Discovery of a Close-separation Binary Quasar at the Heart of a z ∼ 0.2 Merging Galaxy and Its Implications for Low-frequency Gravitational Waves

Goulding, Andy D.; Pardo, Kris; Greene, Jenny E.; Mingarelli, Chiara M. F.; Nyland, Kristina; Strauss, Michael A.

doi:10.3847/2041-8213/ab2a14

Cited by 58 publications

(39 citation statements)

References 57 publications

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“…The absolute number of TOAs, as well as the number of timing model parameters (including parameterizations of the noise), play a determining role in the time it takes to perform GW analyses of PTA data (van Haasteren & Vallisneri 2015, 2014Ellis et al 2013;Lentati et al 2013b). Advanced data analysis techniques to handle this deluge of TOAs will need to be significantly improved if we want to avoid delays on the numerous science deliverables offered by PTAs (Cordes et al 2019;Fonseca et al 2019;Goulding et al 2019;Kelley et al 2019;Lynch et al 2019;Mingarelli 2019;Siemens et al 2019;Stinebring et al 2019;Taylor et al 2019).…”

Section: ∼0mentioning

confidence: 99%

The NANOGrav 12.5 yr Data Set: Observations and Narrowband Timing of 47 Millisecond Pulsars

Alam¹,

Arzoumanian²,

Baker³

et al. 2020

ApJS

Self Cite

140

109

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We present a new analysis of the profile data from the 47 millisecond pulsars comprising the 12.5year data set of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), which is presented in a parallel paper (Alam et al. 2020, NG12.5). Our reprocessing is performed using "wideband" timing methods, which use frequency-dependent template profiles, simultaneous time-of-arrival (TOA) and dispersion measure (DM) measurements from broadband observations, and novel analysis techniques. In particular, the wideband DM measurements are used to constrain the DM portion of the timing model. We compare the ensemble timing results to NG12.5 by examining the timing residuals, timing models, and noise model components. There is a remarkable level of agreement across all metrics considered. Our best-timed pulsars produce encouragingly similar results to those from NG12.5. In certain cases, such as high-DM pulsars with profile broadening, or sources that are weak and scintillating, wideband timing techniques prove to be beneficial, leading to more precise timing model parameters by 10 − 15%. The high-precision, multi-band measurements of several pulsars indicate frequency-dependent DMs. Compared to the narrowband analysis in NG12.5, the TOA volume is reduced by a factor of 33, which may ultimately facilitate computational speed-ups for complex pulsar timing array analyses. This first wideband pulsar timing data set is a stepping stone, and its consistent results with NG12.5 assure us that such data sets are appropriate for gravitational wave analyses.

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Section: ∼0mentioning

confidence: 99%

The NANOGrav 12.5 yr Data Set: Observations and Narrowband Timing of 47 Millisecond Pulsars

Alam¹,

Arzoumanian²,

Baker³

et al. 2020

ApJS

Self Cite

140

109

View full text Add to dashboard Cite

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“…Massive black hole (BH) binaries, emitting nano-Hz GWs, are the most prominent IPTA sources (Burke-Spolaor et al 2019). Therefore, observational evidence for the existence of such binaries has important IPTA implications (Goulding et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Spitzer Observations of the Predicted Eddington Flare from Blazar OJ 287

Laine

Dey

Valtonen

et al. 2020

ApJL

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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. This prediction was based on detailed general relativistic modeling of the secondary BH trajectory around the primary BH and its accretion disk. The expected flare was termed the Eddington flare to commemorate the centennial celebrations of now-famous solar eclipse observations to test general relativity by Sir Arthur Eddington. We analyze the multi-epoch Spitzer observations of the expected flare between 2019 July 31 and 2019 September 6, as well as baseline observations during 2019 February-March. Observed Spitzer flux density variations during the predicted outburst time display a strong similarity with the observed optical pericenter flare from OJ287 during 2007 September. The predicted flare appears comparable to the 2007 flare after subtracting the expected higher base-level Spitzer flux densities at 3.55 and 4.49 μm compared to the optical R-band. Comparing the 2019 and 2007 outburst lightcurves and the previously calculated predictions, we find that the Eddington flare arrived within 4 hr of the predicted time. Our Spitzer observations are well consistent with the presence of a nano-Hertz gravitational-wave emitting spinning massive binary BH that inspirals along a general relativistic eccentric orbit in OJ287. These multi-epoch Spitzer observations provide a parametric constraint on the celebrated BH no-hair theorem. Unified Astronomy Thesaurus concepts: Gravitation (661); Black hole physics (159); BL Lacertae objects (158)

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“…Begelman et al 1980) has not been observed yet. But earlier steps have been explored, and several dual AGNs, which is a late stage of a galaxy merger (Genzel et al 2001;Koss et al 2016Koss et al , 2018Goulding et al 2019), or even a triple nucleus (Deane et al 2014;Pfeifle et al 2019), have been detected. While about 40% of ultra-luminous infrared galaxies exhibit a double nucleus (Cui et al 2001), Koss et al (2018) discuss that gas-rich luminous AGNs are often hidden mergers.…”

Section: Introductionmentioning

confidence: 99%

Double-peak emission line galaxies in the SDSS catalogue

Maschmann

Melchior

Mamon

et al. 2020

A&A

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Double-peak narrow emission line galaxies have been studied extensively in the past years, in the hope of discovering late stages of mergers. It is difficult to disentangle this phenomenon from disc rotations and gas outflows with the sole spectroscopic measurement of the central 3″. We aim to properly detect such galaxies and distinguish the underlying mechanisms with a detailed analysis of the host-galaxy properties and their kinematics. Relying on the Reference Catalogue of Spectral Energy Distribution, we developed an automated selection procedure and found 5663 double-peak emission line galaxies at z < 0.34 corresponding to 0.8% of the parent database. To characterise these galaxies, we built a single-peak no-bias control sample (NBCS) with the same redshift and stellar mass distributions as the double-peak sample (DPS). These two samples are indeed very similar in terms of absolute magnitude, [OIII] luminosity, colour-colour diagrams, age and specific star formation rate, metallicity, and environment. We find an important excess of S0 galaxies in the DPS, not observed in the NBCS, which cannot be accounted for by the environment, as most of these galaxies are isolated or in poor groups. Similarly, we find a relative deficit of pure discs in the DPS late-type galaxies, which are preferentially of Sa type. In parallel, we observe a systematic central excess of star formation and extinction for double peak (DP) galaxies. Finally, there are noticeable differences in the kinematics: The gas velocity dispersion is correlated with the galaxy inclination in the NBCS, whereas this relation does not hold for the DPS. Furthermore, the DP galaxies show larger stellar velocity dispersions and they deviate from the Tully-Fisher relation for both late-type and S0 galaxies. These discrepancies can be reconciled if one considers the two peaks as two different components. Considering the morphological biases in favour of bulge-dominated galaxies and the star formation central enhancement, we suggest a scenario of multiple, sequential minor mergers driving the increase of the bulge size, leading to larger fractions of S0 galaxies and a deficit of pure disc galaxies.

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Discovery of a Close-separation Binary Quasar at the Heart of a z ∼ 0.2 Merging Galaxy and Its Implications for Low-frequency Gravitational Waves

Cited by 58 publications

References 57 publications

The NANOGrav 12.5 yr Data Set: Observations and Narrowband Timing of 47 Millisecond Pulsars

The NANOGrav 12.5 yr Data Set: Observations and Narrowband Timing of 47 Millisecond Pulsars

Spitzer Observations of the Predicted Eddington Flare from Blazar OJ 287

Double-peak emission line galaxies in the SDSS catalogue

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