Results 81 to 90 of about 7,225,990 (222)

Phase-resolved Deadtime of the Crab Pulsar Using IXPE Data

The Astrophysical Journal
After receiving an X-ray photon, an X-ray detector is not operational for a duration known as deadtime. It is detector specific and its effect on the data depends upon the luminosity of the source.
M. Vivekanand
doaj   +1 more source

Mildly Super-Eddington Accretion onto Slowly Spinning Black Holes Explains the X-Ray Weakness of the Little Red Dots

The Astrophysical Journal
JWST has revealed a population of low-luminosity active galactic nuclei at z > 4 in compact, red hosts (the “Little Red Dots,” or LRDs), which are largely undetected in X-rays.
Fabio Pacucci, Ramesh Narayan
doaj   +1 more source

Symptom‐Based Machine Learning Framework for Early Syndrome Coronavirus 2 (SARS‐CoV‐2) Infection Prediction

Applied AI Letters, Volume 8, Issue 1, February 2027.
This graphical abstract illustrates a symptom‐based machine learning framework for early prediction of SARS‐CoV‐2 infection. Clinical inputs such as SpO2, fever, cough, fatigue, and comorbidities are collected and preprocessed, followed by feature selection using a random forest‐based recursive elimination method.
Abdul Manan Koli, Syed Immamul Ansarullah, Ab Rashid Dar, Khair Ul Nisa, Anurag Sinha, Sami Alshmrany, Ravi Shankar Kumar, Mohd Asif Shah, Shreyash Srivastva, Amar Jeet   +9 more
wiley   +1 more source

Landscape of Coronal X-Ray Variability and Cycles

The Astronomical Journal
Coronal (1–10 MK) X-rays display dramatic variability over the Sun’s iconic 11 yr magnetic dynamo cycle: already a factor of 4 in the soft 0.1–2.4 keV “ROSAT band,” soaring to more than 100 at harder energies (>10 keV).
Thomas Ayres
doaj   +1 more source

Best Practices in Open and Reproducible Antarctic Marine Sediment Core Research

Perspectives of Earth and Space Scientists, Volume 7, Issue 1, December 2026.
Abstract Marine sediment cores from Antarctica are archived by national programs for reuse and resampling by future researchers, creating a resourceful way to conduct Antarctic science. With reduced budgets to conduct Antarctic field work and to collect new sediment cores offshore of the icy continent, the accessibility of these archived cores and ...
L. E. Miller, R. A. Venturelli, L. O. Prothro, N. Varela, M. Szemak, J. Ruggiero, A. Vega‐González, A. P. Lepp, V. Stanley, K. Vadman, C. Fritz, K. Tinto, F. Nitsche   +12 more
wiley   +1 more source

The Chandra X-Ray Observatory

, 2001
The Chandra X-Ray Observatory is the X-ray component of NASA's Great observatories which also includes the recently decommissioned Compton Gamma Ray Observatory, the Hubble Space Telescope, and the soon to be launched Space Infra Red Telescope Facility ...
Weisskopf, M. C.
core  

Progress in Multi-wavelength and Multi-Messenger Observations of Blazars and Theoretical Challenges

Galaxies, 2019
This review provides an overview of recent advances in multi-wavelength and multi-messenger observations of blazars, the current status of theoretical models for blazar emission, and prospects for future facilities.
Markus Böttcher
doaj   +1 more source

Detecting the Oceanic Moho Using Teleseismic P‐Wave Coda Autocorrelations of Ocean Bottom Seismograph Records

Geophysical Research Letters, Volume 53, Issue 21, 16 November 2026.
Abstract Although active‐source seismic methods can image the oceanic Mohorovičić discontinuity (Moho) at high resolution, their high cost motivates passive approaches using OBS, for which receiver functions (RF) are often complicated by instrument tilt, azimuthal misalignment, sedimentary layers, and water‐column reverberations.
Guanghui Han, Chen Cai, Shaoping Lu, Shaozhe Dong, Jiandong Huang, Haixia Zhang, Run Jiang   +6 more
wiley   +1 more source

Athena+: The first Deep Universe X-ray Observatory

, 2013
Trabajo presentado al Annual Meeting of the French Society of Astronomy and Astrophysics (SF2A), celebrado en Montpellier del 4 al 7 de junio de 2013.
Barret, D., Nandra, K., Barcons, X., Fabian, A., den Herder, J., Piro, L., Watson, M., Aird, J., Branduardi-Raymont, G., Cappi, M., Carrera, F., Comastri, A., Costantini, E., Croston, J., Decourchelle, A., Done, C., Dovciak, M., Ettori, S., Finoguenov, A., Georgakakis, A., Jonker, P., Kaastra, J., Matt, G., Motch, C., O'Brien, P., Pareschi, G., Pointecouteau, E., Pratt, G., Rauw, G., Reiprich, T., Sanders, J., Sciortino, S., Willingale, R., Wilms, J.   +33 more
openaire   +4 more sources

Unveiling the Nature of Superorbital Modulation of SMC X-1 Using NinjaSat

The Astrophysical Journal
We report a long-term, high-cadence timing and spectral observation of the X-ray pulsar SMC X-1 using NinjaSat—a 6U CubeSat in low-Earth orbit—covering nearly a full superorbital cycle.
Chin-Ping Hu, Naoyuki Ota, Takuya Takahashi, Tomoshi Takeda, Teruaki Enoto, Toru Tamagawa, Biswajit Paul, Sota Watanabe, Wataru Iwakiri, Tatehiro Mihara, Amira Aoyama, Satoko Iwata, Kaede Yamasaki, Takayuki Kita, Soma Tsuchiya, Mayu Ichibakase, (NinjaSat collaboration)   +16 more
doaj   +1 more source