DM Science User Interface UML Use Case Model
Draft
: LDM-244 Latest Revision Date 10/29/2013
DM Science User Interface UML Use Case Model
Draft
: LDM-244 Latest Revision Date 10/29/2013
Large Synoptic Survey Telescope (LSST)
DRAFT
| Data Management Science User Interface UML Use Case Model | ||
| Schuyler Van Dyk, Jeff Kantor | ||
| LDM-244 | ||
| Latest Revision Date: October 29, 2013 | ||
| Change Record | ||
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Date
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Description
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Owner name
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0
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10/18/2013
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Initial installation (EA DM Apps: rev 1.154)
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R Allsman
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10/29/2013
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Draft version changes. (EA DM Apps: rev 1.157)
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R. Allsman
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Table of Contents
Change Record i
| 1 | Introduction 1 |
| 2 | Science Usage and Analysis 1 |
| 2.1 | Representative Science Use Cases 2 |
| 2.1.1 | Science User 7 |
| 2.1.2 | Determine the Properties of a Luminous Red Nova at Redshift 0.02 7 |
| 2.1.3 | Find Signature of Baryon Acoustic Oscillations 9 |
| 2.1.4 | Locate RR Lyrae Stars in a Galactic Halo Stream 13 |
| 2.1.5 | Study the Formation Mechanisms of SDOs versus KBOs 16 |
| 2.1.6 | Analyze Color-Color Diagram 18 |
| 2.1.7 | Analyze Color-Magnitude Diagram 19 |
| 2.1.8 | Analyze Light Curve of Luminous Red Nova 20 |
| 2.1.9 | Cleanse the color-magnitude diagrams 21 |
| 2.1.10 | Compute Auto Power Spectrum 22 |
| 2.1.11 | Compute Cross Power Spectrum 22 |
| 2.1.12 | Correct for Survey Systematics 23 |
| 2.1.13 | Create Cleaned Color-Magnitude Diagram 23 |
| 2.1.14 | Create Color-Color Diagram 24 |
| 2.1.15 | Create Color-Magnitude Diagram 25 |
| 2.1.16 | Create Corrected Color-Magnitude Diagram 27 |
| 2.1.17 | Create Diagram of One Property Versus Another 28 |
| 2.1.18 | Create Histogram 28 |
| 2.1.19 | Create Power Spectrum Template 28 |
| 2.1.20 | Determine Angular Diameter Distance As a Function of Redshift 29 |
| 2.1.21 | Examine Coadd Image of Host Galaxy of Transient Event 29 |
| 2.1.22 | Federate Cleaned Catalog Query with External Catalog 30 |
| 2.1.23 | Filter out AstroObjects with proper motion 31 |
| 2.1.24 | Fit Auto Power Spectrum 31 |
| 2.1.25 | Fit Phase Function to Sources 32 |
| 2.1.26 | Obtain photometry from the AstroObject Catalog 32 |
| 2.1.27 | Perform Fitting of Object Color Distribution 33 |
| 2.1.28 | Select AstroObjects of Given Period 33 |
| 2.1.29 | Separate Sample Into Photometric Redshift Bins 34 |
| 2.1.30 | Visualize Sample by Photometric Redshift 34 |
| 2.1.31 | Visualize and Analyze Cleaned Color-Magnitude Diagram 35 |
| 2.1.32 | Will the AstroObject Catalog have a column flag for AstroObjects with proper motion? 35 |
| 2.2 | Science User Interface 35 |
| 2.2.1 | Basic Archive Access 36 |
| 2.2.2 | Data Analysis and Visualization 44 |
| 2.2.3 | Alert Subscription 53 |
| 2.2.4 | User Assistance/Help Desk 58 |
| 2.2.5 | User Workspace Management 58 |
Data Management Science User Interface UML Model
1 | |
| Introduction | |
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The Purpose of this Document is to define the Use Case Model for the LSST Data Management System (DMS) Science User Interface. This document is generated from Enterprise Architect.
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2 Science Usage and Analysis
WBS 02C.05 Science User Interface and Analysis Tools
This WBS element is a summary element that contains the software, tools, and user interfaces specifying the Science User Interface and Analysis Tools which will support the following features:
- Provide coherent and intuitive mechanisms for scientists to access the data products (images, catalogs, alerts);
- Provide mechanisms for scientist to analyze and visualize the data sets and identify data subsets of interest;
- Provide mechanisms for scientists to download, export or import data subsets of interest to alternative storage locations or into analysis environments;
- Provide a mechanism for scientists to store, manage and manipulate large data subsets of interest using Data Center resources;
- Facilitate federation of the data products with external data;
- Serve documentation about the DMS and data products;
- Provide automated and human assistance in working with the DMS and data products;
- Enable scientists to develop analytical codes by reusing existing DMS codes and integrating externally developed codes;
- Execute the analytical codes on local or external platforms;
- Capture and analyze the results of those codes.
NOTE: The UML for this WBS element is in development at this time.
2.1 Representative Science Use Cases
Figure 1: Determine the Properties of a Luminous Red Nova at Redshift 0.02
Figure 2: Find Signature of Baryon Acoustic Oscillations
Figure 3: Locate RR Lyrae Stars in a Galactic Halo Stream
Figure 4: Study the Formation Mechanisms of SDOs versus KBOs
2.1.1 Science User
2.1.2 Determine the Properties of a Luminous Red Nova at Redshift 0.02
Description:
The scientific goal is to discover the properties and nature of a luminous red nova (LEN) at redshift 0.02 discovered by LSST. This use case is from one of the four main Science Themes for LSST, Exploring the Transient Optical Sky. Luminous red novae (LRNe) are rare and currently not well understood in the local Universe. They typically have absolute magnitudes in the range of about -10 to -14. It is currently unknown what are the progenitors of these objects as a class, although it is speculated that at least one member of this class may have come about from a stellar merger. LRNe "fill the gap" between classical novae and faint core-collapse supernovae. They tend to vary in brightness over tens to hundreds of days. LSST should discover up to about 3400 such events per year.
