Testing the physical origins of an Enormous Ly Nebula at z = 2.3 by - PowerPoint PPT Presentation

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������������ Enormous Ly α Nebulae (ELANe) α MAMMOTH-1 Slug MAMMOTH-1 Size (kpc) Slug ������� Cai+17 Jackpot Cantalupo+14 Borisova+16 Lya Luminosity (erg s -1 ) Hennawi+15 L Ly α > 10 44 erg s − 1 • extremely luminous/extended Ly α sources w Size > 300 pkpc ・ beyond viral diameter (280 pkpc) of host qso—> trace IGM filaments

Physical origins ① Fluorescence ② Scattering ? ・ no strong constraints on the physical origin • HI property is still unknown—> optically thin? thick? Key quantity: HI Optical depth of extended Ly α components

Background sources ? ? Bright galaxy QSO Rare • to constrain HI optical depth of extended Ly α components, —> HI absorptions in background galaxy spectra

Data and observations • ELAN : MAMMOTH-1 at z = 2.32 (Cai+17) • Background : star-forming galaxies ( V AB =23.8-24.6) at z=2.4-2.8 • BX selection (Steidel+04) + Photo-z (EAZY; Brammer+08) <— imaging data: LBT/LBC (U,V, i) & UKIRT/WFCAM (J, H) MAMMOTH-1 Keck/LRIS spectroscopy (PI: Mukae) 60” (~500 pkpc) background galaxy @b=100 pkpc

Analysis—Background galaxy Background galaxy at z = 2.52 ( V AB = 24.5) inspected with Shapley+03 template (chi-square) • Mean flux-regulated continuum fit with Berry+12 template (Lee+12) • 30 60 NB403 NB403 NII CIII 50 20 40 F λ [Arbitrary] F λ [Arbitrary] 30 continuum 10 20 10 0 0 -10 spectra Cosmic mean flux -10 (10 Å smoothed) (Faucher-Giguère+08) -20 3800 3900 4000 4100 4200 4300 4400 4500 4600 4700 4800 Observed wavelength [ ˚ 4000 4020 4040 4060 4080 4100 A] Observed wavelength [ ˚ A] NB403 width is large (±1500km/s)—> Where is the Ly α nebula??

Analysis—Ly α component Ly α investigated with Palomar/CWI observations (PI: Zheng Cai) CWI Spectra of Ly α nebula 30 z Lya = 2.328 1”-2” annulus 20 Observed counts sightline 10 central AGN 0 FWHM = 550 km/s − 10 4020 4030 4040 4050 4060 4070 Observed wavelength [ ˚ A] Datacube: 3800-4200 Å (R~4000) Ly α nebula emission around 1-2 arcsec —> measure the wavelength range of the Ly α emission

Results—HI absorption LRIS background galaxy spectra 30 30 CWI Spectra of Ly α nebula NB403 NB403 Ly α (CWI) 30 20 CWI Ly α 20 HI 20 F λ [Arbitrary] F λ [Arbitrary] Observed counts continuum 10 10 10 0 0 0 spectra FWHM = 550 km/s − 10 -10 − 10 4020 4030 4040 4050 4060 4070 (10 Å smoothed) Observed wavelength [ ˚ A] 4000 4000 4020 4020 4040 4040 4060 4060 4080 4080 4100 4100 Observed wavelength [ ˚ Observed wavelength [ ˚ A] A] transmission 0.09±0.01 —> tau = 2.36 +2.99-0.67 —> HI is optically thick @bright Ly α nebula components (b=100 pkpc)

Discussion1—physical origins The optical depth indicates that the HI gas is optically thick cloud whose ionized(neuetral) skin contributes to Fluorescence(Scattering) ① Optically thick Fluorescence ② Scattering Key observation HeII & CIV emissions@bright Ly α nebula component

Discussion2—AGN proximity NB403 image nnn Extended HeII at the center of MAMMOTH-1 (HeII/Ly α ∼ 0.1; Cai+17) —> assume z HeII as the systemic redshift of MAMMOTH-1

Discussion2—AGN proximity LRIS background galaxy spectra emissions of Ly α nebula 30 30 NB403 HeII (nebula center) NB403 Ly α (nebula center) Ly α (CWI) HeII (center) Ly α (1-2 arcsec) offset Ly α (CWI) Ly α (1-4 arcsec) 20 20 Flux [Arbitrary] F λ [Arbitrary] F λ [Arbitrary] continuum 10 10 0 0 spectra − 1500 − 1000 − 500 0 500 1000 1500 − 10 − 10 Relative Velocity [kms − 1 ] (10 Å smoothed) 4000 4020 4040 4060 4080 4100 Ly α & HeII Ly α (annulus) 4000 4020 4040 4060 4080 4100 Observed wavelength [ ˚ Observed wavelength [ ˚ A] A] at the nebula center at b = 100 pkpc B right Ly α nebula components@b=100pkpc : spatially offset to the center —> AGN proximity: transmission 0.67±0.10 —> tau = 0.40 +0.16-0.14 —> optically thin (ionized/heated by the central AGN?) Key observation HeII emissions@bright Ly α component

������������ Conclusions • We obtain deep LRIS spectra of background galaxies MAMMOTH-1 whose sightlines penetrate MAMMOTH-1 (one is b=100 pkpc) • HI absorption analysis combining with CWI spectra indicates… optically thick gas in the bright Ly α components • physical origins?: fluorescence vs. scattering —> Key observations: HeII & CIV KCWI: emissions and absorptions 60” (~500 pkpc) + IGM tomography of ELANe K.G. Lee+14 ?