Information on Service 'The PPMXL Catalog'

[Use this service from your browser]

Further access options are discussed below

PPMXL is a catalog of positions, proper motions, 2MASS- and optical photometry of 900 million stars and galaxies, aiming to be complete down to about V=20 full-sky. It is the result of a re-reduction of USNO-B1 together with 2MASS to the ICRS as represented by PPMX. This service additionally provides improved proper motions computed according to 2016AJ....151...99V.

For a list of all services and tables belonging to this service's resource, see Information on resource 'The PPMXL Catalog'

Service Documentation

To query this data, you can use

You can retrieve also the whole data set as a gzipped text file from http://vo.ari.uni-heidelberg.de/ppmxl (43.5 GiB). The columns in the text file are in database order as documented in the table info in DB order with columns separated by vertical bars ("|").

If you run DaCHS yourself, you can use a C booster kindly provided by Hailong Zhang. Instructions on usage are at the head of the file.

David Tholen kindly provided code to convert this into a collection of files for easy consumption by FORTRAN programs.

In 2016, John Vickers provided a global correction of the PPMXL proper motions based on extragalactic objects (2016AJ....151...99V). The results are given in the vickers_pmra and vickers_pmde columns. The coefficients we used are available at pmr-coefficients.csv and pmd-coefficients.csv. When used with the Code we actually used to compute the corrected values (adding healpix interpolation to the upstream from https://github.com/johnjvickers/PPMXL_Correction), these files have to be renamed pmr.csv and pmd.csv, respectively.

Overview

You can access this service using:

This service is published as follows:

local means it is listed on our front page, ivo_managed means it has a record in the VO registry, gavo means it is within GAVO's service registry.

Other services provided on the underlying data include:

Input Fields

The following fields are available to provide input to the service (with some renderers, some of these fields may be unavailable):

NameTable Head DescriptionUnitUCD
DEC Delta (ICRS) Declination (ICRS decimal) deg pos.eq.dec
hscs_pos Position/Name Coordinates (as h m s, d m s or decimal degrees), or SIMBAD-resolvable object N/A N/A
hscs_sr Search radius Search radius in arcminutes N/A N/A
ipix Id Identifier (Q3C ipix of the USNO-B 1.0 object) N/A meta.id;meta.main
MAXREC Match limit Maximum number of records returned. Pass 0 to retrieve service parameters. N/A N/A
RA Alpha (ICRS) Right Ascension (ICRS decimal) deg pos.eq.ra
RESPONSEFORMAT Output Format File format requested for output. N/A meta.code.mime
SR Search Radius Search radius deg N/A
VERB Verbosity Exhaustiveness of column selection. VERB=1 only returns the most important columns, VERB=2 selects the columns deemed useful to the average user, VERB=3 returns a table with all available columns. N/A N/A

Default Output Fields

The following fields are contained in the output by default. More fields may be available for selection; these would be given below in the VOTable output fields.

NameTable Head DescriptionUnitUCD
_r Dist. Distance to cone center deg pos.distance
b1mag USNO mag (B1) B mag from USNO-B, first epoch Note 1 mag phot.mag;em.opt.B
b2mag USNO mag (B2) B mag from USNO-B, second epoch Note 1 mag phot.mag;em.opt.B
dej2000 Dec Declination J2000.0, epoch 2000.0 deg pos.eq.dec;meta.main
e_deepDE E_deepde Mean error in Dec at mean epoch deg stat.error;pos.eq.dec;meta.main
e_pmDE Err. PM(Dec) Mean error in pmDE deg/yr stat.error;pos.pm;pos.eq.dec
e_pmRA Err. PM(RA) Mean error in pmRA*cos(delta) deg/yr stat.error;pos.pm;pos.eq.ra
e_raepRA E_raepra Mean error in RA*cos(delta) at mean epoch deg stat.error;pos.eq.ra;meta.main
Hmag m_H H selected default magnitude from 2MASS mag phot.mag;em.IR.H
imag USNO mag (I) I mag from USNO-B Note 1 mag phot.mag;em.opt.I
ipix Id Identifier (Q3C ipix of the USNO-B 1.0 object) N/A meta.id;meta.main
Jmag m_J J selected default magnitude from 2MASS mag phot.mag;em.IR.J
Kmag m_K_s K_s selected default magnitude from 2MASS mag phot.mag;em.IR.K
pmDE PM(Dec) Proper Motion in Dec deg/yr pos.pm;pos.eq.dec
pmRA PM(RA) Proper Motion in RA*cos(delta) deg/yr pos.pm;pos.eq.ra
r1mag USNO mag (R1) R mag from USNO-B, first epoch Note 1 mag phot.mag;em.opt.R
r2mag USNO mag (R2) R mag from USNO-B, second epoch Note 1 mag phot.mag;em.opt.R
raj2000 RA Right Ascension J2000.0, epoch 2000.0 deg pos.eq.ra;meta.main

VOTable Output Fields

The following fields are available in VOTable output. The verbosity level is a number intended to represent the relative importance of the field on a scale of 1 to 30. The services take a VERB argument. A field is included in the output if their verbosity level is less or equal VERB*10.

