A5052239214- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Pulsars and Gravitational Waves Research
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Mechanics and Biomechanics Studies
- Astro and Planetary Science
- Relativity and Gravitational Theory
- Astrophysics and Star Formation Studies
- Cosmology and Gravitation Theories
- Particle Accelerators and Free-Electron Lasers
- High-pressure geophysics and materials
- Radio Astronomy Observations and Technology
- Geophysics and Gravity Measurements
- Nuclear physics research studies
- Black Holes and Theoretical Physics
- Scientific Research and Discoveries
- X-ray Spectroscopy and Fluorescence Analysis
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Computational Physics and Python Applications
- Scientific Measurement and Uncertainty Evaluation
University of Geneva
2015-2024
Global Social Observatory
2016-2020
University of Copenhagen
2018-2019
Center for Astrophysics Harvard & Smithsonian
2010-2016
Smithsonian Astrophysical Observatory
2013-2014
Foundation for Research and Technology Hellas
2014
Harvard University
2012-2013
San Diego State University
2010
Northwestern University
2006-2010
McMaster University
2010
Abstract The Laser Interferometer Space Antenna (LISA) will be a transformative experiment for gravitational wave astronomy, and, as such, it offer unique opportunities to address many key astrophysical questions in completely novel way. synergy with ground-based and space-born instruments the electromagnetic domain, by enabling multi-messenger observations, add further discovery potential of LISA. next decade is crucial prepare community LISA’s first observations. This review outlines...
We compute the expected X-ray diffuse background and radiative feedback on intergalactic medium (IGM) from binaries prior to during epoch of reionization. The cosmic evolution compact is followed using a population synthesis technique that treats separately neutron stars black hole in different spectral states calibrated reproduce observed properties galaxies at z ≲ 4. Together with an updated empirical determination history star formation, recent modeling stellar mass–metallicity relation,...
Abstract The second LIGO–Virgo catalog of gravitational-wave (GW) transients has more than quadrupled the observational sample binary black holes. We analyze this using a suite five state-of-the-art hole population models covering range isolated and dynamical formation channels infer branching fractions between as well constraints on uncertain physical processes that impact properties mergers. Given our set models, we find significant differences underlying detectable populations, diversity...
Context. After years of scientific progress, the origin stellar binary black holes is still a great mystery. Several formation channels for merging have been proposed in literature. As more merger detections are expected with future gravitational-wave observations, population synthesis studies can help to distinguish between them. Aims. We study coalescing via evolution isolated field binaries that go through common envelope phase order obtain combined distributions observables such as...
We study the impact of mass-transfer physics on observable properties binary black hole populations formed through isolated evolution. investigate mass-accretion efficiency onto compact objects and common-envelope observed distributions $\chi_{eff}$, $M_{chirp}$ $q$. find that low common envelope translates to tighter orbits post therefore more tidally spun up second-born holes. However, these systems have short merger timescales are only marginally detectable by current gravitational-waves...
Most massive stars are members of a binary or higher-order stellar systems, where the presence companion can decisively alter their evolution via interactions. Interacting binaries also important astrophysical laboratories for study compact objects. Binary population synthesis studies have been used extensively over last two decades to interpret observations compact-object and decipher physical processes that lead formation. Here, we present POSYDON, novel, code incorporates full...
Unusually high N/O abundance ratios were recently reported for a very compact, intensively star-forming object GN-z11 at $z=10.6$ from JWST/NIRSpec observations. We present an empirical comparison with the C, N, and O in Galactic globular clusters (GCs) over large metallicity range. show that hot hydrogen-burning nucleosynthesis within supermassive stars (SMS) formed through runaway collisions can consistently explain observed abundances ratio GCs. This suggests proto-globular cluster...
X-ray photons, because of their long mean-free paths, can easily escape the galactic environments where they are produced, and interact at distances with intergalactic medium, potentially having a significant contribution to heating reionization early universe. The two most important sources photons in universe active nuclei (AGNs) binaries (XRBs). In this Letter we use results from detailed, large scale population synthesis simulations study energy feedback XRBs, first galaxies (z ∼ 20)...
High redshift galaxies permit the study of formation and evolution X-ray binary populations on cosmological timescales, probing a wide range metallicities star-formation rates. In this paper, we present results from large scale population synthesis that models first universe until today. We use as input to our modeling Millennium II Cosmological Simulation updated semi-analytic galaxy catalog by Guo et al. (2011) self-consistently account for star history metallicity universe. Our modeling,...
Abstract Over 40 years of research suggests that the common envelope phase, in which an evolved star engulfs its companion upon expansion, is critical evolutionary stage forming short-period, compact-object binary systems, such as coalescing double compact objects, X-ray binaries, and cataclysmic variables. In this work, we adapt one-dimensional hydrodynamic stellar evolution code, MESA , to model inspiral a 1.4 M ⊙ neutron (NS) inside 12 red supergiant star. We self-consistently calculate...
We present measurements of the evolution normal-galaxy X-ray emission from $z \approx$ 0-7 using local galaxies and galaxy samples in 6 Ms Chandra Deep Field-South (CDF-S) survey. The majority CDF-S are observed at rest-frame energies above 2 keV, where is expected to be dominated by binary (XRB) populations; however, hot gas provide small contributions observed- frame < 1 keV 1$. show that a single scaling relation between luminosity ($L_{\rm X}$) star-formation rate (SFR) insufficient for...
