Tootfinder

Ten years (!) ago #OTD the first - and shockingly clear - #GravitationalWave signal was seen by the two LIGO detectors ... rumors flew immediately but the official announcement came only in February 2016: https://telescoper.blog/2025/09/14/a-decade-of-gravitational-waves/ and a lot more in https://ligo.org/wp-content/uploads/2025/09/LIGO-magazine-issue27.pdf plus a long article from back then in https://cplberry.com/2016/02/11/gw150914/ and a 1-1/2-hour documentary at https://www.youtube.com/watch?v=dX4vCNi544w

Commissioning and Testing of IceAct Telescopes at the IceCube Neutrino Observatory
Arun Vaidyanathan, Lars Heuermann
https://arxiv.org/abs/2509.09778 https://

Commissioning and Testing of IceAct Telescopes at the IceCube Neutrino Observatory
IceAct is an array of imaging air Cherenkov telescopes located at the ice surface above the IceCube Neutrino Observatory. Each telescope features a silicon photomultiplier based 61 pixel camera and a Fresnel-lens as imaging optic, resulting in a 12-degree field of view. The design is optimized to be operated in harsh environments, particularly at the South Pole. The setup will consist of seven telescopes in a so-called fly's eye configuration, increasing the field of view to 36^\circ, and an ad…

The Neutrino Kaleidoscope: Searches for Non-Standard Neutrino Oscillations at Neutrino Telescopes with a TeV Muon Accelerator Source
Nicholas W. Kamp, Gray Putnam
https://arxiv.org/abs/2508.09249

The Neutrino Kaleidoscope: Searches for Non-Standard Neutrino Oscillations at Neutrino Telescopes with a TeV Muon Accelerator Source
Muon accelerators, a potential technology for enabling $\mathcal{O}$(10 TeV) parton center of mass energy collisions, would also source an intense, collimated beam of neutrinos at TeV energies. The energy and size of this beam would be excellently matched as a source for existing and planned neutrino telescopes: gigaton-sized detectors of astrophysical neutrinos at and above TeV energies. In this paper, we introduce the technical considerations and scientific reach of pairing a muon accelerator…

Precision spectral measurements of Chromium and Titanium from 10 to 250 GeV$/n$ and sub-Iron to Iron ratio with the Calorimetric Electron Telescope on the ISS
O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, P. Betti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, G. A. de Nolfo, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, M. H. Israel, K. Kasahara, J. Kat…

Precision spectral measurements of Chromium and Titanium from 10 to 250 GeV$/n$ and sub-Iron to Iron ratio with the Calorimetric Electron Telescope on the ISS
The Calorimetric Electron Telescope (CALET), in operation on the International Space Station since 2015, collected a large sample of cosmic-ray (CR) iron and sub-iron events over a wide energy interval. In this paper we report an update of our previous measurement of the iron flux and we present - for the first time - a high statistics measurement of the spectra of two sub-iron elements Cr and Ti in the energy interval from 10 to 250 GeV/n. The analyses are based on 8 years of data. Differently…

Radial Pulsations in Polaris: A Secondary Science Application of Cherenkov Telescopes via Intensity Interferometry
Km Nitu Rai, Prasenjit Saha, Subrata Sarangi
https://arxiv.org/abs/2508.09742

Radial Pulsations in Polaris: A Secondary Science Application of Cherenkov Telescopes via Intensity Interferometry
Ground-based Cherenkov telescopes, although typically inoperative during moonlit nights for gamma-ray observations, offer a valuable opportunity for secondary scientific applications through Intensity Interferometry (II). Recent developments and observations suggest that implementing II instrumentation on existing Imaging Atmospheric Cherenkov Telescopes (IACTs) or the Cherenkov Telescope Array (CTA) can significantly advance optical stellar measurements. Motivated by the resurgence of II effor…

The Atacama Cosmology Telescope: High-redshift measurement of structure growth from the cross-correlation of Quaia quasars and CMB lensing from ACT DR6 and $\textit{Planck}$ PR4
Carmen Embil Villagra, Gerrit Farren, Giulio Fabbian, Boris Bolliet, Irene Abril-Cabezas, David Alonso, Anthony Challinor, Jo Dunkley, Joshua Kim, Niall MacCrann, Fiona McCarthy, Kavilan Moodley, Frank J. Qu, Blake Sherwin, Cristobal Sifon, Alexander van Engelen, Edward J. Wollack

