X-CLASS database user's guide

Permissions

Different level of access rights have been defined for the X-CLASS database application. These rights are attached to the various roles you can play when you get connected to the server. The acceptable roles are the following :

• visitor: It is a role granted to any registered user. A simple look at the public cluster sample is enabled.
• collaborator: This role is given to the active members of the X-CLASS collaboration. The complete set of data is accessible.
• referee: This role is granted to an anonymous person who has to evaluate proposals submitted by the X-CLASS team.
• administrator: This role pertains to the person in charge of the database management. It is used to register new users and update user profiles.

Session

Each time you enter the database service you are given a unique session. The session remains valid until you press the logout button or, if it is no longer used, after 60 minutes.

Quality

(not available in visitor and referee modes)

Rank assigned by the moderator after inspection of the X-ray/optical overlays. This number is intended to help in the ranking of cluster candidates.

• 1 - unlikely (default value prior to moderator evaluation)
• 2 - possible
• 3 - good candidate

Multiplicity

(not available in visitor and referee modes)

Definition of source multiplicity :

• primary source: (M=1) cluster source classified as primary in the case where this object is present on several pointings. Source providing the best X-ray information, thus not necessarily the one having the smallest R_offaxis (if the pointing in question is affected by flares for instance).
• secondary source: (M=2) cluster source(s) corresponding to a M=1 source on adjacent pointing(s). There are at most two M=2 cluster sources linked to a M=1 source.
• secondary maximum: (M=3) secondary maximum (QSO or substucture) presents in a M=1 or M=2.
• supplementary exposure: (M=4) sources detected on pointings deeper than the nominal survey exposure time.
• previous value: (M=5) counterparts in previous catalogue release.

Cluster subset

You can select a subset of clusters by defining a list of minimum and maximum values between which cluster attributes must be. The list of criteria are organized in 4 groups.

• Area: the right ascension and the declination of the selected clusters should be in the range defined in the fields.
• Quality: the quality given to the selected clusters should be in the chosen range. In addition the instrument used to observe the clusters should be the defined one.
• X-ray properties (pipeline outputs): the attributes of the selected clusters should be in the range defined in the fields. This group of fields is dedicated to the values associated with the sum of the 3 (MOS1+MOS2+PN) detectors.
• Selection: perform an action on the whole 3 groups of criteria, displays the chosen subset of clusters.

The groups of criteria are presented on separated panels. In each panel four buttons are displayed :

• clear: allows you to erase the content of the fields.
• get: computes the current mininum and maximum values in the list of good clusters.
• load: fetches from the database your personal values saved in a previous operation.
• save: save into the database your current values.

By pressing the select button you extract a subset of clusters from the list of good clusters according to the following rules :

• an empty field is ignored : the associated test is not evaluated.
• in a same group tests are combined with the and logical operation. For example by specifying four angles in the Area panel you will get only clusters located in the selected rectangle of the sky.
• the groups Area and Quality are combined with and.
• the groups defining the detector values can be simply ignored by choosing the option na (not applicable) or they can be combined with the and or or logical operation.

Sky coordinates

A Right Ascension (R.A.) can be given in hours with value in the range 0, 24 or in degrees between 0 and 360. The value can be formatted:

• as a decimal number of degrees , e.g. 1.2450
• as a string h min s e.g. 1 h 15 min 23.4 s. The symbols h, min, s are mandatory and must be separated by space from the digits, the number of seconds can be a floating point number.
• as a string hh:mm:ss e.g. 01:15:23.4. The three tokens must be present.
• as a string hh mm ss e.g. 01 15 23.4. The three tokens must be present.

A Declination is displayed in degrees and must be given in degrees in the range -90, +90. This value can be formatted

• as a decimal number, e.g. -2.2451
• as a string d° m' s'' e.g. -12° 15' 23.4''. The symbols °,','' are mandatory and must be stuck to the digits. The symbol for seconds is two apostrophes '' not one double quote ".
• as a string dd:mm:ss e.g. -12:15:23.4. The three tokens must be present.
• as a string dd mm ss e.g. -12 15 23.4. The three tokens must be present.

Naming conventions

xclass***** is the standard name of X-CLASS catalogue objects (e.g.: xclass00020, xclass02328, etc.).
To avoid any confusion, please use this labelling for your publications.

Description of the table Subset of Clusters

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tag(*) - Cluster tag

xclass - Cluster name

short name(*) - Pipeline (XAmin3.5) name

            Ex: 0560191901_87_v3.5_c1_20ks

            0560191901 - XMM observation
            87 - pipeline detection number
            v3.5 - pipeline version
            c1 - cluster classification
            20ks - exposure time

R.A. pipeline - Right Ascension as calculated by the pipeline (XAmin3.5)

R.A. measured(**) - Right Ascension, measurement by hand in the course of profile fitting

DEC pipeline - Declination as calculated by the pipeline (XAmin3.5)

DEC measured(**) - Declination, measurement by hand in the course of profile fitting

NED - Number of NED sources within 3 arcmin. Only the identifications with redshift are listed.

quality(*) - Rank assigned by the moderator after inspection of the X-ray/optical overlays. This number is intended to help in the ranking of cluster candidates. (for details see section Quality)

class(*) - Preliminary redshift range assigned by the moderator

obs - XMM parent observation

main(*) - Primary source in the case of redundant source (for details see section Multiplicity)

nb links(*) - Number of links associated to main source

redshift - Redshift value if available

status - Redshift status

            inexistent - no cluster conspicuous in the spectroscopic redshift space

            pending - awaiting the results of the spectroscopic runs

            photometric - if photometric

            tentative - if less than three concordant redshifts within 3 arcmin are available

            provisional - the available information is not allowing us to verify the existence of a galaxy cluster in this position

            confirmed - cluster definitively confirmed

total rate - Total (MOS1+MOS2+PN) count-rate in the 0.5-2keV band (raw pipeline output)

profile - Results from the manual count-rate measurements

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(*) (for internal use) not available in visitor and referee modes
(**) in the case of very bright nearby clusters or cluster strongly affected by point-like sources or by the CCD gap, the position of the X-ray centroid determined by pipeline can be off by a few tens of arcseconds. The exact position is a posteriori corrected in the course of the manual fitting.

© X-CLASS Collaboration

xclassdb version : 11.0 since : 12 February 2021.