ARCHES Integrated Cluster Finder tutorial

 Support: arches.support [at] astro.unistra.fr

Click  here to connect the service.

Step 1. Registration and Login

To use the ICF one has to register. The user defines a login name and a password on the registration page and clicks on the “register” button. A new account is created and one is are logged in immediately.

 

Step 2. Adding new fields

The ICF works on user-defined fields which are defined by a unique ID (user-defined) and equatorial coordinates. A circular area with a maximum of 8’ around the defined coordinates is inspected by the ICF. The UserID has to be an integer value.

To add a new field click on the “Add new field” item in the main menu. You will be redirected to the field creation page. Two ways are available:

1. Add a single field by providing it’s RA, DE (in decimal degrees) and UserID
2. Upload an ASCII file containing 3 columns: UserID, RA and DE.

If the “Run ICF on the new field” checkbox is activated, the server attempts to download data (on the server located at OAS Strasbourg) and run the cluster search on the new data (this might take time). The default catalog is used in this case, see below for its meaning.

Step 3. Managing fields and running the ICF

One can view and manage fields that were previously defined on the “List fields” page. There one finds some brief information on the defined fields:

• UserID - the unique ID that defined by the user
• ra, decl - field coordinates
• mocs - list of surveys used by the ICF that can provide data for this field (AllWISE is not listed, as it is an all-sky survey and coverage thus granted)
• catalogs - list of catalogs for which data was already downloaded by ICF with the number of galaxies for each catalog given in brackets
• Cluster detections - total number of ICF cluster detections for this field

Single click on the row in the table selects/deselects the row. Double-click leads to a page with detailed information on the field. The ‘Search’ button provides a simple way to filter data.

The Drop-down box ‘Active catalog’ provides the list of catalogs that can potentially be used by the ICF. The user selects which catalog to be used for the next run of the ICF.

 

Clicking on the “Run ICF” button will start the ICF run on selected field with selected catalog. The data for this fields/catalog combination will be downloaded to the dedicated ARCHES server at OAS and cluster finding will be started.

Selected fields can also be deleted by clicking on the “Delete” button. WARNING! A field deletion cannot be undone.

Step 4. Viewing and downloading results

There are several ways to analyse results of the ICF runs:

1. Using the “List fields” page, described above. One can get a summary on the defined fields and the detections counts (in the last column of the table)
2. Using individual field information page, that can be accessed by double-clicking on a selected row in the table on the ‘List fields’ page. The new page provides:

1. Link to NED search for the location of the field (within 2’). Results are shown in the new browser tab.
2. Plot of the multiplicity function. The user can download data that was used to produce this plot by clicking on the “Export plot data” button below the plot. Exported data is one file or several files gzipped into one. Each file represents the results of an ICF run on a single catalog and contains 3 columns: redshift z, λ(z) value at this redshift and a number of galaxies with known spectroscopic redshift falling in this redshift bin
3. Catalog information. This table lists catalogs that were used for cluster finding for this field, number of galaxies in this catalog for this field, total number of detections made by ICF and dates of last data loading and ICF run.
4. Detections table. Lists all detections in all catalogs for this field. Clicking on “Show only good detections” will hide detections with confidence less than 85%

3. Using List detections page. This page provides a full list of detections for all fields defined by user. On this page one can:

1. Change row selection by single-clicking on the row or by using “(De)Select all” button.
2. Click on “Show only good detections”. That will leave only detections with confidence more than 85% visible.
3. Click “Export selected to VOTable” button. This will produce a VOTable that will contain the same information as listed in the table (only rows selected will be included).
4. Click on “Export possible members to VOTable”. This will produce a VOTable for each selected row (if there is more than one row selected then files will be gzipped into a single archive). Such table contains information on possible member galaxies - their position, membership probabilities and magnitudes from the catalog in which this detection was done.

 

Glossary:

• Field - user-defined circular area. Defined by the location of the center in equatorial coordinates and a unique user ID, which is an integer value.
• Survey - one of the large-scale photometric surveys used by the ICF.
• Catalog - synonym for Survey in most cases except the default catalog (xmatch) which is a combination of 3 surveys: SDSS, UKIDSS and AllWISE.
• Detection (or cluster detection) - peak in the λ(z) function reported by the ICF. A field can have multiple detections, in one or several catalogs.

 

 

List of surveys used:

Survey	Frequency bands	Covered area (deg2)	Number of objects
AllWISE	W1 (3.4 μm), W2 (4.6 μm)	41000	747,634,026
UKIDSS	JHK	4000	82,655,526
SDSS (DR9)	ugriz	14555	932,891,133
CFTHLS-Wide	photo-z	157	35,651,677
CFTHLS-Deep	photo-z	5.25	2,293,851
ALHAMBRA	photo-z	4	441,303