Flashlights: Properties of Highly Magnified Images Near Cluster Critical Curves in the Presence of Dark Matter Subhalos. (arXiv:2304.06064v1 [astro-ph.CO])

Flashlights: Properties of Highly Magnified Images Near Cluster Critical Curves in the Presence of Dark Matter Subhalos. (arXiv:2304.06064v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Williams_L/0/1/0/all/0/1">Liliya L.R. Williams</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kelly_P/0/1/0/all/0/1">Patrick L. Kelly</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Treu_T/0/1/0/all/0/1">Tommaso Treu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Amruth_A/0/1/0/all/0/1">Alfred Amruth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Diego_J/0/1/0/all/0/1">Jose M. Diego</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_S/0/1/0/all/0/1">Sung Kei Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Meena_A/0/1/0/all/0/1">Ashish K. Meena</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zitrin_A/0/1/0/all/0/1">Adi Zitrin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Broadhurst_T/0/1/0/all/0/1">Thomas J. Broadhurst</a>

Dark matter subhalos with extended profiles and density cores, and globular
stars clusters of mass $10^6-10^8 M_odot$, that live near the critical curves
in galaxy cluster lenses can potentially be detected through their lensing
magnification of stars in background galaxies. In this work we study the effect
such subhalos have on lensed images, and compare to the case of more well
studied microlensing by stars and black holes near critical curves. We find
that the cluster density gradient and the extended mass distribution of
subhalos are important in determining image properties. Both lead to an
asymmetry between the image properties on the positive and negative parity
sides of the cluster that is more pronounced than in the case of microlensing.
For example, on the negative parity side, subhalos with cores larger than about
$50,$pc do not generate any images with magnification above $sim 100$ outside
of the immediate vicinity of the cluster critical curve. We discuss these
factors using analytical and numerical analysis, and exploit them to identify
observable signatures of subhalos: subhalos create pixel-to-pixel flux
variations of $gtrsim 0.1$ magnitudes, on the positive parity side of
clusters. These pixels tend to cluster around (otherwise invisible) subhalos.
Unlike in the case of microlensing, signatures of subhalo lensing can be found
up to $1”$ away from the critical curves of massive clusters.

Dark matter subhalos with extended profiles and density cores, and globular
stars clusters of mass $10^6-10^8 M_odot$, that live near the critical curves
in galaxy cluster lenses can potentially be detected through their lensing
magnification of stars in background galaxies. In this work we study the effect
such subhalos have on lensed images, and compare to the case of more well
studied microlensing by stars and black holes near critical curves. We find
that the cluster density gradient and the extended mass distribution of
subhalos are important in determining image properties. Both lead to an
asymmetry between the image properties on the positive and negative parity
sides of the cluster that is more pronounced than in the case of microlensing.
For example, on the negative parity side, subhalos with cores larger than about
$50,$pc do not generate any images with magnification above $sim 100$ outside
of the immediate vicinity of the cluster critical curve. We discuss these
factors using analytical and numerical analysis, and exploit them to identify
observable signatures of subhalos: subhalos create pixel-to-pixel flux
variations of $gtrsim 0.1$ magnitudes, on the positive parity side of
clusters. These pixels tend to cluster around (otherwise invisible) subhalos.
Unlike in the case of microlensing, signatures of subhalo lensing can be found
up to $1”$ away from the critical curves of massive clusters.

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