APOGEE: stellar masses from astroseismology --> ages <--> abundances

Just took a quick look at the fabulous ASCAP results:
they have beautiful masses for a whole bunch of giants with [Fe/H] and
[alpha/Fe] ; they list evolutionary phase and masses;
given the abundances this translates / should translate into ages (e.g. Padova isochrones).

Next time I have a minute, I should just plot t_age = f( [Fe/H], [a/Fe] );
and ask Marc P. why the ages are not explicitly listed.


Some notes (June 2014) after Marie Martig's trials and tribulations:

What we get reliably is:
1) log g; then 2) mass (where Teff comes into the scaling)
we have modest faith in [Fe/H], and something seems screwy with
T_eff (let's get dereddened colors from PS1 or the "amateur survey").

Marie's proposal:
let's rely on log-g and masses only; but even that relationship relies somewhat on
the abundances...

need to discuss age-priors

precision AGN dust torus reverberation mapping with NIRSPEC@JWST IFU

Thoughts during a NIRSPEC IST meeting on possible nearby-galaxy GTO programs in 2019+

The geometry of the dust torus in Seyferts can be mapped by watching the dust response
to accretion disk variations. I got excited about (and learned about) this topic in the
context of Kirsten Schnülle's and J-U Pott's paper (Schnülle et al 2013)
on 5-band monitoring of NGC 4151.

If one considers the 3"x3" IFU with 30x30 0.1"x0.1" pixels and the R=100 grim,
one should get:
 -- wavelength coverage from 0.8 - 5 mum
 -- reproducability and flexibility <1%
 -- very high S/N
 -- very high spatial resolution to subtract stellar body...

Worth a chat with Bernhard D., Kirsten, J-U ..

Data sets for proper motions in the Galactic planebcsv

In the context of Nina getting the best data sets for doing proper motion in the Galactic plane,
various discussions (Nina, David, Zeljko) have occurred on what data sets to combine with PS1
data for the most productive proper motion constraints. It seems there should be two sets of criteria:

-- what does the data set add in terms of  dmu ~ FWHM / (S/N) / Depoch

-- how painful are systematic issues, such as photo-plate boundaries etc..


SDSS-overlap areas
  -- take SDSS as an additional epoch
      * SDSS positions are based on the r-band; check what information arises
          from the g band position measurements
  -- take mu(SDSS-POSS) as a prior, rather than deal with (a,d)(POSS) itself
       * work out how to deal with the fact that mu(SDSS-POSS) may have systematics
UKIDSS: could be very interesting the galactic plane:
Questions:
  -- when are the observation epochs of the survey
  --  practical access: get the whole darn thing and add to LSD?
  -- some links
       http://www.astrogrid.org/agpython.html
       http://surveys.roe.ac.uk/wsa/theSurveys.html

Areas that have neither UKIDSS nor SDSS?
   -- take 2MASS, or is it not worth it?
   --

RR Lyrae in PS1

Nina's working out lots of things about how to do QSO variability right.

Questions arises what would need to be changed to apply same formalism to RR Lyrae.

If one uses Gaussian process (Hogg's advice), then one needs to specify the appropriate
covariance function.

Hogg recommends the covariance corresponding to a damped oscillator.

HWR's thoughts:

Take a covariance that corresponds to range of periods of near-sinusoidal oscillation.
It will look periodic for Dt's corresponding to a few periods, but look like
white noise expectations for long time-intervals.
That way, for short time intervals it matches well, but one is not stuck with the cumbersome
period matching over very long periods.

For thinking about how to write down a suitable GP covariance function, I found it useful
to do a lot of staring at the plots from Sesar's 2010 paper (his Fig 9)

It nicely shows:

• the level of lightcurve asymmetry: slow fall, very rapid rise
• the fact that the g-r color changes drastically but the i-z not at all (just Teff?)

Project thoughts

1) Kinematic Consensus:
 

Basic idea: seach for stream members in Integral-of-Motion space, by making the
  grossly simplified assumption of spherical potential and some plausible radial profile.
  The first issue to be explored is: we have excellent (alph,del), good D_photo, v_los, but no v_perp.
  How does that mapping back into integral of motion space look like?

  Hogg will see how far he gets; Zhitai will start perhaps in this direction [TBD]

  Document at https://github.com/davidwhogg/KinematicConsensus/tree/master/documents


2) Long (and for me fruitful) discussion with Bovy led to rediscovery of math in Helmi & White 99
    Question remains: what is the best practical way to "fit streams" (and infer potential)
    from incomplete, or at least imperfect, (x,v) information on relatively few stars.
    In the end, it all boils down to being able to write down L( (x,v), J,theta,Dt's) where the Dt's
    are the times at which the stars were lost.  [Bovy's blackboard notes]

3) Astrometric Übercalibration thoughts:

notes from meeting with Oxonians

LSD 101 for HWR

Notes from an 'idiot's tutorial' on how to get to LSD data base tools
on MPIA computers, and then link this to pythoning... (E. Schlafly --> HWR)

