Time Domain DAL/DM/TDIG

[François Bonnarel]

Dear Ada, Marco,

Dear all,


Le 10/07/2017 à 09:22, Marco Molinaro a écrit :
> Dear Ada,
> dear TD/DM/DAL-ers,
>
> you're right, the query by object type (target name, position, class,
> subclass, ...) is definitely a must, but I got the impression that the
> stellar activity is critical for exoplanets (at least).
>
> So, this is a first requirement from my use case: we will need the
> activity value associated with the activity index type. That is, we
> have to leave room for queries that say
>
> stellar activity within these boundaries measured with this index
>
> I think (my case) I could live, e.g. having a source_activity column
> annotated by one UCD among a set that describes the activity index.
> I don't think there exist such UCDs, but I haven't checked either.
> And maybe there exist other solutions.
> Taking the worst case: how can I deal with multiple activity indexes
> describing my host star?
This is a very interesting statement. But I wonder if we can add this 
explicitly in the TimeSeries metadata itself. It's the "Source detailed 
description".

  Isn't that typically a case wher we will query a star catalog for this 
kind of index using TAP and then query TimeSeries around the discovered 
sources ?

So this is probably nice combination of TAP queries and more generic 
time Series queries ?

Apparently this UCD doesn't exist. But it can probably be added in 
phys.magField branch ?

Cheers
François

>
> As for the planets and their characteristics, constraining the search
> on those can be a back end problem, but:
> - planet (confirmed or supposed) existence
> - (stats on?) mass, period, eccentricity
> can be a minimal metadata starting set.
>
> And about discovery methods, that's definitely something they need
> to cross match planets (maybe more for catalogues than time series
> themselves), and it would require a single element from a controlled
> vocabulary. I didn't mean going into the single details of the methods,
> for sure.
>
> Finally, checking on François's metadata blocks, I'd say that
> - object position
> - time sampling characteristics and stats
> - object class (activity augmented)
> have to be in the minimal list.
>
> Cheers,
>      Marco
>
> 2017-07-07 13:51 GMT+02:00 AdaNebot <ada.nebot at astro.unistra.fr>:
>> Dear Marco,
>>
>> Thanks for your input.
>>
>> On 6 Jul 2017, at 14:47, Marco Molinaro <molinaro at oats.inaf.it> wrote:
>>
>> Dear Ada,
>> dear all,
>>
>> regarding the "discovery" item, related to RV Time Series
>> in the exoplanets domain, I had a meeting with people
>> from the GAPS project.
>> (if interested a quick summary can be found here:
>> https://www.asterics2020.eu/dokuwiki/doku.php?id=open:wp4:wp4gapsinaf)
>>
>> The main point I'd like to alert about here (other parts I think
>> are nicely covered by your summary and review) is that a
>> discovery for time series when doing research on exoplanets
>> requires:
>> - host star characterisation, especially stellar activity indexes
>>
>>
>> Regarding the host star characterisation, I think this is in the lines
>> "query by object type”.
>> This is very important not only for exoplanets but for many other scientific
>> cases.
>>
>> - planet(s) ~existence~ and characteristics
>>   [and this may be though because 1 stellar system potentially
>>   means multiple planets]
>>
>> I agree with you
>>
>>
>> And, vice-versa, searching exoplanets having time series attached
>> requires as discovery metadata the search method used (this can be
>> a small vocabulary).
>>
>> I'll try to work on the star/activity/planets part related to the GAPS
>> project, the vice-versa requires other projects with different than
>> spectroscopic RV method to join.
>>
>>
>> There is a list of metadata needed to describe and discover TimeSeries that
>> we came up with during the ASTERICS hackathon meeting,
>> summarised by F. Bonnarel in Shanghai. I have rewritten that list under:
>> http://wiki.ivoa.net/twiki/bin/view/IVOA/DAL_DM_TDIG_ShanghaiSession2017#Asterics_hackathon_report_F_Bonn
>>
>> To my opinion some of the things there are too detailed/complicated, e.g.
>> Fourier coefficients.
>> And I think that we can build a restricted list of minimum requirements
>> based on those.
>> Please, have a look at the list and let me know among those fields which you
>> think are a must.
>>
>> Cheers,
>> Ada
>>
>> Cheers,
>>     Marco
>>
>> 2017-07-04 13:08 GMT+02:00 AdaNebot <ada.nebot at astro.unistra.fr>:
>>
>>
>> Dear All,
>>
>> In Shanghai it was decided that TimeSeries is a scientific priority of the
>> IVOA. Based on the DAL/DM/TDIG session, here is a list of items to be
>> discussed. Please feel free to add any other items you consider relevant to
>> TimeSeries and you would like to discuss:
>>
>> What is TimeSeries data? It is a temporal sequence of measurements
>> containing a time coordinate and a flux (or similar - magnitude) / RV /
>> position / polarisation / number of spots / spectra / images. Light-curves
>> and RV curves dominate the landscape of TimeSeries.
>> Concerning DM: there are models that work for representation of some of the
>> science cases proposed by the SPC.
>>
>> Modified SpectrumDM works fine for light curves with some modifications.
>> The draft TimeSeriesCube serialisation examples work with SPLAT. But there’s
>> still some discussion needed on the model.
>> Feedback from people who have tried both models is appreciated in this
>> respect.
>> Although light-curves and RV curves dominate the landscape of TimeSeries,
>> for which a modified version of SpectrumDM (or a similar for RVs) would
>> work, we should have an extensible model towards other kind of data, perhaps
>> built as a simple derivation/specialization of the SparseCube DM.
>>
>> Discovery: Obscore/EpnCore + TAP could work if the time axis information
>> would be extended. What are the minimum mandatory fields for TimeSeries data
>> to be found by the user? For that collecting science cases is important. A
>> set of minimum data has already been compiled during an ASTERICS meeting.
>> Different communities need to be properly represented. Attending to
>> astronomy meetings is important to hear the astro-community. See the series
>> of meetings under:
>> http://wiki.ivoa.net/twiki/bin/view/IVOA/IvoaVOEvent#Future_Events. Please
>> if you plan to attend any of these meetings or any other related Time Domain
>> meeting it would be useful to know it and to post it on the wiki.
>> Format: Time has to be properly formatted to combine data coming from
>> different surveys. See email from A. Rots (19 May 2017) sent to DM, DAL and
>> TDIG + reference A&A 574, 36 (2015).
>>
>> To keep track these items will be posted on the TDIG wiki, under the
>> TimeSeries section:
>> http://wiki.ivoa.net/twiki/bin/view/IVOA/IvoaVOEvent#Time_Series_Data
>>
>> In particular under: http://wiki.ivoa.net/twiki/bin/view/IVOA/DAL_DM_TDIG I
>> have already written these four items.
>>
>> You can also find a summary of the different contributions in the
>> DAL/DM/TDIG Shanghai session under:
>> http://wiki.ivoa.net/twiki/bin/view/IVOA/DAL_DM_TDIG_ShanghaiSession2017
>>
>> The intention of this email is to start productive discussions on each
>> topic.
>>
>> Thanks!
>> Ada
>>
>>