This particular LRN first appears as Transient Alert . The Science User subscribes to the Alert Category including LRNe. It is at a distance of nearly 100 Mpc (redshift ~ 0.02), putting it near the faint limit at r of an individual calibrated exposure . The Science User wants to obtain all of the limits on detection of the DIA Source prior to discovery from the Forced Source Catalog and then obtain from the Source Catalog all of the available photometry in all bands for the LRN, in order to develop light and color curves for the object. These curves will be analyzed using several models for the properties of LRNe, in order to reveal the object's true nature.
The Science User will also retrieve the time sequence of calibrated exposure s in order to display a movie of the time sequence and the apparitions of the DIA Source in the exposures.
The Science User will also examine the deep coadded exposure to study the nature of the host galaxy of the LRN.
The Science User will subsequently annotate the history of this Transient Alert .
Basic Course:
User Invokes: 'Retrieve Alerts' to obtain the Transient Alert of the newly-discovered LRN. The alert will consist of a data stream providing positional and brightness information on the new DIASource . The system will also provide a postage stamp image of the source.
System Invokes: 'Retrieve Postage Stamp'
User Invokes: 'Extract Time Series for Objects' to obtain all apparitions of the new source at its reported sky coordinates from both the SourceCatalog and ForcedSource Catalog , in all available bands.
System invokes: 'Query Source Catalog'.
System invokes: 'Query ForcedSource Catalog'.
User invokes: 'Save Query Result to User Workspace' to save the resulting data for further analysis.
User Invokes: 'Analyze Light Curve of Luminous Red Nova.' The Science User analyzes the query result saved to the User Workspace by displaying the light curve for the source.
User Invokes: 'Display Light Curve for Object' to view the 2D representation of brightness (magnitude) versus time for the new DIASource in each of the available bands, in order to study the nature of the variability for the new source.
User Invokes: 'Examine Coadd Image of Host Galaxy of Transient Image'. The Science User will examine the position of the new DIASource in a deep Coadd exposure, in order to determine where the source is relative to physical features (spiral arms, dust lanes, star-forming regions, etc.) in its host galaxy, to attempt to place constraints on the nature of the source's precursor star.
User Invokes: 'Query Image Archive' and the system returns the Deep Coadd Exposure
User Invokes: 'Extract Time Sequence of Exposures'. The Science User wishes to view a 'movie' of all of the calibrated exposures in which the new DIASource is detected, as a 2D representation of the previously-viewed light curve.
System Invokes: 'Query Image Archive' and returns the Time sequence of calibrated exposures for the DIASource .
User Invokes: 'Blink/Display Movie of Multiple Images' to view this time sequence as a 'movie'.
The Science User will then write an oft-cited manuscript on the results for the luminous red nova.
Alternate Course: N/A.
2.1.3 Find Signature of Baryon Acoustic Oscillations
Description:
The scientific goal is to find the signature of baryon acoustic oscillations (BAO) in the entire LSST dataset. This use case is from one of the four main Science Themes for LSST, Constraining Dark Energy and Dark Matter. LSST will observe ~1000 Gpc3 of the universe, nearly a factor of 100 more than SDSS. Detection of BAO is "the new precision cosmology probe," allowing accurate and robust measurement of the properties of Dark Energy. Specific properties include Omega_matter, baryon fraction, sigma_8, and galaxy bias factor, based on the observed angular power spectrum, for a fixed Hubble constant and scalar index of primordial fluctuations. This is an ambitious, but supportable, project using the LSST data.
This use case emulates what Blake et al. (2007, MNRAS, 374, 1527) did with SDSS, and what Seo et al. (2012, ApJ, 761, 13), and Ho et al. (2012, ApJ, 761, 14) did with SDSS-III, using a sample based on photometric redshifts.
In this use case, the Science User performs a query of the AstroObject Catalog , extracting AstroObjects that meet specifications based on magnitude and color, primarily in gri, and star-galaxy separation, within a limited photometric redshift range, e.g., 0.45 < z < 0.65. The aim is to isolate luminous red galaxies, which possess the most robust photo-z's, due to the simplicity of their spectral energy distributions. Due to the uncertainties in the photo-z's, one cannot recover the evolution of the Hubble constant with z, H(z); there is also additional damping of the BAO, due to projection effects and difficulty in applying BAO reconstruction.
Once the query results are finely honed based on the color, magnitude, and star-galaxy separation, the Science User attempts to correct for the survey systematics, including residual stellar contamination, sky brightness variations, seeing variations, any color and magnitude offsets within the survey, extinction along the line-of-sight, and survey coverage, for which available survey coverage/depth masks need to be employed. Then, the sample is separated into bins by photo-z. Since LSST photo-z precision is to be 1%, the bin z-intervals can be quite small, e.g., Delta(z)=0.01 or 0.02. The slices or bins of the sample can be visualized in 3D to see the actual clustering of the galaxies.
Next, the auto and cross angular power spectra are computed using, e.g., quadratic estimators. One could combine the auto power spectra between z bins using covariance matrices. The cross power spectrum determines the covariance between different z bins and provides a useful analytical cross-check. An auto power spectrum template is then created, as a 2D projection of the 3D power spectrum, and is corrected for redshift-space distortions, assuming a galaxy bias; this is generally done using a "training set" based on spectroscopic z's. One needs to mimic within the template the nonlinear evolution of the BAO due to structure growth.
The Science User then measures the location of the BAO features by fitting the auto power spectrum with the template power spectrum. The observed locations of the BAO peaks in the power spectrum are determined by the angular diameter distance at each z, i.e., D_A(z), which is where the cosmological factors exist.
Basic Course:
User invokes: 'Obtain photometry from the AstroObject Catalog ', specifying appropriate ranges in magnitude, color, photometric redshift, and star-galaxy separation, and extracting AstroObjects that meet these specific ranges in properties.
User invokes: 'Extract Objects with User-Specified Properties'.
System invokes: 'Query AstroObject Catalog' in order to acquire the dataset matching the Science User 's specification which return AstroObjects and number of AstroObjects.'
User invokes: 'Save Query Result to User Workspace' to save the resulting data for further analysis.
User invokes: 'Create Color-Magnitude Diagram' specifying the data saved in the workspace and appropriate setup options in order to display the query results in both color and magnitude.
