New Constraints on variations of the fine structure constant from CMB anisotropies (2009)
Menegoni, Eloisa, Galli, Silvia, Bartlett, James, Melchiorri, Alessandro
We demonstrate that recent measurements of Cosmic Microwave Background temperature and polarization anisotropy made by the ACBAR, QUAD and BICEP experiments substantially improve the cosmological...
Giannantonio, Tommaso, Martinelli, Matteo, Silvestri, Alessandra, Melchiorri, Alessandro
We study the effects of modified theories of gravity on the cosmic microwave background (CMB) anisotropies power spectrum, and in particular on its large scales, where the integrated Sachs-Wolfe...
Calabrese, Erminia, Smidt, Joseph, Amblard, Alexandre, Cooray, Asantha, Melchiorri, Alessandro, Serra, Paolo, ...
We measure the skewness power spectrum of the Cosmic Microwave Background (CMB) anisotropies optimized for a detection of the secondary bispectrum generated by the correlation of the CMB lensing...
No Evidence for Dark Energy Dynamics from a Global Analysis of Cosmological Data (2009)
Serra, Paolo, Cooray, Asantha, Holz, Daniel E., Melchiorri, Alessandro, Pandolfi, Stefania, Sarkar, Devdeep
We use a variant of principal component analysis to investigate the possible temporal evolution of the dark energy equation of state, w(z). We constrain w(z) in multiple redshift bins, utilizing the...
CMB Lensing Constraints on Dark Energy and Modified Gravity Scenarios (2009)
Calabrese, Erminia, Cooray, Asantha, Martinelli, Matteo, Melchiorri, Alessandro, Pagano, Luca, Slosar, Anze, ...
Weak gravitational lensing leaves a characteristic imprint on the cosmic microwave background temperature and polarization angular power spectra. Here we investigate the possible constraints on the...
Determining the Neutrino Mass Hierarchy with Cosmology (2009)
De Bernardis, Francesco, Kitching, Thomas D., Heavens, Alan, Melchiorri, Alessandro
The combination of current large scale structure and cosmic microwave background (CMB) anisotropies data can place strong constraints on the sum of the neutrino masses. Here we show that future...
Cosmological constraints on the Hu-Sawicki modified gravity scenario (2009)
Martinelli, Matteo, Melchiorri, Alessandro, Amendola, Luca
In this paper we place new constraints on a f(R) modified gravity model recently proposed by Hu and Sawicki. After checking that the Hu and Sawicki model produces a viable cosmology, i.e. a matter...
Galli, Silvia, Melchiorri, Alessandro, Smoot, George F., Zahn, Oliver
We present new constraints on cosmic variations of Newton's gravitational constant by making use of the latest CMB data from WMAP, BOOMERANG, CBI and ACBAR experiments and independent constraints...
Pagano, Luca, De Bernardis, Paolo, De Troia, Grazia, Gubitosi, Giulia, Masi, Silvia, Melchiorri, Alessandro, ...
Cosmic Microwave Background experiments must achieve very accurate calibration of their polarization reference frame to avoid biasing the cosmological parameters. In particular, a wrong or inaccurate...
A Constraint on Planck-scale Modifications to Electrodynamics with CMB polarization data (2009)
Gubitosi, Giulia, Pagano, Luca, Amelino-Camelia, Giovanni, Melchiorri, Alessandro, Cooray, Asantha
We show that the Cosmic Microwave Background (CMB) polarization data gathered by the BOOMERanG 2003 flight and WMAP provide an opportunity to investigate {\it in-vacuo} birefringence, of a type...
Observing the Evolution of the Universe (2009)
Aguirre, James, Amblard, Alexandre, Ashoorioon, Amjad, Baccigalupi, Carlo, Balbi, Amedeo, Bartlett, James, ...
How did the universe evolve? The fine angular scale (l>1000) temperature and polarization anisotropies in the CMB are a Rosetta stone for understanding the evolution of the universe. Through detailed...
Lensed Cosmic Microwave Background Constraints on Post-General Relativity Parameters (2009)
Serra, Paolo, Cooray, Asantha, Daniel, Scott F., Caldwell, Robert, Melchiorri, Alessandro
The constraints on departures from general relativity (GR) at cosmological length scales due to cosmic microwave background (CMB) data are discussed. The departure from GR is measured by the ratio,...
