317 research outputs found
Searching for bulk motions in the ICM of massive, merging clusters with Chandra CCD data
We search for bulk motions in the intracluster medium (ICM) of massive
clusters showing evidence of an ongoing or recent major merger with spatially
resolved spectroscopy in {\sl Chandra} CCD data. We identify a sample of 6
merging clusters with 150 ks {\sl Chandra} exposure in the redshift range
. By performing X-ray spectral analysis of projected ICM regions
selected according to their surface brightness, we obtain the projected
redshift maps for all of these clusters. After performing a robust analysis of
the statistical and systematic uncertainties in the measured X-ray redshift
, we check whether or not the global distribution
differs from that expected when the ICM is at rest. We find evidence of
significant bulk motions at more than 3 in A2142 and A115, and less
than 2 in A2034 and A520. Focusing on single regions, we identify
significant localized velocity differences in all of the merging clusters. We
also perform the same analysis on two relaxed clusters with no signatures of
recent mergers, finding no signs of bulk motions, as expected. Our results
indicate that deep {\sl Chandra} CCD data enable us to identify the presence of
bulk motions at the level of 1000\ in the ICM
of massive merging clusters at . Although the CCD spectral
resolution is not sufficient for a detailed analysis of the ICM dynamics, {\sl
Chandra} CCD data constitute a key diagnostic tool complementing X-ray
bolometers on board future X-ray missions
Precision cosmology from future lensed gravitational wave and electromagnetic signals
The standard siren approach of gravitational wave cosmology appeals to the
direct luminosity distance estimation through the waveform signals from
inspiralling double compact binaries, especially those with electromagnetic
counterparts providing redshifts. It is limited by the calibration
uncertainties in strain amplitude and relies on the fine details of the
waveform. The Einstein Telescope is expected to produce
gravitational wave detections per year, of which will be lensed. Here
we report a waveform-independent strategy to achieve precise cosmography by
combining the accurately measured time delays from strongly lensed
gravitational wave signals with the images and redshifts observed in the
electromagnetic domain. We demonstrate that just 10 such systems can provide a
Hubble constant uncertainty of for a flat Lambda Cold Dark Matter
universe in the era of third generation ground-based detectors
1-(2-FurylmethylÂene)-2-(2-nitroÂphenÂyl)hydrazine
The title Schiff base compound, C11H9N3O3, was obtained from a condensation reaction of furan-2-carbaldehyde and 2-nitroÂphenylÂhydrazine. The molÂecule is roughly planar, the largest deviation from the mean plane defined by all non-H atoms being 0.097 (4). An in ntraÂmolecular N—H⋯O hydrogen bond might influence the planar conformation of the molÂecule. In the crystal, weak C—H⋯O hydrogen bonds link the molÂecules, forming a chain
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