User invokes: 'Create 2D Display of Catalog Query Result'.
User invokes: 'Analyze Color-Magnitude Diagram' to select interactively with the graphical display AstroObjects in a certain color range that are also within a certain magnitude range. The aim is to isolate luminous red galaxies which are in a limited magnitude and color range.
User invokes: 'Save Subset of Query Result to User Workspace'.
User invokes: 'Create Color-Color Diagram' specifying the data in the workspace and appropriate setup options in order to display the query results in one color versus another color.
User invokes: ' Create 2D Display of Catalog Query Result'.
User invokes: 'Analyze Color-Color Diagram' to further refine interactively with the graphical display the color selection of the AstroObjects of interest, i.e., luminous red galaxies, which exist only in a limited color range in the combinations of the various bands. The Science User then saves the result of this analysis to the User Workspace.
User invokes: 'Save Subset of Query Result to User Workspace' to save result of this analysis.
User invokes: 'Correct for Survey Systematics' to correct the query result subset for effects, such as residual stellar contamination, sky brightness variations, seeing variations, any color and magnitude offsets within the survey, extinction along the line-of-sight, and survey coverage , for which available survey coverage/depth masks need to be employed.
User invokes: 'Use Survey Coverage Masks'.
User invokes: 'Separate Sample Into Photometric Redshift Bins' to arrange the query result subset either into separate files representing each bin or by sorting the subset in order of photometric redshift.
User invokes: 'Visualize Sample by Photometric Redshift' to view the binned sample in 3D ( sky position versus photometric redshift), which would reveal the clustering of the galaxies.
User invokes: 'Create 3D/4D Display of Catalog Query Results'.
User invokes: 'Compute Auto Power Spectrum' of the query result subset. This step and all others below can be performed either in the User Workspace or external to the SUI.
User invokes: 'Compute Cross Power Spectrum' of the query result subset to determine the covariance between different redshift bins, providing a useful analytical cross-check on the overall results of this work.
User invokes: 'Create Power Spectrum Template' as the 2D projection of the 3D auto power spectrum, generally done using a spectroscopic redshift "training set", and then corrected for redshift-space distortions, assuming a galaxy bias.
User invokes: 'Fit Auto Power Spectrum', measuring the location of the BAO features by fitting the auto power spectrum with the template power spectrum.
User invokes: 'Determine Angular Diameter Distance As a Function of Redshift'. The observed locations of the BAO peaks in the power spectrum are determined by the angular diameter distance at each z, i.e., D_A(z).
The Science User infers the various cosmological factors from the angular diameter distance and then writes an oft-cited manuscript on the results.
Alternate Course: N/A
2.1.4 Locate RR Lyrae Stars in a Galactic Halo Stream
Description:
The scientific goal is to constrain the halo gravitational potential for the Milky Way. This use case is from one of the four main Science Themes for LSST, Mapping the Milky Way. This can be accomplished by discovering and measuring the kinematics for Galactic streams in the halo, moving under the influence of the potential. Measuring accurate distances to these streams is crucial, which can be accomplished by locating the RR Lyrae variables within the streams. These variables are a well-studied distance indicator. By understanding the nature of the streams, we may also be able to analyze early Universe structures falling into the Milky Way potential for the first time.
Basic Course:
User invokes: 'Obtain photometry from the AstroObject Catalog ' specifying the appropriate options for the search query in order to obtain photometry in all bands of a certain quality for the AstroObjects in a rectangular field centered on the position of the Galactic Halo stream.
User invokes: 'Extract AstroObjects with User-Specified Properties' in order to define the search region specified by the Science User.
System invokes: 'Query AstroObject Catalog' in order to acquire the dataset matching the Science User's specification and returns AstroObjects and number of AstroObjects.
User invokes: 'Save Query Result to User Workspace' to save the resulting data for further analysis.
User invokes:' Create Color-Magnitude Diagram' specifying the data saved in the workspace and appropriate setup options in order to display the query results in both color and magnitude.
User invokes: 'Create 2D Display of Catalog Query Result'.
User invokes: 'Analyze Color-Magnitude Diagram' to select interactively with the graphical display AstroObjects in a certain color range that are also within a certain magnitude range. The RR Lyrae stars exist only within a limited range in brightness, hence, their use as a 'standard candle.'
User invokes: 'Save Subset of Query Result to User Workspace' to save the result of this analysis.
User invokes: 'Create Color-Color Diagram' specifying the data in the workspace and appropriate setup options in order to display the query results in one color versus another color.
User invokes: ' Create 2D Display of Catalog Query Result'.
User invokes: 'Analyze Color-Color Diagram' to further refine interactively with the graphical display the color selection of the AstroObjects of interest, i.e., the RR Lyrae stars in that field, which exist only in a limited color range in the combinations of the various bands.
User invokes: 'Save Subset of Query Result to User Workspace' to save the result of this analysis to the User Workspace.
User invokes: 'Select AstroObjects of Given Period' to interactively with the graphical display isolate from the sample those AstroObjects having variability periods consistent with expectation for RR Lyrae stars. The Science User provides constraints to the system on the range of periods to be extracted from the sample.
User invokes: 'Extract Times Series for Objects' to select AstroObjects within a range of variability parameters specified by the user.
User invokes: 'Display Light Curve for Object' to view the 2D representation of brightness (magnitude) versus phase (time) of variability for the selected AstroObjects consistent with the expected period of variability for RR Lyrae stars, to validate that the selected AstroObjects are RR Lyrae stars in the field of interest.
User invokes: 'Create 2D Display of Catalog Query Results'.
User invokes: 'Save Subset of Query Result to User Workspace' to save the result of this analysis.
The Science User will subsequently use the apparent brightness of the subsample of selected RR Lyrae stars, once corrected for foreground extinction, to determine the distance of the stars and, therefore, the distance to the Galactic halo stream. With the distance known to the stream, the Science User can use models to constrain the gravitational potential of the Galactic halo, and write an oft-cited manuscript on the results.
Alternate Course:
* No data are available for the field of interest from the AstroObject Catalog .
