J/A+A/433/497  Nearby early-type galaxies with ionized gas. I. (Rampazzo+, 2005)
================================================================================
Nearby early-type galaxies with ionized gas.
I. Line-strength indices of the underlying stellar population.
    Rampazzo R., Annibali F., Bressan A., Longhetti M., Padoan F.,
    Zeilinger W.W.
   <Astron. Astrophys. 433, 497 (2005)>
   =2005A&A...433..497R
================================================================================
ADC_Keywords: Galaxies, nearby ; Galaxies, spectra ; Equivalent widths
Keywords: galaxies: elliptical and lenticular, cD -
          galaxies: fundamental parameters - galaxies: formation -
          galaxies: evolution

Abstract:
    With the aim of building a data-set of spectral properties of well
    studied early-type galaxies showing emission lines, we present
    intermediate resolution spectra of 50 galaxies in the nearby Universe.
    The sample, which covers several of the E and S0 morphological
    sub-classes, is biased toward objects that might be expected to have
    ongoing and recent star formation, at least in small amounts, because
    of the presence of the emission lines. The emission is expected to
    come from the combination of active galactic nuclei and star formation
    regions within the galaxies. Sample galaxies are located in
    environments corresponding to a broad range of local galaxy densities,
    although predominantly in low density environments.

    Our long-slit spectra cover the 3700-7250{AA} wavelength range with a
    spectral resolution of approximately 7.6{AA} at 5550{AA}. The specific
    aim of this paper, and our first step in the investigation, is to map
    the underlying galaxy stellar population by measuring, along the slit
    positioned along the galaxy major axis, line-strength indices at
    several, homogeneous galacto-centric distances.

    For each object we extracted 7 luminosity-weighted apertures (with
    radii 1.5", 2.5", 10", r_e/10_, r_e/8_, r_e/4_ and r_e/2_) corrected for
    the galaxy ellipticity and 4 gradients (0<r<r_e/16_, r_e/16_<r<r_e/8_,
    r_e/8_<r<r_e/4_ and r_e/4_<r<r_e/2_). For each aperture and gradient 
    we measured 25 line-strength indices: 21 of the set defined by the
    Lick-IDS ``standard'' system (Trager et al., 1998, Cat. J/ApJS/116/1)
    and 4 introduced by Worthey & Ottaviani (1997, Cat. J/ApJS/111/377).
    Line-strength indices have been transformed to the Lick-IDS system.
    Indices derived then include H{beta}, Mg_1_, Mg_2_, Mgb, MgFe, Fe5270,
    Fe5335 commonly used in classic index-index diagrams.

    The paper introduces the sample, presents the observations, describes
    the data reduction procedures, the extraction of apertures and
    gradients, the determination and correction of the line-strength
    indices, the procedure adopted to transform them into the Lick-IDS
    System and the procedures adopted for the emission correction. We
    finally discuss the comparisons between our dataset and line-strength
    indices available in the literature.

    A significant fraction, about 60%, of galaxies in the present sample
    has one previous measurement in the Lick-IDS system but basically
    restricted within the r_e/8_ region. Line-strength measures obtained
    both from apertures and gradients outside this area and within the
    r_e/8_ region, with the present radial mapping, are completely new.

File Summary:
--------------------------------------------------------------------------------
 FileName   Lrecl  Records   Explanations
--------------------------------------------------------------------------------
ReadMe         80        .   This file
table1.dat    106       50   Overview of the observed sample
table6.dat     31      336   H{beta} corrections for apertures
table7.dat     31      192   H{beta} corrections for gradients
table9.dat    385      336   Fully corrected Line-strength indices
                              for the apertures
table10.dat   385      192   Fully corrected Line-strength indices
                              for the gradients
--------------------------------------------------------------------------------

See also:
  J/A+A/445/79 : Nearby early-type gal. with ionized gas. II (Annibali+, 2006)
 J/A+A/463/455 : Nearby early-type gal. with ionized gas. III (Annibali+ 2007)
 J/A+A/519/A40 : Nearby early-type gal. with ionized gas. IV (Annibali+, 2010)
   
