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J/A+A/601/A95     Star-forming dwarfs at intermediate-z in VUDS (Calabro+, 2017)

Characterization of star-forming dwarf galaxies at 0. 1 ~< z ~< 0. 9 in VUDS: probing the low-mass end of the mass-metallicity relation. Calabro A., Amorin R., Fontana A., Perez-Montero E., Lemaux B.C., Ribeiro B., Bardelli S., Castellano M., Contini T., de Barros S., Garilli B., Grazian A., Guaita L., Hathi N.P., Koekemoer A.M., Le Fevre O., Maccagni D., Pentericci L., Schaerer D., Talia M., Tasca L.A.M., Zucca E. <Astron. Astrophys. 601, A95 (2017)> =2017A&A...601A..95C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Spectroscopy ; Abundances Keywords: galaxies: evolution - galaxies: high redshift - galaxies: dwarf - galaxies: abundances - galaxies: starbursts Abstract: We present emission line measurements and the main physical properties of a sample of 164 star-forming dwarf galaxies (SFDGs) in the VIMOS Ultra Deep Survey (VUDS, Le Fevre et al., 2015A&A...576A..79L). VUDS is one of the largest programs on the ESO-VLT with 640 hours of observing time, and covers a total of one square degree in three separate fields: COSMOS, ECDFS, and VVDS-02h. The spectroscopic observations were carried out at the VLT with the VIMOS Multi-Object Spectrograph (MOS) with two grisms (LRBLUE and LRRED) covering a wavelength range of 365<lambda<935nm at uniform spectral resolution of R=180 and R=210, respectively. The integration time (on-source) is ∼14-hours per target for each grism, which allows to detect the continuum at 850nm for iAB=25, and emission lines with an observed flux limit F=1.5*10-18erg/s/cm2 at S/N∼5. Redshift measurements in VUDS were performed using the EZ code (Garilli et al., 2010PASP..122..827G), both in automatic and manual modes (by two persons independently) for each spectrum. The overall redshift accuracy is dz/(1+z)=0.0005-0.0007. The spectra had already been fully calibrated in wavelength and flux by the VUDS team, which also did the sky subtraction. Emission lines fluxes and equivalent widths are measured manually on a one-by- one basis using the task 'splot' of IRAF by direct integration of the line profile after linear subtraction of the continuum. These fluxes are given in units of 10-18erg/s/cm2. The uncertainties in the line measurements were computed from the dispersion of values provided by multiple measurements adopting different possible band-passes (free of lines and strong residuals from sky subtraction) for the local continuum determination, which is fitted using a second order polynomial. No extinction correction has been applied to these fluxes. The EW measurements of Hγ, Hβ and Hα lines have been already corrected for absorption by +0.1nm for all galaxies, following Ly et al. (2014ApJ...780..122L). For each galaxy the reddening constant, c(Hβ), is presented. These values and their uncertainties have been derived from the Hα/Hβ or Hγ/Hβ ratios, whenever possible. We adopted the reddening constant from the best-fit SED, using the relations of Calzetti et al. (2000ApJ...533..682C), for (a) galaxies where the computation of c(Hβ) from emission lines is not possible because the lines are not present, or (b) the line ratios give a negative extinction correction (i.e., Hα/Hβ<2.82 or Hγ/Hβ<0.47, assuming Case B recombination with Te=2*104K, ne=100cm-3). Description: Stellar masses (Ms) and 1-sigma uncertainties have been derived from the SED fitting code Le Phare (Ilbert et al., 2006A&A...524A..76B). A Chabrier (2003PASP..115..763C) IMF and Calzetti et al. (2000ApJ...533..682C) extinction law are adopted, while the contribution of emission lines to the stellar templates have been considered