MAPs and scale lengths with APOGEE RC *'s

Had conversation with Bovy what the trial and tribulations might be to
do MAP scale lengths using the RC stars from APOGEE:

simplest version:
-- focus on apocenter quadrant (bearable reddening)
-- each star in the RC catalog has a distance and a reddening attached to it.
-- to the extent that RC *'s are standard candles, and enter the sample down
   to the apparent magnitude limit, the selection function/volume issue
   should be analogous to the unreddened case, except for exp(-tau_H)/D^2
-- focus on stars at +-4 degrees ftp, the Galactic plane --> don't care about scale-height.


simplest science question, what is R_exp([Fe/H] | [a/Fe]~0)?
is it flat for the metal poor stars?

3D-HST Notes; May 2014

The 3D HST proposal talked a lot about environment dependence of galaxy properties, but nobody has done anything with it, nor seem they eager to do so. I have started to do a little bit of reading up on the practicalities. There is a whole bunch of papers recently that discuss and compare different environment definitions, e.g. Muldrew et al (2012) and Skibba et al (2012). It looks to me that the mark (by stellar mass, compactness, etc..) correlation function is the most sensible way to go, at least Skibba claims it to be so.

I am now combing the literature for comments (solutions) on two specific issues, relevant for 3D-HST:
-- field size (typically 5-ish MPC transverse)
-- grism redshift accuracy: 750 km/s for emission line galaxies, 1500 km/s for absorption line galaxies (m<23); this us squarely between the photo-z surveys and the spectroscopic surveys.

It seems that the PRIMUS folks, in a -- at first glance very nice paper Skibba et al (2014) -- have gone a long way of working out this regime. They have, however, far larger sample sizes and larger (angular) fields. I still haven't found an explicit treatment of field-edges; perhaps the randomization takes care of it.

Basic method of redshift distortions is worked out in Fisher et al (1994).

Also: I don't understand why still "estimators" are used for correlation functions, marked or not,
used. I would presume that any parameterized model for a correlation function (power-law with r0 and gamma) should make a prediction for p(r_p, π  ), which then brings you to likelihood approaches. Why is that not done?

Post discussion lessons:
-- perhaps the simplest and first thing to try is to ask, whether indeed -- at a given mass -- quiescent galaxies ase more clustered than SF ones. How to do this: look at the quiescence-marked correlation, using the unmarked correlation as the "random" (D. Wake's suggestion).

post Calistoga

Project ideas not to drop:

-- high spatial resolution Y-band spectra of luminous ellipticals (Conroy)

-- binary population with Nidever;
   work out giant ages from giant masses in binaries (Gaia & APOGEE)

-- testing PS1 RR Lyrae in dSph in the MW

-- clarify wide-field spectroscopy telescope (Bernstein)

Notes on the "shallow" JWST NIRSPEC survey of 9000 galaxies

Goal: mini-SDSS at z~2-4
Science case: Arjen's ESO large proposal, but now at z~2-4

2 settings R~1000 & R~1000
S/N goal per resolution element 20

Basic targeting m_AB(integrated, @H or IRAC3.6)<24.5; z>2
[and add the ones that are IRAC-only detections…]

according to Tracy Beck: we get ~150 galaxies per MSA setting [CHECK using APT]

thought: 1x 1000 sec @ 1MSA (or 2x500 sec dithered with 2 slits; is that needed)

thought 36 pointings   --> 36x150 galaxies --> 5500 galaxies

Field:  from CANDELS with ALMA access; 2 different fields;
   within a field, contiguous.

  what are the overhead advantages and cosmic variance drawbacks of different
   MSA settings at identical pointing

To be done: what is the S/N distribution, given actual CANDELS size/slitloss parameters.
 any orient constraints: major axis.

Draft needs to be done by May 9

After the Oxberg meeting April 1-2

Two immediate homework's have arisen:

1) Hogg & Price-Wheelan will work through the known streams, and see what
feasable observational data are most potential-constraining; then the plan could be that
Brani organizes a coherent follow-up effort.

2) Discussion between Schönrich, Martig, Binney have arisen that it would be good
to have action-space diffusion coefficients from numerical/cosmological simulations.
Bovy and Roskar have a machinery that takes N-body simulations to an analytic potential
machinery, which then allows the Stäckel fudge, and ultimately to calculate
the actions for a particle with (x,v) in an N-body simulation.
At a practical level, it needs to be cleared-up what these diffusion coefficients
depend on t,R,sigma?

The claim is that with p(J,age,[X/H] | t_now) one can get the diffusion history,
under the assumption of p(J,age,[X/H]) was very narrow at birth.


3) Needs to define paper scope with Nina
4) Need to define paper scope with Marie

getting to the Gaia mock Universe

Some notes on practicalities of getting to the A.Robin (?) mock Gaia Universe.

The basic stuff for my purpose is the gums.mw table,
described in http://dc.zah.uni-heidelberg.de/tableinfo/gums.mw

How to get to it:
what works: go to topcoat (download as needed)
and follow instructions in http://voparis-europlanet.obspm.fr/utilities/Tuto_TopCat.pdf

You don't get the file, but you can SQL-type query it.

You get 1.000.000 records easily, but I still have to figure out how
to get the whole file, e.g. as a binary fits.
Markus Demleitner at ARI is the person to talk to; here is what he advises:

Uncheck "synchronuous"; this selects async operation, which lets
you even change your location and IP and retrieve the result later;
also, it gives you, by default, 3600 seconds of query time before
timing out.

magg<17.5 is still a large number of objects and hence a very large
table (I'd expect several 1e8 rows), probably too big for TOPCAT to
keep in memory or to handle directly (though it might be ready
before the 3600 s timeout).  

You could use STILTS to stream things to your disk and select FITS
binary output (see stilts tapquery); but it'd certainly be preferable
if you gave some additional constraints to offload part of your
computation to the server (note that you can also upload your own
object lists).  The server already has indices in place, quite some
memory, etc., so it usually pays to let it do the heavy lifting and
keep the tables you actually deal with of order 1e6 or maybe 1e7
rows.

I am now working on downloading the fits file directly,

and do them with p. in subdir GaiaSims in Apogee.

Dynamics of K or G dwarfs near the mid-plane

Some thoughts on how to serious is practice about the dynamical modeling
a la Bovy using G and K dwarfs near the galactic mid plane from the SEGUE scans.

1) query all G and K stars with b<30 & spectra in DR10

2) where do we get a/Fe from?

3) get the proper motions both from SDSS and from PS1

4) this is the test-sample on which to compare the two proper motion estimates…

5) do we need to deredden individually?