J/MNRAS/482/5167 The 2M-ZoA galaxy catalogue (Schroder+, 2019)
A zone of avoidance catalogue of 2MASS bright galaxies.
I. Sample description and analysis.
Schroder A.C., Van Driel W., Kraan-korteweg R.C.
<Mon. Not. R. Astron. Soc., 482, 5167-5189 (2019)>
=2019MNRAS.482.5167S 2019MNRAS.482.5167S (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Galaxies, IR ; Photometry, infrared
Keywords: astronomical data bases: catalogues - galaxies: general -
galaxies: photometry - infrared: galaxies
Abstract:
We present a homogeneous 2MASS bright galaxy catalogue at low Galactic
latitudes (|b|≤10.0°, called Zone of Avoidance) which is complete
to a Galactic extinction-corrected magnitude of KSo≤11.25m. It also
includes galaxies in regions of high foreground extinctions
(E(B-V)>0.95mag) situated at higher latitudes. This catalogue forms
the basis of studies of large-scale structures, flow fields and
extinction across the ZoA and complements the ongoing 2MASS Redshift
and Tully-Fisher surveys. It comprises 3763 galaxies, 70% of which
have at least one radial velocity measurement in the literature. The
catalogue is complete up to star density levels of logN*/deg2<4.5
and at least for A(K)<0.6mag and likely as high as A(K)=20mag. Thus
the ZoA in terms of bright NIR galaxies covers only 2.5-4% of the
whole sky. We use a diameter-dependent extinction correction to
compare our sample with an unobscured, high-latitude sample. While the
correction to the Ks -band magnitude is sufficient, the corrected
diameters are too small by about 4" on average. The omission of
applying such a diameter-dependent extinction correction may lead to a
biased flow field even at intermediate extinction values as found in
the 2MRS survey. A slight dependence of galaxy colour with stellar
density indicates that unsubtracted foreground stars make galaxies
appear bluer. Furthermore, far-infrared sources in the DIRBE/IRAS
extinction maps that were not removed at low latitudes affect the
foreground extinction corrections of three galaxies and may weakly
affect a further estimated ∼20% of our galaxies.
Description:
In this first of a series of papers, we presented a magnitude-limited
catalogue of 2MASX galaxies at low Galactic latitudes and at high
foreground extinction levels. The catalogue supplements the
high-latitude 2MRS (Huchra et al., 2012, Cat. J/ApJS/199/26) and 2MTF
(e.g. Masters et al., 2014, Cat. J/MNRAS/443/1044) surveys with the
aim to obtain a homogeneous, complete, and truly 'whole-sky' survey
for cosmic flow analyses.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3a.dat 197 6913 2MASX ZOA sample
table3b.dat 197 502 2MASX EBV sample
tablea1a.dat 197 276 2MASX ZOA supplementary sample
tablea1b.dat 197 14 2MASX EBV supplementary sample
tablea2a.dat 197 31 2MASX ZOA exclusion sample
tablea2b.dat 197 1 2MASX EBV exclusion sample
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See also:
J/ApJS/199/26 : The 2MASS Redshift Survey (2MRS) (Huchra+, 2012)
J/MNRAS/443/1044 : GBT HI observations of 1194 spirals (Masters+, 2014)
Byte-by-byte Description of file: table*.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2MASX The 2MASX J identifier
(HHMMSSss-DDMMSSs J2000 format)
19- 25 F7.3 deg GLON Galactic longitude
28- 34 F7.3 deg GLAT Galactic latitude
36- 42 F7.3 mag E(B-V) The (B-V) color excess As derived from the
IRAS/DIRBE maps (Schlegel et al.,
1998ApJ...500..525S 1998ApJ...500..525S)
45 I1 --- class [1/9] Object flag (1)
48 A1 --- off [o-e] Object offset flag (2)
51- 52 A2 --- flg [ps? -] Object class (3)
55 A1 --- gal S[g/p] ample flag galaxy (4)
58 A1 --- TF [t-] Sample flag TF (5)
61 A1 --- obs [NP±] Sample flag HI observation (6)
64 A1 --- extd [*-] Sample flag extended sample (7)
67- 68 A2 --- DiscType [D1234o -n] Galaxy disc type (8)
71- 72 A2 --- 2MRS 2MRS flags (9)
75- 76 A2 --- vo Optical velocity measurement flag from the
literature (10)
79- 80 A2 --- vh HI velocity measurement flag from the
literature (11)
83 A1 --- NIR [UV-] Deep NIR image flag (12)
86- 87 A2 --- phot [apfco- ] Photometry flag (13)
90- 91 A2 --- ExtFlag Extinction flag (14)
94- 99 F6.3 mag K20 2MASX isophotal magnitude (15)
102-106 F5.2 mag H-K ? 2MASX isophotal colour H-K (15)
109-112 F4.2 mag J-K ? 2MASX isophotal colour J-K (15)
115-116 I2 --- vc 2MASX flag: the visual verification score of
a source (see Sect. 5.1)
119-123 F5.1 arcsec a 2MASX major diameter (twice the 2MASX
