J/A+A/582/A21 Merging galaxies (mis)alignments (Barrera-Ballesteros+, 2015)
Tracing kinematic (mis)alignments in CALIFA merging galaxies.
Stellar and ionized gas kinematic orientations at every merger stage.
Barrera-Ballesteros J.K., Garcia-Lorenzo B., Falcon-Barroso J.,
Van De Ven G., Lyubenova M., Wild V., Mendez-Abreu J., Sanchez S.F.,
Marquez I., Masegosa J., Monreal-Ibero A., Ziegler B., Del Olmo A.,
Verdes-Montenegro L., Garcia-Benito R., Husemann B., Mast D., Kehrig C.,
Iglesias-Paramo J., Marino R.A., Aguerri J.A.L., Walcher C.J.,
Vilchez J.M., Bomans D.J., Cortijo-Ferrero C., Gonzalez Delgado R.M.,
Bland-hawthorn J., Mcintosh D.H., Bekeraite S., (the Califa collaboration)
<Astron. Astrophys., 582, A21-21 (2015)>
=2015A&A...582A..21B 2015A&A...582A..21B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, peculiar ; Radial velocities
Keywords: galaxies: evolution - galaxies: interactions -
galaxies: kinematics and dynamics - galaxies: statistics
Abstract:
We present spatially resolved stellar and/or ionized gas kinematic
properties for a sample of 103 interacting galaxies, tracing all
merger stages: close companions, pairs with morphological signatures
of interaction, and coalesced merger remnants. In order to distinguish
kinematic properties caused by a merger event from those driven by
internal processes, we compare our galaxies with a control sample of
80 non-interacting galaxies. We measure for both the stellar and the
ionized gas components the major (projected) kinematic position angles
(PAkin, approaching and receding) directly from the velocity
distributions with no assumptions on the internal motions. This method
also allow us to derive the deviations of the kinematic PAs from a
straight line (δPAkin). We find that around half of the
interacting objects show morpho-kinematic PA misalignments that cannot
be found in the control sample. In particular, we observe those
misalignments in galaxies with morphological signatures of
interaction. On the other hand, the level of alignment between the
approaching and receding sides for both samples is similar, with most
of the galaxies displaying small misalignments. Radial deviations of
the kinematic PA orientation from a straight line in the stellar
component measured by δPAkin are large for both samples.
However, for a large fraction of interacting galaxies the ionized gas
δPAkin is larger than the typical values derived from isolated
galaxies (48%), indicating that this parameter is a good indicator to
trace the impact of interaction and mergers in the internal motions of
galaxies. By comparing the stellar and ionized gas kinematic PA, we
find that 42% (28/66) of the interacting galaxies have misalignments
larger than 16°, compared to 10% from the control sample. Our
results show the impact of interactions in the motion of stellar and
ionized gas as well as the wide the variety of their spatially
resolved kinematic distributions. This study also provides a local
Universe benchmark for kinematic studies in merging galaxies at high
redshift.
Description:
The sample presented in this work was selected from 256 objects
observed until March 20131. These galaxies are part of the CALIFA
mother sample (hereafter CALIFA MS). We consider as objects in pairs
those galaxies with companions within a projected distance of 160kpc,
systemic velocity difference smaller than 300km/s, and a
difference in r-band magnitude smaller than 2mag (relative
distances, systemic velocities, and magnitudes were taken from NED3).
Observations were carried out using the PPAK instrument at Calar Alto
Observatory. Its main component consists of 331 fibers of 2.7"
diameter each, concentrated in a single hexagon bundle covering a FoV
of 74"x64", with a filling factor of ∼60%. Three dithering pointings
are taken for each object to reach a filling factor of 100% across the
entire FoV (see details in Husemann et al. 2013). The final data cube
consists of more than 4000 spectra at a sampling of 1"x1" per spaxel.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 39 103 Morphological parameters of the sample of
interacting CALIFA galaxies used in this study
tablea2.dat 101 103 Stellar kinematic properties of the interacting
sample selected for this study included in the
CALIFA survey
tablea3.dat 101 103 Ionized gas kinematic properties of the
interacting sample selected for this study
included in the CALIFA survey
tablea4.dat 26 103 Kinematic (mis)alignment between the stellar and
the ionised gas components for the galaxies
included in this study
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See also:
J/A+A/581/A103 : CALIFA survey across the Hubble sequence (Gonzalez+, 2015)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID CALIFA identification number (1)
6- 21 A16 --- Name Name
24- 26 A3 --- MType Morphological type from visual classification (2)
29 I1 --- IStage Interaction stage (3)
31 A1 --- --- [(]
32 I1 --- IStage2 ? Alternative interaction stage for galaxies
with uncertain interaction stage (3)
33 A1 --- --- [)]
35- 39 F5.2 [Msun] logMass Stellar mass (2)
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Note (1): For the objects not included in the CALIFA mother sample, we tag
them as the ID of the CALIFA companion plus 1000.