A Multi-Parameter Investigation of Gravitational Slip (2009)
Daniel, Scott F., Caldwell, Robert R., Cooray, Asantha, Serra, Paolo, Melchiorri, Alessandro
A detailed analysis of gravitational slip, a new post-general relativity cosmological parameter characterizing the degree of departure of the laws of gravitation from general relativity on...
Delayed Recombination and Standard Rulers (2008)
De Bernardis, Francesco, Bean, Rachel, Galli, Silvia, Melchiorri, Alessandro, Silk, Joseph, Verde, Licia
Measurements of Baryonic Acoustic Oscillations in galaxy surveys have been recognized as a powerful tool for constraining dark energy. However, this method relies on the knowledge of the size of the...
CMBPol Mission Concept Study: Probing Inflation with CMB Polarization (2008)
Baumann, Daniel, Jackson, Mark G, Adshead, Peter, Amblard, Alexandre, Ashoorioon, Amjad, Bartolo, Nicola, ...
We summarize the utility of precise cosmic microwave background (CMB) polarization measurements as probes of the physics of inflation. We focus on the prospects for using CMB measurements to...
CMBPol Mission Concept Study: Probing Inflation with CMB Polarization (2008)
Baumann, Daniel, Jackson, Mark G., Adshead, Peter, Amblard, Alexandre, Ashoorioon, Amjad, Bartolo, Nicola, ...
We summarize the utility of precise cosmic microwave background (CMB) polarization measurements as probes of the physics of inflation. We focus on the prospects for using CMB measurements to...
Melchiorri, Alessandro, Mena, Olga, Palomares-Ruiz, Sergio, Pascoli, Silvia, Slosar, Anze, Sorel, Michel
Light sterile neutrinos might mix with the active ones and be copiously produced in the early Universe. In the present paper, a detailed multi-flavor analysis of sterile neutrino production is...
De Bernardis, Francesco, Serra, Paolo, Cooray, Asantha, Melchiorri, Alessandro
We use measurements of luminosity-dependent galaxy bias at several different redshifts, SDSS at $z=0.05$, DEEP2 at $z=1$ and LBGs at $z=3.8$, combined with WMAP five-year cosmic microwave background...
Delayed Recombination and Cosmic Parameters (2008)
Galli, Silvia, Bean, Rachel, Melchiorri, Alessandro, Silk, Joseph
Current cosmological constraints from Cosmic Microwave Background (CMB) anisotropies are typically derived assuming a standard recombination scheme, however additional resonance and ionizing...
Impact of Point Source Clustering on Cosmological Parameters with CMB Anisotropies (2008)
Serra, Paolo, Cooray, Asantha, Amblard, Alexandre, Pagano, Luca, Melchiorri, Alessandro
The faint radio point sources that are unresolved in cosmic microwave background (CMB) anisotropy maps are likely to be a biased tracer of the large-scale structure dark matter distribution. While...
Latest inflation model constraints from cosmic microwave background measurements (2008)
Kinney, William H., Kolb, Edward W., Melchiorri, Alessandro, Riotto, Antonio
In this addendum to Phys.Rev. D74 (2006) 023502, we present an update of cosmological constraints on single-field inflation in light of the Wilkinson Microwave Ansiotropy Probe satellite mission...
Trispectrum of 21-cm background anisotropies as a probe of primordial non-Gaussianity (2008)
Cooray, Asantha, Li, Chao, Melchiorri, Alessandro
The 21-cm anisotropies from the neutral hydrogen distribution prior to the era of reionization are a sensitive probe of primordial non-Gaussianity. Unlike the case with cosmic microwave background,...
Hamann, Jan, Hannestad, Steen, Melchiorri, Alessandro, Wong, Yvonne Y. Y.
We explore and compare the performances of two nonlinear correction and scale-dependent biasing models for the extraction of cosmological information from galaxy power spectrum data, especially in...
Anisotropies in the Cosmic Neutrino Background after WMAP 5-year Data (2008)
De Bernardis, Francesco, Pagano, Luca, Serra, Paolo, Melchiorri, Alessandro, Cooray, Asantha
We search for the presence of cosmological neutrino background (CNB) anisotropies in recent WMAP 5-year data using their signature imprinted on modifications to cosmic microwave background (CMB)...
