SCP Meeting Notes, 1998 August 12


Proposals, the Butt-Deep Search, and What To Do With Keck

September is going to be a proposal nightmare.

--G. Aldering

Saul says that one of the problems we are going to have is figuring out what to ask for in the Keck and HST proposals. Saul says that if Brenda Fry comes up tomorrow, perhaps we should talk to her about what that group is doing with the Keck, to see if we could coordinate by choosing targets that will complement the science we're going to do.

Perhaps we will do a little more if we see any results in the HST search we plan to attempt on the HST data we already have in hand.

Greg says that we need to worry about the followup; finding the first one is important, but after that there's no point if we can't follow it up. Greg speculates that we might be able to get 6 nights one semester, instead of 3 one semester and three the next, so that we can be sure to find something and line up HST for followup. Another thought is that six half nights makes more sense for us, but right now the UC Keck doesn't do half-nights.

Saul wonders if we could share half-nights with Broadhurst ahead of time. The trick would be getting them to be scheduled in the style that we get scheduled. If we can find anybody who's willing to do that, we'd be fine.

Greg also mentions that since we've got the nearby search set up for next spring, it might be hard to try to do a 6-night Keck search at the same time. If we do that, we have to really commit serious resources to it.

Proposing to do the same thing at Keck means a inferior proposal to what were given time for this semester, since we won't have NICMOS. Saul wonders if we could try to get the CFHT/AO people involved in this somehow. Greg says that a 4m even with AO doesn't go deep enough for IR photometry or spectroscopy for what we would be finding with a Keck supernova.

In short, probably we need to do our followup at Keck, and we need to do it best when Keck has AO. So, perhaps the thing to do would be to apply to see if we can get credit for nights which we would then use next fall. (This would solve the problem of needing AO, and solve the problem of overlapping with the nearby search.) General sentiment seems to be that it may not be likely that we will be able to get any kind of "night banking" commitment from Keck.

Greg is worried that if we put in the same proposal next time around, since it will be worse, we could gt nothing... and in the long term, that would be bad to have on our record. Saul says that it depends what happens this fall. If we don't get good time this year, then we need the pilot study next term. Of course, that's probably no good for the proposals, since the TAC won't want to do 3 nights of Keck time for "proof of concept," nor will we have the results from our current semester in hand yet.

The other thing to put in for Keck is to go back to what we've been doing, and say that CFHT will feed us z=0.83 supernovae which we will confirm with Keck and get excellent colors from HST and the ground.

Peter says that we can put in for kickbutt spectroscopy of Reynald's supernovae and high resolution spectroscopy of nearby supernovae... and then do what we want with the time. Whether or not we can service another search, it sounds like whatever we do, Reynald is going to do a search, so getting spectroscopy of those supernovae is a good thing to do.

Of course, we have to make sure to coordinate with Reynald and make sure that the CFHT proposal is being done right. Of course, if it's a scheduling problem, we can move Keck to match. (This year, the problem was NICMOS was very time limited.)

...so, it seems we are converging on a more "traditional" Keck proposal, (plus high qualtiy spectroscopy) unless they will let us bank nights and use them in the fall.

Keck proposal deadline is September 16th, and Greg and Rob are going to be gone the four days before that, which is scary having Rob signed up for Keck, although Peter has to write the explanation of what we're looking for.


Other Proposals

Other proposals: a whole "whack" for nearby. CTIO for spectroscopy. What about WIYN? Doesn't have longslit spectroscopy capabilities. WIYN is too big for photometry of the nearby supernovae. Do we put in a WIYN proposal? Peter reminds us that we phrased the last proposal saying that we are finished with the intermediate supernovae. So, we can write it for final refs and just inflate it a little bit. Susana is going to do WIYN.


Miscellaneous Updates

Greg says he is still putting together the whole "source our HST data for supernovae" thing. We need the results of this to decide what we're going to do for the HST proposal. Greg mentions that he should get Peter to do a simulation of an HST search to find out what we might get.

Alex (Conley) at some point is going to start doing some stuff on the WFPC data; however, that's orthognal to Greg looking for supernovae on the HST data.

Rob is still working on the database and then will do the subtraction/scan stuff, getting it up to snuff for the Keck and then later runs.

Kirsten is doing lots and lots and lots of runs on this spectrum fitter. She says that she thinks it's working. It usually gets within a day of the right day. There is still more to go into it.

Marcus is getting close to being done. He's had to rederive some of the boundray conditions from the ..., Press, and Kirshner paper he was trying to implement code from. He's writing everything so that it can be called from IDL.

Robert is working on Nelson's Omega/Lambda fitting routine. It's now significantly faster (Peter's is faster as well). Peter says he can do the full gigantic 4d fit in 9 minutes instead of 2.3 hours. He fixed a lot of little things. Peter thought it was expensive to spit data back and forth between the nodes, but actually it's faster to do that than store it in big arrays. Now he has them all talk to each other constantly, and each node writes out its own data file. It's also smaller memory-wise as well. He says on our 6 PC's, he can do a model in 27 minutes.


The Chew's [sic?] Ridge Telescope

Jarro and Susana tells us about the nearby telescope. Is there any shot at being able to use this telescope to followup any nearby supernovae we can find? Susana says a decent shot... she says the estimated moving date is sometime in October. Saul questions, after the telescope is moved, how long will it be before the telescope gets up to snuff and works well enough to be usable. Susana says that there is some tracking problems; the primary mirror slops around. She doesn't know how much the secondary structure is affecting this, and how much of it is due to the friction drive slipping. There are tracking problems on the timescale of a few minutes.

We shall see.

Jarah has been working on computers and the weather station out at the telescope. The weather station is hooked up to a PC running Linux. It's got RPC set up, and there is a client on Goddess which can question anything. He has a demo website up at goddess.lbl.gov/~jarah/Weather2.cgi, except that the server isn't up at the time. Susana says she has a demo on her web page as well.


The Neverending Paper Story

Paper: we thought we were in the last final moments (AGAIN) when, Saul tells us, we discovered an interesting chisquare issue. (Does this surprise anybody? We will ALWAYS discover another issue.)

The problem has to do with chisquare. Chisquare is the sum of (residual/error) squared. Our residual is a function of Omega_M, Omega_L, Script_M, and Alpha (stretch/mag slope). The problem is, propogating the error on the residual, it's a function of the errorbar on the magnitude, the errobar on the stretch factor... however, the errorbar on the stretch factor includes an uncertainy on alpha, the denominator keeps changing based on what alpha is. If alpha is poorly constrained by the data, then your chisquare fit will home in on an alpha that maximizes the uncertainty in the stretch. So, alpha was getting pushed as high as it could get before really distorting the residuals. So, we have to go back and redo everything, and currently we are trying to figure out the right way to do things. One thing we do is fix the alpha (alpha_test, call it) that is used to determine the error bar on the stretch correction.


Postscript (Not the Printer Language)

At this point, your humble court recorder had to run off and set up for tea. However, I'm told afterwards that there was news about the CCD. Apparently, whatever was going to be done "down there" is done, and they are back up here. They are etched, and making progress, and perhaps by the end of September we will have actual devices.

Apparently, there's also something having to do with Peter applying for a faculty job at Chicago. Shrug.