1. The Variable Source Content of the The Variable Source Content of the
2XMM Catalogue
The Variable Source Content of the
2XMM Catalogue
Sean Farrell
Natalie Webb, Didier Barret, David Villa-Pascual, Joana Rodrigues
Centre d’Etude Spatiale des Rayonnements
Toulouse, France
Andrew Gosling
University of Oulu
Oulu, Finland

2. Overview Overview The 2XMM catalogue – a brief introduction
Determining the nature of the variable sources
Statistical breakdown
Preliminary population studies
Some highlights
Conclusions

3. The 2XMM Catalogue The 2XMM Serendipitous Source Catalogue
Largest X-ray catalogue ever produced, containing:
246,897 source detections
38,320 detections with light curves / spectra
2,307 detections flagged as variable
191,870 unique sources
2,001 unique variable sources

4. Determining the Nature
Determining the nature of the variable sources
Manually inspected images, lightcurves & spectra for all 2,001 discrete variable sources
Spurious sources identified from images
Performed a search in SIMBAD around coordinates of real sources
Attempted to determine nature of previously identified sources through SIMBAD and literature search
Optical
loading
OOT
event
Wings of
bright src

5. Statistics Serendipitous Targets TOTAL Planets (Saturn) - < 1%
Serendipitous
Targets
TOTAL
Planets (Saturn) -
< 1%
AXPs/SGRs
Pulsars
Neutron Stars
ULX
SNR 1%
GRB 3%
SSS
Extended Emission
X-ray binaries 2%
14% 4%
CVs
28%
AGN
24% 5%
Unknown
21%
Stars
23%
Spurious
47%
41%
100%

6. Breakdown of spurious sources
Statistics
Breakdown of spurious sources
All spurious sources flagged as “good” due to optical loading from a very bright star in the field
Remaining spurious sources picked up by pipeline
Source Quality
SUM_FLAG %
Good
< 1%
Source parameters may be affected 1 0%
Possibly spurious 2
In area where spurious detections may occur 3
50%
In area where spurious detections may occur and possibly spurious 4
100%

7. Population Studies All 2XMM Sources LMC SMC Gal cluster Taurus MC
Orion Neb

8. Population Studies Variable 2XMM Sources LMC SMC Gal cluster Taurus MC
Orion Neb

9. Population Studies

10. Population Studies
AGN
Unknown
XRBs
CVs
SSS
Stars

11. Population Studies
Compact Objects

12. Highlights 2.2 hr period Pow / brem spectrum Faint XRB or CV?
BB / nsatmos spectrum
Quiescent NS XRB?
2.1 hr period
Pow / brem spectrum
AM Her CV?

13. Highlights 1.2 hr period Brem spectrum CV? 1.6 hr period
Pow / brem spectrum
XRB or CV?
627 s period
Cut-off pow spectrum
Long-period pulsar

14. Highlights 237 s 237 s period Power law spectrum
>8 NIR counterparts, 1 very blue
Another long-period pulsar?
237 s

15. Conclusions Conclusions
~41% variable sources spurious, vast majority picked up by pipeline
~38% real sources unknown, ~37% stars, remaining sources mostly compact objects (AGN, CVs, XRBs)
New populations of faint sources emerging, providing insight into X-ray emission over wider range of luminosities
2XMM catalogue is a powerful resource for population studies of all kinds of objects

16. Thanks for your attention
Questions?
Thanks for your attention
Gratuitous poster plug…
Soft X-ray Sources in the 2XMM Catalogue
Rodrigues, Farrell, Webb & Barret
Poster D.10