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
   Bytes Format Units   Label       Explanations
--------------------------------------------------------------------------------
   1-  7  A7    ---     Galaxy      Galaxy designation
  10- 11  I2    h       RAh         Right Ascension J2000 (hours)
  13- 14  I2    min     RAm         Right Ascension J2000 (minutes)
  16- 19  F4.1  s       RAs         Right Ascension J2000 (seconds)
      21  A1    ---     DE-         Declination J2000 (sign)
  22- 23  I2    deg     DEd         Declination J2000 (degrees)
  25- 26  I2    arcmin  DEm         Declination J2000 (minutes)
  28- 29  I2    arcsec  DEs         Declination J2000 (seconds)
  32- 44  A13   ---     MType(RSA)  Morphological type from RSA (Cat. VII/51)
  46- 58  A13   ---     MType(RC3)  Morphological type from RC3 (Cat. VII/155)
  62- 64  I3    deg     PA          ? Position angle of the isophotes
  66- 70  F5.2  mag     B0mag       Total corrected blue magnitude
  73- 76  F4.2  mag     B-V         ? Total corrected (B-V) color
  79- 82  F4.2  mag     U-B         ? Total corrected (U-B) color
  86- 89  I4    km/s    Vel         Heliocentric systemic velocity 
                                     (from Hypercat)
  91- 94  F4.1  arcmin  re          Effective radius
  97-100  F4.2  Mpc-3   rho         ? Richness of the environment (gal.Mpc^-3^)
 103-106  F4.2  ---     eps         Average ellipticity (1-b/a)
--------------------------------------------------------------------------------

Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
   Bytes Format Units   Label       Explanations
--------------------------------------------------------------------------------
   1-  7  A7    ---     Galaxy      Galaxy designation
       9  I1    ---     Aperture    Aperture code (G1)
  12- 18  F7.3  0.1nm   EWO[III]    Equivalent width [OIII]
      23  I1    ---     Qual        Quality of the measure (G1)
  25- 31  F7.3  0.1nm   EWH{alpha}  Equivalent width H{alpha}
--------------------------------------------------------------------------------

Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
   Bytes Format Units   Label       Explanations
--------------------------------------------------------------------------------
   1-  7  A7    ---     Galaxy      Galaxy designation
       9  I1    ---     Gradient    Gradient code (G1)
  12- 18  F7.3  0.1nm   EWO[III]    Equivalent width [OIII]
      23  I1    ---     Qual        Quality of the measure (G1)
  25- 31  F7.3  0.1nm   EWH{alpha}  Equivalent width H{alpha}
--------------------------------------------------------------------------------

