Max-Planck-Institut für extraterrestrische Physik Simulating the eROSITA sky: exposure, sensitivity, and data reduction Hermann Brunner 1 , Thomas Boller 1 , Marcella Brusa 1 , Fabrizia Guglielmetti 1 , Christoph Grossberger 2 , Ingo Kreykenbohm 2 , Georg Lamer 3 , Florian Pacaud 4 , Jan Robrade 5 , Christian Schmid 2 , Francesco Pace 6 , Mauro Roncarelli 7 For further information, please contact: [email protected] Simulating the eROSITA sky eROSITA on SRG eROSITA orbit and scanning strategy Data reduction and catalogue creation All-sky survey sensitivity average survey exposure: 2 ks (80% observing efficiency) Effective area Averaged all-sky survey PSF (examples) on axis 15´ off-axis 30´off-axis 1 keV 4 keV 7 keV Ray-tracing PSF Field-of-view averaged effective area at 1.5 keV is ~1500 cm 2 for XMM-Newton and eROSITA. Field-of-view of eROSITA is four times XMM-Newton. a Grasp is four times XMM-Newton. On-axis PSF has 15´´ HEW for XMM-Newton and eROSITA. But field-averaged eROSITA PSF (25´´-30´´ HEW) is twice XMM-Newton. X-ray flux light-cones from hydrodynamical N-body simulations Roncarelli et al. 2006 Pace et al. 2008 + point sources from extragal. logN–logS + particle + instrumental + soft X-ray background folded with eROSITA PSF 3.6 o x 3.6 o eROSITA all-sky survey field source content of four year all-sky survey: 50-100 thousand clusters, hundreds with z>1 ~3 Mill. AGN 30-100 z>6 AGN Exposure time [s] Comparison XMM-Newton - eROSITA To achieve same soft band sensitivity, 10 ks of XMM-Newton exposure time corresponds to about 15 ks of eROSITA time. eROSITA (extended Roentgen Survey with an Imaging Telescope Array) is the primary instrument on the Russian Spektrum-Roentgen-Gamma (SRG) mission, scheduled for launch in 2013. eROSITA consists of seven Wolter-I telescope modules, each of which is equipped with 54 mirror shells with an outer diameter of 36 cm and a fast frame-store pn-CCD, resulting in a field-of-view (1 o diameter) averaged PSF of 25´´-30´´ HEW (on-axis: 15´´ HEW) and an effective area of 1500 cm 2 at 1.5 keV. eROSITA/SRG will perform a four year long all-sky survey, to be followed be several years of pointed observations (Predehl et al. 2010). Orbit: eROSITA/SRG will be placed in an L2 orbit with a semi-major axis of about 1 million km and an orbital period of about 6 months. Survey scanning law: during the four year all-sky survey, the eROSITA tele- scopes will scan the sky in great circles with one full circle being completed every four hours. The scan axis is either pointed directly towards the sun or alternatively up to several degrees away from it. As the satellite moves around the Sun, the plane of the scan is ad- vanced by about 1 o per day, resulting in a full coverage of the sky every half year. All-sky survey exposure: After four years (eight full scans of the sky), a minimum exposure of 1.3 ks (at the ecliptic equator) and a mean exposure of 2.0 ks is achieved (assuming 80% observing efficiency) . The exposure close to the ecliptic poles can be opti- mized by appropriately choosing the offset-angles of the scan axis from the sun direction (details tbd). Examples: 100 deg 2 around each pole, covered with an exposure of at least 15 ks (red symbols on the right ), or alternatively 250 deg 2 with an exposure above 10 ks (blue symbols). w w w w sun pointing sun pointing offset pointing offset pointing offset pointing offset pointing eROSITA data analysis pipeline Software derived from ROSAT, Abrixas, XMM-Newton + newly developed code Compiler: F90/GFortran (for compatibility with exiting code) CFITSIO for file i/o CALDB calibration interface PIL (FTOOLS) command line interface Same programs for pipeline processing and interactive analysis 15 FTE forseen for software development - 50% done K. Dennerl Survey II Concept Sky is devided into 5839 equal area fields of ~3 o x3 o After event-calibration, incoming data stream is split and accumulated in same number of overlapping 3.6 o x3.6 o all-sky survey maps, centred on these fields. Source detection and further souce-level analysis is performed on these maps. overlap area unique area (sky map 60) sky map Source detection and characterization Performed simultaneously in five energy bands (baseline: E min -0.5, 0.5-1, 1-2, 2-4, 4-8 keV - details tbd) Several different detection algorithms – ongoing simulations to determine specific setup of detection pipeline (see example on the right) box detection with local background spline fit of source free area box detection with spline background Max. Likelihood PSF & extent fits Bayesian backgr.