Results 71 to 80 of about 18,849 (212)

Varstrometry for Off-nucleus and Dual Sub-Kpc AGN (VODKA): Long-slit Optical Spectroscopic Follow-up with Gemini/GMOS and Hubble Space Telescope/STIS

The Astrophysical Journal
High spatial and spectral resolution observations are essential for identifying subarcsecond dual and lensed quasars and confirming their redshifts. We present Gemini/Gemini Multi-Object Spectrograph and Hubble Space Telescope/STIS optical spectra for 27
Yu-Ching Chen, Arran C. Gross, Xin Liu, Yue Shen, Nadia L. Zakamska, Hsiang-Chih Hwang, Ming-Yang Zhuang   +6 more
doaj   +1 more source

Discovery of a red quasar with recurrent activity [PDF]

, 2014
We report a new double-double radio quasar, DDRQ, J0746$+$4526 which exhibits two cycles of episodic activity. From radio continuum observations at 607 MHz using the GMRT and 1400 MHz from the FIRST survey we confirm its episodic nature.
Baes, M., Chandola, H. C., Gentile, G., Joshi, R., Nandi, S., Patgiri, M., Roy, R., Saikia, D. J., Singh, M.   +8 more
core   +3 more sources

Localized Energy Absorption through LaB6 Surface Modification of PA12 Enables Enhanced Tensile Performance in Diode Laser PBF‐LB

Chemistry–Methods, Volume 5, Issue 12, November 2025.
LaB6 surface modification of PA12 enables efficient NIR diode laser PBF‐LB processing, with enhanced tensile strength and tailored microstructures achieved at minimal additionaly energy. By reducing the need for high filler content, this approach expands the options and performance levels of advanced industrial‐grade polymer additive manufacturing. The
Nadine Stratmann, Michael Willeke, Simon Leupold, Kateryna Loza, Arne Lüddecke, Arno Kwade, Michael Schmidt, Stephan Barcikowski, Anna Rosa Ziefuss   +8 more
wiley   +1 more source

Deceleration of Relativistic Radio Components and the morphologies of Gigahertz Peaked Spectrum Sources [PDF]

, 1998
A relativistic radio component, which moves in a direction close to the sky plane, will increase in flux density when it decelerates. This effect is the basis for the qualitative model for GPS galaxies we present in this paper, which can explain their ...
de Bruyn, A. G., Miley, G. K., Schilizzi, R. T., Snellen, I. A. G.   +3 more
core   +3 more sources

Constraining Omega_0 With The Angular-Size Redshift Relation Of Double-Lobed Quasars In The FIRST Survey

, 1997
In previous attempts to measure Omega_0 from the angular size-redshift (theta-z) relation of double-lobed radio sources, the observed data have been consistent with a static Euclidean universe, rather than with Friedmann models, and past authors have ...
Becker, Robert H., Buchalter, Ari, Helfand, David J., White, Richard L.   +3 more
core   +1 more source

The Sloan Digital Sky Survey Reverberation Mapping Project: No Evidence for Evolution in the M-sigma Relation to z~1 [PDF]

, 2015
We present host stellar velocity dispersion measurements for a sample of 88 broad-line quasars at 0.10.6) from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project.
Bizyaev, Dmitry, Brandt, W. N., Denney, Kelly D., Greene, Jenny E., Ho, Luis C., Horne, Keith, Jiang, Linhua, Kochanek, Christopher S., McGreer, Ian D., Merloni, Andrea, Pan, Kaike, Peterson, Bradley M., Petitjean, Patrick, Schneider, Donald P., Schulze, Andreas, Shen, Yue, Strauss, Michael A., Tao, Charling, Trump, Jonathan R.   +18 more
core   +4 more sources

SBS 0909+532: A New Double Gravitational Lens or Binary Quasar? [PDF]

The Astrophysical Journal, 1997
The z=1.377, B=17.0 mag quasar SBS 0909+532 A, B is a double with two images separated by 1.107 +/- 0.006 arcsec. Because the faint image has an emission line at the same wavelength as the MgII 2798 A emission line of the quasar, and lacks the broad MgIb absoption feature expected for a star with the same colors (a K star), we conclude that image B is ...
Kochanek, C. S., Falco, E. E., Schild, R., Dobrzycki, A., Engels, D., Hagen, H. -J.   +5 more
openaire   +2 more sources

Satellites and Small Bodies With ALMA: Insights Into Solar System Formation and Evolution

AGU Advances, Volume 6, Issue 6, December 2025.
Abstract Our understanding of the formation and evolution of planetary systems has made major advances in the past decade. This progress has been driven in large part by the Atacama Large Millimeter/submillimeter Array (ALMA), which has given us an unprecedented view of solar system bodies themselves, and of the structure and chemistry of forming ...
Katherine de Kleer, Michael E. Brown, Martin Cordiner, Richard Teague   +3 more
wiley   +1 more source

Spectroscopy of Quasar Candidates from SDSS Commissioning Data [PDF]

, 1998
The Sloan Digital Sky Survey has obtained images in five broad-band colors for several hundred square degrees. We present color-color diagrams for stellar objects, and demonstrate that quasars are easily distinguished from stars by their distinctive ...
Annis, James, Fan, Xiaohui, Gunn, James E., Hennessy, Gregory S., Ivezic, Zeljko, Knapp, Gillian R., Lupton, Robert H., Munn, Jeffrey A., Newberg, Heidi J., Schneider, Donald P., Strauss, Michael A., Yanny, Brian   +11 more
core   +3 more sources

A Comparative Study of VTEC Estimates Derived From S/X VLBI and VGOS Observations

Space Weather, Volume 23, Issue 12, December 2025.
Abstract The ionosphere, which strongly varies in time and space, is one of the largest error sources for microwave measurements, if not accounted for accurately. Especially for single‐frequency observations, precise ionospheric models are needed to correct for the ionospheric delays. This study explores the utility of Very Long Baseline Interferometry
Arno Rüegg, Grzegorz Kłopotek, Benedikt Soja   +2 more
wiley   +1 more source