2.1.5 Study the Formation Mechanisms of SDOs versus KBOs
Description:
The scientific goal is to determine the formation mechanisms of scattered disk objects (SDOs) versus traditional Kuiper Belt Objects (KBOs) in the Solar System. This use case is from one of the four main Science Themes for LSST, Taking an Inventory of the Solar System. Both types of objects are found at large semi-major axes (a), i.e., distance from the Sun, beyond the orbit of Neptune. Examining the size and color distributions of these two classes of objects will provide valuable insight into their formation mechanisms: KBOs are thought to have formed in situ at their current a, while SDOs were likely perturbed by planetary migration.
In this use case, the Science User performs a query of the SSObject Reference Catalog and the SSObject Catalog for all SSObjects of a certain range in orbital semi-major axis (a) and inclination (i). The Science User then plots eccentricity (e) versus a and i versus a for the query result, to distinguish the SDOs from the KBOs. The Science User then determines the color distribution for both object types with a histogram. The Science User then analyzes the light curves for both objects, both in amplitude and phase. This requires fitting phase functions to the variability of objects of both types, which could be a Level 3 activity, although the results of which could be fed back into the SUI. The Science Use r defines the phase function based on the solar elongation for each object. The residuals in the variability, after removing the phase function fit, results in light curves for the SSObjects . The phase curve provides information on an object's albedo, while the light curve provides information on its rotation and roundness. (A small period of variability implies an irregularly-shaped object.) The Science Use r could, in a final step, display the tracks of the various SDOs and KBOs on calibrated exposures to examine their motions.
Basic Course:
User invokes: 'Extract SSObjects with User-Specified Properties' to search for and obtain all SSObjects of a certain range in orbital semi-major axis and inclination.
System invokes: 'Query the SSObject Reference Catalog'.
System invokes: 'Query the SSObject Catalog' which returns the SSObjects
User invokes: 'Save Query Result to User Workspace' to save the resulting data for further analysis.
User invokes: 'Create Diagram of One Property Versus Another' to plot eccentricity versus semi-major axis and inclination versus semi-major axis for the SDOs and KBOs returned as the query result.
User invokes: 'Create 2D Display of Catalog Query Result'.
User invokes: 'Create Histogram' to plot the color distribution including both object types with a histogram.
System invokes: 'Create 2D Display of Catalog Query Result'.
User invokes: 'Perform Fitting of Object Color Distribution' to fit an analytical function to the histogram to distinguish the distributions of SDO and KBO colors. The two samples can be isolated interactively on the histogram and saved as separate files to the User Workspace.
User invokes: 'Save Subset of Query Result to User Workspace'.
User invokes: 'Extract Time Series for Objects' from the DIASource Catalog and Forced DIASource Catalog for both the SDO and KBO samples.
System invokes: 'Query Source Catalog'.
System invokes: 'Query ForcedSource Catalog'.
User invokes: 'Save Query Result to User Workspace' to save the resulting data for further analysis.
User invokes: 'Fit Phase Function to Sources', based on the solar elongation for each object. The residuals in the variability, after removing the phase function fit, results in light curves for these SSObjects . The resulting phase curve provides information on an object's albedo.
User invokes: 'Display Light Curve for Object' to view the 2D representation of brightness (magnitude) versus phase (time) of variability for the selected SSObjects .The light curve provides information on an object's rotation and roundness.
User invokes: 'Display Tracks/Tracklets for Solar System Objects'. The goal of this final step is to display the tracks of the various SDOs and KBOs on calibrated exposures to examine their motions.
System invokes: 'Query Image Archive'.
Alternate Course: N/A.
2.1.6 Analyze Color-Color Diagram
DESCRIPTION: The Science User employs analytical tools and comparison models to interpret the data displayed in a color-color diagram .
BASIC COURSE:
Science User
invokes the use case "Create Color-Color Diagram"
obtains LF of unresolved galaxies
cleans faint end of CCD (statistically) using the LF of unresolved galaxies
runs isochrone fitting algorithm
derives ages, metallicities, distance, reddening for stellar populations
ALTERNATE COURSES:
System returns "Error" screen if isochrone fitting algorithm fails to find a solution
2.1.7 Analyze Color-Magnitude Diagram
DESCRIPTION: The Science User employs analytical tools and comparison models to interpret the data displayed in a color-magnitude diagram .
Basic Course:
The Science User
invokes Create Color-Magnitude Diagram .
The Science User then uses tools and models, e.g., isochrones or stellar evolutionary tracks, to determine properties of the data, or subsets of the data, such as the ages of the stellar populations, metallicities of the stellar populations, or interstellar extinction of the stellar populations evident in the diagram.
Alternate Course: N/A.
2.1.8 Analyze Light Curve of Luminous Red Nova
Description: The Science User wants to obtain all of the limits on detection of the DIA Source prior to discovery from the Forced Source Catalog and then obtain from the Source Catalog all of the available photometry in all bands for the LRN, in order to develop a light curve for the object. The curve will be analyzed using several models for the properties of LRNe, in order to reveal the object's true nature.
Basic Course:
User Invokes: Extract Time Series for Objects, from the Source Catalog and ForcedSource Catalog.
System Invokes: Query Source Catalog
System Invokes: Query Forced Source Catalog
User Invokes: Save Query Result to User Workspace
User Invokes: Display Light Curve for Object
Alternate Course:
No prior detections exist for this source in the Source Catalog.
2.1.9 Cleanse the color-magnitude diagrams
Description:
To “cleanse” the color-magnitude diagrams of Galactic foreground stars, the Science User must analyze the proper motions of objects in the large field. This would either entail filtering on objects flagged as proper-motion objects in the AstroObject Catalog (which would be easy, if the Level 2 products have this flag from the pipeline) or querying each of the DR Catalogs separately, to determine which objects have significant offsets in their centroids from one release to the other (more difficult). This all depends on what the data products provide. If the former, then
Basic Course: the Science User eliminates foreground sources as part of the query, i.e., selecting all AstroObjects in the AstroObject Catalog in the field not flagged as possessing measurable proper motion.
Invoke: Filter out AstroObjects with proper motion.
