--------------- From: Frank Masci Subject: Re: Experiment 1 Date: April 3, 2014 at 3:50:18 PM PDT To: Tim Conrow , John Fowler , Howard McCallon , Howard McCallon , Roc Cutri , Carl Grillmair Here are plots of Ks - w?mpro comparing the nominal/old run (linearity-correction turned on) to the new one with linearity- correction turned off. The behavior is consistent with previous analyses: it doesn¿t nudge things enough at the bright end; in fact, it actually throws the color locus off the zero-line for W1 >~ 8. The scatter for ¿lincor on" is also smaller. For clarity, the blue points (¿linearity on¿) have been shifted to the left by 0.5 mag. http://wise2.ipac.caltech.edu/proj/fmasci/neowisercmds/2massK-w1mpro_44581a_NLoff.pdf http://wise2.ipac.caltech.edu/proj/fmasci/neowisercmds/2massK-w2mpro_44581a_NLoff.pdf Also, attached is a difference image of L1b frames: ¿linearity correction on" - ¿linearity correction off¿. The color bar gives the range of DN values. It goes in the expected direction, but I¿m stumped as to why masking more of the core would give a fainter wpro flux (earlier email). Perhaps these detectors behave so differently at these regimes that the linearity correction should really be ¿negative¿, that is, there's too much extraneous signal to start with before we apply the linearity correction? *** Tim - feel free to restore the ¿nonlin¿ cal files under ¿ifr_t/44517b001-44604a273/" to their former versions before the next experiment. Regards, Frank ----------------- Given W2 from cryo had a large bias and assuming it’s the same manifestation as that which caused W1 to go south in post-cryo, I’m inclined to think it’s not wpro related, but ical related instead. Something I’ve been tossing around is a bad linearity correction. That is, suppose the linearity correction was too severe, i.e., cores are getting more amplified relative to wings. Given the template PSFs were derived from unsaturated data, they’re not applicable to bright/saturated sources because their core-to-wing contrast is flat wrong (getting progressively worse for brighter sources). Fitting a PSF to a narrower source profile (affected by a linearity overcorrection) must lead to brighter fluxes. Right Carl? Regards, Frank On Apr 2, 2014, at 11:37 AM, Tim Conrow wrote: Looking at svn diffs, there was a big change to v5 wphot; we basically grafted on the wphotmf wpro and called it wpro_v5, along with some support routines including the infamous estmode.f routine for finding the mode to use as a BG estimate. We changed the BG finding routine again in v6 (inherited by v7), so I don't see how we can blame estmode. I don't immediately remember what the differences were between wpro_v4 and wpro_v5 (MF wpro). I'll look at that next. -- Tim On Apr 2, 2014, at 113058, Frank Masci wrote: Also, wanted to point out that since W2 in cryo had a pretty large bias (cf. to W1), then if it's a bug, it must be present in v4.0 wphot. So, the problem must originate in cryo processing, not post-cryo as Tim mentioned. Some detail in either detector behavior and/or pipeline parameters in v5.0 (not psfs of course) made the problem worse for W1. Regards, Frank On Apr 2, 2014, at 11:21 AM, Frank Masci wrote: Also, it’s interesting that the damage is greater for W1 (using neowiser 3/28 psfs) relative to cryo than it is for W2. E.g., recall these plots from yesterday. http://wise2.ipac.caltech.edu/proj/fmasci/neowisercmds/2massK-w1mpro_44581a_05901b.pdf http://wise2.ipac.caltech.edu/proj/fmasci/neowisercmds/2massK-w2mpro_44581a_05901b.pdf Regards, Frank