1,243 research outputs found
Revised planet brightness temperatures using the Planck /LFI 2018 data release
Aims. We present new estimates of the brightness temperatures of Jupiter, Saturn, Uranus, and Neptune based on the measurements carried in 2009-2013 by Planck/LFI at 30, 44, and 70 GHz and released to the public in 2018. This work extends the results presented in the 2013 and 2015 Planck/LFI Calibration Papers, based on the data acquired in 2009-2011. Methods. Planck observed each planet up to eight times during the nominal mission. We processed time-ordered data from the 22 LFI radiometers to derive planet antenna temperatures for each planet and transit. We accounted for the beam shape, radiometer bandpasses, and several systematic effects. We compared our results with the results from the ninth year of WMAP, Planck/HFI observations, and existing data and models for planetary microwave emissivity. Results. For Jupiter, we obtain Tb = 144.9, 159.8, 170.5 K (\ub1 0.2 K at 1\u3c3, with temperatures expressed using the Rayleigh-Jeans scale) at 30, 44 and 70 GHz, respectively, or equivalently a band averaged Planck temperature Tb(ba) = 144.7, 160.3, 171.2 K in good agreement with WMAP and existing models. A slight excess at 30 GHz with respect to models is interpreted as an effect of synchrotron emission. Our measures for Saturn agree with the results from WMAP for rings Tb = 9.2 \ub1 1.4, 12.6 \ub1 2.3, 16.2 \ub1 0.8 K, while for the disc we obtain Tb = 140.0 \ub1 1.4, 147.2 \ub1 1.2, 150.2 \ub1 0.4 K, or equivalently a Tb(ba) = 139.7, 147.8, 151.0 K. Our measures for Uranus (Tb = 152 \ub1 6, 145 \ub1 3, 132.0 \ub1 2 K, or Tb(ba) = 152, 145, 133 K) and Neptune (Tb = 154 \ub1 11, 148 \ub1 9, 128 \ub1 3 K, or Tb(ba) = 154, 149, 128 K) agree closely with WMAP and previous data in literature
Planck 2015 results. V. LFI calibration
We present a description of the pipeline used to calibrate the Planck Low Frequency Instrument (LFI) timelines into thermodynamic temperatures for the Planck 2015 data release, covering four years of uninterrupted operations. As in the 2013 data release, our calibrator is provided by the spin-synchronous modulation of the cosmic microwave background dipole, but we now use the orbital component, rather than adopting the Wilkinson Microwave Anisotropy Probe (WMAP) solar dipole. This allows our 2015 LFI analysis to provide an independent Solar dipole estimate, which is in excellent agreement with that of HFI and within 1σ (0.3% in amplitude) of the WMAP value. This 0.3% shift in the peak-to-peak dipole temperature from WMAP and a general overhaul of the iterative calibration code increases the overall level of the LFI maps by 0.45% (30 GHz), 0.64% (44 GHz), and 0.82% (70 GHz) in temperature with respect to the 2013 Planck data release, thus reducing the discrepancy with the power spectrum measured by WMAP. We estimate that the LFI calibration uncertainty is now at the level of 0.20% for the 70 GHz map, 0.26% for the 44 GHz map, and 0.35% for the 30 GHz map. We provide a detailed description of the impact of all the changes implemented in the calibration since the previous data release
Mapping and analyzing ecosystem services hotspots and coldspots for sustainable spatial planning in the greater Asmara area, Eritrea
Rapid urbanization in African metropolises like the Greater Asmara Area, Eritrea, poses numerous environmental challenges, including soil sealing, loss of vegetation cover, threats to protected natural areas, and climate change, among others. Mapping and assessing ecosystem services, particularly analyzing their spatial and temporal distribution is crucial for sustainable spatial planning. This study aims at mapping and analyzing ecosystem services hotspots and coldspots dynamics in the Greater Asmara Area to identify recent trends and opportunities for enhancing ecosystem services supply. Utilizing remote sensing images, we produced land cover maps for 2009 and 2020 and mapped six ecosystem services through a lookup table approach. The study includes provisioning, regulating and maintenance, and cultural ecosystem services. We analyzed their spatio-temporal variations, identifying ecosystem services hotspots and coldspots and their changes over time. Results show that overall ecosystem services potential in the Greater Asmara Area remains low but stable, with some improvements. By 2020, areas with no ecosystem services potential decreased in southern regions like Gala Nefhi and Berik, and new hotspots and coldspots emerged in central Gala Nefhi. This pilot study demonstrates the feasibility and key challenges of the ecosystem services hotspots and coldspots approach for sustainable spatial planning in rapidly urbanizing African metropolitan regions. Despite limitations, the study offers valuable insights into ecosystem services potentials, and related hotspots and coldspots dynamics, raising awareness and paving the way for further research and application
