J/other/JHEAP/36.152 Radio Loud and Quiet QSOs X-ray properties (Shabana+, 2022)
X-ray properties of high-redshift Radio Loud and Radio Quiet Quasars observed
by Chandra.
Shabana F., Siemiginowskab A., Suleimanb R.M., El-Nawawya M.S., Alia A.
<Journal of High Energy Astrophysics, 36, 152-161 (2022)>
=2022JHEAp..36..152S 2022JHEAp..36..152S (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Redshifts ; X-ray sources
Keywords: radio loud quasars - radio quiet quasars - X-ray astrophysics -
X-ray photon index - hardness ratio
Abstract:
We performed a study of high redshift (z>2) quasars, looking for the
main differences between Radio Loud Quasars (RLQ) and Radio Quiet
Quasars (RQQ) in the X-ray band. Our sample of 472 RQQ and 81 RLQ was
selected by cross-matching the SDSS DR7 quasars catalog with the
Chandra Source Catalog. We computed the X-ray luminosity for the two
samples and confirmed the X-ray luminosity excess of RLQ over RQQ. We
fit the X-ray spectra assuming the absorbed power law model and
obtained the photon index (GAMMA) values for all the sources in the
sample. We excluded quasars with a low number of counts (<10) and
large uncertainty on the best-fit photon index (GAMMAerr>1), and
obtained the mean values of GAMMARLQ=1.70+0.36-0.33 and
GAMMARQQ=2.19+0.46-0.44 for the RLQ and RQQ samples,
respectively, showing that the RLQ have flatter (harder) X-ray spectra
than RQQ. The Kuiper-two test confirms this result with the
significant difference between the RLQ and RQQ photon index
distributions (Dk=0.37 and P-value=10-6). We also evaluated the
hardness ratio distributions and confirmed that the spectra of RLQ are
flatter than the spectra of the RQQ. The RLQ's hard-to-soft ratio
distribution is skewed towards the hard X-ray band, while the RQQ is
towards the soft X-ray band. The hard-to-medium and medium-to-soft
ratios show no difference.
Description:
We study the X-ray properties of quasars using archival data from two
quasar catalogs. We use DR7 quasars catalog (Shen et al.,
2011ApJS..194...45S 2011ApJS..194...45S, Cat. J/ApJS/194/45), which contains 105,783
quasars with optical spectra and redshift measurements. Shen et al.
(2011ApJS..194...45S 2011ApJS..194...45S, Cat. J/ApJS/194/45) quasars were selected from
the SDSS DR7 sample compiled by Schneider et al. (2010AJ....139.2360S 2010AJ....139.2360S,
Cat. VII/260) and all have spectroscopic redshift measurements.
We use the X-ray data obtained by the Chandra X-ray Observatory
(Chandra) during the first 15 years of the mission available in the
Chandra Source Catalog release 2.0 (CSC22). There are more than
315000 unique X-ray sources in the CSC2 (Evans et al., 2019, Cat.
IX/57).
After applying redshift and radio-loudness filters we obtained two
samples, one with 472 RQQ and the second with 81 RLQ. The two samples
have a similar redshift range, 2<z<5, with the RLQ sample being one
of the largest samples of RLQ within that redshift range to date.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
riq_18.dat 390 18 Radio intermediate quasars sample
rlq_81.dat 366 81 Radio loud quasars sample
rqq_472.dat 380 472 Radio quiet quasars sample
rlq_csc2.dat 188 13 Radio loud quasars CSC2 sample
rqq_csc2.dat 188 26 Radio quiet quasars CSC2 sample
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See also:
IX/57 : The Chandra Source Catalog (CSC), Release 2.0 (Evans+, 2019)
J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)
Byte-by-byte Description of file: riq_18.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- SDSS SDSS name, HHMMSS.ss+DDMMSS.s (SDSS_NAME)
20- 34 F15.11 deg RAdeg Right ascension (J2000) (RA_1)