Red density perturbations and inflationary gravitational waves (2008)
Pagano, Luca, Cooray, Asantha, Melchiorri, Alessandro, Kamionkowski, Marc
We study the implications of recent indications from the Wilkinson Microwave Anisotropy Probe (WMAP) and other cosmological data for a red spectrum of primordial density perturbations for the...
Cosmic Microwave Weak lensing data as a test for the dark universe (2008)
Calabrese, Erminia, Slosar, Anze, Melchiorri, Alessandro, Smoot, George F., Zahn, Oliver
Combined analyses of WMAP 3-year and ACBAR Cosmic Microwave Anisotropies angular power spectra have presented evidence for gravitational lensing >3 sigma level. This signal could provide a relevant...
Is Cosmology Compatible with Blue Gravity Waves ? (2008)
Camerini, Roberta, Durrer, Ruth, Melchiorri, Alessandro, Riotto, Antonio
A primordial gravitational wave background with positive(blue) spectral index is expected in several non-standard inflationary cosmologies where the stress-energy tensor violates the null energy...
Is Cosmology Compatible with Blue Gravity Waves ? (2008)
Camerini, Roberta, Durrer, Ruth, Melchiorri, Alessandro, Riotto, Antonio
A primordial gravitational wave background with positive(blue) spectral index is expected in several non-standard inflationary cosmologies where the stress-energy tensor violates the null energy...
Large Scale Structure as a Probe of Gravitational Slip (2008)
Daniel, Scott F., Caldwell, Robert R., Cooray, Asantha, Melchiorri, Alessandro
A new time-dependent, scale-independent parameter, \varpi, is employed in a phenomenological model of the deviation from General Relativity in which the Newtonian and longitudinal gravitational...
The trispectrum of 21-cm background anisotropies as a probe of primordial non-Gaussianity (2008)
Cooray, Asantha, Li, Chao, Melchiorri, Alessandro
The 21-cm anisotropies from the neutral hydrogen distribution prior to the era of reionization is a sensitive probe of primordial non-Gaussianity. Unlike the case with cosmic microwave background,...
Hamann, Jan, Hannestad, Steen, Melchiorri, Alessandro, Wong, Yvonne Y. Y.
We explore and compare the performances of two nonlinear correction and scale-dependent biasing models for the extraction of cosmological information from galaxy power spectrum data, especially in...
Black hole formation and slow-roll inflation (2007)
Kohri, Kazunori, Lyth, David H, Melchiorri, Alessandro
Black hole formation may occur if the spectrum of the curvature perturbation \zeta increases strongly as the scale decreases. As no such increase is observed on cosmological scales, black hole...
Black hole formation and slow-roll inflation (2007)
Kohri, Kazunori, Lyth, David H., Melchiorri, Alessandro
Black hole formation may occur if the spectrum of the curvature perturbation \zeta increases strongly as the scale decreases. As no such increase is observed on cosmological scales, black hole...
Testing Cosmology with Cosmic Sound Waves (2007)
Corasaniti, Pier Stefano, Melchiorri, Alessandro
WMAP observations have accurately determined the position of the first two peaks and dips in the CMB temperature power spectrum. These encode information on the ratio of the distance to the last...
Testing Cosmology with Cosmic Sound Waves (2007)
Corasaniti, Pier Stefano, Melchiorri, Alessandro
WMAP observations have accurately determined the position of the first two peaks and dips in the CMB temperature power spectrum. These encode information on the ratio of the distance to the last...
The Cosmic Neutrino Background and the Age of the Universe (2007)
De Bernardis, Francesco, Melchiorri, Alessandro, Verde, Licia, Jimenez, Raul
We discuss the cosmological degeneracy between the age of the Universe, the Hubble parameter and the effective number of relativistic particles N_eff. We show that independent determinations of the...
Red Density Perturbations and Inflationary Gravitational Waves (2007)
Pagano, Luca, Cooray, Asantha, Melchiorri, Alessandro, Kamionkowski, Marc
We study the implications of recent indications for a red spectrum of primordial density perturbations for the detection of inflationary gravitational waves (IGWs) with forthcoming cosmic microwave...
Red Density Perturbations and Inflationary Gravitational Waves (2007)
Pagano, Luca, Cooray, Asantha, Melchiorri, Alessandro, Kamionkowski, Marc
We study the implications of recent indications for a red spectrum of primordial density perturbations for the detection of inflationary gravitational waves (IGWs) with forthcoming cosmic microwave...
