We discuss the nature of the possible high-l excess in the cosmic microwave background (CMB) anisotropy power spectrum observed by the Cosmic Background Imager (CBI). We probe the angular structure ...of the excess in the CBI deep fields and investigate whether it could be due to the scattering of CMB photons by hot electrons within clusters, which is the Sunyaev-Zel'dovich (SZ) effect. We estimate the density fluctuation parameters for amplitude, sigma sub(8), and shape, Gamma , from CMB primary anisotropy data and other cosmological data. We use the results of two separate hydrodynamic codes for Lambda CDM cosmologies, consistent with the allowed sigma sub(8) and Gamma values, to quantify the expected contribution from the SZ effect to the band powers of the CBI experiment and pass simulated SZ effect maps through our CBI analysis pipeline. The result is very sensitive to the value of sigma sub(8) and is roughly consistent with the observed power if sigma sub(8) approximately 1. We conclude that the CBI anomaly could be a result of the SZ effect for the class of Lambda CDM concordance models if sigma sub(8) is in the upper range of values allowed by current CMB and large-scale structure data.
Making maps from Planck LFI 30 GHz data Ashdown, M. A. J.; Baccigalupi, C.; Balbi, A. ...
Astronomy & astrophysics,
08/2007, Letnik:
471, Številka:
1
Journal Article
Recenzirano
Odprti dostop
This paper is one of a series describing the performance and accuracy of map-making codes as assessed by the Planck CTP working group. We compare the performance of multiple codes written by ...different groups for making polarized maps from Planck-sized, all-sky cosmic microwave background (CMB) data. Three of the codes are based on a destriping algorithm, whereas the other three are implementations of a maximum-likelihood algorithm. Previous papers in the series described simulations at 100 GHz (Poutanen et al. 2006, A&A, 449, 1311) and 217 GHz (Ashdown et al. 2007, A&A, 467, 761). In this paper we make maps (temperature and polarisation) from the simulated one-year observations of four 30 GHz detectors of Planck Low Frequency Instrument (LFI). We used Planck Level S simulation pipeline to produce the observed time-ordered-data streams (TOD). Our previous studies considered polarisation observations for the CMB only. For this paper we increased the realism of the simulations and included polarized galactic foregrounds in our sky model, which is based on the version 0.1 of the Planck reference sky. Our simulated TODs comprised dipole, CMB, diffuse galactic emissions, extragalactic radio sources, and detector noise. The strong subpixel signal gradients arising from the foreground signals couple to the output map through the map-making and cause an error (signal error) in the maps. Destriping codes have smaller signal error than the maximum-likelihood codes. We examined a number of schemes to reduce this error. On the other hand, the maximum-likelihood map-making codes can produce maps with lower residual noise than destriping codes.
We have compared the cosmic microwave background (CMB) temperature anisotropy maps made from one-year time ordered data (TOD) streams that simulated observations of the originally planned 100 GHz ...Planck Low Frequency Instrument (LFI). The maps were made with three different codes. Two of these, ROMA and MapCUMBA, were implementations of maximum-likelihood (ML) map-making, whereas the third was an implementation of the destriping algorithm. The purpose of this paper is to compare these two methods, ML and destriping, in terms of the maps they produce and the angular power spectrum estimates derived from these maps. The difference in the maps produced by the two ML codes was found to be negligible. As expected, ML was found to produce maps with lower residual noise than destriping. In addition to residual noise, the maps also contain an error which is due to the effect of subpixel structure in the signal on the map-making method. This error is larger for ML than for destriping. If this error is not corrected a bias will be introduced in the power spectrum estimates. This study is related to Planck activities.
Fraley's Syndrome is a rare anatomic vascular malformation described in 1966 where an aberrant crossing vessel compresses the upper infundibulum and leads to upper calyx massive dilation. It is ...mostly asymptomatic and the diagnosis often missed; however, surgery is usually required for symptomatic cases. Open surgery is still frequently used while minimally invasive management is anecdotal in the literature. We report the first robot-assisted calyceo-pyelostomy.
