The 2MASS Redshift Survey

Huchra et al., ApJS, in press

http://tdc-www.harvard.edu/2mrs/
catalog version 2.4, 2011 Dec 16
maintained by Lucas Macri, lmacri@tamu.edu 
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*                                                                             *
* Any use of the redshift data provided in this catalog is subject to the     *
* following terms:                                                            *
*                                                                             *
* (1) All entries with a bibliographic code that starts with "20112MRS" must  *
*     be cited as "Huchra, et al., The 2MASS Redshift Survey, ApJS, in press" *
*                                                                             *
* (2) All other entries must be cited using their respective bibliographic    *
*     codes, provided in the column 28 of the catalog.                        *
*                                                                             *
* (3) Please do not redistribute any of these files. This will help us ensure *
*     that all users receive the most up-to-date version. Please redirect any *
*     requests you receive for this catalog to lmacri@tamu.edu or to          *
*     http://tdc-www.harvard.edu/2mrs/                                        *
*                                                                             *
* (4) Please notify lmacri@tamu.edu of any errors you find, so we may correct *
*     them in the next version of the catalog. Thanks!                        *
*                                                                             *
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A. 2MASS Redshift Survey input catalog:

The initial selection of sources for this redshift survey was based on the 2MASS Extended Source Catalog (XSC), provided by Tom Jarrett. We also included sources listed in 2MASS Large Galaxy Atlas (LGA), version 2.5, by Jarrett et al. (2003AJ....125..525J).

The 2MASS photometric pipeline performed a variety of magnitude measurements for each band. We selected the isophotal magnitudes, measured at the K=20 mag/sq arcsec isophote, as our primary set of magnitudes. We also include the "total magnitudes" derived by the pipeline, but do not use them for our sample selection. The columns extracted from the 2MASS XSC photometry table are listed below. Please refer to the following links for details of the 2MASS XSC and LGA photometry:

http://irsa.ipac.caltech.edu/applications/2MASS/PubGalPS/XSC_key.html
http://irsa.ipac.caltech.edu/applications/2MASS/LGA/

We applied an extinction correction using the maps of Schlegel, Finkbeiner & Davis (1998ApJ...500..525S). Our tables report the extinction-corrected 2MASS magnitudes, and we also provide the value of E(B-V) from SFD98 which we used for the corrections.

We selected 45,086 sources which met the following criteria:
  1. Ks <=11.75 mag and detected at H-band
  2. E(B-V) < 1.0 mag
  3. |b| > 5.0 deg for 30 < l < 330 ; |b| > 8.0 deg otherwise
We rejected 324 sources deemed to be of galactic origin (multiple stars, planetary nebulae, HII regions), image artifacts, and pieces of galaxies detected as separate sources by the 2MASS pipeline. These objects are listed in the file "2mrs_1175_rej.dat", located in the "add_rej" subdirectory.

Additionally, we flagged 314 bona fide galaxies with compromised photometry for reprocessing. Some have bright stars very near the nucleus which were not detected by the pipeline. Some are in regions of high stellar density and their center positions and/or isophotal radii have been incorrectly measured by the pipeline. Some are very close galaxy pairs or multiples.

72 of the flagged galaxies have been kindly reprocessed by Tom Jarrett at the time of submission for publication. The original XSC entries are listed in the file "2mrs_1175_rep.dat", while the updated entries are listed in the file "2mrs_1175_add.dat". Note that the latter file has 74 entries because two close galaxy pairs have been split into individual galaxies.

87 of the flagged galaxies are not severely affected by the nearby stars, although they could benefit from reprocessing at a later date. They have been left in the catalog with their original magnitudes for now, and are listed in the file "2mrs_1175_flg.dat"

165 of the flagged galaxies are severely affected by the nearby stars, but have not been reprocessed yet. They have been removed from the catalog and are listed in the file "2mrs_1175_flr.dat"

Our final input catalog (after the additions and deletions listed above) contained 44,599 entries. In this work, we present redshifts for 43,533 of these, or 97.6% of the sample.

