Spectroscopic Properties of the z4.5 LyaEmitters

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Spectroscopic Properties of the z4.5 Lya-Emitters
Steve Dawson (UCB) in collaboration
with Arjun Dey (NOAO) Buell Jannuzi
(NOAO) Sangeeta Malhotra (STSci) James Rhoads
(STSci) Hyron Spinrad (UCB) Daniel Stern (JPL)
Keck/DEIMOS (Dawson et al. 2004b)
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Ensemble Results EW Distribution
Max. Lya EW predicted for normal stellar pop.
(Charlot Fall 1993)
20 - 35 of the Lya-emitters in the
spectroscopic sample show EW gt 240 A. Normal
star formation is not powering these sources.
What is?
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AGN Among the z 4.5 Population?
Lack of detectable X-ray emission (LX lt 1042 erg
s-1) in deep Chandra ACIS imaging implies no.
(Wang et al. 2004)
Lack of high-ionization state emission lines in
spectra of restframe UV implies no.
f(HeII) lt 0.13 f(Lya) (2s)
f(CIV) lt 0.08 f(Lya) (2s)
No detectable CIV l1549 emission
No detectable HeII l1640 emission