An 18-year-old female patient presented with intermittent, recurring, severe left flank pain leading to insomnia, evolving in the last 3 months. A 3-phases computerized tomography scan (CT-scan) showed a rotated left kidney, with upper calyx massive dilation and thinning of the upper renal parenchyma without any evident obstacle. Cystocopy and retrograde pyelography were performed. It confirmed a single ureteral meatus, a single ureter, and a narrowed upper calyx with upper calyx dilation. An ureteral catheter (JJ stent) was inserted in the upper calyx and the patient was planned for surgical exploration. During robotic surgery, an abnormal crossing vessel was identified and the diagnosis of Fraley's syndrome was made intraoperatively. According to previous literature, a calyceo-pyelostomy with uncrossing of the upper major calyx and resection of the narrowed upper infundibulum was performed. Total operative time was 114 minutes, pneumoperitoneum time was 96 minutes, blood loss less than 10 ml, and patient was released on post-operative day 2. The ureteral stent was removed 4 weeks after the intervention. At 12 postoperative weeks, the patient had complete regression of pain and the 12 postoperative week CT-scan showed a reduction of the dilation and a patent anastomosis.
Fraley's syndrome is a rare entity. In our case, the diagnosis of Fraley syndrome was made intraoperatively after an extensive previous workup, underlining the difficulty to make this diagnosis. We report and provide a video of the first robot-assisted procedure for Fraley's syndrome in a nephron-sparing technique. Patient was pain-free at the 3-month.
We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400 deg^{2} patch of sky centered on RA 0 h, Dec. ...-57.5°. The combined maps reach a depth of 57 nK deg in Stokes Q and U in a band centered at 150 GHz. Planck has observed the full sky in polarization at seven frequencies from 30 to 353 GHz, but much less deeply in any given region (1.2 μK deg in Q and U at 143 GHz). We detect 150×353 cross-correlation in B modes at high significance. We fit the single- and cross-frequency power spectra at frequencies ≥150 GHz to a lensed-ΛCDM model that includes dust and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r), using a prior on the frequency spectral behavior of polarized dust emission from previous Planck analysis of other regions of the sky. We find strong evidence for dust and no statistically significant evidence for tensor modes. We probe various model variations and extensions, including adding a synchrotron component in combination with lower frequency data, and find that these make little difference to the r constraint. Finally, we present an alternative analysis which is similar to a map-based cleaning of the dust contribution, and show that this gives similar constraints. The final result is expressed as a likelihood curve for r, and yields an upper limit r_{0.05}<0.12 at 95% confidence. Marginalizing over dust and r, lensing B modes are detected at 7.0σ significance.
We present an analysis of new VLT/MUSE optical imaging spectroscopic data of 2MASX J23453268–0449256 (J2345–0449), a nearby (
z
= 0.0755) massive (
M
stellar
= 4 × 10
11
M
⊙
) spiral galaxy. This ...is a particularly interesting source for a study of active galactic nucleus (AGN) feedback since it hosts two pairs of bright, giant radio jets and a massive, luminous X-ray halo, but it has no massive bulge. The galaxy has a 24 kpc wide ring of molecular gas, and a source-averaged star formation rate that is factors 30 to 70 lower than expected from the Kennicutt-Schmidt law. With MUSE, we have analyzed the stellar continuum and bright optical line emission and have constrained the spatially resolved past and present star formation on scales of approximately 1 kpc. More than 93% of the stellar mass formed ≥10 Gyrs ago including in the disk. Optical emission from the AGN is very faint and contributes 2% of the continuum around the nucleus at most. Most line emission is predominantly excited by shocks and old stellar populations except in 13 young star-forming regions that formed ≤11 Myrs ago, of which only seven are associated with the molecular ring (the others are at larger radii). They avoid a region of high electron densities aligned with the radio source, and form stars at efficiencies that are comparable to those in normal spiral galaxies. We discuss the implications of our findings for the regulation of star formation in galaxies through AGN feedback in the absence of competing mechanisms related to the presence of a massive stellar bulge, such as morphological quenching.
The Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) is a blind narrow-band (NB)
Hα
+NII imaging survey carried out with MegaCam at the Canada–France–Hawaii Telescope. The survey ...covers the whole Virgo cluster region from its core to one virial radius (104 deg
2
). The sensitivity of the survey is of
f
(
Hα
) ~ 4 × 10
−17
erg s
−1
cm
−2
(5
σ
detection limit) for point sources and Σ(
Hα
) ~ 2 × 10
−18
erg s
−1
cm
−2
arcsec
−2
(1
σ
detection limit at 3 arcsec resolution) for extended sources, making VESTIGE the deepest and largest blind NB survey of a nearby cluster. This paper presents the survey in all its technical aspects, including the survey design, the observing strategy, the achieved sensitivity in both the NB
Hα
+NII and in the broad-band
r
filter used for the stellar continuum subtraction, the data reduction, calibration, and products, as well as its status after the first observing semester. We briefly describe the
Hα
properties of galaxies located in a 4 × 1 deg
2
strip in the core of the cluster north of M87, where several extended tails of ionised gas are detected. This paper also lists the main scientific motivations for VESTIGE, which include the study of the effects of the environment on galaxy evolution, the fate of the stripped gas in cluster objects, the star formation process in nearby galaxies of different type and stellar mass, the determination of the
Hα
luminosity function and of the
Hα
scaling relations down to ~10
6
M
⊙
stellar mass objects, and the reconstruction of the dynamical structure of the Virgo cluster. This unique set of data will also be used to study the HII luminosity function in hundreds of galaxies, the diffuse
Hα
+NII emission of the Milky Way at high Galactic latitude, and the properties of emission line galaxies at high redshift.