B. 2MASS Redshift Survey catalog contents:

The main redshift catalog is in the "catalog/" subdirectory. Additional redshifts for fainter galaxies can be found in the "extra/" subdirectory.

This distribution contains both space-delimited ASCII and FITS binary table versions of the catalog, with extensions ".dat" and ".fits" respectively.

2MASS galaxies that meet the selection criteria listed above and have a measured redshifts are listed in the files called "2mrs_1175_done.[dat,fits]" (43,533 entries)

2MASS galaxies that meet the selection criteria listed above but do not have a measured redshift are listed in the files called "2mrs_1175_nocz.[dat,fits]" (1,066 entries). If you have observed one of these galaxies please let us know!

Below is a description of the columns in the catalog. Columns 1-3, 6-17, and 19-22 contain information obtained from the 2MASS XSC photometry tables. The original names of these columns in the XSC database are given in brackets. The remaining columns contain information added by us as part of this work.
  1. ID : 2MASS ID [XSC: designation]
  2. RAdeg : RA (J2000.0) in decimal degrees [XSC: sup_ra]
  3. DECdeg: DEC (J2000.0) in decimal degrees [XSC: sup_dec]
  4. l : Galactic longitude [calculated by us]
  5. b : Galactic latitude [calculated by us]
  6. k_c : Ks isophotal magnitude, extinction corrected [XSC: k_m_k20fe]
  7. h_c : same for H [XSC: h_m_k20fe]
  8. j_c : same for J [XSC: j_m_k20fe]
  9. k_tc : "Total" magnitude, extinction corrected [XSC: k_m_ext]
  10. h_tc : same for H [XSC: h_m_ext]
  11. j_tc : same for J [XSC: j_m_ext]
  12. e_k : Uncertainty in k_c [XSC: k_msig_k20fe]
  13. e_h : same for h_c [XSC: h_msig_k20fe]
  14. e_j : same for j_c [XSC: j_msig_k20fe]
  15. e_kt : same for k_tc [XSC: k_msig_ext]
  16. e_ht : same for h_tc [XSC: h_msig_ext]
  17. e_jt : same for j_tc [XSC: j_msig_ext]
  18. e_bv : E(B-V) from Schlegel, Finkbeiner & Davis (1998ApJ...500..525S)
  19. r_iso : log10 of K=20 mag/sq arcsec isophotal radius (in arcsec) [XSC: r_k20fe]
  20. r_ext : same for "total magnitude" extrapolation radius [XSC: r_ext]
  21. b/a : axial ratio from co-added JHKs images [XSC: sup_ba]
  22. flgs : photometry confusion flags from 2MASS XSC database [XSC: cc_flg, k_flg_k20fe, h_flg_k20fe, j_flg_k20fe]. A "Z" in the first column indicates that we have used magnitudes from the 2MASS LGA.
  23. type : galaxy type, following ZCAT convention (see below)
  24. ts : source of type (JH=John Huchra; ZC=ZCAT; ND=NED; NN=not available)
  25. v : redshift
  26. e_v : uncertainty in redshift, when available
  27. c : code for input catalog containing redshift (see below for details)
  28. v_src : bibliographic code for source of redshift (follows NED convention)
  29. CAT_ID: name of galaxy in input redshift catalog

C. Sources of redshifts

All 2MASS XSC entries meeting the selection criteria listed in (A) were used as an input list to query the following databases:
Queries against earlier versions of these databases were conducted throughout the duration of this survey, starting in early 1998. Galaxies without a match in any database at the time of the query were targeted for observation at the Fred L. Whipple Observatory 1.5-m telescope, the Cerro Tololo Interamerican Observatory 1.5-m telescope, and the McDonald 2.1-m telescope. Observations were conducted between 1998 July and 2011 January.

The provenance of redshifts used in this catalog is detailed below. In the case of multiple redshifts for a given galaxy, we gave preference to our own observations (codes C/D/F below) over any previously published value. However, we list the alternative redshifts in the sub-directory "cat_diff" for the benefit of users who wish to give preference to other catalogs or who wish to combine the measurements into a mean value.
The one-character codes listed below are used in column 27 of the catalog (see above). The values in brackets indicate the number of redshifts associated with each source.