Alternate Courses: The Science User queries each of the DR AstroObject Catalogs. In the User Workspace, user scripts or software would be invoked to determine positional offsets, object for object, in the field as a function of year. (It could be possible that an Analysis Tool could be developed at some point to do this as part of the User Workspace environment.) Any object with positional displacement in one DR relative to the previous DR(s) greater than a certain tolerance or threshold would be flagged by the Science User and subsequently removed from the AstroObject Catalog query output.
The position variations or AstroObject movement vectors could subsequently be visualized for inspection (requirement 1.37.4).
2.1.10 Compute Auto Power Spectrum
Description: The Science User computationally derives the angular power spectrum, which measures the power of a particular angular direction and is a projection of the spatial power spectrum, P(k,z), of fluctuations in the background at different redshifts, z, where k is a co-moving wavenumber. The auto power spectrum is the Fourier transform of the two-point autocorrelation function. Given a random galaxy in a location, the correlation function describes the probability that another galaxy will be found within a given distance.
Basic Course: The Science User computes the auto angular power spectrum from a sample of AstroObject Catalog data.
Alternate Course: N/A.
2.1.11 Compute Cross Power Spectrum
Description: The Science User computationally derives the angular power spectrum between different redshift slices i and j for a given cosmological model. The cross power spectrum is the Fourier transform of the cross-correlation function.
Basic Course: The Science User computes the cross angular power spectrum from a sample of AstroObject Catalog data.
Alternate Course: N/A.
2.1.12 Correct for Survey Systematics
Description: The Science User applies a correction to the results of a query of the AstroObject Catalog for various survey-specific factors, e.g., sky brightness variations, seeing variations, survey coverage variations, etc. For survey coverage variations, this could come in the form of masks built on knowledge of the survey coverage or survey depth.
Basic Course:
Invoke Acquire Survey Coverage Masks
Alternate Course: No correction for survey effects is required.
2.1.13 Create Cleaned Color-Magnitude Diagram
DESCRIPTION:
Create Cleaned Color-Magnitude Diagram
BASIC COURSE:
User requests Cleaned Color-Magnitude Diagram
System
obtains Luminosity Function (LF) of unresolved galaxies
cleans faint part of the CMD (statistically) using the LF of unresolved galaxies
displays the Create Color Magnitude Result Screen which contains the URL pointer to the files and/or diagram with the CMD
ALTERNATE COURSES:
System displays Create Color Magnitude Error Screen, if LF not found
2.1.14 Create Color-Color Diagram
DESCRIPTION: This activity uses the Data Analysis and Visualization Tool to produce a color-color diagram , a 2D plot of one color versus another color for AstroObjects from the AstroObject Catalog .
BASIC COURSE:
User specifies on Color Color Input Screen:
sky region boundaries
colors for X- and Y- axes
star certainty percent
return format (ASCII file, FITS table, diagram, etc)
System:
validates user input parameters
queries the Object Catalog to produce a ColorColorTable that satisfies the contraints for objects whose classification is stellar at >= the star certainty percentage
generates the requested output format from the ColorColorTable
displays the Color Color Result Screen which contains the URI pointer to the files and/or color-color diagram
ALTERNATE COURSES:
System displays "Incorrect input" screen, if
sky region boundaries are not provided, or are incorrect
axes are not defined
System warns if the sky region is too large (too many sources)?
2.1.15 Create Color-Magnitude Diagram
DESCRIPTION: This activity uses the Data Analysis and Visualization Tool to produce a color-magnitude diagram , a 2D plot of magnitude versus color for AstroObjects from the AstroObject Catalog .
BASIC COURSE:
Invokes: Create 2D Display of Catalog Query Result
User specifies on the Create Color Magnitude Input Screen
sky region boundaries
color and magnitude for CMD
star certainty percent
return format (ASCII file, FITS table, diagram, etc)
System
validate user input parameters
queries the Object Catalog to produce a ColorMagnitudeTable that satisfy the constraints for objects whose classification is stellar at equal or greater than the star certainty percent
generates the requested output format from the ColorMagnitudeTable
displays the Color Magnitude Result Screen which displays the graphic and optionally contains the URI pointer to the files
ALTERNATE COURSES:
System displays Create Color Magnitude Error Screen, if
sky region boundaries are not provided, or are incorrect
CMD axes are not defined
System displays Sky Region Too Large Screen (too many sources)?
2.1.16 Create Corrected Color-Magnitude Diagram
DESCRIPTION:
Create Corrected Color-Magnitude Diagram
BASIC COURSE:
User requests a Corrected Color-Magnitude Diagram from a given ColorMagnitudeTable
System
invokes Create Color-Magnitude Diagram
get CMD Analysis Policy from Policy Library
bin stellar photometry by magnitude
correct raw ColorMagnitudeTable:
collect completeness data from Detection Efficiency Catalog
statistically correct raw Color-Magnitude table
generates the requested output format from the ColorMagnitudeTable
displays the Corrected CMD Result Screen which contains the URL pointer to the files and/or diagram with the CMD
ALTERNATE COURSES:
displays Corrected CMD Error Screen on error
2.1.17 Create Diagram of One Property Versus Another
DESCRIPTION: This activity uses the Data Analysis and Visualization Tool to produce a diagram, a 2D plot of one catalog column versus another for AstroObjects from the AstroObject Catalog or SSObjects from the SSObject Catalog .
2.1.18 Create Histogram
DESCRIPTION: This is a Data Analysis and Visualization Tool to produce a two-dimensional representation of the probability (number) distribution of a continuous variable, usually a column in the result of a query of the AstroObject Catalog.
BASIC COURSE: The Science User specifies the range of data within a column from the query result and the binning of those data to plot in this visualization tool. The Science User can interact with the plot and further refine its appearance within the tool.
ALTERNATE COURSE: N/A.
2.1.19 Create Power Spectrum Template
Description: The Science User creates a template angular power spectrum of the autocorrelation function, using a "training set" of galaxies derived from a spectroscopic-redshift survey, for which the actual redshift distribution is accurately known, assuming a given cosmology.
Basic Course: The Science User builds the template power spectrum and fits it to the actual angular power spectrum from the larger sample of AstroObjects (galaxies) for which there are photometric redshifts.