following Ilbert et al. (2009ApJ..690..1236I). Typical 1-sigma uncertainties in Ms are ∼0.2dex and are obtained from the median of the probability distribution function (PDF). Thus, they do not account for possible systematic error (e.g., IMF variations). Star formation rates have been derived from Hα or Hβ luminosity (IMF from Chabrier et al. (2003PASP..115..763C) and assuming a theoretical ratio Hα/Hβ=2.82) following Kennicutt (1998ApJ...498..541K). Uncertainties in SFR account for the propagation of errors in line fluxes. Gas-phase metallicities, ionization parameters, and their uncertainties, have been derived using the code HII-CHI-mistry (HCm, Perez-Montero et al., 2014MNRAS.441.2663P), which is based on the comparison between a set of observed line ratios ([OII]3727,[OIII]4363,[OIII]5007,[NII]6584, [SII]6717+6731, all relative to Hβ) and the predictions of photoionization models. HCm provides abundances that are consistent with those derived from the direct method. Morphological type for each galaxy is based on HST-ACS F814W band images, available for COSMOS and ECDFS fields, and follows the criteria of Amorin et al. (2015A&A...578A.105A). The effective radius and axis ratio have been derived on the same images using GALFIT (Peng et al., 2002AJ....124..266P, 2010AJ....139.2097P) , following the methodology presented in Ribeiro et al. (2016A&A...593A..22R), in those cases when no error is found in the fitting procedure. The gas surface densities 'sgas' and total gas masses 'Mgas' were derived by inverting an assumedly non-variable Kennicutt-Schmidt (KS) law (Kennicutt & Evans, 2012ARA&A..50..531K) with exponent n=1.4. Then, gas fractions are calculated as: Mgas/(Mgas+Ms). For sgas and fgas, we should consider an uncertainty of at least 0.2-0.3dex (∼ a factor of two), which comes both from the uncertainties of the size and from the KS law. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tableb1.dat 56 164 Positions, redshifts and selection magnitudes tableb2.dat 183 164 Emission line fluxes and reddening tableb3.dat 103 164 Derived physical properties of SFDGs in VUDS
See also: J/A+A/568/L8 : VUDS extreme emission line 0.2≲z≲0.9 galaxies (Amorin+, 2014) J/A+A/572/A41 : VUDS Dicovery of a high-redshift protocluster (Lemaux+, 2014) Byte-by-byte Description of file: tableb1.dat
Bytes Format Units Label Explanations
1- 10 I10 --- VUDS VUDS ID number 12- 21 F10.6 deg RAdeg Right ascension (J2000.0) 23- 32 F10.6 deg DEdeg Declination (J2000.0) 34- 39 F6.4 --- z Spectroscopic redshift 41- 46 F6.3 mag imag Selection magnitude (i-band) (AB) 48- 54 F7.3 mag iMAG ?=-99.990 Rest-frame absolute magnitude in the i band (AB) 56 A1 --- Field [0-2] Field (1)
Note (1): VUDS field as follows: 0 = COSMOS 1 = ECDFS 2 = VVDS-02h
Byte-by-byte Description of file: tableb2.dat
Bytes Format Units Label Explanations
1- 10 I10 --- VUDS VUDS ID number 12- 16 F5.1 10-21W/m2 F(3727) ?=-9.9 [OII]3727 line flux 18- 21 F4.1 10-21W/m2 e_F(3727) ?=-9.9 Error in [OII]3727 line flux 24- 28 F5.1 0.1nm EW(3727) ?=-9.9 [OII]3727 EW 30- 34 F5.1 0.1nm e_EW(3727) ?=-9.9 Error in [OII]3727 EW 36- 39 F4.1 10-21W/m2 F(3868) ?=-9.9 [NeIII]3868 line flux 41- 44 F4.1 10-21W/m2 e_F(3868) ?=-9.9 Error in [NeIII]3868 line flux 46- 49 F4.1 10-21W/m2 F(Hg) ?=-9.9 Hγ line flux 51- 54 F4.1 10-21W/m2 e_F(Hg) ?=-9.9 Error in Hg line flux 56- 59 F4.1 10-21W/m2 F(4363) ?=-9.9 [OIII]4363 line flux 61- 64 F4.1 10-21W/m2 e_F(4363) ?=-9.9 Error in [OIII]4363 line flux 66- 70 F5.1 10-21W/m2 F(Hb) ?=-9.9 Hβ line flux 72- 75 F4.1 10-21W/m2 e_F(Hb) ?=-9.9 Error in Hb line flux 77- 81 F5.1 0.1nm EW(Hb) ?=-9.9 Hβ EW 83- 87 F5.1 0.1nm e_EW(Hb) ?=-9.9 Error in Hb EW 89- 93 F5.1 10-21W/m2 F(4959) ?