- source separation Wavelet detection validation, source matching, catalogue insertion ? ? Guglielmetti et al. 2009 + separate poster References: N. Cappelluti et al., 2009, A&A, 497, 635 F. Guglielmetti et al., 2009, MNRAS, 396, 165-190 F. Pace et al., 2008, A&A, 483, 389 P. Predehl et al., 2010, SPIE, 7732, 77320U M. Roncarelli et al., 2006, MNRAS, 348. 1078 1 Max-Planck-Institut für extraterrestrische Physik, Garching, 2 Dr. Karl Remeis-Sternwarte und ECAP, 3 Leibniz-Institut für Astrophysik, Potsdam, 4 Argelander-Institut für Astronomie, 5 Hamburger Sternwarte, 6 Institute of Cosmology & Gravitation, University of Portsmouth, 7 Dipartimento di Astronomico, Università di Bologna detection pipeline simulation input catalogues (clusters, AGN) catalogue of detected sources simulated images ? 1 keV 4 keV 7 keV 0´ 15´ 30´ max. survey exposure: 20 ks (80% observing efficiency) Download this poster here: http://www.xray.mpe.mpg.de/~hbrunner/Garmisch2011Poster.pdf More info on eROSITA: http://www.mpe.mpg.de/erosita/ scan axis pointed at sun t offset-angles 0.2 o 0.7 o 1.2 o 1.7 o t offset-angles 1.0 o 2.8 o 4.8 o 7.0 o t The scan axis will be pointed at each offset-angle for one full year, causing the scan poles to ‘pre- cess‘ around the ecliptic poles with these offsets. Cappelluti et al. 2009 First eROSITA International Conference, Garmisch-Partenkirchen 2011 Point source detection sensitivity Background on-axis effective area (cm 2 ) counts s -1 keV -1 arcmin -2 Energy (keV) Energy (keV)
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Max-Planck-Institut für extraterrestrische Physik
Simulating the eROSITA sky: exposure,
sensitivity, and data reduction Hermann Brunner1, Thomas Boller1, Marcella Brusa1, Fabrizia Guglielmetti1, Christoph Grossberger2, Ingo
Kreykenbohm2, Georg Lamer3, Florian Pacaud4, Jan Robrade5, Christian Schmid2, Francesco Pace6, Mauro Roncarelli7
For further information, please contact: [email protected]
Simulating the eROSITA sky
eROSITA on SRG
eROSITA orbit and scanning strategy
Data reduction and catalogue creation
All-sky survey sensitivity
average survey exposure: 2 ks (80% observing efficiency)
Effective area
Averaged all-sky survey PSF (examples)
on axis 15´ off-axis 30´off-axis
1 keV
4 keV
7 keV
Ray-tracing PSF
Field-of-view averaged effective area at 1.5 keV is ~1500 cm2 for XMM-Newton and eROSITA.
Field-of-view of eROSITA is four times XMM-Newton. a Grasp is four times XMM-Newton.
On-axis PSF has 15´´ HEW for XMM-Newton and eROSITA. But field-averaged eROSITA PSF
(25´´-30´´ HEW) is twice XMM-Newton.
X-ray flux light-cones
from hydrodynamical
N-body simulations Roncarelli et al. 2006
Pace et al. 2008
+ point sources from
extragal. logN–logS
+ particle + instrumental
+ soft X-ray background
folded with eROSITA PSF
3.6o x 3.6o eROSITA
all-sky survey field
source content of four year
all-sky survey:
50-100 thousand
clusters, hundreds with z>1
~3 Mill. AGN
30-100 z>6 AGN
Exposure time [s]
Comparison XMM-Newton - eROSITA
To achieve same soft band sensitivity, 10 ks of XMM-Newton
exposure time corresponds to about 15 ks of eROSITA time.
eROSITA (extended Roentgen Survey with an Imaging Telescope Array) is the primary instrument on the
Russian Spektrum-Roentgen-Gamma (SRG) mission, scheduled for launch in 2013. eROSITA consists of
seven Wolter-I telescope modules, each of which is equipped with 54 mirror shells with an outer diameter
of 36 cm and a fast frame-store pn-CCD, resulting in a field-of-view (1o diameter) averaged PSF of 25´´-30´´
HEW (on-axis: 15´´ HEW) and an effective area of 1500 cm2 at 1.5 keV. eROSITA/SRG will perform a four
year long all-sky survey, to be followed be several years of pointed observations (Predehl et al. 2010).
