804 research outputs found
On the proper kinetic quadrupole CMB removal and the quadrupole anomalies
It has been pointed out recently that the quadrupole-octopole alignment in
the CMB data is significantly affected by the so-called kinetic Doppler
quadrupole (DQ), which is the temperature quadrupole induced by our proper
motion. Assuming our velocity is the dominant contribution to the CMB dipole we
have v/c = beta = (1.231 +/- 0.003) * 10^{-3}, which leads to a non-negligible
DQ of order beta^2. Here we stress that one should properly take into account
that CMB data are usually not presented in true thermodynamic temperature,
which induces a frequency dependent boost correction. The DQ must therefore be
multiplied by a frequency-averaged factor, which we explicitly compute for
several CMB maps finding that it varies between 1.67 and 2.47. This is often
neglected in the literature and turns out to cause a small but non-negligible
difference in the significance levels of some quadrupole-related statistics.
For instance the alignment significance in the SMICA 2013 map goes from
2.3sigma to 3.3sigma, with the frequency dependent DQ, instead of 2.9sigma
ignoring the frequency dependence in the DQ. Moreover as a result of a proper
DQ removal, the agreement across different map-making techniques is improved.Comment: v2: improvements to the text; 2 figures and several references added;
results unchanged. [14 pages, 3 tables, 2 figures
Effect of Harmonicity on the Detection of a Signal in a Complex Masker and on Spatial Release from Masking
The amount of masking of sounds from one source (signals) by sounds from a competing source (maskers) heavily depends on the sound characteristics of the masker and the signal and on their relative spatial location. Numerous studies investigated the ability to detect a signal in a speech or a noise masker or the effect of spatial separation of signal and masker on the amount of masking, but there is a lack of studies investigating the combined effects of many cues on the masking as is typical for natural listening situations. The current study using free-field listening systematically evaluates the combined effects of harmonicity and inharmonicity cues in multi-tone maskers and cues resulting from spatial separation of target signal and masker on the detection of a pure tone in a multi-tone or a noise masker. A linear binaural processing model was implemented to predict the masked thresholds in order to estimate whether the observed thresholds can be accounted for by energetic masking in the auditory periphery or whether other effects are involved. Thresholds were determined for combinations of two target frequencies (1 and 8 kHz), two spatial configurations (masker and target either co-located or spatially separated by 90 degrees azimuth), and five different masker types (four complex multi-tone stimuli, one noise masker). A spatial separation of target and masker resulted in a release from masking for all masker types. The amount of masking significantly depended on the masker type and frequency range. The various harmonic and inharmonic relations between target and masker or between components of the masker resulted in a complex pattern of increased or decreased masked thresholds in comparison to the predicted energetic masking. The results indicate that harmonicity cues affect the detectability of a tonal target in a complex masker
The MUSE-Wide Survey: A first catalogue of 831 emission line galaxies
We present a first instalment of the MUSE-Wide survey, covering an area of
22.2 arcmin (corresponding to 20% of the final survey) in the
CANDELS/Deep area of the Chandra Deep Field South. We use the MUSE integral
field spectrograph at the ESO VLT to conduct a full-area spectroscopic mapping
at a depth of 1h exposure time per 1 arcmin pointing. We searched for
compact emission line objects using our newly developed LSDCat software based
on a 3-D matched filtering approach, followed by interactive classification and
redshift measurement of the sources. Our catalogue contains 831 distinct
emission line galaxies with redshifts ranging from 0.04 to 6. Roughly one third
(237) of the emission line sources are Lyman emitting galaxies with , only four of which had previously measured spectroscopic redshifts.
At lower redshifts 351 galaxies are detected primarily by their [OII] emission
line (), 189 by their [OIII] line (), and 46 by their H line (). Comparing our spectroscopic redshifts to photometric redshift estimates
from the literature, we find excellent agreement for with a median
of only and an outlier rate of 6%, however a
significant systematic offset of and an outlier rate of 23%
for Ly emitters at . Together with the catalogue we also release
1D PSF-weighted extracted spectra and small 3D datacubes centred on each of the
831 sources.Comment: 24 pages, 14 figures, accepted for publication in A&A, data products
are available for download from http://muse-vlt.eu/science/muse-wide-survey/
and later via the CD
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