J/ApJ/819/73 Metallicity evolution of COSMOS BCD sample (Lian+, 2016)
The metallicity evolution of blue compact dwarf galaxies from the intermediate
redshift to the local universe.
Lian J., Hu N., Fang G., Ye C., Kong X.
<Astrophys. J., 819, 73 (2016)>
=2016ApJ...819...73L 2016ApJ...819...73L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, spectra ; Equivalent widths ; Redshifts ; Extinction ;
Abundances
Keywords: galaxies: dwarf - galaxies: evolution -
galaxies: fundamental parameters - galaxies: star formation
Abstract:
We present oxygen abundance measurements for 74 blue compact dwarf (BCD)
galaxies in the redshift range of [0.2, 0.5] using the strong-line
method. The spectra of these objects are taken using Hectospec on the
Multiple Mirror Telescope. More than half of these BCDs had dust
attenuation corrected using the Balmer decrement method. For
comparison, we also selected a sample of 2023 local BCDs from the
Sloan Digital Sky Survey (SDSS) database. Based on the local and
intermediate-z BCD samples, we investigated the cosmic evolution of
the metallicity, star formation rate (SFR), and Dn(4000) index.
Compared with local BCDs, the intermediate-z BCDs had a systematically
higher R23 ratio but a similar O32 ratio. Interestingly, no
significant deviation in the mass-metallicity (MZ) relation was found
between the intermediate-z and local BCDs. Besides the metallicity,
the intermediate-z BCDs also exhibited an SFR distribution that was
consistent with local BCDs, suggesting a weak dependence on redshift.
The intermediate-z BCDs seemed to be younger than the local BCDs with
lower Dn(4000) index values. The insignificant deviation in the
mass-metallicity and mass-SFR relations between intermediate-z and
local BCDs indicates that the relations between the global parameters
of low-mass compact galaxies may be universal. These results from
low-mass compact galaxies could be used to place important
observational constraints on galaxy formation and evolution models.
Description:
To study low-mass galaxies outside the local universe, we selected a
blue compact dwarf (BCD) sample at intermediate redshift in the Cosmic
Evolution Survey (COSMOS) deep field and then performed followup
spectroscopic observation using Hectospec on the Multiple Mirror
Telescope (MMT). We selected the BCD sample from a public Ks selected
catalog of the COSMOS field (Muzzin et al. 2013, J/ApJS/206/8).
The observations of these BCDs using the Hectospec/MMT were carried out
in 2015 February. Each fiber has a diameter of 1.5" (corresponding to
5 kpc at z=0.2) and covers most of the light of BCDs at intermediate
redshift.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 85 74 Emission Line Measurements of COSMOS BCD Sample
table2.dat 42 74 Physical Properties of COSMOS BCD Sample
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See also:
J/ApJS/147/29 : BRHalpha data of blue compact dwarf galaxies
(Gil De Paz+, 2003)
J/A+A/429/115 : JHK' photometry of Blue Compact Dwarf Galaxies (Noeske+, 2005)
J/A+A/434/887 : HI data of blue compact dwarf galaxies (Huchtmeier+, 2005)
J/ApJS/156/345 : Surface photometry of BCD galaxies (Gil de Paz+, 2005)
J/ApJS/206/8 : COSMOS/UltraVISTA Ks-selected catalogs v4.1 (Muzzin+, 2013)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- ID [1/74] Source identification number
4- 5 I2 h RAh Hour of Right Ascension (J2000)
7- 8 I2 min RAm Minute of Right Ascension (J2000)
10- 14 F5.2 s RAs Second of Right Ascension (J2000)
16 A1 --- DE- Sign of the Declination (J2000)
17- 18 I2 deg DEd Degree of Declination (J2000)
20- 21 I2 arcmin DEm Arcminute of Declination (J2000)
23- 26 F4.1 arcsec DEs Arcsecond of Declination (J2000)
28- 33 F6.1 10-21W/m2 F3727 Flux of [OII]λ3727 line
(in 10-18erg/s/cm2)
35- 37 F3.1 10-21W/m2 e_F3727 Uncertainty in F3727
39- 43 F5.1 10-21W/m2 FHg ? Hγ line flux
45- 47 F3.1 10-21W/m2 e_FHg ? Uncertainty in FHg
49- 53 F5.1 10-21W/m2 FHb Hβ line flux
55- 57 F3.1 10-21W/m2 e_FHb Uncertainty in FHb
59- 63 F5.1 0.1nm EW(Hb) Equivalent width of Hβ (Å)
65- 70 F6.1 10-21W/m2 F4959 Flux of [OIII]λ4959 line
(in 10-18erg/s/cm2)
72- 74 F3.1 10-21W/m2 e_F4959 Uncertainty in F4959
76- 81 F6.1 10-21W/m2 F5007 Flux of [OIII]λ5007 line
(in 10-18erg/s/cm2)
83- 85 F3.1 10-21W/m2 e_F5007 Uncertainty in F5007
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- ID [1/74] Source identification number
4- 8 F5.3 --- z Redshift
10- 12 F3.1 mag Av Dust extinction
13 A1 --- n_Av [s] Note on Av (1)
15- 18 F4.2 [Msun] logM* Log of stellar mass
20- 23 F4.2 --- 12+log(O/H) Oxygen abundance
25- 28 F4.2 --- e_12+log(O/H) Uncertainty in 12+log(O/H)
30- 33 F4.2 [Msun/yr] log(SFR) Log of star formation rate (2)
35- 38 F4.2 [Msun/yr] e_log(SFR) Uncertainty in log(SFR)
40- 42 F3.1 --- Dn(4000) ? Dn(4000) index (3)
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Note (1): Note as follows:
s = Dust attenuation AV from SED fitting.
Note (2): The listed SFR are not corrected for burst age which can be done by
combining the EW(Hb) listed in Table 1 and Equation (5) in
Izotov et al. (2015MNRAS.451.2251I 2015MNRAS.451.2251I).
Note (3): We calculated the 4000 Å break [i.e., Dn(4000) index] based on
the definition of Balogh et al. (1999ApJ...527...54B 1999ApJ...527...54B).
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 01-Feb-2018