J/ApJS/268/57 Unobscured QSOs in ecliptic poles from KMTNet & PS1 (Byun+, 2023)
Photometric selection of unobscured QSOs at the ecliptic poles: KMTNet in the
south field and Pan-STARRS in the north field.
Byun W., Kim M., Sheen Y.-K., Lee D., Ho L.C., Ko J., Seon K.-I., Shim H.,
Kim D., Kim Y., Lee J.H., Jeong H., Woo J.-H., Jeong W.-S., Park B.-G.,
Kim S.C., Lee Y., Cha S.-M., Song H., Son D., Yang Y.
<Astrophys. J. Suppl. Ser., 268, 57 (2023)>
=2023ApJS..268...57B 2023ApJS..268...57B (SIMBAD/NED BibCode)
ADC_Keywords: QSOs; Photometry, UBVRI; Photometry, infrared;
Galactic pole, north; Galactic pole, south; Surveys
Keywords: Quasars; Photometry; Catalogs; Galaxies
Abstract:
We search for quasi-stellar objects (QSOs) in a wide area of the south
ecliptic pole (SEP) field, which has been and will continue to be
intensively explored through various space missions. For this purpose,
we obtain deep broadband optical images of the SEP field covering an
area of ∼14.5x14.5deg2 with the Korea Microlensing Telescope Network
(KMTNet). The 5σ detection limits for point sources in the BVRI
bands are estimated to be ∼22.59, 22.60, 22.98, and 21.85mag,
respectively. Utilizing data from the Wide-field Infrared Survey
Explorer, unobscured QSO candidates are selected among the optically
pointlike sources using mid-infrared (MIR) and optical-MIR colors. To
refine our selection further and eliminate any contamination not
adequately removed by the color-based selection, we perform spectral
energy distribution fitting with archival photometric data ranging
from optical to MIR. As a result, we identify a total of
2383 unobscured QSO candidates in the SEP field. We also apply a
similar method to the north ecliptic pole field using Pan-STARRS data
and obtain a similar result of identifying 2427 candidates. The
differential number count per area of our QSO candidates is in good
agreement with those measured from spectroscopically confirmed ones in
other fields. Finally, we compare the results with the literature and
discuss how this work will impact future studies, especially upcoming
space missions.
Description:
Aiming to provide complementary optical data for the SPHEREx mission,
we observed a wide area of the south ecliptic pole (SEP) field using
the Korea Microlensing Telescope Network (KMTNet) from 2019 December
to 2020 February, as a part of the KMTNet Nearby Galaxy Survey (KNGS;
see Byun+ 2022PASP..134i4104B 2022PASP..134i4104B). The central position of the full
coverage was set to be RA(J2000)∼4h44m,DE(J2000)~-53°.
KMTNet consists of three 1.6m telescopes located at three different
sites: Cerro-Tololo Inter-American Observatory (CTIO), South African
Astronomical Observatory (SAAO), and Siding Spring Observatory (SSO).