As of July 2013 the PS1 stuff is migrating to aida41233; so: ssh -Y aida41233

then: 

> source /disk/LSD/LSD/lsd_environment_a41233_2
> ipython --pylab

within python


plot(arange(10))  % test whether plotting windows

from lsd import bounds  %
import util_efs_pub
ob=util_efs_pub.query_lsd('select * from ucal_magsqw',bounds=bounds.beam(150.,50.,1.))
% the syntax of that query should be like sql; in essence get "everything" within 1 degree of (150,50)
len(ob)
ob.dtype %take a look at what's in the table
m = numpy.sum(ob['namg_ok']>0,axis=1) >=3
m = numpy.sum(ob['nmag_ok']>0,axis=1) >=3  % pick out those object with good detection in 3 bands
clf(); plot(ob['ra'][m], ab['dec'][m], ',')  % make a plot
clf(); plot(ob['ra'][m], ob['dec'][m], ',')
clf() ; plot(ob['mean'][:,0]-ob['mean'][:,1],ob['mean'][:,0], ',')   % make a CMD
ob.dtype

%save first_lsd_steps 1-18   % that saves the session
ob=util_efs_pub.query_lsd('select * from ucal_magsqw , sdss(matchedto=ucal_magsqw)',bounds=bounds.beam(150.,50.,1.))  % cross-matched catalog
ob_stack=util_efs_pub.query_lsd('select * from stack , sdss(matchedto=stack)',bounds=bounds.beam(150.,50.,1.))   % query stacked catalog
ob_stack=util_efs_pub.query_lsd('select * from ps1_det , sdss(matchedto=ps1_det)',bounds=bounds.beam(150.,50.,1.))
ob_stack.dtype
ob_ps1_det=util_efs_pub.query_lsd('select * from ps1_det , sdss(matchedto=ps1_det)',bounds=bounds.beam(150.,50.,1.))


Issues: there is no single data base that has everything; e.g. to get proper motions,
 one has to talk to Bertrand where this information is....


subsequent e-mail from Eddie

The database that Bertrand has made with Gene's proper motions is in:
/a41217d5/LSD/PS1/tpifeb13
That means if your LSD_DB includes /a41217d5/LSD/PS1
then you can get at the proper motions via
select * from tpifeb13
or
select * from ucal_magsqw, tpifeb13(matchedto=tpifeb13) ...
and things should work.

MilkyWay Kinematics with Astrometry from PS1 (and SDSS)

Some thoughts on how to go about getting the best proper motions in the ICR from PS1

Stream finding & stream follow-up with PS1

I might want to get back into the stream analysis business again. Variety of angles: it's part of the SFB 881 project; I would like to see how well proper motion cleaning works for finding stellar halo streams traced by giants; a good test case to combine proper motions between PS1 & SDSS.

Possible starting point: the Pisces stream, recently found by Martin et al (http://arxiv.org/pdf/1302.2155v1.pdf). This stream appears to be traced in giants,
at a goodly distance of 35 kpc. I wonder whether one can do both a photometric metallicity "cleaning" of the stream, using ugr [XX will look at the metallicity diagnostic of old giants in the
ugr plane]; and the contaminant MS stars at g-r=0.6 and r<19.5 should be at ~3 kpc, where their
dispersion should be ~>60 km/s, hence detectable by proper motions...
This might lead me to re-open the questio of optimal filtering a la Koposov et al 2010.

PS1 and astrometry:
Bertrand G. took the PS1 pipeline proper motions and did the mean proper motions of known SDSS quasars in 4x4deg fields. The mean proper motion (reflecting the deviation from an inertial frame),
showed a smooth pattern with an amplitude of ~10 mas/yr.

He will take half the QSO sample correct the other half and see what happens.
That seems to imply that the calibration to the QSO's should work well.
That, in turn, bring new motivation to identify all PS1 quasars by a mix of WISE colors
and variability. In particular, we will need to look at the regions of considerable extinction
at low latitude.  So, let's find quasars at |b|<15, to map the Galaxy.

Age vs [Fe/H] in the solar neighborhood

We should check at some point that we get the age distribution,
at a given metallicity, in the solar neighborhood (e.g. Schönrich & Binney)
right in the Stinson et al simulations.

1st GES science meeting

Had some interesting conversations at the GES meeting:

-- immediate things to do:
    * get access to the Edinburgh archive with Michelle and get the FGK stars out
    * try to cross-match this with PS1 photometer
    * distances should not come from only log_g; photometry has to come in.

--  mid-run:
     * get best distances
     * cross-correlate abundances GES-SDSS to get them at the same footing
     * we need to get the best proper motions!!

We should see whether we can do a more complete map of the GD1 stream with PS1 data; also we should look at the orphan stream. With the nest PS1 data that should all be possible.