We present new Chandra constraints on the X-ray luminosity functions (XLFs) of binary (XRB) populations, and their scaling relations, for a sample 38 nearby galaxies (D = 3.4-29 Mpc). Our galaxy is drawn primarily from Spitzer infrared survey (SINGS), contains wealth (5.8 Ms total) multiwavelength data, allowing star-formation rates (SFRs) stellar masses (M*) to be measured subgalactic scales. divided 2478 detected sources into 21 subsamples in bins specific-SFR (sSFR SFR/M*) constructed...
The origin of nebular HeII emission, which is frequently observed in low-metallicity (O/H) star-forming galaxies, remains largely an unsolved question. Using the anticorrelation integrated X-ray luminosity per unit star formation rate ($L_X/{\rm SFR}$) binary population with metallicity and other empirical data from well-studied galaxy I Zw 18, we show that 4686 intensity its trend naturally reproduced if bulk He$^+$ ionizing photons are emitted by sources. We also a combination models...
The formation of merging binary black holes can occur through multiple astrophysical channels such as, e.g., isolated evolution and dynamical or, alternatively, have a primordial origin. Increasingly large gravitational-wave catalogs black-hole mergers allowed for the first model selection studies between different theoretical predictions to constrain some their uncertainties branching ratios. In this work, we show how one could add an additional independent constraint by using stochastic...
Abstract Binaries harboring a millisecond pulsar (MSP) and black hole (BH) are key observing target for current upcoming surveys. We model the formation evolution of such binaries in isolation at solar metallicity using next-generation binary population synthesis code POSYDON . examine neutron star (NS)–BH where NS forms first (labeled NSBH), as must be able to spin up MSP rotation periods before BH these systems. find that NSBHs very rare have birth rate <1 Myr −1 Milky Way–like galaxy...
In recent years, an increasing number of proper motions have been measured for Galactic X-ray binaries. When supplemented with accurate determinations the component masses, orbital period, and donor effective temperature, these kinematical constraints harbor a wealth information on system's past evolution. Here, we consider all this available to reconstruct full evolutionary history black hole binary XTE J1118+480, assuming that system originated in disk has solar metallicity. This analysis...
In recent years, accurate observational constraints have become available for an increasing number of Galactic X-ray binaries (XRBs). Together with proper-motion measurements, we could reconstruct the full evolutionary history XRBs back to time compact object formation. this paper, present first study persistent source Cygnus X-1 that takes into account all constraints. Our analysis accounts three phases: orbital evolution and motion through potential after formation a black hole (BH),...
Galactic field black hole (BH) low-mass X-ray binaries (LMXBs) are believed to form in situ via the evolution of isolated binaries. In standard formation channel, these systems survived a common envelope phase, after which remaining helium core primary star and subsequently formed BH not expected be highly spinning. However, measured spins BHs LMXBs cover whole range spin parameters. We propose here that is acquired through accretion onto its formation. order test this hypothesis, we...
We present results from deep X-ray stacking of >4000 high-redshift galaxies z ≈ 1 to 8 using the 4 Ms Chandra Deep Field-South data, deepest survey extragalactic sky date. The galaxy samples were selected Lyman break technique based primarily on recent Hubble Space Telescope ACS and WFC3 observations. Based such high specific star formation rates (sSFRs): log SFR/M* > −8.7, we expect that observed properties these (LBGs) are dominated by young stellar populations. emission in LBGs,...
ABSTRACT Using the Chandra Source Catalog 2.0 and a newly compiled catalogue of galaxies in local Universe, we deliver census ultraluminous X-ray source (ULX) populations nearby galaxies. We find 629 ULX candidates 309 with distance smaller than 40 Mpc. The foreground/background contamination is $\sim \! 20{{\ \rm per\ cent}}$. bona fide star-forming scale on average star formation rate stellar mass (M⋆) such that number ULXs per galaxy $0.45^{+0.06}_{-0.09}\times \frac{\rm SFR}{\rm M_\odot...
Context . Various binary black hole formation channels have been proposed since the first gravitational event GW150914 was discovered by Advanced Laser Interferometer Gravitational-Wave Observatory (AdLIGO). The immediate progenitor of is a close system composed and helium star, which can be outcome classical isolated evolution through common envelope, or alternatively massive chemically homogeneous channel. Aims We study spin angular momentum star in order to constrain second-born hole....
The LIGO-Virgo collaboration recently reported the properties of GW190412, a binary black hole merger with unequal component masses (mass ratio $0.25^{+0.06}_{-0.04}$ when using EOBNR PHM approximant) and non-vanishing effective spin aligned orbital angular momentum. They used uninformative priors to infer that more massive had dimensionless magnitude between 0.17 0.59 at 90\% confidence. We argue that, within context isolated evolution, it is natural assume priori first-born, has negligible...
The existence of merging black hole-neutron star (BHNS) binaries has been ascertained through the observation their gravitational wave (GW) signals. However, to date, no definitive electromagnetic (EM) emission confidently associated with these mergers. Such an association could help unravel crucial information on systems, for example, BH spin distribution, equation state (EoS) neutron and rate heavy element production. We modeled multi-messenger (MM) from BHNS mergers detectable during...