Wednesday, November 19, Years of Chandra: Chandra and the X-ray View of TDEs, Peter Maksym 1 Chandra and the X-ray View of Tidal Disruption Events Peter Maksym University Left: A1795 X-ray/optical CXO/Maksym et al./Donato et al press release, 2014; Right: Maksym et al. 2013

Wednesday, November 19, Years of Chandra: Chandra and the X-ray View of TDEs, Peter Maksym 2

Wednesday, November 19, Years of Chandra: Chandra and the X-ray View of TDEs, Peter Maksym 3 X-ray Selection and Follow-up

Wednesday, November 19, Years of Chandra: Chandra and the X-ray View of TDEs, Peter Maksym 4 Chandra and ROSAT flares First TDEs seen in ROSAT NGC 5905 (Bade et al., 1996) RX J A (Komossa & Greiner, 1999) RX J (Grupe et al., 1999) RX J (Greiner et al, 2000) Chandra follow-up with Halpern et al. (2004, left) critical to: Demonstrate nuclear location Eliminate confusion Sensitivity: 10-yr extreme (x6000) variability Spectral hardening? Still relatively soft

Wednesday, November 19, Years of Chandra: Chandra and the X-ray View of TDEs, Peter Maksym 5 Follow-up of UV/Optical Flares UV/X-ray – extremely important for distinguishing optical TDEs from nuclear SNe X-ray Detections: Gezari et al. (2006, 2008, upper-right) – Chandra D3-13 ruled out pre-existing AGN with deep AEGIS observations L X ~10 43 erg/s, Γ~7, ~day-scale variability ~1 year post-disruption D1-9 L X ~3.5 x erg/s, 2 years post-disruption X-rays require hotter temperatures than UV blackbody trace different radii, physical regimes: inner disk, debris near R d Arcavi et al. (2014) – Swift PTF 09axc, ~7 x erg/s ~5 years post-disruption Non-detections Gezari et al. (2009) – Chandra D23H-1 L X <10 41 erg/s, 3 days & 116 days post-disruption Gezari et al. (2012 – lower right) – Chandra PS-10jh – disrupted helium core or (Guillochon 2014) ordinary? L x 200 days post-peak Arcavi et al. (2014) – Swift PTF 09ge (<2 x erg/s), 09djl (<2 x erg/s), ~5 years post- disruption

Wednesday, November 19, Years of Chandra: Chandra and the X-ray View of TDEs, Peter Maksym 6 Finding (and following) TDEs with Chandra Variability search in CDF: Luo et al. (2008) – upper limits, no detections..but see Luo et al. (2014) Atel 6625 – possible TDE at z~1.5 ?!? CXO J – Gradually decaying ULX in GC of NGC 1399 (Fornax) [O III] and [N II] but no Balmer... evidence for a TDE? (Irwin et al, 2010, left) Consistent with TDE of red clump HB star by Msun BH (Clausen et al., 2012) See also poster by Dacheng Lin – late-term Chandra follow-up of 2XMMi J (identified in Lin et al., 2011 – right)

Wednesday, November 19, Years of Chandra: Chandra and the X-ray View of TDEs, Peter Maksym 7 Relativistic Flares! Swift J : multiple Swift-BAT triggers, regular monitoring for 3+ years Breaks the mold: Hard Spectrum, attributed to beamed line-of-sight jet (blazar analogue) (Levan et al., 2011; Burrows et al., 2011; Bloom et al., 2011; many subsequent papers) Extremely bright; ~10 48 erg/s inferred Fits t -5/3 decay for >1 yr, but highly variable – large epoch-to-epoch variations First ~500 days emission probably due to internal dissipation of jet (Burrows et al., 2011; Bloom et al., 2011, Zauderer et al, 2011, Metzger et al, 2012, Liu et al, 2012, Zou et al, 2013) Dramatic transition! Jet shuts off Chandra observation at ~610 days: Too hard disk accretion. Consistent with a forward shock? Zauderer et al (2013, UR) Inverse compton cooling in an external shock? (Kumar et al., 2013) Swift J : Another relativistic flare (Cenko et al., 2012; top, LR) Both flares localized with Chandra HRC

Wednesday, November 19, Years of Chandra: Chandra and the X-ray View of TDEs, Peter Maksym 8 Tidal Disruptions in Galaxy Clusters UL: CXO/Maksym et al./Donato et al. press release UR: Maksym et al. (2013) –A1795 LR: Maksym et al. (2010) -A1689

Wednesday, November 19, Years of Chandra: Chandra and the X-ray View of TDEs, Peter Maksym 9 Tidal Disruptions in Galaxy Clusters UL: Cappeluti: ROSAT & optical, w/X-ray error circles UR: WINGS J1348 in A1795, XMM(<500 eV) blue, Gemini red, XMM (2 arcsec) and Chandra (<0.5 arcsec) error circles (See Maksym et al. 2013; 2014; Donato et al., 2014)

Wednesday, November 19, Years of Chandra: Chandra and the X-ray View of TDEs, Peter Maksym 10 What Don't We know? How common is X-ray emission from TDEs? Is there a dichotomy between X-ray selected flares (e.g. via ROSAT, XMM-Newton [Esquej et al., 2007; 2008; Lin et al., 2011]) and optically selected flares with upper limits? How well do existing multi-band models describe X-ray evolution beyond t -5/3 (e.g. Lodato & Rossi 2009; 2011; Strubbe & Quataert 2009; 2011; Guillochon et al, 2014) Can super-Eddington accretion smother the X-ray emission (e.g. “Dougie” from ROTSE; Vinko et al., 2014) Does X-ray emission require a preferred viewing angle? Could X-ray emission occupy a preferred “phase” of TDE evolution? Modulated accretion rate (Lodato & Rossi, 2011) Evolving debris covering fraction (Strubbe & Quataert, 2009) Changing opacity Changing temperature (Lodato & Rossi 2011) How common are jets, and how do they form? What about X-ray emission/absorption lines/edges? (e.g. Strubbe & Quataert 2011) What can we learn from PDS analysis (e.g. Lin et al., 2011; Reis et al., 2012)

Wednesday, November 19, Years of Chandra: Chandra and the X-ray View of TDEs, Peter Maksym 11 Where Should We Go? Solid physical basis for optical selection Important groundwork before LSST can be used for statistical purposes More X-ray selected events with prompt multi-wavelength follow-up Chandra/XMM cluster monitoring? It would take an XVP TDEs are rare, so TDE “surveys” need to be parasitic by nature Sociological paradigm shift If you're not interested in your point sources, share them......or don't share – but do check! eROSITA Aggressive X-ray follow-up of low-z optical flares Abundance of data – easier to rule out AGN Good astrometry – easier to rule out SNe Swift can select, follow-up with Chandra/XMM Long-term monitoring – Early & Late Easiest for bright, nearby flares Check e.g. for corona formation Cooling out-of-band (e.g. Lodato & Rossi, 2011) Frequent enough to ignore stochastic variability (see, e.g. Liu et al., 2014) Maksym et al., 2014, based on Lodato & Rossi 2011; See also Khabibullin & Sazonov, 2014