The 2MASS Galaxy Catalog

Ouline

ABSTRACT

INTRODUCTION

a. overview of 2mass project (what is it, numbers, scientific objectives)
b. Extended Sources; brief discussion of some of the science projects geared towards 2MASS galaxies & ext. srcs; introduce or reiterate level-1 specs
c. data release and overview of data covered in this paper
d. GIVE bullet summary (ala T.Chester)
e. outline objectives of paper and forecast future papers to come

review data products (relevant to galaxies) and define 2MASS data type (e.g., what is a scan/tile; what is a coadd; postage stamp, etc).

**briefly** introduce catalog parameters (this is so long and complex that an entire chapter needs to be devoted to this)

tabulate data set introduced in paper; discuss/outline "mini-release data and march'99 incremental release

might be a good point to flash some real data (one or two coadds and some postage stamps) for flavor

STAR-GALAXY DISCRIMINATION & ALGORITHMS

overview of work in the field, including those of the POSSI people (odewahn) and the POSSII people (weir); traditional X-Y "cart" methods, decisions trees and neural nets.

2mass source detection and types of things detected (stars, multiple stars, extra-galac pt srcs, galaxies, artifacts)

introduce & define our primary discriminents ("sh","wsh" & "r23"). Here we need to discuss stellar ridges and atmos-seeing in general.

briefly introduce other star-galaxy discriminators

introduce the use of oblique decision trees and how we employ them

summarize our completeness and reliability (later we will give further proof with galaxy counts) after applying simple "cart" thresholds (i.e., "sh" and "wsh") and OBDTs.

future direction (different DTs and auto-classifiers)

EXTENDED SOURCE CATALOG

the objective of this section is to discuss/introduce the detailed output of GALWORKS (mostly mags). a table might be sufficient with some additional descripts or notes. the table might look very similar to the one generated by the DB (or catscan ... whatever). we might also delve more deeply into some of the trickier parameters of GALWORKS (like ellipse fitting)

highlight some of the more "important" forms of photometry (i.e., impose our own personal bias on what mags people should be looking at): fixed circ r=7 and K-fid isophotal.

FIRST RESULTS

a. Galaxy Counts & Completeness (with reliability relevant to faintest bins); how do counts stack up with previous work and with pencil beam studies; can we help clarify the great debate: no evolution, modest evolution, copious evolution (the answer is: not likely, since the models only begin to diverge at our faintest mag bins)
b. Colors (& discuss reddening due to redshift)

DISCUSSION

given the results presented above, what projections can we make for the remaining survey (total number of gals, reliability, artifact rate, etc)

prospects of cross-matching with other cats (SDSS, POSSII)

large scale structure and introduction of the 2MASS cluster catalog (and any other projects now underway like the Schneider/Hucra KEY project)

SUMMARY

CONCERNS

how do we handle the three stellar number density divisions: low, moderate and high (galactic plane) ? the above outline was drafted with the "low" density fields in mind. Moderate and high density field data is potentially the most exciting data set, but they are frought with complexity and unique probs. It is thus natural to "introduce" the low density field data as our best case set (or rather, the best we can hope for results), then later dive into the galactic plane data. So, I am suggesting that we put off the G-plane galaxies for another time (say, the second incremental release or earlier). comments please (-tj)

Notes:

from T.Chester (981001):

some first comments:

paper needs a "caveats" section!!

i agree with your sentiments to confine most of this paper to low source density analysis. however, since this is meant to accompany the release, you'll need to have a section devoted to at least a brief overview of what happens in high source density areas (primarily thresholds and numbers of galaxies).

this paper is likely to be too unwieldy if you discuss much performance here, hence i would recommend that you plan 3 papers:

The 2MASS Galaxy Catalog I: Overview and Algorithms this would include pretty much what you have in the outline, but only basic "first results" would be given here, such as number and thresholds versus source density, c & r overview, and basic colors, including vs. z.

The 2MASS Galaxy Catalog II: Performance in areas with low source density

The 2MASS Galaxy Catalog III: Performance in areas with high source density

other comments:

INTRODUCTION

a. overview of 2mass project (what is it, numbers, scientific objectives)
** make this brief and just reference other papers (presumably a skrutskie et al paper)

b. Extended Sources; brief discussion of some of the science projects geared towards 2MASS galaxies & ext. srcs; introduce or
** not sure any discussion of science projects needed here - just confine this paper to gal cat, and give a few sentences about the scientific usefulness of this catalog

e. outline objectives of paper and forecast future papers to come
** confine forecast to just II and III.

schneider is spelled wrong.