isophotal elliptical aperture semi-major
axis) (15)
126-129 F4.2 --- b/a ? 2MASX axis ratio of the J+H+Ks co-added
image at the 3-sigma isophote (16)
132-135 F4.2 --- st.dens ? 2MASX stellar density (co-added logarithm of
the number of stars (K<14mag) per sq.degree
around the object
138-144 F7.3 mag Ko ? Extinction-corrected K20 magnitude (17)
147-152 F6.2 mag H-Ko ? Extinction-corrected colour H-K (17)
155-160 F6.2 mag J-Ko ? Extinction-corrected colour J-K (17)
163-167 F5.2 mag AK Extinction in the K-band (b6) and applying a
correction factor of 0.86 (18)
170-174 F5.1 arcsec ad ? Extinction-corrected major diameter (19)
177-181 F5.2 mag Kod ? Extinction-corrected 2MASX isophotal
magnitude (19)
184-189 F6.2 mag H-Kod ? Extinction-corrected 2MASX isophotal
colour J-K (19)
192-197 F6.2 mag J-Kod ? Extinction-corrected 2MASX isophotal
colour J-K (19)
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Note (1): Object flag as follows:
1 = obvious galaxy
2 = galaxy
3 = probable galaxy
4 = possible galaxy
5 = unknown
6 = lower likelihood for galaxy
7 = unlikely galaxy
8 = no galaxy
9 = obviously not a galaxy
Note (2): Object offset flag as follows:
o = coordinates that are offset from the centre of the object
e = detections near the edge of an image (at an offset position from the
object centre) which were detected with properly centred coordinates on
the adjacent image
Note (3): Object class as follows:
p = PN
p? = possible PN
s = probable DIRBE/IRAS point source that was not removed from the
extinction maps (only the case if |b|<5°) and the extinction is
likely to be overestimated
s? = a possible DIRBE/IRAS point source
Note (4): Sample flag galaxy as follows:
g = galaxy (object classes 1-4)
p = galaxy candidates (class 5)
Note (5): Sample flag TF as follows:
t = the galaxy is inclined enough to be nominally included in the sample
for application of the Tully-Fisher relation.
We selected only 'sufficiently' inclined galaxies for this sample,
that is, galaxies with minor/major axial ratios (2MASX parameter) of
b/a≤0.5; at relatively high extinction values,i.e., AK≥0.50, we also
selected galaxies with a generous 0.5<b/a≤0.7 to account for the fact
that obscured galaxies appear rounder (Said et al., 2015MNRAS.447.1618S 2015MNRAS.447.1618S).
Note (6): Sample flag HI observation as follows:
N = the object was observed by us in the 21cm HI line with the NRT
(Kraan-Korteweg et al., 2018MNRAS.481.1262K 2018MNRAS.481.1262K)
P = the object was observed by us with the Parkes radio telescope (in prep)
+ = the object still needs to be observed for a redshift
Note (7): Sample flag extended sample as follows:
* = Objects that will not be included in the extended sample based on the
diameter-extinction correction (Kod≤11.25)
Note (8): Galaxy disc type as follows:
D1 = obviously visible disc and/or spiral arms
D2 = noticeable disc
D3 = possible disc
D4 = no disc noticeable
o = not possible to tell (likely due to adjacent or superimposed stars or
very high extinction)
Note (9): 2MRS flags as follows:
c = entry in the main catalogue,
e = entry in the extra catalogue (that is, outside the 2MRS selection
criteria)
cf = entry in the flg catalogue (affected by nearby stars, but not severely)
cp = entry in the flr catalogue (severely affected by nearby stars)
ca = objects that have been reprocessed and are both in the rep as well as add
catalogues (in the latter case with new IDs and photometry, not listed
by us)
ea = objects that have been reprocessed and are both in the rep as well as add
catalogues (in the latter case with new IDs and photometry, not listed
by us)
cr = objects rejected as galaxies and which can be found in the rej catalogues
er = objects rejected as galaxies and which can be found in the rej catalogues
cn = objects that have no redshifts yet and are listed in the nocz catalogues
en = objects that have no redshifts yet and are listed in the nocz catalogues
For a detailed description of the 2MRS sub-catalogues
see http://tdc-www.harvard.edu/2mrs/2mrs_readme.html
Note (10): Optical velocity measurement flag from the literature as follows:
o = optical measurement,
o? = questionable optical measurement or object ID,
g = the velocity shows it to be a Galactic object,
* = a yet unpublished measurement. Recently determined redshifts that are as
yet unpublished are (a) 2MRS optical data (Macri, priv.comm.),
(b) HIZOA Galactic Bulge survey Parkes detections (Kraan-Korteweg et al.
