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J/ApJS/181/548    X-shaped radio sources. II. New redshifts      (Cheung+, 2009)
FIRST "Winged" and X-shaped radio source candidates.
II. New redshifts.
    Cheung C.C., Healey S.E., Landt H., Kleijn G.V., Jordan A.
   <Astrophys. J. Suppl. Ser., 181, 548-556 (2009)>
   =2009ApJS..181..548C
ADC_Keywords: Galaxies, radio ; Redshifts ; Spectroscopy

Keywords: galaxies: active - galaxies: distances and redshifts
          quasars: general

Abstract:
    We reported optical spectroscopic observations of X-shaped radio
    sources with the Hobby-Eberly Telescope and Multiple-Mirror Telescope,
    focused on the sample of candidates from the FIRST survey presented in
    Paper I (Cheung, 2007, Cat. J/AJ/133/2097). A total of 27 redshifts
    were successfully obtained, 21 of which are new, including a newly
    identified candidate source of this type which is presented here. With
    these observations, the sample of candidates from the previous paper
    is over 50% spectroscopically identified. Two new broad emission-lined
    X-shaped radio sources are revealed, while no emission lines were
    detected in about one-third of the observed sources; a detailed study
    of the line properties is deferred to a future paper. Finally, to
    explore their relation to the Fanaroff-Riley division, the radio
    luminosities and host galaxy absolute magnitudes of a
    spectroscopically identified sample of 50 X-shaped radio galaxies are
    calculated to determine their placement in the Owen-Ledlow plane.

Description:
    This paper presents observations with the 9.2m Hobby-Eberly Telescope
    (HET) at the McDonald Observatory in 2006 and 2007 under a
    queue-observing mode and with the 6.5m Multiple-Mirror Telescope
    (MMT) at Mt. Hopkins Observatory in a two-night run in 2007 February.
    An observation of one object (J0702+5002) was obtained earlier with
    the 2.7m Harlan J. Smith Telescope (HJST) at the McDonald
    Observatory. A summary of the observations is presented in Table1.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1.dat        52       27   Observation log and measured redshifts
table2.dat        49       50   Parameters of spectroscopically identified
                             X-shaped radio galaxy sample


See also:
 J/AJ/133/2097 : FIRST "Winged" & X-shaped radio source candidates (Cheung 2007)
 J/PASP/97/932 : 3CR Source Identifications (Spinrad+, 1985)


Byte-by-byte Description of file: table1.dat

   Bytes Format Units       Label     Explanations

   1-  3  A3    ---         Seq       Catalog number in Paper I ([C2007] NNN or
                                      XNN in Simbad) (G1)
   5- 14  A10   ---         [C2007]   JHHMM-DDMM (J2000) name
  16- 19  F4.1  mag         mag       Optical magnitude predominantly from
                                       Paper I, see summary in table2.
  21- 24  A4    ---         Tel       Telescope used (2)
  26- 35  A10  "YYYY/MM/DD" ObsDate   Observation date
  37- 40  I4    s           Exp       Total exposure time
  42- 46  F5.3  ---         z         Measured redshift
  48- 50  A3    ---         n_z       Absorption (abs) or emission (em) feature
      52  A1    ---         f_z       Note on redshift (3)

Note (2): Telescopes as follows:
    HET = Hobby-Eberly Telescope;
   HJST = Harlan J. Smith Telescope;
    MMT = Multi-Mirror Telescope.
Note (3): Note as follows:
   1 = redshift previously known, the new spectra tend to be of higher quality
       than the previously obtained ones, and the redshifts we measured are
       consistent (Δz<0.005) with the published values for all six
       sources (see Section 3.1),
   2 = redshift reported in Paper I (Cheung, 2007, Cat. J/AJ/133/2097) and
       the spectrum is now presented,
   3 = new FIRST X-shaped radio source candidate not presented in Paper I and
       described in Appendix B: FIRST J1018+2914 (4C+29.38, B2 1015+29)
       identified with SDSS J101827.09+291420.3,
   4 = tentative redshift due to relatively low S/N(∼5) of the spectrum,
   5 = new redshift superseding previous estimate for two objects (see
       Section 3.2).


Byte-by-byte Description of file: table2.dat

   Bytes Format Units   Label     Explanations

   1-  3  A3    ---     Seq       Catalog number in Paper I ([C2007] NNN or
                                  XNN in Simbad) (G1)
   5- 14  A10   ---     [C2007]   JHHMM+DDMM (J2000) name
  16- 19  F4.1  mag     mag       Observed optical magnitude (1)
      20  A1    ---     n_mag     [a-g] Magnitude band (2)
  22- 27  F6.4  ---     z         Redshift (3)
  29- 32  F4.2  ---     Kcor      K-corrections (4)
  34- 37  F4.2  ---     Av        Extinction corrections adopting R- and V-band
                                  values based on Schlegel et al.
                                  (1998ApJ...500..525S) maps
  39- 43  F5.2  [W/Hz] [L1.4GHz]  Logarithm of the total source radio luminosity
                                  at 1.4GHz. (5)
  45- 49  F5.1  mag     RMAG      Absolute R-band magnitude (6)

Note (1): The observed optical magnitudes are predominantly SDSS r-band values
          unless otherwise indicated with a flag (See n_mag column).
Note (2): Flags for less accurate (by as much as ∼0.5-1mag) known X-shaped
          radio objects as follows:
      a = Cousins R-band magnitude (Wold et al., 2007A&A...470..531W)
      b = Cousins R-band magnitude (Govoni et al., 2000A&AS..143..369G)
      c = Cousins R-band magnitude (USNO-B1 catalog, Cat. I/284,
          Monet et al., 2003)
      d = V-band magnitude (de Vaucouleurs et al., 1991RC3v9.C......0D)
      e = V-band magnitude (Smith & Heckman, 1989ApJS...69..365S)
      f = V-band magnitude (Spinrad et al., 1985, Cat. J/PASP/97/932)
      g = R-band value from the USNO-B1 catalog (for candidate sources)
Note (3): Redshifts are gathered from Paper I (Tables 1 and 2 therein;
     Cheung, 2007, Cat. J/AJ/133/2097) and Table 1 of this paper and are
     listed here for convenience.
Note (4): K-corrections adopted based on R-band values from Fukugita et
     al., 1995PASP..107..945F as tabulated in Urry et al.,
     2000ApJ...532..816U. In the few cases where V-band measurements were
     used (all z<0.2), the additional uncertainty due to utilizing the
     K-correction at R-band is negligible in comparison to the uncertainty
     in the published magnitudes.
Note (5): The radio fluxes used were tabulated in Paper I (Tables 1 and 2
     therein; Cheung, 2007, Cat. J/AJ/133/2097).
Note (6): Absolute R-band magnitude with K- and extinction corrections
     applied. Transformations assumed colors of r-R=0.25 and V-R=0.61,
     appropriate for giant ellipticals (Fukugita et al.,
     1995PASP..107..945F).


Global Notes:

Note (G1): Catalog number based on entry order in Table 1 (prepended
     with X) and Table 2 of Paper I (Cheung, 2007, Cat. J/AJ/133/2097,
     [C2007] NNN in Simbad) containing the lists of the known (XNN) and
     candidate (NN) X-shaped radio sources, respectively.


History:
    From electronic version of the journal

References:
    Cheung C.C. Paper I. 2007AJ....133.2097C; Cat. J/AJ/133/2097
(End)                                     Emmanuelle Perret [CDS]    02-Nov-2009