J/ApJ/914/130 Chandra & VLA obs. of 14 high-redshift QSOs (Snios+, 2021)
Discovery of candidate X-ray jets in high-redshift quasars.
Snios B., Schwartz D.A., Siemiginowska A., Sobolewska M., Birkinshaw M.,
Cheung C.C., Gobeille D.B., Marshall H.L., Migliori G., Wardle J.F.C.,
Worrall D.M.
<Astrophys. J., 914, 130 (2021)>
=2021ApJ...914..130S 2021ApJ...914..130S
ADC_Keywords: QSOs; Redshifts; X-ray sources; Radio lines; Optical
Keywords: Active galactic nuclei ; X-ray active galactic nuclei ;
High-redshift galaxies ; Jets ; High energy astrophysics
Abstract:
We present Chandra X-ray observations of 14 radio-loud quasars at
redshifts 3<z<4, selected from a well-defined sample. All quasars are
detected in the 0.5-7.0keV energy band, and resolved X-ray features
are detected in five of the objects at distances of 1"-12" from the
quasar core. The X-ray features are spatially coincident with known
radio features for four of the five quasars. This indicates that these
systems contain X-ray jets. X-ray fluxes and luminosities are
measured, and jet-to-core X-ray flux ratios are estimated. The flux
ratios are consistent with those observed for nearby jet systems,
suggesting that the observed X-ray emission mechanism is independent
of redshift. For quasars with undetected jets, an upper limit on the
average X-ray jet intensity is estimated using a stacked image
analysis. Emission spectra of the quasar cores are extracted and
modeled to obtain best-fit photon indices, and an Fe K emission line
is detected from one quasar in our sample. We compare X-ray spectral
properties with optical and radio emission in the context of both our
sample and other quasar surveys.
Description:
Each target selected for our survey was observed with Chandra using
the Advanced CCD Imaging Spectrometer (ACIS) with the aimpoint
centered on the S3 chip. Details on our Chandra observations (spanning
2018-Jan-19 to 2019-Mar-10) are provided in Table 1.
In addition to the X-ray data, radio observations of the sample were
included in our analysis. We obtained new Karl G. Jansky Very Large
Array (VLA) A-array observations of these 14 quasars (see Table 2 for
a summary) as part of a more extensive radio imaging and follow-up
program of this sample (Gobeille+ 2014arXiv1406.4797G 2014arXiv1406.4797G). The majority
of the VLA maps (13/14) were obtained as single ∼4-6 minute snapshot
observations in November 2012 (program 12B-230) using two 1GHz wide
intermediate-frequency bands centered at 4.9 and 7.4GHz (effective
center frequency of 6.2GHz). For J0833+0959, we used an earlier VLA
A-array 1.4GHz map we obtained in October 2008 (program AW748) and
published in Gobeille+ (2014arXiv1406.4797G 2014arXiv1406.4797G).
We also have compiled optical properties of our sample in an effort to
investigate the optical and X-ray relationship among our sources.
In keeping with our previous quasar analysis (Snios+ 2020ApJ...899..127S 2020ApJ...899..127S),
we obtained optical fluxes at the rest-frame wavelength of 1450Å.
