Properties of Lyα emitters around the radio galaxy MRC 0316 257

By B. Venemans, H. Röttgering, G. Miley, J. Kurk, C. De Breuck, R. Overzier, W. Breugel, C. Carilli, H. C. Ford, T. Heckman and 2 more. 2005

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Observations of the radio galaxy MRC 0316–257 at $z = 3.13$ and the surrounding field are presented. Using narrow- and broad-band imaging obtained with the VLT, 77 candidate Ly α emitters with a rest-frame equivalent width of >15 A were selected in a ∼ 7´$\,\times\,7$´ field around the radio galaxy. Spectroscopy of 40 candidate emitters resulted in the discovery of 33 emission line galaxies of which 31 are Ly α emitters with redshifts similar to that of the radio galaxy, while the remaining two galaxies turned out to be [$\ion{O}{ii}$] emitters. The Ly α profiles have widths ( FWHM ) in the range of 120–800 km s -1 , with a median of 260 km s -1 . Where the signal-to-noise was large enough, the Ly α profiles were found to be asymmetric, with apparent absorption troughs blueward of the profile peaks, indicative of absorption along the line of sight of an $\ion{H}{i}$ mass of at least $2 \times 10^2 {-} 5 \times 10^4$ M $_{\odot}$. Besides that of the radio galaxy and one of the emitters that is a QSO, the continuum of the emitters is faint, with luminosities ranging from 1.3 L * to L * . The colors of the confirmed emitters are, on average, very blue. The median UV continuum slope is $\beta = -1.76$, bluer than the average slope of LBGs with Ly α emission ($\beta \sim -1.09$). A large fraction of the confirmed emitters ( ∼ 2/3) have colors consistent with that of dust-free starburst galaxies. Observations with the Advanced Camera for Surveys on the Hubble Space Telescope show that the emitters that were detected in the ACS image have a range of different morphologies. Four Ly α emitters ( ∼ 25%) were unresolved with upper limits on their half light radii of $r_{\rm h} ∼ 19%) show multiple clumps of emission, as does the radio galaxy, and the rest ( ∼ 56%) are single, resolved objects with $r_{\rm h} α emitters are on average smaller than LBGs. The average star formation rate of the Ly α emitters is 2.6 M $_{\odot}\;{\rm yr}^{-1}$ as measured by the Ly α emission line or M $_{\odot}\;{\rm yr}^{-1}$ as measured by the UV continuum. The properties of the Ly α galaxies (faint, blue and small) are consistent with young star forming galaxies which are still nearly dust free. The volume density of Ly α emitting galaxies in the field around MRC 0316–257 is a factor of $3.3^{+0.5}_{-0.4}$ larger compared with the density of field Ly α emitters at that redshift. The velocity distribution of the spectroscopically confirmed emitters has a dispersion of 640 km s -1 , corresponding to a FWHM of 1510 km s -1 , which is substantially smaller than the width of the narrow-band filter (${\it FWHM} \sim 3500$ km s -1 ). The peak of the velocity distribution is located within 200 km s -1 of the redshift of the radio galaxy. We conclude that the confirmed Ly α emitters are members of a protocluster of galaxies at $z \sim 3.13$. The size of the protocluster is unconstrained and is larger than $3.3 \times 3.3$ Mpc 2 . The mass of this structure is estimated to be >$3{-}6 \times 10^{14}$ M $_{\odot}$ and could be the progenitor of a cluster of galaxies similar to e.g. the Virgo cluster.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/948745858c4bfeafc7f4a0cd7f76530fea397416

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Citations in the corpus

Distant radio galaxies and their environments (2008, methodology): “The measured overdensities of Lyα emitters in the radio-selected protoclusters are factors of 3 - 5 larger than the field density of Lyα emitters at similar redshifts (Venemans et al 2005, 2007).”
Galaxy Zoo Green Peas: discovery of a class of compact extremely star-forming galaxies (2009, background): “UV-luminous high redshift galaxies, like Ly-α emitters and Lyman-break galaxies, are characterized by a high UV luminosity and a relatively low obscuration by dust (Gawiser et al. 2006; Venemans et al. 2005).”
Lyα Emission-Line Galaxies at z = 3.1 in the Extended Chandra Deep Field-South (2007, methodology): “…been successfully conducted at a number of redshifts, including z 2:4 (Stiavelli et al. 2001), z 3:1 (Ciardullo et al. 2002; Hayashino et al. 2004; Venemans et al. 2005; Gawiser et al. 2006a), z 3:7 (Fujita et al. 2003), z 4:5 (Rhoads et al. 2000), z 4:9 (Ouchi et al. 2003), z 5:7 (Rhoads et al.…”
Clusters of Galaxies in the First Half of the Universe from the IRAC Shallow Survey (2008, background): “Searches for clusters around radio galaxies have yielded protoclusters with redshifts as high as 4.1 (Pentericci et al. 2000; Venemans et al. 2002, 2005) and possibly even 5.2 (Overzier et al. 2006).”
The realm of the galaxy protoclusters (2016, methodology): “…of previously known radio galaxies (e.g., Pascarelle et al., 1996; Le Fevre et al., 1996; Pentericci et al., 2000; Kurk et al., 2000, 2004a; Venemans et al., 2002, 2004, 2005, 2007; Chiaberge et al., 2010; Kuiper et al., 2011; Hatch et al., 2011a,b; Mawatari et al., 2012; Hayashi et al.,…”
The first appearance of the red sequence of galaxies in proto-clusters at 2 <~ z <~ 3 (2007, background): “…we discuss later, these proto-clusters already seem to contain an evolved galaxy population as well as young Lyα/Hα emitters (Kurk et al. 2004a; 2004b; Venemans et al. 2007) which tend to be much less massive, typically by more than an order of magnitude (Gawiser et al. 2006; Venemans et al. 2005).”
Lyα-EMITTING GALAXIES AT z = 2.1 IN ECDF-S: BUILDING BLOCKS OF TYPICAL PRESENT-DAY GALAXIES? (2009, background): “We assume that inside the B broad-band filter only the continuum is observed: fν,B = ∫ fν,c(λ)(c/λ 2)TB(λ)dλ∫ (c/λ2)TB(λ)dλ = ∫ e−τeff (λ)Cν(c/λ 2)TB(λ)dλ∫ (c/λ2)TB(λ)dλ = QBCν , (A5) where QB is defined as: ∫ e −τeff (λ)(c/λ2)TB(λ)dλ∫ (c/λ2)TB(λ)dλ = 0.999 ∼ 1, but U is just like NB3727 with emissi”
3D Lyman-alpha radiation transfer. I. Understanding Lyman-alpha line profile morphologies (2006, background): “…P-Cygni profiles, double peak profiles, pure (symmetric) emission line profiles, and combinations thereof (see e.g. Kunth et al. 1998, MasHesse et al. 2003, Shapley et al. 2003, Möller et al. 2004, Venemans et al. 2005, Wilman et al. 2005, Noll et al. 2004, Tapken et al. 2004, Tapken 2005).”