J/ApJ/783/119 z~1 Ly{alpha} emitters. I. 135 candidates from GALEX (Wold+, 2014)
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z~1 Ly{alpha} emitters. I. The luminosity function.
    Wold I.G.B., Barger A.J., Cowie L.L.
   <Astrophys. J., 783, 119 (2014)>
   =2014ApJ...783..119W    (SIMBAD/NED BibCode)
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ADC_Keywords: Galaxies, spectra ; Photometry, ultraviolet ; Redshifts ;
              Equivalent widths ; Active gal. nuclei ; X-ray sources
Keywords: cosmology: observations - galaxies: active -
          galaxies: distances and redshifts - galaxies: evolution -
          galaxies: starburst

Abstract:
    We construct a flux-limited sample of 135 candidate z~1 Ly{alpha}
    emitters (LAEs) from Galaxy Evolution Explorer (GALEX) grism data
    using a new data cube search method. These LAEs have luminosities
    comparable to those at high redshifts and lie within a 7Gyr gap
    present in existing LAE samples. We use archival and newly obtained
    optical spectra to verify the UV redshifts of these LAEs. We use the
    combination of the GALEX UV spectra, optical spectra, and X-ray
    imaging data to estimate the active galactic nucleus (AGN) fraction
    and its dependence on Ly{alpha} luminosity. We remove the AGNs and
    compute the luminosity function (LF) from 60 z~1 LAE galaxies. We find
    that the best-fit LF implies a luminosity density increase by a factor
    of ~1.5 from z~0.3 to z~1 and ~20 from z~1 to z~2. We find a z~1
    volumetric Ly{alpha} escape fraction of 0.7%+/-0.4%.

Description:
    We construct a flux-limited sample of 135 candidate z~1 Ly{alpha}
    emitters (LAEs) from Galaxy Evolution Explorer (GALEX) grism data
    using a new data cube search method. As described in Barger et al.
    (2012ApJ...749..106B), we converted multiple GALEX NUV grism images
    into a 3D (two spatial axes and one wavelength axis) data cube. Each
    background subtracted data cube consists of thirty 20{AA} narrowband
    slices covering a wavelength range of 2030-2630{AA} and a 50'*50'
    field of view (FOV).

    Spectroscopic observations were primarily obtained with the DEep
    Imaging Multi-Object Spectrograph (DEIMOS) on Keck II in a series of
    runs in 2012-2013. The observations were made with the ZD600 line/mm
    grating blazed at 7500{AA}. This gives a resolution of ~5{AA} with a
    1'' slit and a wavelength coverage of 5300{AA}. We observed our
    southern and equatorial fields (COSMOS and CDFS) with the Robert
    Stobie Spectrograph on SALT from 2011 to 2013. The observations were
    made with the pg1300 grating with the grating angle adjusted to ensure
    spectral coverage of lines redward of [Ne V]. This gives a
    resolution of ~4{AA} with a 1.5" slit and a wavelength coverage of
    2000{AA}.

    In Tables 2-5, we list all of the LAE candidates in the Chandra Deep
    Field-South (CDFS), GROTH, NGPDWS, and COSMOS fields ordered by
    redshift.