To select QSO candidates in the NEP field, we utilized Pan-STARRS1
archival data, which surveyed the Northern Hemisphere for DEC>-30°
using grizy filters. See Section 4.3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 318 4802 Catalog of QSO candidates in the SEP and NEP fields;
from erratum published in 2024, ApJS, 272, 50
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Description of file:
datafile.fits is the corrected table in FITS format from the erratum
published in 2024, ApJS, 272, 50
See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
II/328 : AllWISE Data Release (Cutri+ 2013)
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)
II/367 : The VISTA Hemisphere Survey (VHS) catalog DR5 (McMahon+, 2020)
VII/289 : SDSS quasar catalog, sixteenth data release (DR16Q) (Lyke+, 2020)
II/371 : The Dark Energy Survey (DES): Data Release 2 (Abbott+, 2021)
J/AJ/130/873 : Properties of BQS objects in the SDSS DR3 area (Jester+, 2005)
J/ApJ/642/673 : IR-selected obscured AGN candidates (Polletta+, 2006)
J/AJ/131/2766 : Quasar luminosity function from SDSS-DR3 (Richards+, 2006)
J/AJ/132/999 : SDSS quasar lens search (Oguri+, 2006)
J/AJ/133/2222 : Clustering of high-redshift QSOs from SDSS (Shen+, 2007)
J/ApJ/663/81 : SED of hard X-ray selected AGN in XMDS (Polletta+, 2007)
J/AJ/136/2373 : Type 2 quasars from SDSS (Reyes+, 2008)
J/ApJ/690/1236 : COSMOS photometric redshift catalog (Ilbert+, 2009)
J/A+A/514/A11 : SEDs in ADFS (AKARI Deep Field South) (Malek+, 2010)
J/MNRAS/411/373 : Catalog of AKARI Deep Field South (Clements+, 2011)
J/A+A/537/A24 : AKARI NEP-Deep field mid-IR source catalogue (Takagi+, 2012)
J/ApJ/750/99 : The Pan-STARRS1 photometric system (Tonry+, 2012)
J/ApJ/804/27 : NIR photometry of hot dust-obscured galaxies (Assef+, 2015)
J/ApJ/849/53 : Composite SEDs of type 1 and type 2 QSOs (Hickox+, 2017)
J/A+A/610/A31 : 0.8-2.5um spectra of 2 red quasars (Kim+, 2018)
J/ApJS/234/23 : The WISE AGN candidates catalogs (Assef+, 2018)
J/ApJS/238/37 : Opt. & NIR sp. atlas of 16 2MASS NIR-red AGNs (Kim+, 2018)
J/ApJ/910/124 : Star formation rates of low-z QSOs from 1-500um (Xie+, 2021)
J/A+A/651/A108 : AGN catalog from the AKARI NEP Wide field (Poliszczuk+, 2021)
J/ApJ/923/262 : NIR spectroscopic obs. of z>6.5 quasars (Yang+, 2021)
J/ApJS/264/9 : Southern phot. QSOs from DES DR2 & NIR surveys (Yang+, 2023)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [QEP]
4- 20 A17 --- QEP QEP identifier (HHMMSS.s+DDMMSS.s; J2000) (ID)
22- 30 F9.5 deg RAdeg [57/287] Right ascension of the object's
centroid (J2000) (RA)
32- 40 F9.5 deg DEdeg [-61/73] Declination of the object's
centroid (J2000) (DEC)
42- 48 F7.4 mag Bmag [15.5/21.7]? KMTNet B-band AUTO magnitude
(Bmag) (1)
50- 55 F6.4 mag e_Bmag [0.001/0.2]? Uncertainty on Bmag (err_Bmag)
57- 63 F7.4 mag Vmag [15.2/21.5]? KMTNet V-band AUTO magnitude
(Vmag) (1)
65- 70 F6.4 mag e_Vmag [0.001/0.2]? Uncertainty on Vmag (err_Vmag)
72- 78 F7.4 mag Rmag [15/21.3]? KMTNet R-band AUTO magnitude
(Rmag) (1)
80- 85 F6.4 mag e_Rmag [0.0008/0.05]? Uncertainty on Rmag (err_Rmag)
87- 93 F7.4 mag Imag [14.5/19.5]? KMTNet I-band AUTO magnitude
(Imag) (1)
95- 100 F6.4 mag e_Imag [0.0008/0.07]? Uncertainty on Imag (err_Imag)
102- 108 F7.4 mag gmag [14/22.1]? Pan-STARRS g-band magnitude (gmag)
110- 115 F6.4 mag e_gmag [0.0003/0.4]? Uncertainty on gmag (err_gmag)