in prep), (c) ALFAZOA survey Arecibo detections (see McIntyre et al.
2015AJ....150...28M 2015AJ....150...28M for first results), (d) EBHIS-ZoA survey
Effelsberg detections (Schroder et al. 2019, ...), (e) the NRT
detections from Kraan-Korteweg et al. 2018MNRAS.481.1262K 2018MNRAS.481.1262K,
and (f) our Parkes (PKS) detections (Said et al. in prep.).
Note (11): HI velocity measurement flag from the literature as follows:
h = published HI velocity
h: = uncertain HI velocity
h? = uncertain object ID (based on a radio telescope"s large beam size that
may include nearby galaxies)
* = a yet unpublished measurement Recently determined redshifts that are as
yet unpublished are (a) 2MRS optical data (Macri, priv.comm.),
(b) HIZOA Galactic Bulge survey Parkes detections (Kraan-Korteweg et al.
in prep), (c) ALFAZOA survey Arecibo detections (see McIntyre et al.
2015AJ....150...28M 2015AJ....150...28M for first results), (d) EBHIS-ZoA survey
Effelsberg detections (Schroder et al. 2019, ...), (e) the NRT
detections from Kraan-Korteweg et al. 2018MNRAS.481.1262K 2018MNRAS.481.1262K,
and (f) our Parkes (PKS) detections
(Said et al. in prep.).
Note (12): Deep NIR image flag as follows:
U = a UKIDSS image exists
V = a VISTA image exists
Note (13): the 2MRS flags for questionable photometry (see 2MRS) are repeated
here as follows:
a = improved photometry exists
p = photometry is severely compromised
f = poor photometry; in addition
c = improved photometry exists in John Huchra"s original list (We give the
improved-photometry flag from John Huchra's original list (priv. comm.),
for 22 objects (8 of which are galaxies))
o = offset (see off)
Note (14): Extinction flag as follows:
e = likely wrong extinction value, either due to small-scale variations or a
non-removed IRAS/DIRBE point source
e? = a possible wrong extinction value.
Around some objects the foreground extinction shows a strong, local spatial
variation which is not reflected in the DIRBE/IRAS maps given their
relatively coarse pixel size of 6arcmin. Wherever the 10arcmin B- or R-band
images showed such obvious small-scale variations, we set an extinction flag.
Sometimes a variation across the image was discernible but without the
sharp edges typical of a dark cloud; in these cases we set a flag indicating
that the extinction could be wrong.
Note (15): Measured at the K=20mag/sq.arcsec isophote
Note (16): Single-precision entries are given in cases where the 2MASX
parameter sup_ba is not determined; these values were estimated from
the axial ratios available in the different passbands,
Note (17): Extinction in the JHK bands were converted from E(B-V) using RB=4.14
and the conversion factors AJ=0.21AB, AH=0.13AB and AK=0.09AB.
Note (18): The extinction correction factor 0.86 is described by Schlafly et
al., 2011ApJ...737..103S 2011ApJ...737..103S.
Note (19): An additional diameter-dependent extinction correction has been
applied (Riad et al., 2010, 2010MNRAS.401..924R 2010MNRAS.401..924R); only given for
objects flagged as galaxies (gal).
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Acknowledgements:
Anja Schroder, anja(at)hartrao.ac.za
(End) Patricia Vannier [CDS] 29-Aug-2019