When Did Cosmic Acceleration Start ? (2007)
Melchiorri, Alessandro, Pagano, Luca, Pandolfi, Stefania
A precise determination, and comparison, of the epoch of the onset of cosmic acceleration, at redshift z_acc, and of dark energy domination, at z_eq, provides an interesting measure with which to...
An improved cosmological bound on the thermal axion mass (2007)
Melchiorri, Alessandro, Mena, Olga, Slosar, Anze
Relic thermal axions could play the role of an extra hot dark matter component in cosmological structure formation theories. By combining the most recent observational data we improve previous...
Constraints on a New Post-General Relativity Cosmological Parameter (2007)
Caldwell, Robert, Cooray, Asantha, Melchiorri, Alessandro
A new cosmological variable is introduced which characterizes the degree of departure from Einstein's General Relativity (GR) with a cosmological constant. The new parameter, \varpi, is the...
New bounds on millicharged particles from cosmology (2007)
Melchiorri, Alessandro, Polosa, Antonello, Strumia, Alessandro
Particles with millicharge q and sub-eV mass can be produced in photon-photon collisions, distorting the energy spectrum of the Cosmic Microwave Background. We derive the conservative bound q < 10^-7...
Massive neutrinos and dark energy (2007)
Serra, Paolo, Bean, Rachel, De La Macorra, Axel, Melchiorri, Alessandro
We consider the impact of the Heidelberg-Moscow claim for a detection of neutrino mass on the determination of the dark energy equation of state. By combining the Heidelberg-Moscow result with the...
Probing Neutrino low energy and mass scales (2007)
Cremonesi, Oliviero, Melchiorri, Alessandro
Low energy neutrino processes are ideal probes for new Physics beyond the Standard Model. Cosmological observations and rare nuclear processes can test neutrino mass scales and give definite answers...
Exploring the Dark Energy Redshift Desert with the Sandage-Loeb Test (2007)
Corasaniti, Pier-Stefano, Huterer, Dragan, Melchiorri, Alessandro
We study the prospects for constraining dark energy at very high redshift with the Sandage-Loeb (SL) test - a measurement of the evolution of cosmic redshift obtained by taking quasar spectra at...
New Constraints on Oscillations in the Primordial Spectrum of Inflationary Perturbations (2007)
Hamann, Jan, Covi, Laura, Melchiorri, Alessandro, Slosar, Anze
We revisit the problem of constraining steps in the inflationary potential with cosmological data. We argue that a step in the inflationary potential produces qualitatively similar oscillations in...
Bayesian Evidence for a Cosmological Constant using new High-Redshift Supernovae Data (2007)
Serra, Paolo, Heavens, Alan, Melchiorri, Alessandro
We carry out a Bayesian model selection analysis of different dark energy parametrizations using the recent luminosity distance data of high redshift supernovae from Riess et al. 2007 and from the...
Cosmological constraints in the presence of ionizing and resonance radiation at recombination (2007)
Bean, Rachel, Melchiorri, Alessandro, Silk, Joe
With the recent measurement of full sky cosmic microwave background polarization from WMAP, key cosmological degeneracies have been broken, allowing tighter constraints to be placed on cosmological...
Mangano, Gianpiero, Melchiorri, Alessandro, Mena, Olga, Miele, Gennaro, Slosar, Anze
We discuss the present bounds on the relativistic energy density in the Universe parameterized in terms of the effective number of neutrinos N using the most recent cosmological data on Cosmic...
Friedman, Brett C., Cooray, Asantha, Melchiorri, Alessandro
In addition to density perturbations, inflationary models of the early universe generally predict a stochastic background of gravitational waves or tensor fluctuations. By making use of the...
The impact of neutrino masses on the determination of dark energy properties (2006)
De La Macorra, Axel, Melchiorri, Alessandro, Serra, Paolo, Bean, Rachel
Recently, the Heidelberg-Moscow double beta decay experiment has claimed a detection for a neutrino mass with high significance. Here we consider the impact of this measurement on the determination...
Cosmological bounds on dark-matter-neutrino interactions (2006)
Mangano, Gianpiero, Melchiorri, Alessandro, Serra, Paolo, Cooray, Asantha, Kamionkowski, Marc
We investigate the cosmological effects of a neutrino interaction with cold dark-matter. We postulate a neutrino that interacts with a "neutrino-interacting dark-matter" (NIDM) particle with an...
