Results 41 to 50 of about 329,488 (298)
The Astrophysical JournalWe present photometric selection of type 1 quasars in the ≈5.3 deg ^2 XMM-Large Scale Structure survey field with machine learning. We constructed our training and blind-test samples using spectroscopically identified Sloan Digital Sky Survey quasars ...
Jian Huang +6 more
doaj +1 more source
Lifting the Veil on Obscured Accretion: Active Galactic Nuclei Number Counts and Survey Strategies for Imaging Hard X-Ray Missions [PDF]
, 2011 Finding and characterizing the population of active galactic nuclei (AGNs) that produces the X-ray background (XRB) is necessary to connect the history of accretion to observations of galaxy evolution at longer wavelengths.
Ballantyne, D. R. +4 more
core +1 more source
Pediatric Blood &Cancer, EarlyView.ABSTRACT Background and Aims Wilms tumour (WT) has excellent event‐free and overall survival (OS). However, small differences exist between countries participating in the same international study. This led us to examine variation in adherence to protocol recommendations as a potential contributing factor.
Suzanne Tugnait +23 more
wiley +1 more source
The NH Distribution of Hard X-Ray Selected Active Galactic Nuclei in the NEP Field
The Astrophysical JournalX-ray surveys are one of the most unbiased methods for detecting Compton-thick (CT; N _H ≥ 10 ^24 cm ^−2 ) active galactic nuclei (AGN), which are thought to comprise up to 60% of AGN within z ≲ 1.0.
Samantha Creech +11 more
doaj +1 more source
Future Perspectives for Gamma-ray Burst Detection from Space
UniverseSince their first discovery in the late 1960s, gamma-ray bursts have attracted an exponentially growing interest from the international community due to their central role in the most highly debated open questions of the modern research of astronomy ...
Enrico Bozzo +37 more
doaj +1 more source
The Future of X-ray Time Domain Surveys
, 2012 Modern X-ray observatories yield unique insight into the astrophysical time domain. Each X-ray photon can be assigned an arrival time, an energy and a sky position, yielding sensitive, energy-dependent light curves and enabling time-resolved spectra down
Haggard, Daryl, Sivakoff, Gregory R.
core +1 more source
Revealing the structure of land plant photosystem II: the journey from negative‐stain EM to cryo‐EM
FEBS Letters, EarlyView.Advances in cryo‐EM have revealed the detailed structure of Photosystem II, a key protein complex driving photosynthesis. This review traces the journey from early low‐resolution images to high‐resolution models, highlighting how these discoveries deepen our understanding of light harvesting and energy conversion in plants.
Roman Kouřil
wiley +1 more source
The Final Season Reimagined: 30 Tidal Disruption Events from the ZTF-I Survey
The Astrophysical Journal, 2022 Tidal disruption events (TDEs) offer a unique way to study dormant black holes. While the number of observed TDEs has grown thanks to the emergence of wide-field surveys in the past few decades, questions regarding the nature of the observed optical, UV,
Erica Hammerstein +32 more
doaj +1 more source
Comparing Chandra and SIRTF Observations for Obscured Starbursts and AGN at High Redshift
, 2003 Tracking the star formation rate to high redshifts requires knowledge of the contribution from both optically visible and obscured sources. The dusty, optically-obscured galaxies can be located by X-ray and infrared surveys.
A. Zezas +8 more
core +1 more source
Luminosity-dependent unification of Active Galactic Nuclei and the X-ray Baldwin effect [PDF]
, 2013 The existence of an anti-correlation between the equivalent width (EW) of the narrow core of the iron Kalpha line and the luminosity of the continuum (i.e.
Awaki, Hisamitsu +5 more
core +2 more sources