Surface Brightness Profile of Lyman-alpha Halos out to 320 kpc in HETDEX

Lujan Niemeyer, Maja; Komatsu, Eiichiro; Byrohl, Chris; Davis, Dustin; Fabricius, Maximilian; Gebhardt, Karl; Hill, Gary J.; Wisotzki, Lutz; Bowman, William P.; Ciardullo, Robin; Farrow, Daniel J.; Finkelstein, Steven L.; Gawiser, Eric; Gronwall, Caryl; Jeong, Donghui; Landriau, Martin; Liu, Chenxu; Cooper, Erin Mentuch; Ouchi, Masami; Schneider, Donald P. und Zeimann, Gregory R. (2022): Surface Brightness Profile of Lyman-alpha Halos out to 320 kpc in HETDEX. In: Astrophysical Journal, Bd. 929, Nr. 1, 90

Abstract

We present the median-stacked Lyman-alpha (Ly alpha) surface brightness profiles of 968 spectroscopically selected Ly alpha emitting galaxies (LAEs) at redshifts 1.9 < z < 3.5 in the early data of the Hobby-Eberly Telescope Dark Energy Experiment. The selected LAEs are high-confidence Ly alpha detections with high signal-to-noise ratios observed with good seeing conditions (voint-spread function FWHM <1.'' 4), excluding active galactic nuclei. The Ly alpha luminosities of the LAEs are 10(42.4)-10(43) erg s(-1). We detect faint emission in the median-stacked radial profiles at the level of (3.6 +/- 1.3) x 10(-20) erg s(-1) cm(-2) arcsec(-2) from the surrounding Ly alpha halos out to r similar or equal to 160 kpc (physical). The shape of the median-stacked radial profile is consistent at r < 80 kpc with that of much fainter LAEs at 3 < z < 4 observed with the Multi Unit Spectroscopic Explorer (MUSE), indicating that the median-stacked Ly alpha profiles have similar shapes at redshifts 2 < z < 4 and across a factor of 10 in Ly alpha luminosity. While we agree with the results from the MUSE sample at r < 80 kpc, we extend the profile over a factor of two in radius. At r > 80 kpc, our profile is flatter than the MUSE model. The measured profile agrees at most radii with that of galaxies in the Byrohl et al. cosmological radiative transfer simulation at z = 3. This suggests that the surface brightness of a Ly alpha halo at r < 100 kpc is dominated by resonant scattering of Ly alpha photons from star-forming regions in the central galaxy, whereas at r > 100 kpc, it is dominated by photons from galaxies in surrounding dark matter halos.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 0004-637X
• Sprache: Englisch
• DFG: Gefördert durch die Deutsche Forschungsgemeinschaft (DFG) - 390783311