2018ApJ...867...24D -
Astrophys. J., 867, 24-24 (2018/November-1)
Probing dark matter subhalos in galaxy clusters using highly magnified stars.
DAI L., VENUMADHAV T., KAUROV A.A. and MIRALDA-ESCUDE J.
Abstract (from CDS):
Luminous stars in background galaxies straddling the lensing caustic of a foreground galaxy cluster can be individually detected due to extreme magnification factors of ∼102-103, as recently observed in deep HST images. We propose a direct method to probe the presence of dark matter subhalos in galaxy clusters by measuring the astrometric perturbation they induce on the image positions of magnified stars or bright clumps: lensing by subhalos breaks the symmetry of a smooth critical curve, traced by the midpoints of close image pairs. For the giant arc at z = 0.725 behind the lensing cluster Abell 370 at z = 0.375, a promising target for detecting image pairs of stars, we find that subhalos of masses in the range of 106-108 M☉ with the abundance predicted in the cold dark matter theory should typically imprint astrometric distortions at the level of 20-80 mas. We estimate that ∼10 hr integrations with JWST at ∼1-3 µm may uncover several magnified stars whose image doublets will reveal the subhalo-induced structures of the critical curve. This method can probe a dynamic range in the subhalo-to-cluster halo mass ratio of m/M ∼ 10–7-10–9, thereby placing new constraints on the nature of dark matter.
Abstract Copyright:
© 2018. The American Astronomical Society. All rights reserved.
Journal keyword(s):
dark matter - galaxies: clusters: general - gravitational lensing: strong - supergiants
Simbad objects:
5
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2018ApJ...867...24D and select 'bookmark this link' or equivalent in the popup menu