=-9.9 [OIII]4959 line flux 95- 98 F4.1 10-21W/m2 e_F(4959) ?=-9.9 Error in [OIII]4959 line flux 100-104 F5.1 10-21W/m2 F(5007) ?=-9.9 [OIII]5007 line flux 106-109 F4.1 10-21W/m2 e_F(5007) ?=-9.9 Error in [OIII]5007 line flux 111-116 F6.1 0.1nm EW(5007) ?=-9.9 [OIII]5007 EW 118-122 F5.1 0.1nm e_EW(5007) ?=-9.9 Error in [OIII]5007 EW 124-128 F5.1 10-21W/m2 F(Ha) ?=-9.9 Hα line flux 130-133 F4.1 10-21W/m2 e_F(Ha) ?=-9.9 Error in Ha line flux 135-139 F5.1 0.1nm EW(Ha) ?=-9.9 Hα EW 141-145 F5.1 0.1nm e_EW(Ha) ?=-9.9 Error in Ha EW 147-150 F4.1 10-21W/m2 F(6584) ?=-9.9 [NII]6584 line flux 152-155 F4.1 10-21W/m2 e_F(6584) ?=-9.9 Error in [NII]6584 line flux 157-160 F4.1 10-21W/m2 F(6717) ?=-9.9 [SII]6717 line flux 162-165 F4.1 10-21W/m2 e_F(6717) ?=-9.9 Error in [SII]6717 line flux 167-170 F4.1 10-21W/m2 F(6730) ?=-9.9 [SII]6730 line flux 172-175 F4.1 10-21W/m2 e_F(6730) ?=-9.9 Error in [SII]6730 line flux 177-181 F5.3 --- c(Hb) ?=-9.9 Reddening constant, c(Hb) 183 A1 --- n_c(Hb) [abc] Method for the reddening constant (1)
Note (1): Method for the reddening constant as follows: a = from Hα/Hβ b = from Hγ/Hβ c = from the SED best-fitting
Byte-by-byte Description of file: tableb3.dat
Bytes Format Units Label Explanations
1- 10 I10 --- VUDS VUDS ID number 12- 16 F5.2 [Msun] logMs ?=-9.9 Logarithm of stellar mass (2) 18- 22 F5.2 [Msun] e_logMs ?=-9.9 Uncertainty in stellar mass (3) 24- 29 F6.3 [Msun/yr] logSFR ?=-9.9 Logarithm of star formation rate (4) 31- 35 F5.3 [Msun/yr] e_logSFR ?=-9.9 Uncertainty in log_SFR (5) 37- 42 F6.3 kpc re ?=-9.9 Effective radius in i-band (6) 44- 49 F6.3 kpc e_re ?=-9.9 Uncertainty in effective radius (6) 51- 56 F6.3 --- q ?=-9.9 Axis ratio in i-band (6)(7) 58- 63 F6.3 --- e_q ?=-9.9 Uncertainty in axis ratio (6) 65- 71 F7.2 Msun/pc2 sgas ?=-9.9 Gas mass surface density (8) 73- 77 F5.2 --- fgas ?=-9.9 Gas fraction (8)(9) 79- 83 F5.2 --- Ab(O) ?=-9.9 Gas-phase metallicity 12+log(O/H) (10) 85- 89 F5.2 --- e_Ab(O) ?=-9.9 Uncertainty in metallicity (10) 91- 95 F5.2 --- log(U) ?=-9.9 Ionization parameter log(U) (10) 97-101 F5.2 --- e_log(U) ?=-9.9 Uncertainty in ionization parameter (10) 103 A1 --- MType [0-6] Morphological Type (11)
Note (2): We adopted a Chabrier IMF. Note (3): They account for the statistical uncertainties in the SED fitting. Note (4): It is computed from Hα or Hβ luminosity and adopting the Kennicutt (1998ApJ...498..541K) calibration (by assuming a Chabrier et al., 2003PASP..115..763C) IMF and a theoretical ratio Hα/Hβ=2.82). Note (5): 1-sigma error, it accounts for the propagation of errors in emission line fluxes Note (6): derived applying GALFIT to F814W-band ACS-HST images. A value of -9.9 is given for those cases in which: (a) GALFIT is not applied (VVDS-02h field) or (b) GALFIT returns an error at the end of the fitting procedure Note (7): Ratio between the minor and major axis of the ellipse enclosing half of the total luminosity of the galaxy in the F814W filter Note (8): derived inverting a Kennicutt-Schmidt law (Kennicutt & Evans, 2012ARA&A..50..531K) with exponent n=1.4. From gas surface density, total gas mass in solar units was calculated as: sgas*2pi(re_)2*106. Note (9): derived from the total gas mass and total stellar mass as: fgas=Mgas/(Mgas+Ms) Note (10): derived using the code HII-CHI-mistry (Perez-Montero et al., 2014MNRAS..441.2663P) Note (11): Morphological Type as follows: 0 = Round/nucleated 1 = Tadpole/cometary 2 = Clumpy/Chain 3 = Merger/interacting 4 = Low surface brightness 5 = unresolved 6 = not available
Acknowledgements: Antonello Calabro, nillo2412(at)
(End) Patricia Vannier [CDS] 14-Feb-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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