Optical Flares from the Tidal Disruption of Stars by Massive Black Holes

By L. Strubbe, E. Quataert. Proceedings of the International Astronomical Union, 2009

414 citations recorded by the source corpus.

A star that wanders too close to a massive black hole (BH) is shredded by the BH's tidal gravity. Stellar gas falls back to the BH, releasing a flare of energy. In anticipation of upcoming transient surveys, we predict the light curves and spectra of tidal flares as a function of time, highlighting the unique signatures of tidal flares in the optical and near-IR. Some of the gas initially bound to the BH is likely blown away when the fallback rate is super-Eddington at early times. This outflow produces an optical luminosity comparable to that of a supernova (Figure 1, left panel); such events have durations of ~ 10 days and may have been missed in supernova searches that exclude the nuclear regions of galaxies. When the fallback rate subsides below Eddington, the gas accretes onto the BH via a thin disk whose emission peaks in the UV to soft X-rays. Some of this emission is reprocessed by the unbound stellar debris, producing a spectrum of very broad emission lines, with no corresponding narrow forbidden lines (center panel). These lines are strongest for BHs with MBH ~ 105–106M⊙ and thus optical surveys are particularly sensitive to the lowest mass BHs in galactic nuclei. Calibrating our models to ROSAT and GALEX observations, we predict detection rates for Pan-STARRS, Palomar Transit Factory, and LSST (right panel) and highlight observational challenges in the optical. Pan-STARRS should detect at least several events per year — many more if current theoretical models of super-Eddington outflows are correct. These surveys will significantly improve our knowledge of stellar dynamics in galactic nuclei, the physics of super-Eddington accretion, the demography of intermediate mass BHs, and the role of tidal disruption in the growth of massive BHs.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/b2452229010719423bef67e6978bb55d81817c7b

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. B. Metzger
2. E. Berger
3. Bing Zhang
4. P. Hopkins
5. L. Hernquist
6. E. Quataert
7. Volker Springel
8. D. Schneider

