 keV) and full (0.5-7 keV) bands, to find 480, 137 and 705 X-ray sources, respectively. 214 sources are detected only in the full band and 4 sources are detected solely in the soft band. Utilizing data products from the Chandra Source Catalog, we construct independent logN-log S relationships, detailing the number density of X-ray sources as a function of flux. The soft and full bands show general agreement with previous Chandra surveys; the hard band number counts agree among Stripe 82 ACX, XBoötes and XDEEP2, but all three are somewhat systematically lower than the counts derived from Chandra Multiwavelength Project. We compare the luminosity distribution of Stripe 82 ACX with the smaller, deeper Chandra Deep Field-South, Extended Chandra Deep Field-South and Chandra-COSMOS surveys to illustrate the benefit of wide-area surveys in locating high-luminosity and/or high-redshift active galactic nuclei (AGN). Finally, we compare the identified AGN with predictions from population synthesis models, noting that prior to any spectroscopic follow-up campaign, we have already located roughly half the high-luminosity quasars at high redshift expected to lie within the survey area. However, our data also suggest that refinements to population synthesis models will be required.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1351-1360 |
| Number of pages | 10 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 432 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jun 1 2013 |
| Externally published | Yes |
Fingerprint
Keywords
- Galaxies: active
- Quasars: general
- Surveys
- X-rays: galaxies
- X-rays: general
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Cite this
Finding rare AGN : X-ray number counts of Chandra sources in Stripe 82. / LaMassa, Stephanie M.; Urry, C. Megan; Glikman, Eilat; Cappelluti, Nico; Civano, Francesca; Comastri, Andrea; Treister, Ezequiel; Arifin; Böhringer, Hans; Cardamone, Carie; Chon, Gayoung; Kephart, Miranda; Murray, Stephen S.; Richards, Gordon; Ross, Nicholas P.; Rozner, Joshua S.; Schawinski, Kevin.
In: Monthly Notices of the Royal Astronomical Society, Vol. 432, No. 2, 01.06.2013, p. 1351-1360.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Finding rare AGN
T2 - X-ray number counts of Chandra sources in Stripe 82
AU - LaMassa, Stephanie M.
AU - Urry, C. Megan
AU - Glikman, Eilat
AU - Cappelluti, Nico
AU - Civano, Francesca
AU - Comastri, Andrea
AU - Treister, Ezequiel
AU - Arifin,
AU - Böhringer, Hans
AU - Cardamone, Carie
AU - Chon, Gayoung
AU - Kephart, Miranda
AU - Murray, Stephen S.
AU - Richards, Gordon
AU - Ross, Nicholas P.
AU - Rozner, Joshua S.
AU - Schawinski, Kevin
PY - 2013/6/1
Y1 - 2013/6/1
N2 - We present the first results of a wide-area X-ray survey within the Sloan Digital Sky Survey Stripe 82, a 300 deg2 region of the sky with a substantial investment in multiwavelength coverage. We analysed archival Chandra observations that cover 6.2 deg2 within Stripe 82 ('Stripe 82 ACX'), reaching 4.5s flux limits of 1.2 × 10-15, 5.4 × 10-15 and 2.9 × 10-15 erg s-1 cm-2 in the soft (0.5-2 keV), hard (2-7 keV) and full (0.5-7 keV) bands, to find 480, 137 and 705 X-ray sources, respectively. 214 sources are detected only in the full band and 4 sources are detected solely in the soft band. Utilizing data products from the Chandra Source Catalog, we construct independent logN-log S relationships, detailing the number density of X-ray sources as a function of flux. The soft and full bands show general agreement with previous Chandra surveys; the hard band number counts agree among Stripe 82 ACX, XBoötes and XDEEP2, but all three are somewhat systematically lower than the counts derived from Chandra Multiwavelength Project. We compare the luminosity distribution of Stripe 82 ACX with the smaller, deeper Chandra Deep Field-South, Extended Chandra Deep Field-South and Chandra-COSMOS surveys to illustrate the benefit of wide-area surveys in locating high-luminosity and/or high-redshift active galactic nuclei (AGN). Finally, we compare the identified AGN with predictions from population synthesis models, noting that prior to any spectroscopic follow-up campaign, we have already located roughly half the high-luminosity quasars at high redshift expected to lie within the survey area. However, our data also suggest that refinements to population synthesis models will be required.
AB - We present the first results of a wide-area X-ray survey within the Sloan Digital Sky Survey Stripe 82, a 300 deg2 region of the sky with a substantial investment in multiwavelength coverage. We analysed archival Chandra observations that cover 6.2 deg2 within Stripe 82 ('Stripe 82 ACX'), reaching 4.5s flux limits of 1.2 × 10-15, 5.4 × 10-15 and 2.9 × 10-15 erg s-1 cm-2 in the soft (0.5-2 keV), hard (2-7 keV) and full (0.5-7 keV) bands, to find 480, 137 and 705 X-ray sources, respectively. 214 sources are detected only in the full band and 4 sources are detected solely in the soft band. Utilizing data products from the Chandra Source Catalog, we construct independent logN-log S relationships, detailing the number density of X-ray sources as a function of flux. The soft and full bands show general agreement with previous Chandra surveys; the hard band number counts agree among Stripe 82 ACX, XBoötes and XDEEP2, but all three are somewhat systematically lower than the counts derived from Chandra Multiwavelength Project. We compare the luminosity distribution of Stripe 82 ACX with the smaller, deeper Chandra Deep Field-South, Extended Chandra Deep Field-South and Chandra-COSMOS surveys to illustrate the benefit of wide-area surveys in locating high-luminosity and/or high-redshift active galactic nuclei (AGN). Finally, we compare the identified AGN with predictions from population synthesis models, noting that prior to any spectroscopic follow-up campaign, we have already located roughly half the high-luminosity quasars at high redshift expected to lie within the survey area. However, our data also suggest that refinements to population synthesis models will be required.
KW - Galaxies: active
KW - Quasars: general
KW - Surveys
KW - X-rays: galaxies
KW - X-rays: general
UR - http://www.scopus.com/inward/record.url?scp=84878659247&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84878659247&partnerID=8YFLogxK
U2 - 10.1093/mnras/stt553
DO - 10.1093/mnras/stt553
M3 - Article
AN - SCOPUS:84878659247
VL - 432
SP - 1351
EP - 1360
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -