CHARM2
A Catalogue of High
Angular Resolution
Measurements
September 2004
Release
3.0
European Southern Observatory
CHARM2
A Catalogue of High
Angular Resolution
Measurements
September 2004
Release
3.0
European Southern Observatory
Changes record
|
Version |
Date |
Changes |
|
Evaluation |
|
All |
|
Release
1.0 |
|
Column
"Angular Distance" |
|
Release
2.0 |
|
Added
Functionalities, corrections. Change of title and references, to complement
the paper submitted to A&A |
|
2.1 |
|
Added
Kc, notes, est diam. |
|
2.2 |
|
Added
description of Geo |
|
2.3 |
|
Debugging,
public release |
|
3.0 |
|
Changes
for CHARM2 |
This document describes the contents of CHARM2
Catalogue (previously known as the ESO VLTI Main Catalogue) and the structure
of the related files. It is available in electronic format, and it has links or
references to the following documents:
|
This
document |
|
|
The
CHARM2 Table, full format |
|
|
List
of publications |
|
|
Archive
update instructions (internal use only) |
The CHARM2 Catalogue is an Excel spreadsheet with
links to the documents above, as well as to the actual Data Archive. The Data
Archive and some link functionalities might not be fully available for general
distribution.
The CHARM2 Catalogue CHARM2.xls
includes several worksheets. They are briefly described below, and a full
explanation is provided separately in the remainder of this document.
|
Main Catalogue Table |
|
|
Statistical summary, magnitude histograms, etc |
|
|
Directory root names (internal use only) |
|
|
Format for Catalog updates |
|
|
Format for TCS Catalog updates |
|
|
Geometry, baselines, visibility, plots |
|
|
Hidden sheets |
Used for internal computations |
N. Sequential
order in the table. This is a free index, which is updated when the table is
sorted or regenerated. See also: Ser.
Ser. Serial
order in the table. This is an index fixed at the time of release. See also: N.
Source Link to the directory which
contains the source data. The name is chosen arbitrarily, although care has
been taken to use the designation of the original paper from which the source
was extracted (lowercase, stripped of +/– and special symbols). Clicking on the
link will open the directory. See also: Cross-Identifications, Update.
V Flag: "Y" means
that the source has been observed by the VLTI and the data are public.
Type A short abbreviation to identify
the type of the source. The types introduced with the first release of the
catalogue are given in Table
1, but additional codes may be introduced since this is
an arbitrary field.
Table 1.
Codes for the source types.
|
Code |
Source measurement in the
corresponding reference |
|
|
Unresolved (upper limit
may be given) |
|
Diam |
Stellar diameter resolved |
|
Bin |
Binary or multiple star |
|
Com |
|
|
|
Calibrator |
Cross-Identifications A multi-column field (4 fields in the first
release, but the actual number in the next versions may change). The choice of
identifications is arbitrary, but as a rule of thumb 1-2 are from visual
catalogues (usually SAO and HD when available), and 1-2 are from IR surveys
(usually IRC and IRAS when available). In case of a bright or famous object, HR
numbers or Flamsteed names may be used.
Method A code to identify the
method of observation used for the determination reported in the table. The
codes are listed in Table
2.
Table 2.
Codes for the Observation Methods
|
Code |
Method of Observation |
Note |
|
LO |
Lunar Occultation |
|
|
LBI |
Long-Baseline
Interferometry |
|
|
SPE |
Speckle Interferometry
(all methods) |
Dismissed with CHARM2 |
|
Radio |
Radio Measurements (incl.
mm, sub-mm) |
Dismissed with CHARM2 |
|
EST |
Estimated diameter |
|
|
AM |
Aperture Masking |
Dismissed with CHARM2 |
|
FGS |
HST Fine Guidance Sensors |
Dismissed with CHARM2 |
|
|
Indirect Methods
(Spectrophotometry) |
|
Lambda Wavelength of
observation, if given in the paper. This is listed in different ways, depending
on the type of measurement:
-
one or two numbers, in which case it means l
(and Dl)
in mm;
-
a filter type. The usual standard photometric names apply (for
instance: V, K, N)
-
a symbol, for special or narrow filters. Examples can be: CVF (Circular
Variable Filter, i.e. a narrow bandwidth filter used in the near-IR), Ha,
Brg.
-
"mult" indicates that the observations has been carried out
at multiple wavelengths simultaneously.
