Here’s Hubble’s First Image in its New Pointing Mode This is probably what the demise of the Hubble Space Telescope was always going to look like: components failing one by one, with no way to replace them. In the last few months, the Hubble has repeatedly gone into safe mode as one of its remaining three gyros keeps giving faulty readings. But the Hubble and the people operating it are resilient and resourceful. The telescope is back to science operations now, though in single gyro mode. NASA has released the first image the Hubble captured in this mode, and it’s clear that the Hubble isRead More →

Slingshotting Around the Sun Would Make a Spacecraft the Faster Ever NASA is very interested in developing a propulsion method to allow spacecraft to go faster. We’ve reported several times on different ideas to support that goal, and most of the more successful have utilized the Sun’s gravity well, typically by slingshotting around it, as is commonly done with Jupiter currently. But, there are still significant hurdles when doing so, not the least of which is the energy radiating from the Sun simply vaporizing anything that gets close enough to utilize a gravity assist. That’s the problem a project supported by NASA’s Institute for AdvancedRead More →

Perseverance Found Some Strange Rocks. What Will They Tell Us? NASA’s Perseverance Rover has left Mount Washburn behind and arrived at its next destination, Bright Angel. It found an unusual type of rock there that scientists are calling ‘popcorn rock.’ The odd rock is more evidence that water was once present in Jezero Crater. Perseverance’s mission is centred on life on ancient Mars. Along with searching for fossilized evidence of ancient life, it’s searching for and trying to understand environments that could’ve supported life. That’s why it’s in Jezero Crater, an ancient paleolake with a delta of sediments and other intriguing geological features. On SolRead More →

Marsquakes Can Help Us Find Water on the Red Planet Earth is a seismically active planet, and scientists have figured out how to use seismic waves from Earthquakes to probe its interior. We even use artificially created seismic waves to identify underground petroleum-bearing formations. When the InSIGHT (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) lander was sent to Mars, it sensed Marsquakes to learn more bout the planet’s interior. Researchers think they can use Marsquakes to answer one of Mars’ most pressing questions: Does the planet hold water trapped in its subsurface? Ground-penetrating radar can tell us what’s underground on Earth. However, itRead More →

If We Want To Find Life-Supporting Worlds, We Should Focus on Small Planets With Large Moons There’s no perfect way of doing anything, including searching for exoplanets. Every planet-hunting method has some type of bias. We’ve found most exoplanets using the transit method, which is biased toward larger planets. Larger planets closer to their stars block more light, meaning we detect large planets transiting in front of their stars more readily than we detect small ones. That’s a problem because some research says that life-supporting planets are more likely to be small, like Earth. It’s all because of moons and streaming instability. Consider Earth’s Moon.Read More →

Earth’s atmosphere is our best defense against nearby supernovae, study suggests Earth’s protective atmosphere has sheltered life for billions of years, creating a haven where evolution produced complex lifeforms like us. The ozone layer plays a critical role in shielding the biosphere from deadly UV radiation. It blocks 99% of the sun’s powerful UV output. Earth’s magnetosphere also shelters us. Go to SourceRead More →

The Earliest Merging Quasars Ever Seen Studying the history of science shows how often serendipity plays a role in some of the most important discoveries. Sometimes, the stories are apocryphal, like Newton getting hit on the head with an apple. But sometimes, there’s an element of truth to them. That was the case for a new discovery of the oldest pair of merging quasars ever discovered – and it all started with a pair of red blots on a picture. Those red blots were on a very particular picture – one taken by the Hyper Subprime-Cam on the Subaru telescope in Manuakea, Hawai’i. Yoshiki MatsuokaRead More →

Observations explore stellar content of nearby young open cluster Berkeley 59 Astronomers from India and Thailand have observed a young nearby open cluster known as Berkeley 59. Results of the observational campaign, published June 12 on the pre-print server arXiv, deliver essential information regarding low-mass stellar and substellar content of this cluster. Go to SourceRead More →

A Trifecta of Modelling Tools: Navigating COMPAS, Shark and Bayesian Inference for Binary Black Hole Model Selection Liana Rauf, Cullan Howlett, Simon Stevenson, Jeff Riley arXiv:2406.11885v1 Announce Type: new Abstract: Gravitational waves (GWs) have revealed surprising properties of binary black hole (BBH) populations, but there is still mystery surrounding how these compact objects evolve. We apply Bayesian inference and an efficient method to calculate the BBH merger rates in the Shark host galaxies, to determine the combination of COMPAS parameters that outputs a population most like the GW sources from the LVK transient catalogue. For our COMPAS models, we calculate the likelihood with and withoutRead More →

Magnetic Suppression of Cosmic Rays’ Flux in $boldsymbol{f(R)}$ and $boldsymbol{f(Q)}$ Theories of Gravity Swaraj Pratim Sarmah, Umananda Dev Goswami arXiv:2406.11902v1 Announce Type: new Abstract: We investigate the effects of magnetic diffusion on the spectrum of ultra-high energy cosmic rays (UHECRs) from a cosmological perspective. To this end, we consider two modified theories of gravity (MTGs), namely, the $f(R)$ gravity and a symmetric teleparallel gravity, also known as $f(Q)$ gravity. Utilizing these two MTGs, we calculate the suppression in the flux of UHECRs for a collection of sources. Non-evolution (NE) and cosmic star formation rate (SFR) scenarios have been considered in our calculation of the suppressionRead More →