D. Details of adopted redshifts that are not the NED default value

The files included in the subdirectory "cat_diff" contain lists of the 2MASS XSC entries for which we did not use the default redshift provided by SDSS DR8, 6dF DR3, or NED at the time of our queries. The contents of these files are as follows:

E. 2MRS "bibcodes"

As stated in the terms of use at the top of this file, any redshift with a bibliographic code starting with "20112MRS" should be cited as "Huchra, et al., The 2MASS Redshift Survey, in preparation". There are several variants of this code in the data files, primarily meant for internal use by 2MRS project members. Here we provide additional information on these codes for those readers who might be interested.

F. Galaxy types

Galaxy types are provided for a virtually complete sub-sample of 20,860 objects with K<=11.254 mag and |b|>10 deg. 5,729 galaxies in this sub-sample had never been classified and thus were visually inspected and typed by John Huchra. These galaxies are identified with "JH" in the "type source" column (column 24). Galaxy types for the remainder of the sub-sample, and for an additional 5,064 fainter objects were already stored in ZCAT and have been propagated into the 2MRS catalog. These are identified with "ZC" in the "type source" column.

Galaxy types are encoded in column 23 following the ZCAT convention. The first two characters are numeric and correspond to the following:
The next three characters are alphabetical and correspond to the following:
Objects removed from the original XSC catalog (2mrs_1175_rej.dat) are typed as follows:

G. Additional redshifts for 2MASS galaxies outside the survey limits

Redshifts for an additional 196,963 2MASS galaxies beyond the main catalog limits are tabulated in files located in the "extra" subdirectory. This catalog is provided in both ASCII and FITS binary table format in the files called "2mrs_extra_done.[dat,fits]". The format of this catalog is similar to the main catalog, but contains an additional 3 columns with the following information:
  1. RAdlt: delta-RA (in arcseconds) between the 2MASS galaxy position and the reported position of its matched counterpart in a redshift catalog
  2. DCdlt: delta-Dec (in arcseconds), same as column #30
  3. tl: matching tolerance for the catalog containing this redshift
The provenance of redshifts used in this catalog is detailed below. In the case of multiple redshifts for a given galaxy, we gave preference to our own observations (codes C/D/F below) over any previously published value. However, we list the alternative redshifts in the sub-directory "cat_diff" for the benefit of users who wish to give preference to other catalogs or who wish to combine the measurements into a mean value. PLEASE NOTE: 25,552 entries in this "extra" catalog have an "O" in column 27, indicating that the redshift information was obtained by matching the 2MASS XSC against ZCAT. These redshifts were not verified against NED. Some redshifts from older publications listed in ZCAT are known to have typos in their coordinates and/or redshifts, resulting in bogus matches. Users are encouraged to double-check the validity of these redshifts against NED and report any discrepancies to lmacri@tamu.edu

Additionally, very few of these galaxies were visually inspected to ensure their photometry was not compromised by stars, image defects or pipeline errors (see discussion on rejected sources in [A] above). This could be particularly important for objects at low galactic latitude. A few sources that were rejected are listed in "2mrs_extra_rej.dat", some that were flagged are listed in "2mrs_extra_rej.dat" and a small number that were reprocessed by Tom Jarrett can be found in "2mrs_extra_add.dat".

The files included in the subdirectory "cat_diff" contain lists of the 2MASS XSC entries for which we did not use the default redshift provided by SDSS DR8, 6dF DR3, or NED at the time of our queries. The contents of these files are as follows:
Additional 2MRS "bibcodes" for galaxies in the "extra" sample:

H. Redshifts for additional galaxies not listed in the 2MASS XSC

As part of our observations, we obtained redshifts for 14 galaxies located in close proximity to 2MASS sources but not actually listed in the XSC. Those redshifts are presented in the file "2mrs_nocat_done.dat" in the "extra/" subdirectory. We generated pseudo-2MASS IDs for these objects based on their coordinates. Since these galaxies are not listed in the XSC, we are unable to report any magnitude measurements for them.