UD Diameter Uniform disk angular diameter,
if available, as reported in the paper. This entry has 3 columns, where the
values are all expressed in milliarcseconds (mas). These are the angular
diameter, its error, and an upper limit estimate, respectively. The entries for
the angular diameter and the upper limit should be mutually exclusive, and the
error is not always given. See also LD
Diameter,
Visibility.
LD Diameter Limb-darkened angular diameter,
if available, as reported in the paper. This entry has two columns, which list
the angular diameter and its error in units of mas. See also: UD Diameter.
Shell Marks the presence
of a circumstellar shell, either as a flag "Y", or with a
characteristic size in mas.
Binary In case
the source is a binary or multiple star, the following entries are listed:
sep: separation in mas, as
reported in the reference. For LO measurements, this is often only the
projected separation along the occultation PA (see below). In case of
multiplicity (triple and higher), only one entry is reported, without a
specific rule. In general, the result listed is the one which constituted the
specific contribution of the corresponding reference. See also PA and Type.
PA: position angle in degrees.
This can be the true position angle, or the angle of the projection in case of
1-D measurements such as is in general the case for LO. In case of a multiple
star, only one entry is present and the same considerations apply as for sep.
R: brightness ratio
(brighter to fainter), at the observation wavelength as reported in lambda and/or in the corresponding
reference. In case of a multiple star, only one entry is present and the same
considerations apply as for sep.
Typ: The type of binary. At the
time of the initial release of the catalogue, the codes used are: D (double), T
(triple), Q (quadruple), M (multiple, i.e. triple or higher), ND (not detected,
in case of a source reported as binary or multiple in the literature). S
indicates a single star (the binary star is disclaimed, typically due to poor
observations), while B? indicated that the binary is doubtful. A missing Typ
entry implicitly indicates a double star. Some codes can be followed by a
question mark in case of doubt.
Computed Diameter Angular diameter and its
error, computed on the basis of a formula as described in Method. An error is included
whenever possible. The values entered in this column should be used with
caution. Completely erased with CHARM2.
Method A formula which combines
different entries in the catalogue, to yield a theoretical angular diameter and
possibly its associated error. See also: Computed Diameter.
The methods currently included are:
BV: Bartholdi (thesis, 1976) relationship based on (B-V) and V. Well-suited
for main sequence stars hotter than K.
VB: Van Belle (priv. comm. 2000) relationship based on (V-K) and
luminosity class. The apparent angular sizes versus V-K color are
estimated in the case of :
-
Main Sequence stars with a V-K
from –0.5 to 0.5
-
Giant and Super Giant with a V-K
from 2.0 to 8.0
-
Evolved Sources : Variable stars with V-K from 5.5 to 13.0
Well suited for cool main sequence stars, late-type giant stars, AGB
stars.
For what concern the errors, we have assumed a fixed error on B, V, K
photometry, which has been arbitrarily set to 0.1mag. This assumption is, in
many cases, not very realistic and the derived errors must be taken with
caution.
Note: Completely erased with CHARM2.
Comments Comments extracted from the reference or inserted
by the catalogue compiler.
Coordinates Source coordinates. The five columns list right
ascension, declination, proper motions and epoch, respectively. The format of
right ascension is hh.mmsss. The format of declination is (-)dd.mmssss. The
proper motions values are set to zero when not available. Proper motions are
expressed in "/year. See also the worksheet Coords for an alternate coordinate
format. See also: Ang.
Dist.
Quick Reference Data This field has several columns, whose number
and nature can vary in future releases as needed on the basis of practical
experience. At this time, they include the fields described in Table
3. Entries are compiled from different sources. In the
most common case, they are extracted from the Simbad database. They can also include data from the corresponding
reference, or from private unpublished data. See also Simbad, Phot, Spec, References.
Simbad This is a link to the
information on the specific source, as listed in the Simbad database. It can be
a local file on disk (code D), or a URL that allows to look up Simbad directly
(code U). Both codes can be present. A code N, or empty, means that no Simbad
entry is available for the source. The choice to have both stored information
and an active link allows for the maximum flexibility: D links are immediate,
and should have most of the information always available with a click. U links
provide always complete and updated information (expecially for what concerns
literature references), but require Internet connection and can be slow. See also: Chart, Update.
Phot Link
to a private compilation of photometric data on the source. The data may be
unpublished. See also Spec, Update. Note: removed with CHARM2.
Spec Same
as Phot, for spectroscopic data. Note: removed with CHARM2.
