New stellar population models

[nrnapolita]

Crescenzo provides the new stellar population models, with NIR data

[KiaraSpin]

Group Meeting 18/12: Crescenzo and Mario will work on this after Christmas. Work has to be done on the catalog itself (understand the flagging-priority-, magnitudes limitations, etc). Long process.

[KiaraSpin]

Group Meeting 15/01/2018 Currently two sets of catalog ara available to us: i) weak lens tuned catalog where they drop all the bright galaxies. ii) everything included but to be cleaned.

The first one, is not what we need, cause we will miss a lot of bright galaxies. In the second catalog, there are multiple measurements that must be drop out because of bad photometry, etc. It is not trivial to directly use it. Either we understand how to clean it, or we wait until the official catalog which will be ready in few months.

@Mario:

• PSF in VKING is changing much more that we expected. it was therefore decided to work on single exposures instead of stacked. This way, one can model the PSF night by night, getting the photometry (using r-band as reference) on each and then combine the fluxes. GOOD NEWS: in the catalog we already have the "averaged" photometry for each galaxy.
• Another issue is that you could have the same galaxy observed in different pointings. So again, you could have multiple measurements. -> AI NRN & CT + volunteers : check these things in the catalog

@Crescenzo:

• There is an "issue" related to this for the compact galaxies paper: we need to match the photometrically select UMCGs with the original catalog. CT sent the link to the catalog to Nicola. -> AI NRN : perform the match between the catalogs. This is URGENT ;) We need to understand how large is the contamination by stars.

[KiaraSpin]

GM 29/01 We used these 9-band catalogs already to separate stars and galaxies (using the fact that NIR colors are very different for the two families) in the UCMG paper. This worked very good. The percentage of contaminators is little (few %)

@ctortora has been in contact with people handling the catalog. They 1) confirm that the version we have is the final one (catalog did not change since two/three months) -> Cre can use it for stel. pop. purposes. 2) are going to produce stellar masses themselves.

@mariorpd13 had an email exchange with Maciek (?). Some room for collaboration. He can help us with selecting matched-merged-catalog with a subsample of columns, since he has already tools to extract smaller subsample from the big catalog. We need NIR mags to join with KiDS ones. NICOLA: it would be great to avoid duplication. Let's try to have a "reference catalog" that more than a group can use. -> AI Mario to Crescenzo (Nicola in cc): write an email with the requirements for the catalog and columns we need. -> AI Crescenzo: after receiving the email reply with your requirements so that Mario can close the loop with Majec

[mariorpd13]

Mario and Crescenzo selected the needed columns, email sent to Maciek (waiting for reply)

[KiaraSpin]

GM 12/02 Until now, Crescenzo has always used single-burst models (quite good for low-z ETGs, but not ideal for spirals and higher redshift galaxies). Once we consider also NIR data, we can relax the assumption by fitting colors in nine bands. Inferred stellar pops will be (perhaps) more trustable ... especially in terms of "redshift evolution" Another important addition to our simplistic model is DUST. For now all the galaxies are dust-free. WARNING : Stellar masses (up to redshift 1) are based on SP analysis (SED). It remains to be checked whether with optical bands only the derived stellar masses are trustable. Moreover, galaxy classification might be affected (also dust) too.

[KiaraSpin]

GM 26/02 AI for @ctortora : Send a reminder to Angus to enquire more about what is he doing and what is the stage of stel. pop. analysis...

[KiaraSpin]

GM 16/04 A new project has been open in KiDS by Angus H. Wright (Bonn): KV450: Data curation and mass estimation We need to discuss with him (teleconf planned) to check what exactly they will do and how we can fit into it.

AI @ctortora : coordinate with Angus

[KiaraSpin]

GM 14/05 Are we interested in the KIDS900? If yes, we need to first cross-check with 450 to see if the photometry is the same.

Still need to discuss with Angus.

[KiaraSpin]

GM 26/07 There is a paper coming out from KiDS+VIKING presenting stellar masses obtained by 9 bands. For the moment, mainly due to a lack of communication, we have not been involved in this. HOWEVER it is important now to provide ideas and possible science projects we can lead and scientific products we can provide to them. For instance:

• Follow up on UCMGs
• Stellar population parameters (relaxing the single bursts assumptions)
• DUST (but ...do we have the expertise?)

[ctortora]

Dear all,

just some ideas/comments.

Of course, what we can do from our side is to:

a) do something for galaxy classification using SED fitting; b) They should have best fitted age/Z, we should work on it, running lephare, also with other set of models.... c) people from machine learning group should want to use 9-band photometry for their redshift estimate

Moreover, the products of the KV450 paper should be useful for different projects/topics/scientific items:

1) to select Ultra-compact massive galaxies (better stellar masses); 2) for the size-mass relation, using better masses 3) masses can also be used for other projects (dynamics, lensing, etc. etc.) 4) star/galaxy classification is relevant for compact galaxy project and not only 5) if they have as by-products metallicity and age, these are also useful for many kinds of science topics, allowing to account for the progenitor bias, and we should think about something related to the study of the age-Mstar/Z-Mstar correlations (in terms of redshift and environment) 6) people (Mario) which search for cluster should want to use those data.

Cheers,

   C

Il 26/07/2018 11:55, KiaraSpin ha scritto:

GM 26/07 There is a paper coming out from KiDS+VIKING presenting stellar masses obtained by 9 bands. For the moment, mainly due to a lack of communication, we have not been involved in this. HOWEVER it is important now to provide ideas and possible science projects we can lead and scientific products we can provide to them. For instance:

• Follow up on UCMGs
• Stellar population parameters (relaxing the single bursts assumptions)
• DUST (but ...do we have the expertise?)

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/nrnapolita/KIWI_LSST/issues/2#issuecomment-408044234, or mute the thread https://github.com/notifications/unsubscribe-auth/AgUtQnW5QEyyiYcsHHLm-fq4lSHpYS3Dks5uKZIggaJpZM4QlFdT.

--

Dr. Crescenzo Tortora

/Post-Doc/ Kapteyn Astronomical Institute Postbus 800, 9700 AV, Groningen The Netherlands

Tel: +31 (0)50-3634088 e-mail (1): ctortora@astro.rug.nl e-mail (2): ctortora@na.astro.it web-page: https://www.astro.rug.nl/~ctortora/ https://www.astro.rug.nl/%7Ectortora/

[nrnapolita]

This project has been took over by a student in Zhuhai (Linghua Xie) who is being trained by Crescenzo and myself and with a local supervisor (prof. Baitian Tang). We will update as soon as we have solid results