The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All of the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 deg2 of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include the measured abundances of 15 different elements for each star. In total, SDSS-III added 5200 deg2 of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 deg2; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra.
Abrikosov, Gorkov, Dzyaloshinski, Methods of quantum field theory in statistical physics Fetter, Walecka, Quantum theory of many-particle systems T. Schaefer, Quark Matter, hep-ph/0304281. J. Kogut, M. Stephanov, The Phases of QCD, Cambridge University Press (2004). K. Rajagopal, F. Wilczek, The Condensed Matter Physics of QCD, hep-ph/0011333. J. Lattimer and M. Prakash, The Physics of Neutron Stars, astro-ph/0405262. D. Kaplan, Five lectures on effective field theory, nucl-th/0510023.
We all love the ecstasy that comes with submitting papers to journals or arXiv. Some have described it as yeeting their back-breaking products of labor into the void, wishing they could never deal with them ever again. The very act of yeeting papers onto arXiv contributes to the expansion of the arXiverse; however, we have yet to quantify our contribution to the cause. In this work, I investigate the expansion of the arXiverse using the arXiv astro-ph submission data from 1992 to date. I coin the term "the arXiverse constant", $a_0$, to quantify the rate of expansion of the arXiverse. I find that astro-ph as a whole has a positive $a_0$, but this does not always hold true for the six subcategories of astro-ph. I then investigate the temporal changes in $a_0$ for the astro-ph subcategories and astro-ph as a whole, from which I infer the fate of the arXiverse.
Baikal-GVD Collaboration, :, V. A. Allakhverdyan
et al.
We present an updated measurement of the diffuse astrophysical neutrino flux using Baikal-GVD cascade data collected between April 2018 to March 2024. In this period, the detector grew from 15% to 55% of its baseline cubic kilometer configuration. The diffuse astrophysical neutrino flux is detected with a statistical significance of 5.1 $σ$. Assuming a single power law model of the astrophysical neutrino flux with identical contribution from each neutrino flavor, the following best-fit parameter values are found: the spectral index $γ_{astro}$ = 2.64$^{+0.09}_{-0.11}$ and the flux normalization $φ_{astro}$ = 4.42$^{+2.31}_{-1.29}\times10^{-18} \text{GeV}^{-1}\text{cm}^{-2}\text{s}^{-1}\text{sr}^{-1}$ per one flavor at 100 TeV. These results are broadly consistent with IceCube measurements.
The KM3NeT collaboration has reported the detection of the highest energy neutrino event observed to date. The energy of the event is of the order of 220 PeV hinting towards a neutrino flux at the highest energies. In this article, the potential blazar origin for this event is explored. The publicly available Astro-Multimessenger Modeling software is used to model the blazar gamma-ray and neutrino fluxes. It is concluded that a population of blazars could produce the diffuse flux compatible with the observation of the ultra-high energy event detected by the KM3NeT/ARCA detector. At the same time, the gamma-ray flux produced by such a population of blazars is consistent with the diffuse gamma-ray flux measured by the Fermi Large Area Telescope.
We set up and perform collision rate simulations between dark matter in the form of asteroid-mass primordial black holes (PBHs) and white dwarf stars. These encounters trigger prompt detonations and could be the key to solving the ignition mystery of type Ia supernovae. Our framework is flexible enough to cover the full range of progenitor white dwarf masses, host galaxy stellar masses, galactocentric radial offsets, and cosmic time. The rate distribution pattern is consistent with exhaustive literature observational determinations for a slightly extended log-normal PBH mass spectrum. Most strikingly, the so far unexplained brightness distribution comes out without finetuning. We find no severe contradictions, except that the inferred PBH mass scale is unpredicted from first principles.
