145 research outputs found
Correlations in the (Sub)millimeter Background from ACT × BLAST
We present measurements of the auto- and cross-frequency correlation power spectra of the cosmic (sub)millimeter background at 250, 350, and 500 μm (1200, 860, and 600 GHz) from observations made with the Balloon-borne Large Aperture Submillimeter Telescope (BLAST); and at 1380 and 2030 μm (218 and 148 GHz) from observations made with the Atacama Cosmology Telescope (ACT). The overlapping observations cover 8.6 deg^2 in an area relatively free of Galactic dust near the south ecliptic pole. The ACT bands are sensitive to radiation from the cosmic microwave background, to the Sunyaev-Zel'dovich effect from galaxy clusters, and to emission by radio and dusty star-forming galaxies (DSFGs), while the dominant contribution to the BLAST bands is from DSFGs. We confirm and extend the BLAST analysis of clustering with an independent pipeline and also detect correlations between the ACT and BLAST maps at over 25σ significance, which we interpret as a detection of the DSFGs in the ACT maps. In addition to a Poisson component in the cross-frequency power spectra, we detect a clustered signal at 4σ, and using a model for the DSFG evolution and number counts, we successfully fit all of our spectra with a linear clustering model and a bias that depends only on redshift and not on scale. Finally, the data are compared to, and generally agree with, phenomenological models for the DSFG population. This study demonstrates the constraining power of the cross-frequency correlation technique to constrain models for the DSFGs. Similar analyses with more data will impose tight constraints on future models
Bipolar Harmonic encoding of CMB correlation patterns
Deviations from statistical isotropy can be modeled in various ways, for
instance, anisotropic cosmological models (Bianchi models), compact topologies
and presence of primordial magnetic field. Signature of anisotropy manifests
itself in CMB correlation patterns. Here we explore the symmetries of the
correlation function and its implications on the observable measures
constructed within the Bipolar harmonic formalism for these variety of models.
Different quantifiers within the Bipolar harmonic representation are used to
distinguish between plausible models of breakdown of statistical isotropy and
as a spectroscopic tool for discriminating between distinct cosmic topology.Comment: Revised version, accepted for publication in Phys. Rev.
LongFin: A Multimodal Document Understanding Model for Long Financial Domain Documents
Document AI is a growing research field that focuses on the comprehension and
extraction of information from scanned and digital documents to make everyday
business operations more efficient. Numerous downstream tasks and datasets have
been introduced to facilitate the training of AI models capable of parsing and
extracting information from various document types such as receipts and scanned
forms. Despite these advancements, both existing datasets and models fail to
address critical challenges that arise in industrial contexts. Existing
datasets primarily comprise short documents consisting of a single page, while
existing models are constrained by a limited maximum length, often set at 512
tokens. Consequently, the practical application of these methods in financial
services, where documents can span multiple pages, is severely impeded. To
overcome these challenges, we introduce LongFin, a multimodal document AI model
capable of encoding up to 4K tokens. We also propose the LongForms dataset, a
comprehensive financial dataset that encapsulates several industrial challenges
in financial documents. Through an extensive evaluation, we demonstrate the
effectiveness of the LongFin model on the LongForms dataset, surpassing the
performance of existing public models while maintaining comparable results on
existing single-page benchmarks.Comment: Accepted at AAAI 2024 Workshop on AI in Finance for Social Impac
Statistical Isotropy of CMB Polarization Maps
We formulate statistical isotropy of CMB anisotropy maps in its most general
form. We also present a fast and orientation independent statistical method to
determine deviations from statistical isotropy in CMB polarization maps.
Importance of having statistical tests of departures from SI for CMB
polarization maps lies not only in interesting theoretical motivations but also
in testing cleaned CMB polarization maps for observational artifacts such as
residuals from polarized foreground emission. We propose a generalization of
the Bipolar Power Spectrum (BiPS) to polarization maps. Application to the
observed CMB polarization maps will be soon possible after the release of WMAP
three year data. As a demonstration we show that for E-polarization this test
can detect breakdown of statistical isotropy due to polarized synchrotron
foreground.Comment: 6 pages, 2 figures, Conclusions & results unchanged; Extension to
cutsky included (discussion & references added); Matches version accepted to
Phys. Rev. D Rapid Com
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