X-ray nondetection of the Lyman-alpha Emitters at z ~ 4.5

Abstract

The Lyman-alpha emitters found at z ~ 4.5 by the Large Area Lyman Alpha (LALA) survey have high equivalent widths in the Lyman-alpha line, which can be produced by either narrow-lined active galactic nuclei (AGNs) or by stellar populations with a very high proportion of young, massive stars. To investigate the AGN scenario, we obtained two deep Chandra exposures to study the X-ray nature of the Lyman-alpha emitters. The 172 ks deep Chandra image on the LALA Bootes field was presented in a previous paper (Malhotra et al. 2003), and in this paper we present a new Chandra deep exposure (174 ks) on the LALA Cetus field, which doubled our sample of X-ray imaged Lyman-alpha sources, and imaged the brightest source among our Lyman-alpha emitters. None of the 101 Lyman-alpha sources covered by two Chandra exposures was detected individually in X-ray, with a 3 sigma limiting X-ray flux of F_{0.5-10.0 keV} < 3.3 x 10^{-16} ergs/cm^2/s for on-axis targets. The sources remain undetectable in the stacked image, implying a 3 sigma limit to the average luminosity of L_{2-8keV} < 2.8 x 10^{42} ergs/s. The resulting X-ray to Lyman-alpha ratio is > 21 times lower than the ratios for known high redshift type-II quasars. Together with optical spectra obtained at Keck, we conclude that no evidence of AGN activity was found among our Lyman-alpha emitters at z ~ 4.5.

arXiv comment12 pages, including 4 figures, ApJ letter accepted

References in corpus (27)

• A Wavelet-Based Algorithm for the Spatial Analysis of Poisson Data
• High-z Lyman-alpha Emitters. I. A Blank-Field Search for Objects Near Redshift z=3.4 in and around the Hubble Deep Field and the Hawaii Deep Field SSA22
• The Density of Lyman-alpha Emitters at Very High Redshift
• Large Equivalent width Lyman-alpha line emission at z=4.5: young galaxies in a young universe
• A Redshift z = 6.56 Galaxy Behind the Cluster Abell 370
• First Results from the Large Area Lyman Alpha Survey
• Subaru Deep Survey II. Luminosity Functions and Clustering Properties of Lya Emitters at z=4.86 in the Subaru Deep Field
• The HELLAS2XMM survey: IV. Optical identifications and the evolution of the accretion luminosity in the Universe
• A Classic Type 2 QSO
• The Luminosity Function of Lyman Alpha Emitters at Redshift z~5.7
• XMM-Newton observation of the Lockman Hole II. Spectral analysis
• Spectroscopic Confirmation of Three Redshift 5.7 Lyman-alpha Emitters from the Large Area Lyman Alpha Survey
• The Discovery of Two Lyman$\alpha$ Emitters Beyond Redshift 6 in the Subaru Deep Field
• Discovery of 9 Ly alpha emitters at redshift z~3.1 using narrow-band imaging and VLT spectroscopy
• Chandra Detection of a TypeII Quasar at z=3.288
• The Population of Faint Optically-Selected AGN at z~3
• Lyman Alpha Emitters at Redshift z=5.7
• Subaru Deep Survey. IV. Discovery of a Large-Scale Structure at Redshift \simeq 5
• Probing the faint end of the Galaxy luminosity function at z=3 with Ly-alpha emission
• Red Galaxy Clustering in the NOAO Deep Wide-Field Survey
• A Search for Lyman alpha Emitters at Redshift 3.7
• No X-ray Bright Type II Quasars Among the Lyman-alpha Emitters
• Optical and Near-Infrared Spectroscopy of a High-Redshift, Hard X-ray Emitting Spiral Galaxy
• Lyman alpha emitters with red colors at z~=2.4
• 172 ks Chandra Exposure of the LALA Boötes Field: X-ray Source Catalog
• Multi-wavelength observations of serendipitous Chandra X-ray sources in the field of A2390
• A Hard Medium Survey with ASCA. IV: the Radio-Loud Type 2 QSO AXJ0843+294 2

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