J/ApJS/237/36 Merging dwarf galaxies in the local universe (Paudel+, 2018)
A catalog of merging dwarf galaxies in the local universe.
Paudel S., Smith R., Yoon S.J., Calderon-Castillo P., Duc P.-A.
<Astrophys. J. Suppl. Ser., 237, 36 (2018)>
=2018ApJS..237...36P 2018ApJS..237...36P
ADC_Keywords: Galaxies, nearby; Photometry, SDSS; Photometry, ultraviolet;
Redshifts; Morphology; Surveys; Galaxy catalogs
Keywords: galaxies: dwarf ; galaxies: evolution ; galaxies: interactions ;
galaxies: star formation
Abstract:
We present the largest publicly available catalog of interacting dwarf
galaxies. It includes 177 nearby merging dwarf galaxies of stellar
mass M*<1010M☉ and redshifts z<0.02. These galaxies are
selected by visual inspection of publicly available archival imaging
from two wide-field optical surveys (SDSS-III and the Legacy Survey),
and they possess low-surface-brightness features that are likely the
result of an interaction between dwarf galaxies. We list UV and
optical photometric data that we use to estimate stellar masses and
star formation rates. So far, the study of interacting dwarf galaxies
has largely been done on an individual basis, and lacks a sufficiently
large catalog to give statistics on the properties of interacting
dwarf galaxies, and their role in the evolution of low-mass galaxies.
We expect that this public catalog can be used as a reference sample
to investigate the effects of the tidal interaction on the evolution
of star formation, and the morphology/structure of dwarf galaxies. Our
sample is overwhelmingly dominated by star-forming galaxies, and they
are generally found significantly below the red sequence in the
color-magnitude relation. The number of early-type galaxies is only 3
out of 177. We classify them, according to observed
low-surface-brightness features, into various categories including
shells, stellar streams, loops, antennae, or simply interacting. We
find that dwarf-dwarf interactions tend to prefer the low-density
environment. Only 41 out of the 177 candidate dwarf-dwarf interaction
systems have giant neighbors within a sky-projected distance of 700kpc
and a line-of-sight radial velocity range ±700km/s, and compared to
the LMC-SMC, they are generally located at much larger sky-projected
distances from their nearest giant neighbors.
Description:
The 177 interactive dwarf galaxies are selected by visual inspection
of publicly available archival imaging from two wide-field optical
surveys (SDSS-III, Aihara+ 2011, II/306 --superseded by V/147 -- and
the DECam Legacy Survey 2016AAS...22831701B).
Additionally, we also search for the availability of deeper images in
various publicly available archives. In this regard, the archival
images of the CHFT were very helpful for visual confirmation of the
presence of low-surface-brightness features around dwarf galaxies.
For many galaxies (146 out of 177), we found there were GALEX all-sky
survey observations available (Martin+ 2005ApJ...619L...1M 2005ApJ...619L...1M).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 85 177 Physical properties of merging dwarf galaxies
table2.dat 51 177 Derived properties of merging dwarf galaxies
--------------------------------------------------------------------------------
See also:
B/cfht : Log of CFHT Exposures (CADC, 1979-)
VII/74 : Atlas of Peculiar Galaxies (Arp 1966)
VII/238 : HYPERLEDA. II. Homogenized HI data (Paturel+, 2003)
VIII/73 : HI Parkes All Sky Survey Catalogue (HIPASS) (Meyer+, 2004)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
J/AJ/117/75 : BR photom. in Coma, A2199 & AWM5 clusters (Conselice+, 1999)
J/ApJS/147/29 : BRHalpha data of blue compact dwarf gal. (Gil De Paz+, 2003)
J/AJ/130/2647 : Tidal features of 126 nearby red gal. (van Dokkum+, 2005)
J/AJ/133/791 : Spitzer photom. of normal & interacting gal. (Smith+, 2007)
