4,174 research outputs found
A Measurement of the Angular Power Spectrum of the CMB from l = 100 to 400
We report on a measurement of the angular spectrum of the CMB between
and made at 144 GHz from Cerro Toco in the
Chilean altiplano. When the new data are combined with previous data at 30 and
40 GHz, taken with the same instrument observing the same section of sky, we
find: 1) a rise in the angular spectrum to a maximum with K at and a fall at , thereby localizing the peak
near ; and 2) that the anisotropy at has the
spectrum of the CMB.Comment: 4 pages, 2 figures. Revised version; includes Ned Wright's postscript
fix. Accepted by ApJL. Website at http://physics.princeton.edu/~cmb
The EBEX Experiment
EBEX is a balloon-borne polarimeter designed to measure the intensity and
polarization of the cosmic microwave background radiation. The measurements
would probe the inflationary epoch that took place shortly after the big bang
and would significantly improve constraints on the values of several
cosmological parameters. EBEX is unique in its broad frequency coverage and in
its ability to provide critical information about the level of polarized
Galactic foregrounds which will be necessary for all future CMB polarization
experiments. EBEX consists of a 1.5 m Dragone-type telescope that provides a
resolution of less than 8 arcminutes over four focal planes each of 4 degree
diffraction limited field of view at frequencies up to 450 GHz. The experiment
is designed to accommodate 330 transition edge bolometric detectors per focal
plane, for a total of up to 1320 detectors. EBEX will operate with frequency
bands centered at 150, 250, 350, and 450 GHz. Polarimetry is achieved with a
rotating achromatic half-wave plate. EBEX is currently in the design and
construction phase, and first light is scheduled for 2008.Comment: 13 pages, 10 figures. Figure 1 is changed from the one which appeared
in the Proceedings of the SPI
Implications of a High Angular Resolution Image of the Sunyaev-Zel'dovich Effect in RXJ1347-1145
The most X-ray luminous cluster known, RXJ1347-1145 (z=0.45), has been the
object of extensive study across the electromagnetic spectrum. We have imaged
the Sunyaev-Zel'dovich Effect (SZE) at 90 GHz (3.3 mm) in RXJ1347-1145 at 10"
resolution with the 64-pixel MUSTANG bolometer array on the Green Bank
Telescope (GBT), confirming a previously reported strong, localized enhancement
of the SZE 20" to the South-East of the center of X-ray emission. This
enhancement of the SZE has been interpreted as shock-heated (> 20 keV) gas
caused by an ongoing major (low mass-ratio) merger event. Our data support this
interpretation. We also detect a pronounced asymmetry in the projected cluster
pressure profile, with the pressure just east of the cluster core ~1.6 times
higher than just to the west. This is the highest resolution image of the SZE
made to date.Comment: 9 pages, 7 figures; accepted for publication in The Astrophysical
Journa
Galaxy Cluster Pressure Profiles as Determined by Sunyaev Zel'dovich Effect Observations with MUSTANG and Bolocam I: Joint Analysis Technique
We present a technique to constrain galaxy cluster pressure profiles by
jointly fitting Sunyaev-Zel'dovich effect (SZE) data obtained with MUSTANG and
Bolocam for the clusters Abell 1835 and MACS0647. Bolocam and MUSTANG probe
different angular scales and are thus highly complementary. We find that the
addition of the high resolution MUSTANG data can improve constraints on
pressure profile parameters relative to those derived solely from Bolocam. In
Abell 1835 and MACS0647, we find gNFW inner slopes of and , respectively when
and are constrained to 0.86 and 4.67 respectively. The fitted
SZE pressure profiles are in good agreement with X-ray derived pressure
profiles.Comment: 12 pages, 12 figures. Submitted to Ap
Determination of the branching ratios and
Improved branching ratios were measured for the decay in a
neutral beam at the CERN SPS with the NA31 detector: and .
From the first number an upper limit for and transitions in neutral kaon decay is derived. Using older results for the
Ke3/K3 fraction, the 3 branching ratio is found to be , about a factor three more
precise than from previous experiments
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