Pack: Galaxies Sample Selection Research Object

Description:

This document describes the development of the second Golden Exemplar proposed in Work Package 5: Workflow Astronomy Preservation, and provides discussion about user-driven issues risen in this process and related with general objectives of the Wf4Ever project. The document pertains to the assembly of two Research Objects (RO) packing the digital experiment undertaken for the extraction of a sample of galaxies based on environmental criteria and the calculation of luminosity profiles in several bands for each of the galaxies. The main purpose of deliverable D5.3v2 is to produce the workflows and ROs for the second Golden Exemplar in order to provide feedback based on a user experience for the models and technologies developed in the Wf4Ever project. The workflows and ROs developed may be accessed publicly in the MyExperiment  portal, where the two ROs produced have been uploaded as MyExperiment Packs, as well as in the RODL Wf4Ever Sandbox.

Description:

From a previously selected cube of galaxies residing in a remote database, we provide extragalactic environment parameters for all galaxies sample.

This workflow takes as input the path of the tabular *.pckl Python pickle dataset created in the previous workflow, as well as the database connection settings and several criteria on how to filter the potential companions of the target galaxies. It provides a file with the SDSS identifiers of each target galaxy of the sample, environmental estimators and radius where the 10th companion has been found. The workflow looks for potential companions in radius ranging from 3Mpc to 11Mpc, with a step of 1Mpc. The user may modify these numbers at the input stage, as well as several limits and ranges needed in the filtering process. As in the previous workflow other provided input values are the Working Path of the digital experiment and the database connection settings: hostname, login and password.

Execution environment The first requirement to run the workflows provided by both ROs is Taverna Workbench2 2.4 or higher. AstroTaverna (Taverna plugin) is also needed in order to get functionalities related with Virtual Observatory web services queries and management of standard VOTable data formats. In general, the execution environment is a Linux distribution including Python4 2.x and a bash shell, with psycopg and numpy Python packages. Access to a PostgreSQL database storing the physical parameters provided by SDSS is also needed; a dump file of database may be downloaded from the AMIGA web server and in order to be deployed and accessible from a local execution environment.

Description:

This document describes the "Galaxies Sample Selection" Research Object

Description:

This workflow saves a tabular *.pckl Python pickle dataset in the local file system, containing values calculated on physical parameters associated to potential companions of a sample of target galaxies. These original physical parameters are extracted from a postgreSQL database, containing information of all galaxies covered by the SDSS spectroscopic survey. The workflow first access the external database located in the AMIGA server and selects the target galaxies from the sample (those having spectroscopic redshift between 0.03 and 0.1). It then creates a tabular gridded datacube with values associated to potential neighbours. These values are calculates for each point of a 3D space defined by the axes: magnitude in r band, photometric redshift and sigma level of detection. The input default values to build the parameterised datacube are:

- 14.5<mr><22.5><z><0.11><sigma><3.2>

Auxiliary function libraries and scripts are also copied in local file system, and the PYTHONPATH environmental variable is set to a value provided by the user as the Working Path of the digital experiment. Other user provided input values are the database connection settings: hostname, login and password.

Execution environment

The first requirement to run the workflows provided by both ROs is Taverna Workbench2 2.4 or higher. AstroTaverna (Taverna plugin) is also needed in order to get functionalities related with Virtual Observatory web services queries and management of standard VOTable data formats. In general, the execution environment is a Linux distribution including Python4 2.x and a bash shell, with psycopg and numpy Python packages. Access to a PostgreSQL database storing the physical parameters provided by SDSS is also needed; a dump file of database may be downloaded from the AMIGA web server and in order to be deployed and accessible from a local execution environment.