Inflation and WMAP three year data: Features have a Future! (2006)
Covi, Laura, Hamann, Jan, Melchiorri, Alessandro, Slosar, Anze, Sorbera, Irene
The new three year WMAP data seem to confirm the presence of non-standard large scale features in the Cosmic Microwave Anisotropies power spectrum. While these features may hint at uncorrected...
Cosmological bounds on dark matter-neutrino interactions (2006)
Mangano, Gianpiero, Melchiorri, Alessandro, Serra, Paolo, Cooray, Asantha, Kamionkowski, Marc
We investigate the cosmological effects of a neutrino interaction with cold dark matter. We postulate a neutrino that interacts with a ``neutrino interacting dark matter'' (NIDM) particle with an...
De Bernardis, Francesco, Giusarma, Elena, Melchiorri, Alessandro
We demonstrate that the recent measurements of the angular diameter distance of 38 cluster of galaxies using Chandra X-ray data and radio observations from the OVRO and BIMA interferometric arrays...
Chaplygin gas in light of recent Integrated Sachs--Wolfe effect data (2006)
Giannantonio, Tommaso, Melchiorri, Alessandro
We investigate the possibility of constraining Chaplygin dark energy models with current Integrated Sachs Wolfe effect data. In the case of a flat universe we found that generalized Chaplygin gas...
Inflation model constraints from the Wilkinson Microwave Anisotropy Probe three-year data (2006)
Kinney, William H., Kolb, Edward W., Melchiorri, Alessandro, Riotto, Antonio
We extract parameters relevant for distinguishing among single-field inflation models from the Wilkinson Microwave Anisotropy Probe (WMAP) three-year data set, and also from WMAP in combination with...
Is cosmology compatible with sterile neutrinos? (2005)
Dodelson, Scott, Melchiorri, Alessandro, Slosar, Anze
By combining data from cosmic microwave background (CMB) experiments (including the recent WMAP third year results), large scale structure (LSS) and Lyman-alpha forest observations, we constrain the...
Cooray, Asantha, Melchiorri, Alessandro
The cross-correlation between cosmic microwave background (CMB) temperature anisotropies and the large scale structure (LSS) traced by the galaxy distribution, or sources at different wavelengths, is...
Did Boomerang hit MOND? (2005)
Slosar, Anze, Melchiorri, Alessandro, Silk, Joseph
Purely baryonic dark matter dominated models like MOND based on modification of Newtonian gravity have been successfully in reproducing some dynamical properties of galaxies. More recently, a...
The running-mass inflation model and WMAP. (2004)
Covi, Laura, Lyth, David H., Melchiorri, Alessandro, Odman, C. J.
We consider the observational constraints on the running-mass inflationary model, and, in particular, on the scale dependence of the spectral index, from the new cosmic microwave background (CMB)...
Indication for Primordial Anisotropies in the Neutrino Background from WMAP and SDSS (2004)
Trotta, Roberto, Melchiorri, Alessandro
We demonstrate that combining Cosmic Microwave Background anisotropy measurements from the 1st year WMAP observations with clustering data from the SLOAN galaxy redshift survey yields an indication...
The running-mass inflation model and WMAP (2004)
Covi, Laura, Lyth, David H., Melchiorri, Alessandro, Odman, Carolina J.
We consider the observational constraints on the running-mass inflationary model, and in particular on the scale-dependence of the spectral index, from the new Cosmic Microwave Background (CMB)...
Capozziello, Salvatore, Melchiorri, Alessandro, Schirone, Alice
We investigate the possibility of a dark energy component that is scaling with epochs. A phenomenological model is introduced whose energy density depends on the redshift in such a way that a smooth...
New Constraints on Dark Energy (2004)
New Cosmic Microwave Background, Galaxy Clustering and Supernovae type Ia data are increasingly constraining the dark energy component of our Universe. While the cosmological constant scenario...
Cosmological parameter estimation with large scale structure and supernovae data (2004)
Odman, Carolina, Hobson, Mike, Lasenby, Anthony, Melchiorri, Alessandro
Most cosmological parameter estimations are based on the same set of observations and are therefore not independent. Here, we test the consistency of parameter estimations using a combination of...
Does the Low CMB Quadrupole Provide a New Cosmic Coincidence Problem ? (2004)
Melchiorri, Alessandro, Mersini-Houghton, Laura
We point out that the recent WMAP findings of a suppressed large scale power in the Cosmic Microwave Background anisotropy power spectrum, if of cosmological origin, make the case for a new cosmic...
