785 research outputs found
Measurement of redshift dependent cross correlation of HSC clusters and Fermi rays
The cross-correlation study of the unresolved -ray background (UGRB)
with galaxy clusters has a potential to reveal the nature of the UGRB. In this
paper, we perform a cross-correlation analysis between -ray data by the
Fermi Large Area Telescope (Fermi-LAT) and a galaxy cluster catalogue from the
Subaru Hyper Suprime-Cam (HSC) survey. The Subaru HSC cluster catalogue
provides a wide and homogeneous large-scale structure distribution out to the
high redshift at , which has not been accessible in previous
cross-correlation studies. We conduct the cross-correlation analysis not only
for clusters in the all redshift range () of the survey, but
also for subsamples of clusters divided into redshift bins, the low redshift
bin () and the high redshift bin (), to utilize
the wide redshift coverage of the cluster catalogue. We find the evidence of
the cross-correlation signals with the significance of 2.0-2.3 for all
redshift and low-redshift cluster samples. On the other hand, for high-redshift
clusters, we find the signal with weaker significance level (1.6-1.9).
We also compare the observed cross-correlation functions with predictions of a
theoretical model in which the UGRB originates from -ray emitters such
as blazars, star-forming galaxies and radio galaxies. We find that the detected
signal is consistent with the model prediction.Comment: 11 pages, 24 figures, accepted by MNRA
Line-of-sight structure of troughs identified in Subaru Hyper Suprime-Cam Year 3 weak lensing mass maps
We perform the weak lensing mass mapping analysis to identify troughs, which
are defined as local minima in the mass map. Since weak lensing probes
projected matter along the line-of-sight, these troughs can be produced by
single voids or multiple voids projected along the line-of-sight. To scrutinise
the origins of the weak lensing troughs, we systematically investigate the
line-of-sight structure of troughs selected from the latest Subaru Hyper
Suprime-Cam (HSC) Year 3 weak lensing data covering .
From a curved sky mass map constructed with the HSC data, we identify 15
troughs with the signal-to-noise ratio higher than and address their
line-of-sight density structure utilizing redshift distributions of two galaxy
samples, photometric luminous red galaxies observed by HSC and spectroscopic
galaxies detected by Baryon Oscillation Spectroscopic Survey. While most of
weak lensing signals due to the troughs are explained by multiple voids aligned
along the line-of-sight, we find that two of the 15 troughs potentially
originate from single voids at redshift . The single void
interpretation appears to be consistent with our three-dimensional mass mapping
analysis. We argue that single voids can indeed reproduce observed weak lensing
signals at the troughs if these voids are not spherical but are highly
elongated along the line-of-sight direction.Comment: 14 pages, 12 figures, submitted to MNRA
Detection of the Gravitational Lens Magnifying a Type Ia Supernova
Objects of known brightness, like Type Ia supernovae (SNIa), can be used to
measure distances. If a massive object warps spacetime to form multiple images
of a background SNIa, a direct test of cosmic expansion is also possible.
However, these lensing events must first be distinguished from other rare
phenomena. Recently, a supernova was found to shine much brighter than normal
for its distance, which resulted in a debate: was it a new type of
superluminous supernova or a normal SNIa magnified by a hidden gravitational
lens? Here we report that a spectrum obtained after the supernova faded away
shows the presence of a foreground galaxy--the first found to strongly magnify
a SNIa. We discuss how more lensed SNIa may be found than previously predicted.Comment: 32 pages, 10 figures. Accepted for publication in Scienc
Essential self-adjointness for combinatorial Schr\"odinger operators II- Metrically non complete graphs
We consider weighted graphs, we equip them with a metric structure given by a
weighted distance, and we discuss essential self-adjointness for weighted graph
Laplacians and Schr\"odinger operators in the metrically non complete case.Comment: Revisited version: Ognjen Milatovic wrote to us that he had
discovered a gap in the proof of theorem 4.2 of our paper. As a consequence
we propose to make an additional assumption (regularity property of the
graph) to this theorem. A new subsection (4.1) is devoted to the study of
this property and some details have been changed in the proof of theorem 4.
Planck Sunyaev-Zel'dovich Cluster Mass Calibration using Hyper Suprime-Cam Weak Lensing
Using 140 deg Subaru Hyper Suprime-Cam (HSC) survey data, we stack
the weak lensing (WL) signal around five Planck clusters found within the
footprint. This yields a 15 detection of the mean Planck cluster mass
density profile. The five Planck clusters span a relatively wide mass range,
with a mean mass of . The ratio of the stacked
Planck Sunyaev-Zel'dovich (SZ) mass to the stacked WL mass is . This mass bias is
consistent with previous WL mass calibrations of Planck clusters within the
errors. We discuss the implications of our findings for the calibration of SZ
cluster counts and the much discussed tension between Planck SZ cluster counts
and Planck CDM cosmology.Comment: 12 pages, 2 tables, 7 figures, accepted to PASJ special issu
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