The tree method is a widely implemented algorithm for collisionless $N$-body simulations in astrophysics well suited for GPU(s). Adopting hierarchical time stepping can accelerate $N$-body simulations; however, it is infrequently implemented and its...
This paper has been withdrawn by the author because the conclusions reached in it are incorrect....
The origin of the magnetic field in galaxies is an open question in astrophysics. Several mechanisms have been proposed related, in general, with the generation of small seed fields amplified by a dynamo mechanism. In general, these mechanisms have...
An MIT astrophysics professor and his son unearth a string of numbers from a time capsule that seem to reveal a cataclysm that will wipe out humanity. Watch trailers & learn more.
We present the composite luminosity function of galaxies for 24 Abell clusters studied in our survey of the Northern Hemisphere, using DPOSS data in the framework of the CRoNaRio collaboration. Our determination of the luminosity function has been...
We report new experimental results obtained on three different laser facilities that show directed laser-driven relativistic electron-positron jets with up to 30 times larger yields than previously obtained and a quadratic (~ E^2) dependence of the p...
Stars are spherical balls of hot, ionized gas (plasma) held together by their own gravity. Stars are the most fundamental building blocks of our universe.
In 1896, Edward Charles Pickering (1846-1919), Director of the Harvard College Observatory (HCO), reported in a trio of publications the observation of "peculiar spectra" of the southern star $ζ$ Puppis, which he attributed to an "element not yet fo...
Citizen science has helped astronomers comb through large data sets to identify patterns and objects that are not easily found through automated processes. The Milky Way Project (MWP), a citizen science initiative on the Zooniverse platform, presents...
Bow shocks are ubiquitous astrophysical phenomena resulting from the supersonic passage of an object through a gas. Recently, pre-transit absorption in UV metal transitions of the hot Jupiter exoplanets HD 189733b and WASP12-b have been interpreted a...
Our present knowledge of the properties of the various planetary bow shocks is briefly reviewed. We do not follow the astronomical ordering of the planets. We rather distinguish between magnetised and unmagnetised planets which groups Mercury and E...
We characterize the mass-dependent evolution in a large sample of more than 8,000 galaxies using spectroscopic redshifts drawn from the DEEP2 Galaxy Redshift Survey in the range 0.4 < z < 1.4 and stellar masses calculated from K-band photometry obt...
Using deep infrared observations conducted with the CISCO imager on the Subaru Telescope, we investigate the field-corrected pair fraction and the implied merger rate of galaxies in redshift survey fields with Hubble Space Telescope imaging. In the...
We present an analysis of the growth of stellar mass with cosmic time partitioned according to galaxy morphology. Using a well-defined catalog of 2150 galaxies based, in part, on archival data in the GOODS fields, we assign morphological types in t...
A lunar occultation event of the Wolf-Rayet star WR 112 (type WC9) has been observed simultaneously from two independent telescopes at lambda = 2.2microns, allowing us to investigate this source with an angular resolution of approx 0.003 arc-second...
Geoffrey. Jeff Kuhn, physicist and astronomer Jeff Remmel, American mathematician Jeff S. Shamma, professor of electrical engineering Jeff Sigafoos, New
Omar Khayyam (1048–1131) was a Persian poet and polymath, known for his contributions to mathematics, astronomy, philosophy, and Persian literature. He
Feb 17, 2026 · Tang orange drink mix was advertised as a 'new breakfast drink discovery' when it was introduced in the '50s, and went on to become a part of pop culture history - especially once NASA …
Have you ever wondered: what is Gemini’s compatibility with other zodiac signs? Shout your love from the rooftops with energetic and outgoing Gemini. This Mutable Air sign brings the lively conversation …
Gemini has two sides. Such is the nature of the “twins,” the symbol that represents this sign. This sign has both plenty. of energy and stamina. Additionally, they’re very clever when it comes to language. …
Gemini Similar: Air Sign Symbolized by twins, this zodiac sign is known for its two-sided nature. It is the third sign in the zodiac characterized by talkativeness and playfulness. People born from May 21st to …
1925 was a dynamic year in American history, reflecting the rapid cultural and technological changes of the decade. On January 1, astronomer Edwin Hubble presented his 1924 findings on the existence of …
Images of black holes encode both astrophysical and gravitational properties. Detecting highly-lensed features in images can differentiate between these two effects. We present an accretion disk emission model coupled to the Adaptive Analytical Ray T...
We present the scientific goals, the strategy and the first results of the REX project, an effort aimed at creating a sizable and statistically complete sample of Radio Emitting X-ray sources (REX) using the available data from a VLA survey and the...
We present 71 Emission Line objects selected from the REX survey. Except for 3 of them, for which the presence of an active nucleus is dubious, all these sources are Active Galactic Nuclei (QSOs, Seyfert galaxies, emission line radiogalaxies). In a...
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We report on the spatial distribution of magnetogram oscillatory power and phase angles between velocity and magnetogram signals as observed with the Michelson Doppler Imager. The dataset is 151.25 arcsec times 151.25 arcsec containing sunspot from...
While graphical records of astronomical/meteorological events before telescopic observations are of particular interest, they have frequently undergone multiple copying and may have been modified from the original. Here, we analyze a graphical record...
Auroral records found in historical archives and cosmogenic isotopes found in natural archives have served as sound proxies of coronal mass ejections (CMEs) and solar energetic particles (SEPs), respectively, for dates prior to the onset of telescopi...
The Wisconsin H-Alpha Mapper (WHAM) has completed a one-degree resolution, velocity-resolved northern sky survey of H-alpha emission from our Galaxy. The unprecedented sensitivity of the instrument and accurate spectral subtraction of atmospheric f...
The Wisconsin H-Alpha Mapper (WHAM) has completed a survey in Balmer Alpha of the entire Northern sky above declination -30 deg. This survey provides the first calibrated, velocity-resolved map of the H-Alpha emission from the Galaxy. With one-degr...
The Wisconsin Plasma Astrophysics Laboratory (WiPAL) is a flexible user facility designed to study a range of astrophysically relevant plasma processes as well as novel geometries that mimic astrophysical systems. A multi-cusp magnetic bucket constru...
Yes, Angel Number 1122 is a powerful manifestation number. This number is a message from the universe that your desires are manifesting, and you have the power to attract abundance in your life. …
The National Academy of Science Astronomy and Astrophysics Survey Committee, in its new Decadal survey entitled Astronomy and Astrophysics in the New Millennium, recommends, as a first priority, the establishment of a National Virtual Observatory....
How did neutrino astronomy evolve? Are there any useful lessons for astronomers and physicists embarking on new observational ventures today? We answer the first question; the reader can can decide if there are any useful parallels for other fields...
Gravitational torques between a planet and gas in the protoplanetary disk result in orbital migration of the planet, and are likely to play an important role in the formation and early evolution of planetary systems. For masses comparable to those...
Recently, a soft black-body component was observed in the early X-ray afterglow of GRB 060218, which was interpreted as shock breakout from the thick wind of the progenitor Wolf-Rayet (WR) star of the underlying Type Ic SN 2006aj. In this paper we...
We demonstrate that in a vacuum-energy-dominated expansion phase, surprisingly neither the decay of matter nor matter-antimatter annihilation into relativistic particles can ever cause radiation to once again dominate over matter in the future hist...
The discovery of 2024 YR4 presented the planetary defense community with the most significant impact threat in almost two decades, reaching level 3 on the Torino scale. The community, now mature and well-organized, responded with a global observation...
At present, the field of astronomical machine learning lacks widely-used benchmarking datasets; most research employs custom-made datasets which are often not publicly released, making comparisons between models difficult. In this paper we present CR...