36- 50 F15.11 deg DEdeg Delcination (J2000) (DEC_1)
52- 72 A21 --- CXC CXC name (2CXO JHHMMSS.s+DDMMSS) (CXC_NAME)
74- 89 F16.14 --- z Quasar redshift from DR7 catalog (Redshift)
91-107 F17.14 --- R Radio loudness (Radio_Loudness) (G1)
109-124 F16.13 [10-7W] logLX X-ray luminosity (Log (X-ray_Lum)) (G2)
126-141 F16.13 [10-7W] blogLX X-ray luminosity lower limit
(Log (X-rayLumlolim)) (G3)
143-158 F16.13 [10-7W] BlogLX X-ray luminosity upper limit
(Log (X-rayLumhilim)) (G4)
160-164 I5 --- ObsID Observation identifier (Obs_ID)
166-182 F17.15 --- PI ?=- Photon index (Photon_Index) (G5)
184-200 F17.15 --- B_PI ?=- Photon index upper limit
(PhotonIndexmax) (G6)
202-219 F18.15 --- b_PI []?=- Photon index lower limit
(PhotonIndexmin) (G7)
221-238 F18.15 --- HR-H/M Hard/medium hardness ratio (Hard_H/M) (G8)
240-257 F18.15 --- b_HR-H/M Hard/medium hardness ratio
68% lower confidence limit (HardH/Mlolim)
259-276 F18.15 --- B_HR-H/M Hard/medium hardness ratio
68% upper confidence limit (HardH/Mhilim)
278-295 F18.15 --- HR-H/S Hard/soft hardness ratio (Hard_H/S) (G9)
297-314 F18.15 --- b_HR-H/S Hard/soft hardness ratio
68% lower confidence limit (HardH/Slolim)
316-333 F18.15 --- B_HR-H/S Hard/soft hardness ratio
68% upper confidence limit (HardH/Shilim)
335-352 F18.15 --- HR-M/S Medium/Soft hardness ratio (Hard_M/S) (G10)
354-371 F18.15 --- b_HR-M/S Medium/Soft hardness ratio
68% lower confidence limit (HardM/Slolim)
373-390 F18.15 --- B_HR-M/S Medium/Soft hardness ratio
68% upper confidence limit (hardmshilim)
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Byte-by-byte Description of file: rlq_81.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- SDSS SDSS name, HHMMSS.ss+DDMMSS.s (SDSS_NAME)
20- 40 A21 --- CXC CXC name (2CXO JHHMMSS.s+DDMMSS) (CXC_NAME)
42- 47 F6.4 --- z Quasars redshift from DR7 catalog (Redshift)
49- 56 F8.4 deg RAdeg Right ascension (J2000) (RA)
58- 67 F10.6 deg DEdeg Delcination (J2000) (DEC)
69- 75 F7.5 --- R Radio loudness (Radio_Loudness) (G1)
77- 94 F18.15 --- HR-H/M Hard/medium hardness ratio (Hard_H/M) (G8)
96-113 F18.15 --- BHR-H/M Hard/medium hardness ratio
68% upper confidence limit (HardH/Mlolim)
115-132 F18.15 --- bHR-H/M Hard/medium hardness ratio
68% lower confidence limit (HardH/Mhilim)
134-151 F18.15 --- HR-M/S Hard/Medium hardness ratio (Hard_M/S) (G10)
153-170 F18.15 --- B_HR-M/S Hard/Medium hardness ratio
68% upper confidence limit (HardM/Shilim)
172-189 F18.15 --- b_HR-M/S Hard/Medium hardness ratio
68% lower confidence limit (HardM/Slolim)
191-208 F18.15 --- HR-H/S Hard/soft hardness ratio (Hard_H/S) (G9)
210-227 F18.15 --- BHR-H/S Hard/soft hardness ratio
68% upper confidence limit (HardH/Shilim)
229-246 F18.15 --- bHR-H/S Hard/soft hardness ratio
68% lower confidence limit (HardH/Slolim)
248-253 A6 --- ObsID Observation identifier (Obs_ID)
255-272 F18.15 --- PI ?=- Photon index (Photon_Index) (G5)
274-290 F17.15 --- B_PI ?=- Photon index upper limit
(PhotonIndexmax)
292-309 F18.15 --- b_PI ?=- Photon index lower limit
(PhotonIndexmin)
311-328 F18.15 [10-7W] logLX X-ray luminosity (Log (X-ray_Lum)) (G2)
330-347 F18.15 [10-7W] blogLX X-ray luminosity lower limit
(Log (X-rayLumlolim))
349-366 F18.15 [10-7W] BlogLX X-ray luminosity upper limit
(Log (X-rayLumhilim))
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Byte-by-byte Description of file: rqq_472.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- SDSS SDSS name, HHMMSS.ss+DDMMSS.s (SDSS_NAME)
20- 34 F15.11 deg RAdeg Right ascension (J2000) (RA)
36- 50 F15.11 deg DEdeg Delcination (J2000) (DEC)
