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We present a sample of 18 optically-selected and X-ray detected spatially offset active galactic nuclei (AGN) from the Sloan Digital Sky Survey (SDSS). In 9 systems, the X-ray AGN is spatially offset from the galactic stellar core that is…

Astrophysics of Galaxies · Physics 2016-09-28 R. Scott Barrows , Julia M. Comerford , Jenny E. Greene , David Pooley

WFIRST will conduct a coronagraphic program of characterizing the atmospheres of planets around bright nearby stars. When observed with the WFIRST Wide Field Camera, these stars will saturate the detector and produce very strong diffraction…

Instrumentation and Methods for Astrophysics · Physics 2018-02-08 Peter Melchior , David Spergel , Arianna Lanz

NASA's return to the Moon presents unparalleled opportunities to advance high-impact scientific capabilities. At the cutting edge of these possibilities are extremely high-resolution interferometric observations at visible and ultraviolet…

We investigate a sample of 2293 ICRF2 extragalactic radio-loud sources with accurate positions determined by VLBI, mostly active galactic nuclei (AGN) and quasars, which are cross-matched with optical sources in the first Gaia release (Gaia…

The application of artificial neural networks (ANNs) for the estimation of HI gas mass fraction (\fgas) is investigated, based on a sample of 13,674 galaxies in the Sloan Digital Sky Survey (SDSS) with HI detections or upper limits from the…

Astrophysics of Galaxies · Physics 2016-12-07 Hossen Teimoorinia , Sara L. Ellison , David R. Patton

GRAVITY is the second generation VLT Interferometer (VLTI) instrument for high-precision narrow-angle astrometry and phase-referenced interferometric imaging. The laser metrology system of GRAVITY is at the heart of its astrometric mode,…

Reliable GNSS positioning in complex environments remains a critical challenge due to non-line-of-sight (NLOS) propagation, multipath effects, and frequent signal blockages. These effects can easily introduce large outliers into the raw…

Robotics · Computer Science 2025-10-02 Baoshan Song , Penggao Yan , Xiao Xia , Yihan Zhong , Weisong Wen , Li-Ta Hsu

The third Fermi-LAT catalog (3FGL) presented the data of the first four years of observations from the Fermi Gamma-ray Space Telescope mission. There are 3034 sources, 1010 of which still remain unidentified. Identifying and classifying…

We perform long-term ($\approx 15$ yr, observed-frame) X-ray variability analyses of the 68 brightest radio-quiet active galactic nuclei (AGNs) in the 6 Ms $Chandra$ Deep Field-South (CDF-S) survey; the majority are in the redshift range of…

High Energy Astrophysical Phenomena · Physics 2016-11-09 G. Yang , W. Brandt , B. Luo , Y. Xue , F. Bauer , M. Sun , S. Kim , S. Schulze , X. Zheng , M. Paolillo , O. Shemmer , T. Liu , D. Schneider , C. Vignali , F. Vito , J. -X. Wang

We present a series of new, publicly available mock catalogs of X-ray selected active galactic nuclei (AGNs), non-active galaxies, and clusters of galaxies. They are based on up-to-date observational results on the demographic of…

We present the analysis and results of a spectroscopic follow-up program of a mass-selected sample of six galaxies at 3 < z < 4 using data from Keck-NIRSPEC and VLT-Xshooter. We confirm the z > 3 redshifts for half of the sample through the…

We perform a Very Large Telescope FOcal Reducer and low dispersion Spectrograph 2 (VLT/FORS2) narrowband imaging search around 5 star-forming galaxies at redshift z=0.67-0.69 in the Great Observatories Origins Deep Survey South (GOODS-S)…

Infrared interferometry is a new frontier for precision ground based observing, with new instrumentation achieving milliarcsecond (mas) spatial resolutions for faint sources, along with astrometry on the order of 10 microarcseconds. This…

Fringe tracking in interferometers is typically analyzed with the implicit assumption that there is a single phase associated with each telescope in the array. If the telescopes have apertures significantly larger than r0 and only partial…

Astrophysics · Physics 2009-11-13 David F. Buscher , John S. Young , Fabien Baron , Christopher A. Haniff

The MRS is one of the four observing modes of JWST/MIRI. Using JWST in-flight data of unresolved (point) sources, we can derive the MRS absolute spectral response function (ASRF) starting from raw data. Spectral fringing plays a critical…

Radiative transfer calculations have predicted intensity enhancements for optically thick emission lines, as opposed to the normal intensity reductions, for astrophysical plasmas under certain conditions. In particular, the results are…

Solar and Stellar Astrophysics · Physics 2015-05-30 F. P. Keenan , D. J. Christian , S. J. Rose , M. Mathioudakis

Using blazar light curves from the optical All-Sky Automated Survey for Supernovae (ASAS-SN) and the $\gamma$-ray \textit{Fermi}-LAT telescope, we performed the most extensive statistical correlation study between both bands, using a sample…

High Energy Astrophysical Phenomena · Physics 2023-01-18 T. de Jaeger , B. J. Shappee , C. S. Kochanek , J. T. Hinkle , S. Garrappa , I. Liodakis , A. Franckowiak , K. Z. Stanek , J. F. Beacom , J. L. Prieto

We have carried out a deep (21.5<R<23.9) systematic survey of galaxies selected from SWIRE using GMOS to target X-ray sources, AGN and galaxies with photometric redshifts greater than 1. We have obtained a total of 198 redshifts, of which…

Astrophysics · Physics 2007-05-23 M. Trichas , M. Rowan-Robinson , I. Waddington , T. S. R Babbedge

To evaluate a potential usually one analyzes trajectories of test particles. For the Galactic Center case astronomers use bright stars or photons, so there are two basic observational techniques to investigate a gravitational potential,…

General Relativity and Quantum Cosmology · Physics 2019-01-25 Alexander Zakharov

We illustrate the extraordinary potential of the (far-IR) Origins Survey Spectrometer (OSS) on board the Origins Space Telescope (OST) to address a variety of open issues on the co-evolution of galaxies and AGNs. We present predictions for…