Are Domain Walls ruled out ? (2004)
Conversi, Luca, Melchiorri, Alessandro, Mersini, Laura, Silk, Joseph
Recent analysis of the combined data of cosmic microwave background, galaxy clustering and supernovae type Ia observations have set strong constraints on the equation of state parameter $w_X$. The...
Cosmological constraints from Microwave Background Anisotropy and Polarization (2003)
The recent high-quality measurements of the Cosmic Microwave Background anisotropies have presented cosmologists with the possibility of studying the large scale properties of our universe with...
Recombining WMAP: constraints on ionizing and resonance radiation at recombination (2003)
Bean, Rachel, Melchiorri, Alessandro, Silk, Joe
We place new constraints on sources of ionizing and resonance radiation at the epoch of the recombination process using the recent CMB temperature and polarization spectra coming from WMAP. We find...
WMAPping inflationary physics (2003)
Kinney, William H., Kolb, Edward W., Melchiorri, Alessandro, Riotto, Antonio
We extract parameters relevant for distinguishing among single-field inflation models from the Wilkinson Microwave Anisotropy Probe (WMAP) data set, and from a combination of the WMAP data and seven...
Current constraints on Cosmological Parameters from Microwave Background Anisotropies (2003)
Melchiorri, Alessandro, Odman, Carolina
We compare the latest observations of Cosmic Microwave Background (CMB) Anisotropies with the theoretical predictions of the standard scenario of structure formation. Assuming a primordial power...
Using bright ellipticals as dark energy cosmic clocks (2003)
Ferreras, Ignacio, Melchiorri, Alessandro, Tocchini-Valentini, Domenico
The age of the Universe has been increasingly constrained by different techniques such as the observations of type Ia supernovae at high redshift or dating the stellar populations of globular...
New constraints on the running-mass inflation model. (2003)
Covi, Laura;, Lyth, David H., Melchiorri, Alessandro
We evaluate new observational constraints on the two-parameter scale-dependent spectral index predicted by the running-mass inflation model by combining the latest cosmic microwave background...
Dark Energy: Is it Q or Lambda ? (2002)
Melchiorri, Alessandro, Odman, Carolina
New observations of Cosmic Microwave Background Anisotropies, Supernovae luminosity distances and Galaxy Clustering are sharpening our knowledge about dark energy. Here we present the latest...
Melchiorri, Alessandro, Bode, Paul, Bahcall, Neta A., Silk, Joseph
We present constraints on several cosmological parameters from a combined analysis of the most recent Cosmic Microwave Background anisotropy data and the Sloan Digital Sky Survey cluster mass...
The State of the Dark Energy Equation of State (2002)
Melchiorri, Alessandro, Mersini, Laura, Odman, Carolina J., Trodden, Mark
By combining data from seven cosmic microwave background experiments (including the latest WMAP results) with large scale structure data, the Hubble parameter measurement from the Hubble Space...
New Constraints on the running-mass inflation model (2002)
Covi, Laura, Lyth, David H., Melchiorri, Alessandro
We evaluate new observational constraints on the two-parameter scale-dependent spectral index predicted by the running-mass inflation model by combining the latest Cosmic Microwave Background (CMB)...
Melchiorri, Alessandro, Odman, Carolina
One of the major predictions of inflation is the existence of a stochastic background of cosmological gravitational waves (GW). These gravitational waves can induce significant temperature...
Cooray, Asantha, Melchiorri, Alessandro
The advent of high-resolution cosmic microwave background (CMB) experiments now allows studies on the temperature fluctuations at scales corresponding to a few arcminutes and below. Though the...
Constraining the shape of the CMB: a Peak-by-Peak analysis (2002)
Odman, Carolina J., Melchiorri, Alessandro, Hobson, Michael P., Lasenby, Anthony N.
The recent measurements of the power spectrum of Cosmic Microwave Background anisotropies are consistent with the simplest inflationary scenario and big bang nucleosynthesis constraints. However,...
Is the Cosmic Microwave Background Circularly Polarized? (2002)
Cooray, Asantha, Melchiorri, Alessandro, Silk, Joseph
The primordial anisotropies of the cosmic microwave background (CMB) are linearly polarized via Compton-scattering. The Faraday conversion process during the propagation of polarized CMB photons...
