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J/MNRAS/458/3443 Cl0939+4713 Hα z∼0.4 star-forming galaxies (Sobral+ 2016)

The nature of Hα star-forming galaxies at z ∼ 0.4 in and around Cl 0939+4713: the environment matters. Sobral D., Stroe A., Koyama Y., Darvish B., Calhau J., Afonso A., Kodama T., Nakata F. <Mon. Not. R. Astron. Soc., 458, 3443-3454 (2016)> =2016MNRAS.458.3443S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Redshifts ; Spectroscopy Keywords: galaxies: clusters: general - galaxies: evolution - intergalactic medium - cosmology: observations - large-scale structure of Universe Abstract: Cluster star-forming galaxies are found to have an excess of far-infrared emission relative to Hα, when compared to those in the field, which could be caused by intense active galactic nuclei (AGN) activity, dust and/or declining star formation histories. Here we present spectroscopic observations of Hα emitters in the Cl 0939+4713 (Abell 851) super-cluster at z=0.41, using AF2+ WYFFOS on the William Herschel Telescope. We measure [OII], Hβ, [OIII], Hα and [NII] for a sample of 119 Hα emitters in and around the cluster. We find that 17±5 per cent of the Hα emitters are AGN, irrespective of environment. For star-forming galaxies, we obtain Balmer decrements, metallicities and ionization parameters with different methods, individually and by stacking. We find a strong mass-metallicity relation at all environments, with no significant dependence on environment. The ionization parameter declines with increasing stellar mass for low-mass galaxies. Hα emitters residing in intermediate environments show the highest ionization parameters (along with high [OIII]/Hα and high [OIII]/[OII] line ratios, typically twice as large as in the highest and lowest densities), which decline with increasing environmental density. Dust extinction (A) correlates strongly with stellar mass, but also with environmental density. Star-forming galaxies in the densest environments are found to be significantly dustier (A~=1.5-1.6) than those residing in the lowest density environments (A~=0.6), deviating significantly from what would be predicted given their stellar masses. Description: We followed up 214 candidate Hα line emitters from Koyama et al. (2011ApJ...734...66K) using AF2 on the WHT in La Palma (program ID: W14BN020) on the second half of four nights during 2015 January 22-25. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 152 119 Hα emitters in our spectroscopic sample with Flags 1,2,3
See also: J/MNRAS/416/2041 : Hα emitters at z=2.23 (Matsuda+, 2011) J/ApJ/765/26 : Very low-z SDSS galaxies with Hα emission (Shim+ 2013) Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 8 A8 --- ID Name (DUSQ_NNN) 10- 11 I2 h RAh Right ascension (J2000) 13- 14 I2 min RAm Right ascension (J2000) 16- 21 F6.3 s RAs Right ascension (J2000) 23 A1 --- DE- Declination sign (J2000) 24- 25 I2 deg DEd Declination (J2000) 27- 28 I2 arcmin DEm Declination (J2000) 30- 34 F5.2 arcsec DEs Declination (J2000) 36- 43 F8.6 --- zsp Spectroscopic redshift 45- 52 F8.6 --- e_zsp rms uncertainty on zsp 54- 59 F6.3 mag zmag SDSS z' magnitude 61- 68 F8.4 [mW/m2] logF(Ha) Flux in Hα 70- 74 F5.3 [Mpc-2] logSigma10 Local environmental density 76- 83 F8.6 --- [NII]/Ha ?=- [NII]6584/Hα line flux ratio 85- 92 F8.6 --- [OIII]/Hb ?=- [OIII]5007/Hβ line flux ratio 94-101 F8.6 --- [OIII]/Ha ?=- [OIII]5007/Hα line flux ratio 103-110 F8.6 --- [OII]/Ha ?=- [OII]3727/Hα line flux ratio 112-119 F8.5 [Msun] logM* Stellar mass 121 I1 --- Flag [1/3] Flag (1) 123-125 I3 --- AGN [-1/2]?=-99 AGN flag (2) 127 I1 --- Point [1/4] Pointing identification number 129-133 F5.3 mag B-I B-I colour index 135-142 F8.4 0.1nm EWrest Rest-frame Hα+[NII] equivalent width 144-152 F9.6 arcmin Rc Radius used to calculate logSigma10
Note (1): Flag as follows: 1 = Hα and at least two other emission lines 2 = Hα and at least another emission line detected at S/N>5 3 = at least one emission line detected at S/N>5 4 = a potential Hα line but at too low S/N (S/N<5) Note (2): AGN flag as follows: -1 = Unclass 0 = SFGs 1 = Others 2 = AGN
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 01-Jun-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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