A Luminosity Function of Lyman Alpha Emitting Galaxies at Redshift 4.5

Abstract

We present a catalog of 59 z=4.5 Lyman alpha emitting galaxies spectroscopically confirmed in a campaign of Keck/DEIMOS follow-up observations to candidates selected in the Large Area Lyman Alpha (LALA) narrow-band imaging survey. We targeted 97 candidates for spectroscopic follow-up; by accounting for the variety of conditions under which we performed spectroscopy, we estimate a selection reliability of about 76%. Together with our previous sample of Keck/LRIS confirmations, the 59 sources confirmed herein bring the total catalog to 73 spectroscopically confirmed z=4.5 Lyman alpha emitting galaxies in the 0.7 square degrees covered by the LALA imaging. As with the Keck/LRIS sample, we find that a non-negligible fraction of the confirmed Lyman alpha lines have rest-frame equivalent widths (w_{rest}) which exceed the maximum predicted for normal stellar populations: 17% -- 31% (93% confidence) of the detected galaxies show w_{rest} > 190 AA, and 12% -- 27% (90% confidence) show w_{rest} > 240 AA. We construct a luminosity function of z=4.5 Lyman alpha emission lines for comparison to Lyman alpha luminosity functions spanning 3.1 < z < 6.6. We find no significant evidence for Lyman alpha luminosity function evolution from z ~ 3 to z ~ 6. This result supports the conclusion that the intergalactic medium remains largely reionized from the local universe out to z=6.5. It is somewhat at odds with the pronounced drop in the cosmic star formation rate density recently measured between z~3 and z~6 in continuum-selected Lyman-break galaxies, and therefore potentially sheds light on the relationship between the two populations.

36 pages, 10 figures; resubmitted to The Astrophysical Journal (after one round of referee's comments)

References in corpus (5)

• The Hubble Ultra Deep Field
• Subaru Deep Survey V. A Census of Lyman Break Galaxies at z=4 and 5 in the Subaru Deep Fields: Photometric Properties
• Ly-alpha Emission-Line Galaxies at z = 3.1 in the Extended Chandra Deep Field South
• Luminosity Functions of Lyman Alpha Emitting Galaxies and Cosmic Reionization of Hydrogen
• Clustering of Lyman alpha emitters at z ~ 4.5

Cited by in corpus (11)

• Effects of Dust Geometry in Lyman Alpha Galaxies at z = 4.4
• Lyman-alpha Emitters During the Early Stages of Reionization
• Lyman alpha emitting galaxies at 0.2 < z < 0.35 from GALEX spectroscopy
• Lyman-alpha Damping Wing Constraints on Inhomogeneous Reionization
• Signatures of reionization on Lyman alpha emitters
• Serendipitous Discovery of an Overdensity of Lyman-Alpha Emitters at z~4.8 in the Cl1604 Supercluster Field
• Ly-alpha emitting galaxies at redshift z~4.5 in the LALA Cetus field
• A Magellan IMACS Spectroscopic Search for Lyman-Alpha Emitting Galaxies at Redshift 5.7
• Interpreting the Transmission Windows of Distant Quasars
• The DEEP2 Redshift Survey: Lyman Alpha Emitters in the Spectroscopic Database
• The Expected Detection of Dust Emission from High-Redshift Lyman Alpha Galaxies