A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302-102?

D. J. D'Orazio, Z. Haiman, P. Duffell, B. D. Farris, A. I. MacFadyen

    Research output: Contribution to journalArticle

    Abstract

    Graham et al. have detected a 5.2 yr periodic optical variability of the quasar PG 1302-102 at redshift z = 0.3, which they interpret as the redshifted orbital period (1 + z)tbin of a putative supermassive black hole binary (SMBHB). Here, we consider the implications of a 3- 8 times shorter orbital period, suggested by hydrodynamical simulations of circumbinary discs (CBDs) with nearly equal-mass SMBHBs (q = M2/M1 ≳ 0.3). With the corresponding 2- 4 times tighter binary separation, PG 1302 would be undergoing gravitational wave dominated inspiral, and serve as a proof that the BHs can be fuelled and produce bright emission even in this late stage of the merger. The expected fraction of binaries with the shorter tbin, among bright quasars, would be reduced by one to two orders of magnitude, compared to the 5.2 yr period, in better agreement with the rarity of candidates reported by Graham et al. Finally, shorter periods would imply higher binary speeds, possibly imprinting periodicity on the light curves from relativistic beaming, as well as measurable relativistic effects on the Fe K a line. The CBD model predicts additional periodic variability on time-scales of tbin and ≈0.5tbin, as well as periodic variation of broad line widths and offsets relative to the narrow lines, which are consistent with the observations. Future observations will be able to test these predictions and hence the binary+CBD hypothesis for PG 1302.

    Original languageEnglish (US)
    Pages (from-to)2540-2545
    Number of pages6
    JournalMonthly Notices of the Royal Astronomical Society
    Volume452
    Issue number3
    DOIs
    StatePublished - Oct 27 2015

    Fingerprint

    imprinting
    rarity
    merger
    quasars
    periodicity
    timescale
    orbitals
    periodic variations
    prediction
    simulation
    relativistic effects
    gravitational waves
    light curve
    predictions
    effect
    test
    speed

    Keywords

    • Accretion, accretion discs
    • Quasars: individual: PG 1302

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302-102? / D'Orazio, D. J.; Haiman, Z.; Duffell, P.; Farris, B. D.; MacFadyen, A. I.

    In: Monthly Notices of the Royal Astronomical Society, Vol. 452, No. 3, 27.10.2015, p. 2540-2545.

    Research output: Contribution to journalArticle

    D'Orazio, D. J. ; Haiman, Z. ; Duffell, P. ; Farris, B. D. ; MacFadyen, A. I. / A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302-102?. In: Monthly Notices of the Royal Astronomical Society. 2015 ; Vol. 452, No. 3. pp. 2540-2545.
    @article{28ec2e1e7bb74fc4a72b298d1d635380,
    title = "A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302-102?",
    abstract = "Graham et al. have detected a 5.2 yr periodic optical variability of the quasar PG 1302-102 at redshift z = 0.3, which they interpret as the redshifted orbital period (1 + z)tbin of a putative supermassive black hole binary (SMBHB). Here, we consider the implications of a 3- 8 times shorter orbital period, suggested by hydrodynamical simulations of circumbinary discs (CBDs) with nearly equal-mass SMBHBs (q = M2/M1 ≳ 0.3). With the corresponding 2- 4 times tighter binary separation, PG 1302 would be undergoing gravitational wave dominated inspiral, and serve as a proof that the BHs can be fuelled and produce bright emission even in this late stage of the merger. The expected fraction of binaries with the shorter tbin, among bright quasars, would be reduced by one to two orders of magnitude, compared to the 5.2 yr period, in better agreement with the rarity of candidates reported by Graham et al. Finally, shorter periods would imply higher binary speeds, possibly imprinting periodicity on the light curves from relativistic beaming, as well as measurable relativistic effects on the Fe K a line. The CBD model predicts additional periodic variability on time-scales of tbin and ≈0.5tbin, as well as periodic variation of broad line widths and offsets relative to the narrow lines, which are consistent with the observations. Future observations will be able to test these predictions and hence the binary+CBD hypothesis for PG 1302.",
    keywords = "Accretion, accretion discs, Quasars: individual: PG 1302",
    author = "D'Orazio, {D. J.} and Z. Haiman and P. Duffell and Farris, {B. D.} and MacFadyen, {A. I.}",
    year = "2015",
    month = "10",
    day = "27",
    doi = "10.1093/mnras/stv1457",
    language = "English (US)",
    volume = "452",
    pages = "2540--2545",
    journal = "Monthly Notices of the Royal Astronomical Society",
    issn = "0035-8711",
    publisher = "Oxford University Press",
    number = "3",

