A Flux-Limited Sample of z~1 Ly-alpha Emitting Galaxies in the CDFS

Abstract

We describe a method for obtaining a flux-limited sample of Ly-alpha emitters from GALEX grism data. We show that the multiple GALEX grism images can be converted into a three-dimensional (two spatial axes and one wavelength axis) data cube. The wavelength slices may then be treated as narrowband images and searched for emission-line galaxies. For the GALEX NUV grism data, the method provides a Ly-alpha flux-limited sample over the redshift range z=0.67-1.16. We test the method on the Chandra Deep Field South field, where we find 28 Ly-alpha emitters with faint continuum magnitudes (NUV>22) that are not present in the GALEX pipeline sample. We measure the completeness by adding artificial emitters and measuring the fraction recovered. We find that we have an 80% completeness above a Ly-alpha flux of 10^-15 erg/cm^2/s. We use the UV spectra and the available X-ray data and optical spectra to estimate the fraction of active galactic nuclei in the selection. We report the first detection of a giant Ly-alpha blob at z<1, though we find that these objects are much less common at z=1 than at z=3. Finally, we compute limits on the z~1 Ly-alpha luminosity function and confirm that there is a dramatic evolution in the luminosity function over the redshift range z=0-1.

18 pages, in press at The Astrophysical Journal

References in corpus (8)

• Ly-alpha Emission-Line Galaxies at z = 3.1 in the Extended Chandra Deep Field South
• The Great Observatories Origins Deep Survey. VLT/VIMOS Spectroscopy in the GOODS-South Field
• MegaPipe: the MegaCam image stacking pipeline at the Canadian Astronomical Data Centre
• Deep U band and R imaging of GOODS-South: Observations,data reduction and first results
• Lyman alpha emitting galaxies at 0.2 < z < 0.35 from GALEX spectroscopy
• Evolution of Lyman Alpha Galaxies: Stellar Populations at z ~ 0.3
• Emission-Line Galaxies from the PEARS Hubble Ultra Deep Field: A 2-D Detection Method and First Results
• A Plethora of AGN Among Lyman Alpha Galaxies at Low Redshift

Cited by in corpus (24)

• Bright and Faint Ends of Ly$\alpha$ Luminosity Functions at $\text{z}=2$ Determined by the Subaru Survey: Implications for AGN, Magnification Bias, and ISM HI Evolution
• The CALYMHA survey: Lya luminosity function and global escape fraction of Lya photons at z=2.23
• Lyman alpha Emitting Galaxies in the Nearby Universe
• Morphologies of ~190,000 Galaxies at z=0-10 Revealed with HST Legacy Data. III. Continuum Profile and Size Evolution of Lya Emitters
• Searching for Neutral Hydrogen Halos around z ~ 2.1 and z ~ 3.1 Ly-alpha Emitting Galaxies
• Cross-correlating Carbon Monoxide Line-intensity Maps with Spectroscopic and Photometric Galaxy Surveys
• z~1 Lya Emitters I. The Luminosity Function
• Deciphering Lyman $\alpha$ blob 1 with deep MUSE observations
• Lyman alpha Luminosity Functions at Redshift z = 4.5
• A Faint Flux-Limited Lyman Alpha Emitter Sample at $z\sim 0.3$
• Empirical Constraints on the Star Formation & Redshift Dependence of the Lyman Alpha `Effective' Escape Fraction
• Lyman Alpha and MgII as Probes of Galaxies and their Environments
• About AGN ionization echoes, thermal echoes, and ionization deficits in low redshift Lyman-alpha blobs
• LINEAR: A Novel Algorithm for Reconstructing Slitless Spectroscopy from HST/WFC3
• The Origin and Evolution of Lyman-alpha Blobs in Cosmological Galaxy Formation Simulations
• The average submillimetre properties of Lyman-alpha Blobs at z=3
• A high dust emissivity index beta for a CO-faint galaxy in a filamentary Lyman-alpha nebula at z=3.1
• A $1.4$ deg${}^2$ blind survey for CII], CIII] and CIV at $\mathbf{z}\sim 0.7-1.5$. II: luminosity functions and cosmic average line ratios
• NuSTAR hard X-ray data and Gemini 3D spectra reveal powerful AGN and outflow histories in two low-redshift Lyman-$\alpha$ blobs
• Observations of Ly$\alpha$ Emitters at High Redshift
• Properties of the Lowest Metallicity Galaxies Over the Redshift Range z = 0.2 to z = 1
• Modelling the Evolution of Ly$\alpha$ Blobs and Ly$\alpha$ Emitters
• Direct correlation of line intensity mapping and CMB lensing from evolution along the lightcone
• A Correction for GALEX Spectroscopic UV Flux Distributions from Comparisons with CALSPEC and IUE