J/MNRAS/433/543 Choirs, HI galaxy groups (Sweet+, 2013)
Choirs, HI galaxy groups: catalogue and detection of star-forming dwarf group
members.
Sweet S.M., Meurer G., Drinkwater M.J., Kilborn V., Denes H., Bekki K.,
Hanish D., Ferguson H., Knezek P., Bland-Hawthorn J., Dopita M.,
Doyle-Pegg M.T., Elson E., Freeman K., Heckman T., Kennicutt R., Kim J.H.,
Koribalski B., Meyer M., Putman M., Ryan-Weber E., Smith C.,
Staveley-Smith L., Wong O.I., Webster R., Werk J., Zwaan M.
<Mon. Not. R. Astron. Soc., 433, 543-559 (2013)>
=2013MNRAS.433..543S 2013MNRAS.433..543S
ADC_Keywords: Clusters, galaxy ; Galaxies, optical ; H I data
Keywords: galaxies: groups: general - galaxies: dwarf - Local Group -
radio continuum: galaxies
Abstract:
Hα observations centred on galaxies selected from the Hi Parkes
All-Sky Survey (HiPASS) typically show one and sometimes two
star-forming galaxies within the ∼15arcmin beam of the Parkes 64m
HI detections. In our Survey for Ionization in Neutral Gas Galaxies
(SINGG) we found 15 cases of HiPASS sources containing four or more
emission line galaxies (ELGs). We name these fields Choir groups. In
the most extreme case, we found a field with at least nine ELGs. In
this paper, we present a catalogue of Choir group members in the
context of the wider SINGG sample.
The dwarf galaxies in the Choir groups would not be individually
detectable in HiPASS at the observed distances if they were isolated,
but are detected in SINGG narrow-band imaging due to their membership
of groups with sufficiently large total HI mass. The ELGs in these
groups are similar to the wider SINGG sample in terms of size,
Hα equivalent width and surface brightness.
Eight of these groups have two large spiral galaxies with several
dwarf galaxies and may be thought of as morphological analogues of the
Local Group. However, on average our groups are not significantly Hi
deficient, suggesting that they are at an early stage of assembly, and
more like the M81 group. The Choir groups are very compact at
typically only 190kpc in projected distance between the two brightest
members. They are very similar to SINGG fields in terms of star
formation efficiency (SFE; the ratio of star formation rate to HI
mass), showing an increasing trend in SFE with stellar mass.
Description:
Our sample is drawn from the 292 HiPASS targets observed for SINGG.
HI measurements are all from the HiPASS HI catalogue HICAT (Meyer et
al. 2004MNRAS.350.1195M 2004MNRAS.350.1195M, Cat. VIII/73), except for two groups (HiPASS
J0443-05 and J1059-09). After noticing an anomalous HI mass for one
group, we manually remeasured the HI mass of every Choir group.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 102 15 Summary of Choir groups
table2.dat 134 89 Choir member descriptions
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See also:
VIII/73 : HI Parkes All Sky Survey Catalogue (HIPASS) (Meyer+, 2004)
J/ApJS/165/307 : SINGG. I. (Meurer+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- HIPASS Name assigned to field in HiPASS (JHHMM-DDa)
11- 22 A12 --- OName Optical name assigned to group as found in
NASA/IPAC Extragalactic Database
(NED; http://ned.ipac.caltech.edu/)
24- 25 I2 h RAh Field brightest source right ascension (J2000)
27- 28 I2 min RAm Field brightest source right ascension (J2000)
30- 34 F5.2 s RAs Field brightest source right ascension (J2000)
36 A1 --- DE- Field brightest source declination sign (J2000)
37- 38 I2 deg DEd Field brightest source declination (J2000)
40- 41 I2 arcmin DEm Field brightest source declination (J2000)
43- 47 F5.2 arcsec DEs Field brightest source declination (J2000)
49- 51 I3 Mpc Dist Distance based on the multipole attractor model
as in Mould et al. (2000ApJ...529..786M 2000ApJ...529..786M)
and adopting H0=70km/s/Mpc
53- 55 I3 kpc FOV [100/660] Field of view of ∼15arcmin at
the distance of the group
57- 58 I2 --- ELGs [4/10] Number of Emission-Line Galaxies
60- 64 F5.1 kpc Comp [27/420] Projected group compactness, estimated
by projected separation of two largest group
members (see Section 3.5)
66- 70 F5.2 [Msun] logMHI Logarithm of group HI mass from HiPASS
71 A1 --- n_logMHI [a] Remeasured logMHI (1)
73- 77 F5.2 --- HIdef HI deficiency parameter (2)
78 A1 --- n_HIdef [b] Group excluded (1)
80- 84 I5 km/s VHI Heliocentric HI velocity
86- 88 I3 km/s WHI Observed HI emission width.
