Podcast
Questions and Answers
What is the estimated age of the galaxy JWST-ER1g?
What is the estimated age of the galaxy JWST-ER1g?
What is the approximate stellar mass of JWST-ER1g?
What is the approximate stellar mass of JWST-ER1g?
What is the effective radius of JWST-ER1g?
What is the effective radius of JWST-ER1g?
What is the dark matter mass within the Einstein radius?
What is the dark matter mass within the Einstein radius?
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What is the star formation rate of JWST-ER1g?
What is the star formation rate of JWST-ER1g?
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Why is JWST-ER1g not a quiescent galaxy?
Why is JWST-ER1g not a quiescent galaxy?
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What is the shape of JWST-ER1g?
What is the shape of JWST-ER1g?
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What is the significance of the Einstein ring in strong lensing?
What is the significance of the Einstein ring in strong lensing?
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What is the implication of the galaxy's compactness?
What is the implication of the galaxy's compactness?
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What is the role of the Navarro-Frenk-White (NFW) profile?
What is the role of the Navarro-Frenk-White (NFW) profile?
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Study Notes
JWST-ER1g Properties
- JWST-ER1g has a total mass of Mlens = 6.5-1.5 × 10^11 M⊙ within r = 6.6 kpc.
- Stellar mass within the Einstein radius is Mstars = (1.1-0.3 × 10^11) M⊙ for a Chabrier IMF.
- Lens mass is a factor of 5.9+4.1-1.6 higher than the stellar mass.
Possible Contributors to Lensing Mass
- Unlikely that significant fraction of lensing mass is in the form of gas.
- Observations of lensed quiescent galaxies and simulations find low gas masses.
- No hidden obscured starburst in JWST-ER1g, with an upper limit to the star formation rate of 63 M⊙ yr^-1.
Dark Matter Profile
- Dark matter density within the Einstein radius is a factor of ~2 higher than expected from scaling relations.
- Two possible options for the 'extra' dark matter:
- Total halo mass could be higher than expected from the canonical stellar mass-halo mass relation.
- Baryonic processes could lead to a dark matter profile that deviates from the NFW form.
Dark Matter within the Einstein Radius
- Dark matter mass within the Einstein radius is Mdm = 2.6+1.6-0.7 × 10^11 M⊙ for a NFW halo.
- Assumes a Navarro-Frenk-White (NFW) profile and the stellar mass-halo mass relation for z = 2.
Galaxy Properties
- JWST-ER1g is a quiescent galaxy, with an age of 1.9+0.3-0.6 Gyr and a low star formation rate of 4+19 M⊙ yr^-1.
- Galaxy is compact, with an observed effective radius of re = 1.9 ± 0.2 kpc.
- No obvious star-forming regions, tidal tails, or other irregularities in the residuals from the GALFIT fit.
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Description
Calculate the dark matter density within the Einstein radius using the photometric redshifts of the lens and source. This quiz covers the mass of JWST-ER1g inferred from the radius of the Einstein ring.