Alternate Course: N/A.
2.1.20 Determine Angular Diameter Distance As a Function of Redshift
Description: The observed location of the baryon acoustic oscillation (BAO) peaks in a power spectrum of a galaxy sample is determined by the angular diameter distance, D_A(z), at each redshift.
Basic Course: The Science User fits the angular power spectrum for the galaxy sample and derives actually the ratio of the angular diameter distance to the sound horizon radius. The Science User must then assume a constraint on the sound horizon radius from, e.g. WMAP, to determine the value of D_A(z). This value depends explicitly on the values of various cosmological parameters.
Alternate Course: N/A.
2.1.21 Examine Coadd Image of Host Galaxy of Transient Event
Description: The Science User obtains a Deep Coadd Exposure containing the position of the host galaxy of an extragalactic DIA Source . The science goal is to determine the global properties of the galaxy, the nature of the immediate environment of the transient, in order to put the event in the context of its host and, e.g., its star formation properties, etc.
Basic Course:
System Invokes: Query Image Archive
System Returns: Deep coadd exposure
Science User then examines the deep coadd exposure at the location of the transient.
Alternate Course:
A coadd exposure does not yet exist for this field.
2.1.22 Federate Cleaned Catalog Query with External Catalog
Description: The results of an AstroObject Catalog query can be federated with external catalogs (requirement 1.22).
Basic Course: The Science User federates the results of removing proper-motion AstroObjects from the query of the AstroObject Catalog with an external catalog.
Alternate Course: The external catalog does not have entries which match with the query results from the AstroObject Catalog.
2.1.23 Filter out AstroObjects with proper motion
Description: The Science User filters out AstroObjects flagged as proper-motion AstroObjects, or containing a proper motion column entry, in the AstroObject Catalog.
Basic Course: The Science User selects all AstroObjects in the AstroObject Catalog not flagged as AstroObjects possessing proper motion.
Invokes: Save Cleaned Query to User Workspace.
Alternate Course:The Science User queries each of the DR AstroObject Catalogs. In the User Workspace, user scripts or software would be invoked to determine positional offsets, object for object, in the field as a function of year. (It could be possible that an Analysis Tool could be developed at some point to do this as part of the User Workspace environment.) Any object with positional displacement in one DR relative to the previous DR(s) greater than a certain tolerance or threshold would be flagged by the Science User and subsequently removed from the AstroObject Catalog query output.
2.1.24 Fit Auto Power Spectrum
2.1.25 Fit Phase Function to Sources
Description: A fit is obtained to the phase function of a SSObject . The phase curve is dependent on the solar elongation. This tool or functionality may be at Level 3, although the results of the phase function fitting could be brought into the SUI subsequently.
Basic Course:
The Science User fits a phase function to the brightness of a SSObject , with corresponding DIASources .
Alternate Course:
N/A.
2.1.26 Obtain photometry from the AstroObject Catalog
Description:
A Science User wishes to obtain photometry from the AstroObject Catalog for AstroObjects fitting a particular user-specified set of properties and/or positions on the sky.
Basic Course:
Invoke: Execute Box Search .
The Science User executes a rectangular box search centered on a particular sky position.
Invoke: Query AstroObject Catalog .
Alternate Courses:
Invoke: Execute Cone Search
Invoke: Extract Objects with User-Specified Properties
2.1.27 Perform Fitting of Object Color Distribution
Description: A histogram is created to show the distribution of Objects by color. An analytical function can be fit to the distribution of colors for SSObjects or AstroObjects .
Basic Course: The Science User performs statistical or functional fitting to determine the color distributions for SSObjects or AstroObjects .
Alternate Course: No SSObjects or AstroObjects are available on which to perform the fitting.
2.1.28 Select AstroObjects of Given Period
Description: As a query of the AstroObject Catalog , all AstroObjects with a given period are selected.
Basic Course: The Science User inputs a period of variability when performing a query of the AstroObject Catalog . The query returns with all AstroObjects having this period.
Alternate Course: The Science User can alternatively filter on the results of a more general query of the AstroObject Catalog all AstroObjects having a given period.
Also, the result of the query could be null, if no AstroObjects fit this criterion.
2.1.29 Separate Sample Into Photometric Redshift Bins
Description: The Science User separates a sample constructed from a query of the AstroObject Catalog into bins based on ranges in photometric redshift. It is assumed that photometric redshift is computed in the pipeline for AstroObjects flagged as galaxies.
Basic Course: AstroObjects are sorted into bins of a specified size, or range, of photometric redshift.
Alternate Course: No binning is performed.
2.1.30 Visualize Sample by Photometric Redshift
2.1.31 Visualize and Analyze Cleaned Color-Magnitude Diagram
Description:
Basic Course: The Science User renders a 2-D plot, within the User Workspace, of the cleaned color-magnitude diagram, with proper-motion AstroObjects removed.
The Science User may subsequently analyze these diagrams by, e.g., overlaying theoretical model isochrones on the diagrams (to determine ages of the stellar populations evident in the diagrams), etc.
Alternate Course: The Science Use r determines that the query result may not have been adequately cleaned and does not visualize and analyze the resulting color-magnitude diagram.
2.1.32 Will the AstroObject Catalog have a column flag for AstroObjects with proper motion?
2.2 Science User Interface
2.2.1 Basic Archive Access
02C.05.01 Basic Archive Access Tools
The distinction between "simple" and "complex" use cases is that a simple use case can be performed with a single query of the LSST catalogs. A complex use case requires processing LSST data to derive quantities that are not stored in the catalogs and/or require joining LSST data with data from other VO resources.
This WBS element includes software programs, configuration files, unit tests, component integration tests, and documentation that implement the Archive access capabilities.
Archive catalog data is selected based on user specifications of catalog properties.
Data Archive Access provides means to identify and access a variety of pre-defined, summary data queries across the entire archive of data.
NOTE: The UML for this WBS element is in development at this time.
Figure 5: Basic Archive Access
2.2.1.1 Execute Box Search
Description:
Basic Course:
Given input RA, DEC pairs, search for all AstroObjects in the AstroObject Catalog whose positions fall within the box centered on the RA, DEC pairs.