89- 90 A2 --- --- [.0 ]
92- 95 I4 km/s W50l Narrow-band filter lower velocity range
96 A1 --- --- [-]
97-101 I5 km/s W50u Narrow-band filter upper velocity range
102 A1 --- n_W50u [c] Possible additional ELGs (1)
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Note (1): Notes as follows:
a = We remeasured HI mass for two groups whose HiPASS measurements were
incorrect. See Section 2 for more details.
b = We exclude these two groups from our HI deficiency analysis due to
field-of-view restrictions.
c = We note that the narrow-band filters used for these two fields overlap
but do not completely cover the extent of the observed HI emission
width. Therefore, there may be additional ELGs associated with these
groups which would be classified as Choir member galaxies but are not
detected in our imaging.
Note (2): HI deficiency parameter defined as the logarithmic difference
between the observed group HI mass and predicted group HI mass
(determined by summing the predicted HI masses of the individual group
galaxies). See Section 3.7 for calculation and discussion.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- SINGG Name assigned in SINGG (HiPASS name with
:Sn appended for nth source (JHHMM-DDa:Sn)
13 A1 --- n_SINGG [ab*] Note on SINGG galaxy (1)
16- 30 A15 --- OName Optical previously assigned ID based on
position match with NED
(http://ned.ipac.caltech.edu/)
32- 33 I2 h RAh Right ascension (J2000)
35- 36 I2 min RAm Right ascension (J2000)
38- 42 F5.2 s RAs Right ascension (J2000)
44 A1 --- DE- Declination sign (J2000)
45- 46 I2 deg DEd Declination (J2000)
48- 49 I2 arcmin DEm Declination (J2000)
51- 55 F5.2 arcsec DEs Declination (J2000)
57- 61 F5.2 arcsec re R-band effective radius
63- 66 F4.2 arcsec e_re rms uncertainty on re
68- 71 F4.2 --- a/b ?=- Ratio of major and minor axes
73- 78 F6.2 mag RMAG R-band absolute magnitude (AB mag)
80- 83 F4.2 mag e_RMAG rms uncertainty on RMAG
85- 90 F6.2 [mW/m2] logFHa Logarithm of total Hα flux, corrected
for Galactic extinction and [NII]
contamination
92- 95 F4.2 [mW/m2] e_logFHa rms uncertainty on logFHa
97-101 F5.2 mag/arcsec2 SuBre R-band effective surface brightness,
face-on and extinction-corrected
(Galactic and internal) (AB mag)
103-106 F4.2 mag/arcsec2 e_SuBre rms uncertainty on SuBre
108-130 A23 --- MType NED morphological classification where
available, or [new classification]
131-134 I4 km/s RV ? Central radial velocity from our
ANU2.3mT/WiFeS data
(Sweet et al., in prep.)
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Note (1): Notes as follows:
* = sources that have been identified since SINGG release 1; for these we
give preliminary measurements performed using IRAF's APPHOT task. IRAF
is distributed by the National Optical Astronomy Observatories, which
are operated by the Association of Universities for Research in
Astronomy, Inc., under cooperative agreement with the National Science
Foundation (Tody 1993, ASP Conf. Ser., 52, P.173).
a = Our declination for J1250-20:S3 is 10arcsec different from the ESO
measurement, suggesting a problem with their search radius for this object
b = Only half of J2318-42a is within our FOV, so we use the NED position for
J2318-42a:S3
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 08-Jul-2014