> >paper needs a "caveats" section!!
> yes you are right!!
> also, it might be helpful to have a section dedicated
> to artifacts and other bad guys that the user may
> encounter (artis are a caveat by themselves)


absolutely - why didn't i think of that?

> >here, hence i would recommend that you plan 3 papers: >
> do you mean that we should make three paper
> (simultaneously) and submit them as a group
> (with the same referee?).


well, if you could, that would be great. but i predict you'll be lucky to get paper I done to accompany release. it's rare anyway, for anyone to do all the roman numerals at once.

> >The 2MASS Galaxy Catalog I: Overview and Algorithms
> >this would include pretty much what you have in the outline, but only basic
> >"first results" would be given here, such as number and thresholds versus
> >source density, c & r overview, and basic colors, including vs. z.
> > i take it that this would be the MAIN paper with regard to
> GALWORKS and 2MASS


yep.

> >The 2MASS Galaxy Catalog II: Performance in areas with low source density
> > then this is the main science paper


well, sciency results anyway for low densities. the overview is a science paper as well, giving the characteristics of a major science catalog.

> > e. outline objectives of paper and forecast future papers to come
> >** confine forecast to just II and III.
> > i was also referring to the ABELL 262 work of Schneider & Hucrha
> and possibly my work on Abell 3558 (strickly a sci paper demonstrating
> work with 2mass)


don't think this is necessary or fits very well. but if the ref is short, i can't object.

> What we are talking about here is logistics. When to publish and
> what/what_form. One big paper, or three separate papers.
> Three papers means that there will likely be a lag between them
> that can drag on indefinitely (due to unforeseen circumstances and
> to exhaustion from me). On the other hand, you are correct,
> one paper is too unwieldy and will be a some elephant.
>
> What about this: write one big paper, but submit sub-sections
> of it as paper I, II and III. This has the advantage of giving
> continuity between the papers AND they can be submitted
> simultaneously, thus helping the reader locate the papers
> (which really belong togethor). -tj


again, if you can do this, this is great.

i remind you of what you said about my tome on airglow. my next iteration will split it up into 3 memos or so to make it more readable to average person!

To:
skrutski@north.phast.umass.edu schneide@wilt.phast.umass.edu huchra@fang.harvard.edu roc,tchester,jarrett
From: T.Jarrett

Extended Source Guild,
Chester and I have been hatching a plan to build a galaxy cluster catalog based on the 2MASS extended source database/catalog. Our preliminary foray into this field would suggest that indeed we can find clusters and we can predict their redshift as well. The paper I presented at the San Diego AAS touched on the methodology. A more "evolved" description can be found in the link given below (more specifically, it is a proposal to do the job; the Sci team has of course final say on this matter).
The catalog will be similar to what the DPOSS (POSS II people) will generate, but I suspect we will find clusters that they cannot discern (thanks to our infrared eyes). I have an algorithm and software package in place now that can find clusters. The link below describes this system and it presents some case studies of known clusters (ABell 3558, Herc, Coma) as well as a random field chosen from our RTB dataset. The random field contains what I believe to be the first 2MASS cluster (it cannot be found in the literature, but perhaps John Huchra has a secret list somewhere of identified clusters :). Comments welcome. -tj


2MASS comrads,
I would like to open dialogue on planning a series of papers to be submitted to one of the big journals (ApJ or AJ). I believe the time has come that we publish our "early" 2MASS extended source results to contrast/complement the "review" and "preliminary" papers we have been publishing in various conference and seminars/workshops proceedings over the years. With the imminent data release later this summer of a small smackeral of data and of a considerably larger sample next spring, these papers will provide a useful guide/supplement to would-be user of the 2MASS galaxy data set. Given the exceedingly slow turn around for an ApJ paper (we can look forward to at least 8 months of waiting) the series would appear in the journals around the time of the data release.
I envision at least three separate papers (or one large paper divided/published in separate parts) :


1. basic extended source results
2. color-photometric results for a cluster
3. preliminary redshift results

