MACHO Project: Variable Star Catalog Query Help

Index

1.0 Variable Star Catalog
2.0 Search Query Generation
3.0 Query Fields
3.1 Classification
3.2 Variability Index
3.3 Location
3.4 Units
3.5 Equinox
3.6 RA
3.7 Dec
3.8 Search Radius(arcmin)
3.9 Field.Tile.Seqn
3.9.1 Field.Tile.Seqn_list
3.9.2 Field.Tile.Seqn_parts
3.9.2.1 Field
3.9.2.2 Tile
3.9.2.3 Seqn
3.10 Average Magnitude
3.11 Average Amplitude
3.12 Amplitude (r = b) Accuracy
3.13 Average Period
3.14 Period (r = b) Accuracy
3.15 Statistics
3.15.1 Chi2r
3.15.2 Sig
3.15.3 Sup RSA
4.0 Navigation
4.1 Records per Page
4.2 Review and Edit Search Query
4.3 Query Form Reset
4.4 Query Form Submission

1.0 Variable Star Catalog

The Variable Star Catalog interface returns summaries of variable stars which satisfy user-defined criteria. The summaries provide hot-click access to a web lightcurve browser and hot-click selection for later ftp download of variable star lightcurve datasets.

2.0 Search Query Generation

The database search returns all records which satisfy the logical expression built from the user's input. The generated search query is composed of the form's fields separated by AND. Each field may be a composite of subfields. In that case, the generated field is composed of the subfields separated by OR. If no value is entered for a field and no default provided, it is not included. An example of the generated search query is: StarId_input AND AverageMagnitude_input AND Statistics_input .

The syntax of the field is defined by the record data. Refer to the descriptions below to determine if a field

  • allows a subfield list; or
  • is alphanumeric or numeric. On the input form, a list is represented by subfields separated by a comma (',').

    Numeric subfields may be either

  • an unadorned value,
  • a value preceded by an arithmetic symbol ('=', '<', '<=', '>', '>=', '<>'),
  • a value followed by an arithmetic symbol ('=', '<', '<=', '>', '>=', '<>'), or
  • two values separated by the range indicator (':').

    For example, a Variability_Index subfield defined thusly:
    "2.0, >50.0, 10.0:20.0, 1.0>"
    results in the logical sub-expression:
    "((Variability_Index_x100=200) OR (Variability_Index_x100>5000) OR (Variability_Index_x100=1000:2000) OR (Variability_Index_x100<100))" .

  • Note that the field's name was changed with the addition of a multiplier label. Additionally, the input values were multiplied by that value in order to convert the number to an integer.
  • Refer here for detailed information on the generated expressions.

    3.0 Query Fields

    The form's search fields are:

    3.1 Classification

    Variable star classification

  • Choose none if search should not be restricted by classification type. This is the default.
  • Choose select subset to restrict the search to a selected subset of star types.
  • The classifications are:
    RRL AB : RRLyrae ab
    RRL C : RRLyrae c
    RRL E : RRLyrae e
    Ceph Fundamental : Cepheid fundamental
    Ceph 1st Overtone : Cepheid first overtone
    LPV WoodA : LPV Wood-A
    LPV WoodB : LPV Wood-B
    LPV WoodC : LPV Wood-C
    LPV WoodD : LPV Wood-D
    EB : Eclipsing Binary (all kinds including Wood-E) -- default
    RRL + GB : RR Lyrae and GB blends (supersedes Cepheid first overtone in overlap region)
  • Example of subset selection:
    [x] RRL ab [ ] RRL c [x] RRL e [ ] Ceph Fund [ ] Ceph 1st Over
    [x] LPV WA [x] LPV WB [x] LPV WC [ ] LPV Wd [ ] EB [ ] RRL+GB

    3.2 Variability Index

    Variability index from Pierce et al, 1994, Nature 371:385.

  • Format is numeric. Arithmetic constructs, lists and ranges may be used.
  • Example: 24.11, >40.6, 3.5:5.60

    3.3 Location

    Area of the sky where stars to be selected are located.

  • Choose none if search should not be restricted by star location. This is the default.
  • Choose by RA and Dec if the search should be restricted to a portion of the sky.
  • Choose by Field.Tile.Seqn_list if the search should be restricted to explicitly listed Stars. This option does not allow any wildcards or range specifications.
  • Choose by Field.Tile.Seqn_parts if the search should be restricted to a group of Stars which will be defined using range notation and wildcard expansion.

    3.4 Units

    Units in which the RA, Dec and Search Radius will be entered.