CompOSE (CompStar Online Supernovae Equations of State) is an online repository of equations of state (EoS) for use in nuclear physics and astrophysics, e.g., in the description of compact stars or the simulation of core-collapse supernovae and neutron-star mergers, see https://compose.obspm.fr. The main services, offered via the website, are: a collection of data tables in a flexible and easily extendable data format for different EoS types and related physical quantities with extensive documentation and referencing; software for download to extract and to interpolate these data and to calculate additional quantities; webtools to generate EoS tables that are customized to the needs of the users and to illustrate dependencies of various EoS quantities in graphical form. This manual is an update of previous versions that are available on the CompOSE website, at arXiv:1307.5715 [astro-ph.SR], and that was originally published in the journal “Physics of Particles and Nuclei” with doi:10.1134/S1063779615040061. It contains a detailed description of the service, containing a general introduction as well as instructions for potential contributors and for users. Short versions of the manual for EoS users and providers will also be available as separate publications.
A measurement of the diffuse astrophysical neutrino spectrum is presented using IceCube data collected from 2011-2022 (10.3 years). We developed novel detection techniques to search for events with a contained vertex and exiting track induced by muon neutrinos undergoing a charged-current interaction. Searching for these starting track events allows us to not only more effectively reject atmospheric muons but also atmospheric neutrino backgrounds in the southern sky, opening a new window to the sub-100 TeV astrophysical neutrino sky. The event selection is constructed using a dynamic starting track veto and machine learning algorithms. We use this data to measure the astrophysical diffuse flux as a single power law flux (SPL) with a best-fit spectral index of $γ= 2.58 ^{+0.10}_{-0.09}$ and per-flavor normalization of $φ^{\mathrm{Astro}}_{\mathrm{per-flavor}} = 1.68 ^{+0.19}_{-0.22} \times 10^{-18} \times \mathrm{GeV}^{-1} \mathrm{cm}^{-2} \mathrm{s}^{-1} \mathrm{sr}^{-1}$ (at 100 TeV). The sensitive energy range for this dataset is 3 - 550 TeV under the SPL assumption. This data was also used to measure the flux under a broken power law, however we did not find any evidence of a low energy cutoff.
It was recently claimed (arXiv:2409.09081v1 [astro-ph.HE]) that accretion of ordinary matter on black holes of mass $(6\times 10^{14}-4\times10^{19})\,$g would be inhibited by quantum mechanical effects, namely the de Broglie wavelength of the electron being larger than the Schwarzschild radius. However the conclusion is based on considering accretion of a single atom over the age of the Universe. There is no suppression of the accretion rate per atom on such black holes.
A. V. Glushkov, L. T. Ksenofontov, K. G. Lebedev
et al.
We provide a detailed commentary on the energy calibration of the TA experiment described in our paper (arXiv:2404.16948 [astro-ph.HE]). That paper concludes that the TA energy estimation, which is tied to optical measurements, might be incorrect. A response from members of the TA Collaboration (arXiv:2407.12892 [astro-ph.HE]) states that this conclusion is wrong and"stems from a misinterpretation and an incorrect application of the TA energy deposit formula". Here we demonstrate that our formula for energy deposit is not in fact a rescaled modification of the TA equation, but follows from description of the processes occurring during the passage of charged particles through 1.2 cm thick scintillator. Our estimation of the TA detector response implies the correctness of the cosmic ray spectrum derived from readings of surface detectors of the array.
The standard model of particle physics describes matter and antimatter as coming from the same fields and this fact has been confirmed experimentally. It is then curious that the observable universe is made of matter and not antimatter. We will first discuss the evidence that we live in a matter-dominated (or matter-antimatter asymmetric) Universe and then proceed to discuss if this can be explained according to our current understanding of the cosmology and particle physics. We will argue that an important process known as baryogenesis to generate a cosmic matter-antimatter asymmetry had to occur before the Universe was a few second old. Then, we will discuss the necessary ingredients for a successful baryogenesis and point out that the current model contains all the ingredients but not in a sufficient amount. Finally, we will discuss possible extensions to the current model which allow successful baryogenesis and how they can be tested experimentally. Interestingly, they might also be connected to other open puzzles in the fundamental physics, like the tiny neutrino mass.
