125 citations · 956 across the 20 of their papers we have counts for
20 papers
Explaining temporal variations in the jet position angle of the blazar OJ 287 using its binary black hole central engine model
Lankeswar Dey, Mauri J. Valtonen, A. Gopakumar +5
The bright blazar OJ 287 is the best-known candidate for hosting a supermassive black hole binary system. It inspirals due to the emission of nanohertz gravitational waves (GWs). O…
Spitzer Observations of the Predicted Eddington Flare from Blazar OJ 287
Seppo Laine, Lankeswar Dey, Mauri Valtonen +25
Binary black hole (BH) central engine description for the unique blazar OJ 287 predicted that the next secondary BH impact-induced bremsstrahlung flare should peak on 2019 July 31.…
MSTAR -- a fast parallelised algorithmically regularised integrator with minimum spanning tree coordinates
Antti Rantala, Pauli Pihajoki, Matias Mannerkoski +2
We present the novel algorithmically regularised integration method MSTAR for high accuracy () integrations of N-body systems using minimum spanning tree c…
Gravitational Waves from the Inspiral of Supermassive Black Holes in Galactic-scale Simulations
Matias Mannerkoski, Peter H. Johansson, Pauli Pihajoki +2
We study the orbital evolution and gravitational wave (GW) emission of supermassive black hole (SMBH) binaries formed in gas-free mergers of massive early-type galaxies using the h…
Barycentric interpolation on Riemannian and semi-Riemannian spaces
Pauli Pihajoki, Matias Mannerkoski, Peter H. Johansson
Interpolation of data represented in curvilinear coordinates and possibly having some non-trivial, typically Riemannian or semi-Riemannian geometry is an ubiquitous task in all of…
Accretion Disk Parameters determined from the great 2015 flare of OJ 287
Mauri J. Valtonen, Staszek Zola, Pauli Pihajoki +17
In the binary black hole model of OJ 287 the secondary black hole orbits a much more massive primary, and impacts on the primary accretion disk at predictable times. We update the…
The Unique Blazar OJ 287 and its Massive Binary Black Hole Central Engine
Lankeswar Dey, Achamveedu Gopakumar, Mauri Valtonen +12
The bright blazar OJ 287 is the best-known candidate for hosting a nanohertz gravitational wave (GW) emitting supermassive binary black hole (SMBBH) in the present observable unive…
Authenticating the Presence of a Relativistic Massive Black Hole Binary in OJ 287 Using its General Relativity Centenary Flare: Improved Orbital Parameters
Lankeswar Dey, M. J. Valtonen, A. Gopakumar +5
Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show…
General purpose ray-tracing and polarized radiative transfer in General Relativity
Pauli Pihajoki, Matias Mannerkoski, Joonas Nättilä +1
Ray-tracing is a central tool for constructing mock observations of compact object emission and for comparing physical emission models with observations. We present Arcmancer, a pu…
Radiation from rapidly rotating oblate neutron stars
Joonas Nättilä, Pauli Pihajoki
A theoretical framework for emission originating from rapidly rotating oblate compact objects is described in detail. By using a Hamilton-Jacobi formalism, we show how the special…
A geometric approach to non-linear correlations with intrinsic scatter
Pauli Pihajoki
We propose a new mathematical model for -dimensional non-linear correlations with intrinsic scatter in -dimensional data. The model is based on Riemannian geometry, and is…
Ray-tracing and polarized radiative transfer in General Relativity
Pauli Pihajoki, Antti Rantala, Peter H. Johansson
We discuss the problem of polarized radiative transfer in general relativity. We present a set of equations suitable for solving the problem numerically for the case of an arbitrar…
Post-Newtonian dynamical modeling of supermassive black holes in galactic-scale simulations
Antti Rantala, Pauli Pihajoki, Peter H. Johansson +3
We present KETJU, a new extension of the widely-used smoothed particle hydrodynamics simulation code GADGET-3. The key feature of the code is the inclusion of algorithmically regul…
Shaken and Stirred: The Milky Way's Dark Substructures
Till Sawala, Pauli Pihajoki, Peter H. Johansson +4
The predicted abundance and properties of the low-mass substructures embedded inside larger dark matter haloes differ sharply among alternative dark matter models. Too small to hos…
Black hole accretion disc impacts
Pauli Pihajoki
We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive…
Explicit methods in extended phase space for inseparable Hamiltonian problems
Pauli Pihajoki
We present a method for explicit leapfrog integration of inseparable Hamiltonian systems by means of an extended phase space. A suitably defined new Hamiltonian on the extended pha…
A helical jet model for OJ287
Mauri Valtonen, Pauli Pihajoki
Context. OJ287 is a quasar with a quasi-periodic optical light curve, with the periodicity observed for over 120 years. This has lead to a binary black hole model as a common expla…
Short time-scale periodicity in OJ 287
Pauli Pihajoki, Mauri Valtonen, Stefano Ciprini
We have studied short-term variations of the blazar OJ 287, suspected to host a supermassive black hole binary. In this study, we use a two-season optical R-band dataset from 2004-…
Precursor flares in OJ 287
P. Pihajoki, M. Valtonen, S. Zola +19
We have studied three most recent precursor flares in the light curve of the blazar OJ 287 while invoking the presence of a precessing binary black hole in the system to explain th…
The Sloan Great Wall. Rich clusters
M. Einasto, E. Tago, E. Saar +10
We present the results of the study of the substructure and galaxy content of ten rich clusters of galaxies in three different superclusters of the Sloan Great Wall. We determine t…