Alternate Course:
Science User invokes alternate search technique, e.g., Execute Cone Search .
2.2.1.2 Execute Cone Search
DESCRIPTION:
Execute Cone Search
TBD
2.2.1.3 Extract AstroObjects with User-Specified Properties
Description: This is a Basic Archive Access Tool to extract AstroObject s from the AstroObject Catalog with values or ranges of values of user-specified properties, based on parameters (columns) in the Catalog. These could include, e.g., magnitude, color, indication of variability, period, photometric redshift, etc.
Basic Course:
The Science User enters values or range of values for one or more Catalog parameters or columns. Color, for instance, will likely need to be specified as the difference of two magnitude columns.
Alternate Course:
The Science User invokes an alternate access or search technique.
2.2.1.4 Extract SSObjects with User-Specified Properties
Description: This is a Basic Archive Access Tool to extract SSObjects from the SSObject Catalog with values or ranges of values of user-specified properties, based on parameters (columns) in the Catalog. These could include, e.g., semi-major axis, inclination, eccentricity, etc.
Basic Course:
The Science User enters values or range of values for one or more Catalog parameters or columns. The Science User may need to first query the SSObject Reference Catalog .
Alternate Course:
The Science User invokes an alternate access or search technique.
2.2.1.5 Extract Time Sequence of Exposures
DESCRIPTION:
BASIC COURSE:
Science User enters the following in the Image Sequence User Input screen:
Sky Region
Observing Filter
a prefix to be used in naming the returned URL
a format for the image cited in the returned URL
System:
validates the specified sky region and filter
queries the image metadata catalogue using the parameters from the Image Sequence User Input screen.
retrieves the CCD Image list which overlays the user's specified parameters.
extracts the CCD Image Collection from the LSST Image Archive.
converts the extracted CCD Image Collection into the format specified, and renames the images
to include prefix, time, and filter
places the converted images into a parent directory.
displays an Image Sequence Success screen which shows:
a) A URI for the directory containing the converted images
b) The number of files in that directory
c) Disclaimer that sampling is irregular in space and time.
ALTERNATE COURSES:
sky region invalid
observing filter invalid
sky region completely outside LSST survey area
Image Sequence Failure screen returns sky region not in data message
system unavailable
Image Sequence Failure screen returns system unavailable message
2.2.1.6 Extract Time Series for Objects
DESCRIPTION: This is a Basic Archive Access Tool to extract time series for an AstroObject from the AstroObject Catalog .
BASIC COURSE:
User enters the following in the GUI screen "Get objects"
sky region boundaries OR LSST object identifier(s)
filter information
time interval
output format (file, diagram, etc)
quantities to return
System
gets time series from object catalog
returns quantities specified by user, in user-specified format
ALTERNATE COURSES:
System returns "System unavailable" screen, if unavailable
System returns "No object found" screen, when no object satisfies search criteria
2.2.1.7 Federate Query Results with External Catalogs
Description:
Federate Query Results with External Catalogs
Basic Course:
Science User queries AstroObject Catalog and specifies query results to be federated with an external catalog(s).
System: returns query result and performs federation of result with external catalog(s). VO protocols are employed to facilitate cross-matching.
Alternate Course:
Specified external catalog(s) has no cross-match with query result.
2.2.1.8 Query AstroObject Catalog
DESCRIPTION: This is a Basic Archive Access Tool to access AstroObject Catalog data.
Basic Course:
At the system level, the AstroObject Catalog is queried, based on various parameters specified by the Science User .
Alternate Course:
N/A.
2.2.1.9 Query Image Archive
DESCRIPTION: This is a Basic Archive Access Tool to access Image data.
Basic Course:
At the system level, the Image Archive is queried, based on various parameters specified by the Science User .
Alternate Course:
N/A.
2.2.2 Data Analysis and Visualization
WBS 02C.05.02 Data Analysis and Visualization Tools
This WBS element includes software programs, configuration files, unit tests, component integration tests, and documentation that implement the Data Analysis and Visualization capabilities. Data visualization capabilities include the ability to view large-scale, multi-dimensional data in a variety of plots and views.
Data Analysis permits querying, formatting, analyzing, and plotting data in a variety of 2D and 3D representations, with analytical overlays and statistical data.
Figure 6: Data Analysis and Visualization
2.2.2.1 Science User
2.2.2.2 Blink/Display Movie of Multiple Images
DESCRIPTION:
Blink/Display Movie of Multiple Images
BASIC COURSE:
This could also include displaying a time-series "movie" of Images .
ALTERNATE COURSE:
2.2.2.3 Calculate Commonly-used Statistics for Catalog Quantities
DESCRIPTION:
We do NOT mean two-point correlations.
BASIC COURSE:
ALTERNATE COURSE:
2.2.2.4 Create 2D Display of Catalog Query Result
DESCRIPTION: This is a Data Analysis and Visualization Tool to produce a two-dimensional representation of two columns in the result of a query of the AstroObject Catalog or SSObject Catalog .
BASIC COURSE: The Science User specifies which two columns from the query result to plot in this visualization tool. The Science User can interact with the plot and further refine its appearance within the tool.
ALTERNATE COURSE: N/A.
2.2.2.5 Create 3D/4D Display of Catalog Query Result
DESCRIPTION: This is a Data Analysis and Visualization Tool to produce a three- or four-dimensional representation of multiple columns in the result of a query of the AstroObject Catalog or SSObject Catalog .
BASIC COURSE: The Science User specifies which columns from the query result to plot in this visualization tool. The Science User can interact with the plot and further refine its appearance within the tool.
ALTERNATE COURSE: N/A.
2.2.2.6 Create Coadded Exposure
DESCRIPTION:
Given a set of Exposures, coadd and/or mosaic them.
BASIC COURSE:
ALTERNATE COURSE:
2.2.2.7 Display Exposure
DESCRIPTION:
Display an exposure.
BASIC COURSE:
ALTERNATE COURSE:
2.2.2.8 Display Light Curve for Object
DESCRIPTION: This is a Data Analysis and Visualization Tool to display the light curve for an AstroObject , after a time series has been extracted for it from the Source Catalog .
