Searching for Asymmetric and Heavily Precessing Binary Black Holes in the Gravitational Wave Data from the LIGO Third Observing Run.

Leveraging the features of the GstLAL pipeline, we present the results of a matched filtering search for asymmetric binary black hole systems with heavily misaligned spins in LIGO and Virgo data taken during the third observing run. Our target systems show strong imprints of precession whereas current searches have nonoptimal sensitivity in detecting them. After measuring the sensitivity improvement brought by our search over standard spin-aligned searches, we report the detection of 30 gravitational wave events already discovered in the latest version of the Gravitational Wave Transient Catalog.

The complex circumstellar environment of supernova 2023ixf.

The early evolution of a supernova (SN) can reveal information about the environment and the progenitor star. When a star explodes in vacuum, the first photons to escape from its surface appear as a brief, hours-long shock-breakout flare, followed by a cooling phase of emission. However, for stars exploding within a distribution of dense, optically thick circumstellar material (CSM), the first photons escape from the material beyond the stellar edge and the duration of the initial flare can extend to several days, during which the escaping emission indicates photospheric heating.

Detection of stellar light from quasar host galaxies at redshifts above 6.

The detection of starlight from the host galaxies of quasars during the reionization epoch (z > 6) has been elusive, even with deep Hubble Space Telescope observations. The current highest redshift quasar host detected, at z = 4.5, required the magnifying effect of a foreground lensing galaxy.

Compact [C II] emitters around a C IV absorption complex at redshift 5.7.

The physical conditions of the circumgalactic medium are investigated by means of intervening absorption-line systems in the spectrum of background quasi-stellar objects (QSOs) out to the epoch of cosmic reionization. A correlation between the ionization state of the absorbing gas and the nature of the nearby galaxies has been suggested by the sources detected in either Lyα or [C II] 158 μm near to, respectively, highly ionized and neutral absorbers. This is also probably linked to the global changes in the incidence of absorption systems of different types and the process of cosmic reionization.

A shared accretion instability for black holes and neutron stars.

Accretion disks around compact objects are expected to enter an unstable phase at high luminosity. One instability may occur when the radiation pressure generated by accretion modifies the disk viscosity, resulting in the cyclic depletion and refilling of the inner disk on short timescales. Such a scenario, however, has only been quantitatively verified for a single stellar-mass black hole.

Vela pulsar wind nebula X-rays are polarized to near the synchrotron limit.

Pulsar wind nebulae are formed when outflows of relativistic electrons and positrons hit the surrounding supernova remnant or interstellar medium at a shock front. The Vela pulsar wind nebula is powered by a young pulsar (B0833-45, aged 11,000 years) and located inside an extended structure called Vela X, which is itself inside the supernova remnant. Previous X-ray observations revealed two prominent arcs that are bisected by a jet and counter jet.

Polarized blazar X-rays imply particle acceleration in shocks.

Most of the light from blazars, active galactic nuclei with jets of magnetized plasma that point nearly along the line of sight, is produced by high-energy particles, up to around 1 TeV. Although the jets are known to be ultimately powered by a supermassive black hole, how the particles are accelerated to such high energies has been an unanswered question. The process must be related to the magnetic field, which can be probed by observations of the polarization of light from the jets.

Kinematic Signatures of Impulsive Supernova Feedback in Dwarf Galaxies.

Impulsive supernova feedback and nonstandard dark matter models, such as self-interacting dark matter (SIDM), are the two main contenders for the role of the dominant core formation mechanism at the dwarf galaxy scale. Here we show that the impulsive supernova cycles that follow episodes of bursty star formation leave distinct features in the distribution function of stars: groups of stars with similar ages and metallicities develop overdense shells in phase space. If cores are formed through supernova feedback, we predict the presence of such features in star-forming dwarf galaxies with cored host halos.

Suppression of black-hole growth by strong outflows at redshifts 5.8-6.6.

Bright quasars, powered by accretion onto billion-solar-mass black holes, already existed at the epoch of reionization, when the Universe was 0.5-1 billion years old. How these black holes formed in such a short time is the subject of debate, particularly as they lie above the correlation between black-hole mass and galaxy dynamical mass in the local Universe.

A repeating fast radio burst source in a globular cluster.

