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LSST DESC Blending Task Force - Shared screen with speaker view
Henry Ferguson
28:40
Unrecognized blends: Seems fairly straightforward to provide “hints” in the database — a few parameters that would indicate that it might be a blend. This would be a few parameters that capture clumpiness, asymmetry, and non-uniformity of colors. This lets you identify sources for post-processing or for eliminating from further analysis.
esheldon
28:53
I have a question
Alexie Leauthaud-Harnett
30:16
I have a question for Peter: when you are fitting for the SED, can we also fit for the redshift at the same time that we perform deblending?
Henry Ferguson
33:17
Looks like the algorithm imposes *hard* constraints that the objects have uniform color — i.e. wavelength-independent morphologies. This means that it will be impossible to have the de-blended objects have color gradients. Is that correct? Is there a way to soften this to allow modest color gradients?
Henry Ferguson
33:39
Apologies…I have a conflicting meeting starting in 2 minutes, so have to sign off.
pmelchior
34:29
Not quite, Harry. Fred will talk about two-component models, which is the right way of accounting “color gradients”
Chris Walter
42:41
After you find the most obvious objects do you go back with that model to refine the list of remaining detections?
pmelchior
43:13
@Chris: Not yet, but worthwhile discussing
Douglas Clowe
45:23
have you tried this on a larger spiral and seen if you over-deblend when you have visible arms?
Jon Loveday
46:13
Presumably the monotonicity constraint would shred large spiral galaxies?
pmelchior
47:38
@Jon: Yes. But we could allow for azimuthal variation, as long as the radial profile is declining. I’m looking into that.
Gary Bernstein
51:19
Does the algorithm produce uncertainties on fluxes or other quantities, e.g. by samples of some posterior?