Citations in the corpus

• Weighing Black Holes Using Tidal Disruption Events (2018, background): “…& Stone 2016), can help explain the observed emission by reprocessing the luminosity generated by the various dissipation processes at play (Loeb & Ulmer 1997; Ulmer et al. 1998; Bogdanović et al. 2004; Guillochon et al. 2014; Jiang et al. 2016; Coughlin & Begelman 2014; Strubbe & Quataert 2009).”
• Radio transients from stellar tidal disruption by massive black holes (2011, background): “The most tightly bound material returns on a timescale (e.g. Strubbe & Quataert 2009) tfallback ≃ 2π 63/2 ( Rp R⋆ )3/2 R3p GMBH 1/2 ≃ 5 ( MBH 107M⊙ )5/2 days, (2) where the last expression is evaluated for a solar-type star(R⋆ = R⊙) with a pericenter distanceRp = 6GMBH/c2 ∼ Rt.”
• ASASSN-15oi: a rapidly evolving, luminous tidal disruption event at 216 Mpc (2016, background): “…optical/UV emission is likely dominated by a photosphere formed within the stellar debris (Evans & Kochanek 1989; Loeb & Ulmer 1997; Ulmer 1999; Strubbe & Quataert 2009; Roth et al. 2015), and is likely dependent on the viewing angle (Guillochon, Manukian & Ramirez-Ruiz 2014; Metzger & Stone…”
• Swift J1644+57 gone MAD: the case for dynamically-important magnetic flux threading the black hole in a jetted tidal disruption event (2013, background): “When the accretion rate is superEddington at early times, the disk may be prone to outflows driven by radiation pressure (e.g. Ohsuga et al. 2005; Strubbe & Quataert 2009), in which case the accretion rate reaching the BH is less than Ṁfb.”
• THE ULTRAVIOLET-BRIGHT, SLOWLY DECLINING TRANSIENT PS1-11af AS A PARTIAL TIDAL DISRUPTION EVENT (2013, methodology): “Lodato & Rossi (2011) computed multiband light curves for the Lodato et al. (2009) models, including the effects of a wind (Strubbe & Quataert 2009).”
• The Cow: Discovery of a Luminous, Hot, and Rapidly Evolving Transient (2018, background): “…Ofek et al. 2010), cooling low-mass envelopes after a SN shock breakout (Nakar & Sari 2010; Kleiser & Kasen 2014), a magnetar-powered binary neutron star merger (Gao et al. 2013; Yu et al. 2013; Metzger & Piro 2014), and an optical flare from a tidal disruption event (Strubbe & Quataert 2009).”
• Disc formation from tidal disruptions of stars on eccentric orbits by Schwarzschild black holes (2015, methodology): “Many authors have assumed that the disc is geometrically thin or slim (Cannizzo & Gehrels 2009; Strubbe & Quataert 2009; Cannizzo, Troja & Lodato 2011; Lodato & Rossi 2011; Shen & Matzner 2014) using the standard α parametrization (Shakura & Sunyaev 1973).”
• LSST: From Science Drivers to Reference Design and Anticipated Data Products (2008, background): “• Search for stellar tidal disruptions by nuclear supermassive black holes (Evans & Kochanek 1989; Gezari et al. 2008; Strubbe & Quataert 2009; Bloom et al. 2011; Gezari 2012), as well as binary supermassive black holes in the in-spiral phase (e.g., Cuadra et al. 2009).”
• Revisiting Optical Tidal Disruption Events with iPTF16axa (2017, background): “10 7 M⊙, the initial stage of the accretion is expected to be super-Eddington (Strubbe & Quataert 2009; Lodato & Rossi 2011).”
• An Embedded X-Ray Source Shines through the Aspherical AT 2018cow: Revealing the Inner Workings of the Most Luminous Fast-evolving Optical Transients (2018, background): “…period (Yu et al. 2013; Metzger & Piro 2014; Hotokezaka et al. 2017), an accreting neutron star (NS; e.g., following a WD–NS merger; Margalit & Metzger 2016), or an accreting stellar-mass (Kashiyama & Quataert 2015) or supermassive black hole (BH; e.g., Strubbe & Quataert 2009; Cenko et al. 2012a).”
• The fast, luminous ultraviolet transient AT2018cow: extreme supernova, or disruption of a star by an intermediate-mass black hole? (2018, background): “While TDEs are expected to have super-Eddington mass fallback rates (e.g., Strubbe & Quataert 2009), the radiated luminosity is generally expected to be capped at close to the Eddington luminosity (Chen & Shen 2018), since higher luminosities would disrupt the accretion and drive the luminosity…”
• HYDRODYNAMICAL SIMULATIONS TO DETERMINE THE FEEDING RATE OF BLACK HOLES BY THE TIDAL DISRUPTION OF STARS: THE IMPORTANCE OF THE IMPACT PARAMETER AND STELLAR STRUCTURE (2012, background): “The conversion efficiency between mass accreted by the black hole and the light emitted is somewhat uncertain, and depends on factors such as the black hole’s spin and how the accretion rate compares to ṀEdd (Ulmer 1999; Beloborodov 1999; Strubbe & Quataert 2009; Lodato & Rossi 2010).”
• New Physical Insights about Tidal Disruption Events from a Comprehensive Observational Inventory at X-Ray Wavelengths (2016, background): “…be accreted onto the BH producing a luminous, short-lived accretion-powered flare (Lacy et al. 1982; Rees 1988; Evans & Kochanek 1989; Phinney 1989), which can emit above the Eddington Luminosity for a BH with MBH < 107M (Strubbe & Quataert 2009; Lodato & Rossi 2011; De Colle et al. 2012).”
• Multiband light curves of tidal disruption events (2010, methodology): “The main properties of a radiation-driven wind powered by fallback matter have been calculated by Rossi & Begelman (2009) and applied to the problem at hand by Strubbe & Quataert (2009).”
• DWARF GALAXIES WITH OPTICAL SIGNATURES OF ACTIVE MASSIVE BLACK HOLES (2013, background): “Finally, signatures of tidal disruptions of stars are strongest for low-mass BHs (e.g., Strubbe & Quataert 2009; Rosswog et al. 2009; Miller & Gültekin 2011) and ∼ 105 M BH mergers have the right frequency to provide a signal for future gravitational wave experiments (e.g., Hughes 2002).”
• PS1-10jh: THE DISRUPTION OF A MAIN-SEQUENCE STAR OF NEAR-SOLAR COMPOSITION (2013, methodology): “This combination of parameters is 17 close to the most common sub-Eddington disruption expected (De Colle et al. 2012), but predicts the black hole mass is a factor of a few larger than the black hole mass suggested by G12.”
• SYSTEMATICS OF DYNAMICAL MASS EJECTION, NUCLEOSYNTHESIS, AND RADIOACTIVELY POWERED ELECTROMAGNETIC SIGNALS FROM NEUTRON-STAR MERGERS (2013, background): “…the Palomar Transient Factory, the Synoptic All Sky InfraRed Survey, the Panoramic Survey Telescope and Rapid Response System, and the Large Synoptic Survey Telescope (see e.g. Strubbe & Quataert (2009) and Metzger & Berger (2012) for a compilation of certain characteristics of these facilities).”
• Rates of stellar tidal disruption as probes of the supermassive black hole mass function (2014, background): “Such disks are believed to drive mildly relativistic outflows, a process that has been modeled analytically (Blandford & Begelman 1999; Strubbe & Quataert 2009) and numerically (Ohsuga et al. 2005; Sadowski et al. 2014).”
• OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES (2010, methodology): “The fall-back rate is expected to follow a power-law of index −5/3 (Rees 1988; Phinney 1989), but see Lodato, King, & Pringle (2009) for predicted deviations from this canonical scaling; the light-curve does not in general show the same behavior, (e.g., Strubbe & Quataert 2009; Lodato & Rossi 2011).”