Note (2): see Walcher et al. (2014A&A...569A...1W 2014A&A...569A...1W), for details
Note (3): Interaction stage as follows:
0 = non-interacting galaxies
1 = objects include in a pair
2 = galaxy in a binary system with clear signatures of interaction
3 = merger remnant with evident tidal features
4 = merger remnant, respectively
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Byte-by-byte Description of file: tablea2.dat tablea3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ID CALIFA identification number
6- 9 I4 km/s Vsys ? Systemic velocity (1)
11- 12 I2 km/s e_Vsys ? rms uncertainty on Vsys
14- 15 I2 arcsec r ? Radius used to average the polar coordinates
of the positions from the lines of nodes
(see Sect. 2.5 for details)
17- 21 F5.1 deg PAmorph(r) ? Morphological PA inferred by fitting an
ellipse to an isophote at radius r in the
r-band SDSS imag
23- 26 F4.1 deg e_PAmorph(r) ? rms uncertainty on PAmorph(r)
28- 32 F5.1 deg PAkinApp ? Kinematic PA at radius r for the approaching
side (see Sect. 2.5 for details)
34- 37 F4.1 deg e_PAkinApp ? rms uncertainty on PAkinApp
39- 42 F4.1 deg dPAkinApp ? Standard deviation of Kinematic PA at radius
r for the approaching side
44- 47 F4.1 deg e_dPAkinApp ? rms uncertainty on dPAkinApp
49- 53 F5.1 deg PAkinRec ? Kinematic PA at radius r for the receding
side
55- 58 F4.1 deg e_PAkinRec ? rms uncertainty on PAkinRec
60- 63 F4.1 deg dPAkinRec ? Standard deviation of kinematic PA at radius
r for the receding side
65- 68 F4.1 deg e_dPAkinRec ? rms uncertainty on dPAkinRec
70- 73 F4.1 deg phim-kApp ? Morpho-kinematic misalignments for the
approaching side
75- 78 F4.1 deg e_phim-kApp ? rms uncertainty on phim-kApp
79 A1 --- n_phim-kApp [*] Note on phim-kApp (2)
81- 84 F4.1 deg phim-kRec ? Morpho-kinematic misalignments for the
receding side
86- 89 F4.1 deg e_phim-kRec ? rms uncertainty on phim-kRec
90 A1 --- n_phim-kRec [*] Note on phim-kRec (2)
92- 95 F4.1 deg phik-k ? Kinematic misalignment between the receding
and the approaching side
97-100 F4.1 deg e_phik-k ? rms uncertainty on phik-k
101 A1 --- n_phik-k [*] Note on phik-k (2)
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Note (1): Systemic velocity derived from integrated the line-of-sight velocities
in a 2.7" aperture centred in the kinematic centre.
Note (2): * for the objects where it is not possible to determine any kinematic
property using our method (see Sect. 2.5 for details).
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Byte-by-byte Description of file: tablea4.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID CALIFA identification number
6- 10 F5.1 deg phig-sApp ? Kinematic misalignment between the stellar
and ionised gas kinematic PA for the
approaching side
12- 15 F4.1 deg e_phig-sApp ? rms uncertainty on phig-sApp
17- 21 F5.1 deg phig-sRec ? Kinematic misalignment between the stellar
and ionised gas kinematic PA for the
receding side
23- 26 F4.1 deg e_phig-sRec ? rms uncertainty on phig-sApp
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 15-Jan-2016