The first paper serves as an "introduction" to the 2MASS extended source database (not unlike the reviews that we have been generating over the years, see e.g. Schneider's nice summary given at the Paris workshop, but with more emphasis on the large area survey results -- we have results over 180 sq. degrees of data fully analyzed). Basic photometric sensitivity results, completeness & reliability and source counts would provide the guts of the results (the latter plot will be unprecidented in the near-IR). This paper will probably serve as the primary "cite" or "reference" paper for future papers by our group and others using 2MASS data. Tom Chester gave a nice poster at the San Diego AAS that basically encapulates this "paper" that needs to be written up for the journals.
The second paper is a more specific topic relating to the photometric/color results for a targeted cluster (e.g., Hercules). I gave a poster at the AAS that might serve nicely as a template for this paper. This kind of paper serves as a more detailed/focused use of the 2MASS data. It could also foreshadow the 2MASS galaxy cluster catalog that we (Jarrett/Chester) have proposed to build.
There may of course be other specific topics that we might want to write up as part of this "early" series of 2MASS extended source science (e.g., Steve might be ready to publish some results on Tully-Fisher).
The third paper might serve as an introduction to the large-scale structure key project buttressed by the massive redshift survey that John is directing. By now we have obtained enough redshift data to gauge our ability to measure the local angular correlations between clusters and superclusters.
Let me be clear that I am not suggesting that we publish prematurely, indeed the key projects themselves have just begun, but rather I believe the "basic" results are in-house and ready to go prime-time (ApJ). With the data release next spring, the "basic" data results will provide a logical supplement to the large data set (which I bet the would-be user will require some time to digest and dissect the rather extensive and complicated information that we will graciously supply:). With the summer months now upon us, it is time to bear down and get these papers out.
Let the flow of dialogue now commence. -tj

i definitely think that you ought to take the lead in writing several papers in order to get some papers out of the tremendous effort you have put into galworks. it would be good to get advice from steve and john, being our galaxy pundits, as to what would be most appropriate.
i assume that john and steve will be the lead authors on the key projects, so there are plenty of first author papers to go around.
some ideas:
we will definitely in the end write up an expl. supp. to 2mass galaxy catalog which will probably be a web doc, and may or may not be published separately. it may be appropriate to publish a "letters" article announcing the 2mass galaxy catalog, with a brief overview of it and its characteristics (numbers, variation with latitude, completeness limits, reliability), that then points the reader to the web doc. this would then be the main scientific literature ref for users of the catalog, but users may simply point to the expl. sup. as is done for iras. i strongly feel that you ought to be the first author on that paper and exp. sup.
_______ note that one really cannot write up the doc for the released catalog until we get there, so it is not practical to think about writing up a mini-exp. sup. 5 months prior to data release. therefore i amend what i said above - the letters article cannot give a brief overview of the catalog, unless we can publish it on a 1-2 month time scale. the letters article can give preliminary results a la my aas paper. title should thus be something like my aas paper:

The 2MASS Galaxy Catalog: First Results
rather than
Overview of The 2MASS Galaxy Catalog
or
The 2MASS Galaxy Catalog
since we simply won't know for sure what will be in the galaxy catalog for some time. thus this paper will only be a reference for the selected items it contains - the main ref has got to be the expl. sup.
there definitely ought to be a scientific overview paper published much like my paper at the first iras conference, which goes more into the scientific content, such as log n / log s numbers, redshift distribution, types of galaxies represented, etc. this probably would not get referenced nearly as much as the exp. supp. or its letters announcement.

your cluster work is entirely separate, and is a major scientific work in its own right along with the key projects. i suggest that you publish preliminary results asap, mentioning in your paper that the catalog is available online as it is being built, with this paper announcing the first clusters found thru ir selection. then people can already start investigating if ir-defined clusters differ from optically defined clusters. making the catalog available as it is being done would be a novelty, which should result in brownie points for you and for the 2mass project. i also don't think this has much danger, since defining the clusters is pretty straightforward, and global analysis is not really needed to validate the cluster catalog.

when it is all done, 3? years from now, you can publish it as an ap.j.supp. i hope by that time the ap.j. is no longer actually publishing long tables, but is simply referencing where to get that online!
again, these are thoughts. comments welcome.