Revisiting the Glick-Rogoff Current Account Model: An Application to the Current Accounts of BRICS Countries
Understanding what drives the changes in current accounts is one of the most important macroeconomic issues for developing countries. Excessive surpluses in current accounts can trigger trade wars, and excessive deficits in current accounts can, on the other hand, induce currency crises. The Glick-Rogoff (1995, Journal of Monetary Economics) model, which emphasizes productivity shocks at home and in the world, fit well with developed economies in the 1970s and 1980s. However, the Glick-Rogoff model fits poorly when it is applied to fast-growing BRICS countries for the period including the global financial crisis. We conclude that different mechanisms of current accounts work for developed and developing countries
Euclid preparation: VIII. The Complete Calibration of the Colour–Redshift Relation survey: VLT/KMOS observations and data release
The Complete Calibration of the Colour–Redshift Relation survey (C3R2) is a spectroscopic effort involving ESO and Keck facilities designed specifically to empirically calibrate the galaxy colour–redshift relation – P(z|C) to the Euclid depth (iAB = 24.5) and is intimately linked to the success of upcoming Stage IV dark energy missions based on weak lensing cosmology. The aim is to build a spectroscopic calibration sample that is as representative as possible of the galaxies of the Euclid weak lensing sample. In order to minimise the number of spectroscopic observations necessary to fill the gaps in current knowledge of the P(z|C), self-organising map (SOM) representations of the galaxy colour space have been constructed. Here we present the first results of an ESO@VLT Large Programme approved in the context of C3R2, which makes use of the two VLT optical and near-infrared multi-object spectrographs, FORS2 and KMOS. This data release paper focuses on high-quality spectroscopic redshifts of high-redshift galaxies observed with the KMOS spectrograph in the near-infrared H- and K-bands. A total of 424 highly-reliable redshifts are measured in the 1.3 ≤ z ≤ 2.5 range, with total success rates of 60.7% in the H-band and 32.8% in the K-band. The newly determined redshifts fill 55% of high (mainly regions with no spectroscopic measurements) and 35% of lower (regions with low-resolution/low-quality spectroscopic measurements) priority empty SOM grid cells. We measured Hα fluxes in a 1. 002 radius aperture from the spectra of the spectroscopically confirmed galaxies and converted them into star formation rates. In addition, we performed an SED fitting analysis on the same sample in order to derive stellar masses, E(B − V), total magnitudes, and SFRs. We combine the results obtained from the spectra with those derived via SED fitting, and we show that the spectroscopic failures come from either weakly star-forming galaxies (at z 2 galaxies
<em>Euclid</em>: The <em>r</em><sub>b</sub>−<em>M</em>* relation as a function of redshift I. The 5 7 10<sup>9</sup> M☉ black hole in NGC 1272
\ua9 The Authors 2024. Core ellipticals, which are massive early-type galaxies with almost constant inner surface brightness profiles, are the result of dry mergers. During these events, a binary black hole (BBH) is formed, destroying the original cuspy central regions of the merging objects and scattering stars that are not on tangential orbits. The size of the emerging core correlates with the mass of the finally merged black hole (BH). Therefore, the determination of the size of the core of massive early-type galaxies provides key insights not only into the mass of the black hole, but also into the origin and evolution of these objects. In this work, we report the first Euclid-based dynamical mass determination of a supermassive black hole (SMBH). To this end, we study the center of NGC 1272, the second most luminous elliptical galaxy in the Perseus cluster, combining the Euclid Visible Camera (VIS) photometry coming from the Early Release Observations (EROs) of the Perseus cluster with the Visible Integral-field Replicable Unit Spectrograph (VIRUS) spectroscopic observations at the Hobby-Eberly Telescope (HET). The core of NGC 1272 is detected on the Euclid VIS image. Its size is 1″. 29 \ub1 0″. 07 or 0.45 kpc, which was determined by fitting PSF-convolved core-S\ue9rsic and Nuker-law functions. We deproject the surface brightness profile of the galaxy, finding that the galaxy is axisymmetric and nearly spherical. The two-dimensional stellar kinematics of the galaxy is measured from the VIRUS spectra by deriving optimally regularized non-parametric line-of-sight velocity distributions. Dynamical models of the galaxy are constructed using our axisymmetric and triaxial Schwarzschild codes. We measure a BH mass of (5 \ub1 3)