File Summary:
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 FileName    Lrecl    Records    Explanations
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ReadMe          80          .    This file
table2.dat     136         40   *Emission line sample: Chandra Deep Field-South
                                 (CDFS)-00
table3.dat     136         41   *Emission line sample: GROTH-00
table4.dat     136         35   *Emission line sample: NGPDWS-00
table5.dat     136         19   *Emission line sample: COSMOS-00
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Note on table2.dat table3.dat table4.dat table5.dat:
 The GALEX fields are defined by the following parameters from
 Table1 in the paper:
 ----------------------------------------------------------------
 Field name   RA   (J2000)   DE        Exp.     Flux      Nc  LAE
                                       (ks)   (aW/m^2^)
 ----------------------------------------------------------------
 CDFS         03:30:40    -27:27:43    353       1.8      40   24
 GROTH        14:19:58     52:46:54    291       2.0      41   19
 NGPDWS       14:36:37     35:10:17    165       2.3      35   11
 COSMOS       10:00:29    +02:12:21    140       3.2      19    4
 ----------------------------------------------------------------
 With "Flux"=flux threshold above which each field is greater
 than 80% complete, "Nc"=number of LAE candidates, and
 "LAE"=number of confirmed LAE galaxies.
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See also:
           II/312 : GALEX-DR5 (GR5) sources from AIS and MIS (Bianchi+ 2011)
 J/MNRAS/425/2116 : Arizona CDFS Environment Survey, ACES (Cooper+, 2012)
 J/ApJ/744/110    : LAE galaxies between 2.1=<z{<=}3.1 (Ciardullo+, 2012)
 J/ApJ/736/31     : HETDEX pilot survey. II. 1.9<z<3.8 LAEs (Blanc+, 2011)
 J/ApJ/738/136    : LAEs between 0.19<z<1.25 with GALEX grism (Cowie+, 2011)
 J/ApJ/725/394    : High-redshift Ly{alpha} emitters (Hu+, 2010)
 J/ApJ/711/928    : Low-redshift Ly{alpha} galaxies from GALEX (Cowie+, 2010)
 J/ApJS/191/124   : Optical spectroscopy of ECDF-S X-ray sources
                    (Silverman+, 2010)
 J/ApJS/180/102   : AEGIS-X: Chandra deep survey (Laird+, 2009)
 J/ApJ/696/1195   : COSMOS AGN spectroscopic survey. I. (Trump+, 2009)
 J/ApJS/184/158   : Chandra COSMOS survey I. (Elvis+, 2009)
 J/ApJ/693/1713   : Spectroscopy of X-ray sources in ECDF-S (Treister+, 2009)
 J/A+A/498/13     : Lyman-{alpha} emitters from redshifts z~2-3 (Nilsson+, 2009)
 J/A+A/478/83     : GOODS-South Field VLT/FORS2 redshifts. III (Vanzella+, 2008)
 J/ApJ/680/1072   : Ly{alpha}-emitting galaxies at 0.2<z<0.35 (Deharveng+, 2008)
 J/ApJS/172/70    : zCOSMOS-bright catalog (Lilly+, 2007)
 J/ApJ/671/1227   : Ly{alpha} galaxies at z~4.5 (Dawson+, 2007)
 J/ApJ/667/79     : Ly{alpha} emission-line galaxies at z=3.1 (Gronwall+, 2007)
 J/ApJ/648/7      : Ly{alpha} emitters at z=6.5 in Subaru Deep Field
                    (Kashikawa+, 2006)
 J/PASJ/58/313    : Ly{alpha} emitters in the SUBARU Deep Field
                    (Shimasaku+, 2006)
 J/AJ/131/2373    : Extended Chandra Deep Field-South survey (Virani+, 2006)
 J/ApJS/161/21    : Extended Chandra Deep Field-South survey (Lehmer+, 2005)
 J/ApJS/161/9     : X-ray survey of the NDWFS Bootes field (Kenter+, 2005)
 J/PASJ/57/165    : Ly{alpha} emitters in the SUBARU Deep Field
                    (Taniguchi+, 2005)
 J/ApJS/155/271   : Chandra Deep Field-South: Optical spectroscopy
                    (Szokoly+, 2004)
 J/AJ/126/539     : The Chandra Deep Fields North and South (Alexander+, 2003)