Orbit: eROSITA/SRG will be placed in an
L2 orbit with a semi-major axis of about
1 million km and an orbital period of
about 6 months.
Survey scanning law: during the four
year all-sky survey, the eROSITA tele-
scopes will scan the sky in great circles
with one full circle being completed
every four hours. The scan axis is either
pointed directly towards the sun or
alternatively up to several degrees away
from it. As the satellite moves around
the Sun, the plane of the scan is ad-
vanced by about 1o per day, resulting in
a full coverage of the sky every half year.
All-sky survey exposure: After four years (eight full scans of the
sky), a minimum exposure of 1.3 ks (at the ecliptic equator) and a
mean exposure of 2.0 ks is achieved (assuming 80% observing
efficiency) . The exposure close to the ecliptic poles can be opti-
mized by appropriately choosing the offset-angles of the scan
axis from the sun direction (details tbd). Examples: 100 deg2
around each pole, covered with an exposure of at least 15 ks (red
symbols on the right ), or alternatively 250 deg2 with an exposure
above 10 ks (blue symbols).
w
w w
w
sun pointing sun pointing
offset pointing offset pointing
offset pointing offset pointing
eROSITA data analysis pipeline
Software derived from ROSAT,
Abrixas, XMM-Newton + newly
developed code
Compiler: F90/GFortran (for
compatibility with exiting code)
CFITSIO for file i/o
CALDB calibration interface
PIL (FTOOLS) command line
interface
Same programs for pipeline
processing and interactive
analysis
15 FTE forseen for software
development - 50% done
K. Dennerl
Survey II Concept
Sky is devided into 5839 equal area fields of ~3ox3o
After event-calibration, incoming data stream is split
and accumulated in same number of overlapping
3.6ox3.6o all-sky survey maps, centred on these fields.
Source detection and further souce-level analysis is
performed on these maps.
overlap
area unique area
(sky map 60)
sky map
Source detection and characterization
Performed simultaneously in five energy bands
(baseline: Emin-0.5, 0.5-1, 1-2, 2-4, 4-8 keV - details tbd)
Several different detection algorithms – ongoing
simulations to determine specific setup of detection
pipeline (see example on the right)
box detection with
local background
spline fit of
source free area
box detection with
spline background
Max. Likelihood
PSF & extent fits
Bayesian backgr.-
source separation
Wavelet
detection
validation, source matching, catalogue insertion
? ?
Guglielmetti et al. 2009
+ separate poster
References:
N. Cappelluti et al., 2009, A&A, 497, 635
F. Guglielmetti et al., 2009, MNRAS, 396, 165-190
F. Pace et al., 2008, A&A, 483, 389
P. Predehl et al., 2010, SPIE, 7732, 77320U
M. Roncarelli et al., 2006, MNRAS, 348. 1078
1Max-Planck-Institut für extraterrestrische Physik, Garching, 2Dr. Karl Remeis-Sternwarte und ECAP, 3Leibniz-Institut für Astrophysik, Potsdam, 4Argelander-Institut
für Astronomie, 5Hamburger Sternwarte, 6Institute of Cosmology & Gravitation, University of Portsmouth, 7Dipartimento di Astronomico, Università di Bologna
detection
pipeline
simulation input catalogues
(clusters, AGN)
catalogue of
detected sources
simulated images
?
1 keV
4 keV
7 keV 0´ 15´ 30´
max. survey exposure: 20 ks (80% observing efficiency)
Download this poster here: http://www.xray.mpe.mpg.de/~hbrunner/Garmisch2011Poster.pdf
More info on eROSITA: http://www.mpe.mpg.de/erosita/
scan axis pointed at sun t
offset-angles 0.2o 0.7o 1.2o 1.7o t
offset-angles 1.0o 2.8o 4.8o 7.0o t
The scan axis will be pointed at each offset-angle
for one full year, causing the scan poles to ‘pre-
cess‘ around the ecliptic poles with these offsets.
Cappelluti et al. 2009
First eROSITA International Conference, Garmisch-Partenkirchen 2011
Point source detection sensitivity
Background
on-a
xis
eff
ecti
ve
area
(cm
2)
counts
s-1
keV
-1 a
rcm
in-2
Energy (keV) Energy (keV)
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