OiDb User Manual

Revision : 0.1

Date : June 2014

Authors : JMMC oidb Working Group

Table of Content

Introduction

The Optical interferometry Database (OiDb) is a service developed by the JMMC to provide astronomers with a convenient solution to query calibrated optical interferometry data (OIFITS format) as well as regularly-updated observation logs obtained with a wide range of interferometric instruments. It relies on Virtual Observatory standards and tools to increase diffusion and operability. Scientific and technical background of OiDb are described in the paper "Haubois et al., 2014, Proceedings of the SPIE, (to be published)".

OiDb is currently in development and this version is a prototype. User’s feedback is very welcome.

Content of the database

The first function of this database is to diffuse OIFITS1.0 files [1]. Following the IVOA nomenclature [2] (see table below) of calibration levels, the first version of the database will disseminate L2/L3 (reduced and calibrated) data but we also consider offering L1 (uncalibrated) data for the future versions of the service. Astronomers interested in keeping up with recent observations of particular sources can also browse an archive of observation logs (L0 metadata). At the moment, the observation logs provided by the web portal are only available for the CHARA/VEGA instrument.

Data reduction level	Content	What is stored in OiDb	Access Policy
Level 0 (L0)	Raw	Metadata only (meaning Observation logs)	Public
Level 1 (L1)	Reduced uncalibrated	None (for the first version of the Database)
Level 2 (L2)	Reduced calibrated	Data and metadata	Possbility of an embargo period of up to 1 year
Level 3 (L3)	Published	Data and metadata	Public

The home page of OiDb shows an overview of the database content. Concepts of dataPIs and granules that we developed for this project are defined below. This page also allows to directly query data by target name or position or to go to the advanced search form.

dataPIs: how to diffuse data with OiDb (Submit new data)

The dataPI is the person in charge of the scientific program that has led the observations and the subsequent production of the calibrated data that will be diffused on the database. Typically, a dataPI is a data provider who logs in to database to submit his data. The dataPI is responsible for the accuracy and consistency of the data and metadata that will be diffused via the database service. For various reasons, dataPIs may want to temporarily restrict the access to their data. We therefore offer the possibility of an embargo period but at the condition that all metadata always remain public.

Once the dataPI is logged in (click on "Register" for the first use), two main submission options are available: through a form on the web portal or with an XML document. The direct upload of OIFITS files from a local device is not offered for the moment.

The online data submission process (still in progress) is designed in two steps. First, the dataPI submits URLs of OIFITS files that are read and metadata are extracted. The dataPI also fills a form to add the metadata that are not included in the OIFITS keywords and that are important to describe the data (e.g. instrument mode, contact details, etc). Secondly, a submission report is displayed and tells the dataPI if any field is missing or incorrectly filled. She can modify them to complete the submission.

OIFITS files may be alternatively locally processed for metadata extraction and converted to an XML document. This document can be refined with data missing from the source files prior to being uploaded to a special endpoint of the service. Currently this technique is employed for batch processing and uploading the PIONIER L2 dataset to the database. This way of submitting metadata is suitable for large collection of OIFITS files, restricted access files and also non-OIFITS files (provided a suitable parser/extraction tool is written by the dataPI).

Once a set of OIFITS files have been successfully submitted, metadata are stored in tables that follow the ObsCore DM. OIFITS are read, they are not modified by our service so that they remain exactly as they have been uploaded.

The OIFITS is a convenient “container” format but it is not scientifically meaningful per se. For instance, one single file can contain as many observations of many targets at different epochs as one wants. This means the content of an OIFITS file has to be examined and split into relevant granules of information. The following definition of a granule has been adopted for our database:

1 granule = 1 target / 1 night / 1 instrument mode / 1 OIFITS. The metadata of a granule will often represent a subset of an OIFITS metadata.

This implies that several granule might correspond to the same OIFITS file.

Users: how to query data (Search menu)

On the search web portal, the user can query a set of OIFITS files with different parameters: Cone Search[3], observation date, instrument, spectral band, OIFITS collections name and dataPI name. The user can also select the data reduction levels she's interested in. These parameters are then converted into ADQL[4] queries and searches into the database server via an underlying TAP[5] interface.