NameTable Head DescriptionUnitUCD Verb. Level
raj2000 RA Right Ascension J2000.0, epoch 2000.0 deg pos.eq.ra;meta.main 1
dej2000 Dec Declination J2000.0, epoch 2000.0 deg pos.eq.dec;meta.main 1
pmRA PM(RA) Proper Motion in RA*cos(delta) deg/yr pos.pm;pos.eq.ra 1
pmDE PM(Dec) Proper Motion in Dec deg/yr pos.pm;pos.eq.dec 1
ipix Id Identifier (Q3C ipix of the USNO-B 1.0 object) N/A meta.id;meta.main 5
_r Dist. Distance to cone center deg pos.distance 10
vickers_pmra PM'(RA) Proper motion in RA as re-corrected according to 2016AJ....151...99V, cos(delta) applied. This is only available for objects with 2MASS J magnitudes. e_pmRA still is suitable as an error estimate. N/A pos.pm;pos.eq.ra 10
vickers_pmde PM'(Dec) Proper motion in Dec as re-corrected according to 2016AJ....151...99V. This is only available for objects with 2MASS J magnitudes. e_pmDE still is suitable as an error estimate. N/A pos.pm;pos.eq.dec 10
e_raepRA E_raepra Mean error in RA*cos(delta) at mean epoch deg stat.error;pos.eq.ra;meta.main 15
e_deepDE E_deepde Mean error in Dec at mean epoch deg stat.error;pos.eq.dec;meta.main 15
e_pmRA Err. PM(RA) Mean error in pmRA*cos(delta) deg/yr stat.error;pos.pm;pos.eq.ra 15
e_pmDE Err. PM(Dec) Mean error in pmDE deg/yr stat.error;pos.pm;pos.eq.dec 15
Jmag m_J J selected default magnitude from 2MASS mag phot.mag;em.IR.J 15
Hmag m_H H selected default magnitude from 2MASS mag phot.mag;em.IR.H 15
Kmag m_K_s K_s selected default magnitude from 2MASS mag phot.mag;em.IR.K 15
nobs #obs Number of observations used Note 4 N/A meta.number;obs 20
e_Jmag Err(m_J) J total magnitude uncertainty mag stat.error;phot.mag;em.IR.J 20
b1mag USNO mag (B1) B mag from USNO-B, first epoch Note 1 mag phot.mag;em.opt.B 25
b2mag USNO mag (B2) B mag from USNO-B, second epoch Note 1 mag phot.mag;em.opt.B 25
imag USNO mag (I) I mag from USNO-B Note 1 mag phot.mag;em.opt.I 25
r1mag USNO mag (R1) R mag from USNO-B, first epoch Note 1 mag phot.mag;em.opt.R 25
r2mag USNO mag (R2) R mag from USNO-B, second epoch Note 1 mag phot.mag;em.opt.R 25
epRA Epra Mean Epoch (RA) yr time.epoch;pos.eq.ra 25
epDE Epde Mean Epoch (Dec) yr time.epoch;pos.eq.dec 25
e_Hmag Err(m_H) H total magnitude uncertainty mag stat.error;phot.mag;em.IR.H 25
e_Kmag Err(m_K_s) K_s total magnitude uncertainty mag stat.error;phot.mag;em.IR.K 25
magSurveys USNO Mag src. Surveys the USNO-B magnitudes are taken from Note 2 N/A meta.code 28
flags Flags Flags Note 3 N/A meta.code 28

Copyright, License, Acknowledgements

To the extent possible under law, the publisher has waived all copyright and related or neighboring rights to PPMXL. For details, see the Creative Commons CC0 1.0 Public Domain dedication. Of course, you should still give proper credit when using this data as required by good scientific practice.

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VOResource XML (that's something exclusively for VO nerds)

Note 1

Magnitudes from USNO-B should be used with care. Photometric calibration may be severely off for some plates.

For objects from PPMX (bit 1 set in flags), these magnitudes have a special meaning as per the following table:

PPMXL column PPMX column PPMX content
b1mag Cmag Catalogue magnitude from source
b2mag Bmag Johnson B magnitude
r1mag Rmag calc. Ru magnitude from source
r2mag N/A always None
imag Vmag Johnson V magnitude

See also the PPMX table info .

Note 2

magSurveys is built by concatenating the digits assigned to the surveys for b1mag, b2mag, r1mag, r2mag, and imag (in this sequence). The digits are those of given in Note h to Table 3 in 2003AJ....125..984M, except we do not distinguish POSS-II N and SERC-I as a part of POSS-I-N (i.e., both 7 and 9 are 7 here).

From this field, you can also see which of the surveys contributing to USNO-B had positions for the object.

Note 3

The flags column contains a bitwise or of warnings and similar conditions. The bit's meaning is as follows:

bit 0:If set, one of the coordinates had an excessively large chisquare.
bit 1:Row is from PPMX. These objects are mostly Tycho stars that were masked out of USNO-B. For these, the USNO magnitudes (b1mag through imag) have special meanings. See the note on magnitudes.
bit 2:Row is from PPMX and replaces a single row from USNO-B. This is done when the astrometry from PPMX was better (in terms of error estimates) than the astrometry of the corresponding PPMXL object.
bit 3:Row replaces multiple USNO-B1.0 objects. When PPMX contains an object that has more than one counterpart in PPMX-L, all such counterparts are discarded on the assumption that they should have been matched in USNO-B1.0 or result from erroneous matches. For these rows, bit 1 is always 1.
Note 4

nobs may be NULL for stars coming from ARIHIP or Tycho-2 via PPMX (i.e., bit 1 is set in flags).