  • Choose HMS/DMS/arcmin to select hours:minutes:seconds as units for RA, degrees:minutes:seconds for Dec, and arcminutes for the bounding box radius.
  • Choose radians to select radians as units for RA, Dec, and radius.
  • Choose degrees to select degrees as units for RA, Dec, and radius.

    3.5 Equinox

    Select the equinox in which the RA/Dec are expressed.

  • Options are: J2000, B1950

    3.6 RA

    Right Ascension of the center point in bounding box defined by the RA/Dec/radius parameters. Format varies according to the units selected.

  • For HMS/DMS/arcseconds, it is upto 8 characters: HH:MM:SS . Subfields may not be empty.
  • For radians, it is a positive decimal number.
  • For degrees, it is a positive decimal number.
  • Example: 5:1:15.2 (HMS)
  • Example: 1.31447 (radians)
  • Example: 75.313 (degrees)

    3.7 Dec

    Declination of the center point in bounding box defined by the RA/Dec/radius parameters. Format varies according to the units selected.

  • For HMS/DMS/arcseconds, it is upto 9 characters: [-]DD:MM:SS . Subfields may not be empty.
  • For radians, it is a decimal number.
  • For degrees, it is a decimal number.
  • Example: 69:25:59.5 (DMS)
  • Example: -69:25:59.5 (DMS)
  • Example: -1.21183 (radians)
  • Example: -69.433 (degrees)

    3.8 Search Radius

    Radius of the bounding box defined by the RA/Dec/radius parameters.

  • Format is numeric. Maximum is 300 arcseconds or the equivalent in the units chosen.
  • Example: 10 (arcseconds)
  • Example: .0003 (radians)
  • Example: .0167 (degrees)

    3.9 Field.Tile.Seqn

    The Field.Tile.Seqn number (also known as F.T.S) uniquely identifies a star within the context of the Macho Project databases. It is composed of atomic identifiers describing

  • the Field whose observations captured the star's data;
  • the Tile in which the star was found; and
  • finally, the sequence number of the star within the set of stars found in that Tile.

    Each atomic identifier is an integer number.

    3.9.1 Field.Tile.Seqn_list

    The syntax for F.T.S stars within the F.T.S input list is: field . tile . sequence .

  • Multiple stars should be separated by commas.
  • Each star must be explicitly and fully stated. Wildcards and range specifications are not allowed.
  • Example: 2.4662.12, 1.3441.15, 1.3441.25

    3.9.2 Field.Tile.Seqn_parts

    The components comprising the F.T.S parts input are defined below.

    3.9.2.1 Field

    Macho Project Field identifier for the region of the sky containing the desired star. A Field's region may overlap other Fields' regions. Refer here for the Macho Field definitions.

  • Format is numeric. Arithmetic constructs, lists and ranges may be used within a field. Constructs within a field will be ORed together; the three fields (Field, Tile, Seqn) will be ANDed together. A blank entry indicates no restriction by Field.
  • Example: 10, 15:45, >300

    3.9.2.2 Tile

    Macho Project Tile identifier for the region of the sky containing the desired star. Tiles are non-overlapping and are uniquely numbered over the entire sky in constrast to Fields which are composed of multiple Tiles and may overlap other Fields' regions.

  • Format is numeric. Arithmetic constructs, lists and ranges may be used within a field. Constructs within a field will be ORed together; the three fields (Field, Tile, Seqn) will be ANDed together. An empty entry indicates no restriction by Tile.
  • Example: 3000:4000 , 5678

    3.9.2.3 Sequence

    Macho Project identifier for a specific star within a Tile. The number was assigned during the creation of a Field's master SodoPhot template. The same template was used during photometry reduction of all of a Field's observations.

  • Format is numeric. Arithmetic constructs, lists and ranges may be used within a field. Constructs within a field will be ORed together; the three fields (Field, Tile, Seqn) will be ANDed together. An empty entry indicates no restriction by Sequence.
  • Example: 2543, <100

    3.10 Average Magnitude

    Magnitude averaged over all observations excepting those with values of -99, or magnitudes brighter than -12, or type outside of 1-6 or 21-26.

