Detection of Cosmic Magnification with the Sloan Digital Sky Survey

Scranton, Ryan; Ménard, Brice; Richards, Gordon T.; Nichol, R. C.; Myers, Adam D.; Jain, Bhuvnesh; Gray, Alexander; Bartelmann, Matthias; Brunner, Róbert; Connolly, Andrew J.; Gunn, James E.; Sheth, Ravi K.; Bahcall, Neta A.; Brinkman, John; Loveday, Jon; Schneider, Donald P.; Thakar, Aniruddha R.; York, Donald G.

doi:10.1086/431358

Cited by 244 publications

(304 citation statements)

References 67 publications

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“…The average magnification effect induced by galaxies was detected by Scranton et al (2005). These authors report an average magnification excess of order one percent for impact parameters of about 50 kpc.…”

Section: Dust and Amplification Biasesmentioning

confidence: 91%

Incidence of Mg ii absorbers towards blazars and the GRB/QSO puzzle

Bergeron

Boissé

Ménard

2010

A&A

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In order to investigate the origin of the excess of strong Mg ii systems towards GRB afterglows as compared to QSO sightlines, we have measured the incidence of Mg ii absorbers towards a third class of objects: the blazars. This class includes the BL Lac object population for which a tentative excess of Mg ii systems had already been reported. We observed with FORS1 at the ESO-VLT 42 blazars with an emission redshift 0.8 < z em < 1.9, to which we added the three high z northern objects belonging to the 1 Jy BL Lac sample. We detect 32 Mg ii absorbers in the redshift range 0.35-1.45, leading to an excess in the incidence of Mg ii absorbers compared to that measured towards QSOs by a factor ∼2, detected at 3σ. The amplitude of the effect is similar to that found along GRB sightlines. Our analysis provides a new piece of evidence that the observed incidence of Mg ii absorbers might depend on the type of background source. In front of blazars, the excess is apparent for both "strong" (w r (2796) > 1.0 Å) and weaker (0.3 < w r (2796) < 1.0 Å) Mg ii systems. The dependence on velocity separation with respect to the background blazars indicates, at the ∼1.5σ level, a potential excess for β ≡ v/c ∼ 0.1. We show that biases involving dust extinction or gravitational amplification are not likely to notably affect the incidence of Mg ii systems towards blazars. Finally we discuss the physical conditions required for these absorbers to be gas entrained by the powerful blazar jets. More realistic numerical modelling of jet-ambient gas interaction is required to reach any firm conclusions as well as repeat observations at high spectral resolution of strong Mg ii absorbers towards blazars in both high and low states.

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Section: Dust and Amplification Biasesmentioning

confidence: 91%

Incidence of Mg ii absorbers towards blazars and the GRB/QSO puzzle

Bergeron

Boissé

Ménard

2010

A&A

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“…Such cross-correlations have been measured using samples of distant quasars magnified by low redshift galaxies (e.g., Benitez & Martinez- Gonzalez (1997); Gaztañaga (2003); Myers et al (2005); Scranton et al (2005)), that can be used to put constraints on the galaxy-mass power spectrum (Jain et al 2003). For a magnitude limited survey, the cumulative number of galaxies above a flux limit f scales as N0(> f ) ∼ Af α , where A is the area of the survey, and α is the power-law slope of the background number counts.…”

Section: Magnification From Galaxy Cross-correlationsmentioning

confidence: 99%

The MICE Grand Challenge light-cone simulation – III. Galaxy lensing mocks from all-sky lensing maps

