OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES

By Sanne G M van Velzen, G. Farrar, S. Gezari, N. Morrell, Dennis Zaritsky, L. Östman, Mathew Smith, J. Gelfand, A. Drake. 2010

241 citations recorded by the source corpus.

Using archival Sloan Digital Sky Survey (SDSS) multi-epoch imaging data (Stripe 82), we have searched for the tidal disruption of stars by supermassive black holes in non-active galaxies. Two candidate tidal disruption events (TDEs) are identified. The TDE flares have optical blackbody temperatures of 2 × 104 K and observed peak luminosities of Mg = −18.3 and −20.4 (νLν = 5 × 1042, 4 × 1043 erg s−1, in the rest frame); their cooling rates are very low, qualitatively consistent with expectations for tidal disruption flares. The properties of the TDE candidates are examined using (1) SDSS imaging to compare them to other flares observed in the search, (2) UV emission measured by GALEX, and (3) spectra of the hosts and of one of the flares. Our pipeline excludes optically identifiable AGN hosts, and our variability monitoring over nine years provides strong evidence that these are not flares in hidden AGNs. The spectra and color evolution of the flares are unlike any SN observed to date, their strong late-time UV emission is particularly distinctive, and they are nuclear at high resolution arguing against these being first cases of a previously unobserved class of SNe or more extreme examples of known SN types. Taken together, the observed properties are difficult to reconcile with an SN or an AGN-flare explanation, although an entirely new process specific to the inner few hundred parsecs of non-active galaxies cannot be excluded. Based on our observed rate, we infer that hundreds or thousands of TDEs will be present in current and next-generation optical synoptic surveys. Using the approach outlined here, a TDE candidate sample with O(1) purity can be selected using geometric resolution and host and flare color alone, demonstrating that a campaign to create a large sample of TDEs, with immediate and detailed multi-wavelength follow-up, is feasible. A by-product of this work is quantification of the power spectrum of extreme flares in AGNs.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/75bbe5a81e47c2a6f3ac6868564afb84980aa86a

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. E. Berger
2. B. Metzger
3. Bing Zhang
4. W. Fong
5. S. Smartt
6. Ryan Chornock
7. T. Thompson
8. E. Quataert

