تقرير
The inner density profile of an elliptical galaxy at z=1.15 from gravitational lensing
| العنوان: | The inner density profile of an elliptical galaxy at z=1.15 from gravitational lensing |
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| المؤلفون: | Stacey, H. R., O'Riordan, C. M., Vegetti, S., Powell, D. M., Auger, M. W., Despali, G. |
| سنة النشر: | 2021 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Astrophysics of Galaxies |
| الوصف: | The density profiles of lensing galaxies are typically parameterised by singular power-law models with a logarithmic slope close to isothermal ($\zeta=2$). This is sufficient to fit the lensed emission near the Einstein radius but may not be sufficient when extrapolated to smaller or larger radii if the large-scale density profile is more complex. Here, we consider a broken power-law model for the density profile of an elliptical galaxy at $z=1.15$ using observations with the Atacama Large (sub-)Millimetre Array of the strong gravitational lens system SPT0532$-$50. This is the first application of such a model to real data. We find the lensed emission is best fit by a density profile that is sub-isothermal ($\zeta = 1.87^{+0.02}_{-0.03}$) near the Einstein radius and steepens to super-isothermal ($\zeta = 2.14^{+0.03}_{-0.02}$) at around half the Einstein radius, demonstrating that the lensing data probes the mass distribution inside the region probed by the lensed images. Assuming that a broken power-law is the underlying truth, we find that a single power-law would result in a $10\pm1$ percent underestimate of the Hubble constant from time-delay cosmography. Our results suggest that a broken power-law could be useful for precision lens modelling and probing the structural evolution of elliptical galaxies. Comment: Withdrawn pending further testing |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2109.10929 |
| رقم الأكسشن: | edsarx.2109.10929 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |