J/A+A/553/A91 Halpha3 survey of Virgo and Coma galaxies (Fossati+, 2013)
Halpha3: an Hα imaging survey of HI selected galaxies from ALFALFA.
IV: The structure of galaxies in the Local and Coma Superclusters.
Fossati M., Gavazzi G., Savorgnan G., Fumagalli M., Boselli A.,
Gutierrez L., Hernandez Toledo H., Giovanelli R., Haynes M.P.
<Astron. Astrophys. 553, A91 (2013)>
=2013A&A...553A..91F 2013A&A...553A..91F
ADC_Keywords: Clusters, galaxy ; H I data ; Morphology
Keywords: galaxies: clusters: individual: Virgo -
galaxies: fundamental parameters -
galaxies: clusters: individual: Coma - galaxies: star formation
Abstract:
We present the analysis of the galaxy structural parameters from
Hα3, an Hα narrow-band imaging follow-up survey of ∼800
galaxies selected from the HI Arecibo Legacy Fast ALFA Survey
(ALFALFA) in the Local Supercluster, including the Virgo cluster, and
in the Coma Supercluster.
Taking advantage of Hα3 which provides the complete census of
the recent star-forming, HI-rich galaxies in the local universe, we
aim to investigate the structural parameters of both the young
(<10Myr) and the old (>1Gyr) stellar populations. By comparing the
sizes of these stellar components we investigated the spatial scale on
which galaxies are growing at the present cosmological epoch and the
role of the environment in quenching the star-formation activity. We
computed the concentration, asymmetry, and clumpiness (CAS) structural
parameters both for recently born and old stars. To quantify the sizes
we computed half-light radii and a new parameter dubbed EW/r based on
the half-light radius of the Hα Equivalent Width map.
To highlight the environmental perturbation, we adopt an updated
calibration of the HI-deficiency parameter that we use to divide the
sample in unperturbed and perturbed galaxies. The concentration index
computed in the r band depends on the stellar mass and on the Hubble
type, these variables being related since most massive galaxies are
bulge dominated thus most concentrated.
Going toward later spirals and irregulars both the concentration index
and the mass decrease along with the bulge-to-disk ratio. Blue Compact
dwarfs represent an exception since they have similar mass but they
are more concentrated than dwarf irregulars. The asymmetry and the
clumpiness increase along the spiral sequence up to Sc-Sd but they
decrease going toward dwarfs whose light distribution is smooth and
more symmetric.
When measured on Hα images, the CAS parameters do not exhibit obvious
correlations with Hubble type.
Irrespective of whether we used the ratio between effective radii or
the EW/r parameter, we found that the concentration index is the main
parameter that describes the current growth of isolated galaxies but,
for a fixed concentration, the stellar mass plays a second order role.
At the present epoch, massive galaxies are growing inside-out,
conversely the dwarfs are growing on the scale of their already
assembled mass.
Description:
Structural parameters for 742 late-type galaxies in the Local and Coma
Superclusters are presented. For each galaxy AGC and VCC (CGCG instead
of VCC for Coma) names, equatorial coordinates and concentration,
asymmetry and clumpiness computed in the r band are given. Where
possible we provide also the CAS parameters from Hα narrow-band
images, and half-light radii from the r band, Hα and EW(Hα)
maps.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 87 352 Structural parameters of Local Supercluster galaxies
tablea2.dat 87 390 Structural parameters of Coma Supercluster galaxies
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See also:
J/A+A/545/A16 : Halpha3. Catalog and SFR in Virgo cluster (Gavazzi+, 2012)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 6 I6 --- AGC ? AGC name
10- 13 I4 --- VCC ? VCC (Cat. J/AJ/90/1681) name
15- 16 I2 h RAh Right Ascension (J2000)
18- 19 I2 min RAm Right Ascension (J2000)
21- 24 F4.1 s RAs Right Ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
30- 31 I2 arcmin DEm Declination (J2000)
33- 34 I2 arcsec DEs Declination (J2000)
36- 40 F5.1 arcsec R.r ? r-band effective radius
42- 46 F5.1 arcsec R.Ha ? Hα effective radius
48- 52 F5.1 arcsec R.EW ? Effective radius computed from the Hα
Equivalent Width (EW) map
54- 57 F4.2 --- C.r [1.8/4.7] r-band concentration index (G1)
59- 63 F5.2 --- A.r [0/1] r-band asymmetry index (G2)
65- 69 F5.2 --- S.r [-0.2/1.4] r-band clumpiness index (G3)
72- 75 F4.2 --- C.Ha [0.2/6.5]? Hα concentration index (G1)
77- 81 F5.2 --- A.Ha [-0.03/1.24]? Hα asymmetry index (G2)
83- 87 F5.2 --- S.Ha [-0.6/3.0]? Hα clumpiness index (G3)
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- AGC ? AGC name
8- 13 I6 --- CGCG ? CGCG (Cat. VII/49) name
15- 16 I2 h RAh Right Ascension (J2000)
18- 19 I2 min RAm Right Ascension (J2000)
21- 24 F4.1 s RAs Right Ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
30- 31 I2 arcmin DEm Declination (J2000)
33- 34 I2 arcsec DEs Declination (J2000)
36- 40 F5.1 arcsec R.r ? r-band effective radius
42- 46 F5.1 arcsec R.Ha ? Hα effective radius
48- 52 F5.1 arcsec R.EW ? EW(Hα) effective radius
54- 57 F4.2 --- C.r [1.8/4.7] r-band concentration index (G1)
59- 63 F5.2 --- A.r [0/1] r-band asymmetry index (G2)
65- 69 F5.2 --- S.r [-0.2/1.4] r-band clumpiness index (G3)
72- 75 F4.2 --- C.Ha [0.2/6.5]? Hα concentration index (G1)
77- 81 F5.2 --- A.Ha [-0.03/1.24]? Hα asymmetry index (G2)
83- 87 F5.2 --- S.Ha [-0.6/3.0]? Hα clumpiness index (G3)
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Global Notes:
Note (G1): the concentration index measures the ratio of light within a
circular or elliptical inner aperture to the light within an outer
aperture. We adopt the Bershady et al. (2000AJ....119.2645B 2000AJ....119.2645B)
definition as the ratio of the circular radii containing 20% and 80%
of the total flux: C=5log(r(80%)/r(20%))
Note (G2): the asymmetry index is defined as the difference in flux between
the original image and the one rotated by 180° from its center,
normalized to the flux in the original image; see Conselice et al.
(2000ApJ...529..886C 2000ApJ...529..886C)
Note (G3): the clumpiness parameter S has been developped by Conselice
(2003ApJS..147....1C 2003ApJS..147....1C); it is close to 0 for ellipticals.
Acknowledgements:
Matteo Fossati, mfossati(at)mpe.mpg.de
References:
Gavazzi et al., Paper I, 2012A&A...545A..16G 2012A&A...545A..16G, Cat. J/A+A/545/A16
Gavazzi et al., Paper II, 2013A&A...553A..89G 2013A&A...553A..89G
Gavazzi et al., Paper III, 2013A&A...553A..90G 2013A&A...553A..90G
History:
* 15-May-2013: on-line version
* 13-Jan-2015: in tablea1, positions of AGC 221988 and AGC 224489 were
inverted. Correction from author.
(End) Patricia Vannier [CDS] 07-Mar-2013