The results of the search are displayed in a table. Each line of the table represents a granule corresponding to the query. The columns show a selection of the most relevant metadata of our data model. They are chosen so that the user can have a fair idea about the content of the data at one glance. The access_url column provides the user with direct links to download the OIFITS files of her choice. In future versions of the database, the user will be able to configure the columns to display. For more details about a given granule, the user can click on the gear icon located in the first column. The first option “Details” lists all the metadata of the data model (see Figure below). The second option “View in SIMBAD” opens the CDS/SIMBAD page using target_name for the identifier query. Finally, the third option “Paper at ADS” also redirects to the NASA/ADS webpage using the bibcode. The way to display contact details of the dataPI who submitted a given set of OIFITS is being implemented with the creation of dataPI accounts.

When the user downloads a file, she will therefore get one or several granules. This is a consequence of our choice of granularity and our principle of not modifying submitted data. However, the OIFITSExplorer application will soon allow to solve this problemt.

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Users: how to operate data

Also accessible from the gear icon on the result panel, several interoperability options are enhanced using the SAMP6 protocol. The way data is accessed by the user is summarised in Figure 4.

If no SAMP connection has been started, a notification “No SAMP connection” appears. When the user clicks on it, a window pops up and offers to install various applications to analyse the selected OIFITS files via AppLauncher7 (provided by JMMC VO application repository*).

A typical use case would be to query and select some OIFITS on the database web portal, send them to the data-discovery application OIFITSExplorer** and finally to the modelling application LITpro8 (see Figure 5). For more tools, the JMMC/AppLauncher application conveniently allows the user to connect the web portal to many different applications (JMMC apps, TOPCAT, Cassis, Iris, VOPlot, etc). However for the moment, we do not guarantee that OIFITS are correctly supported by all these various VO applications.

Finally, the user can perform operations on all the results returned by the query with the gear icon located on the table header. He can export all the metadata of the DM for all the granules in a VOTable***, download all the OIFITS files at once, or send the whole collections of results for analysis to OIFITSExplorer.

rajouter l'oifits est telecharge

IMPORTANT RULES:

Terms of use

All parties must agree to the following terms before consider using the database:

• To the dataPI's knowledge, all data that are provided to the database are authentic and accurate in the sense that they really are the products of interferometric observations as described by their metadata.

• The user has a commitment to use the data for public astronomical research only. The user has a commitment to get in touch with the dataPI before presenting (in article, conferences) any work including the exploitation of his/her data.

• The archive staff commits in providing help to users and dataPIs to answer questions and fixing issues related to the database project. In the case where archives are uploaded to the database (not url linked) the archive service commits in making sure the data and metadata remain as they were uploaded.

Credits and citations

• If OiDb is useful to your research, please cite it in your publications by adding the following sentence in the acknowledgement section:

This research has made use of the Jean-Marie Mariotti Center \texttt{OiDb} service \footnote{Available at http://oidb.jmmc.fr}.

• All publication based on the data taken from the database must give credits and citations that are decided in agreement with the dataPI.

Feedback

OiDb is currently in development and this version is a prototype. User’s feedback is very welcome.

References

[1] Pauls, T.A., Young, J.S., Cotton, W.D., & Monnier, J.D., “A Data Exchange Standard for Optical (Visible/IR) Interferometry”, PASP, 117, 1255, (2005)

[2] Louys, M., Bonnarel, F., Schade, D., et al., “IVOA Recommendation: Observation Data Model Core Components and its Implementation in the Table Access Protocol Version 1.0”, arXiv:1111.1758, (2011)

[3] Williams, R., Hanisch, R., Szalay, A., & Plante, R., “IVOA Recommendation: Simple Cone Search Version 1.03”, arXiv:1110.0498, (2011)

[4] Ortiz, I., Lusted, J., Dowler, P., et al., “IVOA Recommendation: IVOA Astronomical Data Query Language Version 2.00”, arXiv:1110.0503, (2011)

[5] Dowler, P., Rixon, G., & Tody, D., “IVOA Recommendation: Table Access Protocol Version 1.0”, arXiv:1110.0497, (2011)