The Atacama Cosmology Telescope: High-redshift measurement of structure growth from the cross-correlation of Quaia quasars and CMB lensing from ACT DR6 and $\textit{Planck}$ PR4
We measure the amplitude of matter fluctuations over a wide range of redshifts by combining CMB lensing observations from ACT DR6 and $\textit{Planck}$ PR4 with the overdensity of quasars from Quaia, a $\textit{Gaia}$ and $\textit{unWISE}$ quasar catalog. Our analysis includes the CMB lensing power spectrum from ACT DR6, the auto-correlation of two Quaia quasar samples centered at $z \simeq 1.0$ and $z \simeq 2.1$, and their cross-correlations with CMB lensing from both ACT DR6 and $\textit{Pla…

Advancements in the IceAct Energy Spectrum Analysis
Larissa Paul (for the IceCube Collaboration)
https://arxiv.org/abs/2507.08779 https://

Advancements in the IceAct Energy Spectrum Analysis
The IceAct telescopes are Imaging Air Cherenkov telescopes installed as part of the IceCube Neutrino Observatory at the geographic South Pole. They consist of a 61 pixel camera and are small and robust to withstand the harsh environmental conditions. IceAct detects Cherenkov light produced by cosmic-ray particles with energies above approximately 10\,TeV interacting inside the atmosphere, which is complementary to the measurement of the air shower at the surface by IceTop and the high-energy mu…

In-orbit Spectral Calibration Prospects for the COSI Space Telescope
Aravind B. Valluvan, Steven E. Boggs, Savitri Gallego, Jarred Roberts, Gabriel Brewster, Sophia Haight, Carolyn Kierans, Sean Pike, Albert Y. Shih, John A. Tomsick, Andreas Zogaluer
https://arxiv.org/abs/2508.10172

In-orbit Spectral Calibration Prospects for the COSI Space Telescope
The Compton Spectrometer and Imager is an upcoming NASA space telescope in the MeV range. COSI's primary science goals include precisely mapping nuclear line and positron annihilation emission in the Milky Way galaxy through Compton imaging. This relies on our ability to maintain COSI's spectral performance over its mission lifetime. Changes to the detectors' gain characteristics over time will result in a non-linear stretching of the entire energy range. Moreover, observations from past MeV te…

On-axis afocal telescopes as framework for Cubesat based astronomical imagers and slit-less spectrographs
Anwesh Kumar Mishra, Gourav Banerjee, Rekhesh Mohan, Maheswar Gopinathan
https://arxiv.org/abs/2507.08323

On-axis afocal telescopes as framework for Cubesat based astronomical imagers and slit-less spectrographs
Cubesats present unique opportunities for observational astronomy in the modern era. They are useful in observing difficult-to-access wavelength regions and long-term monitoring of interesting astronomical sources. However, conventional telescope designs are not necessarily the best fit for restricted envelope of a Cubesat. Additionally, fine-pointing stability on these platforms is difficult due to the low mass of the spacecraft and special allocations within the optical design are needed to a…

SKYSURF VIII -- Modeling SKYSURF Completeness Data for Comparison to the Hubble Space Telescope Exposure Time Calculator
Zachary Goisman (Arizona State University School of Earth and Space Exploration, Arizona State University School of Electrical and Computer Engineering), Timothy Carleton (Arizona State University School of Earth and Space Exploration), Seth H. Cohen (Arizona State University School of Earth and Space Exploration), Delondrae Carter (Arizona State University School of…

SKYSURF VIII -- Modeling SKYSURF Completeness Data for Comparison to the Hubble Space Telescope Exposure Time Calculator
Accurately assessing image source completeness is critical for interpreting measurements on telescope data. Using the Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS) data from the Hubble Space Telescope ($HST$) archival project "SKYSURF", we model galaxy completeness as a function of the exposure time and background of an image. This is accomplished by adding simulated objects with varying magnitudes and sizes into these images, and determining the detection rate for each set o…