J/AJ/136/2782 : Star formation efficiency in nearby galaxies (Leroy+, 2008)
J/ApJS/182/216 : Surface photometry of Virgo ellipticals (Kormendy+, 2009)
J/ApJ/706/599 : Hα and UV SFR in the local volume (Lee+, 2009)
J/MNRAS/447/1531 : HI data collection update (Courtois+, 2015)
J/MNRAS/446/120 : ATLAS3D project. XXIX (Duc+, 2015)
http://www.sdss.org/ : SDSS home page
http://legacysurvey.org/ : The Legacy Surveys home page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/177] Internal index number
5- 15 A11 --- ID Identifier (IdHHMMDDMM or IdHHMM-DDMM)
17- 25 F9.5 deg RAdeg Right Ascension decimal degrees (J2000)
27- 34 F8.5 deg DEdeg Declination in decimal degrees (J2000)
36- 41 F6.4 --- z [0.0006/0.02] Spectroscopic redshift from NED
43- 47 F5.2 mag gmag [9.2/18.7] Apparent g band AB magnitude (1)
49- 53 F5.2 mag rmag [9.3/18.4] Apparent r band AB magnitude (1)
55- 59 F5.2 mag FUVmag [10.8/21.7]? GALEX FUV band AB magnitude (1)
61- 65 F5.2 mag NUVmag [10.8/19.7]? GALEX NUV band AB magnitude (1)
67- 70 A4 --- Morph Morphological class of merging dwarf system (2)
72- 85 A14 --- Name Galaxy name from NED
--------------------------------------------------------------------------------
Note (1): The derived magnitudes were corrected for the Galactic extinction
using Schlafly & Finkbeiner (2011ApJ...737..103S 2011ApJ...737..103S), but not for
internal extinction.
Note (2): Morphological class as follows:
I = Interacting; two dwarf galaxies visibly distinct (69 occurrences)
IM = Interacting merged; two dwarf galaxies overlapping or the progenitor
is not distinct (23 occurrences)
IB = Interacting with a bridge connecting the two galaxies (8 occurrences)
A = Antenna (3 occurrences)
Sh = Presence of shell features (30 occurrences)
T = Tidal tail (30 occurrences)
S = Stellar stream (14 occurrences)
L = Loop (4 occurrences)
E = Extended tail (12 occurrences)
F = Filament (1 occurrence)
See section 2.2 and Figure 2 for further explanations.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/177] Internal index number
5- 9 F5.2 Mpc Dist [3.9/85.4] Adopted distance from NED (3)
11- 15 F5.2 mag g-r [-0.3/0.8] SDSS (g-r) color index
17- 22 F6.2 mag BMag [-20.1/-12.1] Absolute B band magnitude
24- 27 F4.2 [Msun] logM* [6.9/10] log stellar mass
29- 31 I3 --- M1:M2 [1/120]? Mass ratio of interacting galaxies
33- 38 F6.2 [Msun/yr] SFR [-35/0.7]? log star formation rate (4)
40- 44 F5.2 [Msun] logMHI [7.3/10.1]? log H I mass
46 I1 --- Sat [0/1]? Satellite code (1= Is a satellite or
0= Is not a satellite)
48- 51 I4 --- Ngh [0/118]? Number of neighbors within our
search criteria (5)
--------------------------------------------------------------------------------
Note (3): The distances to the galaxies are taken from NED. For those
where NED does not provide a redshift-independent distance, we
calculate it based on Hubble flow, assuming the cosmological
parameters defined in Section 1 (H0=71km/s/Mpc, Ωm=0.3, and
Ωλ=0.7). We use the python code, cosmocalc, available
in astropy, to calculate cosmological distances based on the radial
velocities. The radial velocities are not corrected for Virgo-centric
flow. See section 3.
Note (4): The SFRs are derived from the FUV fluxes applying a foreground
Galactic extinction correction (AFUV=7.9xE(B-V)). We use the equation
(SFR(M☉/yr)=1.4x10-28Lν(UV)(erg/s/Hz)). See section 3.
Note (5): For this work we characterize the surrounding environment by searching
for neighboring galaxies within a sky-projected distance of less than
700kpc, and a relative line-of-sight radial velocity of less than
±700km/s. See section 5.2.
--------------------------------------------------------------------------------
Acknowledgements:
Sanjaya Paudel [Center for Galaxy Evolution Research, Yonsei University]
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Oct-2018