7 109 M☉, which is in line with the expectation from the MBH−rb correlation, but is eight times larger than predicted by the MBH−σ correlation (at 1.8σ significance). The core size, rather than the velocity dispersion, allows one to select galaxies harboring the most massive BHs. The spatial resolution, wide area coverage, and depth of the Euclid (Wide and Deep) surveys allow us to find cores of passive galaxies that are larger than 2 kpc at a redshift of up to 1
Euclid: The search for primordial features
Primordial features, in particular oscillatory signals, imprinted in the primordial power spectrum of density perturbations represent a clear window of opportunity for detecting new physics at high-energy scales. Future spectroscopic and photometric measurements from the Euclid space mission will provide unique constraints on the primordial power spectrum, thanks to the redshift coverage and high-accuracy measurement of nonlinear scales, thus allowing us to investigate deviations from the standard power-law primordial power spectrum. We consider two models with primordial undamped oscillations superimposed on the matter power spectrum described by 1 + A(X) sin (omega(X)Xi(X) + 2 pi phi(X)), one linearly spaced in k space with Xi(lin) equivalent to k/k(*) where k(*) = 0.05 Mpc(-1) and the other logarithmically spaced in k space with Xi(log) equivalent to ln(k/k(*)). We note that AX is the amplitude of the primordial feature, omega(X) is the dimensionless frequency, and phi(X) is the normalised phase, where X = {lin, log}. We provide forecasts from spectroscopic and photometric primary Euclid probes on the standard cosmological parameters Omega(m,0), Omega(b,0), h, ns, and sigma(8), and the primordial feature parameters A(X), omega(X), and phi(X). We focus on the uncertainties of the primordial feature amplitude A(X) and on the capability of Euclid to detect primordial features at a given frequency. We also study a nonlinear density reconstruction method in order to retrieve the oscillatory signals in the primordial power spectrum, which are damped on small scales in the late-time Universe due to cosmic structure formation. Finally, we also include the expected measurements from Euclid's galaxy-clustering bispectrum and from observations of the cosmic microwave background (CMB). We forecast uncertainties in estimated values of the cosmological parameters with a Fisher matrix method applied to spectroscopic galaxy clustering (GC(sp)), weak lensing (WL), photometric galaxy clustering (GC(ph)), the cross correlation (XC) between GC(ph) and WL, the spectroscopic galaxy clustering bispectrum, the CMB temperature and E-mode polarisation, the temperature-polarisation cross correlation, and CMB weak lensing. We consider two sets of specifications for the Euclid probes (pessimistic and optimistic) and three di fferent CMB experiment configurations, that is, Planck, Simons Observatory (SO), and CMB Stage-4 (CMB-S4). We find the following percentage relative errors in the feature amplitude with Euclid primary probes: for the linear (logarithmic) feature model, with a fiducial value of A(X) = 0.01, omega(X) = 10, and phi(X) = 0.21% (22%) in the pessimistic settings and 18% (18%) in the optimistic settings at a 68.3% confidence level (CL) using GC(sp) +WL +GC(ph) +XC. While the uncertainties on the feature amplitude are strongly dependent on the frequency value when single Euclid probes are considered, we find robust constraints on A X from the combination of spectroscopic and photometric measurements over the frequency range of (1, 10(2.1)). Due to the inclusion of numerical reconstruction, the GC(sp) bispectrum, SO-like CMB reduces the uncertainty on the primordial feature amplitude by 32%-48%, 50%-65%, and 15%-50%, respectively.Combining all the sources of information explored expected from Euclid in combination with the future SO-like CMB experiment, we forecast A(lin) similar or equal to 0.010 +/- 0.001 at a 68.3% CL and A(log) similar or equal to 0.010 +/- 0.001 for GC(sp)(PS rec + BS) +WL +GC(ph) +XC +SO-like for both the optimistic and pessimistic settings over the frequency range (1, 10(2.1))
Euclid: Early Release Observations -- A glance at free-floating new-born planets in the sigma Orionis cluster
We provide an early assessment of the imaging capabilities of the Euclid
space mission to probe deeply into nearby star-forming regions and associated
very young open clusters, and in particular to check to what extent it can shed
light on the new-born free-floating planet population. This paper focuses on a
low-reddening region observed in just one Euclid pointing where the dust and
