Lyman-α Emitters are different from other high-z Galaxies

Lyman-α Emitters are different from other high-z Galaxies Johan Fynbo, Dark Cosmology Centre, Niels Bohr Institute

Galaxies at z=3: TLAs • LAE=Lyman Alpha Emitter (=LYE? =LEGO?) selected via strong emission line (contains young massive stars & gas) • LBG=Lyman Break Galaxy selected via Lyman break, blue continuum (starforming) • DRG=Distant Red Galaxy selected via Balmer break in observed NIR • SMG=Sub-Millimeter detected Galaxy hyperluminous in sub-mm, implying huge SFR, 30K colddust • DLA=Damped Lyman-Absorption system selected in HI absorption, N(HI)>2×1020cm-2 • GHG=GRB (Gamma-Ray Burst) Host Galaxy Burst rate is some function of SFR • AGN=Active Galactic Nucleus selected in X-rays, mid-infrared or via LBG-like colors

Distant red galaxies GRB hosts Damped Lyman-aAbsorbers Lyman-break galaxies SMGs Lyman-agalaxies

Lyman-α Emitters and LBGs Central papers: Steidel et al. 2000: LyαImaging of a Proto-Cluster Region at <z>=3.09 Shapley et al. 2001: The Rest-Frame Optical Properties of z~=3 Galaxies Shapley et al. 2003: Rest-Frame Ultraviolet Spectra of z~3 Lyman Break Galaxies See also posters by Ohta & Yuma for z=5 results

Origin of the Lyman break Steidel & Hamilton 1992

Lyα emitters 25% EW>20Å

25% lower limit? Lyman-α more extended than continuum emission larger slit-loss for Lyman-α flux (Møller & Warren 1998; also Veneman’s talk) LEGO2138_29, Fynbo et al. 2003

25% lower limit? Offset between Lyα and continuum emission. Again, also Veneman’s talk.  Lyman-α flux lost and velocity shifts between Lyman-α and Continuum. S9 from Q1205-30 field, Fynbo et al. 2001

Are Lyman- emitting LBGs the most dust poor among LBGs? (25%) Cf. also Veneman’s And MUSYC talks. Adelberger & Steidel (2000)

Are Lyman- emitting LBGs the youngest or the oldest among LBGs? Shapley et al. (2001, Sect. 6-7) Young: t<35Myr <E(B-V)>=0.26 Old: t>1Gyr <E(B-V)>=0.10 (25%) LBGswith Lyman-αmainly from old population? Ages meaningless? Guaita+Nilsson+: Two populations of Lyman-α emitters? Adelberger & Steidel (2000)

Shapley: Rather velocity width effect than a metallicity effect? Fainter LBGs with Lyman-α emission have larger EWs.

Lyman-alpha emitters are fainter. Rather, • LBGs with R<25.5 are the tip of the iceberg. N B R

Damped Lyman-α Absorbers z=2.81 Møller & Warren 1993, see also Wolfe, Gawiser & Prochaska 2005

Damped Lyman-α Absorbers Djorgovski et al. 1996

Damped Lyman-α Absorbers HST / STIS VLT Q2206-199, z(DLA)=1.92 VLT PKS0458-02, z(DLA)=2.04 10 null detections per detection Møller et al. 2002, 2004

The faint(est?) Lyα Emitters = DLAs? Rauch et al. 2008, see also Barnes & Haehnelt 2008

GRB Host Galaxies z=3.42 z≈3.5 z=2.04 z=2.04 Paul Vreeswijk (PhD thesis), Fruchter et al. 2006

GRB hosts are sometimes Lyman- emitters LyaEmission Fynbo et al. (A&A, 2002) ≈Solar metallicity Fynbo et al. (A&A, 2001) Far from always Lyman-α from GRB hosts! (Milvang-Jensen later today)

SMGs and DRGs are sometimes Lyα emitters, but far from always Van Dokkum et al. (2003), Chapman et al. (2005)

Complex spectra of z=2 Lyman-α emitters (Møller et al.) CII*? CIV HeII NV

Lyα Emitters SMGs DRGs GRB hosts LBGs DLAs

Reality? LBGs • (to R=∞) Lyα Emitters SMGs DLAs SteidelLBGs DRGs GRB hosts All high-z galaxies

Conclusions • There is substantial overlap between Lyman-α emitters and basically all other known high-z “populations”, but never 1-1. • Not sure which parameters regulate thestrength of Lyman-α(age, Z, E(B-V),q, kinematics, mass, geometry – all correlated to some extent). • Need more robust derivations of the above parameters to establish where Lyman-α emitters belong in the big picture. • More spectroscopy of Lyman-α emitters covering a wider wavelength range would be desirable. Contaminating emission line sources can be other than OII • MUSYC is a very nice enterprise.

CIV HeII CIII Milvang-Jensen

Lyman-α Emitters are different from other high-z Galaxies