Multiband light curves of tidal disruption events
By G. Lodato, Elena Rossi Dipartimento di Fisica, U. Milano, I. R. I. O. Physics, The Hebrew University, Jérusalem, Israel. 2010
201 citations recorded by the source corpus.
Unambiguous detection of the tidal disruption of a star would allow an assessment of the presence and masses of supermassive black holes in quiescent galaxies. It would also provide invaluable information on bulge-scale stellar processes (such as two-body relaxation) via the rate at which stars are injected into the tidal sphere of influence of the black holes. This rate, in turn, is essential to predict gravitational radiation emission by compact object inspirals. The signature of a tidal disruption event is thought to be a fallback rate for the stellar debris on to the black hole that decreases as t -5/3 . This mass flux is often assumed to yield a luminous signal that decreases in time at the same rate. In this paper, we calculate the monochromatic light curves arising from such an accretion event. Differently from previous studies, we adopt a more realistic description of the fallback rate and of the super-Eddington accretion physics. We also provide simultaneous light curves in optical, ultraviolet (UV) and X-rays. We show that, after a few months, optical and UV light curves scale as t -5/12 , and are thus substantially flatter than the t -5/3 behaviour, which is a prerogative of the bolometric light curve, only. At earlier times and for black hole masses < 10 7 M ⊙ , the wind emission dominates: after reaching a peak of 10 41 -10 43 erg s -1 at roughly a month, the light curve decreases steeply as ~t -2.6 , until the disc contribution takes over. The X-ray band, instead, is the best place to detect the t -5/3 'smoking gun' behaviour, although it is displayed only for roughly a year, before the emission steepens exponentially.
Subfields: Astronomy and Astrophysics
View Paper: https://www.semanticscholar.org/paper/66192573ca833349f5f4aa3c2788b6659b7d9ad5
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Citations in the corpus
- Now You See It, Now You Don't: The Disappearing Central Engine of the Quasar J1011+5442 (2015, background): “In fact, Lodato & Rossi (2011) predict different power-law indices for light curves in different electromagnetic bands.”
- Consequences of Strong Compression in Tidal Disruption Events (2012, methodology): “If we first consider UV or soft X-ray surveys sensitive to the peak frequencies of TDE disc emission, then the peak luminosity L ∝ Ṁpeak ∝ β3n/2, implying a survey horizon rhor ∝ β3n/4 and a detection rate Ṅdet ∝ β (9n−4)/4.”
- A bright year for tidal disruptions (2015, methodology): “…− 0.1 of the initially bound stellar debris ends up reaching the inner circular disk and accreting onto the BH, with the remainder (comprising roughly half of the original star) blown out in a wind or unbound stream (Strubbe & Quataert 2009; Lodato & Rossi 2011) that rapidly comes to encase the BH.”
- Finite, Intense Accretion Bursts from Tidal Disruption of Stars on Bound Orbits (2012, background): “L ∝ Ṁ), although here the theoretical evidence is less clear (Lodato & Rossi 2011).”
- Six months of multiwavelength follow-up of the tidal disruption candidate asassn-14li and implied tde rates from asas-sn (2015, background): “…flare will be proportional to the rate of return of the stellar material to pericenter, but the exact return rates depend on the complex physics associated with the evolution of the accretion stream (e.g., Kochanek 1994; Lodato & Rossi 2011; Guillochon & Ramirez-Ruiz 2015; Shiokawa et al. 2015).”
- Swift J1112.2−8238: a candidate relativistic tidal disruption flare (2015, background): “…the disc point to a more complex picture, in which the t−5/3 decline is only present in certain bands and over a rather restricted range of time (Lodato & Rossi 2011), while even more recent calculations suggest that the t−2.2 decay seen in Swift J2058+0516 should be present in half of…”
- Tidal Disruption Events (2013, background): “This presents the possibility that the “mode” of the accretion flow will be vastly different for black holes of different mass, with black holes less than 3 × 107M in the super-Eddington regime, and above 3 × 107M in the sub-Eddington regime (Strubbe & Quataert 2009; Lodato & Rossi 2011; Metzger & S”
- ASASSN-14ae: a tidal disruption event at 200 Mpc (2014, methodology): “This differs from most TDE models where the luminosity evolution is described as a power law t−x with x ' 5/12 − 5/3 (e.g., Strubbe & Quataert 2009; Lodato & Rossi 2011).”
- Disc formation from tidal disruptions of stars on eccentric orbits by Schwarzschild black holes (2015, methodology): “Remarkably, it is comparable to or higher than the peak luminosity in the soft X-ray band from the viscous accretion through the disc (Lodato & Rossi 2011).”
- ASASSN-15oi: a rapidly evolving, luminous tidal disruption event at 216 Mpc (2016, background): “…physical parameters, including the depth of the encounter, the composition of the star, the fraction of the star that is accreted, and the geometry of the accretion stream (e.g., Kochanek 1994; Lodato & Rossi 2011; Guillochon & Ramirez-Ruiz 2015; Metzger & Stone 2015; Shiokawa et al. 2015).”