117- 123 F7.4 mag rmag [13.9/21.4]? Pan-STARRS r-band magnitude (rmag)
125- 130 F6.4 mag e_rmag [0.001/0.2]? Uncertainty on rmag (err_rmag)
132- 138 F7.4 mag imag [14/20]? Pan-STARRS i-band magnitude (imag)
140- 145 F6.4 mag e_imag [0.002/0.2]? Uncertainty on imag (err_imag)
147- 153 F7.4 mag zmag [13.2/20.6]? Pan-STARRS z-band magnitude (zmag)
155- 160 F6.4 mag e_zmag [0.0002/0.3]? Uncertainty on zmag (err_zmag)
162- 168 F7.4 mag ymag [13.8/20.4]? Pan-STARRS y band magnitude (ymag)
170- 175 F6.4 mag e_ymag [0/0.5]? Uncertainty on ymag (err_ymag)
177- 182 F6.3 mag Jmag [12.8/17.6]? 2MASS J-band magnitude (Jmag)
184- 188 F5.3 mag e_Jmag [0.02/0.4]? Uncertainty on Jmag (err_Jmag)
190- 195 F6.3 mag Hmag [12.1/17]? 2MASS H-band magnitude (Hmag)
197- 201 F5.3 mag e_Hmag [0.02/0.4]? Uncertainty on Hmag (err_Hmag)
203- 208 F6.3 mag Ksmag [11.1/16.4]? 2MASS Ks band magnitude (Kmag)
210- 214 F5.3 mag e_Ksmag [0.01/0.4]? Uncertainty on Ksmag (err_Kmag)
216- 222 F7.4 mag VJmag [14.3/20.4]? VHS J band magnitude (VJmag)
224- 229 F6.4 mag e_VJmag [0.002/1]? Uncertainty on VJmag (err_VJmag)
231- 237 F7.4 mag VHmag [13.8/20.6]? VHS H band magnitude (VHmag)
239- 244 F6.4 mag e_VHmag [0.005/3]? Uncertainty on VHmag (err_VHmag)
246- 252 F7.4 mag VKmag [12.8/19.2]? VHS Ks band magnitude (VKmag)
254- 259 F6.4 mag e_VKmag [0.004/1.4]? Uncertainty on VKmag (err_VKmag)
261- 266 F6.3 mag W1mag [9.4/17.5] WISE W1 (3.4um) band magnitude (W1mag)
268- 272 F5.3 mag e_W1mag [0.02/0.5] Uncertainty on W1mag (err_W1mag)
274- 279 F6.3 mag W2mag [8.3/16.5] WISE W2 (4.6um) band magnitude (W2mag)
281- 285 F5.3 mag e_W2mag [0.02/0.2] Uncertainty on W2mag (err_W2mag)
287- 292 F6.3 mag W3mag [5.7/13.7] WISE W3 (12um) band magnitude (W3mag)
294- 298 F5.3 mag e_W3mag [0.01/0.5] Uncertainty on W3mag (err_W3mag)
300- 305 F6.3 mag W4mag [3.1/10.3] WISE W4 (22um) band magnitude (W4mag)
307- 311 F5.3 mag e_W4mag [0.01/0.6]? Uncertainty on W4mag (err_W4mag)
313 A1 --- Field [NS] Object in the SEP field ("S") or
in the NEP field ("N") (flag1)
315- 318 A4 --- OCat [FY, ] Object identified in other publication(s)
(flag2) (2)
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Note (1): Detailed information on the SEP observations with KMTNet:
-----------------------------------------------------------
Filt Site Texp Ntotal ZP mlimit
(s) (mag) (mag)
-----------------------------------------------------------
B SSO 85 147 + 18 28.02±0.09 22.59
V SSO 85 147 + 25 28.18±0.10 22.60
R CTIO 85 147 - 14 28.95±0.04 22.98
I SAAO 85 147 + 28 28.44±0.06 21.85
-----------------------------------------------------------
Texp is the exposure time of a single frame, and Ntotal is the
total number of frames used to create the final mosaic image. The
frames were obtained by visiting 7x7 patches sequentially with
individual three-point dithering, yielding a median integration
time per patch of 255s. ZP and mlimit are the zero-point magnitude
and 5σ detection limit, respectively.
Note (2): Other paper identifying this object as follows:
F = Flesch, Eric W. 2021arXiv210512985F 2021arXiv210512985F (404+268 occurrences)
Y = Yang & Shen 2023, J/ApJS/264/9 (2072+268 occurrences)
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History:
From electronic version of the journal
09-Feb-2024: Insert into VizieR
20-Jun-2024: Table corrected with erratum published in 2024, ApJS, 272, 50
(End) Emmanuelle Perret [CDS] 19-Jan-2024