J/AJ/162/254 Concordance fluxes; calibration X-Ray telescopes (Marshall+, 2021)
Concordance: in-flight calibration of X-ray telescopes without absolute
references.
Marshall H.L., Chen Y., Drake J.J., Guainazzi M., Kashyap V.L., Meng X.-L.,
Plucinsky P.P., Ratzlaff P., Van Dyk D.A., Wang X.
<Astron. J., 162, 254-254 (2021)>
=2021AJ....162..254M 2021AJ....162..254M (SIMBAD/NED BibCode)
ADC_Keywords: X-ray sources
Keywords: Flux calibration; Astronomical methods; X-ray astronomy; Calibration
Abstract:
We describe a process for cross-calibrating the effective areas of
X-ray telescopes that observe common targets. The targets are not
assumed to be "standard candles" in the classic sense, in that we
assume that the source fluxes have well-defined, but a priori unknown
values. Using a technique developed by Chen et al. that involves a
statistical method called shrinkage estimation, we determine effective
area correction factors for each instrument that bring estimated
fluxes into the best agreement, consistent with prior knowledge of
their effective areas. We expand the technique to allow unique priors
on systematic uncertainties in effective areas for each X-ray
astronomy instrument and to allow correlations between effective areas
in different energy bands. We demonstrate the method with several data
sets from various X-ray telescopes.
Description:
We select a sample of X-ray sources from the Second European Photon
Imaging Camera (EPIC) Serendipitous Source (2XMM) Catalog. EPIC
consists of three X-ray cameras with CCD sensors mounted on the ESA
spacecraft XMM-Newton; the EPIC-pn and two EPIC-MOS cameras observe
celestial sources quasi-simultaneously within their co-aligned fields
of view.
Another set of EPIC spectra used to validate the model is the XCAL
sample. This is a sample of radio-loud active galactic nuclei,
primarily blazars, observed routinely by XMM-Newton in the framework
of its in-flight calibration program. In this case, there are more
blazars and high signal observations, for a total of 108, 103, and 94
observations of 22 distinct sources in the soft, medium, and hard
bands that exceeded a flux limit criterion without highly discrepant
fluxes between the three instruments.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 78 429 Concordance fluxes
tablea2.dat 76 158 Capella grating observations with Chandra
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See also:
IX/50 : XMM-Newton Serendipitous Source Catalogue 3XMM-DR6 (XMM-SSC, 2016)
IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)
J/A+A/575/A30 : HIFLUGCS XMM/Chandra cross-calibration (Schellenberger+, 2015)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Target Target identifier
17- 20 A4 --- Sample Sample (1)
22- 27 A6 --- Band Band; hard, medium or soft
29- 36 F8.6 ph/cm2/s FluxN [0.0007/0.14] Flux normalization
38- 43 F6.4 --- Flux1 [0.0008/1] pn Flux
45- 50 F6.4 --- e_Flux1 [0/0.9] Uncertainty in Flux1
52- 57 F6.4 --- Flux2 [0.0008/1] MOS1 Flux
59- 64 F6.4 --- e_Flux2 [0/0.8] Uncertainty in Flux2
66- 71 F6.4 --- Flux3 [0.0008/1] MOS2 Flux
73- 78 F6.4 --- e_Flux3 [0/0.9] Uncertainy in Flux3
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Note (1): Sample as follows:
2XMM = Sample of X-ray sources from the 2nd European Photon Imaging Camera
(EPIC) Serendipitous Source (2XMM) Catalog
(Watson+, 2009, J/A+A/493/339)
XCAL = active galaxies in the XMM-Newton Cross-Calibration (XCAL) sample.
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Epoch [1/21] Epoch Group
4- 6 A3 "month" Obs.M Epoch, Month
8- 11 I4 yr Obs.Y [1999/2018] Epoch, Year
13- 17 I5 --- ObsID [57/62435] Chandra Observation ID
19- 23 F5.2 ks Exp [9.42/59.2] Exposure time
25- 30 A6 --- Detector Detector; ACIS-S or HRC-S
32- 36 A5 --- Grating Grating Arm
38- 41 F4.1 10-16W/m2 NeXlb12 [16.5/43]? Line Flux, Ne X 12.13A,
10-13erg/s/cm2
43- 45 F3.1 10-16W/m2 e_NeXlb12 [0.6/5]? Uncertainty in NeXlb12
47- 50 F4.1 10-16W/m2 FeXVIIlb15 [39.3/90.1]? Line Flux, Fe XVII 15.02A,
10-13erg/s/cm2
52- 55 F4.1 10-16W/m2 e_FeXVIIlb15 [0.8/14]? Uncertainty in FeXVIIlb15
57- 61 F5.1 10-16W/m2 FeXVIIlb17 [38.7/116]? Line Flux,Fe XVII 17.05A,
10-13erg/s/cm2
63- 66 F4.1 10-16W/m2 e_FeXVIIlb17 [0.9/24]? Uncertainty in FeXVIIlb17
68- 71 F4.1 10-16W/m2 OVIIIlb19 [19.7/56.5]? Line Flux, O VIII 18.96A,
10-13erg/s/cm2
73- 76 F4.1 10-16W/m2 e_OVIIIlb19 [0.7/18]? Uncertainty in OVIIIlb19
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 21-Feb-2022