Fast radio bursts (FRBs) are flashes of unknown physical origin. The majority of FRBs have been seen only once, although some are known to generate multiple flashes. Many models invoke magnetically powered neutron stars (magnetars) as the source of the emission.

Reverberation mapping of active galactic nuclei: from X-ray corona to dusty torus.

The central engines of active galactic nuclei (AGNs) are powered by accreting supermassive black holes, and while AGNs are known to play an important role in galaxy evolution, the key physical processes occur on scales that are too small to be resolved spatially (aside from a few exceptional cases). Reverberation mapping is a powerful technique that overcomes this limitation by using echoes of light to determine the geometry and kinematics of the central regions. Variable ionizing radiation from close to the black hole drives correlated variability in surrounding gas/dust but with a time delay due to the light travel time between the regions, allowing reverberation mapping to effectively replace spatial resolution with time resolution.

X-ray quasi-periodic eruptions from two previously quiescent galaxies.

Quasi-periodic eruptions (QPEs) are very-high-amplitude bursts of X-ray radiation recurring every few hours and originating near the central supermassive black holes of galactic nuclei. It is currently unknown what triggers these events, how long they last and how they are connected to the physical properties of the inner accretion flows. Previously, only two such sources were known, found either serendipitously or in archival data, with emission lines in their optical spectra classifying their nuclei as hosting an actively accreting supermassive black hole.

Constraints on Axionlike Particles from a Hard X-Ray Observation of Betelgeuse.

We use the first observation of Betelgeuse in hard x rays to perform a novel search for axionlike particles (ALPs). Betelgeuse is not expected to be a standard source of x rays, but light ALPs produced in the stellar core could be converted back into photons in the Galactic magnetic field, producing a detectable flux that peaks in the hard x-ray band (E_{γ}>10  keV). Using a 50 ks observation of Betelgeuse by the NuSTAR satellite telescope, we find no significant excess of events above the expected background.

A repeating fast radio burst source localized to a nearby spiral galaxy.

Fast radio bursts (FRBs) are brief, bright, extragalactic radio flashes. Their physical origin remains unknown, but dozens of possible models have been postulated. Some FRB sources exhibit repeat bursts.

The corona contracts in a black-hole transient.

The geometry of the accretion flow around stellar-mass black holes can change on timescales of days to months. When a black hole emerges from quiescence (that is, it 'turns on' after accreting material from its companion) it has a very hard (high-energy) X-ray spectrum produced by a hot corona positioned above its accretion disk, and then transitions to a soft (lower-energy) spectrum dominated by emission from the geometrically thin accretion disk, which extends to the innermost stable circular orbit. Much debate persists over how this transition occurs and whether it is driven largely by a reduction in the truncation radius of the disk or by a reduction in the spatial extent of the corona.

Variability Timescale and Spectral Index of Sgr A* in the Near Infrared: Approximate Bayesian Computation Analysis of the Variability of the Closest Supermassive Black Hole.

Sagittarius A* (Sgr A*) is the variable radio, near-infrared (NIR), and X-ray source associated with accretion onto the Galactic center black hole. We present an analysis of the most comprehensive NIR variability data set of Sgr A* to date: eight 24 hr epochs of continuous monitoring of Sgr A* at 4.5 m with the IRAC instrument on the , 93 epochs of 2.

and GBM Observations of the First Galactic Ultraluminous X-ray Pulsar Swift J0243.6+6124.

Swift J0243.6+6124 is a newly discovered Galactic Be/X-ray binary, revealed in late September 2017 in a giant outburst with a peak luminosity of 2 × 10(/7 kpc) erg s (0.1-10 keV), with no formerly reported activity.

LISA Sources in Milky Way Globular Clusters.

We explore the formation of double-compact-object binaries in Milky Way (MW) globular clusters (GCs) that may be detectable by the Laser Interferometer Space Antenna (LISA). We use a set of 137 fully evolved GC models that, overall, effectively match the properties of the observed GCs in the MW. We estimate that, in total, the MW GCs contain ∼21 sources that will be detectable by LISA.

STAR FORMATION AT = 2.481 IN THE LENSED GALAXY SDSS J1110+6459: STAR FORMATION DOWN TO 30 PARSEC SCALES.

We present measurements of the surface density of star formation, the star-forming clump luminosity function, and the clump size distribution function, for the lensed galaxy SGAS J111020.0+645950.8 at a redshift of =2.