Fosalba¹,

Gaztañaga²,

Castander³

et al. 2014

Monthly Notices of the Royal Astronomical Society

170

142

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In paper I of this series , we presented a new N-body lightcone simulation from the MICE collaboration, the MICE Grand Challenge (MICE-GC), containing about 70 billion dark-matter particles in a (3 h −1 Gpc) 3 comoving volume, from which we built halo and galaxy catalogues using a Halo Occupation Distribution and Halo Abundance Matching technique, as presented in the companion Paper II . Given its large volume and fine mass resolution, the MICE-GC simulation also allows an accurate modeling of the lensing observables from upcoming wide and deep galaxy surveys. In the last paper of this series (Paper III), we describe the construction of all-sky lensing maps, following the "Onion Universe" approach (Fosalba et al. 2008), and discuss their properties in the lightcone up to z = 1.4 with sub-arcmin spatial resolution. By comparing the convergence power spectrum in the MICE-GC to lower mass-resolution (i.e., particle mass ∼ 10 11 h −1 M ) simulations, we find that resolution effects are at the 5% level for multipoles ∼ 10 3 and 20 % for ∼ 10 4 . Resolution effects have a much lower impact on our simulation, as shown by comparing the MICE-GC to recent numerical fits by Takahashi et al 2012. We use the all-sky lensing maps to model galaxy lensing properties, such as the convergence, shear, and lensed magnitudes and positions, and validate them thoroughly using galaxy shear auto and cross-correlations in harmonic and configuration space. Our results show that the galaxy lensing mocks here presented can be used to accurately model lensing observables down to arc-minute scales. Accompanying this series of papers, we make a first public data release of the MICE-GC galaxy mock, the MICECAT v1.0, through a dedicated web-portal for the MICE simulations: http://cosmohub.pic.es, to help developing and exploiting the new generation of astronomical surveys.

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“…Moreover, the intrinsic clustering of galaxies gives large fluctuations in the number density that greatly exceed those due to lensing effects. For these reasons, magnification has lagged behind shear as a cosmological probe, and the cosmic magnification signal was not seen until Scranton et al (2005) measured it using cross-correlation of foreground galaxies and background quasars. Ménard et al (2010) provide a more detailed analysis, using color information to simultaneously detect lensing magnification and reddening of quasars by dust correlated with intervening galaxies.…”

mentioning

confidence: 99%

Observational probes of cosmic acceleration

et al. 2013

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The accelerating expansion of the universe is the most surprising cosmological discovery in many decades, implying that the universe is dominated by some form of "dark energy" with exotic physical properties, or that Einstein's theory of gravity breaks down on cosmological scales. The profound implications of cosmic acceleration have inspired ambitious efforts to understand its origin, with experiments that aim to measure the history of expansion and growth of structure with percent-level precision or higher. We review in detail the four most well established methods for making such measurements: Type Ia supernovae, baryon acoustic oscillations (BAO), weak gravitational lensing, and the abundance of galaxy clusters. We pay particular attention to the systematic uncertainties in these techniques and to strategies for controlling them at the level needed to exploit "Stage IV" dark energy facilities such as BigBOSS, LSST, Euclid, and WFIRST. We briefly review a number of other approaches including redshift-space distortions, the Alcock-Paczynski effect, and direct measurements of the Hubble constant H 0 . We present extensive forecasts for constraints on the dark energy equation of state and parameterized deviations from General Relativity, achievable with Stage III and Stage IV experimental programs that incorporate supernovae, BAO, weak lensing, and cosmic microwave background data. We also show the level of precision required for clusters or other methods to provide constraints competitive with those of these fiducial programs. We emphasize the value of a balanced program that employs several of the most powerful methods in combination, both to cross-check systematic uncertainties and to take advantage of complementary information. Surveys to probe cosmic acceleration produce data sets that support a wide range of scientific investigations, and they continue the longstanding astronomical tradition of mapping the universe in ever greater detail over ever larger scales.

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Detection of Cosmic Magnification with the Sloan Digital Sky Survey

Cited by 244 publications

References 67 publications

Incidence of Mg ii absorbers towards blazars and the GRB/QSO puzzle

Incidence of Mg ii absorbers towards blazars and the GRB/QSO puzzle

The MICE Grand Challenge light-cone simulation – III. Galaxy lensing mocks from all-sky lensing maps

Observational probes of cosmic acceleration

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