Byte-by-byte Description of file: table9.dat table10.dat
--------------------------------------------------------------------------------
   Bytes Format Units     Label     Explanations
--------------------------------------------------------------------------------
   1-  7  A7    --        Galaxy    Galaxy designation
       9  I1    --        iz        [0/6] Indicates the aperture (table9)
                                          or the gradient (table10) code (G2)
  11- 15  F5.3  ---       r1        Relative aperture radius (lower limit)
  17- 21  F5.3  ---       r2        Relative aperture radius (upper limit)
  23- 27  F5.3  ---       rwl       Luminosity weighted radius
  29- 32  F4.1  arcsec    req       Adopted equivalent radius
  33- 34  A2    ---       ---       [00]
  36- 41  F6.3  mag       CN1       Line-strength index of CN1
  43- 48  F6.3  mag       CN2       Line-strength index of CN2
  50- 55  F6.3  0.1nm     Ca4227    Line-strength index of Ca4227
  57- 62  F6.3  0.1nm     G4300     Line-strength index of G4300
  64- 69  F6.3  0.1nm     Fe4383    Line-strength index of Fe4383
  71- 76  F6.3  0.1nm     Ca4455    Line-strength index of Ca4455
  78- 83  F6.3  0.1nm     Fe4531    Line-strength index of Fe4531
  85- 90  F6.3  0.1nm     Fe4668    Line-strength index of Fe4668
  92- 97  F6.3  0.1nm     Hbeta     Line-strength index of H{beta}
  99-105  F7.3  0.1nm     Fe5015    Line-strength index of Fe5015
 107-112  F6.3  mag       Mg1       Line-strength index of Mg1
 114-119  F6.3  mag       Mg2       Line-strength index of Mg2
 121-126  F6.3  0.1nm     Mgb       Line-strength index of Mgb
 128-133  F6.3  0.1nm     Fe5270    Line-strength index of Fe5270
 135-140  F6.3  0.1nm     Fe5335    Line-strength index of Fe5335
 142-147  F6.3  0.1nm     Fe5406    Line-strength index of Fe5406
 149-154  F6.3  0.1nm     Fe5709    Line-strength index of Fe5709
 156-161  F6.3  0.1nm     Fe5782    Line-strength index of Fe5782
 163-168  F6.3  0.1nm     NaD       Line-strength index of NaD
 170-175  F6.3  mag       TiO1      Line-strength index of TiO1
 177-182  F6.3  mag       TiO2      Line-strength index of TiO2
 184-189  F6.3  0.1nm     HdeltaA   Line-strength index of H{delta}A
 191-197  F7.3  0.1nm     HgammaA   Line-strength index of H{gamma}A
 199-204  F6.3  0.1nm     HdeltaF   Line-strength index of H{delta}F
 206-211  F6.3  0.1nm     HgammaF   Line-strength index of H{gamma}F
 213-217  F5.3  mag     e_CN1       Error on Line-strength index of CN1
 219-224  F6.3  mag     e_CN2       Error on Line-strength index of CN2
 226-231  F6.3  0.1nm   e_Ca4227    Error on Line-strength index of Ca4227
 233-238  F6.3  0.1nm   e_G4300     Error on Line-strength index of G4300
 240-245  F6.3  0.1nm   e_Fe4383    Error on Line-strength index of Fe4383
 247-252  F6.3  0.1nm   e_Ca4455    Error on Line-strength index of Ca4455
 254-259  F6.3  0.1nm   e_Fe4531    Error on Line-strength index of Fe4531
 261-266  F6.3  0.1nm   e_Fe4668    Error on Line-strength index of Fe4668
 268-273  F6.3  0.1nm   e_Hbeta     Error on Line-strength index of H{beta}
 275-280  F6.3  0.1nm   e_Fe5015    Error on Line-strength index of Fe5015
 282-287  F6.3  mag     e_Mg1       Error on Line-strength index of Mg1
 289-294  F6.3  mag     e_Mg2       Error on Line-strength index of Mg2
 296-301  F6.3  0.1nm   e_Mgb       Error on Line-strength index of Mgb
 303-308  F6.3  0.1nm   e_Fe5270    Error on Line-strength index of Fe5270
 310-315  F6.3  0.1nm   e_Fe5335    Error on Line-strength index of Fe5335
 317-322  F6.3  0.1nm   e_Fe5406    Error on Line-strength index of Fe5406
 324-329  F6.3  0.1nm   e_Fe5709    Error on Line-strength index of Fe5709
 331-336  F6.3  0.1nm   e_Fe5782    Error on Line-strength index of Fe5782
 338-343  F6.3  0.1nm   e_NaD       Error on Line-strength index of NaD
 345-350  F6.3  mag     e_TiO1      Error on Line-strength index of TiO1
 352-357  F6.3  mag     e_TiO2      Error on Line-strength index of TiO2
 359-364  F6.3  0.1nm   e_HdeltaA   Error on Line-strength index of H{delta}A
 366-371  F6.3  0.1nm   e_HgammaA   Error on Line-strength index of H{gamma}A
 373-378  F6.3  0.1nm   e_HdeltaF   Error on Line-strength index of H{delta}F
 380-385  F6.3  0.1nm   e_HgammaF   Error on Line-strength index of H{gamma}F
--------------------------------------------------------------------------------

Global notes:
Note (G1): When the emission is lower than the variance the quality is 
    set to 0. When the emission is between 1 and 2{sigma}_{lambda}_ or
    larger than 2{sigma}_{lambda}_ the quality is set to 1 and 2
    respectively.

Note (G2): In tables 6 and 9, the aperture code is the following:
       0: r = 1.5"
       1: r = 2.5"
       2: r = 10"
       3: r = r_e_/10 
       4: r = r_e_/8 
       5: r = r_e_/4 
       6: r = r_e_/2 
     In table 7 and 10, the gradient code is:
       0:       0  < r < r_e_/16 
       1: r_e_/16  < r < r_e_/8 
       2: r_e_/8   < r < r_e_/4 
       3: r_e_/4   < r < r_e_/2 
--------------------------------------------------------------------------------

Acknowledgements: Roberto Rampazzo, rampazzo(at)pd.astro.it
================================================================================
(End)                                        Patricia Vannier [CDS]  18-Jan-2005