Cosmology Rounding the Cape (2002)
A survey is made of the present observational status on cosmological parameters from microwave background anisotropies. I then move to some non-standard aspect of parameter extraction like...
Small Angular Scale CMB Anisotropies from CBI and BIMA: Early Universe or Local structures ? (2002)
Cooray, Asantha, Melchiorri, Alessandro
The advent of high resolution cosmic microwave background (CMB) experiments now allows studies on the temperature fluctuations at scales corresponding to few arcminutes and below. Though the reported...
CMB and Cosmological Parameters: Current Status and Prospects (2002)
The last years have been an exciting period for the field of the Cosmic Microwave Background (CMB) research. With recent CMB balloon-borne and ground-based experiments we are entering a new era of...
Multiple Peaks in the CMB (2002)
Recent measurements of the Cosmic Microwave Background Anisotropy have provided evidence for the presence of oscillations in the angular power spectrum. These oscillations are a wonderful...
Constraining the Dark Universe (2002)
Bean, Rachel, Hansen, Steen H., Melchiorri, Alessandro
We combine complementary datasets to constrain dark energy. Using standard Big Bang Nucleosynthesis and the observed abundances of primordial nuclides to put constraints on $\Omega_Q$ at temperatures...
Current constraints on the dark energy equation of state (2001)
Bean, Rachel, Melchiorri, Alessandro
We combine complementary datasets from Cosmic Microwave Background (CMB) anisotropy measurements, high redshift supernovae (SN-Ia) observations and data from local cluster abundances and galaxy...
Early-universe constraints on a Primordial Scaling Field (2001)
Bean, Rachel, Hansen, Steen H., Melchiorri, Alessandro
In the past years 'quintessence' models have been considered which can produce the accelerated expansion in the universe suggested by recent astronomical observations. One of the key differences...
CMB Constraints on a Baryonic Dark Matter-Dominated Universe (2001)
Griffiths, Louise M, Melchiorri, Alessandro, Silk, Joseph
In recent years, upper limits on the cosmic microwave background (CMB) anisotropies combined with predictions made by theories of galaxy formation, have been extremely powerful in ruling out purely...
CMB anisotropies in pre-big bang cosmology (2000)
Vernizzi, Filippo, Melchiorri, Alessandro, Durrer, Ruth
We present an alternative scenario for cosmic structure formation where initial fluctuations are due to Kalb-Ramond axions produced during a pre-big bang phase of inflation. We investigate whether...
From Anisotropy to Omega (2000)
Melchiorri, Alessandro, Griffiths, Louise M.
Following the recent measurement of the acoustic peak by the BOOMERanG and MAXIMA experiments in the CMB anisotropy angular power spectrum, many analyses have found that the geometry of the Universe...
New Constraints on inflation from the Cosmic Microwave Background (2000)
Kinney, William H., Melchiorri, Alessandro, Riotto, Antonio
The recent data from the Boomerang and MAXIMA-1 balloon flights have marked the beginning of the precision era of Cosmic Microwave Background anisotropy (CMB) measurements. We investigate the...
Cosmic Microwave Background Anisotropies from Global Texture (1999)
Durrer, Ruth, Kunz, Martin, Melchiorri, Alessandro
We investigate the global texture model of structure formation in cosmogonies with non-zero cosmological constant for different values of the Hubble parameter. We find that the absence of significant...
Cosmic Microwave Background Anisotropies from Scaling Seeds: Global Defect Models (1998)
Durrer, Ruth, Kunz, Martin, Melchiorri, Alessandro
We investigate the global texture model of structure formation in cosmogonies with non-zero cosmological constant for different values of the Hubble parameter. We find that the absence of significant...
Polarization of the Microwave Background: theoretical framework (1996)
Melchiorri, Alessandro, Vittorio, Nicola
We present a brief review of the polarization properties of the cosmic microwave background in dark matter models for structure formation. Quite independently of the model parameters, the...
CMB anisotropy at degree angular scales and the thermal history of the Universe (1996)
De Bernardis, Paolo, Balbi, Amedeo, De Gasperis, Giancarlo, Melchiorri, Alessandro, Vittorio, Nicola
We study the anisotropy of the cosmic microwave background (CMB) in cold and mixed dark matter (CDM and MDM) models, with non scale-invariant primordial power spectra (i.e. $n \neq 1$) and a late,...