J/A+A/582/A21     Merging galaxies (mis)alignments  (Barrera-Ballesteros+, 2015)
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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    (SIMBAD/NED BibCode)
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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
    (PA_kin_, 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 ({delta}PA_kin_). 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 {delta}PA_kin_ are large for both samples.
    However, for a large fraction of interacting galaxies the ionized gas
    {delta}PA_kin_ 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{deg}, 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), 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
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  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

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(End)                                      Patricia Vannier [CDS]    15-Jan-2016