The stellar halo of the Milky Way traced by blue horizontal-branch stars in the Subaru Hyper Suprime-Cam Survey Tetsuya Fukushima, Masashi Chiba, Mikito Tanaka, Kohei Hayashi, Daisuke Homma, Sakurako Okamoto, Yutaka Komiyama, Masayuki Tanaka, Nobuo Arimoto, Tadafumi Matsuno arXiv:2406.11923v1 Announce Type: new Abstract: We select blue-horizontal branch stars (BHBs) from the internal data release of the Hyper Suprime-Cam Subaru Strategic Program to reveal the global structure of the Milky Way (MW) stellar halo. The data are distributed over $sim 1,100$~deg$^2$ area in the range of $18.5r_{rm b}$; the statistical difference between these fitting profiles is small. Both profiles are found to show prolate shapes havingRead More →

Refining Galactic primordial black hole evaporation constraints Pedro De la Torre Luque, Jordan Koechler, Shyam Balaji arXiv:2406.11949v1 Announce Type: new Abstract: We revisit the role of primordial black holes (PBHs) as potential dark matter (DM) candidates, particularly focusing on light asteroid-mass PBHs. These PBHs are expected to emit particles through Hawking evaporation that can generate cosmic rays (CRs), eventually producing other secondary radiations through their propagation in the Milky Way, in addition to prompt emissions. Here, we perform a comprehensive analysis of CR signals resulting from PBH evaporation, incorporating the full CR transport to account for reacceleration and diffusion effects within the Milky Way. InRead More →

Reducing Model Error Using Optimised Galaxy Selection: Weak Lensing Cluster Mass Estimation Markus Michael Rau, Florian K’eruzor’e, Nesar Ramachandra, Lindsey Bleem arXiv:2406.11950v1 Announce Type: new Abstract: Galaxy clusters are one of the most powerful probes to study extensions of General Relativity and the Standard Cosmological Model. Upcoming surveys like the Vera Rubin Observatory’s Legacy Survey of Space and Time are expected to revolutionise the field, by enabling the analysis of cluster samples of unprecedented size and quality. To reach this era of high-precision cluster cosmology, the mitigation of sources of systematic error is crucial. A particularly important challenge is bias in cluster mass measurements inducedRead More →

Spatial and Spectral Characterization of the Gravitational-wave Background with the PTA Optimal Statistic Kyle A. Gersbach, Stephen R. Taylor, Patrick M. Meyers, Joseph D. Romano arXiv:2406.11954v1 Announce Type: new Abstract: Pulsar timing arrays (PTAs) have made tremendous progress and are now showing strong evidence for the gravitational-wave background (GWB). Further probing the origin and characteristics of the GWB will require more generalized analysis techniques. Bayesian methods are most often used but can be computationally expensive. On the other hand, frequentist methods, like the PTA Optimal Statistic (OS), are more computationally efficient and can produce results that are complementary to Bayesian methods, allowing for stronger statisticalRead More →

Constraining modified gravity with weak lensing peaks Christopher T. Davies, Joachim Harnois-D’eraps, Baojiu Li, Benjamin Giblin, C’esar Hern’andez-Aguayo, Enrique Paillas arXiv:2406.11958v1 Announce Type: new Abstract: It is well established that maximizing the information extracted from upcoming and ongoing stage-IV weak-lensing surveys requires higher-order summary statistics that complement the standard two-point statistics. In this work, we focus on weak-lensing peak statistics to test two popular modified gravity models, $f(R)$ and nDGP, using the FORGE and BRIDGE weak-lensing simulations, respectively. From these simulations we measure the peak statistics as a function of both cosmological and modified gravity parameters simultaneously. Our findings indicate that the peak abundance isRead More →

Exploring the fate of primordial discs in Milky Way-sized galaxies with the GigaEris simulation Floor van Donkelaar, Lucio Mayer, Pedro R. Capelo, Piero Madau arXiv:2406.11960v1 Announce Type: new Abstract: Recent observations with JWST and ALMA have unveiled galaxies with regular discs at significantly higher redshifts than previously expected. This appears to be in contrast with constraints on the stellar populations of the Milky Way, suggesting that the bulk of the Galactic thin disc formed after $z=1$, and raises questions about the history, evolution, and survivability of primordial discs. Here, we use GigaEris, a state-of-the-art $N$-body, hydrodynamical, cosmological “zoom-in” simulation with a billion particles within theRead More →

The properties of AGN in dwarf galaxies identified via SED fitting B. Bichang’a, S. Kaviraj, I. Lazar, R. A. Jackson, S. Das, D. J. B. Smith, A. E. Watkins, G. Martin arXiv:2406.11962v1 Announce Type: new Abstract: Given their dominance of the galaxy number density, dwarf galaxies are central to our understanding of galaxy formation. While the incidence of AGN and their impact on galaxy evolution has been extensively studied in massive galaxies, much less is known about the role of AGN in the evolution of dwarfs. We search for radiatively-efficient AGN in the nearby (0.1 arXiv:2406.11962v1 Announce Type: new Abstract: Given their dominance of theRead More →

Be careful in multi-messenger inference of the Hubble constant: A path forward for robust inference Michael M"uller, Suvodip Mukherjee, Geoffrey Ryan arXiv:2406.11965v1 Announce Type: new Abstract: Multi-messenger observations of coalescing binary neutron stars (BNSs) are a direct probe of the expansion history of the universe and carry the potential to shed light on the disparity between low- and high-redshift measurements of the Hubble constant $H_0$. To measure the value of $H_0$ with such observations requires pristine inference of the luminosity distance and the true source redshift with minimal impact from systematics. In this analysis, we carry out joint inference on mock gravitational wave (GW) signalsRead More →