In Instrumentation

1. S. Smartt
2. E. Berger
3. C. Kochanek
4. Krzysztof Zbigniew Stanek
5. A. Riess
6. T. Thompson
7. N. Smith
8. W. Fong

Citations in the corpus

• Consequences of Strong Compression in Tidal Disruption Events (2012, background): “…candidates have been observed, with most detections made in X-ray (Bade, Komossa & Dahlem 1996; Komossa & Greiner 1999; Gezari et al. 2003) or UV (Gezari et al. 2006, 2008, 2009), but some in optical archival (van Velzen et al. 2011) and transient (Cenko et al. 2012a; Gezari et al. 2012) searches.”
• Disc formation from tidal disruptions of stars on eccentric orbits by Schwarzschild black holes (2015, background): “A handful E-mail: bonnerot@strw.leidenuniv.nl of candidate TDEs have been detected so far in these bands (e.g. Komossa et al. 2004; Esquej et al. 2008; Gezari et al. 2009; van Velzen et al. 2011; Zauderer et al. 2011).”
• ASASSN-14ae: a tidal disruption event at 200 Mpc (2014, methodology): “While the X-ray candidates currently outnumber the optical and UV candidates, variable AGN activity can also mimic the behavior expected for TDEs in the X-ray, making it difficult to disentangle true TDEs from AGN (van Velzen et al. 2011).”
• Observational evidence for intermediate-mass black holes (2017, background): “…most TDEs (∼50; Komossa 2015) have been associated with SMBHs (e.g., Komossa & Bade 1999; Halpern et al. 2004; Lin et al. 2011, 2015; van Velzen et al. 2011; Cenko et al. 2012; Gezari et al. 2012; Saxton et al. 2012, 2017; Chornock et al. 2014; Holoien et al. 2014; Vinkó et al. 2015;…”
• Revisiting Optical Tidal Disruption Events with iPTF16axa (2017, methodology): “…and optical sky surveys with well-sampled optical light curves: D1-9 and D3-13 from GALEX+CFHTLS (Gezari et al. 2008), TDE1 and TDE2 from SDSS (van Velzen et al. 2011), PTF09ge from PTF (Arcavi et al. 2014), PS1-10jh (Gezari et al. 2012), and PS1-11af (Chornock et al. 2014) from…”
• Rates of stellar tidal disruption as probes of the supermassive black hole mass function (2014, background): “Approximately two dozen of these tidal disruption events (TDEs) have been observed, found with a diverse mixture of optical (van Velzen et al. 2011; Cenko et al. 2012a; Gezari et al. 2012; Arcavi et al. 2014; Chornock et al. 2014), UV (Gezari et al. 2006, 2008, 2009), X-ray (Bade et al. 1996;…”
• Weighing Black Holes Using Tidal Disruption Events (2018, background): “…(Holoien et al. 2016b; Brown et al. 2017), ASASSN-15oi (Holoien et al. 2016a), ASASSN-14ae (Holoien et al. 2014; Brown et al. 2016), OGLE16aaa (Wyrzykowski et al. 2017), D1-9 (Gezari et al. 2008), D3-13 (Gezari et al. 2008), TDE1 (van Velzen et al. 2011), and TDE2 (van Velzen et al. 2011).”
• THE ULTRAVIOLET-BRIGHT, SLOWLY DECLINING TRANSIENT PS1-11af AS A PARTIAL TIDAL DISRUPTION EVENT (2013, background): “Our photometry does not extend sufficiently blue to cover the SDSS u′ band so we cannot directly compare our measurements to the observerframe quantities used by van Velzen et al. (2011a).”
• Six months of multiwavelength follow-up of the tidal disruption candidate asassn-14li and implied tde rates from asas-sn (2015, background): “…Holoien et al. 2014a), the Palomar Transient Factory (PTF10iya, Cenko et al. 2012a; PTF09ge, PTF09axc, and PTF09djl, Arcavi et al. 2014), Pan-STARRS (PS1-10jh, Gezari et al. 2012; PS1-11af, Chornock et al. 2014), and the Sloan Digital Sky Survey (TDE 1 and TDE 2, van Velzen et al. 2011).”
• PS16dtm: A Tidal Disruption Event in a Narrow-line Seyfert 1 Galaxy (2017, background): “…GalYam 2012; Nicholl et al. 2015) with hydrogen (Type II) and without hydrogen (Type I) and tidal disruption events (TDEs; Gezari et al. 2009; van Velzen et al. 2011; Chornock et al. 2014; Komossa 2015), as well as some events that defy a clear classification (e.g. ASASSN-15lh; Dong et al. 2016;…”
• Finite, Intense Accretion Bursts from Tidal Disruption of Stars on Bound Orbits (2012, background): “A smaller number of strong TDE candidates have been found at optical wavelengths (van Velzen et al. 2011; Gezari et al. 2012).”
• 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): “…which the peak of the accretion rate is clearly observed (Gezari et al. 2012), but both n(t) and n∞ are measurable for flares that are observed long after peak (Komossa & Greiner 1999; Komossa et al. 2004; Gezari et al. 2006, 2008; Cappelluti et al. 2009; van Velzen et al. 2011; Cenko et al. 2012).”
• A CONTINUUM OF H- TO He-RICH TIDAL DISRUPTION CANDIDATES WITH A PREFERENCE FOR E+A GALAXIES (2014, methodology): “Van Velzen et al. (2011) rejected a few of their TDE candidates as AGN based on photometric variability beyond the season containing the flare.”
• Swift J1112.2−8238: a candidate relativistic tidal disruption flare (2015, background): “A number of TDF candidates have been found in the UV (e.g. Gezari et al. 2008, 2009, 2012), soft X-rays (e.g. Brandt, Pounds, & Fink 1995; Grupe et al. 1995; Bade, Komossa, & Dahlem 1996; Cappelluti et al. 2009) and the optical (e.g. van Velzen et al. 2011; Cenko et al. 2012; Arcavi et al. 2014).”
• Tidal Disruption Events (2013, methodology): “Before the first real-time searches for TDEs from optical time domain data, van Velzen et al. (2011) performed an archival study of the 300 deg2 SDSS Stripe 82 survey with the 2.5m telescope at Apache Point Observatory multi-epoch data to search for nuclear transients in inactive galaxy hosts.”
• A bright year for tidal disruptions (2015, methodology): “…mass and spin evolution of low-mass BHs. Theoretically (observationally) calculated TDE rates Ṅ ∼ 10−4 (10−5) gal−1 yr−1 (cf. Stone & Metzger 2014, van Velzen et al. 2011) imply that BHs with M• ∼< 10 6 M (105 M ) should see significant growth from star capture over a Hubble time, and may even…”