Results 21 to 30 of about 12,959,304 (254)

The Statistical Uncertainties on X-Ray Flux and Spectral Parameters from Chandra ACIS-I Observations of Faint Sources: Application to the Cygnus OB2 Association

open access: yesThe Astrophysical Journal Supplement Series, 2023
We investigate the uncertainties of fitted X-ray model parameters and fluxes for relatively faint Chandra ACIS-I source spectra. Monte Carlo (MC) simulations are employed to construct a large set of 150,000 fake X-ray spectra in the low photon count ...
J. F. Albacete-Colombo   +5 more
doaj   +1 more source

The Benefits of Using XML Technologies in Astronomical Data Retrieval and Interpretation [PDF]

open access: yes, 2016
This paper describes a solution found during recent research that could provide improvements in the efficiency, reliability and cost of retrieving stored astronomical data.
Doicu, Adrian   +67 more
core   +1 more source

Fast Globally Optimal Catalog Matching using MIQCP

open access: yesThe Astronomical Journal, 2023
We propose a novel exact method to solve the probabilistic catalog matching problem faster than previously possible. Our new approach uses mixed integer programming and introduces quadratic constraints to shrink the problem by multiple orders of ...
Jacob Feitelberg   +2 more
doaj   +1 more source

The NASA Astrophysics Data System: Free Access to the Astronomical Literature On-Line and through Email [PDF]

open access: yes, 2001
The Astrophysics Data System (ADS) provides access to the astronomical literature through the World Wide Web. It is a NASA funded project and access to all the ADS services is free to everybody world-wide.
Kurtz, Michael J.   +4 more
core   +1 more source

Astronomical observations: a guide for allied researchers

open access: yesThe Open Journal of Astrophysics, 2019
Observational astrophysics uses sophisticated technology to collect and measure electromagnetic and other radiation from beyond the Earth. Modern observatories produce large, complex datasets and extracting the maximum possible information from them ...
Pauline Barmby
doaj   +1 more source

What’s the Difference? The Potential for Convolutional Neural Networks for Transient Detection without Template Subtraction

open access: yesThe Astronomical Journal, 2023
We present a study of the potential for convolutional neural networks (CNNs) to enable separation of astrophysical transients from image artifacts, a task known as “real–bogus” classification, without requiring a template-subtracted (or difference) image,
Tatiana Acero-Cuellar   +5 more
doaj   +1 more source

Secondary Standards in the UKIRT Faint Standard Fields

open access: yesThe Astrophysical Journal Supplement Series
We present precise J - and K -band photometric measurements for 128 near-infrared (NIR) secondary standard stars, located in the 19 United Kingdom Infrared Telescope/Maunakea Observatories (UKIRT/MKO) primary faint standard fields.
Marek Górski   +10 more
doaj   +1 more source

Neurochemical Endpoints to Inform Early‐Stage Trials of Spinocerebellar Ataxia 2 and 3 in a Multisite Setting

open access: yesAnnals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Objective Neurochemical levels measured by brain MR spectroscopy (MRS) have been proposed as endpoints for clinical trials in early‐stage spinocerebellar ataxia (SCA) trials. We tested their trial‐readiness by quantifying neurochemicals in three affected brain regions in early‐stage cohorts of SCA2 and SCA3, examining their reproducibility in ...
James M. Joers   +19 more
wiley   +1 more source

Mutual Impedance Properties in a Lossy Array Antenna

open access: yesInternational Journal of Antennas and Propagation, 2019
The impedance matrix of an arbitrary multiport array antenna with Ohmic losses was studied. It was assumed that the partial current distributions in the array, corresponding to the alternate exciting one of its terminals while the other ones are open ...
Peter L. Tokarsky
doaj   +1 more source

IceCat-1: The IceCube Event Catalog of Alert Tracks

open access: yesThe Astrophysical Journal Supplement Series, 2023
We present a catalog of likely astrophysical neutrino track-like events from the IceCube Neutrino Observatory. IceCube began reporting likely astrophysical neutrinos in 2016, and this system was updated in 2019. The catalog presented here includes events
R. Abbasi   +393 more
doaj   +1 more source

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