Byte-by-byte Description of file: table[2345].dat
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   Bytes Format Units     Label   Explanations
--------------------------------------------------------------------------------
   1-  5  A5    ---       ---     [GALEX]
   6- 18  A13   ---       GALEX   GALEX name (HHMMSS+DDMMSS; J2000)
      20  A1    ---     f_GALEX   [i] Flag "i" on GALEX indicates LAE candidate
                                   not listed in Barger et al.
                                   (2012ApJ...749..106B)
  22- 31  F10.6 deg       RAdeg   Right Ascension in decimal degrees based on
                                   near-ultraviolet (NUV) position (J2000)
  33- 43  F11.7 deg       DEdeg   Declination in decimal degrees based on
                                   near-ultraviolet (NUV) position (J2000)
  45- 49  F5.2  mag       NUV     [21.5/25.2] GALEX/NUV AB magnitude
  51- 56  F6.2  mag       FUV     [-31.1/32.8] GALEX/FUV AB magnitude
  58- 62  F5.3  ---       zUV     [0.67/1.17] Redshift from the GALEX
                                   ultraviolet spectrum
  64- 68  F5.2  [10-7W]   LLya    [42.2/43.7]? Logarithm of the Ly{alpha}
                                   luminosity log L(Ly{alpha}) (in erg/s)
  70- 72  I3    0.1nm     EW      [6/398]? Rest-frame Ly{alpha} equivalent
                                   width EW_r_(Ly{alpha}) (in {AA})
  74- 75  I2    0.1nm   e_EW      [2/65]? The 1{sigma} error in EW
  77- 81  F5.1  [mW/m2]   logFX   [-15.4/-13.1]? Logarithm of the X-ray flux
                                   (in erg/cm^2^/s) (1)
      83  A1    ---     f_logFX   [e] Flag "e" on logFX indicates a source not
                                   detected in X-ray (2)
  85- 87  A3    ---       UType   Ultraviolet classified AGN
  89- 98  F10.6 deg       RA2deg  ? Right Ascension in decimal degrees based
                                   on optical position (J2000)
 100-110  F11.7 deg       DE2deg  ? Declination in decimal degrees based on
                                   optical position (J2000)
 112-114  F3.1  arcsec    Off     [0.1/8.2]? Offset between the optical to
                                   ultraviolet position
 116-119  A4    ---     n_zOpt    Note on zOpt (no z=no optical redshift,
                                   star, or *=optical redshift in brackets in
                                   the paper)
     121  A1    ---       ---     [(]
 122-126  F5.3  ---       zOpt    [0.35/1.17]? Optical redshift z_opt_
     127  A1    ---       ---     [)]
 129-131  A3    ---     f_zOpt    Flag on zOpt (a-n) (3)
 133-136  A4    ---       OType   Optical classification (AGN or star)
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Note (1): The X-ray fluxes are defined as below for the four fields:
       CDFS-00 = log f^a^_2-8keV_ (table 2);
      GROTH-00 = log f^a^_2-10keV_ (table 3);
     NGPDWS-00 = log f^a^_2-7keV_ (table 4);
     COSMOS-00 = log f^a^_2-10keV_ (table 5).
Note (2): e=Source not detected in X-ray hard band but detected in the soft
     0.5-2keV flux band.
Note (3): Flag defined as follows:
     a = X-ray data from Lehmer et al. 2005 (cat. J/ApJS/161/21);
     b = This paper's DEep Imaging Multi-Object Spectrograph (DEIMOS) spectra;
     c = This paper's SALT spectra;
     d = Redshifts from Cooper et al. 2012 (cat. J/MNRAS/425/2116);
     e = Treister et al. 2009 (cat. J/ApJ/693/1713 ) and Szokoly et al. 2004
         (cat. J/ApJS/155/271 ) give z=0.977;
     f = Silverman et al. 2010 (cat. J/ApJS/191/124);
     g = [alt] Alternative counterpart at 52.942825, -27.494650, 2.2, (1.191)^b^
         (R.A., Decl., Offset, z_opt_);
     h = [alt] Two untargeted counterparts ~2" from NUV position;
     i = Archival DEIMOS DEEP2 spectra (Newman et al. 2013ApJS..208....5N);
     j = [alt] Alternative counterpart at 215.05445, 52.667969, 4.4, no z
         (R.A., Decl., Offset, z_opt_);
     k = [alt] Alternative counterpart at 218.98737, 35.115852, 5.8, (1.096)^b^
         (R.A., Decl., Offset, z_opt_);
     l = [alt] Alternative counterpart at 218.79877, 35.394573, 4.0, (0.977)^b^
         (R.A., Decl., Offset, z_opt_);
     m = Archival Magellan spectra from Trump et al. 2009 (cat. J/ApJ/696/1195);
     n = Archival VLT spectra from Lilly et al. 2007 (cat. J/ApJS/172/70).
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History:
    From electronic version of the journal

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(End)                                    Sylvain Guehenneux [CDS]    03-Jun-2016