Results 61 to 70 of about 91,098 (240)

Mid‐infrared detection and characterization of refractory inclusions in CM and CO chondrites: A non‐destructive approach for returned space samples

Meteoritics &Planetary Science, Volume 60, Issue 3, Page 544-569, March 2025.
Abstract Refractory inclusions (RIs) in chondrites are widely used as tracers of early solar system formation conditions. In the context of sample‐return missions, a non‐destructive and non‐invasive analytical tool that can rapidly detect and characterize RIs in space samples during their early phase of study is highly needed.
Jean Charlier, Alice Aléon‐Toppani, Rosario Brunetto, Jérôme Aléon, Ferenc Borondics   +4 more
wiley   +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 the contribution of faint quasars to the hard X-ray component of the cosmic X-ray background.
arxiv   +1 more source

A Possible Bias Model for Quasars [PDF]

Astrophys.J. 502 (1998) L95, 1998
We propose that the majority of quasars at redshift $z\sim 1 - 5$ formed in the environment of new born collapsed halos with 1-D velocity dispersion $\sigma_v^{1d} \sim 400 \kms$. The harboring coefficient $f$ of quasars per halo and the lifetime of quasars depend only on local process, not modulated by the density inhomogeneities on scales larger than
arxiv   +1 more source

DESI z ≳ 5 Quasar Survey. I. A First Sample of 400 New Quasars at z ∼ 4.7–6.6

The Astrophysical Journal Supplement Series, 2023
We report the first results of a high-redshift ( z ≳ 5) quasar survey using the Dark Energy Spectroscopic Instrument (DESI). As a DESI secondary target program, this survey is designed to carry out a systematic search and investigation of quasars at 4.8 <
Jinyi Yang, Xiaohui Fan, Ansh Gupta, Adam D. Myers, Nathalie Palanque-Delabrouille, Feige Wang, Christophe Yèche, Jessica Nicole Aguilar, Steven Ahlen, David M. Alexander, David Brooks, Kyle Dawson, Axel de la Macorra, Arjun Dey, Govinda Dhungana, Kevin Fanning, Andreu Font-Ribera, Satya Gontcho, Julien Guy, Klaus Honscheid, Stephanie Juneau, Theodore Kisner, Anthony Kremin, Laurent Le Guillou, Michael Levi, Christophe Magneville, Paul Martini, Aaron Meisner, Ramon Miquel, John Moustakas, Jundan Nie, Will Percival, Claire Poppett, Francisco Prada, Edward Schlafly, Gregory Tarlé, Mariana Vargas Magana, Benjamin Alan Weaver, Risa Wechsler, Rongpu Zhou, Zhimin Zhou, Hu Zou   +41 more
doaj   +1 more source

Within‐Host Mathematical Modeling of Antibiotic‐phage Treatments on Lysogenic and Nonlysogenic Bacteria Dynamics

Mathematical Methods in the Applied Sciences, Volume 48, Issue 10, Page 10550-10570, 15 July 2025.
ABSTRACT Bacteriophages, or phages (viruses of bacteria), play significant roles in shaping the diversity of bacterial communities within the human gut. A phage‐infected bacterial cell can either immediately undergo lysis (virulent/lytic infection) or enter a stable state within the host as a prophage (lysogeny) until a trigger event, called prophage ...
Hyacinthe M. Ndongmo Teytsa, Ousmane Seydi, Berge Tsanou, Ramsès Djidjou‐Demasse   +3 more
wiley   +1 more source

Properties of Radio-Selected Broad Absorption-Line Quasars from the FIRST Survey [PDF]

Astrophys.J.538:72-82,2000, 2000
In a spectroscopic follow-up to the VLA FIRST survey, the FIRST Bright Quasar Survey (FBQS) has found 29 radio-selected broad absorption line (BAL) quasars. This sample provides the first opportunity to study the properties of radio-selected BAL quasars.
arxiv   +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

Estimators of Bolometric Luminosity and Black Hole Mass with Mid-infrared Continuum Luminosities for Dust-obscured Quasars: Prevalence of Dust-obscured SDSS Quasars

The Astrophysical Journal, 2023
We present bolometric luminosity ( L _bol ) and black hole (BH) mass ( M _BH ) estimators based on mid-infrared (MIR) continuum luminosity (hereafter, L _MIR ) that are measured from infrared (IR) photometric data.
Dohyeong Kim, Myungshin Im, Minjin Kim, Yongjung Kim, Suhyun Shin, Hyunjin Shim, Hyunmi Song   +6 more
doaj   +1 more source

Evaluation of the system accuracy of frameless stereotactic radiosurgery using a combination of cone beam CT, six degrees of freedom couch, and surface image‐guided systems

Journal of Applied Clinical Medical Physics, Volume 26, Issue 6, June 2025.
Abstract Purpose This study aims to evaluate the accuracy of the frameless linear accelerator‐based stereotactic radiosurgery (FSRS) system incorporating cone‐beam CT (CBCT), six degrees of freedom (6‐DoF) couch, room laser, and surface image‐guided (SG) systems.
Hao‐Wen Cheng, Jonathan Li, Sheng‐Hsuan Sun, Guanghua Yan, Chihray Liu   +4 more
wiley   +1 more source

What makes red quasars red? Observational evidence for dust extinction from line ratio analysis

, 2017
Red quasars are very red in the optical through near-infrared (NIR) wavelengths, which is possibly due to dust extinction in their host galaxies as expected in a scenario in which red quasars are an intermediate population between merger-driven star ...
Im, Myungshin, Kim, Dohyeong
core   +1 more source