Download - Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color
![Page 1: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/1.jpg)
Swift/BAT Hard X-ray Survey
Preliminary results in Markwardt et al 2005
35'
energy coded color
![Page 2: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/2.jpg)
BAT Instrument Parameters
• Energy Range 14 - 195 keV• Area 5200 cm2 (x 50% open fraction)• Field of View 2 Steradian, partially coded• Background 10,000 ct/s (cosmic diffuse
dominated)• Spatial 21’ sky pixel, centroided to <1-3’
Resolution• Spectral 6 keV FWHM @ 60 keV, average
Resolution• Sensitivity 0.2 photons/cm2/sec• Timing Resolution 100 usec• Observing “Random” (piggy-back Swift
Strategy GRB observing plan)
![Page 3: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/3.jpg)
9-month Swift/BAT Survey> 1.5 Ms
1-1.5 Ms
0.5-1 Ms
Eclip
tic P
lane
8.5 mCrab (T/20 ks)-0.5
Exposure Map• Covers whole sky, mostly >1Ms• deficit on Ecliptic Plane due to
Sun avoidance• Sensitivity improves as square
root of time (1.2-2 X statistical) to 0.6 milliCrab in 3 years
Sensitivityvs Time
![Page 4: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/4.jpg)
9 months---------------------• 323 sources• 39 unidentified
sources• 158 galactic• 5 galaxy clusters• 158 AGN
• 16 beamed
|Galactic b| >15 (74%)----------------------• 159 sources• 9 unidentified sources• 29 galactic• 2 galaxy clusters• 121 AGN
• 15 beamed
already the most sensitive all-sky hard x-ray surveyAt 3 years expect 450 AGN.
BAT Source Detections
![Page 5: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/5.jpg)
BAT GALAXY Identifications
• 70% of the galaxies with no Sy classification are absorbed.• Most unknown galaxies are absorbed Sy2's or edge on spiral
galaxies with no lines (3 with no spectroscopy)• Sy2/Sy1 ratio is 1.2 (0.5 Sy1.5/Sy1) and 52% of Seyfert
galaxies are absorbed confirming Markwardt et al 2005 Much lower than 75% predicted by the standard model for the CXB
absorbed Log nH > 22|Gal b| >15
abs unabs total
Sy1 3 31 34
Sy1.5 5 11 16
Sy2 36 3 40
no Sy ID 9 4 13
total 53 49 103
![Page 6: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/6.jpg)
Correlations of BAT Rate with other Bands
• no correlation between BAT and ROSAT count rates
• 44 BAT sources not detected by ROSAT
• no close correlation with total 2MASS J band
• soft x-ray and IR do not measure true AGN luminosity or complete populations
![Page 7: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/7.jpg)
BATXMM peaks at
20 keV
• >25% of BAT sources
have weak soft X-ray emission
• only a survey at >20 keV is unbiased by absorption
• Many have extremely complex spectra with soft and hard components that seem unrelated
• Simultaneous X-ray and hard X-ray spectra are required to understand AGN
Heavily Absorbed and Complex Spectra Abound
![Page 8: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/8.jpg)
LogN/LogS and Luminosity Function• errors 25% in normalization,
~10% in slopes and <1% in break luminosity
• New, much tighter constraints will test CXB models
• Treister, Urry, and Lira: standard unified AGN model 2500 AGN, LBAT>10-11ergs cm-2 s-1
• BAT measures 1100 AGN, LBAT>10-11ergs cm-2 s-1
• Pashak Ghandi800 AGN, LBAT>10-11ergs cm-2 s-1
![Page 9: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/9.jpg)
Average BAT AGN Spectrum
• no evidence for a break below 200 keV
• same with brightest 36 AGN removed
• Same for luminosity <1044 or >1044
• Contrast with strong break at 40 keV in CXB
• spectrum is much flatter than CXB (slope = 2.75) above the break
Crab NormalizedResponse
![Page 10: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/10.jpg)
E-2
Background vs BAT AGN Spectrum• BAT AGN
spectrum is a bad fit to CXB for E>40 keV
• Soft x-ray surveys put source of CXB at Z=0.7
• to fit the CXB the BAT AGN must be at Z > 1 or show strong spectral evolution
150 keVBAT UL
![Page 11: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/11.jpg)
What is the Blazar Contribution to the CXB?
• BAT beamed sum spectrum is 10-16% AGN sum
• In 3 years, BAT will detect >40 beamed sources.
• BAT survey can answer this question.
Beamed Sources
Beamed Fraction
![Page 12: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/12.jpg)
Conclusions• The first complete AGN survey is answering many of
the old questions about AGN and their contribution to the CXB.– What are the numbers of hard x-ray AGN?
• 1100 AGN, LBAT>10-11ergs cm-2 s-1 14-200 keV
– Are the hard x-ray AGN and CXB spectra the same? No– Does the standard unified model explain all? No– How many of the AGN are absorbed? ~0.6 not 3/4– What is the blazar contribution to CXB? 10-15%
• Follow up of the BAT selected AGN offers many exciting new opportunities.
We are just getting started!
![Page 13: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/13.jpg)
BACKUP SLIDES
![Page 14: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/14.jpg)
BAT Survey Characteristics• survey sensitivity is still improving
as the square root of time• a longer survey detects more
sources but it also makes better spectra for the previous sources
• 4 energy bands will be expanded to 8 bands soon
• extragalactic BAT sources are easily to identify at high latitudes– very bright IR galaxy– low redshift (z<0.06)– optical AGN or high absorption
• XRT positions and joint XRT/BAT spectra make ID's unambiguous
8.5 mCrab (T/20 ks)-0.5
XRTUVOTBATjointspectra
BATXRT
Sensitivity vs. Exposure
![Page 15: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/15.jpg)
Tests of the Standard Model
• BAT selected Sy1's have higher luminosity than Sy2's (3.6)
• differences are small, so no selection effect for BAT
With <E>~50 kev BAT measures the true nature of the continuum relatively unaffected by absorption or scattering
• BAT selected Sy1's have softer spectra than Sy2's (5.7)
![Page 16: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/16.jpg)
Absorption's Effect on Luminosity Function• more high luminosity with
NH<22 and more low luminosity NH>22
• more statistics required• the Swift/BAT survey will
get there
![Page 17: Swift/BAT Hard X-ray Survey Preliminary results in Markwardt et al 2005 35' energy coded color](https://reader035.vdocuments.site/reader035/viewer/2022062320/56649d2b5503460f94a00460/html5/thumbnails/17.jpg)
Swift/BAT and Integral luminosity functions• the INTEGRAL and
Swift/BAT luminosity functions are in rough agreement
• The Sazanov data seems to be systematically higher