J/ApJ/449/527 Galaxies in the zone of avoidance (Lu+ 1995)
Large-scale structures in the zone of avoidance: the galactic anticenter region
Lu N.Y., Freudling W.
<Astrophys. J. 449, 527 (1995)>
=1995ApJ...449..527L 1995ApJ...449..527L
ADC_Keywords: Galaxies, IR ; Infrared sources ; H I data
Keywords: galaxies: clustering - galaxies: distances and redshifts -
radio lines: galaxies
Abstract:
We have selected a sample of 876 galaxy candidates from the IRAS Point
Source Catalog in the region of 2h<RA<10h and 0deg<DE<36deg, which
crosses the Galactic anticenter part of the Zone of Avoidance (ZOA)
and includes most of the highly obscured Orion-Taurus complex region.
We have identified galaxies among the candidate sources by attempting
to detect the 21cm H I line of those sources which were not known to
be galaxies at the beginning of the survey. In this manner, we
constructed a galaxy sample which is largely free from Galactic
reddening. Of the 272 observed candidates, 89 were detected in the H I
line up to a heliocentric velocity of vh∼16,000km/s. The resulting
galaxy sample of 717 galaxies is fairly complete (within about 10%)
and uniform (within about 4%) in the part of the survey area 10deg
away from the Galactic plane and for velocities up to at least
9000km/s. This provides, for the first time, a largely unbiased view
on the large-scale structures in much of the survey area. Our main
results are the following:
(1) Several large voids are identified. In particular, a void between
RA∼3h and 4h, up to vh∼6000km/s, separates the Pisces-Perseus
supercluster at RA<3h from structures at RA>4h; and a "nearby void"
occupies most of our survey area and reaches out to a redshift of
nearly 3000km/s.
(2) We found no nearby galaxy concentration that could significantly
contribute to the "Local Velocity Anomaly" (LVA), but a general
excess of galaxies around vh∼5000km/s in the survey area.
(3) The contrast between the "Great Wall" at vh∼8500km/s and the
void in front of it appears to gradually diffuse out after it enters
the Zone of Avoidance from the northern Galactic hemisphere.
(4) Our data combined with other galaxy surveys in or near the
Galactic anticenter part of the ZOA suggest that the main ridge of the
Pisces-Perseus supercluster does also not extend to Abell 569, a
cluster in the northern Galactic hemisphere, and that the simple
gravitational model consisting of the Local Void of Tully & Fisher,
our nearby void, and Puppis and Fornax-Eridanus clusters would predict
a LVA whose direction is probably too far away from that derived from
observations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 30 899 List of the candidate sources
table3.dat 55 89 HI 21cm data of the detected galaxies
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See also:
II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- IRAS IRAS-PSC (Cat. II/125) name
11 A1 --- m_IRAS [AB] Multiplicity index on IRAS
12 A1 --- n_IRAS [*] Note on IRAS (1)
13- 15 I3 deg GLAT Galactic latitude
17 I1 --- n1 [1/3] Object category (2)
19 I1 --- n2 [0/2] HI velocity in range [0/8000] (3)
21 I1 --- n3 [0/1] HI velocity in range [8000/16000] (4)
23- 27 I5 km/s HV ? Heliocentric velocity
29- 30 I2 --- Ref [1/11]? References (5)
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Note (1): An * indicates PSC sources which fail to pass our selection criteria.
Note (2): Categories numbered as follows:
1 = Catalogued galaxies, i.e., sources flagged in the PSC to be
associated with one or more optical galaxy catalogs
2 = Galactic sources (as marked in the PSC)
3 = pure IRAS source
Note (3): A nonzero number indicates that the source was observed in one
of the two similar 21cm HI surveys over a velocity coverage of
(0-8000)km/s, where 1=the current survey and 2=Lu et al.
(1990ApJ...357..388L 1990ApJ...357..388L)
Note (4): An index of unity means that the source was observed in the
current survey over a velocity coverage of (8000-16000)km/s
Note (5): Reference that gives either the original redshift or identification,
or the original work of the redshift or identification, as follows:
1 = this paper
2 = Lu et al. (1990ApJ...357..388L 1990ApJ...357..388L)
3 = Pantoja et al. (1994AJ....108..921P 1994AJ....108..921P)
4 = Giovanelli & Haynes (1993, Cat. J/AJ/105/1271)
5 = the Third References Catalogue of Galaxies, de Vaucouleurs et al.,
1991, Cat. VII/155
6 = the NASA/IPAC Extragalactic Database (Helou et al., 1991, in
"Database and On-Line Data in Astronomy", ed. M.A. Albrecht &
D. Egret (Dordrecht: Kluwer), 89)
7 = Strauss et al. (1992, Cat. II/174)
8 = IRAS-1,2Jy redshift catalog (Strauss 1994 (Priv. Comm.), see also
Fisher et al. 1992ApJ...389..188F 1992ApJ...389..188F)
9 = the 1-in-6 redshift catalog of the Queen Mary-West Field College,
Durham, Oxford, and Toronto (Lawrence et al. 1994, preprint)
10 = Takata et al. (1994, Cat. J/A+AS/104/529)
11 = the catalog of IRAS point source redshift survey (Saunders 1994
(Priv. Comm.), see also Rowan-Robinson et al. (1991MNRAS.253..485R 1991MNRAS.253..485R)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS IRAS name (note that 04425+1058 is not in table2)
11 A1 --- m_IRAS [AB] Multiplicity index on IRAS
13- 17 I5 km/s HV50 Mean heliocentric velocity, taken to be the
middle point between the velocities at the
flux level 50% of the peak(s) on either
side of the profile
19 A1 --- l_Wm20 Limit flag on Wm20
20- 22 I3 km/s Wm20 Velocity width at 20% of the mean
flux density within the profile
24 A1 --- l_Wm50 Limit flag on Wm50
25- 27 I3 km/s Wm50 Velocity width at 50% of the mean
flux density within the profile
30- 32 I3 km/s Wp20 ? Velocity width at 20% of the peak(s)
35- 37 I3 km/s Wp50 ? Velocity width at 50% of the peak(s)
40- 42 I3 km/s Wp80 ? Velocity width at 80% of the peak(s)
44- 48 F5.2 Jy.km/s SHI Integrated HI flux
50- 54 F5.2 --- S/N Observed ratio of peak signal-to-noise
55 I1 --- Notes ? Notes about the HI observation (1)
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Note (1): Notes as follows:
1 = Widths are ambiguous
2 = The galaxy was detected in the OFF spectrum taken at the same
declination as the ON position but at an R.A. that is 117.0' east
of the ON position
3 = The peak widths are probably incorrect
4 = Possibly two galaxies along the line of sight
5 = The high-velocity wing of the profile is slightly beyond our
limiting velocity
6 = The galaxy was detected in the OFF spectrum taken at the same
declination as the ON position, but at an R.A. that is 91.8' east
of the ON position
7 = The galaxy was detected in the OFF spectrum taken at the same
declination as the ON position, but at an R.A. that is 109.5' east
of the ON position
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History:
* 01-Apr-1997: Prepared via OCR at CDS.
* 09-Jan-2013: standardized documentation and fixed 3 names in table3
in error from OCR process: 02249+2710 (02249+2740),
02569+1020 (02569+1022), 03459+1255 (03459+1259).
* 14-Jan-2013: further OCR errors detected by H. Andernach [Guanajuato
Univ.] in tables 2 and 3 (sign of GLAT in table2, missing notes
in table3)
(End) James Marcout, Patricia Bauer [CDS] 01-Apr-1997