Chart Link
to a finding chart, if available. The chart is an image of Digital Sky Survey
(DSS) in JPG format, covering 10'x10'. DSS-1 is used, but extensions to DSS-2
can be foreseen and therefore a code D1 is used. Future extensions might add
the D2B and D2R codes (blue and red). See also: Simbad.
Table
3. Quick Reference Data Fields.
|
|
Field |
Data |
|
1 |
B |
Blue Magnitude |
|
2 |
|
Code for B – all
empty |
|
3 |
V |
Visual Magnitude |
|
4 |
|
Code for V – all
empty |
|
5 |
K |
K Magnitude |
|
6 |
|
Code for K |
|
7 |
Kc |
Correlated K
magnitude (incl. visibility^2) |
|
8 |
Spectrum |
Spectral Type |
|
9 |
12μm |
12μm Flux
(Jy) |
|
10 |
|
Code for
12μm Flux (m=MSX) |
|
11 |
Var. Type |
Variability type
(from Simbad) |
|
12 |
Parallax |
|
|
13 |
Rad. Vel. |
Radial velocty in
km/s |
References Publications
which include the source under consideration. This is usually a code with a
sequential number. For the sake of convenience, this is usually also a link to
the list of publications publicat.doc. In turn, this has a link
to the corresponding publication in electronic format (available only in the
full implementation of the archive).
Ang. Dist. Angular
distance (in degrees) computed from a reference point whose right ascension and
declination are set by the user in row 2 and 3, in this order, of the same
column. Note that no corrections are made for different epochs between the
reference point and the coordinates of each entry. Note: there are 9 hidden
columns in front of Ang.Dist. See also: coordinates.
Visibility Visibility
of the source, with the baseline (expressed in meters) and the wavelength
(expressed in microns) defined by the user at the top of the column. For each
entry, the four columns list an angular diameter (when applicable), its error,
the computed visibility and relative error. The angular diameter can be set by
the user: by default, it is taken from the
UD Diameter , LD
Diameter, Shell ,Upper limit, Computed Diameter columns, in this order when available. Only in the first two cases and
in the last one, can the error on the angular diameter be
provided in CHARM2. If present, then in addition to the visibility also the
relative error on the visibility is computed. Note that this is an approximated
error: it is computed as (vis(j+Dj)-vis(j))/vis(j). All visibilities are computed as sqrt((2J0(x)/x)2),
and errors are relative errors.
Stats This worksheet displays some summary statistics. Included are
histograms of:
-
Angular diameter
-
Total number and source types
-
Statistics on bibliographical references
AD Map This worksheet displays a plot of the source positions in the sky,
according to the coordinates computed in Coords (note: this worksheet must be filled). No correction for precession is
applied. The limits are set by the view available from VLTI at Paranal.
Update This worksheet is used to store the root names of the directories in
the Data Archive. It is intended for internal management only.
The columns in this
worksheet are:
Subdir Location: the directory which holds the source data (raw data files, results of
analysis, log files, etc)
Root: the name displayed in the Main File (see also Source). This is generally fixed
by the authors according to VLT-TRE-ESO-15000-2746.
Simbad Data: the file with the data retrieved from the
Simbad database (see also Simbad).
Own Photometry: File with photometric information (see also Phot).
Finding Chart: File with the finding chart (see also Chart).
Simbad Name: name used for Simbad queries.
Update: date of last update of source data.
A macro button (gen
structure) allows to fill the full worksheet, starting from the names
provided in column root. The user should take care of filling manually
the entries in Simbad Name and Update.
Coords This worksheet is used to store the source coordinates and other
information in a format specific for updates of the VLTI Standard Format
Catalog. It is intended for internal management only. Two macro buttons permit
to clear the worksheet (when not needed, in order to save space on the total
size of CHARM2.xls), and to regenerate
it automatically. For this, the last row of the worksheet must be identical
with the last row of the main Table.
TCS Catalog This worksheet is used to store the source coordinates and other
information in a format that can be converted into a TCS Catalog. It is
intended for internal management only. Two macro buttons permit to clear the
worksheet (when not needed, in order to save space on the total size of CHARM2.xls), and to regenerate it automatically. For this,
the last row of the worksheet must be identical with the last row of the main Table.
Geo This worksheet is used to perform computations regarding observational
parameters of the sources present in CHARM2. Dates and times can be set, as
well as coordinates of an observatory and of sources, to compute quantities
such as baselines projection and position angle, sidereal times, airmass,
visibility and related error, etc.
Plots can also be generated.