    }

    TY - JOUR

    T1 - A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302-102?

    AU - D'Orazio, D. J.

    AU - Haiman, Z.

    AU - Duffell, P.

    AU - Farris, B. D.

    AU - MacFadyen, A. I.

    PY - 2015/10/27

    Y1 - 2015/10/27

    N2 - Graham et al. have detected a 5.2 yr periodic optical variability of the quasar PG 1302-102 at redshift z = 0.3, which they interpret as the redshifted orbital period (1 + z)tbin of a putative supermassive black hole binary (SMBHB). Here, we consider the implications of a 3- 8 times shorter orbital period, suggested by hydrodynamical simulations of circumbinary discs (CBDs) with nearly equal-mass SMBHBs (q = M2/M1 ≳ 0.3). With the corresponding 2- 4 times tighter binary separation, PG 1302 would be undergoing gravitational wave dominated inspiral, and serve as a proof that the BHs can be fuelled and produce bright emission even in this late stage of the merger. The expected fraction of binaries with the shorter tbin, among bright quasars, would be reduced by one to two orders of magnitude, compared to the 5.2 yr period, in better agreement with the rarity of candidates reported by Graham et al. Finally, shorter periods would imply higher binary speeds, possibly imprinting periodicity on the light curves from relativistic beaming, as well as measurable relativistic effects on the Fe K a line. The CBD model predicts additional periodic variability on time-scales of tbin and ≈0.5tbin, as well as periodic variation of broad line widths and offsets relative to the narrow lines, which are consistent with the observations. Future observations will be able to test these predictions and hence the binary+CBD hypothesis for PG 1302.

    AB - Graham et al. have detected a 5.2 yr periodic optical variability of the quasar PG 1302-102 at redshift z = 0.3, which they interpret as the redshifted orbital period (1 + z)tbin of a putative supermassive black hole binary (SMBHB). Here, we consider the implications of a 3- 8 times shorter orbital period, suggested by hydrodynamical simulations of circumbinary discs (CBDs) with nearly equal-mass SMBHBs (q = M2/M1 ≳ 0.3). With the corresponding 2- 4 times tighter binary separation, PG 1302 would be undergoing gravitational wave dominated inspiral, and serve as a proof that the BHs can be fuelled and produce bright emission even in this late stage of the merger. The expected fraction of binaries with the shorter tbin, among bright quasars, would be reduced by one to two orders of magnitude, compared to the 5.2 yr period, in better agreement with the rarity of candidates reported by Graham et al. Finally, shorter periods would imply higher binary speeds, possibly imprinting periodicity on the light curves from relativistic beaming, as well as measurable relativistic effects on the Fe K a line. The CBD model predicts additional periodic variability on time-scales of tbin and ≈0.5tbin, as well as periodic variation of broad line widths and offsets relative to the narrow lines, which are consistent with the observations. Future observations will be able to test these predictions and hence the binary+CBD hypothesis for PG 1302.

    KW - Accretion, accretion discs

    KW - Quasars: individual: PG 1302

    UR - http://www.scopus.com/inward/record.url?scp=84942010533&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84942010533&partnerID=8YFLogxK

    U2 - 10.1093/mnras/stv1457

    DO - 10.1093/mnras/stv1457

    M3 - Article

    AN - SCOPUS:84942010533

    VL - 452

    SP - 2540

    EP - 2545

    JO - Monthly Notices of the Royal Astronomical Society

    JF - Monthly Notices of the Royal Astronomical Society

    SN - 0035-8711

    IS - 3

    ER -