J/A+A/424/79 Photometry and Metallicity in ABCG 209 galaxies (Mercurio+, 2004)
Transformations of galaxies in the environments of the cluster ABCG 209 at z∼0.2
Mercurio A., Busarello G., Merluzzi P., La Barbera F., Girardi M., Haines C.
<Astron. Astrophys. 424, 79 (2004)>
=2004A&A...424...79M 2004A&A...424...79M
ADC_Keywords: Clusters, galaxy ; Galaxies, photometry ; Galaxies, spectra ;
Redshifts
Keywords: Galaxy: evolution - Galaxy: fundamental parameters -
galaxies: stellar content - galaxies: clusters: individual: ABCG 209
Abstract:
We analyse the properties of galaxy populations in the rich Abell
cluster ABCG 209 at redshift z∼0.21, on the basis of spectral
classification of 102 member galaxies. We take advantage of available
structural parameters to study separately the properties of
bulge-dominated and disk-dominated galaxies. The star formation
histories of the cluster galaxy populations are investigated by using
line strengths and the 4000Å break, through a comparison to stellar
population synthesis models. The dynamical properties of different
spectral classes are examined in order to infer the past merging
history of ABCG 209. The cluster is characterized by the presence of
two components: an old galaxy population, formed very early
(z_f≳3.5), and a younger (z_f≳1.2) population of infalling galaxies.
We find evidence of a merger with an infalling group of galaxies
occurred 3.5-4.5Gyr ago. The correlation between the position of the
young H_delta-strong galaxies and the X-ray flux shows that the hot
intracluster medium triggered a starburst in this galaxy population
∼3Gyr ago.
Description:
Photometric data (table1.dat) were collected on November 1999 using
the CFH12K mosaic camera and spectroscopic data (table2.dat) have
been obtained in the multi-object spectroscopy (MOS) mode of ESO Multi
Mode Instrument at the ESO New Technology Telescoe (NTT) for 102
galaxies belonging to the cluster ABCG 209.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 85 102 Photometric parameters for 102 galaxies
table4.dat 172 102 *Spectral indices for 102 galaxies
--------------------------------------------------------------------------------
Note on table4.dat:
The equivalent width is defined by:
EW={Sum, i=1 to N}[(FCi-Fi)/FCi)*Δλ]
where F_i is the flux in the pixel i, N is the number of pixels in the
integration range, Δλ is the dispersion in Å/pixel and
FCi is the straight line fitted to the blue and the red
pseudo-continuum intervals, evaluated in the pixel i (pixels with
values more than 3σ away from the continuum level were rejected).
An index measured in magnitudes is:
Mag=-2.5log[1-EW/(λ1-λ2)]
where λ1 and λ2 are the wavelength limits of the feature
bandpass.
The errors of the equivalent width measurement are estimated from the
relation of Czoske et al. (2001A&A...372..391C 2001A&A...372..391C, Cat. J/A+A/372/391).