For our current sample, this corresponds to observed wavelengths
between 5850-7000Å. We consequently utilized the monochromatic AB
apparent magnitude from the Pan-STARRS r band as it has an effective
wavelength of 6241Å. See Section 6.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 87 14 Chandra observations of the quasar sample
table2.dat 53 14 VLA observations of quasar sample
table4.dat 42 168 X-ray morphological analysis of quasar sample
table6.dat 37 14 Optical properties of the quasar sample
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
VIII/90 : The FIRST Survey Catalog, Version 12Feb16 (Becker+ 2012)
VII/286 : SDSS quasar catalog, fourteenth data release (Paris+, 2018)
VII/289 : SDSS quasar catalog, sixteenth data release (DR16Q) (Lyke+, 2020)
J/ApJS/92/53 : Einstein database of quasars. I. (Wilkes+, 1994)
J/ApJ/626/95 : Gamma-ray blazar candidates (Sowards-Emmerd+, 2005)
J/ApJ/657/116 : X-ray and UV parameters of radio-quiet quasars (Kelly+, 2007)
J/ApJ/750/99 : The Pan-STARRS1 photometric system (Tonry+, 2012)
J/ApJ/819/62 : The COSMOS-Legacy Survey (CLS) catalog (Civano+, 2016)
J/ApJ/819/154 : SDSS-DR7 QSOs with X-ray and UV luminosities (Lusso+, 2016)
J/ApJS/249/17 : SDSS QSO DR14 spectral properties (Rakshit+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- QSO Quasar designation (JHHMM+DDMM)
12- 16 F5.3 --- z [3/3.81] Redshift measurements (1)
18- 19 I2 h RAh Hour of right ascension (J2000) (2)
21- 22 I2 min RAm Minute of right ascension (J2000)
24- 29 F6.3 s RAs Second of right ascension (J2000)
31 A1 --- DE- Sign of declination (J2000) (2)
32- 33 I2 deg DEd Degree of declination (J2000) (2)
35- 36 I2 arcmin DEm Arcminute of declination (J2000)
38- 42 F5.2 arcsec DEs Arcsecond of declination (J2000)
44- 48 I5 --- ObsID [20399/20412] Observation identifier (3)
50- 60 A11 "Y/M/D" Date Date of observation (UT)
62- 65 F4.2 ks Exp [9/9.8] Total exposure time after flare
removal reprocessing and dead time correction
67- 70 F4.2 [Msun] logMBH [8.53/9.99]? log of BH mass (4)
72- 75 F4.2 [Msun] e_logMBH [0.01/0.5]? logMBH uncertainty
77- 81 F5.2 [10-7W] logLbol [46.63/47.86]? Log of bolometric luminosity (4)
83- 87 F5.2 --- logLEdd [-0.77/0.34]? Eddington ratios for the quasar
sample
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Note (1): Redshift measurements from Sowards-Emmerd+ (2005, J/ApJ/626/95);
Husband+ (2015MNRAS.452.2388H 2015MNRAS.452.2388H), and Paris+ (2018, VII/286).
Note (2): Radio centroid coordinates from VLA positions reported in
Gobeille+ (2014arXiv1406.4797G 2014arXiv1406.4797G).
Note (3): Observations performed using Chandra ACIS-S instrument with the
aimpoint on the S3 chip.
Note (4): Measurements from Rakshit+ (2020, J/ApJS/249/17).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- QSO QSO identifier (JHHMM+DDMM)
12- 16 F5.1 s ExpVLA [259.2/580] VLA exposure time
18- 20 F3.1 GHz Freq [1.4/6.2] Observed frequency
22- 32 A11 "Y/M/D" DateVLA VLA observation date
34- 37 F4.2 arcsec maxBeam [0.24/1.95] Beam maximum
39- 42 F4.2 arcsec minBeam [0.21/1.41] Beam minimum
44- 48 F5.1 deg PABeam [-61.4/72.3] Beam position angle
50- 53 F4.2 mJy/beam Int [0.1/0.85] Minimum contour intensity
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- QSO Quasar identifier (JHHMM+DDMM)
12- 13 I2 --- Sec [1/12] Annulus sector
15- 17 F3.1 arcsec Inner [1/1.7] Inner annular radius of sector
19- 22 F4.1 arcsec Outer [2/11] Outer annular radius of sector
24- 25 I2 ct OCts [0/12] Observed 0.5-7.0keV counts in sector
27- 30 F4.2 ct PCts [0.14/6.1] Mean 0.5-7.0keV counts from
simulated PSF in sector
32- 35 F4.2 ct BCts [0.02/0.6] 0.5-7.0keV counts from field
background in sector
37- 42 F6.4 --- Prob [0/1] Cumulative Poisson probability of
detecting counts greater than observed counts (1)
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Note (1): A probability of 0.0000 indicates a value less than 0.0001
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- QSO Quasar identifier (JHHMM+DDMM)
12- 16 F5.2 mag m1450 [17.4/21.1] Rest-frame, monochromatic AB
apparent magnitude at 1450Å, as
measured from Pan-STARRS r band (5)
18- 21 F4.1 10+24W/Hz L2500 [2.3/54.7] Rest-frame, monochromatic
luminosity at 2500Å, in units of
1031erg/s/Hz
23- 27 F5.2 --- aOX [-1.86/-1.25] Optical-to-X-ray power-law
slope
29- 32 F4.2 --- e_aOX [0.03/0.14] Lower uncertainty on aOX (6)
34- 37 F4.2 --- E_aOX [0.03/0.13] Upper uncertainty on aOX (6)
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Note (5): Fluxes are assumed to have a 0.1mag uncertainty.
Note (6): αox errors include both optical and X-ray uncertainties.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Dec-2022