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

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

Feb 14, 2023 125 likes •251 views

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SLIDE 1

Sakura CLAW, Mar. 28, 2018

Testing the physical origins of an Enormous Lyα Nebula at z = 2.3

by bright background galaxies

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SLIDE 2
  • extremely luminous/extended Lyα sources w

α

  • Slug
  • Luminosity (erg s-1)

Size (kpc)

MAMMOTH-1

Lya

Borisova+16

Jackpot

Hennawi+15

Enormous Lyα Nebulae (ELANe)

Slug

Cantalupo+14

・beyond viral diameter (280 pkpc) of host qso—> trace IGM filaments

LLyα > 1044 erg s−1 Size > 300 pkpc

MAMMOTH-1

Cai+17

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SLIDE 3

Physical origins

  • HI property is still unknown—> optically thin? thick?

・no strong constraints on the physical origin ①Fluorescence ②Scattering Key quantity: HI Optical depth of extended Lyα components

?

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SLIDE 4

Background sources

  • to constrain HI optical depth of extended Lyα components,

QSO Bright galaxy Rare

? ?

—> HI absorptions in background galaxy spectra

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SLIDE 5

60” (~500 pkpc)

MAMMOTH-1

Data and observations

  • ELAN: MAMMOTH-1 at z = 2.32 (Cai+17)
  • Background: star-forming galaxies (VAB=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)

background galaxy @b=100 pkpc Keck/LRIS spectroscopy (PI: Mukae)

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SLIDE 6

Analysis—Background galaxy

  • inspected with Shapley+03 template (chi-square)
  • Mean flux-regulated continuum fit with Berry+12 template (Lee+12)

NB403 width is large (±1500km/s)—> Where is the Lyα nebula??

Cosmic mean flux (Faucher-Giguère+08)

Background galaxy at z = 2.52 (VAB = 24.5)

3800 3900 4000 4100 4200 4300 4400 4500 4600 4700 4800

Observed wavelength [ ˚ A]

  • 20
  • 10

10 20 30 40 50 60

Fλ [Arbitrary]

NII CIII

NB403

4000 4020 4040 4060 4080 4100

Observed wavelength [ ˚ A]

  • 10

10 20 30

Fλ [Arbitrary]

NB403

spectra (10Å smoothed) continuum

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SLIDE 7

Lyα investigated with Palomar/CWI observations (PI: Zheng Cai)

Analysis—Lyα component

Datacube: 3800-4200Å (R~4000) Lyα nebula emission around 1-2 arcsec —> measure the wavelength range of the Lyα emission

1”-2” annulus sightline central AGN

4020 4030 4040 4050 4060 4070

Observed wavelength [ ˚ A]

−10 10 20 30

Observed counts

CWI Spectra of Lyα nebula FWHM = 550 km/s

zLya = 2.328

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SLIDE 8

4000 4020 4040 4060 4080 4100

Observed wavelength [ ˚ A]

  • 10

10 20 30

Fλ [Arbitrary]

NB403

4020 4030 4040 4050 4060 4070

Observed wavelength [ ˚ A]

−10 10 20 30

Observed counts

CWI Spectra of Lyα nebula FWHM = 550 km/s

Results—HI absorption

transmission 0.09±0.01 —> tau = 2.36+2.99-0.67 —> HI is optically thick @bright Lyα nebula components (b=100 pkpc)

4000 4020 4040 4060 4080 4100

Observed wavelength [ ˚ A]

−10 10 20 30

Fλ [Arbitrary]

NB403 Lyα (CWI)

CWI Lyα

LRIS background galaxy spectra

HI

spectra (10Å smoothed) continuum

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SLIDE 9

Discussion1—physical origins

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

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SLIDE 10

—> assume zHeII as the systemic redshift of MAMMOTH-1

Discussion2—AGN proximity

Extended HeII at the center of MAMMOTH-1 (HeII/Lyα∼0.1; Cai+17)

nnn

NB403 image

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SLIDE 11

−1500 −1000 −500 500 1000 1500

Relative Velocity [kms−1] Flux [Arbitrary]

HeII (nebula center) Lyα (nebula center) Lyα (1-2 arcsec) Lyα (1-4 arcsec)

4000 4020 4040 4060 4080 4100

Observed wavelength [ ˚ A]

−10 10 20 30

Fλ [Arbitrary]

NB403 Lyα (CWI)

—> AGN proximity: transmission 0.67±0.10 —> tau = 0.40+0.16-0.14 —> optically thin (ionized/heated by the central AGN?)

emissions of Lyα nebula Lyα (annulus) at b = 100 pkpc Lyα & HeII at the nebula center

  • ffset

4000 4020 4040 4060 4080 4100

Observed wavelength [ ˚ A]

−10 10 20 30

Fλ [Arbitrary]

NB403 HeII (center) Lyα (CWI)

spectra (10Å smoothed) continuum

LRIS background galaxy spectra

Key observation HeII emissions@bright Lyα component Bright Lyα nebula components@b=100pkpc: spatially offset to the center

Discussion2—AGN proximity

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SLIDE 12

+ IGM tomography of ELANe

K.G. Lee+14 60” (~500 pkpc)

Conclusions

MAMMOTH-1

  • We obtain deep LRIS spectra of background galaxies

whose sightlines penetrate MAMMOTH-1 (one is b=100 pkpc)

  • HI absorption analysis combining with CWI spectra indicates…
  • ptically thick gas in the bright Lyα components
  • physical origins?: fluorescence vs. scattering

—> Key observations: HeII & CIV KCWI: emissions and absorptions

?