--------------------------------------------------------------------------------
See also:
J/A+A/397/431 : Redshifts of ABCG209 galaxies (Mercurio+, 2003)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Running number
6- 7 I2 h RAh Right ascension (J2000.0)
10- 11 I2 min RAm Right ascension (J2000.0)
14- 18 F5.2 s RAs Right ascension (J2000.0)
22 A1 --- DE- Declination sign (J2000.0)
23- 24 I2 deg DEd Declination (J2000.0)
27- 28 I2 arcmin DEm Declination (J2000.0)
31- 34 F4.1 arcsec DEs Declination (J2000.0)
38- 42 F5.2 mag Rmag R-band Kron magnitude corrected for Galactic
extinction (1)
46- 49 F4.2 mag e_Rmag rms uncertainty on the R-band Kron magnitude
determination (2)
52- 55 F4.2 mag B-R B-R colour index
59- 62 F4.2 mag e_B-R rms uncertainty on the color determination (2)
65- 70 F6.4 --- z heliocentric corrected redshift
74- 79 F6.4 --- e_z rms uncertainty on the redshift
82- 84 F3.1 --- n Sersic index
--------------------------------------------------------------------------------
Note (1): Correction for foreground Galactic extinction according to
Schlegel et al. (1998ApJ...500..525S 1998ApJ...500..525S) corresponds to the centre of cluster
Note (2): Uncertainties in magnitudes and colours are rounded to the
second decimal place.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Running number
5- 8 F4.2 --- D4000 ? Strength of the 4000Å break
10- 13 F4.2 --- e_D4000 ? rms uncertainty on the 4000Å break
measurement
15- 19 F5.1 0.1nm EW[OII] ? [OII] equivalent width (1)
21- 23 F3.1 0.1nm e_EW[OII] ? rms uncertainty on OII equivalent width
26- 29 F4.1 0.1nm EWHdA Hδ,A equivalent width
31- 33 F3.1 0.1nm e_EWHdA rms uncertainty on Hδ,A equivalent width
35- 39 F5.1 0.1nm EWHgA Hγ,A equivalent width
41- 43 F3.1 0.1nm e_EWHgA rms uncertainty on Hγ,A equivalent width
46- 49 F4.1 0.1nm EWFe4531 Fe4531 equivalent width
51- 53 F3.1 0.1nm e_EWFe4531 rms uncertainty on Fe4531 equivalent width
55- 59 F5.1 0.1nm EWHb Hβ equivalent width
61- 63 F3.1 0.1nm e_EWHb rms uncertainty on H_beta equivalent width
65- 69 F5.1 0.1nm EW[OIII] Equivalent width of [OIII]
71- 73 F3.1 0.1nm e_EW[OIII] rms uncertainty on [OIII] equivalent width
75- 79 F5.1 0.1nm EWFe5015 Fe5015 equivalent width
81- 83 F3.1 0.1nm e_EWFe5015 rms uncertainty on Fe5015 equivalent width
87- 90 F4.2 mag Mg1 Mg1 index
92- 95 F4.2 mag e_Mg1 rms uncertainty on Mg1 index
98-101 F4.2 mag Mg2 Mg2 index
103-106 F4.2 mag e_Mg2 rms uncertainty on Mg2 index
109-112 F4.1 0.1nm Mgb Mgb index
114-116 F3.1 0.1nm e_Mgb rms uncertainty on Mgb index
118-122 F5.1 0.1nm EWFe5270 Hβ equivalent width
124-126 F3.1 0.1nm e_EWFe5270 rms uncertainty on Fe5270 equivalent width
129-132 F4.1 0.1nm EWFe5335 Fe5335 equivalent width
134-136 F3.1 0.1nm e_EWFe5335 rms uncertainty on Fe5335 equivalent width
138-143 F6.1 0.1nm EWHa ? Hα equivalent width (1)
145-147 F3.1 0.1nm e_EWHa ? rms uncertainty on H_alpha equivalent width
150-158 A9 --- Class Spectral classification (2)
--------------------------------------------------------------------------------
Note (1): A value of '0.0' for the equivalent width for an emission-line
indicates that no emission is observed, whereas '---' indicates that
the equivalent width could not be measured as the line does not lie
within the available wavelength range.
Note (2): Spectral classification:
ELG: emission line galaxies;
HDS_blue: Hδ strong galaxies with blue colour;
HDS_red: Hδ strong galaxies with red colour;
P: passive evolving galaxies;
Ab-spirals: passive evolving disk-dominated galaxies (nSersic≤2).
Galaxy 62 presents very strong [OII], [OIII] and Hα emission,
that could suggest the presence of an AGN. However, our data do not
allow a reliable classification, leading us to exclude this object
from the analysis..
--------------------------------------------------------------------------------
Acknowledgements: Armata Mercurio
(End) Patricia Vannier [CDS] 04-Jun-2004