Transcript HD 210803
A Narrow Band EUV search for Background Objects with the AIA Sam Schonfeld Advisors: Paola Testa and Steve Saar Contents Motivation Cross calibrating solar measurements Methods: Finding Targets Tracking targets Modeling stellar emission Estimating Signal AIA 171Å Methods: Preparing Observations Off-Limb Intensity Decay Satellite Path Correction Conclusions AIA 193Å Motivation: Comparing Sun and Stars Sun is a Star at 1 AU Spatial resolution Test stellar models This proximity is also a problem Difficult to measure the Sun and anything else with the same instrument ○ Different telescopes use different techniques ○ Possible discrepancies between instruments Motivation: The AIA Constant full sun imaging from SDO Narrow band EUV telescopes High resolution and cadence Chance to observe Sun and stars together Objectives: Primary: Determine whether possible to observe background objects Secondary: If possible, make observations Methods: Can AIA Detect Stars? Cons Pros Star is > 107 farther ○ Flux=L / (4πD2) Star is point a source Extinction due to ISM AIA is sensitive ○ Dynamic range ≈ 104 DN Sun is relatively dim Object must be ≈103 more Luminous than Sun! Methods: Candidate Objects Selected from ROSAT x-ray observations Stars Quasar/AGN/Galaxy Galaxy Cluster Unknown HD 199143 QSO J2137-1432 Abell 2426 J080311.1+202213 HD 206301 Pks 2349-014 Abell 193 J084029.9+182417 HD 210803 LEDA 1510700 Abell 763 J154426.3-201637 HD 15814 QSO B0317+183 J171209.5-231005 HD 244354 LEDA 97068 J171227.5-232140 HD 245358 LEDA 23927 J180037.6-232454 HD 245924 2MASX J12401929- 0349194 Flare Star J180824.5-230917 HD 58728 3C 279 GJ 4282 J182928.2-234743 HD 130819 Methods: Path Elimination 1 pixel ≈ 0.6 arc seconds Methods: Remaining Objects Stars Quasar/AGN/Galaxy Galaxy Cluster Unknown HD 199143 QSO J2137-1432 Abell 2426 J080311.1+202213 HD 206301 Pks 2349-014 Abell 193 J084029.9+182417 HD 210803 LEDA 1510700 Abell 763 J154426.3-201637 HD 15814 QSO B0317+183 J171209.5-231005 HD 244354 LEDA 97068 J171227.5-232140 HD 245358 LEDA 23927 J180037.6-232454 HD 245924 J12401929- 0349194 Flare Star J180824.5-230917 HD 58728 3C 279 GJ 4282 J182928.2-234743 HD 130819 4 Stars, 3 Galaxies, 2 Galaxy Clusters, 2 Unknown Methods: Stellar EM Models Emission Measure PZ Tel EM DEM (T ) P (T ) dT Differential Emission Measure ○ Amount of emitting Argiroffi et al. 2004 material P(T)=emissivity Use models of similar stars Scale with distance and luminosity AIA Temperature response functions Based on atomic models 94 131 171 193 211 335 Methods: Predicted Count Rates hd 206301 Count Rate (DN/s/pix) 1 hd 210803 hd 245924 0.1 hd 199143 0.01 AIA exposure ≈ 2.9 sec 0.001 0.0001 94 131 171 Wavelength Å 193 211 335 Methods: Observational Techniques AIA 171Å Track Single pixel across field for hours Integrate signal ○ Acts like a longer exposure Takes advantage of point source Subtract out background Off-limb coronal emissions Methods: Off-limb Coronal Emission AIA 171Å Methods: Exponential Decay 171 Å Consistent with exponential decay of coronal density 94 Å Suggests AIA noise ≈3 DN Methods: Image Offset Problem SDO is in Orbit! Earth Geostationary Geosynchronous Corrected Earth Geostationary Geosynchronous Corrected April 2011 Dr. Bart De Pontieu June 2010 Conclusion Observation appears possible but… Stellar sources produce count rates within the noise level Future Work: to make observations Finish orbit corrections Longer exposures would allow observations Off pointing from disk would increase number of targets Include non-stellar targets Supplemental HD 199143 PMS AeFe HD 206301 Variable RS CVn type HD 210803 PMS HD 245924 T-Tau type