Dipole Anisotropy in the COBE Differential Microwave Radiometers First-Year Sky Maps

Kogut, A.; Lineweaver, Charles H.; Smoot, G. F.; Bennett, C. L.; Banday, A. J.; Boggess, N. W.; Cheng, E. S.; Amici, Giovanni De; Fixsen, D. J.; Hinshaw, G.; Jackson, P. D.; Janssen, M. A.; Keegstra, P.; Loewenstein, K.; Lubin, P. M.; Mather, John C.; Tenorio, Luis; Weiss, R.; Wilkinson, D. T.; Wright, E. L.

doi:10.1086/173453

Cited by 375 publications

(346 citation statements)

References 24 publications

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“…The typical time scale of caustic-crossing events is determined by the relative velocity v of the source with respect to the caustic's pattern and the observer (Kayser et al 1986). Assuming that the velocities of the source and the lens are of the same order as the velocity of the Sun with regard to the cosmic microwave background reference frame v 300 km s −1 (Kogut et al 1993), one could find that the strong magnification events that are related to the crossing of the source by the microlensing caustics last for ∆t γ = R γ,proj /v rel 100 R γ,proj 3 × 10 14 cm v rel 300 km s −1…”

Section: Qualitative Estimates Of the Microlensing Constraint On The mentioning

confidence: 99%

Microlensingconstraintson the size of the gamma-ray emission region in blazar B0218+357

Vovk

Neronov

2016

A&A

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Context.Observations of the effect of microlensing in gravitationally lensed quasars could potentially be used to study the structure of the source on very small distance scales -down to the size of the supermassive black hole, that powers the quasar activity. Aims. We search for the microlensing effect in the γ-ray band using the signal from a gravitationally lensed blazar, B0218+357. Methods. We develop a method to deconvolve the contributions from the two images of the source, which allows us to reconstruct the flaring light curve in the γ-ray band. We use this method to study the evolution of the magnification factor ratio between the two images throughout the flaring episodes. We interpret the time variability of the ratio as a signature of the microlensing effect and derive constraints on the physical parameters of the γ-ray source by comparing the observed variability properties of the magnification factor ratio with those derived from numerical simulations of the microlensing caustics networks. Results. We find that the magnification factor ratio experienced a change characteristic for a caustic-crossing microlensing event that occurred during a 100 d flaring period in 2012. It changed again between 2012 and a recent flaring episode in 2014. We use the measurement of the maximal magnification and duration of the caustic-crossing event to derive an estimate of the projected size of the γ-ray emission region in B0218+357, R γ ∼ 10 14 −10 15 cm. This estimate is compatible with a complementary estimate found from the minimal variability time scale. The microlensing/minimal variability time scale measurements of the source size suggest that the γ-ray emission is produced at the base of the blazar jet, in the direct vicinity of the central supermassive black hole.

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Section: Qualitative Estimates Of the Microlensing Constraint On The mentioning

confidence: 99%

Microlensingconstraintson the size of the gamma-ray emission region in blazar B0218+357

Vovk

Neronov

2016

A&A

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“…In addition, we made a secondary calibration through measurements of the CMB dipole, which is known to '1% accuracy from the measurements of the COBE satellite (Kogut et al 1993).…”

Section: Jupiter Calibration and Beam Mappingmentioning

confidence: 99%

The BOOMERANG North America Instrument: A Balloon‐borne Bolometric Radiometer Optimized for Measurements of Cosmic Background Radiation Anisotropies from 0.̊3 to 4o

Bhatia

Bock

Boscaleri³

et al. 2002

ASTROPHYS J SUPPL S

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We describe the BOOMERANG North America instrument, a balloon-borne bolometric radiometer designed to map the cosmic microwave background (CMB) radiation with 0=3 resolution over a significant portion of the sky. This receiver employs new technologies in bolometers, readout electronics, millimeterwave optics and filters, cryogenics, scan, and attitude reconstruction. All these subsystems are described in detail in this paper. The system has been fully calibrated in flight using a variety of techniques, which are described and compared. Using this system, we have obtained a measurement of the first peak in the CMB angular power spectrum in a single, few hour long balloon flight. The instrument described here was a prototype of the BOOMERANG Long Duration Balloon experiment.

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“…Gorski et al 1989;Davis, Strauss & Yahil 1991;Strauss, Cen & Ostriker 1993;Moscardini et al 1994). Three different requirements were imposed to each of these observers: i) its peculiar velocity v is in the range of the observed LG motion, v LG,obs = 627 ± 22 km s −1 (Kogut et al 1993); ii) the local flow around the mock LG is quiet with a small local 'shear', S ≡ |v − v |/|v| < 0.2, where v is the average velocity of a sphere of radius R = 750 km s −1 centred on the LG; iii) the density contrast in the same sphere is in the range −0.2 ≤ δ ≤ 1.0.…”

Section: Sample and Catalogue Constructionmentioning

confidence: 99%

“…The reference frame was built from each LG position imposing that the velocity vector of the central point had the CMB dipole direction (l = 276 ± 3 • , b = 30 ± 3 • ; Kogut et al 1993), with the direction of the remaining axis randomly selected. Next, we constructed our catalogues by collecting, for each of the 704 positions of the observed objects, the closest particle in the simulation and considering the radial component of its velocity with respect to the LG position.…”

Section: Sample and Catalogue Constructionmentioning

confidence: 99%

Velocity fields in non-Gaussian cold dark matter models

Lucchin¹,

Matarrese²,

Messina³

et al. 1995

Monthly Notices of the Royal Astronomical Society

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We analyse the large-scale velocity field obtained by N-body simulations of cold dark matter (CDM) models with non-Gaussian primordial density fluctuations, considering models with both positive and negative primordial skewness in the density fluctuation distribution. We study the velocity probability distribution and calculate the dependence of the bulk flow, one-point velocity dispersion and Cosmic Mach Number on the filtering size. We find that the sign of the primordial skewness of the density field provides poor discriminatory power on the evolved velocity field. All non-Gaussian models here considered tend to have lower velocity dispersion and bulk flow than the standard Gaussian CDM model, while the Cosmic Mach Number turns out to be a poor statistic in characterizing the models. Next, we compare the large-scale velocity field of a composite sample of optically selected galaxies as described by the Local Group properties, bulk flow, velocity correlation function and Cosmic Mach Number, with the velocity field of mock catalogues extracted from the N-body simulations. The comparison does not clearly permit to single out a best model: the standard Gaussian model is however marginally preferred by the maximum likelihood analysis.

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Dipole Anisotropy in the COBE Differential Microwave Radiometers First-Year Sky Maps

Cited by 375 publications

References 24 publications

Microlensingconstraintson the size of the gamma-ray emission region in blazar B0218+357

Microlensingconstraintson the size of the gamma-ray emission region in blazar B0218+357

The BOOMERANG North America Instrument: A Balloon‐borne Bolometric Radiometer Optimized for Measurements of Cosmic Background Radiation Anisotropies from 0.̊3 to 4o

Velocity fields in non-Gaussian cold dark matter models

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