Results 91 to 100 of about 111,891 (295)

Automated quasar detection [PDF]

Monthly Notices of the Royal Astronomical Society, 1983
The existing spectral searches for quasars have increased the number of quasars known very substantially but have not contributed proportionately to an understanding of the collective properties because of the selection effects. To fully exploit the spectral searches we have developed the technique of automated quasar detection (AQD) using objective ...
Roger G. Clowes, John A. Cooke, Steven M. Beard   +2 more
openaire   +2 more sources

Impact of tumor motion on target delineation and dose calculation accuracy using rapid‐acquisition HyperSight CBCT in online adaptive radiotherapy

Journal of Applied Clinical Medical Physics, Volume 27, Issue 1, January 2026.
Abstract Background HyperSight CBCT offers rapid image acquisition and enhanced image quality, supporting its integration into online adaptive radiotherapy (OART). However, its performance under respiratory‐induced tumor motion requires further evaluation.
Yi‐Fang Wang, Fan Liu, Michael J. Price, Adam C. Riegel   +3 more
wiley   +1 more source

Comprehensive Connection among the Quasars with Different Types of Outflow Absorption Lines

The Astrophysical Journal
It is commonly accepted that outflows from the central regions of quasars play a substantial role in regulating the global properties of the host galaxy. These outflows are typically detected through blueshifted absorption lines.
Xing-Long Peng, Zhi-Fu Chen, Zhi-Cheng He, Ting-Ting Pang, Zhi-Wen Wang   +4 more
doaj   +1 more source

The Race Between Stars and Quasars in Reionizing Cosmic Hydrogen

, 2009
The cosmological background of ionizing radiation has been dominated by quasars once the Universe aged by ~2 billion years. At earlier times (redshifts z>3), the observed abundance of bright quasars declined sharply, implying that cosmic hydrogen was ...
A. Loeb, A. Loeb, A. Soltan, A.S. Eddington, Abraham Loeb, C.-L. Jiao, C.A. Faucher-Giguère, C.W. Morgan, F. Shankar, F. Shankar, I.D. Novikov, J. Magorrian ., J. Silk, J.A. Kollmeier ., J.L. Tinker ., J.S.B. Wyithe, J.S.B. Wyithe, J.S.B. Wyithe, J.S.B. Wyithe, K. Gebhardt ., L. Ferrarese, M. Dijkstra, M. Dijkstra, M.S. Warren, N. Haring, N.I. Shakura, P.F. Hopkins, R. Shafee, R. Shafee ., R.C. Kennicutt, R.C. Telfer, R.L. White, R.M. O'Leary, R.M. O'Leary, S. Poindexter, S. Tremaine ., S. Tremaine ., S. Wyithe, T. Tanaka, T.R. Lauer ., V. Bromm, WMAP collaboration, Y. Li ., Z. Haiman, Z. Haiman   +44 more
core   +1 more source

High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data III: A Color Selected Sample at i^*<20 in the Fall Equatorial Stripe [PDF]

, 2000
This is the third paper in a series aimed at finding high-redshift quasars from five-color (u'g'r'i'z') imaging data taken along the Celestial Equator by the SDSS during its commissioning phase.
Anderson, J E, Annis, J, Bahcall, N A, Becker, R H, Brunner, R J, Csabai, I N, Davis, M, Doi, M M, Fan, X H, Fukugita, M, Gunn, J E, Hennessy, G S, Hindsley, R B, Ivezic, Z, Knapp, G R, Lupton, R H, Mckay, T A, Munn, J A, Newman, J A, Pier, J R, Richards, G T, Schneider, D P, Strauss, M A, Szalay, A S, White, R L, York, D G   +25 more
core   +2 more sources

Commissioning and robustness evaluation of external laser sensor for respiratory gating in carbon‐ion radiotherapy

Journal of Applied Clinical Medical Physics, Volume 27, Issue 1, January 2026.
Abstract Background Respiratory‐induced tumor motion remains a significant challenge in carbon‐ion radiotherapy (CIRT), potentially compromising dose accuracy and escalating dose in nearby organs. Although belt‐based sensors are commonly used for gating, issues related to setup reproducibility and patient comfort increased the demand for laser‐based ...
Tae‐Ho Kim, Soorim Han, Dohyeon Yoo, Sangmin Lee, Taegeon Oh, Dongjoon Lee, Changhwan Kim, Min Cheol Han, Chae‐Seon Hong, Jin Sung Kim   +9 more
wiley   +1 more source

Narrow [O iii] Emission Lines as a Potential Proxy for the Evolutionary Stage of Quasars

The Astrophysical Journal
Radio spectral shape of quasars can provide insight into the ages of quasars. We have compiled data for 1804 quasars with z ≲ 1 from the Sloan Digital Sky Survey (SDSS).
Zhi-fu Chen, Zhe-Geng Chen, Xing-long Peng, Wei-rong Huang   +3 more
doaj   +1 more source

Luminous Quasars Do Not Live in the Most Overdense Regions of Galaxies at z~4

, 2017
We present the cross-correlation between 151 luminous quasars ($M_{ \mathrm{UV}} < -26$) and 179 protocluster candidates at $z \sim 3.8$, extracted from the Wide imaging survey ($ \sim 121~ $deg$^2$) performed with a part of the Hyper Suprime-Cam Subaru ...
Akiyama, Masayuki, Chiang, Yi-Kuan, Coupon, Jean, Harikane, Yuichi, Ichikawa, Kohei, Imanishi, Masatoshi, Ishikawa, Shogo, Kashikawa, Nobunari, Kodama, Tadayuki, Komiyama, Yutaka, Lee, Chien-Hsiu, Lin, Yen-Ting, Marinello, Murilo, Miyazaki, Satoshi, Nagao, Tohru, Niino, Yuu, Nishizawa, Atushi J., Ono, Yoshiaki, Onoue, Masafusa, Ouchi, Masami, Overzier, Roderik, Tanaka, Masayuki, Toshikawa, Jun, Uchiyama, Hisakazu, Wang, Shiang-Yu   +24 more
core   +1 more source

X-ray Observations of Gravitationally Lensed Quasars; Evidence for a Hidden Quasar Population [PDF]

, 1999
The large magnification factors of gravitationally lensed (GL) systems allow us to investigate the properties of quasars with X-ray luminosities that are substantially lower than those of unlensed ones and also provide an independent means of estimating ...
Bade N., Brinkmann W., Courbin F., G. Chartas, Kormann R., Patnaik A. R., Reeves J. N., Reimers D., Schartel N., Smette A., Tinney C. G., Yuan W.   +11 more
core   +2 more sources

Dust emission from quasars and quasar host galaxies [PDF]

Monthly Notices of the Royal Astronomical Society, 1999
We test emission models of circum-nuclear dust torii around quasars, at low and high redshifts, by using a large collection of photometric data for an unbiased sample of 120 optically-selected objects with millimetric and sub-millimetric fluxes, including new unpublished data.
Andreani, Paola, Franceschini, Alberto, Granato, Gianluigi   +2 more
openaire   +2 more sources