gas has been cleared out by the hot sigma Orionis star. One late-M and six
known spectroscopically confirmed L-type substellar members in the sigma
Orionis cluster are used as benchmarks to provide a high-purity procedure to
select new candidate members with Euclid. The exquisite angular resolution and
depth delivered by the Euclid instruments allow us to focus on bona-fide point
sources. A cleaned sample of sigma Orionis cluster substellar members has been
produced and the initial mass function (IMF) has been estimated by combining
Euclid and Gaia data. Our sigma Orionis substellar IMF is consistent with a
power-law distribution with no significant steepening at the planetary-mass
end. No evidence of a low-mass cutoff is found down to about 4 Jupiter masses
at the young age (3 Myr) of the sigma Orionis open cluster.Comment: 13 pages, 10 figures, submitted to the A&A special issue on "Euclid
on the sky
Euclid: Early Release Observations -- Unveiling the morphology of two Milky Way globular clusters out to their periphery
As part of the Euclid Early Release Observations (ERO) programme, we analyse
deep, wide-field imaging from the VIS and NISP instruments of two Milky Way
globular clusters (GCs), namely NGC 6254 (M10) and NGC 6397, to look for
observational evidence of their dynamical interaction with the Milky Way. We
search for such an interaction in the form of structural and morphological
features in the clusters' outermost regions, which are suggestive of the
development of tidal tails on scales larger than those sampled by the ERO
programme. Our multi-band photometric analysis results in deep and well-behaved
colour-magnitude diagrams that, in turn, enable an accurate membership
selection. The surface brightness profiles built from these samples of member
stars are the deepest ever obtained for these two Milky Way GCs, reaching down
to mag~arcsec, which is about mag arcsec below
the current limit. The investigation of the two-dimensional density map of NGC
6254 reveals an elongated morphology of the cluster peripheries in the
direction and with the amplitude predicted by -body simulations of the
cluster's dynamical evolution, at high statistical significance. We interpret
this as strong evidence for the first detection of tidally induced
morphological distortion around this cluster. The density map of NGC 6397
reveals a slightly elliptical morphology, in agreement with previous studies,
which requires further investigation on larger scales to be properly
interpreted. This ERO project thus demonstrates the power of Euclid in studying
the outer regions of GCs at an unprecedented level of detail, thanks to the
combination of large field of view, high spatial resolution, and depth enabled
by the telescope. Our results highlight the future Euclid survey as the ideal
data set to investigate GC tidal tails and stellar streams.Comment: 15 pages, 18 figures. Paper accepted as part of the A&A special issue
`Euclid on Sky', which contains Euclid key reference papers and first results
from the Euclid Early Release Observation
Euclid: ERO -- NISP-only sources and the search for luminous galaxies
This paper presents a search for high redshift galaxies from the Euclid Early
Release Observations program "Magnifying Lens." The 1.5 deg area covered by
the twin Abell lensing cluster fields is comparable in size to the few other
deep near-infrared surveys such as COSMOS, and so provides an opportunity to
significantly increase known samples of rare UV-bright galaxies at
(). Beyond their still uncertain role in
reionisation, these UV-bright galaxies are ideal laboratories from which to
study galaxy formation and constrain the bright-end of the UV luminosity
function. Of the 501994 sources detected from a combined , , and NISP detection image, 168 do not have any appreciable
VIS/ flux. These objects span a range in spectral colours, separated
into two classes: 139 extremely red sources; and 29 Lyman-break galaxy
candidates. Best-fit redshifts and spectral templates suggest the former is
composed of both dusty star-forming galaxies and
quiescent systems. The latter is composed of more homogeneous Lyman break
galaxies at . In both cases, contamination by L- and T-type dwarfs
cannot be ruled out with Euclid images alone. Additional contamination from
instrumental persistence is investigated using a novel time series analysis.
This work lays the foundation for future searches within the Euclid Deep
Fields, where thousands more Lyman break systems and extremely red
sources will be identified.Comment: 22 pages, 13 figures, paper submitted as part of the A&A special
issue `Euclid on Sky', which contains Euclid key reference papers and first
results from the Euclid Early Release Observation
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