Se presenta una introducción a los fundamentos de la Relatividad General y la noción de Agujeros Negros de una manera elemental, asumiendo conocimientos básicos de Física, y relegando a notas al pie de página aquellas acotaciones técnicas que requieran mayores conocimientos. Se da además una breve introdución histórica del concepto de agujero negro, y se mencionan los notables avances recientes en el campo experimental: la detección en 2015 de ondas gravitacionales en LIGO y las imágenes obtenidas por el Event Horizon Telescope.
The measurement of a diffuse astrophysical neutrino flux using starting track events marks the first time IceCube has observed and subsequently measured the astrophysical diffuse flux using a dataset composed primarily of starting track events. Starting tracks combine an excellent angular and energy resolution. This enables us to take advantage of the self-veto effect in the southern sky reducing the atmospheric neutrino rate allowing us to detect astrophysical neutrinos to energies well below 100 TeV. We measure the astrophysical flux as $φ^{per-flavor}_{Astro}=1.68^{+0.19}_{-0.22}$(at 100 TeV) and $γ_{Astro} = 2.58^{+0.10}_{-0.09}$ assuming a single power law flux. The astrophysical flux 90% sensitive energy range is 3 TeV to 500 TeV, extending IceCube's reach to the low energy astrophysical flux by an order of magnitude. A brief summary of tests performed to search for neutrinos from the galactic plane using this dataset is also provided. With this sample, we did not find statistically significant evidence for emission from the galactic plane. We then tested the impact of these galactic plane neutrinos on the isotropic diffuse flux, with at most 10% effect on the overall normalization and negligible impact to the spectral index.
A. Berthereau, L. Guillemot, P. C. C. Freire
et al.
PSR J1528-3146 is a 60.8 ms pulsar orbiting a heavy white dwarf (WD) companion, with an orbital period of 3.18 d. This work aimed at characterizing the pulsar's astrometric, spin and orbital parameters by analyzing timing measurements conducted at the Parkes, MeerKAT and Nançay radio telescopes over almost two decades. The measurement of post-Keplerian perturbations to the pulsar's orbit can be used to constrain the masses of the two component stars of the binary, and in turn inform us on the history of the system. We analyzed timing data from the Parkes, MeerKAT and Nançay radio telescopes collected over $\sim$16 yrs, obtaining a precise rotation ephemeris for PSR J1528-3146. A Bayesian analysis of the timing data was carried out to constrain the masses of the two components and the orientation of the orbit. We further analyzed the polarization properties of the pulsar, in order to constrain the orientations of the magnetic axis and of the line-of-sight with respect to the spin axis. We measured a significant rate of advance of periastron for the first time, and put constraints on the Shapiro delay in the system and on the rate of change of the projected semi-major axis of the pulsar's orbit. The Bayesian analysis yielded measurements for the pulsar and companion masses of respectively $M_p = 1.61_{-0.13}^{+0.14}$ M$_\odot$ and $M_c = 1.33_{-0.07}^{+0.08}$ M$_\odot$ (68\% C.L.), confirming that the companion is indeed massive. This companion mass as well as other characteristics of PSR J1528$-$3146 make this pulsar very similar to PSR J2222-0137, a 32.8 ms pulsar orbiting a WD whose heavy mass ($\sim 1.32$ M$_\odot$) was unique among pulsar-WD systems until now. Our measurements therefore suggest common evolutionary scenarios for PSRs J1528-3146 and J2222-0137.
A. Albert, R. Alfaro, J. C. Arteaga-Velázquez
et al.