  • Choose none if search should not be restricted by star magnitude. This is the default.
  • Choose in Macho Instrumental rb if magnitude(s) will be entered as MACHO Instrumental red-blue values.
  • Choose in Kron-Cousins VR if magnitude(s) will be entered as Kron-Cousins VR transformations of the Macho instrumental values.
  • Values are numeric. Arithmetic constructs, lists and ranges may be used within a field. Constructs within a field will be ORed together; the three fields (V, R, V-R or r, b, b-r) will be ANDed together.
  • All three fields need not be entered. It was envisioned that the user would select the pair of fields most simply characterizing the information wanted.
  • Example: r [100:110 , >300] b [100:110 , >300] b-r [] r [100:110 , >300] b [] b-r [10:20] r [] b [100:110 , >300] b-r [10:20]

    3.11 Average Amplitude

    Amplitude Ave is the peak-to-peak amplitude of the best fit to the light curve.

  • Choose none if search should not be restricted by star amplitude. This is the default.
  • Choose in Macho Instrumental rb if amplitude(s) will be entered as MACHO Instrumental red-blue values.
  • Values are numeric. Arithmetic constructs, lists and ranges may be used within a field. Constructs within a field will be ORed together; the three fields (r, b, b-r) will be ANDed together.
  • All three fields need not be entered. It was envisioned that the user would select the pair of fields most simply characterizing the information wanted.
  • Example:
    V [10:11 , >14] R [10:11 , >14] V-R [] V [10:11 , >14] R [] V-R [1:5] V [] R [10:11 , >14] V-R [1:5]

    3.12 Amplitude (r=b) Accuracy

    Select stars whose r and b amplitude are equal within the specified percentage.

  • Example: to select stars whose r and b amplitudes are within 10% of each other, use: <10
  • Example: to select stars whose r and b amplitudes are exactly 10% of each other, use: 10

    3.13 Average Period

    Average Period is selected as the best 1 cycle period that matches the alternate focal plane's period. A value of -999 within the database indicates data was taken on only the alternate focal plane.

  • Choose none if search should not be restricted by average period . This is the default.
  • Choose in Days if average period will be a selection criteria.
  • Format is numeric. Arithmetic constructs, lists and ranges may be used within a field. Constructs within a field will be ORed together.
  • Units are Days.
  • Example: 88.2244

    3.14 Period (r=b) Accuracy

    Select stars whose r and b periods are equal to within the specified percentage.

  • Example: to select stars whose r and b periods are within 25% of each other, use: <25
  • Example: to select stars whose r and b periods are exactly 25% of each other, use: 25

    3.15 Statistics

  • Choose none if search should not be restricted by statistical attributes. This is the default.
  • Choose use chi2r sig supRSA if selection criteria will include statistical attributes.

    3.15.1 Chi2r

    Chi2r is a robust, weighted mean-square difference of the data and the fit. Only the central 80% of the differences are used in forming chi2r.

  • Format is numeric. Arithmetic constructs, lists and ranges may be used within a field. Constructs within a field will be ORed together.
  • Example:

    3.15.2 Sig

    Sig is the standard deviation of the focal plane's magnitude. A value of -99 indicates invalid data.

  • Format is numeric. Arithmetic constructs, lists and ranges may be used within a field. Constructs within a field will be ORed together.
  • Example:

    3.15.3 Sup RSA

    Sup RSA is the weighted mean absolute deviation of the data from the fit to the light curve. The weighting is such that good fits typically have values less than 1.0 A value of -999 indicates invalid data.

  • Format is numeric. Arithmetic constructs, lists and ranges may be used within a field. Constructs within a field will be ORed together.
  • Example: <=1.11 >3.75

    4.0 Navigation

    4.1 Records per Page

    Number of records processed per web page display. This number is also the upper bound on the number of lightcurve files fetched per ftp request. The maximum number is 1000. Default is 20. Although a limited number of records will be available per page, the full set of records satisfying the query are available via the next and previous buttons on the web page display.

  • Example: 15

    4.2 Review and Edit Search Query

    The user is given the option to review and edit the search query automatically generated from the form's input.

  • Choose no to skip the review and immediately initiate the database query. This is the default.
  • Choose yes to review the query before database submission. Detailed information on the database query syntax is provided in the editing link provided on the review page's display.

    4.3 Query Form Reset

    Select the Reset button to return the form to default values.

    4.4 Query Form Submission

    Select the Submit button to initiate input field validation and the subsequent creation of the database search expression.

    Acknowledgement to use when referencing MACHO Project data

    "This paper utilizes public domain data originally obtained by the MACHO Project, whose work was performed under the joint auspices of the U.S. Department of Energy, National Nuclear Security Administration by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48, the National Science Foundation through the Center for Particle Astrophysics of the University of California under cooperative agreement AST-8809616, and the Mount Stromlo and Siding Spring Observatory, part of the Australian National University."

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