52- 67 F16.14 --- z Quasars redshift from DR7 catalog (Redshift)
69- 89 A21 --- CXC CXC name (2CXO JHHMMSS.s+DDMMSS) (NAME)
91- 95 I5 --- ObsID ?=- Observation identifier (Obs_ID)
97-114 F18.15 --- HR-H/M ?=- Hard/medium hardness ratio (hard_hm) (G8)
116-133 F18.15 --- b_HR-H/M []?=- Hard/medium hardness ratio
68% lower confidence limit (hardhmlolim)
135-152 F18.15 --- B_HR-H/M []?=- Hard/medium hardness ratio
68% upper confidence limit (hardhmhilim)
154-171 F18.15 --- HR-H/S ?=- Hard/soft hardness ratio (hard_hs) (G9)
173-190 F18.15 --- b_HR-H/S []?=- Hard/soft hardness ratio
68% lower confidence limit (hardhslolim)
192-209 F18.15 --- B_HR-H/S []?=- Hard/soft hardness ratio
68% upper confidence limit (hardhshilim)
211-228 F18.15 --- HR-M/S ?=- Medium/Soft hardness ratio (hard_ms) (G10)
230-247 F18.15 --- b_HR-M/S []?=- Medium/Soft hardness ratio
68% lower confidence limit (hardmslolim)
249-266 F18.15 --- B_HR-M/S []?=- Medium/Soft hardness ratio
68% upper confidence limit (hardmshilim)
268-285 F18.15 --- PI ?=- Photon index (Photon_Index) (G5)
287-304 F18.15 --- b_PI ?=- Photon index lower limit
(PhotonIndexmin)
306-323 F18.15 --- B_PI ?=- Photon index upper limit
(PhotonIndexmax)
325-342 F18.15 [10-7W] logLX ?=- X-ray luminosity (Log (X-ray_Lum)) (G2)
344-361 F18.15 [10-7W] b_logLX ?=- X-ray luminosity lower value
(Log (X-rayLumlolim))
363-380 F18.15 [10-7W] B_logLX ?=- X-ray luminosity upper value
(Log (X-rayLumhilim))
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Byte-by-byte Description of file: rlq_csc2.dat rqq_csc2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 34 A34 --- SpName Spectral file name (SPECTRAL_NAME)
36- 51 F16.14 --- PI Photon index (PHOTON_INDEX)
53- 70 F18.15 --- E_PI [] Photon index error upper value
(PHOTONINDEXMIN)
72- 89 F18.15 --- e_PI Photon index error lower value
(PHOTONINDEXMAX)
91-106 F16.14 --- z Quasars redshift from CSC2 catalog (REDSHIFT)
108-114 F7.5 --- gammaCSC2 CSC2 photon index (Gamma_CSC2)
116-121 F6.4 --- b_gammaCSC2 CSC2 photon index error 68% lower confidence
limit (GammalolimCSC2)
123-128 F6.4 --- B_gammaCSC2 CSC2 photon index error 68% upper confidence
limit (GammahilimCSC2)
130-144 F15.11 deg RAdeg Right ascension (J2000) (ra)
146-160 F15.11 deg DEdeg Delcination (J2000) (dec)
162-182 A21 --- CXC CXC name (2CXO JHHMMSS.s+DDMMSS) (name)
184-188 I5 --- ObsID ?=- Observation identifier (obsid)
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Global notes:
Note (G1): ratio between the Radio flux at 6cm from FIRST survey, and
the optical flux at 2500Å from SDSS.
Note (G2): calculated X-ray luminosity, using the X-rays flux in in ACIS broad
band (0.5-7.0keV) and the redshift from DR7.
Note (G3): calculated X-ray luminosity low limit, using the X-ray flux low limit
in in ACIS broad band (0.5-7.0keV) and the redshift from DR7.
Note (G4): calculated X-ray luminosity high limit, using the X-ray flux high
limit in ACIS broad band (0.5-7.0keV) and the redshift from DR7.
Note (G5): calculated photon index, using powerlow and absorption model,
under wstat statistics.
Note (G6): high limit of calculated photon index, using powerlow and absorption
model, under wstat statistics.
Note (G7): low limit of the calculated photon index, using powerlow and
absorption model, under wstat statistics.
Note (G8): ACIS hard (2.0-7.0keV) - medium (1.2-2.0keV) energy band photon flux
hardness ratio.
Note (G9): ACIS hard (2.0-7.0keV) - soft (0.5-1.2keV) energy band photon flux
hardness ratio.
Note (G10): ACIS medium (1.2-2.0keV) - soft (0.5-1.2keV) energy band photon
flux hardness ratio.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 01-Jul-2024