BASIC COURSE: The Science User invokes this display tool to view the light curve for an AstroObject . It is assumed that the indicator of variability for the AstroObject from the AstroObject Catalog is not null, however, this does not necessarily need to be the case. This tool can also be used for SSObjects .
ALTERNATE COURSE: No query has yet been performed of the AstroObject Catalog and therefore no light curve is available to visualize.
2.2.2.9 Display Tracks/Tracklets for Solar System Objects
DESCRIPTION:
This is a Data Analysis and Visualization Tool to overlay orbital tracks and tracklets for SSObjects on an Image .
BASIC COURSE: The Science User invokes the tracks/tracklets display tool to overlay the track/tracklet of a SSObject on an Image obtained through a query of the Image Archive.
ALTERNATE COURSE:
N/A.
2.2.2.10 Generate and Display Periodogram for AstroObjects
DESCRIPTION:
Although a period will be computed in the pipeline for all variable objects, a separate period-finding computational tool will allow the Science User to generate, using a selected algorithm, and view a periodogram for an AstroObject. This tool could be interactive with the light curve viewer tool.
BASIC COURSE:
ALTERNATE COURSE:
2.2.2.11 Overlay Catalog Query On Image
DESCRIPTION:
Overlay Catalog Query On Image
BASIC COURSE:
ALTERNATE COURSE:
2.2.2.12 Overlay Catalog Query on Image
Description: This is a data visualization tool to overlay the results of an AstroObject Catalog on an image, obtained as a separate query of the Image Archive.
Basic Course: The Science User overlays the results of the query of the AstroObject Catalog onto the Image of the field returned by the query of the Image Archive.
Alternate Course: The Image area does not contain the AstroObjects obtained from the AstroObject Catalog query.
2.2.2.13 Overlay Cleaned Catalog Query on Image
2.2.2.14 Retrieve Postage Stamp
DESCRIPTION: This is a Data Analysis and Visualization Tool to obtain a Postage Stamp cutout, i.e., a small, 30×30, sub-image at the position of a detected Source .
BASIC COURSE:
Obtain from the Image Archive, possibly as part of a Transient Alert retrieval, a postage stamp for a source.
ALTERNATE COURSE:
N/A.
2.2.2.15 Retrieve Survey Depth Map
DESCRIPTION:
Retrieve Survey Depth Map
BASIC COURSE:
ALTERNATE COURSE:
2.2.2.16 Subtract One Exposure from Another
DESCRIPTION:
Subtract One Image From Another
BASIC COURSE:
ALTERNATE COURSE:
2.2.3 Alert Subscription
WBS 02C.05.03 Alert Subscription Toolkit
This WBS element includes software programs, configuration files, unit tests, component integration tests, and documentation that implement the Alert Subscription capabilities.
Figure 7: Alert Subscription
2.2.3.1 Create Alert Category
DESCRIPTION: Create Alert Category -
BASIC COURSE:
The Alert Category Author defines an Alert Category in terms of data elements (astronomical characteristics, classification), availability (frequency, latency)
2.2.3.2 Create an Alert Filter
DESCRIPTION: This is a functionality within the Alert Subscription Toolkit.
BASIC COURSE:
The Public Interface User defines a "fine-grained" filter to determine how frequently or within what additional conditions the Alert should be delivered.
2.2.3.3 Deliver Alerts
DESCRIPTION: This is a function of the Alert Subscription Toolkit.
BASIC COURSE:
For all Alerts newly generated
The System examines an Alert and determines which Subscribers to deliver it to.
The System places the Alert into a queue for delivery
The System delivers the Alerts in the queue to their destination
NOTE: Is this done on a per Alert basis or on batches?
2.2.3.4 Record Alert
DESCRIPTION: Record Alert -
BASIC COURSE:
For each newly generated Alert
The System records the Alert in the Alert Archive
NOTE: How often, per Alert, per batch?
2.2.3.5 Retrieve Alerts
DESCRIPTION: Retrieve Alerts -
BASIC COURSE:
The Public Interface User queries the Alert Archive to retrieve current or past Alerts
2.2.3.6 Subscribe to Alert Category
DESCRIPTION: This is a functionality within the Alert Subscription Toolkit.
BASIC COURSE:
The Public Interface User accesses the available Alert Categories and selects an Alert Category
ALTERNATE COURSES:
1. The Public Interface User optionally defines a "fine-grained" filter to determine how frequently or within what additional conditions the Alert should be delivered.
2. Invoke "Create an Alert Filter"
2.2.4 User Assistance/Help Desk
WBS02C.05.04 User Assistance/Help Desk
This WBS element includes software programs, configuration files, unit tests, component integration tests, and documentation that implement the User Assistance capabilities.
Figure 8: User Assistance/Help Desk
2.2.4.1 Maintain Helpdesk with Query Tracking
2.2.5 User Workspace Management
WBS 02C.05.05 User Workspace Toolkit
This WBS element includes software programs, configuration files, unit tests, component integration tests, and documentation that implement the User Workspace capability.
Figure 9: User Workspace Management
2.2.5.1 Save Query Result to User Workspace
Description: As the result of a query of the AstroObject Catalog , the output of the query is saved to the User Workspace.
Basic Course:
The Science User saves the output from the AstroObject Catalog query to the User Workspace .
Alternate Courses:
The Science User decides not to save the query output to the User Workspace .
Additionally, the Science User may subsequently, e.g., analyze a color-color diagram rendered from the output resulting from the query of the AstroObject Catalog .
The Science User may subsequently, e.g., conduct a query of the Image Archive, to obtain an image of the field, and overlay the output from the AstroObject Catalog query onto the Image.
2.2.5.2 Save Subset of Query Result to User Workspace
Description: The result of Science User analysis on the output of a query of the AstroObject Catalog is saved to the User Workspace. Such analysis could consist of, e.g., further refinement of the selection of AstroObjects by color, magnitude, variability, star/galaxy separation, photometric redshift, etc.
Basic Course:
The Science User saves the output from analysis of the AstroObject Catalog query to the User Workspace .
Alternate Courses:
The Science User decides not to save the analysis output to the User Workspace .
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