Ground-based gamma-ray astronomy is still a rather young field of research, with strong historical connections to particle physics. This is why most observations are conducted by experiments with proprietary data and analysis software, as it is usual in the particle physics field. However in recent years, this paradigm has been slowly shifting towards the development and use of open-source data formats and tools, driven by upcoming observatories such as the Cherenkov Telescope Array (CTA). In this context, a community-driven, shared data format (the gamma-astro-data-format or GADF) and analysis tools such as Gammapy and ctools have been developed. So far these efforts have been led by the IACT community, leaving out other types of ground-based gamma-ray instruments.We aim to show that the data from ground particle arrays, such as the High-Altitude Water Cherenkov (HAWC) observatory, is also compatible with the GADF and can thus be fully analysed using the related tools, in this case Gammapy. We reproduce several published HAWC results using Gammapy and data products compliant with GADF standard. We also illustrate the capabilities of the shared format and tools by producing a joint fit of the Crab spectrum including data from six different gamma-ray experiments. We find excellent agreement with the reference results, a powerful check of both the published results and the tools involved. The data from particle detector arrays such as the HAWC observatory can be adapted to the GADF and thus analysed with Gammapy. A common data format and shared analysis tools allow multi-instrument joint analysis and effective data sharing. Given the complementary nature of pointing and wide-field instruments, this synergy will be distinctly beneficial for the joint scientific exploitation of future observatories such as the Southern Wide-field Gamma-ray Observatory and CTA.
We present the Automated Photometry Of Transients (AutoPhOT) package, a novel automated pipeline that is designed for rapid, publication-quality photometry of astronomical transients. AutoPhOT is built from the ground up using Python 3 - with no dependencies on legacy software. Capabilities of AutoPhOT include aperture and point-spread-function photometry, template subtraction, and calculation of limiting magnitudes through artificial source injection. AutoPhOT is also capable of calibrating photometry against either survey catalogues, or using a custom set of local photometric standards, and is designed primarily for ground-based optical and infrared images. We show that both aperture and point-spread-function photometry from AutoPhOT is consistent with commonly used software, for example DAOPHOT, and also demonstrate that AutoPhOT can reproduce published light curves for a selection of transients with minimal human intervention.
According to the current understanding of cosmic structure formation, the precursors of the most massive structures in the Universe began to form shortly after the Big Bang, in regions corresponding to the largest fluctuations in the cosmic density field. Observing these structures during their period of active growth and assembly—the first few hundred million years of the Universe—is challenging because it requires surveys that are sensitive enough to detect the distant galaxies that act as signposts for these structures and wide enough to capture the rarest objects. As a result, very few such objects have been detected so far. Here we report observations of a far-infrared-luminous object at redshift 6.900 (less than 800 million years after the Big Bang) that was discovered in a wide-field survey. High-resolution imaging shows it to be a pair of extremely massive star-forming galaxies. The larger is forming stars at a rate of 2,900 solar masses per year, contains 270 billion solar masses of gas and 2.5 billion solar masses of dust, and is more massive than any other known object at a redshift of more than 6. Its rapid star formation is probably triggered by its companion galaxy at a projected separation of 8 kiloparsecs. This merging companion hosts 35 billion solar masses of stars and has a star-formation rate of 540 solar masses per year, but has an order of magnitude less gas and dust than its neighbour and physical conditions akin to those observed in lower-metallicity galaxies in the nearby Universe. These objects suggest the presence of a dark-matter halo with a mass of more than 100 billion solar masses, making it among the rarest dark-matter haloes that should exist in the Universe at this epoch.
Evidências astrofísicas e cosmológicas sugerem que aproximadamente 85% da matéria no Universo é feita de um componente não luminoso e pouco interagente chamado de matéria escura. Várias sugestões para sua composição têm sido propostas, no entanto, até o momento não foi confirmada nenhuma detecção direta para esse tipo matéria. Áxions, partículas neutras muito leves e pouco interagentes, sugeridas na década de 1970 para resolver o problema da violação de CP na interação forte, podem constituir esta matéria misteriosa que tem desafiado toda a comunidade científica por várias décadas. Neste artigo, revisamos brevemente a motivação inicial, os modelos clássicos, a produção e as pesquisas experimentais sobre áxions.
Neste artigo, iremos revisar, de maneira não técnica, conceitos chaves para o entendimento do que são ondas gravitacionais. Com intuito de abarcar um amplo público, vamos discutir o que são ondas sonoras, ondas eletromagnéticas, a natureza da gravitação e ondas gravitacionais propriamente ditas. Abordaremos também alguns aspectos da detecção da primeira onda gravitacional e as consequências dessa grande conquista para a ciência e nosso conhecimento sobre o universo.