One goal of cosmic microwave background (CMB) data analysis is to combine data at different frequencies, angular resolutions, and noise levels in order best to extract the component with a Planckian ...spectral behaviour. A multifrequency Wiener filtering method has been proposed in this context by Bouchet, Gispert & Puget and in parallel by Tegmark & Efstathiou. As shown by Bouchet & Gispert, this linear method is also convenient with which to estimate a priori, given a sky model and an experimental description, the residual errors on the CMB power spectrum assuming the foregrounds have been removed with this method. In this paper, we extend the method to the case in which additional polarization data are available. In particular, we derive the errors on the power spectra involving polarization and show numerical results for the specifications of the future CMB space missions MAP and Planck1 when it is assumed that the Galactic synchrotron and dust emission are respectively about 40 and 10 per cent polarized. We consider two underlying models for our study: we take a standard CDM model with τ = 0.1 for the extraction of E-mode polarization and ET cross-correlation; for B-mode polarization we consider a tilted CDM model with ns = 0.9, nt = −0.1 and T/S = 0.7. We find the following results. (1) The resulting fractional errors on E-mode polarization and TE cross-correlation power spectra are ≲ 10–30 per cent for 50 ≲ ℓ ≲ 1000 for Planck. The fractional errors are between 50 and 150 per cent for ℓ≤ 50. (2) The corresponding fractional errors for MAP are ≥ 300 per cent for most of the ℓ range. (3) The Wiener filtering gives extraction errors of ≤ twice the expected performance for the combined sensitivity of all the channels of Planck. For MAP, the corresponding degradation is ⋍ 4. (4) If, instead of individual modes, one considers band-power estimates with a logarithmic interval δℓ/ℓ = 0.2 then the fractional error for MAP drops to ≲ 100 per cent at the Doppler peak around ℓ⋍ 300 for the ET signal. (5) The fractional error for B-mode polarization detection is ≲ 100 per cent with Planck for ℓ≤ 100. A band-power estimate with Δℓ /ℓ = 0.2 reduces the fractional errors to ≤ 25 per cent for 20 ≤ℓ≤ 100.
Planck intermediate results Ade, P; Aghanim, N; Alves, M ...
Astronomy and astrophysics (Berlin),
02/2016, Letnik:
586
Journal Article
Recenzirano
Odprti dostop
Within ten nearby (d< 450pc) Gould belt molecular clouds we evaluate statistically the relative orientation between the magnetic field projected on the plane of sky, inferred from the polarized ...thermal emission of Galactic dust observed by Planck at 353GHz, and the gas column density structures, quantified by the gradient of the column density, N sub(H). The selected regions, covering several degrees in size, are analysed at an effective angular resolution of 10' FWHM, thus sampling physical scales from 0.4 to 40pc in the nearest cloud. The column densities in the selected regions range from N sub(H)approximate 10 super(21) to10 super(23)cm super(-2), and hence they correspond to the bulk of the molecular clouds. The relative orientation is evaluated pixel by pixel and analysed in bins of column density using the novel statistical tool called "histogram of relative orientations". Throughout this study, we assume that the polarized emission observed by Planck at 353GHz is representative of the projected morphology of the magnetic field in each region, i.e., we assume a constant dust grain alignment efficiency, independent of the local environment. Within most clouds we find that the relative orientation changes progressively with increasing N sub(H), from mostly parallel or having no preferred orientation to mostly perpendicular. In simulations of magnetohydrodynamic turbulence in molecular clouds this trend in relative orientation is a signature of Alfvenic or sub-Alfvenic turbulence, implying that the magnetic field is significant for the gas dynamics at the scales probed by Planck. We compare the deduced magnetic field strength with estimates we obtain from other methods and discuss the implications of the Planck observations for the general picture of molecular cloud formation and evolution.
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