Post on 15-Jan-2016
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Systematic Detections of Starbursting Dwarf Galaxies
Michael MasedaMPIA
11/10/2011
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Photometric Selection
11/10/2011
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Detection of Sources
• Identify all point sources in grism image• Mask 0th order objects with HF140W < 22.5• Create extraction box in direct image around
candidates from grism image• Match sources within that box to objects in
master catalog• Visually inspect the extracted spectrum
11/10/2011
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Detection of Sources
• Identify all point sources in grism image• Mask 0th order objects with HF140W < 22.5• Create extraction box in direct image around
candidates from grism image• Match sources within that box to objects in
master catalog• Visually inspect the extracted spectrum
11/10/2011
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Detection of Sources
• Identify all point sources in grism image• Mask 0th order objects with HF140W < 22.5• Create extraction box in direct image around
candidates from grism image• Match sources within that box to objects in
master catalog• Visually inspect the extracted spectrum
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Detection of Sources
• Identify all point sources in grism image• Mask 0th order objects with HF140W < 22.5• Create extraction box in direct image around
candidates from grism image• Match sources within that box to objects in
master catalog• Visually inspect the extracted spectrum
11/10/2011
911/10/2011
Grism
Direct
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Detection of Sources
• Identify all point sources in grism image• Mask 0th order objects with HF140W < 22.5• Create extraction box in direct image around
candidates from grism image• Match sources within that box to objects in
master catalog• Visually inspect the extracted spectrum
11/10/2011
1111/10/2011
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Detection of Sources
• Identify all point sources in grism image• Mask 0th order objects with HF140W < 22.5• Create extraction box in direct image around
candidates from grism image• Match sources within that box to objects in
master catalog• Visually inspect the extracted spectrum
11/10/2011
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Sanity Check
• Arjen found two objects in the ERS pointing• I blindly found his two, plus an additional
object that is possibly an Hα source at z=1• Broad-band photometry confirmed the excess
in the J-band
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Advantages
• Can be used to find these objects at different redshifts and at lower S/N
• Not forced to use the 3D-HST catalog– Can find objects fainter than the HF140W < 25 limit
• Simple enough to be done right now!
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But…
• It’s not 100% automated• Current 3D-HST coverage is missing the
pointings that Arjen used in UDS and GOODS-S– Only have the single ERS pointing as a test
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Conclusion
• Our small test showed promising results• Can we assume that this is enough and
continue with other fields?• Or we can look for high-EW objects in the 3D-
HST catalog (in-progress for GOODS-S 27)• Eventually want to be able to make detections
deep into the noise
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0th Order Magnitude Calibration
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0th Order Flux Calibration
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