Search for gravitational radiation from intermediate mass black hole binaries in data from the second LIGO-Virgo joint science run

Abstract

and was sensitive to IMBHBs with a range up to ∼200 Mpc, averaged over the possible sky positions and inclinations of the binaries with respect to the line of sight. No significant candidate was found. Upper limits on the coalescence-rate density of nonspinning IMBHBs with total masses between 100 and 450 M ⊙ and mass ratios between 0.25 and 1 were placed by combining this analysis with an analogous search performed on data from the first LIGO-Virgo joint science run (November 2005-October 2007). The most stringent limit was set for systems consisting of two 88 M ⊙ black holes and is equal to 0.12 Mpc −3 Myr −1 at the 90% confidence level. This paper also presents the first estimate, for the case of an unmodeled analysis, of the impact on the search range of IMBHB spin configurations: the visible volume for IMBHBs with nonspinning components is roughly doubled for a population of IMBHBs with spins aligned with the binary's orbital angular momentum and uniformly distributed in the dimensionless spin parameter up to 0.8, whereas an analogous population with antialigned spins decreases the visible volume by ∼20%.

All-sky search for short gravitational-wave bursts in the first Advanced LIGO run

“…The first 16 days of coincident data have been already analyzed, resulting in a high-significance detection statement for the GW150914 event [7]. GW bursts can be generated by a wide variety of astrophysical sources, such as merging compact binary systems [8,9], core-collapse supernovae of massive stars [10], neutron stars collapsing to form black holes, pulsar glitches, and cosmic string cusps [11]. Some of these sources have dedicated targeted searches such as optically triggered core-collapse supernova [12] or GRB triggered searches [13].…”

Observing gravitational-wave transient GW150914 with minimal assumptions

“…The most recent cWB results from the initial detectors are [17,19,33]. The cWB algorithm has since been upgraded to conduct transient searches with the advanced detectors [24].…”

“…An important source of gravitational-wave transients are the mergers of binary black holes (BBH) [12][13][14]. Burst searches in data from the initial generation of interferometer detectors were sensitive to distant BBH signals from mergers with total masses in the range ∼20-400 M ⊙ [15,16]. Since burst methods do not require precise waveform models, the unmodeled search space may include BBH mergers with misaligned spins, large mass ratios, or eccentric orbits.…”

LIGO and the opening of a unique observational window on the universe

“…These sources include (i) compact binary coalescences-neutron star (NS) pairs (BNS or NSþNS), black-hole (BH) neutron systems (BHþNS), and black-hole pairs (BBHs or BHþBH)-having well-understood modeled frequencytime evolution of signal waveforms; (ii) transient burst sources without modeled waveforms [supernovae (SNe) and other shortduration waveforms]; (iii) continuous (essentially monochromatic) signals from rotating neutron stars having nonaxisymmetric deformations-the gravitational-wave counterparts to electromagnetic (EM) pulsars; and (iv) broadband stochastic gravitational-wave background detectable by its cross-power in the strain signals from pairs of detectors [this is the gravitationalwave counterpart to the cosmic microwave background (CMB) or coming from a population of unresolved distant sources falling into one or more of the previous three categories]. The observational upper limits on compact-object coalescence rates were of moderate astrophysical interest, although the upper limits for binary black holes came to within a factor of 2 greater than the most optimistic model predictions (24)(25)(26).…”