SCP Meeting Notes, January 20, 1999

I have a broken finger this week, so my typing speed is a little slower, plus I keep hitting extra keys that I didn't want to hit, so we'll see how the notes go.


Deep SN Final Refs Update

Final refs. Greg got some at Chile; the run wasn't an unmitigated success, but they got something. Between that and WIYN, Rob believes that we got most of what we need from the December 1997 supernovae, but he hasn't done the accounting to really know.


HST Snapshot Status

Richard Ellis says we have to come up with a target list and RPS2 (and a budget) for the HST snapshot survey. Somebody needs to figure out which hosts we need. Peter has volunteered to do the RPS2 if somebody gets him the target list.

There is some talk of getting colors (general feeling is that we usually already have those from the ground). Also, which filter would we use. All these things need to be thought about, along with a target list.

Saul mentions that Richard Ellis may be coming to the US. It's still in negotiation, but it's an open secret that Hawaii has offered him him the directorship of IFA.


Extinction of our Deep SNe

Saul says he's been in contact with Pilar. She has a student working on the extinction curves of four of our supernovae. Peter whispers to Rob that he's trying to so this all from the spectra, and Rob's eyes go wide. At any rate, at this stage we have to get him the ligtcurves. Apparently he would need how much host was subtracted at each point. Rob can get this information out with just a little bit of work, but it will take a lot of work thereafter to get the data properly cooked.

Saul says we need to make it clear that the data won't be published until Isobel has published it.

Saul says he talked to Isobel, who is going to push on getting the spectra paper out. There may be a communication gap between Isobel and Peter, re: who's waiting for whom, but presumably talking can fix this.


Alex Conley and the HST

Alex Conley is back. Little research has happend, he says. He wants to figure out why Greg's method for lining up images work unless there is any rotation between the images. Greg's method is to use all of the objects on the four chips, and get the RAs and Decs. You then plot the offsets, and pick the things in the peak as objects to use. He says there is a nice sharp peak. However, he has trouble with the last step if there are rotations. He has no idea how long it will take to get this to work.

There is pressure, because the images are starting to go public now (one year after they were taken). Rob is going to try to help Alex work through this.


Nearby Campaign Preparation

Robert is still fixing little bugs, adding new features. Robert says that LinCal is up right now. He has printouts from a couple of months. You can get to it off of the nearby search page.

Peter says that we should start collecting the supernovae from the IAU circular. Robert says that they could go into What's Up, and he assures Rob that we can set priorities so that these won't overwrite ours when we finally start getting ours. Well, OK, it isn't in now, but he knows that we want it, so he'll work on it.

We have barraged Robert with a huge flow of suggestions and demand. He should go off and have fun.


Miscellaneous

Susana says new new advances re: the Chew's Ridge telescope. No dates have been set for anything. She says she synced two low redshift databases. There was some discussion of databases and junk. Not much.

Saul mentions that when Greg gets back, we should all talk about who's flying when to which telescope.

Lots of talk about the putative Japanese space station telescope project, and how we have to decide what it is that we really want to do. I didn't archive most of this discussion.

Peter brought up that his favorite next huge-data-needed project is to look for a lensed supernova. I didn't archive this full discussion.

Mike is working on the C code for aperture, so he can figure out position errors and have them be reasonable, not junk. He's learning how correlated errors work. This is all towards figuring out why the position errors he mentioned last week were turning out odd.

Lots of talk about writing papers on this, and the last few numbers Peter needs, and how papers are all basically done. See previous group meeting notes for the text of this discussion.

Peter is also supposedly picking up the K-correction story. Saul is also asking about the R_B stuff (color dependent K-corrections). Peter wants Alex Kim to get involved in that, and it's a whole mess.

Peter was on a paper that got completed and submitted to ApJ about HDF supernovae. He's going to talk about it on Friday at the Journal Club. He's done lots of Type-II K-corrections for this paper, which should be useful stuff.

Alex Lewin is still figuring out the Omega fitting program. She's sort of figured out how to run snminuit. She's using Robert's Omega fitted.


CCD Update

Don said he did nothing last week because he was sick. He says he did revise the CCD web homepage. He has a new paper online, and is preparing a talk for the SPIE meeting on Monday in San Jose. He also put the new CCD results there, test images, plots of noise and charge transfer efficiency. Steve got images with the 2048 CCD, Don says. With luck, they're a few weeks away from getting the red half of the backside QE measured, so that they can compare with calculations. Don says he is getting eaten alive by test data.

Don says that he thinks he now understands the T dependence of the absorption length in silicon. The band gap moves to slightly higher energies, so the red cutoff moves in (it is slightly worse). Also, Don mentions that because of the IR index of refraction of ITO, we don't have the right coatings yet at 1 micron. More coatings will need to be put on.


The Continuing Lightcurve/Stretch Paper Story

Gerson shows us a difference plot, between the averaged single lightcurve and the new extended template. Gerson has worked on improving the template. He did it first by fitting our data, and did... something (later he says he added a parabola which is 0 at the endpoints)... for two regions of 10 days. There are a couple regions where our data and Hamuy data do different things.

Now as a result the curve looks much better, he says. He then got the minuit program from Don, and redid all the various cases (cuts on epoch and stretch) with the composite lightcurve (or, rather, all of the data). It looks much better than it did before; Don is impressed.

In other words, you get the same stretch from early and late lightcurves.Gerson also did the chisquare per degree of freedom for each 10 days. Note that Gerson increased the errors on the Hamuy data by sqrt(3), because chisquare was coming out too small. He also did it taking out the worst outlyer (single day). Results? Ask him to show you.

So, when people ask us if there are any deviations left over after stretch, we can say that there are no statistically significant deviations on a timescale longer than a day.

Gerson wants to get this out to the collaboration before the nearby search hits the fan....